bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic lipid changes in rapidly proliferating hepatic smooth endoplasmic reticulum during acute dexamethasone treatment of adrenalectomized rats
Authors: Holloway Caroline Tobia , Margolis Ronald N. 
Published: November 2006

AbstractThe regulation by the cell of subcellular membrane components is dependent on a highly complex balance of nutritional, hormonal and metabolic events. We have characterized the lipid components of the endoplasmic reticulum (ER) of the liver of adrenalectomized (ADX) rats and the response of these membrane components to glucocorticoid administration. Membrane microviscosity as measured by fluorescence depolarization of 1,6‐diphenylhexatriene (DPH) was measured and correlated with lipid composition and content of the membranes. In the ADX rat, a significant increase in membrane microviscosity of the smooth endoplasmic reticulum (SER) was observed and this was accompanied by an increase in the cholesterol content/mg protein and a decrease in the phospholipid content/mg protein. A change in the fatty acyl chain composition is observed with a significant increase in the mole percentage of arachidonic acid (20∶4) and an accompanying decrease in saturated fatty acids. Within 2–6 hr of dexamethasone administration, a decrease in membrane microviscosity is observed that returns this value to one similar to that for normal control animals. Both the cholesterol and the phospholipid contents/mg protein are likewise restored to levels similar to that for control animals beginning at the 2‐hr time point. The arachidonic acid and saturated fatty acid content of the constituent phospholipids do not begin to return to values similar to those for control animals until 6 hr after dexamethasone administration. From these experiments, we can conclude that glucocorticoids play a significant regulatory role in determining the lipid properties of rat hepatic microsomal membranes.
Detection of hydroxy fatty acids in biological samples using capillary gas chromatography in combination with positive and negative chemical ionization mass spectrometry
Authors: Stan H. ‐J. , Scheutwinkel‐Reich M. 
Published: November 2006

AbstractThe most common method for use in the structural analysis of hydroxy fatty acids in biological samples is the gas chromatography‐mass spectrometry (GC‐MS) analysis of trimethylsilyl ethers of the methyl esters using electron impact ionization. A comparison of electron impact (EI) with chemical ionization mass spectrometry (CI‐MS) shows that CI‐MS is the superior technique. All ions necessary for structural analysis are observed at sufficiently high levels of intensity when methane or isobutane are used as reactant gases. The molecular weight can be determined from the ion group M+H, M‐15 and M+H−90. The ionic series M+H−n×90 enables one to determine the number of hydroxyl groups. The position of the hydroxyl groups can be derived from the fragments of the α‐cleavage of the fatty acid chain. The application of heptafluorobutyrates as derivatives for hydroxy fatty acid methyl esters shows advantages in the trace analysis of these compounds. Heptafluorobutyrates exhibit useful mass fragmentation patterns in the positive as well as in the negative CI mode. With methane as the reactant gas, M+H usually is base peak in positive mass spectra. The ionic series M+H−n×214 leads to the number of hydroxy groups in the molecule. In the negative mass spectra, M and M‐20 are indicative for the molecular weight. The ion group m/z 213, 194 and 178 at high levels of intensity is typical for heptafluorobutyrates. The advantage of the application of heptafluorobutyrates is the high sensitivity which can be obtained in trace analysis using negative MS. Heptafluorobutyrates of hydroxy fatty acids gave a 20‐fold higher response in the negative scan mode compared to that of the positive. The detection limit for heptafluorobutyrates in negative CI‐MS was on the order of 1 fg (10−15 g).
Occurrence of squalene in skin surface lipids of the otter, the beaver and the kinkajou
Authors: Lindholm Jane S. , Downing Donald T. 
Published: November 2006

AbstractIn a previous survey of the skin surface lipids of 46 mammalian species, it was found that only 3, the otter, the beaver and the kinkajou, contained components with chromatographic mobility similar to squalene, and in each case, this material was the predominant constituent. The materials in question have now been isolated from each of these species and identified as squalene by thin layer chromatography, gas chromatography and infrared spectroscopy. The occurrence of squalene in the surface lipids of these particular species cannot be explained on the basis of either their evolutionary relationship or ecological niche.
The interaction of human plasma low density lipoproteins with glycosamino‐glycans: Influence of the chemical composition
Authors: Kostner Gerhard M. , Zechner Rudolf , Bihari‐Varga Magdolna , Gruber E. 
Published: November 2006

AbstractHuman plasma of 5 normolipemic individuals was incubated for 24 hr at 37 C in the presence or in the absence of lecithin: cholesterol acyltransferase (LCAT)‐inhibitors. Plasma steored at 4 C served as a control. The low density lipoprotein (LDL) fractions of the samples were isolated and investigated with respected to changes in chemical composition and complexing activity with glycosamino glycans (GAG).Incubation of plasma in the presence of LCAT inhibitors caused a significant increase of LDL triglycerides at the expense of cholesteryl esters. Incubation with active LCAT not only changed the core but also the surface constituents (decrease in phospholipids and in free cholesterol).The amount of GAG bound per mg of LDL was not uniformly changed in samples incubated after LCAT inhibition. LDL isolated from plasma incubated in the presence of LCAT, on the other hand, showed a significant reduction in GAG binding.The ratio of free cholesterol: GAG in the complex was most significantly reduced in LCAT‐modified LDL. There was in addition a highly significant correlation between the LDL:GAG ratio in the complex and the free cholesterol and phospholipid content of the LDL samples.It is concluded that alterations in surface lipid constitutents of LDL strongly after their interaction with sulfated polysaccharides, an effect which may be relevant also in vivo for the interaction of LDL with cell surfaces and intercellular matrices.
A diurnal variation of hepatic acid cholesteryl ester hydrolase activity in the rat
Authors: Tanaka Mitsuo , Yonekura Ryooji , Iio Toshihiro , Tabata Toshikazu 
Published: November 2006

AbstractThe diurnal variation in lysosomal acid cholesteryl ester hydrolase (Acid CEH), (EC 3.1.1.13) has been examined in fed, fasted and adrenalectomized rats. The Acid CEH activity of normal rat liver exhibits a diurnal rhythm with maxima at 06.00 hours and minima at 18.00 hours, but such a rhythm was not observed in spleen and brain. This rhythm was abolished after fasting for two days, and the resulting Acid CEH activity remained constant at the minimum level. However, adrenalectomy did not abolish the diurnal rhythm. These results indicate that the Acid CEH activity varies according to a diurnal rhythm with maxima and minima separated by approximately 12 hr. Further, it is evident that the appearance of this rhythm is dependent upon dietary, but not adrenal hormone influence.
Cardiac lipid changes in rats fed oils enriched in saturates and their apparent relationship to focal heart lesions
Authors: Kramer J. K. G. , Farnworth E. R. , Thompson B. K. 
Published: November 2006

AbstractWeanling male Spraque‐Dawley rats were fed diets containing 20% by weight corn, soybean or low erucic acid rapeseed oils or mixtures of the latter two with cocoa butter or triolein for 1, 2, 3 or 4 weeks. These diets previously had been fed to the same strain of rats for 16 weeks, and a reduction in the incidence of focal heart lesions had been observed with the addition of cocoa butter, but not triolein. The cardiac lipid classes and the fatty acid and alkenyl ethers of the cardiac phospholipids were analyzed to determine if changes could be attributed to the observed cardiopathological response, and at what time. Cardiac lipid classes changed during post‐weaning development, but only triacylglycerol was diet‐related. A number of fatty acid changes were observed in the cardiac phospholipids which reflected the relative concentration of saturates, monounsaturates, linoleic acid and linolenic acid in the diet, but only the changes in saturates and the C22 polyunsaturated fatty acids from the linolenic acid family appeared to be related to the incidence of focal heart lesions. Arachidonic acid and the total C22 polyunsaturated fatty acids remained fairly constant throughout the feeding trial. Cardiac diphosphatidylglycerol was least affected by dietary manipulation, while nervonic acid increased in cardiac sphingomyelin when small amounts of erucic acid were present in the diet. Fatty acid changes were essentially completed after one week on the experimental diets, whereas changes in the alkenyl ethers took two to three weeks.
Mass spectra of pyrrolidides of oxy, hydroxy and trimethylsilyloxy octadecanoic acids
Authors: Tulloch A. P. 
Published: November 2006

AbstractPyrrolidides of 16 isomeric oxooctadecanoic acids and 17 isomeric hydroxyoctadecanoic acids and their trimethylsily (TMS) ethers have been prepared and their mass spectra measured. Comparison of spectra of all the isomers has shown the variation in amide‐ and substituent‐directed fragmentation with position of the substitutent on the 18 carbon chain. Five diagnostic ions are present in spectra of most oxo pyrrolidides, and the most important one is formed by cleavage between the carbons α and β to the oxo group on the amide side. Mass spectra of hydroxy pyrrolidides have four diagnostic ions; the principal one in most spectra is formed by α‐cleavage at the oxygenated carbon on the terminal methyl side. There are four characteristic ions in spectra of the trimethylsiloxy pyrrolidides, and the two formed by α‐cleavage on one or the other side of the oxygenated carbon are the most important. Spectra of the 2‐, 3‐ and 4‐substituted isomers are considerably different from those of the other isomers. Mass spectra of pyrrolidides of three specifically deuterated oxo acids and of eight deuterated hydroxy acids and their trimethylsilyl ethers also were recorded and used to confirm the mode of formation of almost all the ions in the spectra. Two unusual hydrogen migrations, from the carbon α to the oxygenated carbon on the terminal methyl side, are involved in fragmentation of the trimethylsilyl ethers. Spectra have been compared with those of the corresponding oxygenated methyl esters.
Chylomicron remnant and asialoglycoprotein metabolism are independent
Authors: Cooper Allen D. , Coleman David 
Published: November 2006

AbstractBecause of the considerable similarities between the hepatic metabolism of chylomicron remnants and asialoglycoproteins, the hypothesis that they might share a cell surface receptor or a common step in internalization was tested. Unlabeled chylomicron remnants did not reduce the binding of125I‐asiaglycoprotein to plasma membranes, but did compete for125I‐chylomicron remanant binding. The converse also was true. This suggested the receptors were distinct. The two substances did not compete with each other for removal by the isolated perfused rat liver. This suggests that no potentially common post binding events can become rate limiting.In conclusion, despite similarities in their removal and metabolism, chylomicron remnants and asialoglycoproteins are metabolized independently.
Free, esterified and glucosidic sterols in cocoa butter
Authors: Staphylakis K. , Gegiou D. 
Published: November 2006

AbstractSterol lipids of cocoa butter (cocoa beansLome Tongo) were fractionated into free sterols, steryl esters (SE), steryl glucosides and acylated steryl glucosides (ASG). 4‐Desmethyl, 4‐methyl and 4,4′‐dimethyl sterols or triterpene alcohols, which were isolated as free sterols or which resulted from hydrolysis, were determined by thin layer chromatography‐flame ionization detection and identified by gas chromatography and combined gas chromatography‐mass spectroscopy. Free sterols comprise the main sterol fraction in cocoa butter. Esterified sterols amount to 11.5% of total sterols and glucosidic sterols to 16.3%. Fatty acids and D‐glucose from hydrolysis of esters and glucosides were analyzed. The fatty acids of SE and ASG are richer in unsaturated fatty acids than cocoa butter total fatty acids.
Hydrolysis of intralipid by pancreatic lipase and phospholipase A2‐gel filtration studies
Authors: Grataroli Renée , Charbonnier Monique , Nalbone Gilles , Lairon Denis , Chabert Christiane , Hauton Jacques C. , Lafont Huguette 
Published: November 2006

AbstractIntralipid was incubated with pancreatic lipase (EC 3.1.1.3) and/or phospholipase A2 (EC 3.1.1.4) at two bile salts/phosphatidylcholine molar ratios and at two different triglyceride hydrolysis rates using various amounts of lipase.Incubations were studied by gel filtration. Results show: (i) During lipase action, three phases of lipids coexist: an emulsified phase, a micellar phase and an intermediate heavy phase sized between the two others. The equilibrium between each phase is dependent upon the bile salts concentration. (ii) Under these conditions, pancreatic lipase was at 60% bound to the emulsified phase, whereas pancreatic phospholipase A2 was bound at 94% to the micellar phase.
The relative incorporation of arachidonic and eicosapentaenoic acids into human platelet phospholipids
Authors: Weaver B. J. , Holub B. J. 
Published: November 2006

AbstractThe incorporation of arachidonic acid (AA) as compared to eicosapentaenoic acid (EPA) into human platelet phospholipids was tested by incubating washed platelets with a known mixture of [3H]AA and [14C]EPA. Following incubation, the platelet lipids were extracted, the individual phospholipids—phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE)—were separated by thin layer chromatography, and their corresponding [3H]/[14C] ratios were determined. Based on a [3H]/[14C] ratio of unity for the substrate mixture, the PC, PS, PI and PE exhibited ratios of 0.55, 0.93, 1.12 and 0.74, respectively, which were significantly different from 1.00 in all instances except in the case of PS. These results indicate that PC and PE selectively incorporated EPA, while PI showed preference toward AA. These selectivities may account partly for the differing AA/EPA mass ratios that have been observed among the individual phospholipids of human subjects consuming fish oils.
Analysis of positional distribution of fatty acids in palm oil by13C NMR spectroscopy
Authors: Ng Soon 
Published: November 2006

AbstractThe13C NMR spectrum of the carbonyl carbons of the acyl groups of triacylglycerols of palm oil has been shown to give the composition of saturated, oleic and linoleic acyl groups at the 1,3‐positions and at the 2‐position of the glycerol moiety. Except for the lack of differentiation of the saturated fatty acids, the13C NMR technique provides the same information as the tedious enzymatic hydrolysis cum fatty acid analysis. The carbonyl carbon of the linolenic acyl group (18∶3,[cis, cis, cis]‐9, 12, 15) has a chemical shift which is only 0.005 ppm to low frequency of that of the linoleic acyl group (18∶2,[cis, cis]‐9, 12), so that the two resonances may not be distinguishable (or resolved) even at a high magnetic field.
Quantitative relationships between dietary linoleate and prostaglandin (Eicosanoid) biosynthesis
Authors: Mathias Melvin M. , Dupont Jacqueline 
Published: November 2006

AbstractEssential fatty acid deficiency consistently depresses eicosanoid (prostaglandin E2, F2, and I2and thromboxane) biosynthesis independent of sampling protocols. Tissue fatty acid analyses support the hypothesis that the decrease is due in part to depression of arachidonate and accumulation of eicosatrienoate (n−9). Research on the alteration of eicosanoid biosynthesis by dietary linoleate supplementation is reviewed extensively. Responses of whole blood, lung, liver and heart eicosanoid synthesis to feeding eight concentrations of dietary linoleate between 0 and 27 energy percent are reported. It is concluded that stimulation, depression and no change in eicosanoid production could be equally well documented as a response to linoleate supplementation. Evidence for the obvious mechanism that alterations in precursor fatty acid composition are a possible explanation is fragmentary and inconsistent. The appropriate sampling techniques appear not to be established at this time and most likely are species, gender and tissue specific.
Cholesterol and triglyceride distributions in an adult employee population: The Pacific Northwest Bell Telephone Company health survey
Authors: Hoover J. Joanne , Walden Carolyn E. , Bergelin Robert O. , Wahl Patricia W. , Albers John J. , Hazzard William R. , Knopp Robert H. 
Published: November 2006

AbstractPlasma cholesterol and triglyceride are presented for 4503 adult employees of the Pacific Northwest Bell Telephone Company. Cross‐sectional age and sex specific means and percentiles are shown. Females are classified by use or nonuse of exogenous sex hormones. Comparisons are examined among these groups, between blacks and whites, and among education and occupation categories. In these cross‐sectional data, cholesterol and triglyceride generally increase with age and exhibit distinct differences by sex and by hormone use.
The influence of linoleic acid intake on electron transport system components
Authors: Abuirmeileh N. M. , Elson C. E. 
Published: November 2006

AbstractGroups of young rats were fed a basal diet with beef tallow (BT) or corn oil (CO) added to provide 4 or 19% energy as linoleic acid. Mitochondria isolated from the livers of the rats fed the CO contained a significantly lower concentration of b‐type cytochrome and significantly higher concentrations of cytochromes c, c1 and aa3. Cytochrome c oxidase activity also was elevated. The spectral characteristics of the b‐type cytochrome varied between the 2 groups. The mitochondria from the rats fed CO contained relatively more of the cytochrome b‐558 component whereas mitochondria from the BT group contained more of the cytochrome b‐562 component. The classical antimycin A inhibition of electron transport between cytochromes b and c1 was partially bypassed in mitochondria with the more fluid membrane. The activation energy for cytochrome c oxidase in mitochondria from this group was significantly higher. These differences may be traced to the physical characteristics of the inner mitochondrial membrane.
Phthalic ester, an artifactual contaminant in diazomethane prepared from N‐methyl‐N‐nitroso‐p‐toluenesulfonamide for the derivatization of prostaglandins
Authors: Mai J. , Kinsella J. E. , Chou J. S. 
Published: November 2006

AbstractDuring analyses of prostaglandin (PG) methoxime methyl trimethylsilyl (MO‐ME‐TMS) ether derivatives by gas chromatography, we consistently observed a contaminant peak which we identified as di‐2‐ethylhexyl phthalate (DEHP). The diazomethane prepared from N‐methyl‐N‐nitroso‐p‐toluenesulfonamide (MNTSA) using the Diazald kit was the major source of DEHP. Several other materials also were significant sources. The concentrations of DEHP in these materials were quantified by gas chromatography‐mass spectrometry.
Fatty acid profile of myocardial lipid in populations consuming different dietary fats
Authors: Shenolikar Indushekhar 
Published: November 2006

AbstractHuman hearts from medico‐legal autopsies were obtained from 3 regions of India where the edible oils used are different. These 3 population groups consumed either mustard oil (Calcutta), coconut oil (Trivandrum) or peanut oil (Madras). Among the saturated fatty acids, lauric acid was found only in the myocardium of subjects from Trivandrum (3.5% of the total fatty acids [TFA]), heptadecanoic acid only in the samples from Madras (1.4% TFA) and arachidic acid only in those of Calcutta (1.9% TFA). Erucic acid was present only in the samples received from Calcutta and acted as a marker of mustard oil consumption. It had a mean concentration of 5.6% TFA. From the level of erucic acid present in the myocardial lipid, it is apparent that, at the level of intake of mustard oil prevalent in India, the risk of developing myocardial fibrosis is slight.
Comparison of fatty acids and lipids of smolting hatchery‐fed and wild atlantic salmonSalmo salar
Authors: Ackman R. G. , Takeuchi Toshio 
Published: November 2006

AbstractIn Atlantic Canada the Atlantic salmonSalmo salar change from the parr stage to the smolt stage while still in fresh water, preparatory to migration to salt water. In some stocks this takes place during the second overwintering. In several hatcheries where the water temperature drops to 0–0.5 C and the ponds ice over, there is a high incidence of erosion of the dorsal and pectoral fins and sometimes of the caudal fin. No disease organism has been identified, and the lesions heal over in most cases. Dietary fatty acids were thought, to be a factor. A detailed study of lipid recoveries and classes has shown that in the skins of abnormal fish the total lipid, is 7.8% compared to 4.7% in control fish.Unexpectedly, an analysis of one lot of healthy smoltstage wild fish showed that whole bodies have only a quarter of the lipid of comparble hatchery fish. Comparison of fatty acids showed that wild fish lipids include a higher proportion of arachidonic acid than those of the hatchery fish. in the latter, linoleic acid is provided readily by diet but the elongation to arachidonic acid evidently does not proceed. These results suggest that the smolt lipid, is involved intimately with either the cause of the dermal lesion or is a defense mechanism, possibly mediated through oxygenase activity.
Distribution of14C after oral administration of (U‐14C)labeled methyl linoleate hydroperoxides and their secondary oxidation products in rats
Authors: Oarada Motoko , Miyazawa Teruo , Kaneda Takashi 
Published: November 2006

AbstractTo study the toxicity of low molecular weight (LMW) compounds formed during the autoxidation of oils,14C‐labeled primary monomeric compounds (methyl linoleate hydroperoxides) and secondary oxidation products, i.e., polymer and LMW compounds prepared from autoxidized methyl [U‐14C]linoleate hydroperoxides (MLHPO) were orally administered to rats, and their radioactive distributions in tissues and organs were compared. The polymeric fraction consisted mainly of dimers of MLHPO. For the LMW fraction, 4‐hydroxy‐2‐nonenal, 8‐hydroxy methyl octanoate and 10‐formyl methyl‐9‐decenoate were identified as major constituents by gas chromatography‐mass spectrometry (GC‐MS) after chemical reduction and derivatization. When LMW compounds were administered to rats,14CO2 expiration and the excreted radioactivity in urine in 12 hr were significantly higher than those from polymer or MLHPO administration. Maximum14CO2 expiration appeared 2–4 hr after the dose of LMW compounds. Radioactivity of the upper part of small intestines six hr after the dose of LMW compounds was higher than the values from administered polymer or MLHPO. The remaining radioactivity in the digestive contents and feces 12 hr after administration of LMW compounds was much lower than the values observed from administered polymer or MLHPO. Among internal organs, the liver contained the highest concentration of radioactivities from polymer, MLHPO and LMW fractions, and an especially higher level of radioactivity was found in liver six hr after the administration of LMW compounds. Six hours after the dose of LMW compounds, a relatively higher level of radioactivity also was detected in kidney, brain, heart and lung. These results show that the LMW compounds from MLHPO autoxidation are more easily absorbed in rat tissues than polymer and MLHPO.