bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the interrelationship between hepatic carnitine, fatty acid oxidation, and triglyceride biosynthesis in nephrosis
Authors: AL‐Shurbaji Ayman , Berglund Lars , Berge Rolf K. , Cederblad Gitten , Humble Elisabet 
Published: November 2006

AbstractThe nephrotic syndrome is associated with disturbances in plasma lipid pattern and metabolism. However, the reason for these perturbations is poorly understood. In the present study, we have investigated hepatic triglyceride metabolism in puromycin aminonucleoside‐induced nephrotic syndrome in rats. Nephrotic rats displayed a 70% increase in hepatic triglyceride levels compared to controls (16.9±1.6 vs. 9.8±0.6 μmol/g liver; means±SEM, P<0.01). The capacity for hepatic mitochondrial β‐oxidation of fatty acids was substantially elevated (80%). This was associated with a rise in the liver content of the fatty acid carrier carnitine (1.24±0.06 vs. 0.85±0.07 μmol/g dry weight, P<0.05). A positive correlation between the levels of acetylcarnitine and acetyl‐CoA was found in normal as well as in nephrotic rats, implying that carnitine plays an important role as an acetyl group acceptor in the liver under normo‐ and hyperlipidemic conditions. Changes in carnitine levels seem to be tightly coupled to the rate of fatty acid oxidation. There was a significant elevation in the activity of phosphatidate phosphohydrolase (E.C. 3.1.3.4) in liver microsomes from nephrotic rats (1.07±0.09 vs. 0.81±0.04 nmol/min·mg protein, P<0.02). Hepatic very low density lipoprotein (VLDL)‐triglyceride secretion rate was 18% higher in nephrotic rats than in controls. The results demonstrate a deranged hepatic triglyceride metabolism in nephrosis, with an increased hepatic triglyceride biosynthesis, a sizable accumulation of hepatic triglycerides, and only a modest increase in VLDL triglyceride secretion. In addition, mitochondrial β‐oxidation of fatty acids was enhanced, associated with an increased availability of carnitine.
Effect of conjugated linoleic acid on body composition in mice
Authors: Park Yeonhwa , Albright Karen J. , Liu Wei , Storkson Jayne M. , Cook Mark E. , Pariza Michael W. 
Published: November 2006

AbstractThe effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing 5.5% corn oil or a CLA‐supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA‐supplemented diet exhibited 57% and 60% lower body fat and 5% and 14% increased lean body mass relative to controls (P<0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3‐L1 adipocytes CLA treatment (1×10−4 M) significantly reduced heparin‐releasable lipoprotein lipase activity (−66%) and the intracellular concentrations of triacylglyceride (−8%) and glycerol (−15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P<0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.
Short‐term effects of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase inhibitor on cholesterol and bile acid synthesis in humans
Authors: Yoshida Tadashi , Honda Akira , Shoda Junichi , Abei Masato , Matsuzaki Yasushi , Tanaka Naomi , Miyazaki Hiroshi , Osuga Toshiaki 
Published: November 2006

AbstractCompetitive inhibitors of 3‐hydroxy‐3‐methylglutaryl‐CoA reductase improve hypercholesterolemia. However, reports about the effects of these agents on bile acid synthesis, the metabolic pathway of cholesterol, are conflicting. We studied the short‐term effect of one of these agents, pravastatin, on bile acid synthesis. Six male volunteers were given 40 mg of pravastatin. Plasma mevalonate level (which reflects cholesterol synthesis) and 7α‐hydroxy‐4‐cholesten‐3‐one level 9which reflects bile acid synthesis) were measured every 2 h for 8 h. These plasma levels were compared to those of the same volunteers without pravastatin. Plasma mevalonate level after 2 h was lower than control (3.0 ± 1.1 ng/ml vs. 6.7 ± 2.5, mean ±SD; P<0.05). This decrease continued for 8 h (2.5 ± 0.8 vs. 5.2 ± 1.5; P<0.05). On the other hand, plasma 7α‐hydroxy‐4‐cholesten‐3‐one level did not change until after 6 h; then at 8 h it was lower than control (15.7 ± 11.8 ng/mL vs. 24.7 ± 16.9; P <0.05). According to three‐way layout analysis of variance, mevalonate level was influenced by both pravastatin treatment (P<0.01) and time‐course (P<0.01). On the other hand, the 7α‐hydroxy‐4‐cholesten‐3‐one level was affected by both individual difference (P<0.01) and time course (P<0.01), but pravastatin treatment did not influence this compound. This indicates that bile acid synthesis was not influenced by pravastatin, although cholesterol synthesis was inhibited. The shortterm inhibition of cholesterol synthesis did not affect bile acid synthesis.
Oxidation of cholesterol in synaptosomes and mitochondria isolated from rat brains
Authors: Vatassery Govind T. , Quach Hung T. , Smith W. Ed , Ungar Frank 
Published: November 2006

AbstractCholesterol and α‐tocopherol oxidations were studied in brain subcellular fractions isolated from cerebral hemispheres of 4‐month‐old, male Fischer 344 rats. The fractions were suspended in buffered media (pH 7.4, 37°C) and oxidized by adding (i) ferrous iron (Fe2+) with or without ascorbate or (ii) peroxynitrite (an endogenous oxidant produced by the reaction of superoxide and nitric oxide). Treatment of subcellular fractions with Fe2+ in the presence or absence of ascorbate produced primarily 7‐keto‐ and 7‐hydroxy‐cholesterols and small amounts of 5α,6α‐epoxycholesterol. Since brain contains high levels of ascorbate, any release of iron could result in oxysterol formation. Peroxynitrite oxidized α‐tocopherol but not cholesterol. Hence, the toxicity of peroxynitrite or nitric oxide could not be due to cytotoxic oxysterols. When synaptosomes were incubated for 5 min in the presence of 0.5 to 2 μM Fe2+ and ascorbate, α‐tocopherol was oxidized while cholesterol remained unchanged. Thus, α‐tocopherol is functioning as an antioxidant, protecting cholesterol. Diethylenetriaminepentaacetic acid blocked production of oxysterols, whereas citrate, ADP and EDTA dit not. A significant percentage of mitochondrial cholesterol was oxidized by treatment with Fe2+ and ascorbate. Hence, mitochondrial membrane properties dependent on cholesterol could be particularly susceptible to oxidation. The oxysterols formed were retained within the membranes of synaptosomes and mitochondria. The 7‐oxysterols produced are known to be inhibitors of membrane enzymes and also can modify membrane permeability. Hence, oxysterols may play an important role in brain tissue damage during oxidative stress.
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

AbstractCholesterol 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

AbstractRefeeding 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

AbstractA 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

AbstractThe 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

AbstractEffects 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

AbstractThe 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

AbstractThe 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

AbstractAn 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

AbstractControlled 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

AbstractWe 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.