bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linolenic acid deficiency
Authors: Tinoco J. , Babcock R. , Hincenbergs I. , Medwadowski B. , Miljanich P. , Williams M. A. 
Published: November 2006

AbstractLinolenic acid deficiency has not been demonstrated clearly in warm blooded animals, yet circumstantial evidence suggests that n−3 fatty acids may have functions in these animals. The fact that several species of fish definitely require dietary n−3 fatty acids indicates that n−3 fatty acids have important and specific functions in these animals and suggests that such functions may also be present in warm blooded animals. It is also true that n−3 fatty acid distribution in tissues of birds and mammals appears to be under strict metabolic control, and that this complex metabolic control mechanism apparently has survived evolutionary pressure for a very long time. So far, attempts to produce linolenic acid deficiency in mammals have not revealed an absolute requirement for n−3 fatty acids. If functions for n−3 fatty acids do exist in warm blooded animals, it seems probable that they may be located in the cerebral cortex or in the retina, because these tissues normally contain high concentrations of n−3 fatty acids.
Polyunsaturated fatty acids, vitamine E, and the proliferation of aortic smooth muscle cells
Authors: Cornwell David G. , Huttner James J. , Milo George E. , Panganamala R. V. , Sharma H. M. , Geer Jack C. 
Published: November 2006

AbstractSmooth muscle cell cultures were obtained from the aortas of prepubertal guinea pigs. Cell proliferation in these cultures was inhibited by 8,11,14‐eicosatrienoic acid, 5,8,11,14‐eicosatetraenoic acid, and their prostaglandin E derivatives, PGE1 and PGE2. Prostaglandin F derivatives, PGF1α and PGF2α, stimulated cell proliferation. Cell proliferation was also inhibited by 5,8,11‐eicosatrienoic acid and 11,14,17‐eicosatrienoic acid. The monoene and diene precursors of the triene acids, 9‐octadecenoic acid and 9,12‐octadecadienoic acid, did not inhibit cell, proliferation. Indomethacin alone had no effect on cell proliferation, and indomethacin did not suppress the inhibition of cell proliferation with a triene acid. The antioxidant α‐naphthol alone stimulated cell proliferation and suppressed prostaglandin E formation. α‐Naphthol in the presence of either triene or tetraene acids also stimulated cell proliferation and suppressed prostaglandin E formation. The antioxidants butylated hydroxy toluene and 6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid either alone or in the presence of triene and tetraene acids stimulated cell proliferation and had no effect on prostaglandin E formation. Vitamin E either alone or in the presence of triene or tetraene acids stimulated cell proliferation and had no effect on prostaglandin E formation. More prostaglandin E was formed from 8,11,14‐eicosatrienoic acid than from 5,8,11,14‐eicosatetraenoic acid in the presence of antioxidants. Vitamin E suppressed the inhibitory effects of both PGE2 and palmitic acid on cell proliferation. The cyclic nucleotide phosphodiesterase inhibitors, caffeine and papaverine, suppressed the stimulatory effect of vitamin E on cell proliferation and enhanced the inhibitory effect of a triene acid on cell proliferation. Substrate and inhibitor specificities are consistent with the oxidative regulation of cell proliferation through the formation of hydroperoxy fatty acids. We propose that hydroperoxy fatty acids may regulate both cyclase and cyclic nucleotide phosphodiesterase enzymes through sulfhydryl‐disulfide interconversions. We suggest that this regulatory mechanism may help to explain the acculation of 5,8,11‐eicosatrienoic acid in essential fatty acid deficiency, the effects of antioxidants on cell proliferation, and one of the several effects of polyunsaturated fatty acids in proliferative disorders such as cancer and atherosclerosis.
The effect of isomerictrans‐18∶1 acids on the desaturation of palmitic, linoleic and eicosa‐8,11,14‐trienoic acids by rat liver microsomes
Authors: Mahfouz M. M. , Johnson S. , Holman R. T. 
Published: November 2006

AbstractThe inhibitory effects of the positional isomers oftrans‐18∶1 acids on the desaturation of palmitic acid to palmitoleic (Δ9‐desaturase), linoleic to γ‐linolenic (Δ6‐desaturase) and eicosa‐8,11,14‐trienoic to arachidonic acid (Δ5‐desaturase) were investigated. Thesetrans‐18∶1 acids were found to be inhibitory for the microsomal Δ6‐, Δ9‐ and Δ5‐desaturases of rat liver. The position of the double bond in thetrans‐18∶1 acids seems to be important in determining the degree of inhibition. At inhibitor/substrate ratio of 3∶1, the Δ6‐desaturase was most strongly inhibited bytrans‐Δ3,‐Δ4,‐Δ7 and‐Δ15‐18∶1 isomers, whereas the Δ9‐desaturase was most strongly inhibited bytrans‐Δ3,‐Δ5,‐Δ7,‐Δ10,‐Δ12,‐Δ13 and‐Δ16 isomers. At inhibitor/substrate ratio of 6∶1, the Δ5‐desaturase was most strongly inhibited by Δ3‐, Δ9‐, Δ13‐ and Δ15‐isomers. When 18∶0 was added to the incubations of 16∶0, 18∶2 and 20∶3 at the same I/S ratios used for thetrans‐18∶1 acids, weak inhibition for Δ9‐desaturase and no inhibition for Δ5‐and Δ6‐desaturases was observed.
Lipoprotein lipid and protein synthesis in experimental nephrosis and plasmapheresis. I: Studies in rat in vivo
Authors: Shafrir Eleazar , Brenner Talma 
Published: November 2006

AbstractThe incorporation of L‐4,5‐[3H]leucine into the ultracentrifugally separated apolipoproteins of very low, low, and high density lipoproteins (VLDL, LDL, HDL) and into serum albumin was found three‐to four‐fold higher in nephrotic than in normal rats one hour after intravenous injection. Incorporation of leucine into the circulating lipids was negligible. Increases of similar magnitude were obtained in the incorporation of simultaneously injected 1,5[14C] citrate into the lipids of VLDL, LDL, and HDL of nephrotic rats. Of the citrate carbons incorporated into serum and liver lipids, the proportion in cholesterol was higher in nephrotic rats when compared to normal rats. The incorporation of both precursors into total proteins and lipids of the liver vs. the incorporation into the lipoproteins was relatively lower in nephrotic than in control rats, indicating a preferential channeling into secretable products. The occurrence of enhanced new lipid synthesis in nephrosis was corroborated by the finding of markedly enhanced synthesis of lipoprotein‐borne fatty acids and cholesterol from3H2O. These results point out that while leucine is not an efficient in vivo precursor of lipoprotein lipids in nephrosis, de novo lipogenesis proceeds from other precursors. Similar trend of changes, though of smaller magnitude, was elicited in rats after double plasmapheresis, 18 hr apart, when measured 3 hr after the second plasma withdrawal. This indicates that the loss of circulating proteins either by direct removal or through kidney lesion stimulates the compensatory hepatic response involving excessive lipoprotein synthesis. Time‐course studies showed that peak incorporation of leucine and citrate into the protein and lipid components of lipoproteins, respectively, as well as into serum albumin, occurred coincidentally 3 hr after the second plasmapheresis, suggesting an interdependence of the enhanced protein and lipid synthesis.
Phospholipid metabolism inNeisseria gonorrhoeae: Phospholipid hydrolysis in nongrowing cells
Authors: Cacciapuoti Anthony F. , Wegener Warner S. , Morse Stephen A. 
Published: November 2006

AbstractHydrolysis of cell envelope phospholipids was demonstrated in cells of both autolytic and nonautolytic strains ofNeisseria gonorrhoeae that were labeled during growth in the presence of [3H] acetate. The label incorporated into the cellular phospholipids was located exclusively in the fatty acid acyl side chains. Labeled cells were incubated for 2 hr in N‐2‐hydroxyethylpiperazine‐N′‐2‐ethanesulfonic acid buffer, pH 8.5, containing various additions, and then examined for distribution of3H in lipids. Ca++ selectively stimulated the deacylation of phosphatidylethanolamine (PE), whereas Mn++ stimulated the deacylation of phosphatidylglycerol (PG). Hydrolysis of phosphatidylethanolamine by phospholipase A was accompanied by the accumulation of lysophosphatidylethanolamine (LPE) and free fatty acids in the cells. Free fatty acids accumulated to a greater extent than lysophosphatidylethanolamine, suggesting that the latter was further hydrolyzed to glycerophosphorylethanolamine (GPE) and free fatty acids by a lysophospholipase. Methanol, ethanol, propanol, and isopropanol, added at concentrations which inhibited growth by 50%, stimulated phospholipase A, but not lysophospholipase activity. Differences in heat inactivation, metal ion requirements, and pH optima suggested that phospholipase A activities with phosphatidylethanolamine or phosphatidylglycerol as substrate and lysophospholipase may be separate enzymes.
Thermal alteration of a cyclic fatty acid produced by a flaxseed extract
Authors: Vick Brady A. , Zimmerman Don C. , Weisleder David 
Published: November 2006

AbstractMethyl 8‐[2‐(cis‐pent‐2′‐enyl)‐3‐oxo‐cis‐cyclopent‐4‐enyl] octanoate (I) is the methyl ester of a cyclic fatty acid synthesized enzymically from an incubation of linolenic acid with an extract of flaxseed (Linum usitatissimum L.). A proposed trivial name for I is methyl 12‐oxo‐cis‐10, 15‐phytodienoate (12‐oxo‐PDA). The evidence presented indicated that compound I has thecis configuration of the carbon chains with respect to the cyclopentenone ring. Treatment with acid, base, or heat isomerized I to a second product (II) that has thetrans configuration of the carbon chains. Prolonged heat treatment of II yielded a third cyclic product, methyl 12‐oxo‐9(13),cis‐15‐phytodienoate (III).
A specific spectrophotometric determination of long chain nitro compounds and its application to NO2‐initiated lipid autoxidation
Authors: Collard Randle S. , Pryor William A. 
Published: November 2006

AbstractA specific spectrophotometric method is described for the determination of nitro‐β‐hydroperoxides produced during the initiation of lipid autoxidation by ppm NO2; this determination provides a measure of the rate of initiation by addition of NO2 to lipids. The nitro group is reduced to an amine using polymethylhydrosilane (PMHS) and Pd on charcoal, and the amine is then determined spectrophotometrically as a neutral methyl orange salt. Although this method was developed for the determination of micromolar quantities of nitro‐β‐hydroperoxides in lipid samples, it can be used to determine any long chain, nonpolar nitro compound. The method also can be adapted to allow the determination of polar or short chain nitro compounds by using a different amine determination.
Continuous spectrophotometric assay of conjugated bile acid hydrolase
Authors: Kirby Lyndon C. , Klein Robert A. , Coleman James P. 
Published: November 2006

AbstractConjugated bile acid hydrolase (CBAH) refers to a class of enzymes which catalyze the cleavage of the amino acid moieties from conjugated bile acids. These enzymes are significant because of their role in providing substrates for further microbial metabolism in the gastrointestinal tract. They also are used in research laboratories for the deconjugation of bile acids prior to structural analyses. A continuous spectrophotometric assay for CBAH activity was developed using a conjugate of cholic acid and the chromophore, 5‐amino‐2‐nitro‐benzoic acid. The free chromophore is detected by virtue of its absorbance at 410 nm. The CBAH fromClostridium perfringens displayed aKm for this substrate of 120 μM. These results demonstrate that this new compound functions as an effective substrate of the enzyme and forms the basis for a convenient and rapid method to monitor CBAH activity.
Use of gas chromatography/isotope ratio‐mass spectrometry to study triglyceride metabolism in humans
Authors: Binnert C. , Laville M. , Pachiaudi C. , Rigalleau V. , Beylot M. 
Published: November 2006

AbstractThe study of triglyceride (TG) metabolism using stable isotope tracers would be facilitated by being able to detect low13C enrichment. To meet this goal, we developed a gas chromatography/isotope ratio‐mass spectrometry technique to measure the enrichment of palmitate in nonesterified fatty acids (NEFA) and TG as its methyl derivative. This method allows accurate and reproducible measurements of enrichment as low as 0.009 mole percent excess (MPE), in a range between 0–0.65 MPE. The usefulness of this method is shown by two studies of lipid metabolism in human beings. First, we studied the metabolic fate of an oral TG load labeled with [1,1,1‐13C3]tripalmitin. Labeled palmitate appeared concurrently in plasma NEFA and TG, and four hours after the load, the labeling was higher in NEFA than in TG (MPE NEFA: 1.53±0.31 vs. MPE TG: 0.78±0.06,P<0.05). In a second study, the hepatic reesterification of NEFA was estimated by measuring the appearance of infused [1‐13C]palmitate in circulating TG. The estimated contribution of plasma NEFA to circulating TG increased to a maximum of 22%. Thus, gas chromatography/isotope ratio‐mass spectrometry appears to be a useful tool for future studies of lipid metabolism in humans.
Microscale synthesis of phosphatidyl‐[3H]choline from 1,2‐diacylglycerol. Assessment of isomerization by reversed‐phase high‐performance liquid chromatography
Authors: Bugaut Maurice , Gresti Joseph , Gagniarre Jerôme 
Published: November 2006

AbstractThe synthesis ofrac‐1‐palmitoyl‐2‐oleoylglycero‐3‐phospho‐[3H]choline of high specific activity was carried out on a microscale by making 7 μmol ofrac‐1‐palmitoyl‐2‐oleoylglycerol react first with an equimolar amount of POCl3 and then of [3H]choline. After purification by thin‐layer chromatography and normal‐phase high‐performance liquid chromatography (HPLC), the yield of the synthesis of [3H]phosphatidylcholine (120 μCi/μmol) was 22%.rac‐1‐Palmitoyl‐2‐oleoylglycerol was purified before use by reversed‐phase HPLC under conditions which were nonisomerizing and allowed the separation of 1,2‐ and 1,3‐isomers of diacylglycerol. Ethanol, but not benzene, was shown to cause isomerization of long‐chain diacylglycerol and, therefore, was not used for drying the substrate before reaction. A rapid and complete separation of 1,2‐ and 1,3‐isomers of long‐chain phosphatidylcholine was obtained by reversed‐phase HPLC using 20 mM choline chloride in methanol/acetonitrile/water (50∶50∶1, by vol) isocratically as the mobile phase. Under these conditions, analysis of the synthetizedrac‐1‐palmitoyl‐2‐oleoylglycero‐3‐phospho‐[3H]choline showed a total absence of 1,3‐isomer.
Lipid composition ofbacillus megaterium spores and spore membranes
Authors: Nikolopoulou M. , Vary J. C. 
Published: November 2006

AbstractBacillus megaterium QM B1551 spore lipids were extracted by an improved technique, and the phospholipid and fatty acid compositions were determined. Phospholipids accounted for 65% of the total fatty acids; the neutral lipid fraction contained 15% and the remaining fatty acids were in the interphase, aqueous phase and pellet from the lipid extraction. Each phospholipid had similar fatty acid compositions as did the delipidated pellet. However, the aqueous phase and, to some extent, the interphase had unique fatty acid compositions. Also, fatty acids were found acylated to proteins, which was observed by electrophoresis of delipidated proteins from spores grown in [1‐14C]palmitate. Therefore, spores contain unique non‐phosphatide fatty acid components that can now be analyzed.
Characterization of phospholipase A2 from rabbit lung microsomes
Authors: Filgueiras Octávio M. O. , Possmayer Fred 
Published: November 2006

AbstractA phospholipase A2 activity associated with the microsomal fraction of rabbit lung homogenates was studied. The enzyme showed specificity for thesn−2 ester bond of phosphatidylcholine, had an alkaline pH optimum and required Ca2+ for activity. Other divalent cations were unable to support hydrolysis. In the absence of detergents, exogenous phosphatidylethanolamine was deacylated at a rate sevenfold higher than phosphatidylcholine. The activity toward both substrates could be enhanced by sodium deoxycholate or, more effectively, by sodium taurodeoxycholate. Phosphatidylethanolamine required higher detergent/phospholipid molar ratios than phosphatidylcholine. Under these conditions, the preference for the former substrate over the latter was nearly abolished. The zwitterionic detergent 3‐[(3‐cholamidopropyl) dimethylammonio]‐1‐propanesulfonate (CHAPS) and the nonionic detergent Triton X‐100 were either ineffective (phosphatidylcholine) or inhibitory (phosphatidylethanolamine). Addition of KCl produced opposite effects on the activity depending on the bile salt used to disperse the substrate. The phospholipase A2 activity was inhibited byp‐bromophenacyl bromide but remained unaffected after treatment with diisopropylfluorophosphate or NaF. N‐Ethylmaleimide, but not other thiol reagents, partially inhibited the activity.
New findings in the fatty acid composition of individual platelet phospholipids in man after dietary fish oil supplementation
Authors: Mori Trevor A. , Codde James P. , Vandongen Robert , Beilin Lawrence J. 
Published: November 2006

AbstractNine healthy male volunteers were given 15 Max EPA fish oil capsules providing 2.67 g of eicosapentaenoic acid (EPA, 20∶5ω3) and 1.72 g of docosahexaenoic acid (DHA, 22∶6ω3) daily for 3 wk. Measurements were taken at baseline, at the end of the fish‐oil period, and at 2 and 6 wk postsupplementation. The effect of fish oil on plasma lipids and the fatty acid composition of individual platelet phospholipids was studied. In general, the proportions of 20∶5ω3 and 22∶6ω3 in platelet phosphoglycerides were substantially increased mainly at the expense of arachidonic acid (AA, 20∶4ω6). A large and significant increase in the relative EPA content of phosphatidylcholine (PC) (P<0.001) and phosphatidylethanolamine (PE) (P<0.001) was noted at the end of the 3 wk supplementation. We have also shown for the first time a small but significant (P<0.001) incorporation of EPA in phosphatidylserine (PS). Incorporation of DHA was also detected in PC, PE and PS, whereas the relative AA content of these phospholipids was significantly reduced. Fish oil supplementation led to a significant increase of 22∶5ω3 in PS and decreases of 20∶3ω6 in PC and 22∶4ω6 in PE. Postsupplementation measurements showed a gradual return of all fatty acids to baseline levels. The fatty acid composition of the phosphatidylinositol (PI) fraction remained unchanged throughout the trial period. We conclude that in humans ω3 fatty acids are incorporated into platelet membrane phospholipid subclasses with a high degree of specificity.
Immunocytochemical localization of lingual lipase in serous cells of the developing rat tongue
Authors: Roberts Ingram M. , Nochomovitz Lucien E. , Jaffe Ronald , Hanel Selma I. , Rojas Magaly , Agostini R. A. 
Published: November 2006

AbstractThe ontogeny of the rat lingual serous and mucous glands was explored by light and electron immune microscopy using the peroxidase‐antiperoxidase and streptavidin‐gold techniques. Tissues from fetal and neonatal rats from day 18 of gestation through 4 wk after birth were fixed and embedded in paraffin or Epon for light and transmission electron microscopy, respectively. Electron microscopy revealed that the only cells containing lingual lipase were the developing serous cells; secretory granules containing lingual lipase of varying degrees of maturity were seen. Mucous cells did not show immunospecific staining in rats of any age. The neonatal “mixed” lingual glands secrete lingual lipase from serous components immediately after birth to aid in fat digestion.
Mass spectra of the picolinyl esters of isomeric mono‐ and dienoic fatty acids
Authors: Christie W. W. , Brechany E. Y. , Holman R. T. 
Published: November 2006

AbstractThe picolinyl ester derivatives of the complete series of isomeric octadecenoates, methylene‐interrupted octadecadienoates, and of octadec‐9‐ynoate have been subjected to gas chromatography‐mass spectrometry. A fused‐silica capillary column, coated with a cross‐linked methyl silicone, was used for the separation. Electron impact spectra were determined at 70 eV. Earlier observations with a limited series of model compounds were confirmed, and it was shown that the picolinyl ester derivatives were of almost universal value in the location of double bonds in such isomers. Difficulties of interpretation arose mainly when the double bonds were close to the carboxyl group.
Characterization of feline omentum lipids
Authors: McCluer Robert H. , Evans James E. , Williams Marcia , Griffith Ann L. , Catsimpoolas Nicholas 
Published: November 2006

AbstractFeline omental lipid extracts, previously reported to be angiogenic in the cornea of rabbits, were fractionated and the major lipid components characterized. Approximately 97% of the chloroform/methanol extract consisted of triglycerides containing primarily 16∶0, 18∶0, 18∶1 and 18∶2 fatty acids. Trace quantities of free fatty acids, cholesterol, di‐ and monoglycerides were also detected. The phospholipid fraction, obtained by solvent partition and Unisil column chromatography and characterized by high performance liquid chromatography (HPLC)‐mass spectrometry, was found to consist of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine and phosphatidylserine. The neutral glycolipids, isolated by solvent partition and Unisil column chromatography and identified by high performance thin layer chromatography and HPLC of their perbenzoylated derivatives, were found to consist of glucosyl‐ and galactosylceramides, galabiosylceramide, lactosylceramide, globotriaosylceramide and globotetraosylceramide. The complex glycolipid fraction, obtained from Folch upper phase solvent partition, was found to consist primarily of Forssman glycolipid and gangliosides GM3 and GD3. Smaller amounts of GM1 and other unidentified gangliosides were also present.