bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of selective ion monitoring to the analysis of molecular species of vegetable oil triacylglycerols separated by open‐tubular column GLC on a methylphenylsilicone phase at high temperature
Authors: Ohshima Toshiaki , Yoon Hyung‐Sik , Koizumi Chiaki 
Published: December 2006

AbstractAnalyses of the molecular species of authentic triacylglycerols and of soybean triacylglycerols, which were separated on a fused silica open‐tubular column coated with a methylphenylsilicone gum stationary phase, were carried out by selective ion monitoring mass spectrometry. It was determined that peak assignments could be made by selecting certain characteristic ions with the same retention time on the SIM profile, that is, three ions of the type RCO+ corresponding to the fatty acyl residues (R1CO+, R2CO+ and R3CO+) and the corresponding three M‐acyl ions ([M‐OCOR1]+, [M‐OCOR2]+ and [M‐OCOR3]+ instead of the molecular ion. The yield of [RCO‐1]+ and [RCO‐2]+ and relating these to the unsaturated fatty acyl residues is inconvenient for an exact peak assignment. The SIM method was further applied to the peak assignment of the triacylglycerols from palm, cottonseed and safflower oils and certain new fatty acid combinations are proposed.
Sialylation of lacto‐N‐neotetraosyl ceramide by a solubilized sialyltransferase(s) from chicken skeletal muscle: Effect of phosphatidylcholine and sphingomyelin
Authors: Dasgupta Somsankar , Chien Jaw‐Long , Hogan Edward L. 
Published: December 2006

AbstractThe sialytransferase(s) that transfers sialic acid to lacto‐N‐neotetraosylceramide and other glycosphingolipids with a galactose nonreducing terminus has been successfully solubilized from embryonic chicken skeletal muscle. The enzyme can be stored in 50 mM HEPES (pH 6.8), 1% Triton CF‐54, and 20% glycerol at −70°C for as long as six months. Addition of phosphatidylcholine or sphingomyelin (0.167%) readily reactivates the stored inactive enzymes and such activity persists for about two weeks at 0°–4°C with the peak activity occurring at 1 to 2 days. Sphingomyelin from chicken muscle, which contains mainly C16∶0 and C18∶0, is 2.1‐fold more effective than bovine brain sphingomyelin at the same concentration (0.4%).
Lack of effects oftrans fatty acids on eicosanoid biosynthesis with adequate intakes of linoleic acid
Authors: Zevenbergen J. L. , Haddeman E. 
Published: December 2006

AbstractThe minimum requirement of linoleic acid to prevent effects of dietary C18trans fatty acids on eicosanoid biosynthesis in rats was assessed. In a first experiment, six groups of animals were fed diets with a high content oftrans fatty acids [20% of energy (en%)], and increasing amounts of linoleic acid (0.4 to 7.1 en%). In a second experiment, four groups of rats were fed diets designed to comparetrans fatty acids with saturated andcis‐monounsaturated fatty acids of the same chain length at the 2 en% linoleic acid level. After 9–14 weeks the biosynthesis of prostacyclin by pieces of aorta and the biosynthesis of hydroxy‐heptadecatrienoic acid and 12‐hydroxy‐eicosatetraenoic acid by platelets were measured. The fatty acid compositions of aorta phospholipid and platelet lipid were also determined. Both the prostacyclin‐production by aorta pieces and the production of hydroxy‐heptadecatrienoic acid and 12‐hydroxy‐eicosatetraenoic acid by platelets appeared to be a linear function of the arachidonic acid level in aorta phospholipid and platelet lipid, irrespective of thetrans fatty acid content in the diet. This indicates thattrans fatty acids do not directly influence enzymes involved in eicosanoid biosynthesis. In a direct comparison withcis‐monounsaturated or saturated fatty acids with 2 en% linoleic acid in the diet, only a moderate reduction in arachidonic acid level in aorta phospholipids in the group fedtrans fatty acids was observed. The geometry of the double bond did not influence the arachidonic acid level in platelet lipid, although the diet rich in saturated fatty acids increased arachidonic acid levels significantly compared with all other diets. Neither prostacyclin‐production nor hydroxy‐heptadecatrienoic acid or 12‐hydroxy‐eicosatetraenoic acid‐production were significantly affected bytrans fatty acids when 2 en% linoleic acid was present in the diet. Our study indicates that in rats 2 en% linoleic acid is sufficient to prevent effects of dietarytrans fatty acids on eicosanoid synthesis.
On the specificity of a phospholipase A2 purified from the 106,000×g pellet of bovine brain
Authors: Gray N. C. C. , Strickland K. P. 
Published: December 2006

AbstractAssessment has been made of the specificity of a purified phospholipase A2 from the 106,000×g pellet (microsomal fraction) of bovine grey matter which shows strong activity toward phosphatidylinositol (PI). In the first series of experiments involving the utilization as substrates of PI with different14C‐ or3H‐labeled fatty acids in the 2‐position, the purified phospholipase A2 most readily removed 16∶0 palmitic acid, followed by 18∶0 stearic acid, 18∶1 oleic acid and 20∶4 arachidonic acid. In the second series of experiments, the purified phospholipase A2 showed preferential action toward PI (100%) compared to phosphatidylcholine (PC, 62.5%), phosphatidic acid (PA, 32.6%), phosphatidylethanolamine (PE, 25.1%) and phosphatidylserine (PS, 21.5%), where each phosphoglyceride was labeled in the 2‐position with [1‐14C] oleic acid. In the third series of experiments, fatty acids were shown to cause inhibition of action of the purified phospholipase A2 on 1‐acyl, 2‐[1‐14C] oleoyl PI in the order 20∶4>18∶1>18∶0>16∶0 which is the reverse order to that just noted. In the final series of experiments, the addition of the phosphoglycerides PC, PE, PS and PA in amounts of 5 or 10 μM caused either no inhibition (PE, 2%), slight inhibition (PC, 15%) or reasonably significant inhibition (PA, 20% and PS, 40%) of action of the purified phospholipase A2 on 1‐acyl, 2‐[1‐14C]‐oleoyl PI. The pattern of specificity observed for the purified phospholipase A2 combined with its microsomal location are the expected properties of a phospholipase A2 that might function in a deacylation‐reacylation cycle for modifying the fatty acid distribution in PI.
Gas chromatographic assay of the diastereomeric composition ofall‐rac‐α‐tocopheryl acetate
Authors: Scott Clifford G. , Cohen Noal , Riggio Patrick P. , Weber Giuseppe 
Published: December 2006

AbstractIt has been established by an evaluation of 6 production samples ofall‐rac‐α‐tocopheryl acetate that all 4 racemates (RRS/SSR, RRR/SSS, RSR/SRS and RSS/SRR) are consistently present in equimolar amounts (SD<0.3, RSD<1.2%). An analysis of variance indicated variance due to signal noise to be consistent within a sample run but to vary from day to day. Variance due to area measurement was greater for the first and last eluted racemates than for the second and third. Peak width and asymmetry were found to be extremely sensitive to sample loading and, even within acceptable limits for good quantitation, the distortion was sufficient to give the elution profile the appearance of a sample composed of 4 components in unequal proportions increasing according to the order of elution.
A convenient method for the preparation of asialo‐GM1
Authors: Kasai Noriyuki , Sillerud Laurel O. , Yu Robert K. 
Published: December 2006

AbstractA convenient and efficient procedure has been devised for the large‐scale preparation of asialo‐GM1 from bovine brain gangliosides. The procedure relies on the complete desialylation of brain ganglio‐sides, consisting primarily of GM1, GD1a, GD1b and GT1b, by mild formic acid hydrolysis (0.1 N, 100 C; 2 hr). Following the hydrolysis step, asialo‐GM1 can be isolated and purified by Folch partitioning and Iatrobeads column chromatography, with an overall yield of more than 50%.
Oral contraceptive and platelet lipid biosynthesis in female rats: Dose‐response relationship
Authors: Ciavatti M. , Davenas E. , Michel G. , Renaud S. 
Published: December 2006

AbstractFemale rats were treated with different doses of an oral contraceptive (ethinyl estradiol + lynestrenol) and lipid biosynthesis was studied in blood platelets by acetate incorporation into different fractions separated by thin layer chromatography. A marked increase in lipid biosynthesis was observed, especially in the sterol fractions (cholesterol and lanosterol‐dihydrolanosterol). It was dose‐dependent, observed after a lag‐phase, maximal in 3 days and normalized in 8 days. Thus, the oral contraceptive studied here appears to modify platelet lipid biosynthesis for the entire life of the platelets.
Comparison of bile acid synthesis determined by isotope dilution versus fecal acidic sterol output in human subjects
Authors: Duane William C. , Holloway David E. , Hutton Scot W. , Corcoran Patricia J. , Haas Nancy A. 
Published: December 2006

AbstractFecal acidic sterol output has been found to be much lower than bile acid synthesis determined by isotope dilution (J. Lipid Res. 17: 77, 1976). Because of this confusing discrepancy, we compared these 2 measurements done simultaneously on 13 occasions in 5 normal volunteers. In contrast to previous findings, bile acid synthesis by the Lindstedt isotope dilution method averaged 16.3% lower than synthesis simultaneously determined by fecal acidic sterol output (95% confidence limit for the difference −22.2 to −10.4%). When one‐sample determinations of bile acid pools were substituted for Lindstedt pools, bile acid synthesis by isotope dilution averaged 5.6% higher than synthesis by fecal acidic sterol output (95% confidence limits −4.9 to 16.1%). These data indicate that the 2 methods yield values in reasonably close agreement with one another. If anything, fecal acidic sterol outputs are slightly higher than synthesis by isotope dilution.
Metabolism of malonaldehyde in vivo and in vitro
Authors: Siu G. M. , Draper H. H. 
Published: December 2006

AbstractThe metabolism of malonaldehyde (MA) was investigated in vivo using male Wistar rats and in vitro using rat liver mitochondria. Twelve hr after intubation with [1,3‐14C] MA, 60–70%, 5–15% and 9–17% of administered radioactivity was recovered in expired CO2, feces and urine, respectively. In rats intubated with [1,2‐14C] acetate, the corresponding values were 68–82%, 1–2% and 2–3%.14CO2 evolution was initially slower after14C‐MA administration than after14C‐acetate administration and more radioactivity was excreted in the feces and urine. In vitro experiments using [1,3‐14C] MA showed that MA is metabolized primarily in the mitochondria via reactions involving O2 utilization and14CO2 production. The apparent Km and Vmax were 0.5 mM and 9.3 nmol/min/mg protein for O2 uptake, respectively, and 2.0 mM and 2.4 nmol/min/mg protein for14CO2 production. Addition of malonic acid to mitochondrial incubates at concentrations inhibitory to succinate dehydrogenase did not affect MA‐induced O2 uptake but enhanced14CO2 production from14C‐MA.14C‐Acetate appeared to be the major accumulating metabolite in rat liver mitochondrial preparations following a 120‐min incubation with14C‐MA. A probable biochemical route for MA metabolism involves oxidation of MA by mitochondrial aldehyde dehydrogenase followed by decarboxylation to produce CO2 and acetate.
Reduction of myocardial necrosis in male albino rats by manipulation of dietary fatty acid levels
Authors: Kramer J. K. G. , Farnworth E. R. , Thompson B. K. , Corner A. H. , Trenholm H. L. 
Published: December 2006

AbstractA comprehensive statistical analysis had shown a significant correlation between the incidence of myocardial lesions in male albino rats and the concentration of certain dietary fatty acids. To test this result under controlled conditions, male rats were fed for 16 weeks diets containing 20% by weight soybean oil or a low erucic acid rapeseed (LEAR) oil. Both dietary oils contained substantial amounts of linolenic acid, and both groups developed a high incidence of myocardial necrosis. The addition of dietary saturated fatty acids to the oil in the form of cocoa butter significantly lowered the incidence of heart lesions in both groups. The addition of cocoa butter resulted in increased absorption of saturates and increased growth. Replacement of the cocoa butter by at least an equal amount of synthetic triolein resulted in no significant changes in the cardiopathogenic response compared to the original oils, thus ensuring that the reduction in heart lesions associated with the addition of cocoa butter was not due to dilution of cardiopathogenic compounds in the original vegetable oils. These results support the hypothesis that myocardial lesions in male rats are related to the balance of dietary fatty acids and not to cardiotoxic contaminants in the oils. Changes in the dietary fatty acids did not appear to influence the proportion of the cardiac phospholipids, but their fatty acid composition was markedly influenced. Dietary linolenic acid affected the C22 polyunsaturated fatty acids (PUFA) and dietary saturates increased the level of saturates in cardiac phospholipids. The level of arachidonic acid and total C22 PUFA did not appear to be affected by diet.
Hepta‐and nonadecene from marine fish
Authors: Hoshita Nobuhiko , Kodama Youtaro 
Published: December 2006

AbstractTwo monoalkenes were detected in gizzard shad (Clupanodon punctatus) and sardine (Sardinops melanosticta) by gas chromatography and were identified by combined gas chromatography‐mass spectrometry of their cyclic boronate and dioxolane derivatives ascis‐6‐n‐heptadecene andcis‐8‐n‐nonadecene.
Effect of diethyl maleate and glutathione on linoleate peroxidation
Authors: Fernandez Nancy , Valenzuela Alfonso , Fernandez Virginia , Videla Luis A. 
Published: December 2006

AbstractThe antioxidant effect of diethyl maleate and reduced glutathione was studied in an in vitro peroxidizing system. Linoleate peroxidation, measured as conjugated diene formation, was not altered by diethyl maleate (2 or 4 mM), whereas the addition of reduced glutathione (1, 2 or 4 mM) elicited a marked and progressive reduction. This effect of glutathione is not modified by diethyl maleate. The inhibition of linoleate peroxidation by glutathione was found concomitantly with a decrease in the concentration of its reduced form and a corresponding increase in glutathione disulfide levels, so that the total equivalents of reduced glutathione in the system remained constant. It is concluded that diethyl maleate does not have antioxidant properties in a peroxidizing system, as found for reduced glutathione.
Effects of phosphatidylcholines on de novo synthesis and excretion of sterol by L‐929 fibroblasts
Authors: Thomaidis Georgios , Holmlund Chester E. 
Published: December 2006

AbstractThe effects on [14C] sterol synthesis and excretion by exposure of L‐929 cells to several phosphatidylcholines (PC) has been examined. No significant effects were noted on either parameter during a 6‐hr period if exposure of cells to the phospholipid preceded the addition of [1‐14C] acetate by just 30 min. However, if cultures were grown in media containing delipidized serum and 2×10−5 M PC through 2 or more subculturings prior to adding [1‐14C] acetate, the amount of [14C] sterol increased in both cells and medium by 70–200% when saturated or monounsaturated PC were used. Dilinoleylphosphatidylcholine (18∶2 PC) at the same concentration did not stimulate synthesis or excretion of newly synthesized sterol. Total cellular sterol was determined by gas chromatography, and was only marginally affected by long‐term exposure to dipalmitylphosphatidylcholine (16∶0 PC), whereas the total sterol of the medium increased by 4‐fold over a 19‐hr period. Cultures which had been exposed to 16∶0 PC through 3 subculturings continued to display enhanced de novo sterol synthesis, but not excretion, for up to 5 hr after replacement with fresh medium lacking 16∶0 PC. The disparity in response to 2×10−5 M levels of 16∶0 PC and 18∶2 PC may relate to differences in metabolism of cellular fatty acids, whereas relatively small changes in the cellular fatty acid composition were noted with 16∶0 PC‐treated cells. The results indicate that extracellular PC can promote sterol synthesis and excretion by L‐929 cells, and that the magnitude of this response is influenced by the time of exposure to the phospholipid and by its fatty acid composition.
Use of radiolabeled hexadecyl cholesteryl ether as a liposome marker
Authors: Pool G. L. , French M. E. , Edwards R. A. , Huang L. , Lumb R. H. 
Published: December 2006

AbstractRadiolabeled hexadecyl cholesteryl ether can serve as an effective marker for liposomes in a variety of studies. This paper demonstrates the use of a cholesteryl ether marker in the assay of phospholipid transfer protein activity and in assessing phospholipid vesicle‐cell interactions. The cholesteryl ether has the advantages of ease of synthesis, metabolic inertness, lipid solubility and nonexchangeability.
An improved procedure for the synthesis of choline phospholipids via 2‐bromoethyl dichlorophosphate
Authors: Hansen William J. , Murari Ramaswamy , Wedmid Yuri , Baumann Wolfgang J. 
Published: December 2006

AbstractCholine phospholipids can be conveniently synthesized by reaction of a lipophilic alcohol, such as diacylglycerol, with 2‐bromoethyl dichlorophosphate followed by nucleophilic displacement of the bromine with trimethylamine. We found that the low yields often encountered in the initial phosphorylation step are particularly due to exchange of both chlorines for alkoxy functions (triester formation) and to chlorination of the alcohol by 2‐bromoethyl dichlorophosphate. However, these drawbacks can be overcome by proper choice of the reaction medium and by optimizing other reaction conditions. The procedure described is efficient and most versatile, and it lends itself to the preparation of a wide range of choline phospholipids containing a glycerol, diol, or long‐chain alkyl backbone and bearing various aliphatic functions. Proton and carbon‐13 nuclear magnetic resonance spectroscopy proved useful in establishing the homogeneity and structures of the synthetic intermediates and byproducts and of the choline phospholipids synthesized.
Effect of garlic (Allium sativumlinn) on serum lipoproteins and lipoprotein cholesterol levels in albino rats rendered hypercholesteremic by feeding cholesterol
Authors: Kamanna V. S. , Chandrasekhara N. 
Published: December 2006

AbstractThe hypocholesteremic activity of garlic was tested by incorporating freeze‐dried garlic powder at 0.5, 1.0, 2.0 and 3.0% levels in an atherogenic diet fed to rats. It was observed that 0.5 and 1.0% levels were not effective whereas the other 2 levels were. The group fed 2.0% garlic powder had much lower serum cholesterol level than the one fed 3%. The increased levels of low density lipoproteins (LDL) and LDL‐cholesterol in rats fed the atherogenic diet were partly reversed in rats receiving a supplement of 2% garlic powder. On a cholesterol‐containing diet, high density lipoproteins (HDL) and HDL‐cholesterol levels were decreased. Inclusion of garlic powder in the atherogenic diet enhanced the percentage of HDL whereas no change was observed in HDL cholesterol levels. Commercial garlic pearls (equivalent to 0.15% garlic powder in the diet) produced a significant decrease in serum and liver cholesterol levels in rats fed the atherogenic diet. On the other hand, asafoetida at 1.5% level failed to reduce the serum cholesterol levels in the cholesterol‐fed rats.
A simple method for labeling lipids in the bile lipoprotein
Authors: Nalbone Gilles , Vigne Jean‐Louis , Lafont Huguette , Augeire‐Charbonnier Monique , Chabert Christiane , Lairon Denis , Hauton Jacques C. 
Published: December 2006

AbstractA simple method is proposed for the specific radioactive labeling of phosphatidylcholines and cholesterol in the bile lipoprotein complex. It can be used for human and animal bile samples and results in labeling with the desired specific radioactivity and position. Experiments which determined the intermicellar concentration of lipid constituents suggested that incorporation of radioactive lipids could occur through small dialyzable structures termed mixed premicelles in therm odynamic equilibrium with the bile lipoprotein complex.
Metabolism of fatty acids in rat brain microsomal membranes
Authors: Aeberhard Ernesto E. , Gan‐Elepano Minerva , Mead James F. 
Published: December 2006

AbstractUsing a technique in which substrate fatty acids are incorporated into microsomal membranes followed by comparison of their rates of desaturation with those of exogenous added fatty acids, it has been found that the desaturation rate may be greater for the membrane‐bound substrate than for the added fatty acid. Moreover, the product of the membrane‐bound substrate is incorporated into membrane phospholipid whereas the product of the exogenous substrate is found in di‐ and triacyl glycerols and in free fatty acids, as well. These and other findings point to a normal sequence of reaction of membrane lipids with membrane‐bound substrate involving transfer of fatty acid from phospholipid to the coupled enzyme systems without facile equilibration with the free fatty acid pool.
Lysophosphatidylcholine acyltransferases activity during experimental cholelithiasis
Authors: Allen Rutledge F. , Hickman Donn M. , Dunn Joceyln J. , Frey Charles F. , Matson Robert S. 
Published: December 2006

AbstractThe accumulation of (1‐palmitoyl)lysophosphatidylcholine, lysolecithin, in gallbladder bile was observed during the first week of cholesterol‐induced experimentals cholelithiasis using the prairie dog model for cholesterol gallstone formation. Gallbladder fluid transport function decreased as bile lysolecithin concentration increased. These observations suggest that lysolecithin play an important, early role in the etiology of gallstone disease. Furthermore, the relative activities of hepatic and gallbladder mucosa lysophosphatidylcholine acyltransferase and acylcoenzyme A hydrolases may be responsible for the turnover of gallbladder bile lysolecithin.
Ceramide structure of sphingomyelin from human milk fat globule membrane
Authors: Bouhours Jean‐François , Bouhours Danièle 
Published: December 2006

AbstractSphingomyelin was purified from human milk fat globule membrane and submitted to phospholipase C to yield ceramide. The structure of this ceramide was investigated by gas liquid chromatographic analyses of its components, fatty acids and sphingoid bases. The structure of the native ceramide was confirmed by direct‐inlet mass spectrometry. It was shown to contain a major base C18‐sphingosine associated with a high proportion (60%) of C20, C22, C24 and C24∶1 nonhydroxylated fatty acids. As these very long‐chain fatty acids might be of nutritive importance, the concentration of sphingomyelin in human milk and its distribution in cream and skim milk were established.
Effects of clofibrate and tiadenol on the elimination of lipids and bile acids in rat bile
Authors: Cuchet P. , Morrier C. , Cand F. , Keriel C. 
Published: December 2006

AbstractThe aim of the work presented here was to compare the biliary elimination of cholesterol and the different bile acids of rats that had been made hypolipidemic by short‐term treatments with clofibrate or tiadenol. Both treatments induced a significant decrease in cholesterol output in the bile. The analysis of the different bile acids showed a decrease in dihydroxylated acids elimination (especially CDC acid) without any difference between the 2 sexes. This decrease was associated with an increase in cholic acid excretion. These results are directly correlated with the dose of the administered hypolipidemic drug. The drugs caused a significant increase in the ratio of trihydroxylated acids to dihydroxylated acids. The maximal effect on the concentration of the biliary acids of the bile and on the output was obtained, for both drugs, with a treatment of 200 mg/kg/day. Clofibrate had a greater effect than tiadenol at this dose. Both drugs show a greater effect on lowering serum lipid levels in female animals when compared to males, whereas elimination of bile cholesterol and modifications of bile acids were greater in male animals than female animals.