bluuebunny/crossref_metadata_2025 huggingface dataset:
Absorption of dietary cholesterol oxidation products and incorporation into rat lymph chylomicrons
Authors: Vine D. F. , Croft K. D. , Beilin L. J. , Mamo J. C. L.
Published: November 2006

Cholesterol oxidation products (oxysterols) induce macrophage lipid loading and accumulate in early arterial fatty streaks. The origin of lesion oxysterols has not been elucidated. The absorption of oxysterols from the diet and transport to the arterial wall by postprandial lipoprotein remnants may be a significant source. This study aimed to investigated the extent of oxysterol absorption and the effect on chylomicron composition. Cholesterol was heat‐treated, causing 30% oxidation; the major oxidation products were 7β‐hydroxycholesterol, 7‐ketocholesterol, 5α,6α‐epoxycholesterol, and 5β,6β‐epoxycholesterol. Conscious lymph‐cannulated rats were given a bolus gastric infusion of 50 mg oxidized cholesterol or 50 mg purified cholesterol in a vehicle of triglyceride. In the rats given the oxidized cholesterol, 6% of the oxysterol load was absorbed and incorporated into lymph chylomicrons. Rats given pure cholesterol had no increase in oxysterols above baseline levels. The incorporation of oxysterols into lymph chylomicrons differed over time with 7β‐hydroxycholesterol, having peak absorption at 3 h, followed by 7‐ketocholesterol at 4 h and 5α,6α‐epoxycholesterol at 5 h. The absorption of oxysterols in animals given the oxidized cholesterol gastric infusate was associated with lymph chylomicron compositional changes at 2–4 h. The oxidized cholesterol‐treated group has a twofold increase in the cholesterol (890±84 μg vs. 440±83 μg at 3 h) and triglyceride content (19.76±3.4 μg vs. 8.49±3.8 μg at 3 h). This led to a doubling of chylomicron size over this postprandial period, with particles having a mean diameter of 294 nm in the oxidized cholesterol‐treated animals, compared to 179 nm in the purified cholesterol group. In conclusion, dietary oxysterols appear to influence postprandial lipoprotein particle size and composition. These changes may have effects on the clearance of chylomicrons from plasma, arterial delivery of oxysterols, and possible deposition in arterial lesions.
Refeeding varying fatty acid and cholesterol diets alters phospholipids in rat intestinal brush border membrane
Authors: Keelan M. , Clandinin M. T. , Thomson A. B. R.
Published: November 2006

Refeeding a diet initially given shortly after weaning results in a different adaptive change in the in vitro intestinal uptake of sugars and lipids than if the diet is given for the first time at a later age. This study was undertaken in rats to test the hypothesis that changes in nutrient uptake associated with refeeding diets containing beef tallow (S), beef tallow plus 1% cholesterol (Sc), fish oil (F), or fish oil plus cholesterol (Fc) are associated with changes in the brush border membrane (BBM) phospholipids and phospholipid fatty acids. Weanling Sprague‐Dawley rats were fed ad libitum one of the four diets. At 35 d of age (about 2 wk after weaning), the rats were maintained on either the same diet used at weaning, or were switched to one of the other semisynthetic diets which were then fed for a further 7 wk. At week nine (2+7) the rats were either continued on the same diet or were switched back to the original diet for 2 wk (2+7+2). The groups of animals which were compared included SSSc vs. ScSSc; ScScS vs. SScS; FFFc vs. FcFFc; and FcFcF vs. FFcF. Refeeding S, Sc, F, or Fc had no effect on food consumption or on body weight gain. Refeeding Fc resulted in increased ileal BBM total phospholipids, whereas rechallenge with F resulted in a decline in the jejunal BBM ratio of phospholipid/cholesterol. Refeeding Sc resulted in a decrease in the ileal BBM phosphatidylcholine (PC). In rats rechallenged with Fc, there was increased ileal BBM sphingomyelin (SM), increased ileal BBM phosphatidylethanolamine (PE), decreased ileal BBM PC/PE, and an increased ileal BBM SM/PC. Refeeding had no effect on the fatty acyl constituents of the jejunal or ileal BBM PC or PE. These results suggest that there are late effects of the early introduction of dietary cholesterol on intestinal BBM phospholipid content and composition that may contribute to the previously reported changes in intestinal nutrient absorption.
Lipase‐catalyzed monoesterification of 1‐O‐hexadecylglycerol in organic solvents
Authors: Bertello Laura E. , Salto María Laura , de Lederkremer Rosa M.
Published: November 2006

A simple method is presented to esterify 1‐O‐hexadecyl‐rac‐glycerol using lipases in different organic solvents. The following fatty acids were used: C14∶0, C16∶0, C18∶0, C18∶1, and C18∶2. Monoesterification was achieved by using a limiting amount of the fatty acid. Both the 1‐O‐hexadecyl‐3‐O‐acylglycerol and the 2‐O‐acylglycerol were obtained in a total yield of 75% and a ratio of 7∶1 in dichloromethane after 3 d. Chromatographic data for the monoesters, useful for the identification of the natural products, are given (gas‐liquid chromatography, thin‐layer chromatography, reverse‐phase thin‐layer chromatography). The structure was confirmed by a chemical synthesis of 1‐O‐hexadecyl‐2‐O‐hexadecanoylglycerol. The 3‐O‐glyceride was also formed by acyl migration, as the minor component. The monoesters were separated by column chromatography and characterized by 1H and 13C nuclear magnetic resonance spectra.
The effect of highly purified eicosapentaenoic and docosahexaenoic acids on monocyte phagocytosis in man
Authors: Dag Halvorsen Seeger , Hansen John‐Bjarne , Grimsgaard Sameline , Bønaa Kaare H. , Kierulf Peter , Nordøy Arne
Published: November 2006

The n‐3 fatty acids (FA) from marine sources are known to exert antiinflammatory effects on monocyte function. There is still controversy whether n‐3 FA may increase the susceptibility to infections. The present study was designed to assess the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHa) on monocyte phagocytosis and respiratory burst activity. Fifty‐eight healthy men were randomized to take a daily supplement of 3.8 g highly purified EPA (n=20), 3.6 g DHA (n=19), or corn oil (n=19) for 7 wk. Mononuclear leukocytes were collected, isolated, and cryopreserved prior to and after dietary supplementation. Paired samples were analyzed in the presence of autologous serum in a crossover design. Monocyte phagocytosis and respiratory burst activity were measured by flow cytometry after ingestion of Escherichia coli. Monocytes retained their phagocytic ability and respiratory burst activity after supplementation. No reduction in internalization of bacteria was registered. Dietary n‐3 FA and particularly EPA improved bacterial adherence to the monocyte surface. In the crossover experiments, there was an adverse effect of serum enriched with n‐3 FA on bacterial adherence. We conclude that monocytes retain their phagocytic potential after supplementation with purified EPA and DHA.
Effects of triolein or oleic acid on lymphatic recovery of docosahexaenoic acid given as ethyl ester and their intramolecular distribution in lymph triglyceride of rats
Authors: Ikeda Ikuo , Yoshida Hiroko , Imaizumi Katsumi
Published: November 2006

Effects of oleic acid or triolein on lymphatic recovery of docosahexaenoic acid (DHA) given as an ethyl ester were examined in rats with cannulated thoracic ducts. Lymphatic recovery of ethyl DHA given with oleic acid or triolein was significantly higher than in rats given ethyl DHA alone. DHA distrbuted almost exclusively at the 1‐and 3‐position of triglyceride in lymph collected at 0–3 h after the administration, when it was given with oleic acid or triolein. A small part of DHA distributed at the 2‐position when ethyl DHA was the sole fatty acid given. Oleic acid given as free acid or triolein with ethyl DHA was a major fatty acid at the 2‐position. Intramolecular distribution of DHA and oleic acid in lymph triglyceride was similar when ethyl DHA was given with oleic acid or triolein.
The cholesterol‐lowering effect of guar gum is not the result of a simple diversion of bile acids toward fecal excretion
Authors: Favier Marie‐Laure , Bost Pierre‐Etienne , Guittard Christine , Demigné Christian , Rémésy Christian
Published: November 2006

The effects of partially hydrolyzed, nonviscous, guar gum (PHGG) on cholesterol metabolism and digestive balance have been compared with those of native guar gum (GUAR) in rats adapted to 0.4% cholesterol diets. Both types of guar gum elicited acidic fermentations in the large intestine, but only GUAR effectively lowered plasma cholesterol (P<0.001), chiefly in the triglyceride‐rich lipoprotein fraction. The biliary bile acid excretion was significantly enhanced in rats fed GUAR (P<0.05), as well as the intestinal and cecal bile acid pool (P<0.001). In rats fed GUAR and to a lesser extent in those fed PHGG, the fecal excretion of bile acids and neutral sterol was higher than in controls (P<0.01). The digestive balance (cholesterol intake‐steroid excretion) was positive in control rats (+47 μmol/d), whereas it was negative in rats fed GUAR (−20 μmol/d), which could involve a higher rate of endogenous cholesterol synthesis. In rats fed PHGG, the steroid balance remained slightly positive. Liver 3‐hydroxy‐3‐methylglutaryl‐CoA (HMG‐CoA) reductase activity was very low (22 pmol/min/mg protein), owing to cholesterol supplementation, in control rats or in rats fed PHGG, whereas it was markedly higher (+463%) in rats fed GUAR. In conclusion, even if PHGG does alter some parameters of the enterohepatic cycle of cholesterol and bile acids, its effects are not sufficient to elicit a significant cholesterol‐lowering effect. The intestinal (ileal or cecal) reabsorption of bile acids was not reduced, but rather increased, by GUAR; nevertheless the intestinal capacities of reabsorption were overwhelmed by the enlargement of the digestive pool of bile acids. In the present model, induction of HMG‐CoA reductase probably takes place in the presence of elevated portal bile acid concentrations.
Lipids of hamster cheek pouch epithelium
Authors: Whittle Sara , Swartzendruber Donald C. , Kremer Mary , Squier Christopher A. , Wertz Philip W.
Published: November 2006

The hamster cheek pouch is a much used but incompletely understood experimental model. In particular, the cheek pouch epithelial lipids, which are important for permeability barrier function as well as other aspects of epithelial biology, have not been completely characterized. In the present study, the complete lipid class composition has been determined by thin‐layer chromatography in conjunction with photodensitometry. The major lipid classes were phospholipids, free sterols, and ceramides. Minor amounts of monohexosylceramides, sterol esters, fatty acids, and triglycerides were also present. Significant amounts of covalently bound ω‐hydroxyceramide was also detected. Transmission electron micrographs reveal extensive, largely paired, lipid bilayers in the intercellular spaces of the stratum corneum.
Lipid and fatty acid compositions of a novel docosahexaenoic acid‐producing marine bacterium
Authors: Watanabe Kazuo , Ishikawa Chikako , Ohtsuka Itsuko , Kamata Masazumi , Tomita Miho , Yazawa Kazunaga , Muramatsu Hiroshi
Published: November 2006

An unidentified bacterial strain, SCRC‐21406, isolated from the intestine of a marine fish, Glossanodon semifasciatus, produced docosahexaenoic acid at 23% (mol/mol) [=28% (w/w)] of total fatty acids in a medium containing 0.5% (wt/vol) peptone and 0.1% (wt/vol) yeast extract at 12°C under atmospheric pressure. The cell yield was 0.43 g/L. The major lipids of the strain were phosphatidylethanolamine and phophatidylglycerol. Docosahexaenoic acid was localized at the sn‐2 positions of both phospholipids. The amounts of polyunsaturated fatty acids other than docosahexaenoic acid were extremely small [<3% (mol/mol)]. Monousaturated fatty acids of the cis‐7, cis‐9 and cis‐11 types were detected.
Modulation of adjuvant‐induced arthritis by dietary arachidonic acid in essential fatty acid‐deficient rats
Authors: Chinn Kevin S. , Welsch Dean J. , Salsgiver William J. , Mehta Aniali , Raz Amiram , Obukowicz Mark G.
Published: November 2006

Controlled feeding of linoleic acid (LA) or arachidonic acid (AA) to essential fatty acid‐deficient (EFAD) rats was used to define the relationship between dietary AA and the inflammatory response evoked during adjuvant‐induced arthritis. Based on energy percentage, EFAD rats were fed AA at the human daily equivalent (1×; 5.5 mg/day) or 10 times that amount (10×; 55 mg/day) or, alternatively, 0.5× of LA (273 mg/day). Feeding of 0.5×LA restored the plasma level of AA to that in chow‐fed controls. In contrast, feeding of 1×AA only partially restored the plasma level of AA; 10×AA was required to fully replete AA. In parallel to the degree of repletion of AA in plasma, there were accompanying decreases in the levels of palmitoleic acid, oleic acid, and Mead acid. Compared to rats fed the standard laboratory chow diet (Control), edema in the primary hind footpads was decreased by 87% in EFAD, 71% in EFAD+1×AA, 45% in EFAD+10×AA, and 30% in EFAD+0.5×LA. The decrease in edema in the footpads of EFAD rats was nearly identical to the decrease in edema in the footpads of Control rats dosed with indomethacin. Hind footpad edema correlated with the final AA plasma level and eicosanoid levels extracted from hind footpad tissue, but not with neutrophil infiltration. The data showed that 0.5×LA and 10×AA, but not 1×AA, could quickly replete AA, accompanied by the synthesis of AA‐derived eicosanoids and restoration of edema. These results suggest that in humans consumption of the average daily amount of AA without concurrent ingestion of LA would not alleviate an EFAD state.
Preparation of schiff base adducts of phosphatidylcholine core aldehydes and aminophospholipids, amino acids, and myoglobin
Authors: Ravandi A. , Kuksis A. , Shaikh N. , Jackowski G.
Published: November 2006

We have prepared Schiff base adducts of the core aldehydes of phosphatidylcholine and aminophospholipids, free amino acids, and myoglobin. The Schiff bases of the ethanolamine and serine glycerophospholipids were obtained by reacting sn‐1‐palmitoyl(stearoyl)‐2‐[9‐oxo]nonanoyl‐glycerophosphocholine (PC‐Ald) with a twofold excess of the aminophospholipid in chloroform/methanol 2∶1 (vol/vol) for 18 h at room temperature. The Schiff bases of the amino acids and myoglobin were obtained by reacting the aldehyde with an excess of isoleucine, valine, lysine, methyl ester lysine and myoglobin in aqueous methanol for 18 h at room temperature. Prior to isolation, the Schiff bases were reduced with sodium cyanoborohydride in methanol for 30 min at 4°C. The reaction products were characterized by normal‐phase high‐performance liquid chromatography and on‐line mass spectrometry with electrospray ionization. The amino acids and aminophospholipids yielded single adducts. A double adduct was obtained for myoglobin, which theoretically could have accepted up to 23 PC‐Ald groups. The yields of the products ranged from 12 to 44% for the aminophospholipids and from 15–57% for the amino acids, while the Schiff base of the myoglobin was estimated at 5% level. The new compounds are used as reference standards for the detection of high molecular weight Schiff bases in lipid extracts of natural products.
Physicochemical characterization of psychosine by 1H nuclear magnetic resonance and electron microscopy
Authors: Orfi Laszlo , Larive Cynthia K. , LeVine Steven M.
Published: November 2006

Krabbe's disease is an autosomal recessive disease that affects the lysosomal enzyme galactosylceramidase. The storage of one of its substrates, psychosine (β‐galactosylsphingosine), is thought to be responsible for the induction of pathological changes. Psychosine has a free amine group which is necessary for the mediation of its toxic effects. In the present study, the physicochemical properties of psychosine were investigated. Nuclear magnetic resonance (NMR) detected pH titration was used to determine that the amine group had a pKa of 7.18±0.05. Pulsed‐field gradient NMR spectroscopy was used to determine that the diffusion coefficient of 2.8 mM psychosine in D2O at pD 4.46 or 7.04 is 1.16±0.02×10−10 m2/s or 0.77±0.02×10−10 m2/s, respectively. Negative staining electron microscopy (EM) studies of acidic and neutral solutions of psychosine also were performed. At pH 4.5, spherical structures were formed, which were relatively stable between 3, 120, and 216 h following preparation; the diameter ranged from ∼14 nm at the earliest time point to ∼18 nm at the last time point. The critical micelle concentration (CMC) was 1.26 mM at pH 4.0. At pH 7.1, the structures changed from spherical structures with a diameter of 15–23 nm, at the earliest time point, to a heterogeneous population of structures ranging from spherical structures, with a diameter of only a few nm, to irregularly shaped oblong structures that had one or more dimensions exceeding 100 nm. The NMR and EM data indicate that the deprotonation of the amine group causes psychosine to form aggregates that are unstable, which prevents a determination of the CMC at a neutral pH. These data indicate that molecular interactions of psychosine at the acidic pH of the lysosome, where it is normally digested, are more orderly than those at the pH of the cytoplasm or extracellular space where psychosine goes during disease.
Growth inhibitory effects of liposome‐associated 1‐O‐octadecyl‐2‐O‐methyl‐sn‐glycero‐3‐phosphocholine
Authors: Peters Andrew C. , Ahmad Imran , Janoff Andrew S. , Pushkareva Marina Y. , Mayhew Eric
Published: November 2006

The growth inhibitory effects of 1‐O‐octadecyl‐2‐O‐methyl‐sn‐glycero‐3‐phosphocholine (ET‐18‐OCH3) and various liposome compositions of ET‐18‐OCH3 were compared in a standardized growth inhibition assay utilizing a diverse tumor cell line panel including cell lines expressing multidrug resistance. ET‐18‐OCH3 and ELL‐12 (4∶3∶1∶2, dioleoylphosphatidylcholine/cholesterol/dioleoylphosphatidylethanolamine‐glutaric acid/ET‐18‐OCH3), an optimal liposomal ET‐18‐OCH3 formulation, inhibited growth in the micromolar range in drug‐sensitive and‐resistant cells. In general, ET‐18‐OCH3‐liposomes were about twofold less growth inhibitory than ET‐18‐OCH3. However, the known hemolytic effects of ET‐18‐OCH3 were greatly reduced, up to 20 or more times, by liposome association. The effects of ET‐18‐OCH3 and ELL‐12 were compared in intracellular [Ca2+] modulation and DNA fragmentation assays. ET‐18‐OCH3 elicited both concentration‐ and serum‐dependent transient and permanent increases in intracellular [Ca2+]. In contrast, ELL‐12 did not modulate intracellular [Ca2+]. ET‐18‐OCH3 and ELL‐12 similarly affected DNA fragmentation, which may be indicative of apoptosis. The results suggest that, although the specific growth inhibitory effects of ET‐18‐OCH3 and ELL‐12 are similar, associating ET‐18‐OCH3 with stable well‐characterized liposomes eliminates nonspecific cell membrane‐associated lytic effects.
In vitro effect of garlic powder extract on lipid content in normal and atherosclerotic human aortic cells
Authors: Orekhov Alexander N. , Tertov Vladimir V.
Published: November 2006

In the present study, the mechanism of the in vitro effect of garlic powder extract (GPE) on lipid content of cultured human aortic cells was investigated. The addition of GPE abolished atherogenic blood serum‐induced accumulation of free cholesterol, triglycerides, and cholesteryl esters in smooth muscle cells derived from uninvolved (normal) intima. In cells isolated from atherosclerotic plaque, GPE lowered these lipids. GPE inhibited lipid synthesis both in normal and atherosclerotic cells. It inhibited acyl‐CoA:cholesterol acyltransferase activity that participates in the cholesteryl ester formation and stimulated cholesteryl ester hydrolase that degrades cholesteryl esters. This may explain the lipid reduction caused by GPE in atherosclerotic cells. GPE inhibited the uptake of modified low density lipoprotein and degradation of lipoprotein‐derived cholesteryl esters, thus considerably reducing the intracellular accumulation of cholesteryl esters. This suggests the mechanism responsible for the prevention of lipid accumulation in aortic cells caused by atherogenic blood serum.
Comparative hypocholesterolemic effects of six dietary oils in cholesterol‐fed rats after long‐term feeding
Authors: Fukushima Michihiro , Matsuda Takae , Yamagishi Kiichiro , Nakano Masuo
Published: November 2006

Rats (8 wk of age) fed a conventional diet were shifted to diets containing 10% Oenothera biennis Linn oil (OBLO, linoleic acid +γ‐linolenic acid) from a wild plant, evening primrose oil (EPO, linoleic acid +γ‐linolenic acid) from a cultivated plant, bio‐γ‐linolenic acid oil from mold (BIO, palmitic acid+oleic acid+linoleic acid+γ‐linolenic acid), safflower oil (linoleic acid), palm oil (PLO, palmitic acid+oleic acid+linoleic acid), or soybean oil (linoleic acid+α‐linolenic acid) with 0.5% cholesterol for 13 wk. Though there were no significant differences in the food intake among the groups, the body weight gain of the OBLO group was significantly lower than that of other groups except for the BIO and PLO groups, and that of the EPO and SPO groups were the highest among the groups. The liver weight of the OBLO group was significantly lower than that of other groups, and that of the PLO group was the highest among the groups. The serum total cholesterol and very low density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low density lipoprotein (LDL) cholesterol concentrations of the OBLO and EPO groups were consistently lower than those in the other groups. However, those of the BIO group were higher than those in the OBLO and EPO groups. The liver cholesterol concentration of the PLO group was the highest among all groups except for the EPO group. The fecal neutral sterol and bile acid extraction of the BIO group tended to increase compared to other groups. The results of this study demonstrate that OBLO and EPO inhibit the increasing of serum total cholesterol and VLDL+IDL+LDL‐cholesterol concentrations in the presence of excess cholesterol in the diet compared with the other dietary oils.
Molecular speciation of fish sperm phospholipids: Large amounts of dipolyunsaturated phosphatidylserine
Authors: Bell M. V. , Dick J. R. , Buda Cs.
Published: November 2006

The molecular species compositions of the main diacyl phosphoglyceride classes and ether‐linked subclasses from sperm of three species of fish, sea bass Dicentrarchus labrax, Atlantic salmon Salmo salar and Chinook salmon Onchorhynchus tsawytscha, were determined. The phospholipids from sperm were highly unsaturated, dipolyunsaturated fatty acid (diPUFA) molecular species comprised 64.6 to 71.8% of phosphatidylserine (PS), 10.1 to 17.4% of phosphatidylethanolamine (PE), and 3.3 to 10.1% of phosphatidylcholine (PC). In sea bass sperm, di22∶6n‐3 phospholipid was the predominant diPUFA molecular species, but in both salmon species 22∶5n‐3/22∶6n‐3 was also a major constituent of PS. Phospholipids containing 22∶6n‐3 dominated in sea bass sperm with 16∶0/22∶6n‐3 as a major component of PC and PE, and 18∶0/22∶6n‐3 of PE and PS in addition to di22∶6n‐3 in the latter two classes. In contrast, both salmon species contained much more 20∶5n‐3 and less 22∶6n‐3 so that saturated/20∶5n‐3 and monounsaturated/20∶5n‐3 molecular species were more abundant than the corresponding molecules containing 22∶6n‐3. Ether‐linked lipids comprised 11.3–36.3% of choline and ethanolamine phosphoglycerides in each fish species. Molecular species containing 22∶6n‐3 were the major components of 1‐O‐alkyl‐2‐acyl‐glycerophosphocholine, especially 16∶0a/22∶6n‐3 in sea bass and 18∶1a/∶6n‐3 in the two salmon species, while in 1‐O‐alk‐1′‐enyl‐2‐acyl‐glycerophosphoethanolamine, 16∶0a/22∶6n‐3 was the major component in both salmon and 18∶0a/22∶6n‐3 in sea bass with 18∶1a/22∶6n‐3 abundant in all three species. In Atlantic salmon 1‐O‐alkyl‐2‐acylglycerophosphoethanolamine comprised 24.6% of ethanolamine glycerophospholipids which were predominantly 16∶0a/22∶6n‐3 and 18∶1a/22∶6n‐3. Phosphatidylinositol from sperm was dominated by stearoyl/C20 PUFA molecular species, in sea bass overwhelmingly 18∶0/20∶4n‐6, while in both salmon species 18∶0/20∶4n‐6 and 18∶0/20∶5n‐3 were equally abundant.
Lipids and buoyancy in Southern Ocean pteropods
Authors: Phleger Charles F. , Nichols Peter D. , Virtue Patti
Published: November 2006

The lipids of Clione limacina, a Southern Ocean pteropod (order Gymnosomata), contain 28% diacylglyceryl ether (DAGE) (as percentage of total lipid) whereas the pteropod Limacina helicina (order Thecosomata) lacks DAGE. The alkyl glyceryl ether diols (1‐O‐alkyl glycerols, GE) of Clione DAGE are dominated by 16∶0 (60%) and 15∶0 (21%), in contrast with deep‐sea shark liver DAGE, which is dominated by 18∶1 GE. The fatty acid profiles of Clione and Limacina are similar (28–32% polyunsaturated, 26–34% monounsaturated) as are the sterols, which include 24‐methylenecholesterol, transdehydrocholesterol, cholesterol, and desmosterol. This finding probably reflects the fact that Limacina is the major food source for Clione. Spongiobranchaea australis, another Southern Ocean pteropod (order Gymnosomata), has 0.9–1.7% DAGE, but has less lipid (3.3–4.8 mg/g lipid, wet weight) than Clione (50.8 mg/g lipid, wet weight). We propose a buoyancy role for DAGE in Clione since Limacina has bubbles for flotation which Clione lack; DAGE provides 23% more uplift than triacylglycerol at a concentration of 1.025 g/mL seawater.
Sulfoquinovosyl diacylglycerols from the alga Heterosigma carterae
Authors: Keusgen Michael , Curtis Jonathan M. , Thibault Pierre , Walter John A. , Windust Anthony , Ayer Stephen W.
Published: November 2006

An extract of the chloromonad Heterosigma carterae (Raphidophyceae), cultivated in natural seawater, contained a complex mixture of sulfoquinovosyl diacylglycerols. Palmitoyl (16:0), three isomers of hexadecenoyl (16:1 cis Δ9, Δ11, Δ13), and eicosapentenoyl (20:5) were found to be the main fatty acyl substituents. Exact double‐bond sites were determined by mass spectrometry analysis of the corresponding nicotinyl derivatives. Four major sulfoquinovosyl diacylglycerol components were partially purified and identified as 1–4 by interpretation of their nuclear magnetic resonance and mass spectral data. In addition, complete analysis of the H. carterae sulfoquinovosyl diacylglycerols was performed using high‐performance liquid chromatography combined with electrospray tandem mass spectrometry.
Measurement of apolipoprotein B in various cell lines: Correlation between intracellular levels and rates of secretion
Authors: Bakillah Ahmed , Zhou Zhangyin , Luchoomun Jayraz , Hussain M. Mahmood
Published: November 2006

We have standardized simple but sensitive enzyme‐linked immunoassays to understand a relationship between intracellular levels and secretion rates of apoB. The assays were based on commercially available antibodies and were specific to human apoB. A monoclonal antibody, 1D1, was immobilized on microtiter wells and incubated with different amounts of low density lipoproteins to obtain a standard curve. Conditioned media were added to other wells in parallel, and the amount of apoB was quantitated from a linear regression curve. To standardize conditions for the measurement of intracellular apoB, cells were homogenized and solubilized with different concentrations of taurocholate. We found that 0.5% taurocholate was sufficient to solubilize all the apoB in HepG2, Caco‐2, and McA‐RH7777 cells. Next, a standard curve was prepared in the presence of taurocholate and used to determine intracellular levels of apoB in different cell lines. The intracellular levels (pmol/mg cell protein) and the rates of secretion (pmol/mg/h) of apoB100 were positively correlated (r2=0.81, P=0.0009) in HepG2 cells. Furthermore, a positive correlation (r2=0.88, P<0.0001) was found between intracellular and secreted apoB42 in stably transfected McA‐RH7777 cells. In contrast, no correlation was observed for human apoB28 and apoB18 in stably transfected cells that were secreted either partially associated or completely unassociated with lipoproteins. These studies indicated that the rate of secretion of lipid‐associated apoB, but not the lipid‐free apoB, was tightly controlled.
The effect of dietary docosahexaenoic acid on platelet function, platelet fatty acid composition, and blood coagulation in humans
Authors: Nelson G. J. , Schmidt P. S. , Bartolini G. L. , Kelley D. S. , Kyle David
Published: November 2006

The effect of dietary docosahexaenoic acid (DHA) in the absence of eicosapentaenoic acid (EPA) has been studied infrequently in humans under controlled conditions. This 120‐d study followed healthy, adult male volunteers who lived in the metabolic research unit (MRU) of the Western Human Nutrition Research Center for the entire study. The basal (low‐DHA) diet consisted of natural foods (30 en% fat, 15 en% protein, and 55 en% carbohydrate), containing <50 mg/d of DHA, and met the recommended daily intake for all essential nutrients. The high‐DHA (intervention) diet was similar except that 6 g/d of DHA in the form of a triglyceride containing 40% DHA replaced an equal amount of safflower oil in the basal diet. The subjects (ages 20 to 39) were within −10 to +20% of ideal body weight, nonsmoking, and not allowed alcohol in the MRU. Their exercise level was constant, and their body weights were maintained within 2% of entry level. They were initially fed the low‐DHA diet for 30 d. On day 31, six subjects (intervention, group A) were placed on the high‐DHA diet; the other four subjects (controls, group B) remained on the low‐DHA diet. Platelet aggregation in platelet‐rich plasma was determined using ADP, collagen, and arachidonic acid. No statistical differences could be detected between the amount of agonist required to produce 50% aggregation of platelet‐rich plasma before and after the subjects consumed the high‐DHA diet. The prothrombin time, activated partial thromboplastin time, and the antithrombin‐III levels in the subjects were determined, and, again, there were no statistically significant differences in these three parameters when their values were compared before and after the subjects consumed the high‐DHA diet. In addition, the in vivo bleeding times did not show any significant difference before and after the subjects consumed the high‐DHA diet (9.4 ±3.1 min before and 8.0±3.4 min after). Platelets from the volunteers exhibited more than a threefold increase in their DHA content from 1.54±0.16 to 5.48±1.21 (wt%) during the DHA feeding period. The EPA content of the subjects’ platelets increased from 0.34±0.12 to 2.67±0.91 (wt%) during the high‐DHA diet despite the absence of EPA in the subjects’ diets. The results from this study on blood clotting parameters and in vitro platelet aggregation suggest that adding 6 g/d of dietary DHA for 90 d to a typical Western diet containing less than 50 mg/d of DHA produces no observable physiological changes in blood coagulation, platelet function, or thrombotic tendencies in healthy, adult males.
Pancreatic bile salt‐dependent lipase activity in serum of normolipidemic patients
Authors: Caillol Nathalie , Pasqualini Eric , Mas Eric , Valette Anne , Verine Alain , Lombardo Dominique
Published: November 2006

Bile salt‐dependent lipase (BSDL, E.C. 3.1.1.‐) is a digestive enzyme secreted by the pancreatic acinar cell. Once in the duodenum, the enzyme, upon activation by primary bile salts, hydrolyzes dietary lipid esters such as cholesteryl esters and lipid‐soluble vitamin esters. This enzyme is partially transferred from the duodenum or pancreas to the circulation where it has been postulated to exert a systemic action on atheromagenerating oxidized‐low density lipoprotein (LDL). In the present study, sera from 40 healthy normolipidemic volunteers were used to investigate the possible linkage between circulating BSDL, lipids, and lipoproteins. We showed, firstly that pancreatic‐like BSDL, activity can be detected in these serums. Secondly, BSDL activity increased significantly with the level of LDL‐cholesterol and was also positively linked to the serum concentration of Apo B100 and Apo A‐1. Thirdly, we also established that BSDL was associated with LDL, in part by a specific interaction with Apo B100, while no interaction was found with Apo A‐1. No linkage with other recorded parameters (triglycerides, phospholipids, and high density lipoprotein‐cholesterol) was detected. Because an increase in LDL‐cholesterol represents an important risk factor for atheroma, the concomitant increase in BSDL, which can metabolize atherogenic LDL, suggests for the first time that this circulating enzyme may exert a positive effect against atherosclerosis.
Prevention of ischemia‐induced cardiac Sudden death by n−3 polyunsaturated fatty acids in dogs
Authors: Billman George E. , Kang Jing X. , Leaf Alexander
Published: November 2006

The objective of this study was to obtain functional information associated with the prevention by n−3 polyunsaturated fatty acids (PUFA) of ischemia‐induced fatal cardiac ventricular arrhythmias in the intact, conscious, exercising dog. Thirteen dogs suceptible to ischemia‐induced ventricular fibrillation were prepared surgically by ligation of their anterior descending left coronary artery and placement of an inflatable cuff around their left circumflex artery. After 4 wk of recovery, exercise‐plus‐ischemia tests were performed without and then with an intravenous infusion of an emulsion of free n−3 PUFA just prior to occluding the left circumflex artery while the animals were running on a treadmill. One week later the exercise‐plus‐ischemia test was repeated but with a control infusion replacing the emulsion of n−3 PUFA. The infusion of the free n−3 PUFA in quantities of 1.0 to 10 g prevented ventricular fibrillation in 10 of the 13 dogs tested (P<0.005), apparently without esterification of the PUFA into membrane phospholipids. The antiarrhythmic effect of the n−3 PUFA was associated with slowing of the heart rate, shortening of the QT‐interval (electrical action potential duration), reduction of left ventricular systolic pressure, and prolongation of the electrocardiographic atrial‐ventricular conduction time (P‐R interval). These effects are comparable with those we have reported in studies with cultured neonatal rat cardiac myocytes.
Biliary excretion of dolichols and β‐hexosaminidase—Effect of ethanol and glucagon
Authors: Humaloja Kari , Salaspuro Mikko , Roine Risto P.
Published: November 2006

Alcohol has been reported to increase the urinary excretion of dolichols, and urinary dolichols are suggested to be derived from the lysosomes of the renal cells. In the present study we examined the effects of alcohol and glucagon on the biliary excretion of dolichols in rats. Chronic ethanol treatment decreased both biliary dolichol and β‐hexosaminidase excretion. The absolute amount of dolichol excreted into the bile correlated highly significantly with the absolute amount of biliary β‐hexosaminidase. Our results indicate that biliary dolichols are—at least in part—derived from hepatic lysosomes. Decreased biliary dolichol output during chronic alcohol administration suggests that urinary and biliary dolichol excretions are regulated independently of each other.
Effect of curcumin and capsaicin on arachidonic acid metabolism and lysosomal enzyme secretion by rat peritoneal macrophages
Authors: Joe Bina , Lokesh B. R.
Published: November 2006

The inflammatory mediators secreted by macrophages play an important role in autoimmune diseases. Spice components, such as curcumin from turmeric and capsaicin from red pepper, are shown to exhibit antiinflammatory properties. The influence of these spice components on arachidonic acid metabolism and secretion of lysosomal enzymes by macrophages was investigated. Rat peritoneal macrophages preincubated with 10 μM curcumin or capsaicin for 1 h inhibited the incorporation of arachidonic acid into membrane lipids by 82 and 76%: prostaglandin E2 by 45 and 48%; leukotriene B4 by 61 and 46%, and leukotriene C4 by 34 and 48%, respectively, but did not affect the release of arachidonic acid from macrophages stimulated by phorbol myristate acetate. However, the secretion of 6‐keto PG F1α was enhanced by 40 and 29% from macrophages preincubated with 10 μM curcumin or capsaicin, respectively, as compared to those produced by control cells. Curcumin and capsaicin also inhibited the secretion of collagenase, elastase, and hyaluronidase to the maximum extent of 57, 61, 66%, and 46, 69, 67%, respectively. These results demonstrated that curcumin and capsaicin can control the release of inflammatory mediators such as eicosanoids and hydrolytic enzymes secreted by macrophages and thereby may exhibit antiinflammatory properties.
Lipid specificity and location of the sterol carrier protein‐2 fatty acid‐binding site: A fluorescence displacement and energy transfer study
Authors: Frolov Andrey , Miller Kimberly , Billheimer Jeffrey T. , Cho Tae‐Hyeon , Schroeder Friedhelm
Published: November 2006

Although it was recently recognized that sterol carrier protein‐2 (SCP‐2) interacts with fatty acids, little is known regarding the specificity of SCP‐2 for long‐chain fatty acids or branched‐chain fatty‐acid‐like molecules. Likewise the location of the fatty‐acid binding site within SCP‐2 is unresolved. A fluorescent cis‐parinaric acid displacement assay was used to show that SCP‐2 optimally interacted with 14–22 carbon chain lipidic molecules: polyunsaturated fatty acids > monounsaturated, saturated > branched‐chain isoprenoids > branched‐chain phytol‐derived fatty acids. In contrast, the other major fatty‐acid binding protein in liver, fatty‐acid binding protein (L‐FABP), displayed a much narrower carbon chain preference in general: polyunsaturated fatty acids > branched‐chain phytol‐derived fatty acids > 14‐ and 16‐carbon saturated > branched‐chain isoprenoids. However, both SCP‐2 and l‐FABP displayed a very similar unsaturated fatty‐acid specificity profile. The presence and location of the SCP‐2 lipid binding site were investigated by fluorescence energy transfer. The distance between the SCP‐2 Trp50 and bound cis‐parinaric acid was determined to be 40 Å. Thus, the SCP‐2 fatty‐acid binding site appeared to be located on the opposite side of the SCP‐2 Trp50. These findings not only contribute to our understanding of the SCP‐2 ligand binding site but also provide evidence suggesting a potential role for SCP‐2 and/or L‐FABP in metabolism of branched‐chain fatty acids and isoprenoids.
Evaluating acid and base catalysts in the methylation of milk and rumen fatty acids with special emphasis on conjugated dienes and total trans fatty acids
Authors: Kramer John K. G. , Fellner Vivek , Dugan Michael E. R. , Sauer Frank D. , Mossoba Magdi M. , Yurawecz Martin P.
Published: November 2006

Milk analysis is receiving increased attention. Milk contains conjugated octadecadienoic acids (18∶2) purported to be anticarcinogenic, low levels of essential fatty acids, and trans fatty acids that increase when essential fatty acids are increased in dairy rations. Milk and rumen fatty acid methyl esters (FAME) were prepared using several acid‐(HCl, BF3, acetyl chloride, H2SO4) or base‐catalysts (NaOCH3, tetramethylguanidine, diazomethane), or combinations thereof. All acid‐catalyzed procedures resulted in decreased cis/trans (Δ9c, 11t‐18∶2) and increased trans/trans (Δ9t, 11t‐18∶2) conjugated dienes and the production of allylic methoxy artifacts. The methoxy artifacts were identified by gas‐liquid chromatography (GLC)‐mass spectroscopy. The base‐catalyzed procedures gave no isomerization of conjugated dienes and no methoxy artifacts, but they did not transesterify N‐acyl lipids such as sphingomyelin, and NaOCH3 did not methylate free fatty acids. In addition, reaction with tetramethylguanidine coextracted material with hexane that interfered with the determination of the short‐chain FAME by GLC. Acid‐catalyzed methylation resulted in the loss of about 12% total conjugated dienes, 42% recovery of the Δ9c,11t‐18∶2 isomer, a fourfold increase in Δ9t,11t‐18∶2, and the formation of methoxy artifacts, compared with the base‐catalyzed reactions. Total milk FAME showed significant infrared (IR) absorption due to conjugated dienes at 985 and 948 cm−1. The IR determination of total trans content of milk FAME was not fully satisfactory because the 966 cm−1trans band overlapped with the conjugated diene bands. IR accuracy was limited by the fact that the absorptivity of methyl elaidate, used as calibration standard, was different from those of the other minor trans fatty acids (e.g., dienes) found in milk. In addition, acid‐catalyzed reactions produced interfering material that absorbed extensively in the trans IR region. No single method or combination of methods could adequately prepare FAME from all lipid classes in milk or rumen lipids, and not affect the conjugated dienes. The best compromise for milk fatty acids was obtained with NaOCH3 followed by HCl or BF3, or diazomethane followed by NaOCH3, being aware that sphingomyelins are ignored. For rumen samples, the best method was diazomethane followed by NaOCH3.
Hematological and lipid changes in newborn piglets fed milk‐replacer diets containing erucic acid
Authors: Kramer John K. G. , Sauer Frank D. , Farnworth Edward R. , Stevenson Dan , Rock Gail A.
Published: November 2006

Canola oil is not presently permitted in infant formulations in the United States because of lack of information concenring the effects of feeding canola oil to the newborn. We have previously reported a transient decrease in platelet counts and an increase in platelet size in newborn piglets fed canola oil for 4 wk, and have confirmed this in the present study. In canola oil‐fed piglets, changes in platelet size and number were overcome by adding either long‐chain saturated fatty acids from cocoa butter (16:0 and 18:0), or shorter‐chain saturates from coconut oil (12:0 and 14:0). Feeding a high erucic acid rapeseed (HEAR) oil, with 20% 22:1n−9, led to an even greater platelet reduction and increased platelet size throughout the 4‐wk trial. Bleeding times were longer in piglets fed canola oil or HEAR oil compared to sow‐reared and soybean oil‐fed piglets. There were no other diet‐related changes. Diet‐induced platelet changes were not related to platelet lipid class composition, but there were fatty acid changes. The incorporation of 22:1n−9 into platelet phospholipids of piglets fed canola oil was low (0.2–1.2%), and even for the HEAR oil group ranged from only 0.2% in phosphatidylinositol to 2.4% in phosphatidylserine. A much greater change was observed in the concentration of 24:1n−9 and in the 24:1n−9/24:0 ratio in platelet sphingomyelin (SM). The 24:1n−9 increased to 49% in the HEAR oil group compared to about 12% in animals fed the control diets (sow‐reared piglets and soybean oil‐fed group), while the 24:1n−9/24:0 ratio increased from about 1 to 12. Even feeding canola oil, prepared to contain 2% 22:1n−9, led to a marked increase in 24:1n−9 to 29% and had a 24:1n−9/24:0 ratio of 5. The canola oil/cocoa butter group, which also contained 2% 22:1n−9, showed a lower level of 24:1n−9 (20%) and the 24:1n−9/24:0 ratio (3) compared to the canola oil group. The results suggest that the diet‐related platelet changes in newborn piglets may be related to an increase in 24:1n−9 in platelet SM, resulting from chain elongation of 22:1n−9. The inclusion of canola oil as the sole source of fat in the milk‐replacer diets of newborn piglets resulted in significant platelet and lipid changes.
Stereochemistry‐dependent inhibition of RAS farnesylation by farnesyl phosphonic acids
Authors: Hohl Raymond J. , Lewis Kriste A. , Cermak Diana M. , Wiemer David F.
Published: November 2006

This investigation compares the effects of three farnesyl pyrophosphate analogs on selected aspects of isoprenoid metabolism. E,E‐α‐Hydroxyfarnesylphosphonate was prepared by an improved variation on a literature synthesis, which also gave access to the new Z,E‐α‐hydroxyfarnesyl‐ and α‐hydroxygeranylphosphonates. A striking find is that only E,E‐α‐hydroxyfarnesylphosphonate induces alteration of RAS processing in intact human‐derived leukemia cells and inhibits farnesyl protein transferase in enzyme assays, while the Z,E‐α‐farnesyl‐ and geranylphosphonates are inactive. The inhibitory activity of E,E‐α‐hydroxyfarnesylphosphonate is greater in enzyme than intact cell assays. This active compound does not significantly inhibit geranylgeranyl protein transferase I or squalene synthase, nor does it diminish cholesterol synthesis. These results indicate that the length of the terpenoid chain and olefin stereochemistry allow selective inhibition of critical enzymes of terpenoid metabolism. Discrimination was observed between inhibition of farnesyl protein transferase and squalene synthase by E,E‐α‐hydroxyfarnesylphosphonate, even though both enzymes utilize farnesyl pyrophosphate as their natural substrate.
Biosynthesis of triacylglycerols containing ricinoleate in castor microsomes using 1‐acyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine as the substrate of oleoyl‐12‐hydroxylase
Authors: Lin Jiann‐Tsyh , Woodruff Carol L. , Lagouche Olivier J. , McKeon Thomas A. , Stafford Allan E. , Goodrich‐Tanrikulu Marta , Singleton John A. , Haney Carol A.
Published: November 2006

We have examined the biosynthetic pathway of triacylglycerols containing ricinoleate to determine the steps in the pathway that lead to the high levels of ricinoleate incorporation in castor oil. The biosynthetic pathway was studied by analysis of products resulting from castor microsomal incubation of 1‐palmitoyl‐2‐[14C]oleoyl‐sn‐glycero‐3‐phosphocholine, the substrate of oleoyl‐12‐hydroxylase, using high‐performance liquid chromatography, gas chromatography, mass spectrometry, and/or thin‐layer chromatography. In addition to formation of the immediate and major metabolite, 1‐palmitoyl‐2‐[14C]rici‐noleoyl‐sn‐glycero‐3‐phosphocholine, 14C‐labeled 2‐linoleoyl‐phosphatidylcholine (PC), and 14C‐labeled phosphatidylethanolamine were also identified as the metabolites. In addition, the four triacylglycerols that constitute castor oil, triricinolein, 1,2‐diricinoleoyl‐3‐oleoyl‐sn‐glycerol, 1,2‐diricinoleoyl‐3‐linoleoyl‐sn‐glycerol, 1,2‐diricinoleoyl‐3‐linolenoyl‐sn‐glycerol, were also identified as labeled metabolites in the incubation along with labeled fatty acids: ricinoleate, oleate, and linoleate. The conversion of PC to free fatty acids by phospholipase A2 strongly favored ricinoleate among the fatty acids on the sn‐2 position of PC. A major metabolite, 1‐palmitoyl‐2‐oleoyl‐sn‐glycerol, was identified as the phospholipase C hydrolyte of the substrate; however, its conversion to triacylglycerols was blocked. In the separate incubations of 2‐[14C]ricinoleoyl‐PC and [14C]ricinoleate plus CoA, the metabolites were free ricinoleate and the same triacylglycerols that result from incubation with 2‐oleoyl‐PC. Our results demonstrate the proposed pathway: 2‐oleoyl‐PC. Out results demonstrate the proposed pathway: 2‐oleoyl‐PC→2‐ricinoleoyl‐PC→ricinoleate →triacylglycerols. The first two steps as well as the step of diacylglycerol acyltransferase show preference for producing ricinoleate and incorporating it in triacylglycerols over oleate and linoleate. Thus, the productions of these triacylglycerols in this relatively short incubation (30 min), as well as the availability of 2‐oleoyl‐PC in vivo, reflect the in vivo drive to produce triricinolein in castor bean.