bluuebunny/crossref_metadata_2025 huggingface dataset:
Stearic acid modifies very low density lipoprotein lipid composition and particle size differently from shorter‐chain saturated fatty acids in cultured rat hepatocytes
Authors: Pai Tonkun , Yeh Yu‐Yan
Published: November 2006

Stearic acid as compared to myristate, palmitate, or oleate is poorly incorporated into triacylglycerol, a major lipid component of very low density lipoprotein (VLDL). The present study investigated the effects of these fatty acids on VLDL metabolism in cultured rat hepatocytes. All fatty acids stimulated [2‐3H] glycerol incorporation into VLDL lipids and secretion of [3H]‐labeled VLDL by hepatocytes. However, the rate of [3H]‐labeled VLDL secretion in the presence of nonlabeled stearate (12.8±0.7 pmol/mg protein/4h) was 46, 59, and 22% of that observed for those treated with myristate, palmitate, and oleate, respectively. [1‐14C]Stearate as a substrate was also less effective than other labeled fatty acids to be incorporated into VLDL lipids. Of total VLDL lipids synthesized from [1‐14C] stearate, triacylglycerol accounted for 78% as compared to 88–97% of that derived from palmitate, myristate, and oleate. The amounts of apoB100 and apoB48 were the same in hepatocytes treated with or without exogenous fatty acids. Similarly, the rate of apoB synthesis from [35S] methionine was not affected by exogenous fatty acids. The treatment of cells with various saturated fatty acids increased the particle size of VLDL to different extents. The largest particles of VLDL, with a mean diameter of 79.3±11.9 nm, were seen in the cells treated with stearate, followed by those treated with palmitate and myristate (45.5±9.8 and 38.6±6.8 nm, diameter, respectively). Clearly, hepatocytes treated with stearate secrete less VLDL and produce larger VLDL particles than those treated with shorter‐chain saturated fatty acids.
Impaired cholesterol esterification in the plasma in patients with breast cancer
Authors: Subbaiah Papasani V. , Liu Ming , Witt Thomas R.
Published: November 2006

An important factor which determines the movement of cholesterol in and out of the cells is the free cholesterol (FC)/esterified cholesterol (EC) ratio in the plasma. Although this ratio has been shown to be increased in several types of malignancies in humans as well as experimental animals, it is not known whether such an abnormality is found in breast cancer patients. Furthermore, the reasons for such an increase in cancer patients are unknown. We studied the plasma lipid composition and the activity of lecithin‐cholesterol acyltransferase (LCAT), the enzyme responsible for the formation of most of EC in human plasma, in 12 women with breast cancer and 9 agematched control women. The plasma EC concentration was found to be significantly decreased in cancer patients, whereas the FC concentration was unchanged, leading to increased FC/EC ratios (P<0.05). The concentration of phosphatidylcholine, the acyl donor in the LCAT reaction, was decreased significantly, whereas all other phospholipids were unaffected. The cholesterol‐esterifying activity of LCAT was significantly lower in cancer patients, whether assayed with endogenous substrates (P<0.05), or with an exogenous substrate (P<0.01). However, another function of the enzyme, namely the lysolecithin acyltransferase activity, was increased (P<0.02), indicating that the enzyme concentration in plasma may not be decreased. These results show that the increase in the FC/EC ratio in cancer patients is due to an impaired esterification of cholesterol by plasma LCAT, probably due to an alteration in the composition of substrate lipoproteins, or the presence of an inhibitory factor.
Early dietary intervention with structured triacylglycerols containing docosahexaenoic acid. Effect on brain, liver, and adipose tissue lipids
Authors: Christensen Merete Myrup , Høy Carl‐Erik
Published: November 2006

Newborn rats were fed liquid diets containing 7 wt% fat in which 3.8% of the total fatty acids were 22:6n‐3. The fats were either a specific structured oil with 22:6n‐3 mostly located in the sn‐2 position or a randomized oil with 22:6n‐3 equally distributed in the triacylglycerol (TAG) molecules. The oils were manufactured by interesterification of fish oil TAG with free fatty acids from butterfat. The pups were tube‐fed three times a day and stayed with their dams during the night. After 14 d they were fed solid diets containing the same oils for the next 7 d. A reference group stayed with the dams and received ordinary rat chow at weaning. In general no significant differences between the two dietary treatments were observed in the tissues examined except for adipose tissue. The levels of 22:6n‐3 were significantly increased in brain phosphatidylcholines (PC) and phosphatidylserines (PS) of both experimental groups compared with the reference group after three weeks, whereas no differences were found in brain phosphatidylethanolamines (PE) and phosphatidylinositols (PI). In all groups and all phospholipids examined, the levels of 20:4n‐6 generally decreased from 1 to 3 wk and were significantly lower in the experimental groups compared with the reference group at 3 wk except for PI. In liver, PC and PE 22:6n‐3 remained constant in the experimental groups but decreased significantly in the reference group, whereas in liver PS 22:6n‐3 increased in all groups, but reached significantly higher levels in the experimental groups than in the reference group. In adipose tissue, 22:6n‐3 increased in the experimental groups during the study period, but decreased in the reference group, suggesting that a surplus of dietary 22:6n‐3 was stored.
Phospholipid fatty acid composition in type I and type II rat muscle
Authors: Blackard William G. , Li Jing , Clore John N. , Rizzo William B.
Published: November 2006

The fatty acid composition of the membrane phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine in insulin‐sensitive Type I (soleus) and insulin‐resistant Type II (EDL) muscle is not known. In the present studies, soleus and EDL muscles were removed from 250–300 g Sprague‐Dawley rats, and the fatty acid composition of total and individual phospholipid (PL) species was quantitated. As expected, triglyceride content was increased twofold in soleus muscle. No quantitative differences in the individual PL species or cholesterol content were found between the two muscles. However, a striking difference in PL fatty acid composition was observed in the PC fraction. An increase in 16∶0 with decreases in 18∶0, 18∶1, 22∶5n‐3, and 22∶6n‐3 (P<0.001 for each) was observed in the PC fraction of EDL compared to that from soleus, consistent with reduced elongation of PC fatty acids. Inhibition of fatty acid oxidation with the carnitine palmitoyl transferase‐1 inhibitor, etomoxir, did not alter the fatty acid pattern in either muscle. We conclude that an alteration in PL fatty acid composition consistent with reduced elongation of both saturated and unsaturated fatty acids is observed in Type II muscle. The restriction of these alterations to the PC fraction has important implications.
Conjugated linoleic acid modulates hepatic lipid composition in mice
Authors: Belury Martha A. , Kempa‐Steczko Anna
Published: November 2006

Conjugated linoleic acid (CLA) is a chemoprotective fatty acid that inhibits mammary, colon, forestomach, and skin carcinogenesis in experimental animals. We hypothesize that the ubiquitous chemoprotective actions of dietary CLA in extrahepatic tissues are dependent upon its role in modulating fatty acid composition and metabolism in liver, the major organ for lipid metabolism. This study begins to evaluate the role of CLA in lipid metabolism by determining the modulation of fatty acid composition by CLA. Female SENCAR mice were fed semipurified diets containing 0.0% (Diet A), 0.5% (Diet B), 1.0% (Diet C), or 1.5% (Diet D) CLA (by weight) for six weeks. Mice fed Diets B, C, and D exhibited lower body weights and elevated amounts of extractable total lipid in livers compared with mice fed diets without CLA (Diet A). Analyses of the fatty acid composition of liver by gas chromatography revealed that dietary CLA was incorporated into neutral and phospholipids at the expense of linoleate in Diets B, C, and D; oleate increased and arachidonate decreased in neutral lipids of CLA diet groups. In addition, increasing dietary CLA was associated with reduced linoleate in hepatic phospholipids. In an in vitro assay, CLA was desaturated to an unidentified 18:3 product to a similar extent as linoleate conversion to γ‐linolenate (9.88, and 13.63%, respectively). These data suggest that CLA may affect metabolic interconversion of fatty acids in liver that may ultimately result in modified fatty acid composition and arachidonate‐derived eicosanoid production in extrahepatic tissues. In addition to determining how dietary CLA modulates eicosanoid synthesis, further work is needed to identify enzymatic products that may result from desaturation of CLA.
Effects of cationic liposome‐DNA complexes on pulmonary surfactant function in vitro and in vivo
Authors: Boncuk Pinar , Kaser Matthew , Yu Yip , Taeusch H. William
Published: November 2006

Cationic liposome‐DNA complexes are being evaluated as potential gene therapy agents for the lung. Cations have strong effects on the biophysical functions of lung surfactant. Therefore, we assessed whether cationic liposomes [composed of N‐(1‐(2,3‐dioleyloxy) propyl)‐N,N,N‐trimethyl‐ammonium chloride and dioleylphosphatidylethanolamine] with or without DNA affect behavior of four types of surfactant in vitro. Experiments were carried out using a modified Wilhelmy surface balance. The ability of surfactants that contain protein and anionic lipids to lower surface tension was inhibited in the presence of cationic liposomes. Inactivation was less when DNA was preincubated with cationic liposomes. Surfactant that contained neither protein nor anionic lipids was not inactivated. Mechanical properties of the lung were studied to assess in vivo surfactant function after intratracheal instillation of a cationic liposome‐DNA complex into adult rats. Pressure‐volume deflation curves were shifted by 18% compared with those from normal (untreated) animals, but this effect was transient and not different from that observed in animals who received a similar volume of saline. These findings indicate that cationic liposomes alone may have deleterious effects on behavior of some surfactants possibly by disrupting charge interactions between negatively charged phospholipids and surfactant proteins. When DNA is added to liposomes before exposure to surfactants, the adverse charge interactions may be obviated by charge neutralization of liposomes by DNA.
Simvastatin impairs mitogen‐induced proliferation of malignant B‐lymphocytes from humans—in vitro and in vivo studies
Authors: Vitols S. , Angelin B. , Juliusson G.
Published: November 2006

Chronic lymphocytic leukemia (CLL) cells express lower low density lipoprotein (LDL) receptor activity and higher 3‐hydroxy‐3‐methylglutaryl‐CoA (HMG‐CoA) reductase activity than normal mononuclear blood cells indicating that CLL cells may depend on cholesterol synthesis for their proliferation. We studied the effects of competitive inhibitors of HMG‐CoA reductase on malignant lymphocyte proliferation in vitro and in vivo. Tumor B‐cells from 13 patients with CLL, hairy cell leukemia, or immunoblastic B‐cell lymphoma were cultured for 4 d in the presence of B‐cell mitogens and cholesterol synthesis inhibitors. Simvastatin and lovastatin suppressed, in a concentration‐dependent manner, the mitogen‐induced cellular thymidin uptake in medium with 10% human AB‐serum or lipoprotein‐deficient serum. Pravastatin was active only in medium with lipoprotein‐deficient serum. Ten previously untrated patients with CLL received simvastatin orally, 40 mg daily for 12 wk. Mean reductions in total plasma and LDL cholesterol were 30% (range 9–46%) and 37% (range 16–63%), respectively. Cells from four patients showed moderate to minor increases in the degradation rate of 125I‐LDL suggesting that the need for exogenous cholesterol had increased, three patients showed an increase in HMG‐CoA reductase activity, and the cells from one patient showed both. There was no significant change in the clinical disease status during medication. However, four of the ten patients developed a therapy‐demanding progressive disease during the subsequent year. Further clinical studies with cholesterol synthesis inhibitors in leukemia are warranted.
Polyunsaturated fatty acids increase the sensitivity of 36B10 rat astrocytoma cells to radiation‐induced cell kill
Authors: Vartak Sujata , Robbins Mike E. C. , Spector Arthur A.
Published: November 2006

Polyunsaturated fatty acids (PUFA) such as γ‐linolenic acid (GLA, 18:3n‐6), eicosapentaenoic acid (EPA, 20: 5n‐3), and docosahexaenoic acid (DHA, 22:6n‐3) have been shown to be cytotoxic to tumor cells. The objective of this work was to study the effect of PUFA on the radiation response of a 36B10 rat astrocytoma cell line. Supplementation of the astrocytoma cells with 15–45 μM GLA, EPA, or DHA produced marked changes in the fatty acid profiles of their phospholipids and neutral lipids. The methylene bridge index of these lipids increased significantly. These PUFA also exerted cytotoxic effects, as determined using the clonogenic cell survival assay. While GLA and DHA produced a moderate cell‐killing effect, EPA was extremely cytotoxic, especially at a concentration of 45 μM. The monounsaturated oleic acid (OA, 18:1n‐9) did not affect cell survival. Further, all three PUFA, and particularly GLA, increased the radiation‐induced cell kill; OA did not enhance the effect of radiation. α‐Tocopherol acetate blocked the enhanced radiation sensitivity of GLA‐ and DHA‐supplemented cells. In conclusion, GLA, EPA, and DHA supplementation prior to, during, and after irradiation can enhance the radiation‐induced cytotoxicity of rat astrocytoma cells. GLA and DHA supplementation post‐irradiation also enhanced the radiation response of the 36B10 cells. Because GLA maximally increases the radioresponsiveness of a rat astrocytoma, this PUFA might prove useful in increasing the therapeutic efficacy of radiation in the treatment of certain gliomas.
Oryzanol decreases cholesterol absorption and aortic fatty streaks in hamsters
Authors: Rong Ni , Ausman Lynne M. , Nicolosi Robert J.
Published: November 2006

Oryzanol is a class of nonsaponifiable lipids of rice bran oil (RBO). More specifically, oryzanol is a group of ferulic acid esters of triterpene alcohol and plant sterols. In experiment 1, the mechanisms of the cholesterol‐lowering action of oryzanol were investigated in 32 hamsters made hypercholesterolemic by feeding chow‐based diets containing 5% coconut oil and 0.1% cholesterol with or without 1% oryzanol for 7 wk. Relative to the control animals, oryzanol treatment resulted in a significant reduction in plasma total cholesterol (TC) (28%, P<0.01) and the sum of IDL‐C, LDL‐C, and VLDL‐C (NON‐HDL‐C) (34%, P<0.01). In addition, the oryzanol‐treated animals also exhibited a 25% reduction in percent cholesterol absorption vs. control animals. Endogenous cholesterol synthesis, as measured by the liver and intestinal HMG‐CoA reductase activities, showed no difference between the two groups. To determine whether a lower dose of oryzanol was also efficacious and to measure aortic fatty streaks, 19 hamsters in experiment 2 were divided into two groups and fed for 10 wk chow‐based diets containing 0.05% cholesterol and 10% coconut oil (w/w) (control) and the control diet plus 0.5% oryzanol (oryzanol). Relative to the control, oryzanol‐treated hamsters had reduced plasma TC (44%, P<0.001), NON‐HDL‐C (57%, P<0.01), and triglyceride (TG) (46%, P<0.05) concentrations. Despite a 12% decrease in high density lipoprotein cholesterol (HDL‐C) (P<0.01), the oryzanol‐treated animals maintained a more optimum NON‐HDL‐C/HDL‐C profile (1.1±0.4) than the contorl (2.5±1.4; P<0.0075). Aortic fatty streak formation, so defined by the degree of accumulation of Oil Red O‐stained macrophage‐derived foam cells, was reduced 67% (P<0.01) in the oryzanol‐treated animals. From these studies, it is concluded that a constituent of the nonsaponifiable lipids of RBO, oryzanol, is at least partially responsible for the cholesterol‐lowering action of RBO. In addition, the cholesterol‐lowering action of oryzanol was associated with significant reductions in aortic fatty streak formation.
Effect of nicotine on lipoprotein metabolism in rats
Authors: Ashakumary L. , Vijayammal P. L.
Published: November 2006

Nicotine, a major component of cigarette smoke, plays an important role in the development of cardiovascular disease and lung cancer in smokers. The effect of nicotine on lipoprotein metabolism was studied using rats as the experimental animal. There was a significant increase in the total cholesterol, phospholipids, and triglycerides as well as the amount of lipids associated with very low density lipoprotein (VLDL) and low density lipoprotein (LDL) in sera of nicotine‐treated rats. The incorporation of 3H labeled leucine into the apo B was found to be increased both in the medium and associated cells in the hepatocytes isolated from nicotine‐treated rats indicating an increased synthesis and secretion of the apo B containing lipoproteins. This was further confirmed by the higher incorporation of 14C acetate into total and individual lipids of LDL and VLDL secreted into the medium as well as that associated with different lipids in the cell layer. The activity of lipoprotein lipase in extrahepatic tissues and plasma lecithin cholesterol acyltransferase activity were significantly lower in nicotine‐treated rats. These results indicate that nicotine exerts hyperlipidemic effects particularly by increasing the synthesis and secretion of triglyceride‐rich lipoproteins. Since nicotine is one of the major hazardous components present in cigarette smoke and tobacco, one can extrapolate that the deleterious effect exerted by nicotine on rats extends to cigarette smokers and those who use other forms of tobacco.
A rapid method for the determination of vitamin E forms in tissues and diet by high‐performance liquid chromatography using a normal‐phase diol column
Authors: Kramer John K. G. , Blais Lisa , Fouchard Robert C. , Melnyk Roman A. , Kallury Krishna M. R.
Published: November 2006

This paper describes a simple method for the analysis of tocopherols in tissues by which frozen tissues −70°C were pulverized at dry ice temperatures (−70°C) and immediately extracted with hexane. There was no need to remove the coeluting lipids from tissues by saponification, since at that level of neutral lipids in the sample, there was no reduction in fluorescence response. For the analysis of oil, in which large amounts of neutral lipids were coextracted, a 20% reduction of fluorescence response was observed, but the response was equal for all tocopherol forms, and was appropriately corrected. Saponification was used only when tocopherol esters were present, and only after an initial hexane extraction to remove the free tocopherols in order to avoid their loss by saponification, particularly non α‐tocopherol and tocotrienols. All the tocopherols and tocotrienols were separated on a normal‐phase diol (epoxide) column that gave consistent and reproducible results, without the disadvantages of nonreproducibility with silica columns, or the lack of separation with reversed‐phase columns. The tocopherols were quantitated by using a tocopherol form not present in the sample as an internal tocopherol standard, or using an external tocopherol standard if all forms were present, or when the sample was saponified. Piglet heart and liver samples showed the presence of mainly α‐tocopherol, with minor amounts of β‐ and γ‐tocopherol and α‐tocotrienol, but no δ‐tocopherol. Only small amounts of tocopherol esters were present in the liver but not in the heart.
Analysis of lipoxygenase‐derived fatty acid hydroperoxides by electrospray ionization tandem mass spectrometry
Authors: Schneider Claus , Schreier Peter , Herderich Markus
Published: November 2006

A rapid method is described for the identification of fatty acid hydroperoxides by electrospray ionization‐tandem mass spectrometry coupled to liquid chromatography without any derivatization required prior to analysis. Localization of fatty acid hydroperoxides in complex mixtures was achieved by monitoring the loss of hydrogen peroxide using constant neutral loss scanning. In the presence of 5 mM NH4OAc in methanol‐water, adductions [M+NH4]+ were formed almost exclusively, directly revealing the molecular mass of the thermolabile hydroperoxides. In addition, low energy collision‐induced dissociation of precursor ions [M+NH4]+ led to characteristic product ions from both the 9‐ and 13‐regioisomers. Thus, electrospray ionization‐tandem mass spectrometry provides a straightforward approach for the study of the regioselectivity of lipoxygenase catalysis without any derivatization step required prior to analysis.
Stable‐isotope method for determining the gastrointestinal handling of [1‐13C]Palmitic acid
Authors: Stolinski Michael , Murphy Jane L. , Jones Amanda E. , Jackson Alan A. , Wootton Stephen A.
Published: November 2006

The 13C enrichment in individual fatty acids extracted from human feces following the oral administration of [1‐13C]palmitic acid has been determined using a novel approach based upon gas chromatography‐isotope ratio mass spectrometry. The method was established and tested for precision and repeatability. Analytical precision was determined from 10 repeated injections of a sample containing 16∶0 and 18∶0 with levels of δ13C abundance measured at −34.01±0.60 and −23.62±0.95 delta per mil (parts per thousand) (‰), respectively (mean±SD). For the repeatability study, measurement of enrichment of the same mixture of unlabeled fatty acid methyl ester (FAME) standards (13∶0, 14∶0, 16∶0, and 18∶0) was found to have standard deviations (0.45, 0.56, 1.46 and 1.54‰ respectively). When labeled [1‐13C]palmitic acid was serially diluted with naturally enriched palmitic acid, a linear relationship was obtained to a dilution of 10% enriched compound (530‰). FAME were prepared from two fecal samples from a normal healthy adult; the first, a baseline specimen, containing no added label and the second, followed a single oral dose of [1‐13C]palmitic acid and was enriched. Enrichment in 13C was confined to the solvent‐soluble fraction following lipid extraction, and was only identified with prior acidification. The enrichments were measured in triplicate, baseline sample −32.66±0.5‰ enriched sample +268.61±8.0‰ Enrichment was restricted to the labeled species consumed, 16∶0. The methodology described here allows for the separation of compounds prior to the determination of enrichment and can be utilized to contribute to a more complete description of the gastrointestinal handling of labeled substrates than previously obtained.
Dietary docosahexaenoic acid as a source of eicosapentaenoic acid in vegetarians and omnivores
Authors: Conquer Julie A. , Holub Bruce J.
Published: November 2006

The utilization of dietary docosahexaenoic acid (DHA; 22:6n−3) as a source of eicosapentaenoic acid (EPA; 20:5n−3) via retroconversion was investigated in both vegetarians and omnivores. For this purpose, an EPA‐free preparation of DHA was given as a daily supplement (1.62 g DHA) over a period of 6 wk. The dietary supplement provided for a marked increase in DHA levels in both serum phospholipid (from 2.1 to 7.1 mol% in vegetarians and 2.2 to 7.6 mol% in omnivores) and platelet phospholipid (from 1.1 to 3.4 mol% in vegetarians and 1.4 to 3.9 mol% in omnivores). EPA levels rose to a significant but much lesser extent, while 20:4n−6, 22:5n−6, and 22:5n−3 all decreased. Based on the serum phospholipid data, the retroconversion of DHA to EPA in vivo was estimated to be 9.4% overall with no significant difference between omnivores and vegetarians.
Bile acid metabolism in young‐old parabiotic rats
Authors: Uchida Kiyohisa , Takase Haruto , Nomura Yasuharu , Satoh Takashi , Igimi Hirotsune , Takeuchi Nozomu
Published: November 2006

Serum cholesterol, triglyceride and phospholipid levels, liver cholesterol concentration, bile flow, biliary cholesterol, phospholipid and bile acid secretion rates, fecal sterol and bile acid levels and their bile acid compositions were examined in young‐old parabiotic rats and compared with those in young and old control rats and young‐young parabiotic rats. Bile acid composition was expressed in terms of the cholic acid group/chenodeoxycholic acid group (CA/CDCA) ratio. Body weight (BW) gain decreased after parabiosis especially in old rats, but the liver weight (g/100 g BW), diet‐intake, feces dry weight, liver cholesterol concentration and fecal sterol level were almost the same in all the groups. The biliary bile acid secretion rate was higher and the fecal bile acid level was lower in old rats than those in young rats but both the levels became comparable with those in young rats after parabiosis of old rats with young rats. Young rats, however, showed no changes in these levels after parabiosis. The serum cholesterol level and the biliary and fecal CA/CDCA ratios in old rats were higher than those in young rats but decreased after parabiosis with young rats, although they were still higher than those in young rats. The serum cholesterol level in young rats increased after parabiosis with old rats, but not after parabiosis with young rats, and the fecal bile acid level and the CA/CDCA ratio were not changed in either case. It is concluded from these findings that the serum cholesterol level and the CA/CDCA ratio increased with age and that these increases were prevented after parabiosis with young rats, while young rats, although their serum cholesterol level was increased, showed no increase in the CA/CDCA ratio after parabiosis with old rats.
Comparative hypocholesterolemic effects of capybara (Hydrochoerus hydrochaeris dabbenei) oil, horse oil, and sardine oil in cholesterol‐fed rats
Authors: Fukushima Michihiro , Takayama Yasuyoshi , Habaguchi Tsuyoshi , Nakano Masuo
Published: November 2006

The hypocholesterolemic efficacy of various polyunsaturated fatty acids was compared in rats given cholesterol‐enriched diets. Capybara oil (CO, linoleic+α‐linolenic acids), horse oil (HO, α‐linolenic acid), and sardine oil (SO, eicosapentaenoic+docosahexaenoic acids) were added to diets at 50 g/kg. The weight gain, food intake, and liver weight in the CO‐fed group were significantly higher than those in other groups during the 6‐wk experimental period. The serum total and very low density lipoprotein (VLDL)+intermediate density lipoprotein (IDL)+low density lipoprotein (LDL) cholesterol concentrations of the CO‐fed and SO‐fed groups were significantly lower than in the HO‐fed group after 6 wk. The serum high density lipoprotein cholesterol concentration in the SO‐fed group was significantly higher than that in the CO‐fed and HO‐fed groups. The fecal neutral sterol concentration in the CO‐fed group was reduced significantly compared with the other groups, and the fecal bile acid concentration in the HO‐fed group was significantly higher than that in the SO‐fed group. The results of this study demonstrate that CO lowers the serum total cholesterol and VLDL+IDL+LDL‐cholesterol concentrations in the presence of excess cholesterol in the diet as well as SO.
High levels of dietary arachidonic acid triglyceride exhibit no subchronic toxicity in rats
Authors: Koskelo E. ‐K. , Boswell K. , Carl L. , Lanoue S. , Kelly C. , Kyle D.
Published: November 2006

Arachidonic acid (AA), an n−6 long‐chain polyunsaturated fatty acid (LC‐PUFA), serves an important role in the body as a structural fatty acid of many tissues including neurological tissues. It is also a precursor of the n−6 class of eicosanoids and is the most abundant n−6 LC‐PUFA found in human breast milk. We have optimized the production of a microfungal source of a triglyceride oil (ARASCO®) which is enriched in AA to about 40% by weight. To establish the safety of this oil as a food, we evaluated the effect of ARASCO® in Sprague‐Dawley rats (20/sex/group) gavaged at dose levels of 1.0 and 2.5 g/kg/d for a period of 90 d, paying special attention to any potential neurotoxicity of the oil. Two groups of control animals received either untreated standard laboratory diet (untreated control) or the same diet and vehicle oil at the same dose volume administered to the treated animals (vehicle control). Physical observations, ophthalmoscopic examinations, body weight, food consumption, clinical chemistry, hematology parameters, neurobehavioral assessments, and macroscopic as well as microscopic postmortem evaluations were performed. Tissue fatty acid analyses indicated that the AA levels in the brain, heart, and liver of the high‐dose ARASCO®‐fed animals increased by 8, 59, and 76%, respectively, indicating that the AA in the oil was readily incorporated into tissue lipids. In spite of this high elevation in tissue AA levels, no developmental, histopathological, or neuropathological differences were seen in the animals administered ARASCO® compared with the vehicle control animals. Being highly enriched in AA, ARASCO® offers the means to study the effect of this fatty acid in experimental settings and in human metabolic studies.
Possible fatty acyl pheromone precursors in Spodoptera littoralis. Search for 11‐ and 12‐hydroxytetradecanoic acids in the pheromone gland
Authors: Navarro Isabel , Fabriàs Gemma , Camps Francisco
Published: November 2006

Lipidic extracts of Spodoptera littoralis pheromone glands submitted to acid methanolysis using: (i) sulfuric acid/methanol/benzene (0.1∶4∶2, by vol) at 90°C for 1 h; (ii) 12 N HCl/methanol (1∶2; vol/vol) at 90°C for 1 h, or (iii) 14% BF3‐MeOH at 90°C for 1 h did not reveal the presence of either 11‐ or 12‐hydroxytetradecanoic acid in the extracts, as concluded from the gas chromatography‐mass spectrometry analyses. Under the above methanolysis conditions, a synthetic sample of methyl (14, 14, 15‐2H3) 12‐hydroxytetradecanoate remained unaltered. These results may indicate that formation of (E)‐11‐tetradecenoic acid from tetradecanoic acid does not occur in the pheromone gland by dehydration of an intermediate hydroxyacid. Acid methanolysis of a lipidic extract using BF3‐MeOH led to the formation of a mixture of methoxy fatty acid methyl esters, identified by gas chromatography‐mass spectrometry. These methoxy derivatives should arise from BF3‐catalyzed addition of methanol to the double bond of the natural monounsaturated fatty acyl derivatives present in the gland. Thus, under the same conditions, a synthetic sample of methyl (Z)‐11‐tetradecenoate was partially transformed into methyl 11‐methoxytetradecanoate and methyl 12‐methoxytetradecanoate. This reaction might be a useful alternative procedure to obtain methoxy derivatives of olefins, which are very helpful for the structural characterization of the parent alkenes.
A human dietary arachidonic acid supplementation study conducted in a metabolic research unit: Radionale and design
Authors: Nelson G. J. , Kelly D. S. , Emken E. A. , Phinney S. D. , Kyle David , Ferretti Aldo
Published: November 2006

While there are many reports of studies that fed arachidonic acid (AA) to animals, there are very few reports of AA feeding to humans under controlled conditions. This 130‐d study was conceived as a controlled, symmetrical crossover design with healthy, adult male volunteers. They lived in the metabolic research unit (MRU) of the Western Human Nutrition Research (WHNRC) for the entire study. All food was prepared by the WHNRC kitchen. The basal (low‐AA) diet consisted of natural foods (30 en% fat, 15 en% protein, and 55 en% carbohydrate), containing 210 mg/d of AA, and met the recommended daily allowance for all nutrients. The high‐AA (intervention) diet was similar except that 1.5 g/d of AA in the form of a triglyceride containing 50% AA replaced an equal amount of high‐oleic 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. Subjects were initially fed the low‐AA diet for 15 d. On day 16, half of the subjects (group A) were placed on the high‐AA diet, and the other group (B) remained on the low‐AA diet. On day 65, the two groups switched diets. On day 115, group B returned to the low‐AA diet. This design, assuming no carryover effect, allowed us to merge the data from the two groups, with the data comparison days being 65 (low‐AA) and 115 (high‐AA) for group B and 130 (low‐AA) and 65 (high‐AA) for group A. The main indices studied were the fatty acid composition of the plasma, red blood cells, platelets, and adipose tissue; in vitro platelet aggregation, bleeding times, clotting factors; immune response as measured by delayed hypersensitivity skin tests, cellular proliferation of peripheral blood mononuclear cells in response to various mitogene and antigens, natural killer cell activity, and response to measles/mumps/rubella and influenza vaccines; the metabolic conversion of deuterated linoleic acid to AA and the metabolic fate of deuterated AA in the subjects on and off the high‐AA diet; and the production of eicosanoids as measured by excretion of 11‐DTXB2 and PGI2‐M in urine. The results of these studies with be presented in the next five papers from this symposium.
The effect of dietary arachidonic acid on plasma lipoprotein distributions, apoproteins, blood lipid levels, and tissue fatty acid composition in humans
Authors: Nelson G. J. , Schmidt P. C. , Bartolini G. , Kelley D. S. , Phinney S. D. , Kyle David , Silbermann Steven , Schaefer Ernst J.
Published: November 2006

Normal healthy male volunteers (n=10) were fed diets (high‐AA) containing 1.7 g/d of arachidonic acid (AA) for 50 d. The control (low‐AA) diet contained 210 mg/d of AA. Dietary AA had no statistically significant effect on the blood cholesterol levels, lipoprotein distribution, or apoprotein levels. Adipose tissue fatty acid composition was not influenced by AA feeding. The plasma total fatty acid composition was markedly enriched in AA after 50 d (P<0.005). The fatty acid composition of plasma lipid fractions, cholesterol esters, triglycerides, free fatty acids, and phospholipid (PL) showed marked differences in the degree of enrichment in AA. The PL plasma fraction from the subjects consuming the low‐AA diet contained 10.3% AA while the subjects who consumed the high‐AA diet had plasma PL fractions containing 19.0% AA. The level of 22:4n‐6 also was different (0.67 to 1.06%) in the plasma PL fraction after 50 d of AA feeding. After consuming the high‐AA diet, the total red blood cell fatty acid composition was significantly enriched in AA which mainly replaced linoleic acid. These results indicate that dietary AA is incorporated into tissue lipids, but selectively into different tissues and lipid classes. Perhaps more importantly, the results demonstrate that dietary AA does not alter blood lipids or lipoprotein levels or have obvious adverse health effects at this level and duration of feeding.
Effects of dietary arachidonic acid on human immune response
Authors: Kelley Darshan S. , Taylor Peter C. , Nelson Gary J. , Schmidt Perla C. , Mackey Bruce E. , Kyle David
Published: November 2006

Arachidonic acid (AA) is a precursor of eicosanoids, which influence human health and the in vitro activity of immune cells. We therefore examined the effects of dietary AA on the immune response (IR) of 10 healthy men living at our metabolic suite for 130 d. All subjects were fed a basal diet containing 27 energy percentage (en%) fat, 57 en% carbohydrate, and 16 en% protein (AA, 200 mg/d) for the first and last 15 d of the study. Additional AA (1.5 g/d) was incorporated into the diet of six men from day 16 to 65 while the remaining four subjects continued to eat the basal diet. The diets of the two groups were crossed‐over from day 66 to 115. In vitro indexes of IR were examined using the blood samples drawn on days 15, 58, 65, 108, 115, and 127. The subjects were immunized with the measles/mumps/rubella vaccine on day 35 and with the influenza vaccine on day 92. Dietary AA did not influence many indexes of IR (peripheral blood mononuclear cell proliferation in response to phytohemagglutinin, Concanavalin A, pokeweed, measles/mumps/rubella, and influenza vaccines prior to immunization, and natural killer cell activity). The postimmunization proliferation in response to influenza vaccine was about fourfold higher in the group receiving high‐AA diet compared to the group receiving low‐AA diet (P=0.02). Analysis of variance of the data pooled from both groups showed that the number of circulating granulocytes was significantly (P=0.03) more when the subjects were fed the high‐AA diet than when they were fed the low‐AA diet. The small increases in granulocyte count and the in vitro proliferation in response to influenza vaccine caused by dietary AA may not be of clinical significance. However, the lack of any adverse effects on IR indicates that supplementation with AA may be done safely when needed for other health reasons.
Age‐related changes in catalytic activity, enzyme mass, mRNA, and subcellular distribution of hepatic neutral cholesterol ester hydrolase in female rats
Authors: Natarajan Ramesh , Ghosh Shobha , McLean Grogan W.
Published: November 2006

Activity and protein mass of hepatic neutral cholesteryl ester hydrolase (CEH) were measured in liver cytosol and washed microsomes of female Sprague‐Dawley rats aged 3, 4, 7, 9, 12, and 16 wk. CEH mRNA was also measured. The microsomal component varied with age and contributed a greater fraction of total activity in females than previously reported in males. Nevertheless, the cytosolic component accounted for 62–80% of activity and 77–94% of immunoreactive protein in postmitochondrial fractions. Cytosolic and microsomal CEH specific activities, relative to total protein, decreased 94 and 83%, respectively, from 3 to 4 wk, prior to onset of puberty at 5 wk, and increased 360 and 137%, respectively, from 12 to 16 wk. These results contrast with an earlier study, in which cytosolic CEH activity of males increased with puberty and declined after 12 wk. Although cytosolic CEH was activated by protein kinase A and inhibited by alkaline phosphatase treatment at all ages, protein kinase activation peaked at 4 wk, coinciding with the initial decrease, in specific activity. Specific activity in cytosol and microsomes correlated with CEH mass at all ages, suggesting that this CEH accounts for most variation in cellular activity. In contrast, CEH mRNA varied little from 3–16 wk, indicating that transcriptional regulation does not make a major contribution to the variation in CEH activity and mass in females, although it may make an important contribution to male‐female differences in CEH expression. Specific activities of cytosolic and microsomal CEH, relative to immunoreactive CEH protein mass, exhibited changes consistent with posttranslational regulation. These results indicate gender‐specific multivalent regulation of hepatic CEH by posttranslational mechanisms during development of female rats.
Biosynthesis of medium‐chain triacylglycerols and phospholipids by HepG‐2 cells
Authors: Pakula Ronit , Rubin Moshe , Moser Asher Moshe , Lichtenberg Dov , Tietz Alisa
Published: November 2006

In an attempt to understand the metabolism by the liver of fatty acids (FA) of different chain length, we have studied the incorporation of [1‐14C]‐labeled C2, C8, C10, C12, and C16 into cellular lipids by HepG‐2 cells. Over 90% of the radiolabeled FA were detected in phospholipids (PL) and triacylglycerols (TAG). The incorporation of C12 and C16 was three to four times higher than that of C8 and C10 (and reached 35 nmoles per mg protein after 1.5 h). The radioactivity of C2, C8, and C10 was recovered mainly in PL. C12 and C16 were incorporated at approximately equal amounts into PL and TAG. The radioactivity of both C2 and C8 was recovered exclusively in long‐chain FA, suggesting oxidation of C8 into C2 units prior to FA synthesis. C10 likewise yielded mainly long‐chain FA. However 10% of unchanged C10 was found in PL and up to 30% in TAG. 14C–C12 was largely incorporated unchanged. Under these conditions, the presence of C10 and C12 in PL and TAG was shown also by gas‐liquid chromatography. In the presence of either C2, C8, or C10, up to 30% of 14C‐monounsaturated FA were detected in PL and TAG. With C12 and C16, the fraction of 14C‐monounsaturated FA was much smaller suggesting that extensive desaturation occurred during de novo synthesis.
Molecular species of phosphoglycerides in liver microsomes of rats fed a fat‐free diet
Authors: Garda Horacio A. , Bernasconi Ana M. , Tricerri M. Alejandra , Brenner Rodolfo R.
Published: November 2006

The influence of a fat‐free diet on the molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) of rat liver microsomes was studied by using reversed‐phase high‐pressure liquid chromatography. In the three phosphoglyceride classes analyzed, the fat‐free diet produced a large decrease in the 18:0/20:4n−6 species but less important changes were found in the 16:0/20:4n−6 species. In PC, the most abundant phosphoglyceride class of rat liver microsomes, the fall in the 18:0/20:4n−6 species was counterbalanced mainly by an enhancement in the 16:0/18:1n−9 species although it was not evident in PE. In PI, the decrease in the 18:0/20:4n−6 species was counterbalanced by an increase in the 18:0/20:3n−9 species. Fluorescence polarization measurements of 1,6‐diphenyl‐1,3,5‐hexatriene in liposomes of 16:0/18:1n−9‐, 18:0/18:1n−9‐, 16:0/20:4n−6‐, and 18:0/20:4n−6‐PC indicated that the change in the saturated fatty acid in the sn‐1 position accompanying the replacement of 20:4n−6 by 18:1n−9 could be very important for a homeoviscous compensation, maintaining the membrane physical properties without large alterations in spite of the essential fatty acid deficiency due to the fat‐free diet.
Lipid peroxidation during n−3 fatty acid and vitamin E supplementation in humans
Authors: Allard Johane P. , Kurian Regina , Aghdassi Elaheh , Muggli Reto , Royall Dawna
Published: November 2006

The purpose of this study was to investigate in healthy humans the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake, alone or in combination with dL‐α‐tocopherol acetate (vitamin E) supplements on lipid peroxidation. Eightly men were randomly assigned in a double‐blind fashion to take daily for 6 wk either menhaden oil (6.26 g, n−3 fatty acids) or olive oil supplements with either vitamin E (900 IU) or its placebo. Antioxidant vitamins, phospholipid composition, malondialdehyde (MDA), and lipid peroxides were measured in the plasma at baseline and week 6. At the same time, breath alkane output was measured. Plasma α‐tocopherol concentration increased in those receiving vitamin E (P<0.0001). In those supplemented with n−3 fatty acids, EPA and DHA increased in plasma phospholipids (P<0.0001) and plasma MDA and lipid peroxides increased (P<0.001 and P<0.05, respectively). Breath alkane output did not change significantly and vitamin E intake did not prevent the increase in lipid peroxidation during menhaden oil supplementation. The results demonstrate that supplementing the diet with n−3 fatty acids resulted in an increase in lipid peroxidation, as measured by plasma MDA release and lipid peroxide products, which was not suppressed by vitamin E supplementation.
The pharmacokinetics of water‐in‐oil‐in‐water‐type multiple emulsion of a new tacrolimus formulation
Authors: Uno Takeji , Yamaguchi Takaji , Li Xiao Kang , Suzuki Yoshinari , Hashimoto Hisakuni , Harada Yukio , Kimura Taizou , Kazui Teruhisa
Published: November 2006

We developed a water‐in‐oil‐in‐water (W/O/W)‐type multiple emulsion of a new tacrolimus formulation. A potential approach to avoid the complications of systemic immunosuppression and simultaneously enhance immunosuppressive efficacy is to deliver immunosuppressive agents locally to the site of the target organs. The W/O/W emulsion is dispersed oil drops containing smaller water droplets that allow the delivery of drugs preferentially to the reticuloendothelial system (RES). Since the liver and the spleen are primary components of the RES, and the brain and the kidney have a poor RES, we hypothesized that a W/O/W emulsion of tacrolimus would prossess the pharmacokinetic benefits of local immunosuppression. We evaluated this hypothesis in a rat model. The tacrolimus levels of whole blood, the liver, spleen, brain, and kidney in rats given intravenous emulsions of tacrolimus (W/O/W group) were compared with a group administered tacrolimus alone (T group). There were no significant differences between the pharmacokinetic parameters of W/O/W group and T group based on whole blood data. However, the W/O/W group had significantly decreased tacrolimus levels in the brain and kidney, and significantly increased levels in the liver and spleen compared with the T group. These data suggest that the W/O/W emulsion is applicable as an intravenous drug carrier for local immunosuppression.
Structure analysis of an allene‐containing estolide tetraester triglyceride in the seed oil of Sebastiana commersoniana (Euphorbiaceae)
Authors: Spitzer Volker , Tomberg Werner , Pohlentz Gottfried
Published: November 2006

The seed oil of Sebastiana commersoniana (Euphorbiaceae) was separated into a triglyceride and an estolide fraction by preparative thin‐layer chromatography. The triglyceride band was characterized by spectroscopic methods, and its fatty acids have been analyzed by gas chromatography (GC) and GC‐mass spectrometry (MS) and their methyl esters. Linolenic acid was the main fatty acid (65%). The estolide band was examined by a combination of spectroscopic and chromatographic methods (ultraviolet, infrared, nuclear magnetic resonance, fast atom bombardment‐MS, GC‐MS of the fatty acids before and after silylation) and was identified as a tetraglyceride, where on α‐carbon of the glyceride backbone was esterfied with 8‐hydroxy‐5,6‐octadienoic acid, which itself was esterfied with trans‐2,cis‐4‐decadienoic acid. The remaining positions of the glyceride backbone were occupied by common fatty acids.
Thermotropic phase behavior of in vivo extracted human stratum corneum lipids
Authors: Bonté Frédéric , Pinguet Patrick , Saunois Alex , Meybeck Alain , Beugin Sophie , Ollivon Michel , Lesieur Sylviane
Published: November 2006

The thermotropic phase behavior of lipids extracted either in vivo from inner forearm (SCLE) or plantar callus (PC) was investigated by differential scanning calorimetry and small angle X‐ray diffraction. PC composition was chromatographically modified (MPC) by eliminating the more polar lipids in order to evaluate their role. Analysis of composition confirms the potential use of PC as a source of stratum corneum lipids. MPC and SCLE exhibit similar differential scanning calorimetry (DSC) profiles with a main transition around 50°C attributed to the solid‐to‐liquid phase transition of the ceramides. The absence of a transition around 50°C for PC suggests the possible perturbation of ceramide packing by the significantly high proportion of phospholipids. X‐ray data suggest a high miscibility of sebum components in stratum corneum lipids with possible modification of chain packing. The MPC patterns show a lipid phase separation which underscores the role of polar lipids in cholesterol/free fatty acids/sterol esters/ceramides structural cohesion.