bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of rat liver microsomal cholesterol ester hydrolase by reversible phosphorylation
Authors: Martínez María J. , Hernández María L. , Lacort Mercedes , Ochoa Begoña
Published: November 2006

The regulation of neutral cholesterol ester hydrolase activity by changes in its phosphorylation state was studied in rat liver microsomes. Treatment with cAMP‐dependent protein kinase resulted in increased enzyme activity, which was further enhanced by the addition of cAMP and MgATP. Consistent activations were also achieved with MgCl2 and MgATP, the magnesium effect being abolished by ethylenediaminetetraacetic acid and adenosine triphosphate. Cholesterol ester hydrolase was activated twofold by free calcium and Ca2+/calmodulin; this latter effect was blocked by the chelator ethyleneglycol‐bis(β‐aminoethyl ether)N,N,N′,N′‐tetraacetic acid and the calmodulin antagonist trifluoperazine. The phosphatase inhibitors pyrophosphate and glycerophosphate led to marked and dose‐dependent increases in esterase activity, whereas okadaic acid elicited no effect. Furthermore, pyrophosphate and okadaic acid did not change the increases in enzyme activity promoted by Ca2+, Ca2+/calmodulin, Mg2+ and MgATP. Cholesterol ester hydrolase was inactivated in a concentration‐dependent manner by nonspecific alkaline phosphatases. In cAMP‐dependent protein kinase/cAMP‐ or Ca2+/calmodulin‐activated microsomes, a time‐dependent loss of activation in cholesteryl oleate hydrolysis was caused by alkaline phosphatase. These findings suggest that microsomal cholesterol ester hydrolase is activated through cAMP and Ca2+/calmodulin phosphorylation, whereas enzyme deactivation is dependent on phosphatase action.
Biphasic modulation of choline uptake and phosphatidylcholine biosynthesis by vasopressin in rat cardiac myocytes
Authors: Man Adrian S. , Lee Edmund , Choy Patrick C.
Published: November 2006

The effect of vasopressin on choline uptake and phosphatidylcholine biosynthesis in isolated rat heart myocytes was investigated. Myocytes were incubated with labelled choline in the presence of 0.05–1.0 μM vasopressin. Uptake of choline was enhanced (25%) by a low concentration (0.2 μM) of vasopressin, but was attenuated (19%) by a higher vasopressin concentration (1.0 μM). The biosynthesis of phosphatidylcholine was also affected by vasopressin in a biphasic manner. At low concentrations of vasopressin, a general increase in cytosine triphosphate:phosphocholine cytidylyltranferase activity was observed that caused an enhanced conversion of phosphocholine to phosphatidylcholinevia the cytidine diphosphocholine pathway. At high vasopressin concentrations, a decrease in the activity of cytidylyltransferase was detected, which was caused by the translocation of the enzyme from the microsomal fraction to the cytosolic fraction. The decrease in enzyme activity coincides with a reduction in the conversion of labelled phosphocholine to phosphatidylcholine. In view of the fact that phospholipid biosynthesis in rat hepatocytes is inhibited by vasopressin at all concentrations, the biphasic modulation of phosphatidylcholine biosynthesis in rat heart myocytes illustrates the diverse effects of this hormone in different mammalian tissues.
Isolation, characterization and biological activity of inositol sphingophospholipids fromPhytophthora capsici
Authors: Pivot Véronique , Bruneteau Maud , Mas Pierre , Bompeix Gilbert , Michel Georges
Published: November 2006

Several inositol sphingophospholipids (ISPL) were isolated from mycelia ofPhytophthora capsici, a phytopathogenic fungus of pepper (Capsicum annuum c.v. Yolo Wonder). The sphingophospholipids induce a protective response by cotyledons of young peppers against necrotic lesions caused by the pathogenP. capsici. The ISPL structures were determined by chemical methods, fast atom bombardment mass spectrometry and by fast atom bombardment collision‐induced tandem mass spectrometry. All ISPL consisted of ceramides linked to inositol phosphate. The amidelinked fatty acids were found to have 16, 20 and 22 carbon chains. The long chain bases were identified as trimethylsilyl derivatives and shown to be C16‐sphingosine and C16‐dihydrosphingosine. The protective effect of the ISPL on cotyledons of young peppers against necrotic lesions caused by the pathogenP. capsici was shown not to be dependent on the unsaturation of the C16‐sphingosine base and the nature of the acyl chain. We also investigated the effect of growth conditions on the ISPL produced in three different, chemically defined media that are commonly used for fungi cultures. We showed thatP. capsici synthesized one major class of compounds with molecular weights of Mr=833 and 835 containing the 16∶1 base and the 22∶1 or the 22∶0N‐acyl group, independent of the growth medium used. The presence of phosphite or fosetyl‐A1 did not affect the result.
Interaction of dietary fatty acids and cyclosporine a in the borderline hypertensive rat: Tissue fatty acids
Authors: Mills David E. , de Antueno Roberto , Scholey James
Published: November 2006

In this study we examined (i) the effects of cyclosporine A (CS) on tissue lipid composition and (ii) the effect of changes in dietary n−6 fatty acids on tissue responses to CS. Fatty acid composition of liver, kidney, heart and brain were determined after 4 wk of treatment with CS (10 mg/kg·d p.o.) in male borderline hypertensive rats (BHR, n=4/group), whose diet was supplemented with either safflower oil or evening primrose oil (EPO). Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine/phosphatidylinositol, triglyceride and cholesteryl ester fatty acids were measured in kidney, heart, brain and liver. The same parameters were also measured in safflower‐fed BHR (n=4) receiving placebo. The effects of CS on liver microsomal Δ9, Δ6 and Δ5 desaturasesin vitro were also followed. CS affected the fatty acid composition of all tissues examined, with the greatest changes seen in the renal phosphatidylcholine and phosphatidylserine/phosphatidylinositol fractions. All CS‐induced changes that occurred in the liver, brain and renal fatty acids were reversed by EPO. CS elevated Δ9 desaturase but had no effect on Δ6 and Δ5 desaturase. In light of (i) the observation that EPO normalizes renal function and blood pressure in CS‐treated BHR, and (ii) the importance of the kidney in blood pressure regulation, the data suggest that the beneficial effects of EPO on CS toxicity may involve changes in renal phospholipid fatty acid profiles.
Effects of dietary protein and cholesterol on phosphatidylcholine and phosphatidylethanolamine molecular species in mouse liver
Authors: Koba Kazunori , Rozee Linda A. , Horrobin David F. , Huang Yung‐Sheng
Published: November 2006

The present study examined the effects of two atherogenic factors, animal protein and cholesterol, on the distribution of fatty acids and the molecular species of major liver phospholipids in mice. Weanling mice were fed a semisynthetic diet supplemented with either casein or soy protein (20%, w/w) in the presence or absence of 0.5% cholesterol for 4 wk. Results from mouse liver showed that animal protein and, more so, dietary cholesterol modified the fatty acid profiles of the phospholipids. Animal protein had no significant effect on the concentration of lipids, but it altered the relative distribution and fatty acid profiles of the phospholipids, phosphatidylcholine and phosphatidylethanolamine. Dietary cholesterol, on the other hand, significantly increased the concentration of liver lipids, but it did not alter the relative distribution of phosphatidylcholine and phosphatidylethanolamine. In cholesterol‐fed mice, the proportions of molecular species containing 18∶2n−6 were increased, whereas those containing 20∶4n−6 were decreased, indicating that dietary cholesterol suppressed linoleic acid metabolism. Since cholesterol feeding selectively decreased the ratio of 18∶0/20∶4n−6 in phosphatidylcholine, whereas it increased the 18∶0/18∶2n−6 ratio in phosphatidylethanolamine, this finding suggests that dietary cholesterol may affect the incorporation of fatty acids but not the rate of synthesis of phosphatidylcholine and phosphatidylethanolamine.
Effect of dietary fish oil on blood levels of free fatty acids, ketone bodies and triacylglycerol in humans
Authors: Dagnelie Pieter C. , Rietveld Trinette , Swart G. Roelof , Stijnen Theo
Published: November 2006

Although the reduction of serum triacylglycerol concentrations by dietary fish oil is a well‐known effect, the exact mechanism of this effect has not been previously studied in human subjects. Therefore, the aim of this study was (i) to examine the effect of short‐term fish oil supplementation on blood concentrations of ketone bodies, free fatty acids and triacylglycerol in healthy humans and (ii) to verify whether the observed relationships between these variables would be consistent with reduced lipolysis and/or enhanced hepatic fatty acid oxidation after fish oil supplementation. Twenty subjects (21–23 years, normal liver function tests) were randomly divided into two groups to supplement their usual diet with either 30 g/d of fish oil (n=11) or olive oil (n=9). Venous blood samples were drawn after an overnight fast, before and after 1, 3 and 7 d of fish oil/olive oil supplementation. Blood concentrations of triacylglycerol and free fatty acids decreased consistently after fish oil supplementation; the reduction was already significant after one day of fish oil (P<0.001 for triacylglycerol andP=0.01 for free fatty acids). In contrast, neither of these blood values changed after olive oil supplementation (P>0.10). No significant changes in glucose, insulin or ketone body levels were observed in either group after supplementation. After fish oil, but not after olive oil supplementation, the ratio of blood ketone body levels to free fatty acid levels increased significantly (P<0.05). Furthermore, after fish oil supplementation only, free fatty acid levels were significantly correlated with levels of ketone bodies (day 7 of supplementation: r=0.90,P<0.001) and triacylglycerol (maximum value on day 3: r=0.77,P<0.01). These findings suggest that reduced lipolysis and increased hepatic β‐oxidation/ketogenesis may contribute to reduced triacylglycerol levels after ω3 fatty acid supplementation in humans. Turnover studies are needed in order to further quantitate these processes.
Lipid peroxidation and antioxidant status is affected by different vitamin E levels when feeding fish oil
Authors: Cho Sung‐Hee , Choi Young‐sun
Published: November 2006

The protective role of vitamin E and changes in the status of several physiological antioxidants after feeding rats a fish oil diet were investigated. Six‐week‐old male Sprague‐Dawley rats were divided into four groups and fed experimental diets for 8 wk. Three fish oil (FO) groups were fed a menhaden fish oil and soybean oil (SO) (9∶1) mixture as 10% (w/w) of the diet. These groups were provided with ≤3, 45 or 209 IU of vitamin E/kg diet. One SO group was used as control and was fed ≤45 IU of vitamin E/kg diet. Plasma vitamin E levels, when expressed as vitamin E per mL plasma, were extremely low in the group fed FO and ≤3 IU of vitamin E, and were lower in the groups fed FO than in the group fed SO. However, plasma vitamin E levels when expressed per mg plasma lipid were higher in the FO groups provided with ≤45 and 209 IU of vitamin E than in the SO group. Compared with the SO group, plasma levels of thiobarbituric acid reactive substances (TBARS), when expressed per mg lipid, were higher in the three FO groups, plasma retinol levels were lower in the FO groups provided with ≤3 and 45 IU of vitamin E, and ascorbic acid levels were lower only in the FO group provided with ≤3 IU of vitamin E. Blood glutathione (GSH) levels were lower in all three FO groups than in the SO group. Liver vitamin E levels increased as the dietary level of vitamin E increased, but all FO groups had higher liver levels of TBARS than the SO group. The dietary vitamin E levels were correlated positively with plasma vitamin E (r=0.71) and negatively with TBARS in both the plasma and liver of rats fed FO. Among the antioxidants measured, correlations were found between plasma retinol and vitamin C (r=0.64), and plasma vitamin C, uric acid (r=0.72) and blood GSH (r=0.60). Weaker correlations were found between plasma retinol, uric acid and blood GSH. It is concluded that vitamin E requirements are higher when feeding fish oil. Vitamin E seems necessary to prevent enhanced lipid peroxidation and to maintain appropriate levels of other physiological antioxidants.
Effects of high corn oil diet on preneoplastic murine colons: Prostanoid production and lipid composition
Authors: Robblee Nancy M. , Bird Ranjana P.
Published: November 2006

In the present study, the effect of normal (5% by wt) and high (23.5% by wt) corn oil diets on prostanoid production and on the lipid composition of preneoplastic colonic epithelium was investigated. CF1 mice (female, 3–4‐weeks‐old) were fed a normal corn oil dietad libitum and were treated with the colon carcinogen 1,2‐dimethylhydrazine (DMH, 20 mg/kg/wk) or saline (control) for 24 wk. At this stage, all animals received the AIN‐76 diet (normal corn oil)ad libitum. Following the last injection, half of the animals from each treatment group were randomly allocated to a high corn oil diet for 5 to 10 wk, whereas the remaining animals continued on the normal corn oil diet. After 5 wk of feeding, the colonic mucosa of carcinogentreated animals had a higher level of bicyclic prostaglandin E2 (PGE2) than had the animals in the control groups; prostanoid synthesis in the colonic mucosa of control animals was unaffected by the high corn oil diet. Preneoplastic colonic mucosa of animals fed the high corn oil diet had a significantly higher level of PGE2 than corresponding control colonic mucosa. The 6‐keto‐prostaglandin F1α/thromboxane B2 ratio was significantly lower in the DMH‐treated groups than in the control groups, and was unaffected by dietary treatments. After 10 wk of feeding a particular diet, the differences in the fatty acid composition between the control and DMH‐treated groups were minor. Our findings demonstrate that the preneoplastic colonic epithelium differs from that of normal epithelium with respect to prostanoid synthesis.
Famesylamine: An inhibitor of famesylation and growth ofras‐transformed cells
Authors: Kothapalli Ravi , Guthrie Najla , Chambers Ann F. , Carroll Kenneth K.
Published: November 2006

Farnesylamine, an analogue of farnesol, was shown to inhibit growth of PAP2 cells (ras‐transformed NIH 3T3 cells) in a dose‐dependent manner. This inhibition was overcome by adding farnesol to the culture medium, but not by adding geranylgeraniol, squalene, cholesterol, dolichol, myristic acid or palmitic acid. Farnesylamine inhibited both farnesyl/protein transferase and geranylgeranyl/protein transferase in whole cell extracts and also inhibited the prenylation of proteins, particularlyras p21, in PAP2 cells. Inhibition of prenylation was associated with increased biosynthesis of other products of the mevalonate biosynthetic pathway. These observations suggest that inhibition of the growth of PAP2 cells by farnesylamine may be due to blocking ofras‐mediated signal transduction. This offers a means of investigating mechanisms involved inras action and raises the possibility of developing novel strategies for anticancer therapy.
Different resistance of mammalian red blood cells to hemolysis by bile salts
Authors: Salvioli G. , Gaetti E. , Panini R. , Lugli R. , Pradelli J. M.
Published: November 2006

To evaluate why hemolysis of red blood cells (RBC) by bile acids varies in different mammalian species, we determined the mean corpuscular volume (MCV), lipid content and the concentrations of the conjugates of deoxycholate and of NaCl inducing 50% hemolysis of RBC from healthy humans, pigs, horses, cows, sheep and jaundiced humans. A volume of 0.05 mL of washed RBC at 1% hematocrit, which has the same lipid content but different phospholipid composition and number of erythrocytes (owing to the variable MCV), was incubated in taurodeoxycholate (TDC) solution (0–5 mM) to determine the TDC concentration inducing 50% hemolysis (TDC50). The TDC50 was highest in RBC of sheep and decreased within the series sheep>pig>cow>horse>healthy human>jaundiced human, which have generally increasing MCV. The osmotic resistance followed an inverse order, with jaundiced human >healthy human>horse>cow>pig>sheep. Although we found no correlation between the TDC50 and phospholipid composition of the erythrocytes tested, the extent of bile salt‐induced hemolysis seemed to depend on both the MCV and the number of erythrocytes in the incubation medium.
Fatty acid content and composition ofOenothera hookeri seeds containing mutant plastids
Authors: Epp Melvin D. , Pollard Michael R.
Published: November 2006

The effects of plastid mutations on seed oil content and fatty acid composition are of considerable interest. Seeds of a number of plastome mutants produced by thepm plastome mutator line ofOenothera hookeri were therefore harvested to investigate these effects. The mutants were altered solely in their plastome: each seed lot had the same nuclear background. To facilitate the study, a rapid single‐step method was developed to simultaneously assay both oil content and fatty acid composition of small quantities ofOenothera seed. The lipid analyses showed that the mutated plastome often changed the oil content of the seeds, and that such changes always reduced oil content. Strong negative correlations were observed between oil content and palmitate or γ‐linolenate, and a strong positive correlation was observed between oil content and linoleate. This is the first instance to our knowledge in which plastid mutations have been unequivocally demonstrated to affect seed oil content and composition. Such effects would be indirect, since the mutated plastid genes would not be the structural genes for enzymes on the pathway of oil biosynthesis. The plastid mutations demonstrate another layer of potential complexity in understanding oilseed genetics.
Isolation of brominated long‐chain fatty acids from the phospholipids of the tropical marine spongeAmphimedon terpenensis
Authors: Garson Mary J. , Zimmermann Mary P. , Hoberg Max , Larsen Rundi M. , Battershill Christopher N. , Murphy Peter T.
Published: November 2006

Preliminary investigation of the phospholipid fatty acid composition of the tropical marine spongeAmphimedon terpenensis by gas chromatography/mass spectrometry revealed the presence of some novel brominated fatty acids. Two new brominated fatty acids, (5E, 9Z)‐6‐bromo‐5,9‐tetracosadienoic acid (2a) and (5E, 9Z)‐6‐bromo‐5,9‐pentacosadienoic acid (3a) were subsequently isolated from a chloroform/methanol (3∶1, vol/vol) extract of the sponge and characterized as their methyl esters 2b and 3b. The known brominated fatty acid (5E, 9Z)‐6‐bromo‐5,9‐hexacosadienoic acid (4a) was also isolated. The new fatty acid methyl esters were confirmed as brominated δ5,9 acid derivatives by chemical ionization mass spectrometry. The position of the bromine substituent was determined to be C‐6 by nuclear magnetic resonance techniques while the stereochemistry of the two double bonds was deduced by nuclear Overhauser enhancement difference spectroscopy. The biosynthetic implications of the co‐occurrence of the three brominated acids are discussed.
Oxidations of the α‐tocopherol model compound 2,2,5,7,8‐pentamethyl‐6‐chromanol. Formation of 2,2,7,8‐tetramethylchroman‐5,6‐dione
Authors: Kohar Indrajati , Suarna Cacang , Southwell‐Keely Peter T.
Published: November 2006

Overoxidation of α‐tocopherol (1a) by silver nitrate produces tocored (9a) as a major product. The aim of the present work was to elucidate the pathway of formation of tocored using the α‐tocopherol model compound, 2,2,5,7,8‐pentamethyl‐6‐chromanol (1b). Oxidation of 1b by silver nitrate in ethanol produces 2‐(3‐hydroxy‐3‐methylbutyl)‐3,5,6‐trimethyl‐1,4‐benzoquinone (6b) and 2,2,7,8‐tetramethylchroman‐5,6‐dione (9b, the model compound of tocored) as major products. Formation of 6b is rapid and is accompanied by an equally rapid fall in pH. Formation of 9b only occurs after 6b has reached maximum concentration and has begun to decline. It appears that acid promotes the dehydration and recyclization of 6b into a quinone methide (2b), which is then rehydrated into 5‐hydroxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanol (5b), the phenolic isomer of the quinone 6b. Oxidative deformylation of 5b leads to 9b. It is also demonstrated that 6b, heated in ethanol in the presence of acid and in the absence of any oxidizing agent, is converted into 9b, 1b, 5‐ethoxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanol (4b) and 2‐(3‐hydroxy‐3‐methylbutyl)‐3‐ethoxymethyl‐5,6‐dimethyl‐1,4‐benzoquinone (7b). It seems that dehydration and recyclization of 6b into 5b occurs as above and that 6b then oxidizes 5b into 9b, while being reduced into the hydroquinone of 6b (6bH2). Compound 6bH2 then cyclizes in acid to 1b. A possible alternative pathway from 6b to 9b that does not involve 5b is also discussed. These results suggest that 6b and, by implication, α‐tocopheryl quinone (6a), is not a stable compound and, in the presence of acid, is readily oxidized to 9b.
Synthesis and antitumor activity of 1‐β‐D‐arabinofuranosylcytosine conjugates of optical isomers of ether and thioether lipids
Authors: Hong Chung , An Seung‐Ho , Nechaev Alexander , Kirisits Alan J. , Vig Rakesh , West Charles R.
Published: November 2006

Four 1‐β‐D‐arabinofuranosylcytosine conjugates (ara‐C) (1a, b and 2a, b) ofsn−1 andsn−3 isomers of 1‐O‐octadecyl‐2‐O‐palmitoylglycerol and its 1‐S‐alkyl analogue have been synthesized, and their antitumor activity against L1210 lymphoid leukemia in mice were compared with those of the previous conjugates (3a, b) of racemates in order to determine the significance of chirality of the glycerol moieties for activity. Administration (i.p.) of a single dose (300 mg/kg) of conjugates ofsn−1 (1a),sn−3 (2a) andrac (3a) isomers of the ether lipid increased lifespan of i.p. implanted L1210 lymphoid leukemic DBA/2J mice by 169, 175 and 236%, respectively. Thesn−1 (1b),sn−3 (2b), andrac (3b) isomers of the thioether lipid with a single dose of 300 mg/kg produced an increase in lifespan values of 238, 263 and 250%, respectively. The results indicate that chirality of the glycerol moieties appears not to be critical for the activity, and racemates 3a and 3b are promising prodrugs of ara‐C for further clinical investigations.
Application of paired‐ion high‐performance liquid chromatography to the separation of molecular species of phosphatidylinositol
Authors: Nakagawa Yasuhito
Published: November 2006

A paired‐ion high‐performance liquid chromatographic (HPLC) procedure was developed for the separation of individual molecular species of phosphatidylinositol (PI) without prior derivatization. The separation is accomplished on a reverse‐phase column using acetonitrile, methanol and 10 mM tetrabutylammonium phosphate as mobile phase. Separation of the major molecular species of soybean PI by HPLC is achieved within 60 min. The method is applicable to analytical and metabolic studies on PI and has the advantage that the entire PI structure is preserved, as no degradation or derivatization procedures are involved.
Separation and identification of isomeric conjugated fatty acids by high‐performance liquid chromatography with photodiode array detection
Authors: Husain Sajid , Devi K. Sita
Published: November 2006

A simple, high‐performance liquid chromatographic method is described for the separation of tetraenoic, trienoic and dienoic conjugated fatty acids on a Zorbax ODS reversed‐phase column using acetonitrile/tetrahydrofuran (95∶5, vol/vol) at a flow rate of 1.2 mL/min as mobile phase. Also described is the separation of the isomeric conjugated fatty acids with acetonitrile/water/tetrahydrofuran (90∶90∶1, by vol) as mobile phase. The simultaneous detection and identification of the separated geometrical isomers in the eluant was accomplished using photodiode array detection.
Reevaluation of the neutral lipids ofTilletia controversa andTilletia tritici
Authors: Beattie S. E. , Stafford A. E. , King A. D.
Published: November 2006

Differential scanning calorimetry of whole teliospores and lipid extracts ofTilletia controversa Kühn andT. tritica Tul. indicated that the lipid composition of teliospores was different than earlier reported. An exothermic peak at −40 to −45°C and an endotherm at −25 to −15°C indicated that the majority of lipids were triacylglycerols (TAG). Hot isopropanol was used to inactivate lipases during lipid extraction. Thin‐layer chromatographic analysis of extracted lipids showed that free fatty acids (FFA) were not present in great quantities unless water was present during lipid extraction. As measured by gas chromatography. FFA accounted for 1–5% of the lipid content in teliospores ofTilletia spp. The TAG content of teliospores was 60–80% of total lipids.
The effect of dietary n−3 polyunsaturated fatty acids on HDL cholesterol in Chukot residentsvsmuscovites
Authors: Gerasimova E. , Perova N. , Ozerova I. , Polessky V. , Metelskaya V. , Sherbakova I. , Levachev M. , Kulakova S. , Nikitin Yu. , Astakhova T.
Published: November 2006

Native Chukot Peninsula residents, in contrast to Muscovites, consume a diet rich in n−3 polyunsaturated fatty acids. This dietary peculiarity is reflected in differences in plasma lipid and apolipoprotein contents. The Chukot residents have lower contents of total cholesterol, triglyceride, LDL (low density lipoprotein) cholesterol and apolipoprotein B, but higher HDL (high density lipoprotein) cholesterol levels than do Muscovites. The apolipoprotein A‐I levels were identical in both groups. A higher HDL cholesterol to apolipoprotein A‐I ratio was determined in the coastline Chukot residents (0.52±0.01) than in Muscovites (0.43±0.01; p<0.01). In contrast to Muscovites, the coastline Chukot residents also had higher n−3 and lower n−6 polyunsaturated fatty acid percentages in plasma and erythrocyte lipids, and lower phosphatidylcholine and higher sphingomyelin or phosphatidylethanolamine levels in HDL2band HDL3. The higher HDL cholesterol levels in the plasma of the coastline Chukot residents appears to reflect the higher cholesterol‐scavenging capacity of their HDL.

We conclude from this study that the regular consumption of dietary n−3 polyunsaturated fatty acids by the coastline Chukot residents decreased LDL cholesterol transfer from plasma to peripheral cells, and enhanced cholesterol efflux from cellular membranes toward HDL.
Eicosapentaenoic acid inhibits tube formation of vascular endothelial cellsin vitro
Authors: Kanayasu Toshie , Morita Ikuo , Nakao‐Hayashi Junko , Asuwa Noriko , Fujisawa Chiho , Ishii Toshiharu , Ito Hideki , Murota Sei‐itsu
Published: November 2006

We previously have described a quantitative angiogenesisin vitro model, in which endothelial cells are cultured between two layers of type I collagen gel and become organized into tube‐like structures. Using this model, the effect of eicosapentaenoic acid (20∶5n−3) on tube formation was investigated. When the endothelial cells isolated from bovine carotid artery were treated for 2 days with 5 μg/mL of arachidonic acid (20∶4n−6), eicosapentaenoic acid or docosahexaenoic acid (22∶6n−3), these polyunsaturated fatty acids were extensively incorporated into cellular phospholipids. The content of arachidonic, eicosapentaenoic and docosahexaenoic acid increased from 9.58% to 23.29%, from 0.98% to 11.76% and from 6.88% to 18.40%, respectively. When the eicosapentaenoic acid‐treated cells were cultured between collagen gels, the tube‐forming ability of the cells was markedly inhibited. The inhibition was dose‐dependent between 1.0 and 5.0 μg/mL of eicosapentaenoic acid. At 5.0 μg/mL of eicosapentaenoic acid the inhibition reached 76%. By contrast, arachidonic acid increased tube formation, and docosahexaenoic acid had no effect. To elucidate the mechanism of eicosapentaenoic acid induced inhibition ofin vitro tube formation, we examined the effect of the acid on the proliferation of endothelial cells. Eicosapentaenoic acid at any dose (<5.0 μg/mL) had no effect on the proliferation of endothelial cells cultured on plastic plates without collagen gel. However, when the cells were cultured between collagen gels, eicosapentaenoic acid inhibited cell growth in a dose‐dependent manner with maximum inhibition being observed at 2.5 μg/mL. These data suggest that eicosapentaenoic acid suppresses tube formation of endothelial cells, at least in part,via its inhibitory effect on cellular proliferation. Thus eicosapentaenoic acid may act as an endogenous inhibitor of angiogenesis under various pathological conditions, including tumor growth and chronic inflammation.
Preparation of methyl 11,14,17‐eicosatrienoate‐8,8,9,9‐d4 and methyl 8,11,14,17‐eicosatetraenoate‐8,9‐d2
Authors: Rakoff Henry
Published: November 2006

Methyl 11,14,17‐eicosatrienoate‐8,8,9,9‐d4 was obtained by Wittig coupling of 3,6‐nonadienyltriphenylphosphonium iodide with methyl 11‐oxoundecanoate‐8,8,9,9‐d4. For the synthesis of the phosphonium salt, 2‐pentynol was converted to 1‐bromo‐2‐pentyne with triphenylphosphine dibromide. Grignard coupling of 1‐bromo‐2‐pentyne with 3‐butynol in the presence of cuprous chloride gave 3,6‐nonadiynol. The latter was hydrogenated in the presence of P‐2 nickel catalyst to yield 3,6‐nonadienol. The dienol was convertedvia the bromide and iodide to the phosphonium salt. The aldehyde ester was prepared starting with the coupling of 7‐bromoheptanoic acid and 3‐butynol with lithium amide in liquid ammonia. The hydroxyalkynoic acid obtained was converted to the methyl ester and the hydroxy group was converted to the tetrahydropyranyloxy group. Subsequent deuteration of the methyl 11‐(2‐tetrahydropyranyloxy)‐8‐undecynoate with deuterium gas andtris‐(triphenylphosphine)chlorohodium gave the corresponding tetradeuterated product. The tetrahydropyranyl group was removed and the methyl 11‐hydroxy‐undecanoate‐8,8,9,9‐d4 was oxidized to the aldehyde ester with pyridinium chlorochromate. Methyl 8,11,14,17‐eicosatetraenoate‐8,9‐d2 was obtained by a similar sequence of reactions. The methyl 11‐oxo‐8‐undecenoate‐8,9‐d2 required for the Wittig coupling was obtained by Lindlar deuteration of the protected alkynoic ester to methyl 11‐(2‐tetrahydropyranyloxy)‐8‐undecenoate‐8,9d2. The unsaturated hydroxy ester was oxidized to the aldehyde ester by periodinane with negligible isomerization. The allcis isomers were isolated by silver resin chromatography.
Reactions of dinitrogen pentoxide and nitrogen dioxide with 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine
Authors: Lai C. C. , Finlayson‐Pitts B. J.
Published: November 2006

The reactions of gaseous dinitrogen pentoxide (N2O5) and nitrogen dioxide (NO2) with 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) coated on the inside surface of a glass reaction cell were studied at 298 K. Unsaturated phosphatidylcholines are significant components of pulmonary surfactant in the alveolar region of the lung and hence serve as a simple model to examine reactions of pulmonary surfactant with these oxidant air pollutants. Using high‐performance liquid chromatography (HPLC), Fourier transform infrared and fast atom bombardment mass spectroscopy, the major products of reactions of POPC with N2O5 and NO2 were separated and identified. In the POPC‐N2O5 reaction using either air or helium as a buffer gas, the nitronitrate, vinyl nitro and allylic nitro derivatives, as well as a small amount of thetrans‐isomer of the starting material, were obtained. The nature of the products obtained from the POPC‐NO2 reaction depends on the concentration of NO2 as well as whether air is present. At low NO2 concentrations (PNO2/N2O4≤3.8 Torr) in air or in helium, thetrans‐isomer of POPC was formed almost exclusively. At higher NO2 concentrations (PNO2/N2O4≥20 Torr) in helium, the dinitro, vinyl nitro and nitro alcohol derivatives were formed. In the presence of air (or 24%18O2 in helium), a nitronitrate and a dinitronitrate were additional products. Mechanisms for the formation of the observed products and implications for the inhalation of oxides of nitrogen are discussed.
Determination of phospholipase D‐mediated hydrolysis of phosphatidylethanolamine
Authors: Kiss Zoltan
Published: November 2006

While phospholipase D‐mediated hydrolysis of phosphatidylcholine is well documented, we have recently shown that phospholipase D‐mediated hydrolysis of phosphatidylethanolamine (PtdEtn) [Kiss, Z., and Anderson, W.B.,J. Biol. Chem. 264, 1483–1487 (1989);J. Biol. Chem. 265, 7345–7350 (1990)] is equally prominent. This made it necessary to define in detail the conditions required for the detection of agonist‐stimulated PtdEtn hydrolysis. Using the [14C]ethanolamine‐prelabeled rat‐1 fibroblast model and 12‐O‐tetradecanoylphorbor 13‐acetate (TPA) as a model compound with the known ability to stimulate phospholipase D, we demonstrated that optimal detection of TPA‐induced ethanolamine release requires i) fractionation of water‐soluble ethanolamine products; ii) addition of unlabeled ethanolamine to quench the phosphorylation of newly formed [14C]ethanolamine; and/or iii) prolonged preincubation of prelabeled cells in an isotope‐free medium before the addition of TPA. This preincubation step reduces the cellular content of unincorporated14C‐labeled ethanolamine metabolites and improves the signal‐to‐noise ratio.
Synthesis of a phosphatidyl derivative of vitamin E and its antioxidant activity in phospholipid bilayers
Authors: Koga Takuro , Nagao Akihiko , Terao Junji , Sawada Kohei , Mukai Kazuo
Published: November 2006

A novel phospholipid containing a chromanol structure at its polar head group was synthesized from egg yolk phosphatidylcholine and 2,5,7,8‐tetramethyl‐6‐hydroxy‐2‐(hydroxyethyl)chroman by transphosphatidylation catalyzed by phospholipase D fromStreptomyces lydicus. The structure of the product synthesized was shown by spectral analysis to be 1,2‐diacyl‐sn‐glycero‐3‐phospho‐2′‐hydroxyethyl‐2′ 5′,7′,8′‐tetramethyl‐6′‐hydroxychroman. The phosphatidylchromanol (PCh) showed antioxidant activity against radical chain oxidation of methyl linoleate in solution in a manner similar to that ofd‐α‐tocopherol (α‐Toc) and 2,2,5,7,8‐pentamethyl‐6‐chromanol. However, PCh was less effective as a chain‐breaking antioxidant than was α‐Toc when unilamellar egg yolk phosphatidylcholine liposomes were exposed to either a water‐soluble or a lipid‐soluble radical initiator. It is likely that the phospholipid nature of PCh affects the location and the mobility of the chromanol moiety in the membrane bilayer resulting in a decrease in antioxidant activity. On the other hand, the antioxidant activity of PCh was little different from that of α‐Toc in unilamellar liposomes when exposed to a lipid‐soluble radical initiator in the presence of ascorbic acid. It appears that PCh in phospholipid bilayers can be regenerated by ascorbic acid in aqueous phase as can be α‐Toc. The new phospholipid, phosphatidylchromanol, should prove useful as a chain‐breaking antioxidant in phospholipid membranes.
Butylated hydroxyanisole inhibits tumor necrosis factor‐induced cytotoxicity and arachidonic acid release
Authors: Brekke Ole‐Lars , Espevik Terje , Bjerve Kristian S.
Published: November 2006

The mechanisms by which the antioxidant butylated hydroxyanisole (BHA) inhibits recombinant tumor necrosis factor alpha (rTNF‐α)‐induced cytotoxicity have been studied in WEHI 164 clone 13 (WEHI) and L929 fibrosarcoma cells. When BHA was added simultaneously with rTNF‐α, it completely inhibited rTNF‐α cytotoxicity in the WEHI and L929 cells. BHA also inhibited the toxicity when added 2 h after rTNF‐α in WEHI cells, suggesting that BHA inhibits some late intracellular event(s) in rTNF‐α cytotoxicity. Pretreating WEHI cells with BHA for 4 h did not decrease the binding of rTNF‐α to its receptors as measured using flow cytometry. BHA inhibited rTNF‐α toxicity in the presence of actinomycin D and cycloheximide, indicating that neither mRNA nor protein synthesis is necessary for the BHA effect. The antioxidant butylated hydroxytoluene (BHT) and indomethacin did not inhibit the rTNF‐α‐induced cytotoxicity nor the rTNF‐α‐induced release of [3H]arachidonic acid. By comparison, BHA completely inhibited the rTNF‐α‐induced release of arachidonic acid, suggesting that BHA somehow inhibits rTNF‐α‐induced activation of phospholipase(s). In WEHI cells, rTNF‐α increased the level of protein‐associated thiobarbituric acid reactive substances (TBARS) dose‐dependently. BHA, but not BHT, blocked rTNF‐α‐induced cytotoxicity and rTNF‐α‐induced accumulation of protein‐associated TBARS, suggesting that rTNF‐α cytotoxicity is correlated with protein‐associated TBARS. In conclusion, the results suggest that BHA blocks some post receptor event in rTNF‐α‐induced cytotoxicity, and that activation of phospholipase(s) coupled with the enzymatic formation of specific oxidized lipids could be a pivotal event in rTNF‐α‐induced cytotoxicity.
Mass determination of the fatty acids released from tannin‐stimulated rabbit alveolar macrophages
Authors: Ralston Nicholas V. C. , Rohrbach Michael S.
Published: November 2006

Previous studies with macrophages that had been prelabeled with [14C]arachidonic acid (20∶4) have shown that condensed tannin is a potent agonist for the release of arachidonic acid. However, it has not been demonstrated that the percentage release of [14C]20∶4 accurately reflects the metabolic activity of the endogenous 20∶4 pool. In order to measure the 20∶4 mass release relative to the total cellular 20∶4 pool, the free fatty acids of freshly isolated alveolar macrophages were derivatized with a fluorescent reagent, and then separated and quantified by high‐performance liquid chromatography. The amounts of esterified fatty acids were measured by gas chromatography of the methyl esters. Free fatty acid levels were compared to those of the total esterified plus unesterified fatty acids to determine the actual percentage released of each fatty acid. Tannin‐stimulated release of 20∶4 mass reflected that previously reported for the release of [14C]20∶4 label but at a slower rate and at a much lower percentage indicating that [14C]20∶4 had been incorporated into part of a more reactive pool. The specificity of the fatty acid release induced by tannin and β‐1,3‐glucan, a known agonist for 20∶4 release, was also examined. Both agonists promoted an increase in the levels of free 20∶4 and of other fatty acids. A comparison of the absolute increases of each of the fatty acids indicated that tannin caused a preferential increase in the mass of free 20∶4, whereas β‐1,3‐glucan evoked a selective increase in the mass of 16∶0.
Essential fatty acids alter the activity of manganese‐superoxide dismutase in rat heart
Authors: Phylactos Andreas C. , Harbige Laurence S. , Crawford Michael A.
Published: November 2006

The effects of oil‐derived dietary essential fatty acids on the activities of mitchondrial Mn‐SOD (manganese‐superoxide dismutase) and cytosolic cupric zinc‐superoxide dismutase (Cu/Zn‐SOD) were investigated in rat heart. A control group of rats was fed a stock diet for 29 d, and a second group was fed on a fat‐free diet. Three other groups were fed fat‐free diets that were supplemented with (i) borage oil, which is rich in linoleic (18∶2n−6) and γ‐linolenic (18∶3n−6) acids, (ii) fungal oil, which is rich in γ‐linolenic, but low in linoleic acid, or (iii) evening primrose oil, which is rich in linoleic acid and low in γ‐linolenic acid. An increase in the percentage composition of arachidonic acid (20∶4n−6) in both the choline and ethanolamine phospholipids, together with a decrease in linoleic acid in ethanolamine phospholipids, were found in heart membranes after feeding the rats with diets containing borage oil or fungal oil as compared to those fed the stock diet. The respective activities of Mn‐SOD in rats fed the borage or fungal oil diets were also significantly higher than in rats fed the stock diet alone. No change in cytosolic Cn/Zn‐SOD activity was observed. Dietary supply of linoleic acid‐rich evening primrose oil resulted in an increased proportion of choline phospholipid linoleic acid without any changes in arachidonic acid content or in the activity of Mn‐SOD. By contrast, a reduction in the activity of Mn‐SOD was detected in rats fed a fat‐free diet. These results show that the activity of heart mitochondrial Mn‐SOD is influenced by dietary essential fatty acids, whereas the activity of cytosolic Cu/Zn‐SOD remained unaffected.
Interactions between medium‐chain and long‐chain triacylglycerols in lipid and energy metabolism in growing chicks
Authors: Mabayo Remedios T. , Furuse Mitsuhiro , Murai Atsushi , Okumura Jun‐ichi
Published: November 2006

The combined effects of dietary medium‐chain triacylglycerols (MCT) and long‐chain triacylglycerols (LCT) on lipid and energy utilization in chicks were investigated. Corn oil was used as the LCT source, and trioctanoin (8∶0) was used as the MCT source. The efficiency of dietary energy utilization (such as metabolizable energy values and fat and energy retention) decreased linearly as the level of MCT increased, but the efficiency of dietary protein utilization (protein retained per protein consumed) was not affected in a consistent manner. Fecal saturated and monounsaturated fatty acid composition was dependent on the dietary fatty acid composition, whereas fecal linoleic acid content was not. It is concluded that dietary MCT and LCT influence each other to some degree, with respect to protein and lipid metabolism in chicks. Moreover, in most cases, the nutritional characteristics of each triacylglycerol, including food efficiency and fat and energy retention, are independent of each other in growing chicks.
The acute effects of a single very high dose of n−3 fatty acids on plasma lipids and lipoproteins in healthy subjects
Authors: Svaneborg N. , Møller J. M. , Schmidt E. B. , Varming K. , Lervang H. H. , Dyerberg J.
Published: November 2006

Forty healthy volunteers were allocated in a double blind, randomized study to receive either 20 g of n−3 polyunsaturated fatty acids (PUFA) or 20 g of n−6 PUFA at their evening meal. The effect on plasma lipids and lipoproteins of this single dose of fish oilvs. corn oil was studied the next morning, 14 h after ingestion. Plasma triglycerides and very low density lipoprotein‐cholesterol significantly decreased (33%) after n−3 PUFA (P<0.001), and significantly (P<0.01) more than after intake of n−6 PUFA. The decrease in plasma triglycerides after n−3 PUFA ingestion was more pronounced in subjects with higher baseline levels of triglycerides (P<0.001). Total cholesterol decreased after both supplements, but did not differ between the supplements. Low density lipoprotein‐cholesterol did not change, and high density lipoprotein‐cholesterol significantly decreased in subjects given n−3 PUFA compared to baseline, but not when compared to subjects receiving n−6 PUFA. In conclusion, we have shown that a single very high dose of n−3 PUFA has a pronounced hypotriglyceridemic effect, which is directly related to the initial plasma level.
Tissue phospholipid fatty acid composition in genetically lean (Fa/−) or obese (fa/fa) zucker female rats on the same diet
Authors: Guesnet Ph. , Bourre J. ‐M. , Guerre‐Millo M. , Pascal G. , Durand G.
Published: November 2006

The fatty acid composition of serum total lipids, of phospholipids of various organs (liver, heart, kidney), and of nervous structures (brain, retina, sciatic nerve, myelin, synaptosomes) have been compared in lean (Fa/−) and genetically obese (fa/fa) Zucker female rats. Both received a standard commercial diet including 37% of 18∶2n−6 and 5% of n−3 polyunsaturated fatty acids (PUFA), 1.7% of which were in the form of 20∶5n−3 and 22∶6n−3. In comparison with lean rats, the results for the obese rats pointed out (i) no difference in the fatty acid composition of nervous structures: (ii) a decrease of 18∶2n−6 (from −8% to −35%) and of 20∶4n−6 (from −9% to −49%) in serum, liver and in kidney; this was compensated for by an increase in 20∶3n−6 (from +30% to +320%) and in total n−3 PUFA (from +68% to +76%); (iii) a decrease of 20∶4n−6 (−18%) and of 22∶6n−3 (−24%) in heart compensated for by an increase in 18∶2n−6 (+39%) and in 20∶3n−6 (+233%); and (iv) constant levels of total PUFA (n−6 and n−3) in the various fractions studied, except in serum where this level decreased (−23%). Finally, except for the nervous structures, tissue phospholipids of obese rats included a lower proportion of 20∶4n−6 and a higher proportion of 20∶3n−6. This resulted in a significant reduction in the 20∶4n−6/20∶3n−6 ratio; by contrast, the 20∶3n−6/18∶2n−6 ratio increased. The results suggest that in Zucker rats, the obese character (fa/fa) affects the desaturation‐elongation process of 18∶2n−6 to 20∶4n−6 by specifically decreasing Δ5‐desaturase activity.
Exchange of free cholesterol between plasma and erythrocytes from hyperthyroid and hypothyroid ratsin Vitro
Authors: Ruggiero F. M. , Cafagna F. , Quagliariello E.
Published: November 2006

In our previous studies, we found that circulating thyroid hormone levels alter cholesterol partition between plasma and erythrocytes by changing the phospholipid content of erythrocytes (Ruggiero, F.M.,et al. (1984)Horm. Metabol. Res. 16, 37–40; Ruggiero, F.M.,et al. (1987)Lipids 22, 148–151). As an extension of this work, we now followed the exchange of free cholesterol between plasma and erythrocytes in control, hyperthyroid and hypothyroid rats under various experimental conditionsin vitro. In control rats, erythrocytes incubated with plasma at 37°C for 4 hr lose 10% of cholesterol which was esterified by lecithin: cholesterol acyltransferase (LCAT) present in the plasma. In hyperthyroid rats, erythrocytes incubated with plasma lose 30% of cholesterol within the same time. By contrast, in the case of hypothyroid rats incubation for 4 hr was necessary to transfer 24% of free cholesterol from plasma to erythrocytes. Inhibition of cholesterol esterification did not affect the loss of erythrocyte cholesterol in control and in hyperthyroid rats. Ca2+ increased the LCAT activity in the plasma of these rats. The findings shed light on the role of thyroid hormones in regulating cholesterol levels in plama through active cholesterol transfer between plasma and erythrocytes.