bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymatic hydrolysis of 1‐monoacyl‐SN‐glycerol‐3‐phosphorylcholine (1‐lysolecithin) by phospholipases from peanut seeds
Authors: Strauss H. , Gershon Z. Leibovitz‐Ben , Heller M.
Published: December 2006

Hydrolysis of 1‐lysolecithin (1‐acyl glycerophosphorylcholine [1‐acyl GPC]) by preparations of phospholipase D from peanut seeds was investigated. 1‐Lysolecithin was hydrolyzed at a much slower rate than phosphatidylcholine (lecithin). Although Ca+2 ions are required for the cleavage of lecithin by the enzyme, their effect on the hydrolysis of lysolecithin depended upon the concentrations of the substrate: at 0.2 mM 1‐lysolecithin, Ca+2 ions increased the reaction rates, whereas at concentrations of the substrate lower than 0.1 mM, Ca+2 ions were inhibitory. A broad pH activity curve between 5 and 8 was obtained with higher rates in the alkaline range, both in the absence and presence of Ca+2 ions. The increased hydrolysis of lysolecithin due to Ca+2 was noticed over the entire pH range. Upon storage of the enzyme solutions at 4 C, decreased rates of hydrolysis of lecithin were observed, with t 1/2 values of ca. 50 and 100 days depending on the purity of the preparation. During the same period, no reduction occurred in the activity of these preparations on lysolecithin as substrate. The effects of Ca+2 ions and the analysis of the products of 1‐acyl GPC cleavage by the enzyme preparations revealed by the enzyme preparations revealed the presence of more than one enzyme and the formation of the following compounds: lysophosphatidic acids (1 acyl glycerophosphoric acids), free fatty acids, glycerophosphorylcholine, and choline. The possible pathways leading to the degradation of lysolecithin and the formation of these products include reactions catalyzed by lysophospholipase A1 (lysophosphatidylcholine 1‐acyl hydrolase, E.C. 3.1.1.5) and a phosphodiesterase (L‐3‐glycerylphosphorylcholine glycerophosphohydrolase, E.C. 3.1.4.2), in addition to phospholipase D (phosphatidylcholine phosphatidohydrolase, E.C. 3.1.4.4).
Glycosphingolipids of human plasma lipoproteins
Authors: Chatterjee Subroto , Kwiterovich Peter O.
Published: December 2006

The content and structure of glycosphingolipids (GSL) in human plasma lipoproteins were studies. The quantitative distribution of the neutral GSL(Glc‐Cer, Gal‐Glc‐Cer, Gal‐Gal‐Glc‐Cer, and GalNAc‐Gal‐Gal‐Glc‐Cer) and the principal ganglioside (AcNeu‐Gal‐Glc‐Cer) within the different lipoprotein classes was similar to that of whole plasma. The total amounts (μmol glucose/100 ml plasma) of GSL in the plasma lipoproteins of three normal subjects were VLDL (very low density lipoproteins) (trace to 0.46), LDL (low density lipoproteins) (1.08–1.48), HDL2 (high density lipoproteins2) (0.62–0.85), and HDL3 (high density lipoproteins3) (trace to 0.28). In subjects with Lp(a) lipoproteins, HDL2 rather than HDL3 contained most of the GSL in HDL. When the data were corrected for differences in the plasma concentrations of the lipoproteins, the total amounts of GSL(nmol glucose/mg lipoprotein cholesterol) were VLDL(trace to 21.20), LDL(11.70–15.36), HDL2(8.50–9.10), and HDL3(3.12). No GSL were detected in lipoprotein deficient plasma. Mass spectrometry of the trimethylsilyl derivatives of the GSL in LDL showed major fragment ions characteristic of their individual structural components. The elevated plasma levels of the GSL(2–18 fold), in a homozygote for familial hypercholesterolemia, resided in LDL which contained an absolute increase (per mg lipoprotein cholesterol) of GSL. Most, if not all, of the plasma GSL are associated with plasma lipoproteins and may have an important role in their biological functions.
A radical scavenging reaction of α‐tocopherol with methyl radical
Authors: Urano Shiro , Matsuo Mitsuyoshi
Published: December 2006

To study a radical scavenging reaction of α‐tocopherol, it was reacted with methyl radical in dimethyl sulfoxide. Two main products, a geminal dimethyl cyclohexadienone and methyl ether of α‐tocopherol, were obtained and these structures were determined by13C nuclear magnetic resonance spectroscopy. The radical methylation data of α‐tocopherol suggested that a delocalized radical species would be an intermediate.
Quantitative determination of organic solvent soluble lipofuscin pigments in tissues
Authors: Csallany A. Saari , Ayaz K. Lund
Published: December 2006

Lipofuscin pigment determination in tissue extracts was quantitated by the use of its property of fluorescence. Chloroform: methanol tissue extracts were purified on Sephadex LH‐20 columns before quantitative fluorescence measurements of the lipofuscin pigments. Interfering compounds separated by chromatography were retinol and a lower mol wt fluorescent compound. Irradiation of tissue extracts with ultraviolet light was not sufficient to eliminate the interference caused by retinol and the lower mol wt compound. Purified lipofuscin pigments from blood, lung, liver, spleen, brain, heart, and kidney tissues demonstrated distinct fluorescent emission maximum at 435 nm and excitation maxima between 345 and 350 nm.
Effect of lactation on lipolysis in rat adipose tissue
Authors: Smith R. W. , Walsh Ann
Published: December 2006

The concentrations of nonesterified fatty acids and glycerol in rat parametrial adipose tissue increased at peak lactation. Adipose tissue from lactating rats showed higher rates of release of nonesterified fatty acids and glycerol when incubated in vitro than did tissue from nonlactating rats, but there was a substantial increase in the esterification of fatty acids during involution. These results support earlier evidence that fat reserves were mobilized during lactation.
Syntheses of tetra‐ and hexadeuterated octadecenoates
Authors: Dejarlais W. J. , Emken E. A.
Published: December 2006

A study of the metabolism in man ofcis andtrans monoenoic acids required the synthesis of tetra‐ and hexadeutero‐9‐octadecenoates. Preparation of methyl 9‐octadecenoate‐8,8,11,11‐d4 (90 mol % deuterium) by the Wittig reaction was accompanied by deuterium scattering with sodium methoxide as the base but not with alkyllithium. Scattering occurred in both the aldehyde and phosphorane moieties only when the aldehyde contained deuterium on the alpha carbon. Methyl 9‐octadecenoate‐8,8,13,13,14‐14‐d6 (98 mol % deuterium) was also prepared by the Wittig reaction. The deuterated octadecenoates were formed principally ascis isomers. Thetrans isomers were produced by nitrogen oxide isomerization and separation on a silver ion column.
Phospholipid composition ofCulex quinquefasciatus andCulex tritaeniorhynchus cells in logarithmic and stationary growth phases
Authors: Jenkin H. M. , McMeans E. , Anderson L. E. , Yang T. K.
Published: December 2006

Culex quinquefasciatus andCulex tritaeniorhynchus cells were grown in spinner culture and harvested in logarithmic and stationary phases of growth. The phospholipids were extracted from the cells, and the fatty acid profiles of the phospholipid classes were determined and compared. The major components were phosphatidylcholine and phosphatidylethanolamine, constituting≥80% of the phospholipid. The fatty acid profiles of lysophosphatidylcholine, phosphatidylinositol, and cardiolipin showed changes with aging of the Culex cells and between the species. In the lysophosphatidylcholine fraction, there was an increase in saturation of the fatty acids of theC. quinquefasciatus cells, and chain lengthening occurred in both species from the logarithmic to stationary phases of growth. In the phosphatidylinositiol fraction, both Culex species showed a decrease in monoenes and an increase in polyenes, while only theC. tritaeniorhynchus cells showed an increase in fatty acid chain length with aging. TheC. quinquefasciatus cells had an increase in polyenes with aging in the cardiolipin fraction. Differences in the percentage composition of the fatty acids were shown in all the phospholipid fractions between the Culex species in the logarithmic phase of growth and all except the phosphatidylinositiol and cardiolipin fractions in the stationary phase.
Oleic and vaccenic acid levels in lipid classes of tumors
Authors: Wood Randall
Published: December 2006

The isomeric octadecenoate composition of triglyceride, phosphatidylcholine, and phosphatidylethanolamine classes from a variety of rat and mouse tumors was examined. Phosphatidylethanolamine from the tumors contained a higher percentage of octadecenoate than reported for many normal tissues. The octadecenoate fractions of the three lipid classes from various tumors consisted of ca. 75% or greater oleate, with vaccenate making up the balance. These data indicate that the loss of lipid class specificity for isomeric octadecenoates reported in hepatomas (Lipids 10∶746, 1975, andLipids 9∶987, 1974) also occurs in other tumors.
Formation oftrans‐12,13‐epoxy‐9‐hydroperoxy‐trans‐10‐octadecenoic acid from 13‐L‐hydroperoxy‐cis‐9,trans‐11‐octadecadienoic acid catalyzed by either a soybean extract or cysteine‐FeC13
Authors: Gardner H. W. , Weisleder D. , Kleiman R.
Published: December 2006

A soybean extract or an ethanolic solution of cysteine and ferric chloride catalyzed the conversion of 13‐L‐hydroperoxy‐cis‐9,trans‐11‐octadecadienoic acid to numerous products among which wastrans‐12,13‐epoxy‐9‐hydroperoxy‐trans‐10‐octadecenoic acid. When this fatty acid was treated further with the cysteine‐ferric chloride solution, 9‐hydroxy‐12,13‐epoxy‐10‐octadecenoic and 9‐oxo‐12,13‐epoxy‐10‐octadecenoic acids were formed. Thus,trans‐12,13‐epoxy‐9‐hydroperoxy‐trans‐10‐octadecenoic acid probably is an intermediate in the formation of the latter two compounds. Additionally, theerythro andthreo isomers oftrans‐12,13‐epoxy‐11‐hydroperoxy‐cis‐9‐octadecenoic acid tenatatively were identified as products.
Reaction between peroxidized phospholipid and protein: I. Covalent binding of peroxidized cardiolipin to albumin
Authors: Nielsen Henning
Published: December 2006

A system is described for study of the reaction of peroxidized cardiolipin (diphosphatidylglycerol) with albumin. Covalent binding of peroxidized cardiolipin to albumin occurs in this system as evidenced partly by a decrease in lipid‐extractable P and partly by lipid P being inseparable from the albumin by gel filtration in the presence of a detergent (sodium deoxycholate) under conditions known to separate the lipid moiety and apoprotein of lipoproteins. Based on analyses of the decrease in lipid‐extractable P, the average number of cardiolipin molecules bound covalently per molecule of albumin is about 5 when peroxidized cardiolipin (4 moles O2/mol cardiolipin) at about 10 times molar excess is allowed to react with albumin. However, the data of the gel filtration experiment indicate that the bound peroxidized cardiolipin molecules may not be evenly distributed on the albumin molecules. Therefore, the number of cardiolipin molecules bound per albumin molecule may actually vary over a range and be considerably higher for part of the albumin. The findings have been discussed in relation to peroxidation in vivo.
Occurrence of dolichol in human tissues
Authors: Rupar C. A. , Carroll K. K.
Published: December 2006

The concentration of dolichol has been determined in various human tissues obtained at autopsy. The highest levels (∼3000 μg/g wet weight) were found in testes. Liver and several other endocrine tissues contained about 1000 μg/g. Lower levels were present in other tissues examined. Only a small proportion of the total dolichol in human tissues was esterified to fatty acids.
Origin of the high saturated fatty acid content of rat fecal lipids
Authors: Grigor M. R. , Dunckley G. G.
Published: December 2006

The biohydrogenation of unsaturated fatty acids and the preferential absorption of unsaturated fatty acids over long chain saturated fatty acids from the gut have been investigated to find the origin of the high saturated fatty acid content of the facal lipids of rats fed soybean oil. Label from dietary (1‐14C)‐linoleic acid was recovered in the saturated and monounsaturated fatty acids of the fecal lipid. However, when (9,10‐3H)‐stearic acid and (1‐14C)‐linoleic acid were fed together, the isotope ratio (3H/14C) of the fecal lipid was 1.9 times that of the diet. It is concluded that both processes occur.
Phosphatidylethanolamine metabolism in rats fed a low methionine, choline‐deficient diet
Authors: Lyman R. L. , Sheehan G. , Tinoco J.
Published: December 2006

The metabolism of phosphatidylethanolamine (PE) was studied in male rats fed a low methionine diet for 7 days with or without supplemental choline. Groups of animals were injected with 2‐14C‐ethanolamine and killed at intervals thereafter up to 72 hr. Liver phospholipids were isolated, and PE and phosphatidylcholine (PC) were separated by argentation chromatography into diene (18∶2), tetraene (20∶4) and hexaene (22∶6) fractions. Fatty acid composition and the distribution of radioactivity and specific activity in the total phospholipids and in the fractions were determined. Choline deficiency did not affect total liver phospholipid, but it did increase the amount of PE and decreased that of PC. The major effect of the deficiency on phospholipid fatty acids was to decrease the proportion of PE arachidonate and to increase that of docosahexaenoate. Ethanolamine incorporation into liver PE of deficient rats was only slightly less than in the controls, but loss of the radioactivity from the PE was slower. Ethanolamine radioactivity appearing in the PC of deficient rats was about half that of the controls, even though specific activities of the PE precursors were similar to the control rats. Choline deficiency increased the biological half‐lives of the total PE and its fractions. Although the proportion of PE tetraenoic fraction was reduced, the total amount of this liver PE fraction in deficient rats was not affected. However the amount of hexaenoic fraction was doubled, and it accounted for most of the increased quantity of liver PE seen in deficient animals. The results suggested that in choline deficiency PE synthesis was delayed but not appreciably suppressed, and that limited availability of methionine for methylating the PE fractions in their proper proportions affected the concentrations of the PE fractions and impaired their normal conversion to PC.
Biosynthesis of liver glycerolipids from normal and essential fatty acid‐deficient rats:3H‐glycerol and 1‐14C linoleic acid incorporation
Authors: de Tomas Maria Elena , Mercuri Osvaldo
Published: December 2006

Normal and essential fatty acid (EFA)‐deficient rats were injected via the portal vein with a labeled solution containing3H‐glycerol and 1‐14C‐linoleic acid during a 1 min period. Livers were immediately frozen, pulverized, and the lipids extracted and fractioned by thin layer chromatography. The incorporation of3H‐glycerol and 1‐14C‐linoleic acid into the different lipid fractions was measured, and the per cent distribution and specific radioactivity determined. A parallel increase was found between the specific activity and the amount of3H‐glycerol incorporated into 1,2‐diglycerides, triglycerides, lecithin and cephalin from EFA‐deficient and normal rats. Since the amount of glycerol in each fraction studied was quite similar in both groups of rats, these findings can explain the increase in the specific activity observed in the EFA‐deficient rats. Nevertheless these facts do not necessarily imply an increased turnover rate of these molecules, since we do not know the specific radioactivity of the 1,2‐diacylglycerol precursors. A remarkable increase in the specific radioactivity of the14C‐linoleic acid incorporated into lipid fractions from EFA‐deficient rats compared with control rats was observed. While the amount of 1‐14C‐linoleic acid incorporated into neutral lipids was similar in both groups of rats, a statistically significant increase in the amount of the label incorporated into phospholipids from EFA‐deficient rats was observed. These facts suggest an increased turnover rate of the radiolinoleic acid into phospholipid molecules from EFA‐deficient rats via deacylation‐reacylation pathway.
Microbiological studies investigating mutagenicity of deep frying fat fractions and some of their components
Authors: Scheutwinkel‐Reich M. , Ingerowski G. , Stan H. J.
Published: December 2006

In this study, the Salmonella/microsome mutagenicity test according to Ames et al. (Mutation Res. 31∶347, 1975) was performed in order to detect possible mutagenicity of oxidized deep frying fat fractions. Furthermore, the mono‐, di‐, tri‐ and tetrahydroxyoctadecanoic acids and the hydroperoxide of linoleic acid were investigated as model test substances. The Ames assay was carried out with and without metabolic activation including preincubation and liquid culture procedures as described by Mitchell (Mutation Res. 54∶1, 1978). The results show no mutagenic effects for the oxidized fractions of deep frying fats nor for the model test substances. At higher concentrations, however, limited test reliability resulted from direct toxic effects on bacterial growth.
Experimental nephrotic syndrome in the rat induced by puromycin aminonucleoside: Hepatic synthesis of lipoproteins and apolipoproteins
Authors: Gherardi E. , Messori M. , Rozzi R. , Calandra S.
Published: December 2006

Hepatic synthesis of lipoproteins and apolipoproteins was investigated in male Wistar rats with severe nephrotic syndrome induced by puromycin aminonucleoside by incubating liver slices with a mixture of14C‐amino acids. Labeled lipoproteins were separated by preparative ultracentrifugation from the incubation medium after the addition of carrier plasma. The incorporation of14C‐amino acids into very low density lipoproteins (VLDL) (1.006 g/ml), low density lipoproteins (LDL) (1.006–1.063 g/ml) and high density lipoproteins (HDL) (1.063–1.210 g/ml) was increased in nephrotic liver 6.1‐, 5.7‐ and 5.0‐fold, respectively. The measurement of radioactivity associated to apolipoproteins isolated by SDS‐PAGE documented an increased incorporation into apolipoprotein E (apoE) of nephrotic VLDL (33.1% vs 20% of the total radioactivity incorporated into VLDL apoproteins) and a markedly increased incorporation into apolipoprotein A‐I (apoA‐I) of nephrotic HDL (44.3% vs 16.3% of the total radioactivity incorporated into HDL apoproteins). In nephrotic liver, the total incorporation of amino acids into apolipoproteins (apoVLDL+apoLDL+apoHDL) was increased 12.6 times for apoA‐I, 6.4 times for apoB, 5.0 times for apoE, 4.2 times for apoC+apoA‐II and 2.5 times for apoA‐IV. We suggest that, in nephrotic liver: (a) the synthesis of VLDL, LDL and HDL is increased, and (b) the total synthesis of apoA‐I is selectively increased when compared to that of the other apolipoproteins.
A rapid procedure for screening and isolating oxygenated free fatty acid metabolites from plants and natural waters
Authors: Van Rogers A. , Van Aller Robert T. , Pessoney George F. , Watkins Edward J. , Leggett Harold G.
Published: December 2006

A rapid method of isolating a relatively pure fraction of oxygenated fatty acids from plants and natural waters is described. These metabolites were isolated from aqueous extracts using octadecylsilyl silica in a reverse‐phase batch extraction method. The extraction method, together with reverse‐phase analytical high pressure liquid chromatography (HPLC), was used to establish a routine screening method for the presence of these compounds in a variety of natural sources. A reverse‐phase preparative HPLC purification method is also described.
Reduced plasma lecithin cholesterol acyl transferase activity in rats fed iron‐deficient diets
Authors: Ananda Rao G. , Thomas Crane R. , Larkin Edward C.
Published: December 2006

An iron‐deficient diet containing no fat (FF−Fe) or containing either 14% hydrogenated coconut oil (HCNO−Fe) or 14% corn oil (CO−Fe) was fed to separate groups of rats for 10 weeks. In the control group, the corresponding iron‐supplemented diets were fed FF+Fe, HCNO+Fe, CO+Fe. When rats were fed iron‐deficient diets, their plasma lecithin cholesterol acyl transferase (LCAT) activity was significantly reduced as compared to controls. Their plasma also contained relatively more cholesteryl esters (CE) than free cholesterol (CH). In rats fed FF+Fe and CO+Fe diets, plasma contained similar levels of CE and CH. In those fed HCNO+Fe diet, plasma had 40% less CE than CH. Red cell CH content was significantly greater in the CO−Fe group. Iron deficiency, as indicated by low blood hemoglobin (Hb) and hematocrit (Hct) values, was also observed only in this group. The triglyceride and phospholipid contents of plasma in rats fed iron‐deficient diets were significantly lower than of those in the control groups. Thus, changes in LCAT activity and CE/CH ratio in plasma showed the effect of iron‐deficient diet consumption even before the blood Hb and Hct levels were reduced.
The effect of dietary α‐linolenic acid in the rat on fatty acid profiles of immunocompetent cell populations
Authors: Marshall Lisa A. , Johnston Patricia V.
Published: December 2006

Analysis of diet‐induced fatty acid changes in the major phospholipids of various immune cell populations has not been previously documented, particularly modifications induced by dietary α‐linolenic acid. Rats were fed purified diets containing either 10% corn oil (CO), 10% linseed oil (LO) or 10% soybean oil‐linseed mixture (SL) for 8 weeks. The α‐linolenic to linoleic acid ratios of the diets were 1∶32, 1∶1 and 3∶1, respectively. Fatty acid analysis of cell populations isolated from the spleen, thymus, thoracic cavity and peripheral blood phospholipids showed increases in ω3 fatty acids accompanied by decreases in the ω6 fatty acids when diets high in α‐linolenic to linoleic acid ratios were fed. The extent of change observed was dependent on the magnitude of the α‐linolenic to linoleic acid ratio. Both magnitude of change and the specific fatty acids altered varied with the cell population examined.
The effects of partially hydrogenated marine oils on the mitochondrial function and membrane phospholipid fatty acids in rat heart
Authors: Blomstrand Rolf , Svensson Lennart
Published: December 2006

The influence of dietary partially hydrogenated marine oils containing docosenoic acid on rat heart mitochondrial membrane phospholipid fatty acid composition was studied with particular reference to cardiolipin and oxidative phosphorylation. Five groups of male weanling rats were fed diets containing 20% (w/w) peanut oil (PO), partially hydrogenated peanut oil (HPO), partially hydrogenated Norwegian capelin oil (HCO), partially hydrogenated herring oil (HHO), and rapeseed oil (RSO) for 10 weeks. All the cardiac phospholipids investigated were influenced by the experimental diets. An increased amount of arachidonic acid observed in phosphatidylethanolamine (PE) after feeding partially hydrogenated oils suggests a changed regulation of the arachidonic acid metabolism in comparison with PO treatment. 22∶1 originating from the dietary oils was incorporated only to a small extent into phosphatidylcholine (PC) and PE. A selective incorporation of 18∶1 isomers into the 1‐ and 2‐positions of PC and PE with respect to geometry and position of the double bond was observed. Large amounts of 18∶1trans were incorporated into the 1‐position of PC and PE, irrespective of the amount of 18∶2 supplemented to the diets, replacing a considerable proportion of stearic acid in this position. After feeding HHO and RSO, the content of 22∶1 in mitochondrial cardiolipin of rat heart was found to be 3% (mainly cetoleic acid) and 10% (mainly erucic acid), respectively, indicating a high affinity forcis isomers of 22∶1, but also a considerable resistance against incorporation oftrans isomers was observed. The ability of rat cardiac mitochondria to oxidize palmitoylcarnitine and to synthesize ATP was depressed after feeding HHO and RSO. Dietarycis isomers of 22∶1 seem to have a specific ability to interfere with cardiac ATP synthesis and also to alter the fatty acid composition of cardiolipin of rat heart.
Photosensitized oxidation of methyl linoleate monohydroperoxides: Hydroperoxy cyclic peroxides, dihydroperoxides, keto esters and volatile thermal decomposition products
Authors: Neff W. E. , Frankel E. N. , Selke E. , Weisleder D.
Published: December 2006

Previous studies of lipid secondary oxidation products have been extended to 6‐membered hydroperoxy cyclic peroxides from the singlet oxygenation of a mixture of 9‐ and 13‐hydroperoxides from autoxidized methyl linoleate. The oxidation product was fractionated by silicic acid chromatography with diethyl ether/hexane mixtures, and selected fractions were separated by polar phase high performance liquid chromatography. Products characterized by thin layer chromatography, gas liquid chromatography, ultraviolet, infrared, nuclear magnetic resonance and mass spectrometry included: 6‐membered cyclic peroxides (13‐hydroperoxy‐9,12‐epidioxy‐10‐ and 9‐hydroperoxy‐10,13‐epidioxy‐11‐octadecenoates), dihydroperoxides (8,13‐ and 9,14‐dihydroperoxyoctadecadienoates) and keto dienes (9‐ and 13‐oxooctadecadienoates). The 6‐membered hydroperoxy cyclic peroxides are apparently formed by 1,4‐addition of singlet oxygen to 9‐ and 13‐hydroperoxides withtrans, trans‐conjugated diene systems. Thermal decomposition of the 6‐membered hydroperoxy cyclic peroxides at 200 C produced methyl 9‐oxononanoate and hexanal as the major volatiles. Other volatiles included 2‐pentylfuran, pentane, 4‐oxo‐2‐nonenal, methyl furanoctanoate and methyl 9,12‐dioxo‐10‐dodecenoate.
Covalent binding of peroxidized linoleic acid to protein and amino acids as models for lipofuscin formation
Authors: Shimasaki Hiroyuki , Ueta Nobuo , Privett O. S.
Published: December 2006

The fluorescent substances produced by the reaction of linoleic acid hydroperoxides (LOOH) with ca. 20 different amino acids and bovine serum albumin (BSA) were studied. Only the amino acids, lysine, glycine, arginine, histidine and phenylalanine, gave products with strong fluorescent properties. Products of lysine had a fluorescence intensity of ca. 10 times those of glycine and 100 times those of phenylalanine. The N‐acylation of amino acids greatly reduced the fluorescence of the products of the reaction except lysine and arginine. The fluorescence of the products of the reaction of LOOH with N‐acetyl BSA was only ca. 25% of the control BSA under the same conditions. It appeared that the substances formed from the reaction of LOOH with BSA were crosslinked polymers as evidenced by column chromatography and polyacrylamide gel electrophoresis. These products were insoluble in common organic solvents and their fluorescent intensities correlated well with the thiobarbituric acid (TBA) test. These observations appear to be highly important in the formation of lipofuscin substances, particularly those associated with the aging pigments which accumulate during aging in mammalian tissues.
Quantitative analysis of lipid classes by liquid chromatography via a flame ionization detector
Authors: Phillips F. C. , Erdahl W. L. , Privett O. S.
Published: December 2006

A method is described for the direct quantitative analysis of the lipid classes of mammalian tissue lipids using high performance liquid chromatography (HPLC) with a flame ionization detector (FID). The lipid is extracted from the tissue with chloroform/methanol after deactivation of hydrolytic enzymes and removal of nonlipid substances by extraction with hot dilute acetic acid (0.05N). Separation of the lipid classes is performed with a column (45 cm × 0.2 cm id) of 8 μm silica (Spherisorb, Phase Sep, Hauppague, NY) treated with concentrated ammonium hydroxide at a solvent flow rate of 0.5 ml/min, which requires a pressure of ca. 900 psi. Cholesteryl esters (CE) and triglycerides (TG) are eluted first with Skellysolve B/methylene chloride (1∶1, v/v); cholesterol (CH) is eluted with chloroform/methylene chloride (1∶2, v/v) and the phospholipids with methanol containing 6% ammonium hydroxide added to the latter solvent in a linear gradient. The neutral lipids are eluted in ca. 12 min and the phospholipids in an additional 30 min. The relative amount of each lipid class was determined from standard curves of the peak areas obtained according to response factors using erucyl alcohol as an internal standard. The method was applied to samples of kidney, liver and serum of rats. Duplicate analyses were generally within ca. 1.0% and good agreement was obtained in the analysis of the lipid classes of Azolectin and liver mitochondria lipid compared to thin layer chromatography (TLC) via photodensitometry of charred spots or phosphorus analysis of recovered phospholipids.
Metabolism of arachidonic acid in leukocytes: Isolation of a 5,15‐dihydroxy‐eicosatetraenoic acid
Authors: Borgeat Pierre , Picard Serge , Drapeau Jean , Vallerand Pierre
Published: December 2006

A novel metabolite of arachidonic acid was isolated from incubations of peripheral blood leukocytes with the fatty acid and the ionophore A23187. The compound was purified by high performance liquid chromatography and identified by ultraviolet photometry and gas chromatography‐mass spectrometry as a 5,15‐dihydroxy‐6,8,11,13‐eicosatetraenoic acid. The compound was also isolated from incubations of human leukocytes with the 15S‐hydroperoxy‐5,8,11,13(Z,Z,Z,E)‐eicosatetraenoic acid, suggesting a double dioxygenation mechanism in the formation of this new metabolite of arachidonic acid. A 5S,15S‐dihydroxy‐6,8,11,13(E,Z,Z,E)‐eicosatetraenoic acid was obtained from incubations of 5S‐hydroxy‐6,8,11,14(E,Z,Z,Z)‐eicosatetraenoic acid with the soybean lipoxygenase and reduction with stannous chloride, and was used as reference compound.
Fatty acid chain length combinations in ascitic fluid triglycerides containing lymphatic absorbed medium‐chain fatty acids
Authors: Christophe A. , Verdonk G. , Mashaly M. , Sandra P.
Published: December 2006

Information on the fatty acid chain length combinations in lymph triglycerides containing medium‐chain fatty acids was obtained combining the fatty acid composition and the carbon number composition of triglycerides from ascitic fluid of patients on medium‐chain triglyceride‐containing diets. In these triglycerides, the major part of the medium‐chain fatty acids was present in combination with long‐chain fatty acids. These results indicate that part of the lymphatic absorbed medium‐chain fatty acids are absorbed as triglycerides which also contain long‐chain fatty acids.
Enzymatic hydrolysis in vitro of thermally oxidized sunflower oil
Authors: Yoshida Hiromi , Alexander J. C.
Published: December 2006

The hydrolysis of thermally oxidized sunflower oil by pancreatic lipase was studied in relation to chemical changes in the acylglycerols. Four classes of compounds (monomers, dimers, trimers and polymers) formed from the acylglycerols were separated from the heated oils by column chromatography on silica gel, and further verified by thin layer chromatography. Each fraction, after analyses for generaly properties, was subjected to a time course study of hydrolysis by pancreatic lipase over a 30‐min period. After 70 hr of heating, the amount of hydrolysis for the acylglycerol dimers was only about half that of the monomers, and that for the trimers was, in turn, about one‐third that of the monomers. The polymers were the least hydrolyzed and showed no further reaction after 5 min. The reduction in enzymatic hydrolysis of isolated fractions from the thermally oxidized oils indicates structural differences, related to formation of polar compounds and polymerization products. Adverse effects on animals from feeding these materials can be attributed partly to inhibition of hydrolysis resulting in less available energy.
Digitonin‐precipitable sterols as a measure of cholesterol biosynthesis: Contradictory results
Authors: Tabacik C. , Aliau S. , Crastes de Paulet A.
Published: December 2006

In experiments with 4 different types of cells, we evaluated the cholesterogenic activity by incorporation of14C‐acetic acid into cholesterol and digitonin‐precipitable sterols. In every case, the cholesterogenesis appeared considerably faster when expressed as digitonid than when expressed as real cholesterol production, and sometimes the data obtained by the 2 methods were contradictory. Detailed analysis of both digitonid components and nonprecipitable radioactive metabolites showed that a very variable fraction of methyl sterols (including bifunctional methyl sterols) co‐precipitates with the C‐27 sterols. In cholesterol regulation studies and particularly when the cells exhibit a low cholesterogenesis, the digitonin method is unsuitable and can lead to erroneous interpretations.
The effect of vitamin C on in vivo lipid peroxidation in guinea pigs as measured by pentane and ethane production
Authors: Kunert Karl‐Josef , Tappel Al. L.
Published: December 2006

Measurements of pentane and ethane as indices of in vivo lipid peroxidation were made on samples of breath from vitamin C‐sufficient and vitamin C‐deficient guinea pigs injected with 23 μl carbon tetrachloride (CCl4)/100 g body wt. Vitamin C‐deficient animals produced significantly more pentane and ethane after CCl4 treatment than did vitamin C‐sufficient guinea pigs. Pretreatment of vitamin C‐deficient animals with 75 mg ascorbic acid/100 g body wt significantly lowered both pentane and ethane evolution. Protection against in vivo lipid peroxidation similar to that provided by ascorbic acid was also found when vitamin C‐deficient guinea pigs were pretreated with isoascorbic acid, reduced glutathione, α‐tocopherol or β‐carotene. When animals were pretreated with the radical scavenger mannitol, a protective effect was also observed as measured by pentane evolution.
Severe fatty liver in rats fed a fat‐free ethanol diet, and its prevention by small amounts of dietary arachidonate
Authors: Goheen Steven C. , Larkin Edward C. , Rao G. Ananda
Published: December 2006

Rats were fed ethanol and a fat‐free diet for 30 days to determine whether dietary fat is needed for the development of fatty liver. The severity of fatty liver was similar to that of rats fed an isocaloric diet with 35% fat. Small amounts (29 mg/day) of dietary arachidonic acid prevented alcoholic fatty liver. Rats fed either the alcohol (AF) or control (CF) fat‐free diets developed essential fatty acid deficiency (EFAD) as measured by the triene/tetraene ratio of liver and plasma lipids. Rats fed arachidonic acid (AA, alcohol and CA, control diets) did not develop EFAD. Although EFAD alone did not cause the development of fatty liver, the combination of dietary ethanol and EFAD did. The ratios of 16∶1/16∶0 and 18∶1/18∶0 in liver lipids indicated that desaturase enzymes were less active and lipogenesis was reduced in rats fed the AA diet compared to those fed the AF diet. In contrast, stimulated lipogenesis appears to have been the cause of fatty liver in rats fed the AF diet.
Potentiating effect of 5,8,11‐eicosatrienoic acid on human platelet aggregation
Authors: Lagarde M. , Burtin M. , Sprecher H. , Dechavanne M. , Renaud S.
Published: December 2006

5,8,11‐Eicosatrienoic acid (20∶3ω9), a fatty acid increased in the platelet phospholipids of man and animals fed saturated fats, was either added to human platelets simultaneously with the aggregating agents, or incorporated into the platelet phospholipids by preincubation. 20∶3ω9 markedly increased the response of platelets to all aggregating agents tested when added simultaneously with the agent, but solely to thrombin and ionophore, after incorporation into the platelet phospholipids. The potentiating effects of 20∶3ω9 on thrombin aggregation do not appear to be related to prostaglandin formation, but rather to the production of a monohydroxy derivative through the lipoxygenase pathway.
Distribution of the molecular species of phospholipids in human umbilical cord blood
Authors: Breckenridge W. Carl , Dolphin Peter J. , Tan Meng H.
Published: December 2006

The composition of phosphatidylcholine (PC) and sphingomyelin (SM) was studied in cord blood lipoproteins to determine whether equilibration of the molecular species of phospholipids among lipoproteins was comparable with that reported for adults. The molecular species distributions of PC in low density lipoprotein (LDL) differed from that of high density lipoprotein (HDL). Whereas LDL PC was richer in combinations of fatty acids with 16 and 18 carbon atoms than HDL, the HDL was markedly enriched in combinations of fatty acids with 18 and 20 carbon atoms. Sphingomyelins in LDL were richer in palmitic acid than HDL while HDL had a greater proportion of long chain sphingomyelin than LDL. The molecular species of PC and SM do not equilibrate in cord blood. The results for the SM distributions were similar to other reports for adult human lipoprotein. However, the marked differential distribution of PC among lipoproteins appears unique to cord blood. The mechanisms responsible for equilibrating PC among lipoproteins are less well developed in the neonate when compared with the adult.
In vitro and in vivo effects of ethanol on the formation of endoperoxide metabolites in rat platelets
Authors: Hwang Daniel H. , LeBlanc P. , Chanmugan P.
Published: December 2006

Preincubation of rat platelet‐rich plasma (PRP) with ethanol resulted in dose‐dependent inhibition of the formation of endoperoxide metabolites (EPM) when the PRP was aggregated by collagen suspension. The inhibition was manifested at concentrations normally attainable in blood of rats or humans by tolerable amounts of ethanol ingestion. Paradoxically, chronic ingestionof ethanol caused enhanced synthesis of EPM in platelets, indicating that the inhibitory effect of ethanol would be temporary, and that it can be reversed as soon as ethanol is eliminated. The level of arachidonic acid in platelet phospholipids of rats fed the ethanol diet was not different from that of the control, indicating that availability of immediate precursor acid would not be a factor for the enhanced synthesis of EPM in the ethanol group. This result suggested that platelets from rats subjected to chronic ethanol ingestion become hyperactive in synthesizing EPM through an unknown mechanism. When citrated whole blood was incubated in the presence of collagen suspension, amounts of EPM synthesized in the ethanol group were not different from those of the control group, but this was due to significant reduction of platelet counts in the ethanol group. whether the effect of ethanol on other tissues would be similar to that on platelets is unknown. It is tempting to speculate that some of the pathological changes resulting from alcoholism might be mediated through the effect of ethanol on EPM formation.
The synthesis in vivo of choline and ethanolamine phosphoglycerides in different brain areas during aging
Authors: Gaiti Alberto , Brunetti Marina , Piccinin Gian Luigi , Woelk Helmut , Porcellati Giuseppe
Published: December 2006

The biosynthesis of choline and ethanolamine phosphoglycerides was tested in vivo in different brain areas of the rat during aging. Mixtures of [2−3H] glycerol and [Me‐14C] choline or [2‐3H] glycerol and [2‐14H] ethanolamine were injected into lateral ventricle of the brain as lipid precursors and their incorporation into corresponding phospholipid was examined. A significant decrease of synthesis of both phosphoglycerides takes place in cerebral cortex and in the striatum, and is already apparent at 9 months of age with no further decrease or change therafter. No significant change takes place in the cerebellum. The unchanged absorption of injected water‐soluble precursors, together with the lack of any significant change of phospholipid/protein ratio in all examined brain areas, suggests that the incorporation of both glycerol and nitrogen bases are affected by aging.
Relationships between levels of essential fatty acids and zinc in plasma of cystic fibrosis patients
Authors: Hamilton R. M. , Gillespie C. T. , Cook H. W.
Published: December 2006

Possible relationships between zinc and essential fatty acid metabolism have been assessed using plasma samples obtained from 39 cystic fibrosis patients. The fatty acid composition of plasma phospholipids was analyzed by capillary gas liquid chromatography and zinc levels were measured by atomic absorption spectrometry. Computer analyses revealed positive correlations between zinc levels and (a) arachidonic acid (P<0.001), (b) the arachidonate/linoleate ratio (P<0.02), and (c) eicosatrienoic acid (n−6) (P<0.001). These observations suggest that conversion of linoleate to arachidonate may be modulated by zinc.
Hypolipidemic effects of clofibrate and selected chroman analogs in fasted rats: I. Chow‐fed animals
Authors: O'Brien M. , Patel S. T. , Mukhopadhyay A. , Newman H. A. I. , Feller D. R. , Kokrady S. S. , Witiak D. T. , Lanese R. R. , Rice J. C.
Published: December 2006

The hypolipidemic properties of ethyl 6‐chlorochroman‐2‐carboxylate (II), ethyl 6‐phenylchroman‐2‐carboxylate (III) and ethyl 6‐cyclohexylchroman‐2‐carboxylate (IV) were compared to clofibrate (I) in fasted normolipidemic rats. The chroman analog II, like its parent compound, clofibrate, reduced serum and α‐lipoprotein cholesterol concentrations. Although analog III had no effect on serum cholesterol, it caused a slight elevation of α‐lipoprotein cholesterol concentration. Serum free cholesterol was increased and LCAT activity was reduced in clofibrate‐treated rats. The hypolipidemic agents had no consistent effect on liver lipid concentrations and liver microsomal HMG‐CoA reductase activity. In addition, we have shown that drug efficacies varied directly with seasonal variations in serum lipid concentrations.
Lethal effect ofcis‐ but nottrans‐22‐dehydrocholesterol on mouse fibroblast cells
Authors: Kircher Henry W. , Rosenstein Fumiko U. , Kandutsch Andrew A.
Published: December 2006

cis‐ andtrans‐22‐dehydrocholesterol were incorporated into the culture medium for mouse fibroblast cells. Although neither isomer had an effect on sterol biosynthesis, thecis isomer inhibited cell growth and viability and increased Rb+ efflux from the cells. Thetrans isomer had no effect on growth and could replace exogenous cholesterol for growth of cells for which sterol biosynthesis was blocked by 25‐hydroxycholesterol.
Ether lipid content and fatty acid distribution in rabbit polymorphonuclear neutrophil phospholipids
Authors: Mueller Howard W. , O'Flaherty Joseph T. , Wykle Robert L.
Published: December 2006

This study was undertaken to determine if rabbit neutrophils contain sufficient ether‐linked precursor for the synthesis of 1‐O‐alkyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine (platelet activatin factor) by a deacylation‐reacylation pathway. The phospholipids from rabbit peritoneal polymorphonuclear neutrophils were purified and quantitated, and the choline‐containing and ethanolamine‐containing phosphoglycerides were analyzed for ether lipid content. Choline‐containing phosphoglycerides (37%), ethanolamine‐containing phosphoglycerides (30%), and sphingomyelin (28%) were the predominant phospholipid classes, with smaller amounts of phosphatidylserine (5%) and phosphatidylinositol (<1%). The choline‐linked fraction contained high amounts of 1‐O‐alkyl‐2‐acyl‐(46%) and 1,2‐diacyl‐sn‐glycero‐3‐phosphocholine (54%), with a trace of the 1‐O‐alk‐1′‐enyl‐2‐acyl species. The ethanolamine‐linked fraction contained high amounts of 1‐O‐alk‐1′‐enyl‐2‐acyl‐(63%) and 1,2‐diacyl‐sn‐glycero‐3‐phosphoethanolamine (34%), and a low quantity of the 1‐O‐alkyl‐2‐acyl species (3%). The predominant 1‐O‐alkyl ether chains found in thesn‐1 position of the choline‐linked fraction were 16∶0 (35%), 18∶0 (14%), 18∶1 (26%), 20∶0 (16%), and 22∶0 (9%). The major 1‐O‐alk‐1′‐enyl ether chains found in thesn‐1 position of the ethanolamine‐linked fraction were 14∶0 (13%), 16∶0 (44%), 18∶0 (27%), 18∶1 (12%) and 18∶2 (3%). The major acyl groups in thesn‐1 position of 1,2‐diacyl‐sn‐glycero‐3‐phosphocholine and 1,2‐diacyl‐sn‐glycero‐3‐phosphoethanolamine were 16∶0, 18∶0 and 18∶1. The most abundant acyl group in thesn‐2 position of all classes of choline‐ and ethanolamine‐linked phosphoglycerides was 18⩺2. Although this work does not define the biosynthetic pathway for platelet activating factor, it does show that there is ample precursor present to support its synthesis by a deacylation‐reacylation pathway.
High performance reversed‐phase chromatography of the triglycerides from human plasma lipoproteins
Authors: Perkins E. G. , Hendren David J. , Pelick Nicholas , Bauer John E.
Published: December 2006

The triglycerides of human plasma lipoproteins were separated with high performance reversed‐phase liquid chromatography. An octadecyl bonded 5‐μ silica column was used with a mobile phase of acetonitrile/acetone. Individual triglyceride types and critical pairs may be easily separated and identified.
The metabolism of lithocholic acid and lithocholic acid‐3‐α‐sulfate by human fecal bacteria
Authors: Borriello S. P. , Owen R. W.
Published: December 2006

Both lithocholic acid and lithocholic acid‐3α‐sulfate are metabolized by mixed fecal bacteria and by pure strains of the genusClostridium. Mixed fecal bacteria metabolized lithocholic acid to 3‐ketolithocholic acid; lithocholic acid‐3α‐sulfate was metabolized to isolithocholic acid, 5β‐cholanic acid and Δ3‐cholenic acid under both aerobic and anaerobic conditions. The results indicate that a specific genus, theClostridium, has a primary role in the metabolism of lithocholic acid‐3α‐sulfate to Δ3‐cholenic acid
Plasma high density lipoprotein subgroup distribution in rats fed diets with varying amounts of sucrose and sunflower oil
Authors: Høstmark Arne T. , Spydevold Øystein , Lystad Einar , Kristensen Eva , Bay Ida Goffeng
Published: December 2006

The effect of varying the dietary sunflower oil/sucrose (SO/SU) ratio on rat plasma lipid concentration and lipoprotein distribution was studied. Four groups of 10 rats were fed for 4 weeks diets with varying SO/SU ratios. Lipoprotein components were then estimated in whole plasma and after cumulative density ultracentrifugation. Whole plasma triacylglycerol (TG), total cholesterol (TC) and free cholesterol (FC) decreased with increasing SO/SU ratio; the CE/FC ratio increased, because CE remained virtually unaltered. Plasma TG‐lowering was due to a decrease in VLDL and LDL‐TG. Protein, CE and FC in d=1.063–1.100 g/ml (HDL2b) and d=1.100–1.125 g/ml (HDL2a) lipoproteins decreased upon increasing the SO/SU ratio. In contrast, in d=1.125–1.200 g/ml (HDL3) lipoproteins, there was a concomitant increase in these components. Although increasing the SO/SU ratio effected more protein and CE transportation in HDL3 and less in HDL2, the total amount of these components in high density lipoproteins (d=1.063–1.200 g/ml) remained constant. Apo A‐I and apo C‐III decreased in HDL2 but increased in HDL3 upon increasing the SO/SU ratio. Also, HDL2 apo E, and the apo C‐II/apo C‐III and small apo B/large apo B ratios in VLDL and LDL were lowered by increasing the SO/SU ratio. The hepatic VLDL‐TG output during isolated liver perfusion was lowest in rats fed the diet with the highest SO/SU ratio. In perfusate, like in plasma, the VLDL and LDL apo C‐II/apo C‐III ratio, as well as the small apo B/large apo B ratio, decreased upon increasing the dietary SO/SU ratio. The results indicate that there can be appreciable diet‐dependent variations in plasma HDL subgroup distribution in spite of unchanged total HDL levels.
Effect of age and cholestyramine feeding on rat liver 3‐hydroxy‐3‐methyl glutaryl CoA reductase, sterol carrier protein 1 and sterol carrier protein 2 activities
Authors: Morin Robert J. , Brun Michael J. , Srikantaiah M. V.
Published: December 2006

The rate of formation of sterol from squalene in livers from suckling rats was less than one‐third that of adults. This difference was due to a lesser activity of microsomal enzymes in the suckling rat livers, and not to any difference in cytosolic sterol carrier protein 1. The microsomal enzymes and sterol carrier protein 2 of the cytosol required for the conversion 7‐dehydrocholesterol to cholesterol were both lower in suckling rats compared to adults. Both those activities paralleled the differences in HMG‐CoA reductase activities between suckling and adult rats. Feeding of cholestryamine to adult rats increased the activities of the microsomal enzymes, sterol carrier protein 1 and sterol carrier protein 2 involved in the conversion of squalene to cholesterol.