bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of borage oil consumption on the composition of individual phospholipids in human platelets
Authors: Barre D. Edward , Holub Bruce J. 
Published: November 2006

AbstractThe effect of supplementation with borage oil containing γ‐linolenic acid (GLA, 18∶3n−6) on the levels and fattya cid compositions of individual human platelet phospholipids was evaluated. For this purpose, male volunteers were given an average daily intake of 5.23 g of GLA (as borage oil) for 42 days, after which the supplement was withdrawn for an additional 42‐day period. No significant differences were found in the relative amounts of the choline phospholipids (PC), ethanolamine phospholipids (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and sphingomyelin (SPH) at days 0, 22, 43, 64, and 85. However, marked differences were observed in the fatty acid compositions of all the phospholipids including a marked, and reversible, rise in the level of dihomo‐γ‐linolenic acid (DGLA, 20∶3n−6), without a significant elevation in arachidonic acid (AA, 20∶4n−6) and decreases in n−3 polyunsaturated fatty acids. In the case of PC, a net rise in DGLA of 1.8 mol% was observed by day 22 (from 2.1 to 3.9 mol%). The DGLA/AA ratios at day 43 exhibited considerable variability across phospholipids with PC>PS>PE=PI; the PC, PE, PS, and PI accounted for 67.6, 16.7, 12.9, and 2.6%, respectively, of the total DGLA in platelet phospholipids. Interestingly, despite the lack of DGLA in SPH, this phospholipid exhibited a marked enrichment in nervonic acid (NA, 24∶1n−9) from 16.2 to 24.7 mol% upon borage oil consumption. The observed alterations may represent biochemical strategies for adaptation to dietary fatty acid modifications and the regulation of platelet membrane functioning.
The effect of short‐term lipid infusion on liver function and biliary secretion in rats
Authors: Rubin M. , Halpern Z. , Livoff A. , Wennberg A. , Tietz A. , Antebi E. , Lichtenberg D. 
Published: November 2006

AbstractThis study was undertaken to determine the effect of various lipid emulsions on the hepato‐biliary system in rats. Rats were randomly divided into six groups and infused continuously for 48 hr with either long‐chain triglycerides (LCT), medium‐chain triglycerides (MCT) or a mixture of MCT and LCT. One group infused with physiological saline solution served as controls. Throughout this period the rats received a fat free dietad libitum. During the last hour of lipid infusion bile was collected for determination of bile flow and composition. Subsequently, the rats were sacrificed and the morphology and lipid content of the liver determined. Only LCT lipid emulsions induced morphological changes and increased liver cholesterol content. In two rats infused with radiolabeled LCT, no labeled cholesterol was found in the liver, indicating that the excess hepatic cholesterol level may originate from enhanced cholesterol mobilization to the liver. Biliary cholesterol and phospholipid concentrations in LCT‐treated rats were also elevated, as was the lithogenic index, whereas the other emulsions had no such effects. None of the emulsions affected the plasma liver function tests or bile flow. We therefore conclude that the lithogenicity of the bile in rats is directly related to the lipid components of the total parenteral nutrition and the type of triglyceride infused.
Derivatives of Di‐O‐octanoylglycerol and mono‐O‐octylglycerol as modulators of protein kinase C and diacylglycerol kinase activities
Authors: Goddat Jacqueline , Coste Hervé , Vilgrain Isabelle , Chambaz Edmond , Driguez Hugues 
Published: November 2006

AbstractTwelve analogs of 1,2‐di‐O‐octanoylglycerol modified at C‐3 and three quaternaryN‐alkyl‐ammonium derivatives of glycerol were synthesized. The compounds were testedin vitro as potential modulators of the calcium activated, phospholipid dependent protein kinase C (PKC) and diacylglycerol (DAG) kinase activities in order to understand the molecular interactions of these enzymes with their natural activators, inhibitors, or substrates. PKC activity was assayed by measuring histone H1 phosphorylation, and the compounds synthesized were tested either in the presence (inhibitors) or in the absence (activators) of 1,2‐di‐O‐octanoyglycerol analogs with the phosphatidylserine/Ca2+ mixture. DAG kinase activity was measured by the incorporation of phosphate into 1,2‐di‐O‐oleoyl‐sn‐glycerol in the presence of the various analogs synthesized. In regard to PKC activity, the assays revealed that 1,2‐di‐O‐octanoylglycerol analogs are inactive when modified at C‐3 with groups which do not permit hydrogen bonding. Under our conditions, di‐O‐octanoylthioglycerol, which has been reported as inactive, was able to activate PKC in the presence of phosphatidylserine. It has been shown to give a synergistic activation with diacylglycerol and had no affinity for the phorbol ester receptor binding site, suggesting thatO‐octanoylthioglycerol interacts with the enzyme at a different site from the phorbol ester receptor binding site. PKC and DAG kinase activities are inhibited byN‐alkyl‐ammonium compounds (IC50 24 μM) only when either two 8‐carbon alkyl or acyl chains are present at the 1‐ and 2‐positions of the glycerol backbone. The fact that these compounds have a strong effect on the binding of [3H]phorbol 12,13‐dibutyrate to protein kinase C, and also inhibit DAG kinase, may suggest binding to the DAG site of the regulatory domain of PKC.
Effect of prenatal and postnatal exposure to ethanol on rat central nervous system gangliosides and glycosidases
Authors: Prasad V. V. T. S. 
Published: November 2006

AbstractWe investigated the effect of maternal alcohol consumption on cell number, gangliosides and ganglioside catabolizing enzymes in the central nervous system (CNS) of the offspring. Virgin female rats of the Charles Foster strain were given 15% (v/v) ethanol in drinking water one month prior to conception and during gestation and lactation. At 21 days postnatal age, the offspring were sacrificed and the brains were separated into cerebrum, cerebellum and brain stem to investigate possible regional variations. Compared to controls, wet weight of cerebrum, cerebellum and brain stem, and of spinal cord was decreased in the pups exposed to alcohol. DNA and protein contents were also found to be lowered in all the CNS regions of the pups exposed to alcohol. Conversely, maternal alcohol consumption was found to increase the concentration and the content of total gangliosideN‐acetylneuraminic (NANA) in CNS of the pups. In addition, alcohol treatment was found to induce alterations in the proportions of individual ganglioside fractions. Interestingly, these alterations are somewhat different than those observed in the neonatal brain and spinal cord of the pups subjected to prenatal alcohol exposure. The alterations in the proportions of ganglioside fractions were shown to be region‐specific. Maternal alcohol consumption resulted in decreased activities of sialidase, β‐galactosidase, β‐glucosidase and β‐hexosaminidase. The results suggest that the alcohol‐associated increases in ganglioside concentration may be at least partly due to the decreased activities of ganglioside catabolizing enzymes.
Fluorospectroscopic analysis of the fluorescent substances in peroxidized microsomes of rat liver
Authors: Minamide Yoshiyuki , Horie Toshiharu , Awazu Shoji 
Published: November 2006

AbstractThe fluorescent substances formed in rat liver microsomes in the course of lipid peroxidation were investigated by fluorescence techniques. The fluorescence emitted from peroxidizing microsomes continuously increased as lipid peroxidation progressed, while the steady‐state fluorescence anisotropy increased and then reached a plateau. A similar increase was observed in the steady‐state fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene in peroxidizing microsomes. The fluorescence from peroxidized microsomes consisted of at least three species having short, middle or long fluorescence lifetimes. The lifetimes and relative amplitudes of fluorescence were unaffected by the extent of lipid peroxidation. Both fluorescence of the chromolipids extracted and the proteins isolated from peroxidized microsomes had the same characteristics in fluorescence lifetimes as the fluorescence from whole peroxidized microsomes. Thus, these lipids and proteins appear to be the major biological substances responsible for the fluorescence emanating from whole peroxidized microsomes. Furthermore, fluorescent substances formed in microsomes seem to increase in quantity rather than change in quality as lipid peroxidation progresses.
A study of the composition of fish liver and body oil triglycerides
Authors: McGill Alister S. , Moffat Colin F. 
Published: November 2006

AbstractSilver‐ion high‐performance liquid chromatography (Ag+‐HPLC) was used to study the range and variations in molecular species of triglycerides from industrial, retail and laboratory extracted fish oils. These were contrasted with a typical plant oil. Selected fish oils were fractionated and the fatty acid distribution of the fractions determined by gas‐liquid chromatography. Fish oils gave a characteristic Ag+‐HPLC profile, typified by sharp, intense peaks at the start of the chromatogram and broad, multiple nongaussian peaks for the late eluting components. Triglycerides ranging from those that were wholly saturated to those containing 16 double bonds were isolated. Cod (Gadus spp.), saithe (Pollachius virens) and monkfish (Squatina squatina) liver oils gave similar triglyceride profiles. Mackerel (Scomber scombrus), capelin (Mallotus villosus) and herring (Clupea harengus) body oils gave characteristic triglyceride profiles which were associated with high concentrations of 20∶1 and 22∶1 fatty acids. Only small amounts of these particular triglycerides were observed for menhaden (Brevoortia spp.), South African anchovy (Engraulis capensis) and Indian sardine (Sardinella longiceps) oils, all of which contained minor amounts of these acids. The latter oils contained highly unsaturated triglycerides, whereas only traces of these were noted for the former. Chromatography with Ag+‐HPLC can be used for the rapid screening of fish oils and for selecting those oils rich in polyunsaturated acids that may be suitable for enrichment. Cottonseed oil gave well‐defined and discrete peaks. Similar peaks were observed in the chromatogram of Omega‐combination, a mixture of primrose and fish oils. Thus, fish, plant and a mixture of these oils can be readily distinguished.
Terpenes in sponge cell membranes: Cell separation and membrane fractionation studies with the tropical marine spongeAmphimedon sp.
Authors: Garson Mary J. , Thompson Janice E. , Larsen Rundi M. , Battershill Christopher N. , Murphy Peter T. , Bergquist Patricia R. 
Published: November 2006

AbstractThe differing sponge and symbiotic microbial cell types in the tropical marine spongeAmphimedon sp. were fractionated according to density, investigated by electron microscopy, and analyzed by high‐performance liquid chromatography and nuclear magnetic resonance for the presence of the terpene metabolite diisocyanoadociane (1) and Δ5,7‐sterols (2–7). A sample of whole sponge was dissected into superficial ectosome and deeper choanosome. The superficial tissue was found to be enriched in sterol relative to choanosome; however, extracts from both tissues contained terpene. Dissociation of whole sponge followed by Ficoll density gradient fractionation showed that there are two chemically distinct types of sponge cells inAmphimedon sp.—small non‐nucleolated cells of low density contain terpene 1 together with sterols, while larger nucleolated cells contain significant levels of terpene, but only traces of sterol. Membrane fractionation studies were undertaken to establish whether the terpene components were located specifically in the cell membranes of these two cell types. A membrane vesicle pellet spun down at 100,000×g from small sponge cells contained sterols, but only traces of terpene, whereas the membrane vesicle preparation from heavier cells contained both terpenes and sterols. Subsequently, the presence of terpenes together with sterols was demonstrated in a membrane vesicle preparation of purity >90% prepared from bacteria‐free sponge cells. These results provide the first experimental evidence that terpenes are associated with sponge cell membranes, where they may function as structural components.
High‐performance liquid chromatographic separation of enantiomeric benzyl glycerides
Authors: Foglia Thomas A. , Maeda Kazuhito 
Published: November 2006

AbstractThe enantiomeric resolution of a series of 1,2‐diacyl‐ and 1,2‐mixed acid‐diacyl‐3‐benzyl‐rac‐glycerols was investigated by high‐performance liquid chromatography (HPLC). Of the racemic benzylglycerols studied, the 1‐O‐benzyl‐2,3‐O‐iso‐propylidene‐rac‐glycerol 1‐acyl‐3‐benzyl‐rac‐glycerol and 2‐acyl‐3‐benzyl‐rac‐glycerol structures could be resolved into their enantiomers. The latter were resolved on a silica (10 μm) column coated with cellulose tribenzoate by isocratic elution with hexane/isopropanol mixtures as mobile phase. The effects of para substitution of the benzyl moiety on the resolution of the acylbenzylglycerols by this HPLC method were evaluated.
Geotrichum candidum NRRL Y‐553 lipase: Purification, characterization and fatty acid specificity
Authors: Baillargeon Mary Welch , McCarthy Stephen G. 
Published: November 2006

AbstractLipases fromGeotrichum candidum NRRL Y‐553 are of interest because of their unique specificity forcis‐9‐unsaturated fatty acids relative to both stearic and palmitic acids. The lipases were partially purified by chromatography on Octyl Sepharose, AG MP‐1 macroporous anion exchanger, and chromatofocusing resin. The preparation was found to contain multiple, glycosylated lipases varying slightly in pI (pI 4.88, 4.78, 4.65, 4.57 and 4.52) as judged by both activity and silver staining. The molecular mass determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis was 64 kilodaltons for the main species, with minor species of 60 and 57 kilodaltons present as well. The specificity of the crude lipases for hydrolysis of 4‐methylumbelliferyl esters of oleicvs. palmitic acid was 20‐to‐1. The specificity of the purified, partially separated lipases was similar to that of the crude preparation. Thus the lipases could be used even in crude form for the hydrolysis and restructuring of triacylglycerols on a large scale.
A novel method for the introduction of a methyl group into the furan ring of a 2,5‐disubstituted C18 furanoid fatty estervia a malonic acid function
Authors: Lie Ken Jie Marcel S. F. , Wong Ka‐Po 
Published: November 2006

AbstractFuran ring opening with benzohydroxamic acid of methyl 9,12‐epoxy‐9,11‐octadecadienoate gave a mixture of positional isomers of conjugated methyl 3‐phenyl‐1,4,2‐dioxazolyl C18‐enone esters 6a,6b. Michael addition of diethyl malonate anion to the conjugated enone system of 6a,6b furnished the corresponding malonyl intermediates 7a,7b, which upon removal of the dioxazole ring by hydrolysis gave methyl 10‐ and 11‐dicarbethoxymethyl‐9,12‐dioxooctadecanoate 8a,8b. Cyclization of the latter gave the trisubstituted C18 furanoid fatty esters 9a,9b, containing the malonate ester function at the 3‐/4‐position of the furan ring. Base hydrolysis of compounds 9a,9b gave the corresponding tricarboxylic acid derivatives 10a,10b, which were esterified to the trimethyl esters 11a,11b in BF3/MeOH. When a mixture of 9a,9b was refluxed with Na2CO3/MeOH, hydrolysis of the malonate ester function was followed by decarboxylation to yield a‐CH2COOH substituent at the 3‐/4‐position of the furan ring (12a, 12b). Esterification of the latter with BF3/MeOH gave the corresponding methyl diester derivatives 13a,13b. When a mixture of tricarboxylic acids 10a,10b was heated at 160–180°C for 6 hr, exhaustive decarboxylation of malonic acid function furnished a methyl group at the 3‐/4‐position of the furan nucleus. Esterification of the decarboxylated product gave a mixture of trisubstituted furanoid compounds 14a,14b (overall yield 28%). The procedure constitutes a novel method for the introduction of a methyl groupvia a malonic acid group to the 3‐/4‐position of the furan ring of a 2,5‐disubstituted C18 furanoid fatty ester.
Preparation and some spectroscopic properties ofN‐heterocyclic derivatives of a novel 1‐pyrroline C18 fatty ester
Authors: Lie Ken Jie Marcel S. F. , Syed‐Rahmatullah M. S. K. 
Published: November 2006

AbstractA C18 1‐pyrroline fatty ester, methyl 8‐(5‐hexyl‐2‐pyrrolin‐1‐yl)octanoate (1), was prepared from methyliso‐ricinoleate. The C=N bond of the pyrroline ring was oxidized bym‐chloroperoxy‐benzoic acid to yield a mixture of oxaziridine isomers 2a,2b, which decomposed during gas chromatographic analysis to a 2,5‐disubstituted pyrrole derivative, methyl 8‐(5‐hexyl‐1H‐pyrrole‐2‐)octanoate (3). Compound 3 was also obtained by reaction of 2a,2b with dilute HCl in methanol. Reaction of compound 1 with iodo‐methane formed anN‐methyl iminium iodide intermediate 4, which on reduction with sodium borohydride furnished a mixture ofcis/trans‐N‐methyl‐2,5‐disubstituted pyrrolidine derivatives, methyl 8‐(cis/trans‐5‐hexyl‐N‐methyl‐pyrrolidine‐2‐)octanoates 5a,5b. Reduction of compound 1 with NaBH4 gave a mixture ofcis/trans‐isomers of 2,5‐disubstituted pyrrolidine derivatives, methyl 8‐(5‐hexyl‐pyrrolidine‐2‐)octanoates 6a,6b. Acetylation of compounds 6a,6b with acetic anhydride furnished the correspondingN‐acetyl pyrrolidines 7a,7b. When compound 1 was treated with perchloric acid, the corresponding iminium perchlorate derivative, methyl 8‐(5‐hexyl‐1‐pyrrolinium perchlorate‐2‐)octanoate 8 was obtained. The structures of the various derivatives were characterized by a combination of chromatographic, mass spectral and spectroscopic techniques.
Inhibition of ferrous‐induced lipid peroxidation by pyrimido‐pyrimidine derivatives in human liver membranes
Authors: de la Cruz J. P. , Carrasco T. , Ortega G. , de la Cuesta F. Sanchez 
Published: November 2006

AbstractThe effects of pyrimido‐pyrimidine derivatives (dipyridamole, RA‐642, and RA‐233) on lipid peroxidation, using d‐α‐tocopherol as standard, were studied in enriched membrane fractions from human and rat hepatocytes. Equimolar concentrations of ferrous sulfate and ascorbic acid were used to induce lipid peroxidation. The amount of peroxidized lipids observed in membrane fractions from human liver was smaller than in those from rat liver. In both species, however, pyrimido‐pyrimidine derivatives, except for RA‐233 in rat liver, inhibited lipid peroxidation dose‐dependently in the following sequence: RA‐642 > dipyridamole > d‐α‐tocopherol RA‐233.
α‐tocopherol oxidation mediated by superoxide anion (O2−) I. Reactions in aprotic and protic conditions
Authors: Csallany A. Saari , Ha Yeong L. 
Published: November 2006

AbstractThe reaction of α‐tocopherol (α‐T) with superoxide anion (O2−) in both dry acetonitrile and in aqueous acetonitrile solution is described. The O2− was generated by the electrochemical reduction of molecular oxygen in acetonitrile, using tetrabutylammonium bromide as an electrolyte. α‐T was reacted with O2− either in dry acetonitrile or in a 10% aqueous acetonitrile solution. In dry acetonitrile, α‐T was oxidized to a very unstable primary intermediate, which was further oxidized to a secondary, more stable intermediate. The formation of the secondary intermediate depended upon the presence of molecular oxygen. This intermediate readily converted into two compounds in equimolar amounts (designated A and B). The primary, very unstable intermediate was readily reduced again to α‐T by treatment with LiAlH4 or ascorbic acid. However, the secondary intermediate or the stable oxidation products could not be reduced to α‐T. In the 10% aqueous acetonitrile, α‐T was oxidized to α‐tocopheryl quinone, α‐tocopherol dimer and α‐tocopherol dihydroxy dimer, and an unknown compound. In the aqueous medium, no intermediates were formed by the action of O2−. The results of this study indicate that the reaction of α‐T with O2− under aprotic conditions is different from that observed under protic conditions.
α‐tocopherol oxidation mediated by superoxide anion (O2−). II. Identification of the stable α‐tocopherol oxidation products
Authors: Ha Yeong L. , Csallany A. Saari 
Published: November 2006

AbstractThe present paper describes the identification of two stable end products of α‐tocopherol oxidation that were previously detected among the products of the reaction of α‐tocopherol with superoxide anion (O2−) under aprotic conditions. One compound, previously designated compound A, was identified astrans‐7‐hydroxy‐trans‐8,8a‐epoxy‐α‐tocopherone, and the other, designated compound B, was identified ascis‐7‐hydroxy‐cis‐8,8a‐epoxy‐α‐tocopherone. It was also observed that under protic conditions (10% water in acetonitrile) the reaction of α‐tocopherol with O2− did not produce compounds A and B, but rather α‐tocopheryl quinone, α‐tocopherol dimer, α‐tocopherol dihydroxy dimer, and the previously designated compound C. Compound C was identified in the present study as α‐tocopheryl‐quinone‐2,3‐epoxide.
The inhibitory effect of water on the Co2+ and Cu2+ catalyzed decomposition of methyl linoleate hydroperoxides
Authors: Chen H. , Lee D. J. , Schanus E. G. 
Published: November 2006

AbstractThe inhibitory effect of water on the decomposition of methyl linoleate hydroperoxides (MLHP) catalyzed by Co2+ and Cu2+ was studied in a model system using proton nuclear magnetic resonance (NMR) spectroscopy. MLHP were prepared by photoxidation and purified by chromatographic methods. Proton NMR spectroscopy was used to measure reaction rates by monitoring changes in the intensity of the OOH signal. The rate constant of the reaction was obtained by plotting the natural logarithm of MLHP concentrationvs time. In the first part of the study, no transition metals were added to the model system, so that the effect of water could be attributed to the interaction between water and MLHP only. The rate constant of the reaction (K) was found inversely proportional to the concentration of water. There was a downfield chemical shift of both hydroperoxide and water peaks in the NMR spectra when water was added. As temperature increased to 40°C, the difference in K between the systems with 0% and 2% water disappeared. It is proposed that the hydroperoxides were solvated with water which retarded their decomposition. When Co2+ was added to the model system, K decreased as the concentration of water increased from 0% to 1.5%. As temperature increased from 18°C to 40°C, differences between the K for 0% and 2% water disappeared. A similar phenomenon was observed in reactions catalyzed with Cu2+. These findings would support a mechanism in which the protective effect of water involves both the solvation of OOH and hydration of the metal catalyst.