bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intake of different eicosapentaenoic acid‐containing lipids and fatty acid pattern of plasma lipids in the rats
Authors: Hamazaki Tomohito , Urakaze Masaharu , Makuta Masahiro , Ozawa Akio , Soda Yasuji , Tatsumi Hiroshi , Yano Saburo , Kumagai Akira 
Published: November 2006

AbstractThe ethyl ester of eicosapentaenoic acid (EPA) is the only pure EPA‐containing lipid available in bulk for oral administration. However, there is doubt as to whether EPA ethyl ester can efficiently increase the plasma levels of EPA in comparison with the ability of other kinds of EPA‐containing lipids to do so. Therefore, two other kinds of EPA‐containing lipids were prepared to study the efficiency of oral administration of those lipids for increasing the EPA content in plasma phospholipids and cholesteryl esters. EPA‐containing lipids which were investigated were [A], 1,2,3‐trieicosapentaenoyl‐glycerol, [B] 2‐eicosapentaenoyl‐phosphatidylcholine and [C] ethyl ester of EPA. An adjusted amount of lipids [A], [B] and [C] was administered to rats through a gastric tube for 4 days (the first experiment) or for 10 days (the second experiment), and the fatty acid composition of plasma phospholipids and cholesteryl esters was determined. In the first experiment, there were no significant differences in the efficiency for increasing EPA levels in either phospholipids or cholesteryl esters among the lipids. In the second experiment, the EPA levels of both plasma phospholipids and cholesteryl esters of rats administered ethyl ester of EPA were significantly higher than those of rats administered 2‐eicosapentaenoyl‐phosphatidylcholine. The EPA levels of the rats administered 1,2,3‐trieicosapentaenoylglycerol were between the levels of the two groups mentioned above, but the differences in the EPA levels were not significant. Although an ethyl ester‐type molecule is not a naturally occurring lipid, ethyl ester of EPA is equal to 1,2,3‐trieicosapentaenoyl‐glycerol and appears to be superior to 2‐eicosapentaenoyl‐phosphatidylcholine as to the efficiency for increasing EPA levels in total plasma phospholipids and plasma cholesteryl esters.
L‐carnitine effect on plasma lipoproteins of hyperlipidemic fat‐loaded rats
Authors: Maccari F. , Arseni A. , Chiodi P. , Ramacci M. T. , Angelucci L. , Hulsmann W. C. 
Published: November 2006

AbstractThe effect of oral L‐carnitine administration to rats fed olive oil has been studied. Carnitine significantly decreased triglyceride, cholesterol and phospholipid levels. Particularly, the levels of chylomicron and very low density lipoproteins in the blood were lowered. Low density lipoprotein levels were not affected, and high density lipoproteins were found to be decreased by 20%. Because carnitine did not change the composition of chylomicron and very low density lipoproteins fraction or affect the gastrointestinal triglyceride residue (about 1/3 of the original load), an effect of carnitine on hepatic fatty acid handling is most likely. The lowering of plasma free fatty acid levels by carnitine administration is in favor of an effect of carnitine on fatty acid handling. The effect on the liver is illustrated by the study of acetoacetate formation in in vitro perfused livers from previously olive oil loaded±carnitine‐treated rats. Carnitine pretreatment stimulated ketogenesis. It is speculated that carnitine administration, by promoting β‐oxidation, lowers the production of very low density lipoproteins. This may be accomplished partly by an increase in the hepatic level of fatty acid binding protein, which also has been observed.
Polyunsaturated fatty acids in tissues of rats fed trielaidin and high or low levels of linolenic acid
Authors: Astorg Pierre‐Olivier , Chevalier Joëlle 
Published: November 2006

AbstractMale and female weanling rats that were born to dams fed a diet low in linolenic acid received diets of 15% lipids by weight containing 45% elaidic acid (as trielaidin) and 8.5% or 0.1% linolenic acid for 10 weeks. Four other groups, in which palmitic or oleic acid replaced elaidic acid in the diet, served as controls. The fatty acid profiles of several lipid classes were determined in adipose tissue, adrenals, testes, heart and brain. Elaidic acid was incorporated into tissue lipids in varying degrees, depending on the organ and on the lipid class. Feeding elaidic acid induced no changes in the polyunsaturated fatty acid (PUFA) profiles of testes lipids but resulted in definite modifications of the PUFA patterns of heart phosphatidylcholine (PC) and phosphatidylethanolamine (PE). In linolenic acid‐deprived rats, arachidonic acid was decreased in PC and linoleic acid was increased in both PC and PE; 22∶5n−6 was strongly depressed in both PC and PE. In linolenic acid‐fed rats, 22∶6n−3 was decreased in PC and PE. These changes, on the whole, were more evident in females, and some also were observed in adrenal cholesteryl esters but only slightly in brain phospholipids. the apparent inhibition of the biosynthesis of PUFA induced by dietary elaidic acid appeared to be complex and of greater intensity in the n−6 fatty acid series than in their n−3 homologues.
Effect of marginal zinc deficiency on the apolipoprotein‐B content and size of mesenteric lymph chylomicrons in adult rats
Authors: Koo Sung I. , Lee Christine C. , Norvell John E. 
Published: November 2006

AbstractTo investigate the mechanisms underlining the impaired intestinal absorption of lipids in zinc deficiency, the apo‐B content and chemical composition of chylomicrons from marginally zinc‐deficient rats fed 2.8 ppm of dietary zinc (ZD) were compared with those from pair‐fed (PF) and ad libitum control (CT) groups fed an adequate level (30.8 ppm) of zinc. Chylomicrons, obtained by cannulating the mesenteric lymph, were isolated by ultracentrifugation at 1.3×106 g/min at 12 C and purified by 2% agarose column chromatography. Apolipoprotein‐ (apo) B was separated by the method of isopropanol precipitation. The apo‐B concentration of chylomicrons was lowered significantly in ZD group. The apo‐B contents of chylomicrons in ZD, PF and CT rats, as expressed as % chylomicron protein, were 8.7±0.1, 11.5±0.5 and 10.7±0.7%, respectively. No significant differences were noted between ZD and PF groups in total protein (TP), phospholipid (PL), triglyceride (TG) and cholesterol (CH), although there was a slight decrease in TG and an increase in CH in CT rats compared with ZD and PF groups. The ratio of the core to surface constituents, as determined by TG/(TP+PL), was significantly higher in ZD group relative to the controls, suggesting that chylomicrons from ZD rats were larger. This finding was consistent with the appearance of larger chylomicron particles in the lacteal of the intestinal mucosa following lipid ingestion. These findings suggest that the intestinal synthesis of apo‐B may be defective in zinc‐deficient rats and may explain in part the impaired absorption of dietary lipids observed in zinc deficiency.
Extraction and quantitation of total cholesterol, dolichol and dolichyl phosphate from mammalian liver
Authors: Crick Dean C. , Carroll Kenneth K. 
Published: November 2006

AbstractA procedure is described for the determination of total cholesterol, dolichol and dolichyl phosphate (Dol‐P) in mammalian liver. It is based on extraction of these compounds into diethyl ether after alkaline saponification of the tissue. Extractability is affected by the length of saponification and concentration of potassium hydroxide (KOH) in the saponification mixture. After extraction, total cholesterol and dolichol are quantitated directly by reverse‐phase high pressure liquid chromatography (HPLC) on C18. Dol‐P requires further purification before quantitation by HPLC, this is accomplished by chromatography on silicic acid. These methods gave recoveries of over 90% for cholesterol and dolichol and about 60% for Dol‐P, using [4‐14C]cholesterol, a polyprenol containing 15 isoprene units, and [1‐14C]Dol‐P as recovery standards. Concentrations of total cholesterol, dolichol and Dol‐P in livers from one month‐old‐CBA mice were found to be 5.7±0.7 mg/g, 66.3±1.2 μg/g and 3.7±0.3 μg/g, respectively.
Effects of eicosatetraynoic acid on membrane lipids of trout liver and intestine
Authors: Pelletier X. , Leray C. 
Published: November 2006

AbstractAfter two months feeding either an (n‐3) or an (n‐6) fatty acid‐rich diet, two groups of trout were switched to the (n‐6) or the (n‐3) fatty acid‐rich diet, respectively. Half of each group was treated with 0.03% 5,8,11,14‐eicosatetraynoic acid (ETYA) in the diet. Liver and intestinal brush border membrane lipids were analyzed. No effect was observed on their cholesterol content. ETYA induced an accumulation of 18∶2(n‐6), and it did not affect the 20∶4(n‐6) content but decreased the 22∶5(n‐6) content. ETYA induced an increase of 18∶3(n‐3) content in the brush border membrane and a decrease of the 22∶6(n‐3) content in the liver. Those results suggest that ETYA blocks mainly the Δ6‐desaturase, which should have two different sites in the liver and one in the intestine.
The filamentous fungusmortierella alpina, high in arachidonic acid
Authors: Totani Nagao , Oba Kenkichi 
Published: November 2006

AbstractArachidonic acid is not available readily, although it is widely distributed in animal tissue. We found that in some strains ofMortierella alpina, arachidonic acid accounted for 68.5–78.8% of the total fatty acids. This is more than twice the arachidonic acid content of any organism previously reported. The content of arachidonic acid per dry cell weight was about 25%. Our findings offer a method for the efficient isolation of arachidonic acid in large amounts.
Effect of ethanol on platelet phospholipase A2
Authors: Stubbs Christopher D. , Rubin Raphael 
Published: November 2006

AbstractPlatelet aggregation is known to be inhibited by ethanol, and this has been suggested to be one of the attenuating effects of ethanol in cardiovascular disease. Recent studies have implicated an inhibition of phospholipase A2 induced arachidonic acid release, since the production of prostanoids that are formed from arachidonic acid and are involved in the aggregation process has been shown to be diminished by ethanol. Phospholipase A2 is found in platelets in both a cytosolic form, from where it may translocate to the plasma membrane to release arachidonic acid, and in a secretory form which is released extracellularly upon activition. In the present study, the effect of ethanol on the secretion of phospholipase A2 and on its activity was determined. It was found that ethanol inhibited trast, the activity of the cytosolic form of phospholipase A2 was inhibited by ethanol.
Effects of dietary n−3 fatty acid‐enriched chicken eggs on plasma and tissue cholesterol and fatty acid composition of rats
Authors: Jiang Zhirong , Sim Jeong S. 
Published: November 2006

AbstractThe purpose of this study was to examine the effects of feeding n−3 polyunsaturated fatty acid (PUFA)‐enriched chicken eggs on plasma and liver cholesterol levels and fatty acid composition in rats. Eggs were collected from laying hens fed diets containing 10% flax seed (Hn−3), 12% sunflower seed (Hn−6), or wheat and soybean meal control (CON). Yolk powders were prepared and fed at the 15% level to weanling female Sprague‐Dawley rats for 28 days. Consumption of n−3 PUFA‐enriched yolks significantly reduced both plasma and liver total cholesterol. Liver total lipids and phospholipids of rats fed Hn−3 diet were enriched with linolenic, eicosapentaenoic, and docosahexaenoic acids with a concomitant reduction of arachidonic acid in liver phospholipids. The plasma cholesterol of rats fed yolk powders enriched with n−6 PUFA (mainly linoleic acid) was reduced to the same extent as in those fed the n−3 enriched, but the liver cholesterol was significantly increased, indicating differential effects of dietary n−3 and n−6 PUFA. The results demonstrated that the cholesterolemic and tissue lipid modulating properties of chicken eggs could be modified in a favorable way by altering the fatty acid composition of yolk lipids through manipulation of laying hen diets.
An extended method for separating and quantitating molecular species of phospholipids
Authors: Wiley Margaret G. , Przetakiewicz Marek , Takahashi Mareyuki , Lowenstein John M. 
Published: November 2006

AbstractAN improved and extended method for separating and quantitating molecular species of four phospholipid classes is presented. Crude lipid extract is first separated into phospholipid classes on a silica column. Each phospholipid class is then separated into molecular species without derivatization using high‐performance liquid chromatography on columns packed with octadecyl silica. Quantitation of individual species is achieved by measuring absorbance at 205 nm. Factors for converting absorbancies to mol fractions have been determined. Quantitation by absorbance at 205 nm agrees well with quantitation by gas chromatography which is preferred to quantitation by phosphate analysis. One hundred phospholipid species have been identified. A table of relative retention times of molecular species is provided. Examples of quantitative analyses of species composition are presented.
Incorporation of lipids labeled with various fatty acids into the cytoskeleton of aggregating platelets
Authors: Packham M. A. , Guccione M. A. , Bryant N. L. , Livne A. 
Published: November 2006

AbstractEarlier studies showed that during the first 20 to 25 seconds of aggregation induced by thrombin (0.1 U/mL) or adenosine diphosphate (ADP) (2μM) of rabbit or human platelets prelabeled with [3H]palmitic acid, labeled lipid became associated with the cytoskeleton (isolated after lysis with 1% Triton X‐100, 5 mM EGTA [ethylene glycol‐bis‐(β‐aminoethyl ether(N,N,N′,N′‐tetraacetic acid] in the presence of 0.5 mM leupeptin and 50 mM benzamidine). In comparison with labeled lipid in intact platelets, the labeled lipid that was associated with the cytoskeleton was enriched in phospholipids and ceramide. To determine whether these effects were specific for lipids labeled with palmitic acid, we studied rabbit platelets in which lipids had been labeled by incubation of the platelets with pairs of14C‐ or3H‐labeled palmitic, stearic, arachidonic, and linoleic acids. Examination of the distribution of label among the lipid classes of intact platelets showed that phospholipids contained most of the label. Under the conditions of limited, thrombin‐induced aggregation used, labeled lipids were not lost from the platelets and the distribution of label among the lipid classes was essentially unchanged. There were major differences in the incorporation of labeled lipids into the cytoskeleton. The greatest incorporation (2.1 to 2.8% of the label in the platelets) was observed with palmitic acid‐labeled lipids; by direct comparison, only 44% as much of the label of stearic acid‐labeled lipids, 21% as much of the label of linoleic acid‐labeled lipids, and only 6% as much of the label of arachidonic acid‐labeled lipids was incorporated into the cytoskeleton. Thus the pool of phospholipid that is readily labeled with arachidonic acid appears to be selectively excluded from the cytoskeleton. Also noteworthy is the 4‐ to 5‐fold enrichment of the cytoskeleton with labeled ceramide; an average of 16% of the label from stearic acid in the cytoskeleton was in ceramide. We suggest that ceramide and phospholipids that are readily labeled with saturated fatty acids are selectively incorporated into the cytoskeleton during the early stages of aggregation and may be specifically associated with the points of contact between platelets.
Effect of acylation stimulating protein on the triacylglycerol synthetic pathway of human adipose tissue
Authors: Yasruel Zivart , Cianflone Katherine , Sniderman Allan D. , Rosenbloom Mark , Walsh Mark , Rodriguez Miguel A. 
Published: November 2006

AbstractAcylation stimulating protein (ASP) is a 14 kDa plasma protein which causesin vitro triacylglycerol synthesis in human adipocytes and fibroblasts to increase substantially. ASP was found to stimulate human adipose tissue microsomal glycerophosphate acyltransferase and diacylglycerol acyltransferase activities by 23% and 90%, respectively. However, phosphatidate phosphohydrolase activity showed no increase in activity, nor did microsomal acyl‐CoA synthetase activity. Moreover, ASP did not decrease the apparent Km of diacylglycerol acyltransferase (DGAT), but rather increased its apparent Vmax suggesting direct interaction of ASP with DGAT.
Alterations of hepatic acetyl‐CoA carboxylase by 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin
Authors: McKim J. M. , Marien K. , Schaup H. W. , Selivonchick D. P. 
Published: November 2006

AbstractThe effect of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) on acetyl‐CoA carboxylase (ACC) activity and synthesis was examined. Male Wistar rats received a singlei. p. injection of TCDD (53 μg/kg), and nine days later body weight, liver weight, hepatic lipid, ACC activity and mass were determined and compared to pair‐fed controls. Body weights of TCDD‐treated animals decreased, while liver weights increased resulting in an increase in liver to body weight ratios. ACC activity was decreased by 65%, however sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and Western analysis using a biotin specific probe revealed that ACC protein levels were not appreciably changed. In addition, there was a large increase in exogenous lipid material in TCDD‐treated livers as determined by osmium tetroxide staining. These data suggest that the decrease in ACC activity may be due to direct inhibition of the enzyme by negative allosteric interactions with free fatty acids released from adipose tissue that subsequently accumulate in liver.
Steryl esters in a cell suspension culture of celery (Apium graveolens)
Authors: Dyas Lynne , Prescott Mark C. , Evershed Richard P. , Goad L. John 
Published: November 2006

AbstractArange of analytical techniques was used to investigate the composition of the steryl fatty acyl esters in a cell suspension culture of celery (Apium graveolens). Gas chromatography (GC) and GC‐mass spectrometry (GC‐MS), using electron ionization (EI) and negative ion chemical ionization (NICI), were employed to characterize the intact steryl esters. Assignments were supported by analysis of the sterol and fatty acid moieties released from the intact molecular species by alkaline hydrolysis. A selectivity for sterol esterification was noted, with the major free sterol, stigmasterol, occurring only in a very small amount in the esterified form. Instead, the precursors to Δ5‐phytosterols, particularly cycloartenol, predominated in the ester fraction. The pentacyclic triterpene, β‐amyrin, was also found as the palmitate and linoleate esters. Changes in composition and abundance of the steryl esters during the different growth phases of a celery cell suspension culture were investigated. The total amount of esterified sterols exceeded that of free sterols throughout the growth cycle. The changes observed during growth highlighted differences between the esters of precursor sterols and those of the 4‐desmethyl‐sterols, and it is postulated that the various steryl esters perform different functions in cell metabolism.
Stereospecific analysis of triacyl‐sn‐glycerols by chiral high‐performance liquid chromatography
Authors: Takagi Toru , Ando Yasuhiro 
Published: November 2006

AbstractA method for the stereospecific analysis of triacyl‐sn‐glycerols by high‐performance liquid chromatography (HPLC) on a chiral column is described. Triacyl‐sn‐glycerols were partially degraded with ethyl magnesium bromide, and the monoacylglycerols produced were separated as 1‐ and 2‐monoacylglycerol fractions by thin‐layer chromatography on boric acid‐impregnated silica gel plates. The 1‐monoacylglycerols were resolved intosn‐1 andsn‐3 monoacylglycerol fractions by HPLC on a chiral column (Sumichiral OA‐4100) after derivatization with 3,5‐dinitrophenyl isocyanate. Fatty acid methyl esters obtained from the original triacyl‐sn‐glycerols, 1‐ and 2‐monoacylglycerol fractions, andsn‐1 andsn‐3 monoacylglycerol fractions were analyzed by gas chromatography on open‐tubular columns. Stereospecific acyl distributions in triacyl‐sn‐glycerols were calculated from the data. The acyl distributions of several oils were obtained. The method is rapid, simple and gave reproducible results.
4‐Desmethylsterols from the marine bivalveMacoma balthica
Authors: Jarzebski Andrzej 
Published: November 2006

Abstract4‐Desmethylsterols fromMacoma balthica L. were investigated by gas chromatography and gas chromatography/mass spectrometry after isolation by argentation and column chromatography. Twenty‐three Δ0‐ and Δ5‐sterols with saturated and unsaturated side chains were identified. It is suggested that sterols inM. balthica are derived from dietary sources. The great diversity of minor 4‐desmethylsterols is likely to be due to their role as intermediates in the metabolism of dietary sterols.
Multiple forms of the enzyme glycerophosphodiesterase are present in human brain
Authors: Ross Brian M. , Sherwin Allan L. , Kish Stephen J. 
Published: November 2006

AbstractBrain levels of glycerophosphodiesters, including glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE), are altered in many human central nervous system disorders. Although much information is available on the enzymes responsible for the formation of these phospholipid metabolites, little information is known regarding their catabolism, by glycerophosphodiesterases, in human brain. In both autopsied and biopsied temporal cortex, a phosphocholine‐producing lycerophosphodiesterase activity was observed. In the presence of 1 mM EDTA, the enzyme possessed a pH optimum of 9.0, while the addition of 5 mM zinc acetate shifted the pH optimum to 10.5. When assayed at pH 9.0 in the absence of zinc acetate, the Km and Vmax were 104±2 μM and 77±18 nmol/h/mg protein, respectively, while assaying at pH 10.5 in the presence of 5 mM zinc acetate yielded a Km of 964±56 μM, and a Vmax of 534±114 nmol/h/mg protein. Furthermore, whereas submillimolar concentrations of zinc acetate stimulated the activity of the enzyme in a dose‐dependent manner when assayed at pH 10.5 (EC50=20.3±3.0 μM), this did not result in a reciprocal inhibition of glycerophosphocholine phosphodiesterase (GPC PD) activity when assayed at a more acidic pH. This may suggest that human brain contains two phosphocholine‐producing GPC PD activities, differentiable by their sensitivity to zinc ions. An activity capable of hydrolyzing GPE to form phosphoethanolamine could not be detected in either biopsied or autopsied brain. However, a choline/ethanolamine‐producing glycerophosphodiesterase activity could be readily detected in biopsied, but not autopsied brain. This novel enzyme possessed a neutral pH optimum and was dependent upon divalent cations for activity. In conclusion, human brain contains at least two different glycerophosphodiesterases, a phosphocholine, and a choline/ethanolamine‐producing activity, only one of which can be detected in autopsied tissue. The results of previous studies measuring brain glycerophosphodiesterase activity in degenerative brain conditions may need to be reevaluated in the light of these observations.