bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of dietary n−6 and n−3 polyunsaturated fatty acids on blood pressure and tissue fatty acid composition in spontaneously hypertensive rats
Authors: Watanabe Yoshiyasu , Huang Yung‐Sheng , Simmons Valerie A. , Horrobin D. F. 
Published: November 2006

AbstractEffects of dietary n−6 and n−3 fatty acids (FAs) on blood pressure (BP) and tissue phospholipid (PL) FA composition in spontaneously hypertensive (SHR) and normotensive Wistar‐Kyoto (WKY) rats were compared. Male weanling SHR and WKY were fed a fat‐free semisynthetic diet supplemented with 10% (w/w) fats containing (a) 78% 18∶2n−6 (LA‐rich), (b) 20% LA and 55% 18∶3n−3 (LN‐rich), or (c) 11% LA and 3% LN (CON) for seven weeks. Dietary fats did not affect the BP elevation, but significantly altered the FA composition of brain, adrenal gland, renal medulla and cortex PL in SHR. The LA‐rich diet increased n−6 FA while it reduced n−3 FA levels. The levels of 20∶4n−6 were not significantly different between animals fed the LA‐rich and the CON diets. LN‐rich diet increased the levels of n−3 FAs, while it reduced those of n−6 FAs. However, the extent of change was significantly less in SHR than in WKY. In all dietary groups, SHR, as compared to WKY, had a relatively higher level of the 2 series prostaglandin (PG) precursor, 20∶4n−6, and a relatively lower level of the 1 and 3 series PG precursors, 20∶3n−6 and 20∶5n−3. The possibility that the unbalanced eicosanoid FA precursor levels might contribute to the development of hypertension in this animal model is discussed.
A modification of the thiobarbituric acid reaction
Authors: Bidder T. George , Sipka Bona M. 
Published: November 2006

AbstractA simple modification of the thiobarbituric acid reaction, which removes nonspecific chromogenic reaction products, involves incubation at room temperature for 16–20 hr and a column chromatographic step. The chromogen‐concentrating capacity of the latter step is useful for determination of low concentrations of thiobarbituric acid‐reactive materials in biological preparations.
Antioxidant activity of β‐carotene‐related carotenoids in solution
Authors: Terao J. 
Published: November 2006

AbstractThe effect of the antioxidant activity of β‐carotene and related carotenoids on the free radical‐oxidation of methyl linoleate in solution was examined by measuring the production of methyl linoleate hydroperoxides. Canthaxanthin and astaxanthin which possess oxo groups at the 4 and 4′‐positions in the β‐inonone ring retarded the hydroperoxide formation more efficiently than β‐carotene and zeaxanthin which possess no oxo groups. The rates of autocatalytic oxidation of canthaxanthin and astaxanthin were also slower than those of β‐carotene and zeaxanthin. These results suggest that canthaxanthin and astaxanthin are more effective antioxidants than β‐carotene by stabilizing the trapped radicals.
On the isolation of the new fatty acid 6,11‐eicosadienoic (20∶2) and related 6,11‐dienoic acids from the spongeEuryspongia rosea
Authors: Carballeira Nestor M. , Maldonado Maria E. 
Published: November 2006

AbstractThe phospholipid fatty acids from the spongeEuryspongia rosea were studied revealing the presence of the new 6,11‐eicosadienoic (20∶2) acid and the rare 6,11‐octadecadienoic acid (18∶2). The isolation of these 6,11‐dienoic acids reveals the presence of new biosynthetic possibilities in sponges and suggests the presence of an active Δ6 desaturase inE. rosea. Other acids isolated fromE. rosea include 12‐eicosenoic (20∶1) and 17‐tetracosenoic acid (24∶1). The major phospholipids encountered in the sponge were phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylcholine (PC).
Estradiol is a potent inhibitor of the hypotriglyceridemic effect of levonorgestrel in female rats
Authors: Taves Edgar H. , Wolfe Bernard M. J. 
Published: November 2006

AbstractThe progestin, levonorgestrel, when administered to rats intramuscularly, significantly lowered both total and very low density lipoprotein triglyceride concentrations in the blood plasma by 35–40%. This effect was readily abolished by the simultaneous intramuscular administration of estradiol benzoate. Similarly, estradiol‐17β overcame the inhibitory effects of levonorgestrel on the incorporation of [9,10‐3H]palmitate into triglycerides of freshly isolated rat hepatocytes studiedin vitro. However, estradiol alone significantly raised plasma triglycerides by two‐foldin vivo. Estradiol also significantly enhanced (by 9%) the incorporation of [9,10‐3H]palmitate into hepatocyte triglycerides. These results suggest that the effects of estradiol on triglyceride synthesis and concentration dominate over those of levonorgestrel in the rat.
Rates of depletion of linoleic acid from fat depots of selected lines of mice differing in growth rate and adiposity
Authors: Eisen E. J. , Cartwright A. L. , Weller K. M. , Smith K. J. 
Published: November 2006

AbstractRates of depletion and half‐lives of linoleic acid from epididymal, subcutaneous and retroperitoneal fat pads and the residual body were compared among 5 genetically diverse strains of mice: M16, a polygenic obese line developed by selection for high postweaning gain; ICR, a control line from which M16 was derived; H6, a nonobese strain selected for large 6‐week body weight; L6, selected for small 6‐week body weight; and C2 a control line from which H6 and L6 were initiated. Rates of depletion and half‐lives of linoleic acid were obtained on a fat‐free diet following an enrichment period of feeding a diet high in linoleic acid. The M16 mice have an increased capability of synthesizing fat from carbohydrates as shown by a continued increase in fat depot weights when fed the fat‐free diet. The 4 other lines showed no subsequent increase in fat depot weights on the fat‐free diet. Rates of depletion of linoleic acid were significantly different among lines in each of the 4 depots. Ranking of lines for depletion rates was similar among the 3 discrete depots, but a more rapid rate of depletion was observed in subcutaneous and retroperitoneal fat depots than in the epididymal fat depot. Rates of depletion in line M16 were slower than in the ICR control line. Line H6 had a slower rate of depletion than line L6. Line L6 deviated more from the C2 control than did line H6, indicating an asymmetric correlated selection response. The decreased depletion rate of linoleic acid in fat tissue of M16 and H6 mice suggests the possibility that the turnover rates of fatty acids have been reduced in these lines as a result of a reduction in lipolytic activity. The increased depletion rate of linoleic acid in L6 mice suggests that selection for small body size has substantially increased the rate of fat turnover. The experiment demonstrates that genetic differences among lines in fat turnover have accurued as corelated responses to selection for growth rate.
Hypercholesterolemia in rats: Combined effect of high cholesterol diet and female sex steroids
Authors: Fischer G. M. , Swain M. L. 
Published: November 2006

AbstractThe influence of estradiol and a contraceptive steroid combination on plasma cholesterol was studied in female rats on both normal and high‐cholesterol diets which did not contain thiouracil. The high‐cholesterol diet resulted in moderate hypercholesterolemia without weight loss, even with prolonged feeding. Hypercholesterolemia was markedly accentuated in the presence of either endogenous or exogenous sex hormones.
The metabolism of phytosterols in the insectTenebrio molitor: Utilization of 24‐methylenecholesterol and 24,28‐epoxymethylenecholesterol
Authors: Nicotra Francesco , Ronchetti Fiamma , Russo Giovanni 
Published: November 2006

Abstract[23,23,25‐3H3]24‐Methylenecholesterol and the corresponding 24,28‐epoxide are converted into labeled cholesterol by larvae ofTenebrio molitor.
A comparison of the biological properties of of androst‐5‐en‐3β‐ol, a series of (20R)‐n‐alkylpregn‐5‐en‐3β‐ols and 21‐isopentylcholesterol with those of cholesterol
Authors: Nes William R. , Adler John H. , Billheimer Jeffrey T. , Erickson Katherine A. , Joseph John M. , Landrey Josephine R. , Marcaccio‐Joseph Rosemarie , Ritter Karla S. , Conner Robert L. 
Published: November 2006

AbstractThe Δ5‐sterol, androst‐5‐en‐3β‐ol, which has no side chain at C‐17, did not permit molting of the insectHeliothis zea, growth of either the protozoanTetrahymena pyriformis, or the yeastSaccharomyces cerevisiae adapted to anaerobic conditions, nor was the sterol esterified by a mammalian microsomal ACAT preparation. However, the sterol did form a liposome with egg lecithin and, when fed to mice, did inhibit hepatic cholesterol synthesis. 21‐Isopentylcholesterol also formed a liposome but neither supported the growth of the yeast nor was metabolized by the protozoan. When sterols, 20(R)‐n‐alkylpregn‐5‐en‐3β‐ols, with side chains of varying lengths were added to the medium of the protozoan, maximal esterification with fatty acids occurred with the 20(R)‐n‐pentyl derivative, and maximal inhibition of tetrahymanol formation occurred with then‐butyl,n‐pentyl andn‐hexyl derivatives. In all of the assays, cholesterol showed a positive response, either permitting molting or growth, being metabolized, inhibiting sterol or tetrahymanol synthesis, or forming a liposome.
Association of the intestinal brush‐border membrane phospholipase A2 and lysophospholipase activities (phospholipase B) with a stalked membrane protein
Authors: Pind Steven , Kuksis Arnis 
Published: November 2006

AbstractWe have attempted to determine the size and membrane orientation of a recently described rat jejunal brushborder protein possessing phospholipase A2 and lysophospholipase activities (phospholipase B) (Pind, S. and Kuksis, A. [1988]Biochim. Biophys Acta 938, 211–221). The phospholipase A2 and lysophospholipase activities were renatured following nonreducing sodium dodecyl sulphate polyacrylamide gel electrophoresis of the total membrane proteins and were shown to migrate as a component of a protein band having a relative molecular mass of 170 kDa. This band accounted for approximately 1% of the total Coomassie Blue staining proteins. Phospholipase B was also shown to be solubilized from the membranes, in an active form, by a proteolytic digestion with papain. Papain solubilization resulted in a loss of the hydrophobic properties observed for the intact phospholipase. These results suggest that the active site of the phospholipase projects from the luminal surface of the membrane vesicles. In support of this, phospholipase activity towards exogenous, detergent‐solubilized phosphatidylcholine was demonstrated under conditions in which the membranes remained intact. We conclude that the phospholipase B has the characteristics of a stalked, brush‐border membrane protein and may be considered as another digestive enzyme anchored in this membrane.
1‐O‐alk‐1′‐enyl‐2‐acyl and 1‐O‐alkyl‐2‐acyl glycerophospholipids in white muscle of bonitoEuthynnus pelamis (Linnaeus)
Authors: Ohshima Toshiaki , Wada Shun , Koizumi Chiaki 
Published: November 2006

AbstractThe existence of ether‐linked phospholipids, including 1‐O‐alk‐1′‐enyl‐2‐acyl and 1‐O‐alkyl‐2‐acyl‐sn‐glycero‐3‐phosphocholines and ethanolamines in bonitoEuthynnus pelamis (Linnaeus) white muscle, was investigated by gas chromatography and gas chromatography‐mass spectrometry. Chemical ionization (iso‐butane) mass spectrometry of trimethylsilyl ethers derived from the corresponding ether‐linked glycerophospholipids proved effective not only for determining molecular weights but also for structural identification based on the ions [M−R]+, [M−RO]+ and [M+1]+. 1‐O‐Alk‐1′‐enyl‐2‐acyl‐sn‐glycero‐3‐phosphocholine and ethanolamine accounted for 3.0–6.0% and 3.6–7.6% of the total glycerophospholipids, respectively. 1‐O‐Alkyl‐2‐acyl‐sn‐glycero‐3‐phosphocholine and ethanolamine were also determined for one fish and accounted for 1.4% and 0.6% of the total glycerophospholipids, respectively. The predominant long chains in thesn‐1 position of the glycerol moieties were 16∶0, 18∶0 and 18∶1 in the case of the alkenylacyl and alkylacyl components. Fatty acid distribution of individual glycerophospholipids was also determined.
Changes in lipid composition of liver microsomes and fatty acyl‐CoA desaturase activities induced by medium chain triglyceride feeding
Authors: Periago José L. , Pita María L. , Sanchez del Castillo María A. , Caamaño Guillermo , Suárez María D. 
Published: November 2006

AbstractChanges in fatty acid composition, microsomal Δ9‐ and Δ6‐desaturase activities and liver contents of cholesterol and phospholipids were studied in rats fed medium chain triglyceride‐supplemented diets. Weanling rats were divided into four groups and fed for three weeks a basal diet with different 10%‐fat supplements: corn oil, medium chain triglyceride‐corn oil, olive oil and medium chain triglyceride‐olive oil. The highest relative content of saturated fatty acids corresponded to corn oil‐fed animals. Both monounsaturated fatty acid content and Δ9‐desaturase activity were higher in the animals fed olive oil diets than in corn oil‐fed rats. The long chain polyunsaturated fatty acids of the n−3 series were increased in the olive oil and medium chain triglyceride‐olive oil‐fed groups probably due to the lower linoleic/α‐linolenic ratios found in these two diets. The cholesterol/phospholipid molar ratio was unaffected by diet and the unsaturation index was only slightly changed in the four groups. Thus, some mechanism may be operative under these conditions to maintain the homeostasis of the membrane.
Molecular species of glycerophospholipids and sphingomyelins of human erythrocytes: Improved method of analysis
Authors: Myher J. J. , Kuksis A. , Pind S. 
Published: November 2006

AbstractThis study reports the application of modern methods of molecular species analysis in determination of the structure of both major and minor glycerophospholipids and sphingomyelins of human erythrocytes. Individual phospholipid classes were resolved from total lipid extracts by thin‐layer chromatography. Diradylglycerols were released by phospholipase C and converted into trimethylsilyl ethers, which were resolved into the alkenylacyl, alkylacyl and diacylglycerol subclasses by normal phase high performance liquid chromatography. Molecular species of diradylglycerols and ceramides were quantitated according to carbon and double bond number by gas liquid chromatography using a fused silica capillary column wall‐coated with bonded RTx‐2330. The molecular species of ceramides were determined by GC/MS. The diradyl glycerophosphocholines contained 93.0% diacyl, 4.6% alkylacyl and 2.5% alkenylacyl, white the diradyl glycerophosphoethanolamines were made up of 48.8% diacyl, 47.8% alkenylacyl and 3.4% alkylacyl subclasses. Analysis of the molecular species showed that the long chain polyunsaturated acids were mainly combined with C16 in all diradyl GPC subclasses and in diacyl GPE, while in the alkylacyl and alkenylacyl GPE and in diacyl glycerophosphoinositol and diacyl glycerophosphoserine they were combined mainly with C18 saturated fatty chains. In addition to the C16 and C18 alkyl and alkenyl, the ether fractions also contained significant proportions of C20, C22 and C24 chains. The molecular species of the ceramide moieties of the SPH were made up largely of mono‐ and diunsaturated species. Over 200 molecular species were identified and quantitated in a representative sample of human red blood cells.
Eicosapentaenoic and arachidonic acid: Comparison of metabolism and activity in murine epidermal cells
Authors: Belury Martha A. , Patrick Kelly E. , Locniskar Mary , Fischer Susan M. 
Published: November 2006

AbstractThe biological activity, including metabolism and modulation of ornithine decarboxylase activity and DNA synthesis, of arachidonic acid (AA) and eicosapentaenoic acid (EPA) were compared in epidermal cells from SENCAR mice. Radiolabelled AA and EPA were found to be similarly incorporated into and released from membrane phospholipids of unstimulated cultures. However, when cells were stimulated with the tumor promoter 12‐0‐tetradecanoylphorbol‐13‐acetate (TPA), the release of AA was significantly higher than the release of EPA. The extent of metabolism of AA and EPA to prostaglandins was determined in both freeze‐thawed cell preparations and in viable cultured cells. In the freeze‐thawed preparations, use of AA as a substrate resulted in significantly more PGF than when EPA was used as the substrate. However, more PGE3 was formed than PGE2. PGD levels were the same for either fatty acid precursor. Prostaglandin production was also determined in viable cultured cells since other influences such as phospholipase A2 activity can modify prostaglandin production. Control cultures prelabelled with either AA or EPA produced similar amounts of the respective PGF, PGE, and PGD. However, TPA‐stimulated cultures produced significantly higher amounts of each prostaglandin in cultures prelabelled with AA compared to cells prelabelled with EPA. HETE or HEPE production was the same both for cultured cells prelabelled with AA or EPA and for homogenates from uncultured cells incubated directly with the radiolabelled fatty acids. TPA‐induced ornithine decarboxylase (ODC) was significantly higher in AA‐treated cultures compared to EPA‐treated cultures. AA supports DNA synthesis to a greater extent than EPA, either alone or in the presence of TPA. These findings suggest that AA and EPA do not have equivalent biological activity in mouse epidermal cells.
The hepatocellular transport of sulfobromophthalein‐glutathione by clofibrate treated, perfused rat liver
Authors: Sorrentino Dario , Weisiger Richard A. , Bass Nathan M. , Licko Vojtech 
Published: November 2006

AbstractThe hypolipidemic drug clofibrate is known to affect the hepatic transport of various organic anions including bilirubin, fatty acids and sulfobromophthalein. Changes in the rate of metabolism and/or intracellular transport have been claimed responsible for the effect. To evaluate these possibilities, the transport of sulfobromophthalein‐glutathione, a model compound that does not require metabolism for biliary excretion, was studied in perfused livers isolated from clofibrate‐treated and control rats. Cytosolic fatty acid binding protein and glutathione S‐transferase activity were also measured. Clofibrate treatment significantly increased liver weight; as a result glutathione S‐transferase activity (toward 1‐chloro‐2,4‐dinitrobenzene) fell if expressed per gram of liver (4560±420 (SE) vs 7010±260 nmoles/min for clofibrate treated and controls respectively, p<0.002), but was unchanged when expressed per total liver (60.8±6.5 vs 64.6±3.5 μmoles/min for clofibrate and controls p>0.5). Irrespective of how it was expressed fatty acid binding protein was significantly increased by the drug treatment. Steady state sulfobromophthalein‐glutathione removal velocity was saturble with increasing concentrations of sulfobromophthalein‐glutathione in both control and clofibrate‐treated livers. Steady state extraction ratio, as well as Vmax and Km for removal, did not differ between the two groups. In keeping with other observations, these data collectively indicate that the hepatic steady state removal of nonmetabolized compounds is not affected by clofibrate. Because the concomitant decrease in glutathione S‐transferase activity only reflects an opposite change in liver weight, it remains to be determined whether clofibrate alters the hepatic transport of sulfobromophthalein and other compounds that are conjugated with glutathione solely by changing their rate of metabolism.
Increased plasma triglyceride secretion in EFA‐deficient rats fed diets with or without saturated fat
Authors: Williams M. A. , Tinoco J. , Hincenbergs I. , Thomas B. 
Published: November 2006

AbstractMetabolic responses to essential fatty acid‐deficiency in rats include an increased rate of triglyceride secretion into the plasma, a large reduction in the HDL1 plasma lipoprotein concentration, and increased concentrations of liver triacylglycerols and cholesteryl esters. Because of differences in the types of EFA‐deficient diets used, it is not clear whether these responses were solely due to the absence of EFA from the diet or whether saturated fat, or differences in acyl group chain length in this fat, might be responsible. Therefore, we fed rats diets differing only in amounts and kinds of fat, and measured triacylglycerol secretion rates and liver concentrations of triacylglycerols and cholesteryl esters, for comparison with our earlier measurements of plasma high density lipoprotein subpopulations in rats fed exactly the same diets. The purified diets contained either no fat, 5% by weight hydrogenated coconut oil, 5% hydrogenated cottonseed oil, or each of these three diets supplemented with 1% safflower oil, or 5% corn oil. We also fed some rats a nonpurified stock diet for comparison with literature reports. The present results indicate that the metabolic responses to essential fatty acid deficiency described above are definitely due to essential fatty acid‐deficiency and not to the presence or chain length of acyl groups in saturated fat in the diet.
The precursors of fecapentaenes: Purification and properties of a novel plasmalogen
Authors: Van Tassell R. L. , Piccariello T. , Kingston D. G. I. , Wilkins T. D. 
Published: November 2006

AbstractFecapentaene‐12 and fecapentaene‐14 are genotoxic polyunsaturated ether‐lipids produced by the colonic microflora in humans and pigs. Although the fecapentaenes have been extensively characterized, little is known about the nature of the precursors from which they are produced. We purified one form of these precursors from feces of an individual who excreted high levels of fecapentaene‐12 and its precursors. Purification was carried out by a series of extractions and precipitation in organic solvents followed by silica and amine high performance liquid chromatography. The purified precursor had identical UV spectral characteristics as the fecapentaenes indicating that it contained the same ether‐linked pentaenyl functional group. However, it was not mutagenic. The precursor was amphiphilic in nature, behaving like a synthetic “model” ether‐phospholipid on silica and C18 thin layer chromatography. When incorporated into phosphatidylcholine micelles it could be hydrolyzedin vitro by a combination of lipase and phospholipase C to fecapentaene‐12. Our findings indicate that the general structure of this precursor is that of a phospholipid, specifically a plasmalogen—the exact structures of which remain to be determined.
Fatty acid hydroperoxide isomerase inSaprolegnia parasitica: Structural studies of epoxy alcohols formed from isomeric hydroperoxyoctadecadienoates
Authors: Hamberg Mats 
Published: November 2006

AbstractThe major part (80%) of the fatty acid hydroperoxide isomerase activity present in homogenates of the fungus,Saprolegnia parasitica, was localized in the particle fraction sedimenting at 105,000×g.13(S)‐Hydroperoxy‐9(Z),11(E)‐octadecadienoic acid and 9(S)‐hydroperoxy‐10(E),12(Z)‐octadecadienoic acid were both good substrates for the particle‐bound hydroperoxide isomerase. The products formed from the 13(S)‐hydroperoxide were identified as an α,β‐ and a γ,δ‐epoxy alcohol, i.e., 11(R),12(R)‐epoxy‐13(S)‐hydroxy‐9(Z)‐octadecenoic acid and 9(S),10(R)‐epoxy‐13(S)‐hydroxy‐11(E)‐octadecenoic acid, respectively. The 9(S)‐hydroperoxide was converted in an analogous way into an α,β‐epoxy alcohol, 10(R),11(R)‐epoxy‐9(S)‐hydroxy‐12(Z)‐octadecenoic acid and a γ,δ‐epoxy alcohol, 12(R),13(S)‐epoxy‐9(S)‐hydroxy‐10(E)‐octadecenoic acid.9(R,S)‐Hydroperoxy‐10(E),12(E)‐octadecadienoic acid and 13(R,S)‐hydroperoxy‐9(E),11(E)‐octadecadienoic acid were poor substrates for theS. parasitica hydroperoxide isomerase. Experiments with 13(R,S)‐hydroperoxy‐9(Z),11(E)‐octadecadienoic acid showed that the 13(R)‐hydroperoxy enantiomer was slowly isomerized by the enzyme. The major product was identified as α,β‐epoxy alcohol 11(R),12(R)‐epoxy‐13(R)‐hydroxy‐9(Z)‐octadecenoic acid.