bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative autoxidative and photolytic stabilities of tocols and tocotrienols
Authors: Lehmann J. , Slover H. T.
Published: November 2006

The relative stabilities of selected individual tocols and tocotrienols and of equimolar mixtures of either α‐ plus γ‐ or α‐ plus δ‐ tocopherols were determined in methyl myristate and methyl linoleate during autoxidation and photolysis. Solutions containing 0.05% of the appropriate tocopherol(s) or tocotrienols were subjected to UV light (254 nm) or to a flow of 4.3 ml/min of oxygen, both at 70 C. Tocopherols (T) and tocotrienols (T−3) were determined by gas chromatography without preliminary separation or purification. Under photolytic conditions, stabilities in increasing order in methyl myristate were γ‐T−3<α‐T−3<δ‐T<α‐T <γ‐T<5,7‐T<β‐T and in methyl linoleate were α‐T<α‐T−3≤γ‐T−3≤β‐T≤5,7‐T <γ‐T<δ‐T. A solvent effect on the initial rate of photolysis was observed for 5‐methyl substituted tocols but not for the tocols with an unsubstituted 5‐position or for the tocotrienols. Under autoxidative conditions, stabilities in increasing order in methyl myristate were α‐T=α‐T−3 <β‐T−3<γ‐T−3<δ‐T−3<γ‐T<δ‐T=β‐T and in methyl linoleate were α‐T<α‐T−3 <γ‐T−3<β‐T<γ‐T<δ‐T. Tocopherols were much more stable during autoxidation in methyl myristate than they were in methyl linoleate. In mixtures, there was no significant protection of α‐tocopherol by either γ‐ or δ‐tocopherol under any of the conditions used. However, α‐tocopherol was highly effective in protecting γ‐ and δ‐tocopherols in methyl myristate during both photolysis and autoxidation and in methyl linoleate during photolysis. During autoxidation in methyl linoleate, α‐tocopherol protection of γ‐ and δ‐ tocopherols after 24 hr was slight tough measurable.
Localization of a source of marine odd chain‐length fatty acids. II. Seasonal propagation of odd chain‐length monoethylenic fatty acids in a marine food chain
Authors: Paradis M. , Ackman R. G.
Published: November 2006

The unusual occurrence of elevated levels of odd chain length fatty acids (OCFA) in smelt taken during winter months in Jeddore Harbour, Nova Scotia, is due to the dietary intake of large numbers of the amphipodPontoporeia femorata (Kröyer). Sampling over two winters confirms that the seasonal peak period for this amphipod, in stomachs is mid‐December to the end of February. The distributions of monoethylenic isomers are compared to distinguish exogenous and endogenous smelt dietary features in terms of the geographically limited phenomenon of high OCFA levels and the essential absence of biological activity for these acids.
An enzymatic protective mechanism against lipid peroxidation damage to lungs of ozone‐exposed rats
Authors: Chow C. K. , Tappel A. L.
Published: November 2006

The effects of whole animal exposure to ozone and of dietary α‐tocopherol on the occurrence in rat lung of lipid peroxidation and alteration of the activity of enzymes important in detoxification of lipid peroxides were studied. Exposure to 0.7 and 0.8 ppm ozone continuously for 5 and 7 days, respectively, significantly elevated the concentration of TBA reactants, primarily malonaldehyde, produced by lipid peroxidation, as well as the activities of glutathione (GSH) peroxidase, GSH reductase and glucose‐6‐phosphate (G‐6‐P) dehydrogenase. As a logarithmic function of dietary α‐tocopherol (0, 10.5, 45, 150 and 1500 mg/kg), the increase in formation of malonaldehyde and the increase in activities of GSH peroxidase and G‐6‐P dehydrogenase were partially inhibited. The activity of GSH reductase was not affected by dietary α‐tocopherol. The concentration of malonaldehyde and the activity of GSH peroxidase in lung were linearly correlated (p<0.001). This study confirmed the occurrence of lipid peroxidation in the lung during ozone exposure and revealed an enzymatic mechanism against damage. An apparent compensation mechanism is that with increased lipid peroxides there is increased activity of GSH peroxidase, which in turn increases lipid peroxide catabolism. The increased activities of GSH reductase and G‐6‐P dehydrogenase also function in the protective chain by providing increased levels of GSH and NADPH, respectively.
Enzymatic synthesis of glucosylsphingosine by rat brain microsomes
Authors: Curtino Juan A. , Caputto Ranwel
Published: November 2006

Labeled glucosylceramide was formed when rat brain microsomes were incubated with14C‐UDP‐glucose. When sphingosine was added to the incubation mixture, labeled glucosylsphingosine was synthesized, and the formation of glucosylceramide increased.
Phospholipid synthesis in mammary tissue. Choline and ethanolamine kinases: Kinetic evidence for two discrete active sites
Authors: Infante J. P. , Kinsella J. E.
Published: November 2006

Choline and ethanolamine kinases are located in the high speed supernatant of lactating bovine mammary gland. Maximum activities of choline and ethanolamine kinases were observed at pH 9.2 and 8.0, respectively, with the rate of ethanolamine phosphorylation being 1/15 that of choline phosphorylation. Activation energies of 29 joules (Q10‐1.5) and 31 joules (Q10=1.5) were calculated between 3.4 and 31.3C for choline kinase and ethanolamine kinase, respectively. Above 31.3 C, the Arrhenius plot deviated from linearity for both enzymes, suggesting that denaturation was occurring. An apparent Km of 0.25 mM for choline was obtained for choline kinase activity. The apparent Km of ethanolamine kinase for ethanolamine was unusually high (17 mM), and activity was not linear with increasing protein concentration. Activity was tripled and the Km decreased to 2.5 mM when the enzyme preparation was washed with butanol: benzene mixture, suggesting the presence of an endogenous competitive inhibitor(s), with respect to ethanolamine. Choline kinase was not affected by the solvent wash. Substrate competition studies revealed that choline kinase was slightly inhibited competitively by ethanolamine (apparent Ki=19–21 mM), whereas choline was a potent competitive inhibitor of ethanolamine kinase (apparent Ki=0.33–0.50 mM). The results indicated that these two kinase activities were mediated by two distinct active sites, possibly on a single protein. The significance of choline in the regulation of phosphatidylethanolamine synthesis is discussed.
Structure‐function activity of azasterols and nitrogen‐containing steroids
Authors: Kabara Jon J. , Holzschu Donald L. , Catsoulacos Demokri Tos P.
Published: November 2006

Thirty‐nine nitrogen‐containing steroids were tested against two gramnegative, five gram‐positive, and two yeast organisms. Many of these steroids have been preiously reported to inhibit various metabolism processes involving sterol metabolism. While low minimal inhibitory concentration (MIC) values were recorded for sterol producing yeast, growth of bacteria which contain no sterols was also inhibited. Structure‐function studies provided no relationship between biological activitity and hypocholesteremic effects of these azasteroids. A hypothesis put forward is that amino and azasteroids are effectors of membrane which, in the case of mitochondria, lead to changes in adenosine triphosphate levels and/or dehydrogenase activity. Their effects on sterol metabolism, there‐fore, may be of secondary consideration.
Saturated and monounsaturated long chain hydrocarbon profiles of lipids from orange, grapefruit, mandarin and lemon juice sacs
Authors: Nagy Steven , Nordby Harold E.
Published: November 2006

Saturated and monounsaturated long chain hydrocarbons were determined in four citrus fruit species‐orange, grapefruit, mandarin and lemon. All species manifested their own intrinsic profiles. In the saturated fraction, iso and anteiso hydrocarbons comprised between 45 and 58% of the total hydrocarbons, while in the monounsaturated fraction the range was 2 to 22%. As a general rule, odd‐numbered, iso hydrocarbons were always found at percentages higher than their anteiso homologs.
The incorporation of 2‐aminoethylphosphonic acid into rat liver diacylglyceroaminoethylphosphonate
Authors: Curley Jean M. , Henderson Thomas O.
Published: November 2006

Rats intravenously administered (14C) 2‐aminoethylphosphonic acid (AEP) incorporated ca. 16% of the total injected compound into liver lipids. Thin layer chromatography and selective chemical and enzymatic hydrolysis of the labeled lipids demonstrated that essentially all of the radioactivity was in one compound, diacylglycerol‐AEP, the phosphonate analog of phosphatidylethanolamine. Lipids from kidneys, heart, skeletal muscle, adipose, pancreas and brain were examined and found to contain less than 2% collectively of the total injected radioactivity. The residues from the tissues contained ca. 3.2% of the total injected (14C) AEP.
Fluorescent products of lipid peroxidation: II. Methods for analysis and characterization
Authors: Malshet V. G. , Tappel A. L. , Burns V. M.
Published: November 2006

The effects of pH and of the metal chelator, europium (Tric[2,2,6,6‐tetra‐methyl‐3,5‐heptanedionate]), upon fluorescence of lipid peroxidation products were tested, and fluorescence decay times and fluorescence polarization values were determined. Measurements of fluorescence intensity showed that the fluorescence of these compounds was quenched at basic pH and that it was restored by adjustment of pH to neutrality. Metal chelator decreased the fluorescence intensity 8–15%. pH Effects and metal coordination effects are useful for analysis and characterization of these fluorescent products. Fluorescence polarization and fluorescence decay times are also useful analytical techniques for characterization of fluorescent products.
Preparation of psychosines (1‐O‐hexosyl sphingosine) from cerebrosides
Authors: Radin Norman S.
Published: November 2006

A convenient method for large or small scale preparation of psychosine from cerebroside has been developed by adaptation of published procedures. Cerebroside is refluxed with butanol and aqueous KOH, then the KOH is removed with perchloric acid. The fatty acids are removed by extraction with hexane and the excess perchloric acid is removed by partitioning between chloroform, ethanol, and water.
Specificity ofGeotrichum candidum lipase with respect to double bond position in triglycerides containingcis‐octadecenoic acids
Authors: Jensen Robert G. , Gordon Dennis T. , Heimermann Wayne H. , Holman Ralph T.
Published: November 2006

Fifteen approximately random, mixed, triacylglycerols, each of which contained 12∶0, 14∶0, 9, 12–18∶2, 16∶0 and only one positional isomer ofcis 18∶1 (Δ2 through Δ16), were synthesized. These mixtures were used as substrates for the lipase from the microorganismGeotrichum candidum to define the specificity of the enzyme for unsaturated fatty acids. Comparatively small quantities of the 18∶1 isomers, other than 9–18∶1, were hydrolyzed. Relatively large amounts of 18∶2 were released from all substrates. There was no preference between 9–18∶1 and 18∶2. The positional isomers other than 9–18∶1 accumulated in the di‐ and mono‐acylglycerols.
Leaf wax of oats
Authors: Tulloch A. P. , Hoffman L. L.
Published: November 2006

Leaf wax of oats (Kelsey variety) consists of hydrocarbons (5%), esters (10%), free alcohols (45%), free acids (2.5%), β‐diketone (5.5%), hydroxy‐β‐diketones (2.5%), and unidentified (29%). Wax on leaf blades contains more free alcohols than wax on leaf sheaths, and wax on the flag leaf sheath contains more β‐diketone than wax on the rest of the plant. Principal hydrocarbons are C29, C31, and C33. The esters, mainly C44–C48 and C52, are probably C18–C22 and C26 esters of hexacosanol. Free alcohols are almost entirely hexacosanol. The β‐diketone is hentriacontane‐14, 16‐dione. Hydroxy β‐diketones are a mixture of 5‐, 6‐ and 7‐hydroxyhentriacontane‐14, 16‐diones in the proportions 58∶35∶7. The wax also contains a small amount (0.5%) of 1,16‐hexacosanediol.
Effect of oxidation on chemical spectral and immunochemical properties of egg yolk lipoprotein
Authors: Hara I. , Shimasaki H. , Sato J.
Published: November 2006

Studies are reported on the changes in the chemical, spectral, and immunochemical properties of the low density lipoprotein fraction of hen's egg yolk during oxidation. Sonication for 15 min at 15–20 C in the presence or absence of iron gave an increase in thiobarbituric value and UV absorption but did not influence the fluorescence. Storage at 50 C in the absence of iron after sonication for 15 min at 15–20 C produced increases in absorptivity in the fluorescence and UV spectra, as well as thiobarbituric values. Similar changes were produced without sonication in the presence of iron in ca. 8 days storage at 50 C. Ethylenediaminetetraacetic acid completely inhibited the effect of copper, as well as iron, under these conditions. Immunoelectrophoresis pattern was effected by oxidation under conditions that gave an increase in absorptivity in the fluorescence spectra. The first change appeared to involve a minor fast moving component which decreased even when oxidation was inhibited by ethylenediaminetetraacetic acid. As the oxidation proceeded, the mobility of the major component in the immunoelectrophoresis analysis was altered. The major reaction affecting the immunochemical properties appeared to be between the product of lipid oxidation and the protein moiety.
Preferential labeling of brain cholesterol by {3‐14C}D(−)‐3‐hydroxybutyrate
Authors: Devivo D. C. , Fishman M. A. , Agrawal H. C.
Published: November 2006

{3‐14C}D(−)‐3‐hydroxybutyrate or {2‐14C}glucose was injected subcutaneously into 15‐day old suckling rats. The animals were killed 3, 6 and 24 hr later by decapitation. Brain proteins, cholesterol, glycolipids, and phospholipids were extracted and prepared for counting. The {3‐14C}D(−)‐3‐hydroxybutyrate injected animals showed ca. twofold greater labeling (p<.001) of brain cholesterol compared to {2‐14C}glucose; whereas the {2‐14C}glucose injected animals showed ca. fourfold greater labeling (p<.001) of brain proteins than {3‐14C}D(−)‐3‐hydroxybutyrate at all time points. The difference in labeling of brain glycolipids and phospholipids was less striking, but greater labeling was apparent at each time point in the {2‐14C}glucose injected animals compared to the {3‐14C}D(−)‐3‐hydroxybutyrate injected animals. These data suggest that D(−)‐3‐hydroxybutyrate behaves differently than glucose, being a more direct precursor for brain cholesterol biosynthesis and a less effective precursor for brain protein synthesis. Further studies ascertaining the specific activities of the precursors are necessary to quantitatite the respective contributions of D(−)‐3‐hydroxybutyrate and glucose to lipid and protein synthesis in the rat brain during development.
Fatty acid composition of carotenoid esters in soybean and rapeseed oils
Authors: Froehling P. E. , Van Den Bosch G. , Boekenoogen H. A.
Published: November 2006

The amounts of the different carotenoids (lutein, lutein monoesters and diesters) in soybean and rapeseed oil were determined through a combination of column chromatography and UV spectrometry. The lutein diesters in the oils have been isolated by a combination of column and thin layer chromatography. Identification and determination of the amount of the various fatty acids of the lutein diesters have been carried out by means of gas chromatography after transesterification of the fatty acids to their methyl esters. Comparison of the fatty acids of the lutein diesters with those of the triglycerides of the oils revealed a striking difference. First, the fatty acids of the lutein diesters have shorter chains than the triglycerides acids. Secondly, the lutein fatty acids are more saturated than the fatty acids of the triglycerides of the corresponding oils. However the amount of linoleic acid in the case of the fatty acids of the lutein diesters in rapeseed oil is greater than that in the fatty acids of the triglycerides in rapeseed oil.
Immunochemical quantification of human plasma Lp(a) lipoprotein
Authors: Albers John J. , Hazzard William R.
Published: November 2006

The Lp(a) lipoprotein was purified from human plasma by ultracentrifugation and gel filtration on 6% agarose. It contained 27% protein, 65% lipid, and 8% carbohydrate. Quantification of the Lp(a) lipoprotein was performed by radial immunodiffusion. Both within‐assay and between‐assay coefficients of variation were inversely concentration dependent, decreasing from 20% and 27%, respectively, at 3 mg/100 ml to 7% and 12%, respectively, at concentrations above 8 mg/100 ml. The lower limit of sensitivity of the assay was 1.5 mg/100 ml. Of 340 unrelated fasting subjects tested, 81% had levels of the Lp(a) lipoprotein exceeding this lower limit. The distribution of Lp(a) concentrations in this population was skewed with a mean of 14 mg/100 ml and a median of 8 mg/100 ml. Lp(a) lipoprotein was not significantly correlated with age, sex, or cholesterol or glyceride concentrations.
Nutritional effects of partially hydrogenated low erucic rapeseed oils
Authors: Beare‐Rogers J. L. , Nera E. A.
Published: November 2006

The incidence of cardiac lesions in male rats fed rapeseed oil (Brassica campestris, cultivar ‘Span’) was lower with partially hydrogenated oil (iodine value 78) than with the liquid oil which had been treated in various ways. Another rapeseed oil (Brassica napus, cultivar ‘Tower’) was similarly improved when hydrogenated to iodine value 76.6, but not at iodine value 97.1, as demonstrated in both Sprague‐Dawley and Wistar rats. The improved nutritional quality of hydrogenated oil appeared not to be related to the decreased concentration of linolenic acid, because that fatty acid in linseed oil with or without erucic acid did not increase the incidence of lesions. A relatively high concentration of docosahexaenoic acid in the cardiac fatty acids was observed in adversely affected groups, but a lower concentration was found with the appropriately hydrogenated rapeseed oil.
Analytical13C NMR: Detection, quantitation, and positional analysis of butyrate in butter oil
Authors: Pfeffer P. E. , Sampugna Joseph , Schwartz Daniel P. , Shoolery James N.
Published: November 2006

The amount of butyrate contained in a complex mixture of butter oil triglycerides was 10.3 mole % as determined by natural abundance13C Fourier transform pulse nuclear magnetic resonance (NMR) spectroscopy. This NMR technique also demonstrated the primary isomeric positioning (>97%) of the butyrl group without the need for altering or fractionating the fat mixture.
Ether‐linked glycerolipids in human brain tumors
Authors: Albert Daniel H. , Anderson Carl E.
Published: November 2006

In this investigation, the lipid composition of a number of human brain tumors was determined and compared to that of normal adult brain. Glioblastomas (11 samples), astrocytomas (4 samples), an acoustic neurinoma, an oligodendroglioma, and a meningioma were analyzed. All of the tumors had substantial levels (0.8–3.4% of total phospholipids) of choline plasmalogen which was present in only trace amounts in normal brain. With the exception of the acoustic neurinoma and the meningioma, the concentration of alkylacylglycerophosphorylcholine was also higher in the tumors than in normal brain. Neutral lipids of brain tumors also contained high concentrations of both alkyl (1.6–4.8% of total neutral glycerolipids) and alkenyl diacyl glycerol (3.8–10.1%). The results from this investigation indicate that increases in etherlinked glycerolipids may be characteristic of human brain tumors.
The effect of lipids on taurocholate absorption from intestinal loops in the rat
Authors: Sklan D. , Budowski P.
Published: November 2006

The rates of uptake and serosal trans‐fer of [14C]‐labelled taurocholate (7.77 mM in bicarbonate buffer, pH 6.5) were determined in situ in ligated segments of rat intestine in the presence of lipids. Oleic acid, monoolein, lecithin, and lysolecithin enhanced taurocholate uptake and transfer in the jejunum, each lipid exhibiting and optimal concentration at which the bile acid fluxes were maximal. The maximal rates of bile acid uptake observed with the various lipids were close to four times the uptake rates found with the lipid‐free taurocholate medium, whereas serosal transfer rates under optimal conditions were enhanced about six‐fold. The optimal concentrations differed widely among the various lipids, being inversely related to the lipids' polarity. Simultaneous measurement of taurocholate and [3H]‐labelled oleic acid showed that under optimal conditions, when the molar concentration of oleic acid was about equal to that of the bile acid, the fatty aicd and bile acid also exhibited closely similar rates of absorption. At other fatty acid concentrations, the fractional rate of absorption of the bile acid was much lower than that of the fatty acid. The rates of uptake and serosal transfer of pure taurocholate by the ileum exceeded those of the jejunum by factors of about 7 and 15, respectively, but in the presence of lipids this difference in absorptive capacity for bile acid between the distal and proximal segment largely disappeared.
Involvement of cytochrome b5 in the oxidative desaturation of linoleic acid to γ‐linolenic acid in rat liver microsomes
Authors: Okayasu Takako , Ono Teruo , Shinojima Kazunori , Imai Yoh
Published: November 2006

The effects of antibodies against microsomal electron‐transport components on the in vitro activity of Δ6‐desaturation of linoleic acid to γ‐linolenic acid have been studied in intact microsomal membranes of rat liver. Reduced nicotinamide adenine dinucleotide (NADH) or reduced nicotinamide adenine dinucleotide phosphate (NADPH) (0.87 mM) served as electron donors, and effectively prompted the Δ6‐desaturase activities with yields of about 1.1 to 1.3 nmol per mg of protein in 10 min. Of the two antibodies studied under the same in vitro conditions, i.e., rabbit antisera preparations against rat liver microsomal hydrophilic parts of cytochrome b5 and NADPH‐cytochrome c reductase, only the antibody against cytochrome b5 demonstrated a marked ability to inhibit the Δ6‐desaturase activity. This evidence supports a participation of cytochrome b5 in the Δ6‐desaturation of linoleic acid and suggests a pathway analogous to the Δ9‐desaturation of stearyl‐CoA.
Changes in rat heart phospholipid composition after rapeseed oil feeding
Authors: Dewailly P. , Sezille G. , Nouvelot A. , Fruchart J. C. , Jaillard J.
Published: November 2006

The influence of long duration rapeseed oil feeding with high or low levels of erucic acid has been investigated on rat heart phospholipids. The rats treated for 20 wk with rapeseed oil containing 46.2% erucic acid showed a twofold increase in the sphingomyelin content of the heart. Treatment with primor rapeseed oil (3.7% erucic acid) for 20 wk did not modify phospholipid composition of rat heart. The fatty acid patterns of phosphatidylethanolamine and phosphatidylcholine were slightly influenced by the high erucic rapeseed oil; eicosenoic acid was incorporated preferentially into position one, but erucic acid showed a random distribution in both. After high erucic rapeseed oil feeding, 22∶1 was incorporated into cardiolipin (5.6%) and sphingomyelin (10.5%). The incorporation of 22∶1 into sphingomyelin was associated with an increase of the percentage of 24∶1 (14.6%) and a decrease of saturated long chain fatty acid (22∶0, 24∶0) percentages. Primor rapeseed oil caused a slight increase of 24∶1 and a decrease of 22∶0 and 24∶0 in rat heart sphingomyelin. As cardiolipin is localized in the inner membrane of mitochondria and sphingomyelin in plasma and microsomal membranes, the acyl‐moiety alterations of both phospholipids might be correlated to the pathological lesions of rat heart after a long duration of rapeseed oil feeding.
Sterol composition ofNeurospora crassa
Authors: Renaud R. L. , Subden R. E. , Pierce A. M. , Oehlschlager A. C.
Published: November 2006

The sterols extracted from freeze‐dried, log‐phase cultures ofNeurospora crassa were separated by thin layer and analyzed by capillary gas liquid chromatography and mass spectrometry. Ergosterol, episterol, and ergosta‐7,22 dienol were the major sterols of the free sterol fraction. The major esterified sterols, which constituted 4.95% of the total sterol fraction, were ergosterol, episterol, and ergosta‐ 7,22,24(28)‐trienol, with lesser quantities of 4α‐methyl‐ergosta‐8,24(28)‐dienol. With the exception of lanosterol, all sterols were alkylated at the C‐24 position.
Fatty acid metabolism of the calanoid copepodParacalanus parvus: 2. Palmitate, stearate, oleate and acetate
Authors: Moreno Victor J. , de Moreno Julia E. A. , Brenner Rodolfo R.
Published: November 2006

The de novo biosynthesis of fatty acids in the wild, calanoid copepodParacalanus parvus was studied. The incubation of labeled acetate proved the de novo biosynthesis of saturated and monounsaturated even fatty acids from 14 to 20 carbons and the 22∶1 acid. Saturated and monounsaturated uneven fatty acids from 15 to 21 carbons were also synthesized. The copepod could not synthesize linoleic and α‐linolenic acids. By administration of [1‐14C]palmitate, [1‐14C] stearate and [1‐14C]oleate, it was possible to elucidate the general pattern of the de novo biosynthesis of fatty acids in the wildP. parvus.
The use of essential fatty acid deficient rats to study pathophysiological roles of prostaglandins. Comparison of prostaglandin production with some parameters of deficiency
Authors: Parnham M. J. , Vincent J. E. , Zijlstra F. J. , Bonta I. L.
Published: November 2006

In a retrospective study on essential fatty acid deficient, (EFAD) rats used to study pathophysiological roles of prostaglandins (PGs) slight increases in the linoleic acid content of the diet were found to gradually restore the depressed growth rate and to increase the reduced endogenous PG production. These apparently poorly deficient animals had a serum triene tetraene (ω9:ω6) ratio much higher than the value of 0.4 used as a criterion for EFA deficiency by nutritionists. Changes in body weight, serum ω9∶ω6 and platelet PG production were not correlated with each other. Feeding rats on a diet containing <0.1 mg/g/linoleic acid led to decreasing platelet PG production as the degree of EFA deficiency increased. At this high level of deficiency, a serum ω9∶ω6 ratio of 6 or over was achieved. This high ratio may be taken as anindicator of the degree of EFA deficiency required for studies of PG deprivation, but PG production by the tissue investigated or by plalets should preferentially be measured.
Metabolism of linoleic acid in the cat
Authors: Sinclair A. J. , McLean J. G. , Monger E. A.
Published: November 2006

Cats fed a diet containing linoleate as the only polyunsaturated fatty acid showed extremely low levels of arachidonate in the plasma lipids, as well as an increase in linoleate, eicosadienoate and an unknown fatty acid. Administration of [1‐14C] linoleic acid and [2‐14C] eicosa‐8,11,14‐trienoic acid to cats showed that in the liver there was no conversion of the [1‐14C] 18∶2 to arachidonate, whereas there was significant metabolism of [2‐14C] 20∶3 to arachidonate. It was found when methyl‐γ‐linolenate was fed to cats that the level of 20∶3ω6 and 20∶4ω6 in the erythrocytes increased significantly. These results show that there is no significant Δ6 desaturase activity in the cat, whereas chain elongation and Δ5 desaturase enzymes are operative. The unknown fatty acid was isolated from the liver lipids and shown to be a 20‐carbon fatty acid with 3 double bonds and which by gas liquid chromatography could be separated from 20∶3ω9 and 20∶3ω6. The presence of the Δ5‐desaturase activity and the results of the ozonolysis studies indicated that this unknown fatty acid was eicosa‐5,11,14‐trienoic acid.
The formation of phosphatidylinositol by acylation of 2‐acyl‐sn‐glycero‐3‐phosphorylinositol in rat liver microsomes
Authors: Holub Bruce J. , Piekarski Jerry
Published: November 2006

The conversion of 2‐acyl‐sn‐glycero‐3‐phosphorylinositol into phosphatidylinositol via acyl‐CoA: 2‐acyl‐sn‐glycero‐3‐phosphorylinositol acyltransferase activity was found to occur in rat liver microsomes. Over a wide range of conditions, stearic acid was preferred over palmitate by the acyltransferase when these acids were presented in mixtures as acyl‐CoA derivatives. The potential importance of this enzyme activity for the entry of stearic acid into the 1‐position of hepatic phosphatidylinositol is further supported by its greater preference for stearate relative to the acyl‐CoA: 2‐acyl‐sn‐glycero‐3‐phosphorylcholine acyltransferase under certain assay conditions.
Hydroxy acids and estolide triglycerides ofHeliophila amplexicaulis L.f. Seed oil
Authors: Plattner Ronald D. , Payne‐Wahl Kathleen , Tjarks Larry W. , Kleiman Robert
Published: November 2006

Thirty percent of the fatty acids fromHeliophila amplexicaulis seed oil are hydroxy acids, primarily lesquerolic acid (14‐hydroxy‐cis‐11‐eicosenoic acid) with a trace of a new fatty acid, 16‐hydroxy‐cis‐13‐docosenoic acid. The hydroxy acids in the oil are found exclusively in the 1 and/or 3 positions of the triglycerides and are completely acylated with C20 or C22 saturated or monoenoic acids.
Hypolipidemic effects in monkeys of ML‐236B, a competitive inhibitor of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase
Authors: Kuroda Masao , Tsujita Yoshio , Tanzawa Kazuhiko , Endo Akira
Published: November 2006

The fungal metabolite ML‐236B, a competitive inhibitor of 3‐hydroxy‐3‐methylglutaryl CoA reductase, has been shown to be significantly effective in lowering serum cholesterol levels in cynomolgus monkeys at doses of 20–50 mg/kg per day. Levels of serum phospholipids and triglycerides were, however, not significantly changed by the administration of the drug. Of the serum lipoprotein fractions, a β‐lipoprotein corresponding to low density lipoprotein was preferentially reduced by the drug treatment. Fecal excretion of neutral sterols was unaffected but that of bile acids was slightly elevated by the administration of ML‐236B.
The adsorption of bile salts on activated carbon
Authors: Krasopoulos J. C. , De Bari V. A. , Needle M. A.
Published: November 2006

Activated carbon (AC) has been shown to be effective in reducing serum cholesterol and triglycerides. The mechanism for this action is proposed to be a result of the removal of bile salts in the gut. In this paper, the adsorption of cholate, glycocholate, taurocholate, chenodeoxycholate and deoxycholate on AC is studied in vitro. The results indicate that AC has a high capacity for bile salts, completely removing them from solutions of up to 5 mM and at a rate consistent with physiological activity. Of the 2 types of AC tested, one was shown to exhibit greater capacity and selectivity over the other. A negligible effect was seen with variation of pH through the range 7–9. Desorption occurs in the presence of bile salt‐free buffer, but to a minimal extent. Based on these data, the adsorption of bile salts by AC appears to be a likely mechanism for AC‐induced reduction of serum lipids.
Sterol composition of ungerminated and germinated spores of the Vesicular‐Arbuscular Mycorrhizal fungus,Glomus caledonius
Authors: Beilby J. P. , Kidby D. K.
Published: November 2006

The sterol composition of spores of the Vesicular‐Arbuscular Mycorrhiza,Glomus caledonius, have been examined by combined gas liquid chromatography‐mass spectrometry (GLC‐MS). The sterols identified were cholesterol, 24‐methylcholesterol, 24‐methylenecholesterol and 24‐ethylcholesterol. The sterols 24‐methylcholesterol, 24‐methylenecholesterol and 24‐ethylcholesterol have not previously been reported as components of fungi in the Zygomycotina. The spores were germinated on agar and the major changes in sterol esters, free and bound sterols were studied over a period of 21 days. The total sterol content continually increased during the growth period; 24‐methylcholesterol and cholesterol were shown to be the major sterols.
Occurrence of plant sterols in aquatic vertebrates
Authors: Takagi Toru , Sakai Akira , Hayashi Kenji , Itabashi Yutaka
Published: November 2006

Plant sterols were found by gas liquid chromatography in the sterols of five species of aquatic vertebrates; mackerel (Scomber japonicus), rainbow trout (Salmo gairdnerii), smelt (Osmerus dentex), sardine (Sardinops melanosticta) and chimera (Chimera phantasma). The sterols of chimera liver, sardine flesh and sardine viscera contained 9.0, 2.4 and 3.1% of C28 and C29 sterols in addition to 86.7, 96.6 and 95.2% of cholesterol. The occurrence of norcholestandienol, campesterol, β‐sitosterol and C28 stanol was shown by combined gas chromatography‐mass spectrometry. Sperm whale (Physeter catodon) sterols consisted of more than 99% cholesterol with only traces of 22‐dehydrocholesterol.
Analysis of autoxidized fats by gas chromatography‐mass spectrometry. IV. Soybean oil methyl esters
Authors: Frankel E. N. , Neff W. E.
Published: November 2006

An unusual isomeric distribution of hydroperoxides has been found in soybean oil esters oxidized at low levels (peroxide values below 50). The unexpectedly high concentration of the 12‐hydroperoxide isomer is in marked contrast to the isomeric composition of oxidized pure linolenate. The different isomeric hydroperoxides observed at low levels of oxidation may contribute through their decomposition to the unique flavor deterioration of soybean oil. Quantitative gas chromatographymass spectrometry (GC‐MS) used in this study provides for the first time an answer to the basic question of which hydroperoxides contribute to the state of oxidation of soybean oil. Results of GC‐MS were confirmed by capillary gas chromatography. Analyses of highly oxidized soybean esters (peroxide values 468 and 2352) reveal the same main compounds as those found in oxidized pure linoleate, together with small amounts of oleate and linolenate hydroperoxides.
The effect of essential fatty acid‐deficient diet on the levels of prostaglandins and their fatty acid precursors in the rabbit brain
Authors: Hassam A. G. , Willis A. L. , Denton J. P. , Stevens P. , Crawford M. A.
Published: November 2006

Rabbits were maintained on an EFA‐deficient diet. After eight weeks on this diet, lipid analysis showed no major alterations in the levels of brain dihomo‐gamma‐linolenic and arachidonic acids when compared with animals maintained on the standard laboratory diet. However, there were substantial reductions in the brain prostaglandin contents. It is suggested that the dihomo‐gamma‐linolenic acid and arachidonic acid utilized for prostaglandin production may be more directly related to the dietary essential fatty acid input rather than to the size of the precursor pool in the principal phospholipids.
Improved synthesis of choline phospholipids
Authors: Brockerhoff Hans , Ayengar Narayan K. N.
Published: November 2006

Choline phospholipids (diether and dialkyl analogs of phosphatidyl choline, cholesteryl phosphocholine) were prepared, in yields of 72–83%, by condensation of the diglyceride analogs (or cholesterol) with phosphorusoxychloride and choline toluene‐sulfonate.
Effects of estrogens and progestins on high density lipoproteins
Authors: Krauss R. M. , Lindgren F. T. , Wingerd J. , Bradley D. D. , Ramcharan S.
Published: November 2006

High density lipoprotein (HDL) levels are known to be higher in women than in men, and to increase with estrogen use. To assess the effects of estrogens on HDL subspecies, analytic ultracentrifuge measurements of HDL were compared in 11 menopausal estrogen users and 16 controls. The difference in mean schlieren patterns between the groups showed a significantly higher level of HDL with flotation rate (F1.20o)>1.5 (predominantly HDL2) in the users. This was similar to the difference in HDL seen between nonusers of hormones and age‐matched males. A previous study had shown that users of combination oral contraceptives had increased levels of HDL with F1.20o≤3.5 (primarily HDL3) suggesting that the estrogen effect on HDL is altered by the presence of added progestin. The progrestin effect was studied here in more detail in two women with type V hyperlipoproteinemia treated with norethindrone acetate. Reduction in serum triglyceride was accompanied by a reduction in HDL, predominantly in the less dense species (HDL2). Among groups of oral contraceptive and noncontraceptive estrogen and progestin users whose HDL‐cholesterol levels have been reported recently, there was a direct correlation (r=0.86, p<.001) between mean HDL‐cholesterol and triglyceride levels. Endogenous hormonal influences on HDL were assessed by serum hormone and lipoprotein measurements at weekly intervals during two consecutive menstrual cycles in four healthy females. An increase in HDL of highest flotation rate (F1.20o 5–9) was seen, which corresponded with the time of ovulation raising the possibility of pituitary as well as gonadal hormone effects on HDL.
Diet‐induced changes in the fatty acid composition of mouse hepatocyte plasma membranes
Authors: Hopkins G. J. , West C. E.
Published: November 2006

Hepatocyte plasma membranes were isolated from the livers of mice fed either a low fat diet or high fat diets containing polyunsaturated or saturated fat. The combined rate and isopycnic ultracentrifugation technique which was used produced highly purified hepatocyte plasma membrane fractions. The efficacy of the procedure was checked by electron microscopy and the assay of marker enzymes for the different subcellular organelles. Mice were maintained on a low fat diet until 60–70 days of age, when they were fed high fat diets containing polyunsaturated or saturated fat. The hepatocyte plasma membrane lipids of mice fed the polyunsaturated fat diet for 4 wk contained increased proportions of the major dietary unsaturated fatty acid, linoleic acid, and increased proportions of arachidonic acid. The proportion of linoleic and arachidonic acids decreased with continued feeding of the polyunsaturated fat diet. The hepatocyte plasma membrane lipids of mice fed the saturated fat diet contained increased proportions of oleic acid.
Antioxidants in neoplastic cells: I. Changes in the antioxidative capacity of mouse neuroblastoma cells measured by a single‐phase assay
Authors: Arneson Richard M. , Aloyo Vincent J. , Germain Glen S. , Chenevey James E.
Published: November 2006

Cultured mouse neuroblastoma cells exhibit a striking increase in antioxidative capacity during the transition from logarithmically dividing cells to nondividing, neurite‐bearing cells. Two physically separable phenomena are involved: (a) the membrane pellet of neurite‐bearing cells is highly resistant to lipid peroxidation, and (b) the postmicrosomal supernatant of these cells inhibits peroxidation in rat liver mitochondria and other biological membranes. A precise, single‐phase assay has been developed for assessing antioxidant levels in lipid extracts. By means of this assay, the increase in membrane resistance to lipid peroxidation has been correlated with a threefold increase in the antioxidant activity of the neuroblastoma neutral lipid fraction. This finding implies that generation of a neutral lipid antioxidant (or antioxidants) is involved in the profound increase in antioxidative capacity which occurs in differentiating neuroblastoma cells.
High‐pressure liquid chromatography of autoxidized lipids: I. Methyl oleate and linoleate
Authors: Neff W. E. , Frankel E. N. , Scholfield C. R. , Weisleder D.
Published: November 2006

Autoxidized methyl oleate and linoleate were reduced with NaBH4 and fractionated with a preparative high‐pressure liquid chromatography (HPLC) reverse phase column. Products characterized from reduced‐oxidized oleate included monohydroxy‐ and dihydroxyotadecenoates, dihydroxy‐ and epoxyoctadecanoates. Products characterized from reduced‐oxidized linoleate included hydroxy‐cis,trans‐ andtrans,trans‐octadecadienoates, monohydroxy‐, dihydroxy‐, trihydroxy‐, epoxyhydroxy‐, and epoxyoctadecenoates. Quantitation of oxidation products by HPLC was in agreement with gas chromatography of trimethylsilyl ether derivative. Epoxyoctadecanoate in oleate and epoxy‐ and epoxyhydroxyoctadecenoates in linoleate were the most abundant secondary oxidation products. Some mechanisms are discussed to explain formation of these secondary products.
Effects of ethanol intake on lipoprotein lipase activity in adipose tissue of fasting subjects
Authors: Nilsson‐Ehle Peter , Carlstrom Sven , Belfrage Per
Published: November 2006

Ethanol (ca. 1 g/kg body weight) was given alone or together with glucose or lipid (mixed triglycerides) perorally to young, fasting subjects. The changes with time (0–6 hr) of lipoprotein lipase activity (LLA) in adipose tissue, plasma glycerol, triglyceride, insulin, blood glucose, and alcohol concentrations were followed. A maximal mean blood alcohol concentration of 0.09% (w/v) was obtained 1 hr after ingestion with no apparent intoxicating effects. Ethanol intake prevented the previously observed [Nilsson‐Ehle, P., S. Carlström and P. Belfrage,Scand. J. Clin. Lab. Invest.35∶373 (1975)] glucose‐induced rapid elevation of adipose tissue LLA but had small effects on this enzymatic activity when given alone or together with lipid. Confirming results by others, ethanol intake decreased plasma glycerol concentration and increased plasma triglycerides, especially after intake of lipid. It is suggested that ethanol intake interferes with the normal carbohydrate‐induced elevation of adipose tissue LLA after a mixed meal, thereby decreasing the removal capacity for circulating dietary lipid and causing enhanced and prolonged alimentary hyperlipemia.
The effect of dietary erucic acid on cardiac triglycerides and free fatty acid levels in rats
Authors: Kramer John K. G. , Hulan Howard W.
Published: November 2006

Male Sprague‐Dawley rats, 3 weeks of age, were fed semisynthetic diets containing test oils at 20% by weight for 3 days, 1 week, and 16 weeks. The test oils contained up to 22.3% erucic acid. Growth retardation was evident in rats fed rapeseed oil high in erucic acid, and soybean oil and Tower rapeseed oil diets containing about 5% erucic acid. Cardiac triglyceride accumulation was found in rats fed diets containing about 5% erucic acid but not in rats fed Tower rapeseed oil which contains 0.2% of this acid. The cardiac free fatty acid levels were low, 50–100 μg/g of wet heart tissue, and were not affected by feeding diets containing about 5% erucic acid. Feeding a diet containing a high erucic acid rapeseed oil did result in higher free fatty acid levels but only at 3 days and 1 week; the level at 16 weeks was similar to the other oils. The fatty acid analysis of cardiac triglycerides and free fatty acids showed high percentages of erucic acid at 3 days and 1 week; at 16 weeks these levels had declined significantly. The results indicate that the accumulated erucic and eicosenoic acids, at 3 days and 1 week, accounted for the increase in cardiac free fatty acids when rats were fed the high erucic acid rapeseed oil. There appears to be no evidence that the early cardiac triglyceride or free fatty acid accumulation is related to the formation of the long term myocardial lesions.
The role of dietary protein in hypercholesterolemia and atherosclerosis
Authors: Carroll K. K.
Published: November 2006

Rabbits become hypercholesterolemic and develop atherosclerotic lesions when fed a cholesterol‐free, semipurified diet. This provides a useful experimental model in which a moderate hypercholesterolemia can be maintained for long periods of time. The elevation of plasma cholesterol and development of atherosclerosis are dependent on the kind of protein in the diet and can be prevented by replacing casein with isolated soy protein. Feeding trials with enzymatic digests or mixtures of amino acids indicate that this difference is at least partly due to the differing amino acid composition of the two proteins. Rabbits on the soy protein diet showed higher rates of oxidation and turnover of cholesterol than those on the casein diet. Dietary protein has generally been considered to be of little significance in the etiology of atherosclerosis in humans, but evidence is accumulating which indicates that it can have a significant influence on human plasma cholesterol levels.
Effect of phthalate esters on serum cholesterol and lipid biosynthesis in liver, testes, and epididymal fat in the rat and rabbit
Authors: Bell Frank P. , Patt Carol S. , Gillies Peter J.
Published: November 2006

Lipid biosynthesis was studied in vitro in liver, testes, and epididymal fat obtained from rats and rabbits fed di‐(2‐ethylhexyl)phthalate for 4 weeks at levels of 0.5% and 1.0%, respectively. Several differences in response of the two species to DEHP feeding were observed. In rats, but not in rabbits, DEHP feeding significantly reduced the incorporation of labeled mevalonic acid into total sterols (p <0.02), digitonin‐precipitable sterols (p<0.01), and squalene (p<0.05). Inhibition of hepatic sterologenesis previously observed with DEHP feeding in the rat was also observed in the rabbit. In liver minces from the DEHP‐fed rabbits, incorporation of3H‐mevalonic acid into C27 sterols (cholesterol) and C30 sterols (lanosterol) was significantly reduced by about 40% (p<0.05 and p<0.01, respectively), whereas the incorporation of14C‐glycerol 3‐phosphate into phospholipids, and the combined fraction of monoglyceride + diglyceride, was significantly increased (p<0.001 and p<0.01, respectively). In studies with epididymal fat, DEHP feeding did not affect the total incorporation of14C‐acetate or3H‐mevalonate into total saponifiable and nonsaponifiable lipids of either the rat or rabbit. However, in the rat, significantly less of the14C‐acetate (p<0.02) and3H‐mevalonate (p<0.01) that was incorporated appeared in the combined fraction of cholesteryl ester + squalene. In addition, DEHP feeding significantly reduced serum cholesterol (p<0.01) in the rat but not in the rabbit. The results of this study indicate that DEHP feeding is associated with alterations in tissue lipid metabolism and that there are species differences in the response of tissues to DEHP.
Steryl glycoside biosynthesis
Authors: Grunwald Claus
Published: November 2006

The existence of steroid glycosides has been known for many years and, more recently, their derivatives have been described. Steroid glycosides have been isolated from a number of organisms, however, the largest number of these compounds are found in plants. As to glycoside biosynthesis, the sterols are the most extensively studied steroid group. Of the sterols, only the 4‐demethyl sterols have been isolated as glycosides. The glycosidic bond formation is mediated through nucleotide sugars, and UDP‐glucose appears to be the most active glycosyl donor. In cell‐free studies, the pH of the incubation medium is quite critical and depends on the tissue under investigation, but generally the optimum is near pH 7.0. Formation of steryl glycosides is particulate in nature and is stimulated by ATP, Ca2+, and Mg2+. Similar results are obtained, regardless whether the sterol or the sugar moiety is labeled. Formation of acylsteryl glycosides could occur via two pathways: through the acylation of steryl glycosides or through the transfer of an acylglycosyl unit to a sterol moiety. Results from in vitro experiments suggest that acylsteryl glycoside formation occurs via steryl glycosides. Two acyl transfer reactions have been demonstrated; one is microsomal in nature and involves phosphatidylethanolamine, while the other reaction involves a soluble enzyme and requires galactolipids. In vivo experiments, however, indicate that a second pathway may also exist. If cholesterol‐4‐14C is used as substrate, a highly radioactive component can be isolated which is readily converted to acylsteryl glycoside, but not to free sterol or steryl glycoside. It is suggested that this component is an intermediate in acylsteryl glycoside biocynthesis. At present, the nature of the component is unknown. It is quite stable, and acid hydrolysis produces free sterol. Saponification produces two products which in thin layer chromatograms closely resemble acylsteryl glycoside.