bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractPreincubation 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

AbstractThe 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

AbstractPossible 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

AbstractThe 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

Abstractcis‐ 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

AbstractThis 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

AbstractThe 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

AbstractBoth 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

AbstractThe 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

AbstractThe 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.
Sphingolipids in immature and mature soybeans
Authors: Ohnishi Masao , Fujino Yasuhiko 
Published: December 2006

AbstractCeramides and cerebrosides were isolated from immature and mature soybeans, and structures of the constituents were investigated. As component fatty acids, normal, 2‐hydroxy and 2,3‐dihydroxy acids were found in ceramides, whereas only normal and 2‐hydroxy acids were identified in cerebrosides. The principal fatty acid component was 2‐hydroxylignoceric acid in ceramides, and 2‐hydroxypalmitic acid in cerebrosides. Sphingoids in ceramides consisted mainly of trihydroxy bases, with 4‐hydroxy‐trans‐8‐sphingenine being predominant. In contrast, cerebrosides contained mainly dihydroxy bases, the principal constituent beingtrans‐4,trans‐8‐sphingadienine. The only sugar in cerebrosides was glucose. The constituents of the two sphingolipids were similar to each other in immature and mature seeds. Possible metabolic relations of plant sphingolipids, based on composition, are discussed.
Glass capillary gas chromatography‐mass spectrometry of wax esters, steryl esters and triacylglycerols
Authors: Wakeham Stuart G. , Frew Nelson M. 
Published: December 2006

AbstractComplex mixtures of wax esters, steryl esters and triacylglycerols isolated from representative biological and geochemical samples have been analyzed using combined high resolution gas chromatography and electron impact and chemical ionization quadrupole mass spectrometry. These low volatility neutral lipids containing up to 65 carbons were chromatographed intact on 15–20 m high‐temperature (upper limit: 370 C) persilylated SE‐52 and SE‐30 glass capillary columns. Discrimination effects due to adsorptive losses and degradation were minimized using a nonvaporizing on‐column injector and a direct all‐glass capillary connection (370 C) to the quadrupole mass spectrometer. Structural information regarding the fatty acid and alcohol moieties was found to be maximal for methane‐CI spectra in the case of wax and steryl esters, whereas EI spectra were most useful in interpreting triacylglycerol structures. Principal features of the EI and CI fragmentation patterns are discussed. The molecular composition of complex mixtures of these lipids is reconstructed for selected samples.
Riboflavin deficiency and β‐oxidation systems in rat liver
Authors: Sakurai Takehiko , Miyazawa Shoko , Furuta Shuichi , Hashimoto Takashi 
Published: December 2006

AbstractWeanling rats were fed a riboflavin‐deficient diet. The mitochondrial fatty acid oxidation in liver was depressed in riboflavin deficiency but restored after supplementation of riboflavin. Among the enzymes involved in this system, only the acyl‐CoA dehydrogenase (EC 1.3.99.2 and 1.3.99.3) activities varied with the change in fatty acid oxidation. An accumulation of the apoforms of acyl‐CoA dehydrogenases was found in riboflavin deficiency. The levels of electron transfer flavoprotein and other enzymes involved in the β‐oxidation system remained unchanged. The peroxisomal fatty acid oxidation and levels of individual enzymes of this system remained constant. No accumulation of the apoform of acyl‐CoA oxidase was observed under simple, riboflavin‐deficient conditions. However, accumulation of a large amount of apo‐acyl‐CoA oxidase was observed when the peroxisomal system was induced by administration of a peroxisome proliferator, di(2‐ethylhexyl)phthalate, under riboflavin‐deficient conditions.
Fecal steroids in diarrhea: IV. Cholera
Authors: Huang Charles T. L. , Levine Myron M. , Daoud Georgette S. , Nalin David R. , Nichols Buford L. 
Published: December 2006

AbstractFecal bile acid and neutral sterol patterns were studied in eight healthy adult volunteers who were challenged withVibrio cholerae classical Ogawa 395 strain in the course of vaccine development studies. Bacterial 7α‐dehydroxylation of cholic and chenodeoxycholic acids was not altered during experimentally induced cholera diarrhea, despite the fact that fecal weight in g/day (wet wt) was increased greatly during diarrhea (1913±390 vs 161±11 in controls, p<0.005). Consistent with the findings on bile acids, no significant changes in the production of coprostanol, epicoprostanol, or coprostanone were observed although the percentage of unmodified cholesterol was increased during the diarrheal episode (20.7±3.3% vs 11.9±2.3, p<0.02). Total concentrations of both bile acids and cholesterol in mg/g of feces (wet wt) were decreased considerably as a result of diarrhea). However, total bile acid and neutral steroid excretions in mg/kg/day in subjects with and without diarrhea do not appear to be different. Intestinal transit times, measured in eight subjects by the use of carmine red dye, were found to be shortened in diarrhea (5.8±1.1 hr vs 23.4±4.1 hr in controls, p<0.001). The results from this study are similar to those observed in experimentally induced travellers' diarrhea associated with toxigenicEscherichia coli, but they are in striking contrast to the changes in gastrointestinal steroid metabolism observed in acute shigello sis, an invasive intestinal infection.
Fatty acid patterns in iron‐deficient maternal and neonatal rats
Authors: Sherman Adria Rothman , Bartholmey Sandra J. , Perkins Edward G. 
Published: December 2006

AbstractTo determine the effects of maternal iron deficiency on lipid composition and fatty acid patterns in offspring, rats were fed ad libitum diets containing 5 ppm iron (deficient) (n=8) or 320 ppm iron (control) (n=7) and deionized water from day‐1 of gestation through day‐18 of lactation. On day‐2 of lactation, litters were standardized to three male and three female pups. On day‐18, pups were fasted for 4 hr before tissue and blood collection. Significant changes in serum and liver lipid concentrations and fatty acid patterns were observed in deficient pups. Serum triglycerides, cholesterol and phospholipids and liver triglycerides, cholesterol, and cholesteryl esters were increased. In deficient pups, percentage total fatty acids of 14∶0, 16∶1, 18∶1, 18∶2 from serum lipids were increased; in liver, 14∶0, 18∶2, 18∶3 were increased; 18∶0 and 20∶4 were decreased in both serum and liver. Dam serum lipid levels did not differ between groups. Lipid changes observed in iron‐deficient pups did not consistently reflect the milk, serum or liver lipid patterns observed in dams. Altered lipid composition and fatty acid patterns of iron‐deficient pups thus appear to be of endogenous origin.
Occurrence of octadecenoic fatty acid isomers from hydrogenated fats in human tissue lipid classes
Authors: Ohlrogge J. B. , Gulley R. M. , Emken E. A. 
Published: December 2006

AbstractThe level oftrans‐18∶1 isomers in several isolated lipid classes of human liver, heart, red blood cells and plasma was determined. Phospholipids contained substantially fewertrans‐18∶1 isomers than triglycerides. The double bond distribution of thecis andtrans octadecenoate fraction of triglycerides and phosphatidylcholines from human liver and heart was determined. Whereas the double bond distribution of the triglycerides correlated closely with the pattern found in dietary hydrogenated vegetable oils, the phosphatidylcholine fraction showed evidence of selective incorporation or metabolism of specifictrans positional isomers. In general, isomers with double bonds near the methyl terminus were present at levels higher than expected from their relative abundance in the diet. Refinements in methodology needed to analyze octadecenoate double bond configuration and location in human tissues are presented.
Synthesis of mixed‐acid phosphatidylcholines and high pressure liquid chromatographic analysis of isomeric lysophosphatidylcholines
Authors: Nicholas Allan W. , Khouri Liliane G. , Ellington Joe C. , Porter Ned A. 
Published: December 2006

AbstractA new method for the synthesis of mixed‐chain phosphatidylcholines is reported. Silver ion catalyzed acylation of lysophosphatidylcholines by 2‐thiopyridyl esters occurs rapidly (10 min) at room temperature in organic solvents. Yields of isomerically pure mixed‐chain phosphatidylcholines (>98% isomeric purity) are generally greater than 80%. The reaction proceeds with only 1.5‐ to 2‐fold excess of thiopyridyl ester, thus offering some advantages over existing procedures when precious acylating agents are used. The major disadvantage of the procedure is its sensitivity to water. Phosphatidylcholines having hydroxy fatty acyl groups are prepared by protection of the hydroxyl as the levulinate ester, conversion to the 2‐thiopyridyl ester, acylation, and removal of the levulinate with hydrazine. For purification of lysophosphatidylcholines, a reverse‐phase high pressure liquid chromatographic method for separation of 1‐acylglycerophosphocholines from 2‐acylglycerophosphocholines was developed.
Sulfite‐induced lipid peroxidation
Authors: Lizada M. C. C. , Yang S. F. 
Published: December 2006

AbstractSulfite initiated the peroxidation of linoleic acid and linolenic acid emulsions via a free radical mechanism. Peroxidation of these fatty acids required oxygen and sulfite and occurred with concomitant oxidation of sulfite to sulfate. In reaction mixtures containing linoleic acid, the formation of conjugated diene equaled the formation of hydroperoxide. In reaction mixtures containing linolenic acid emulsions, thiobarbituric acid reactive materials were also formed. Peroxidation was pH‐dependent; peroxidation of linoleic acid proceeded between pH 4 and 7, but linolenic acid peroxidation was significant only if pH was below pH 6. The linoleic acid hydroperoxides thus formed were reduced and methylated to methyl hydroxystearate. Analysis of methyl hydroxystearate by gas chromatographymass spectrometry indicated that sulfite‐induced peroxidation gave rise to the 9‐ and 13‐hydroperoxy isomers. In addition to the hydroperoxides, sulfite adducts were detected. Hydroquinone, butylated hydroxytoluene and α‐tocopherol effectively inhibited both sulfite oxidation and hydroperoxide formation. Conjugated diene formation also was inhibited by 4‐thiouridine, suggesting that the reaction is mediated by the sulfite radical. No significant inhibition was observed with the addition of superoxide dismutase, catalase, or the hydroxyl radical scavengers, mannitol ort‐butanol. A possible mechanism is presented to account for sulfite‐induced peroxidation of linoleic acid.