bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in ether‐linked phospholipids in rat kidney by dietary α‐linolenic acidin vivo
Authors: Park Jin H. , Park Eek J. , Kim Kye S. , Yeo Young K. 
Published: November 2006

AbstractWe investigated the effects of perilla oil containing a high level of α‐linolenic acid onin vivo phospholipid metabolism, particularly three subclasses of choline glycerophospholipids (CGP) and ethanolamine glycerophospholipids (EGP), in rat kidney. After three weeks of feeding, a significantly lower proportion (by 35%) of the alkylacyl subclass of CGP was found in the perilla oil, as compared to corn oil‐fed animals. The alkylacyl species of EGP was also higher in the perilla oil than in the corn oil‐fed animals. These alterations were accompanied by a remarkably lower proportion of arachidonic acid and a higher level of eicosapentaenoic acid (EPA) in all six subclasses of CGP and EGP in the perilla oil‐fed animals. The levels of linoleic acid were even higher in the diacyl subclasses of CGP and EGP in the perilla oil group, suggesting that desaturase and elongase enzymes prefer n−3 to n−6 fatty acids as substrates for diacyl species. These data are useful in defining the effects of α‐linolenic acid on the biosynthesis of renal phospholipids and on the replacement of n−6 with n−3 fatty acids in the six CGP and EGP subclasses.
Effects of dietary oil related to the toxic oil syndrome on the lipids of guinea pig liver microsomes
Authors: de la Casa E. , Pérez‐González N. , Sánchez‐Bernal C. , Llanillo M. 
Published: November 2006

AbstractThe potential effects of oil specimens related to cases of toxic oil syndrome (TOS) on the liver microsomal lipid composition from guinea pigs were investigated. For four weeks, animals were fed diets supplemented with either “case oil” (oil related to cases of TOS) or “control oil” (oil unrelated to cases of TOS), either previously heated or not. Results were compared with those from guinea pigs fed the same diet with no oil. The administration of case oil produced changes in liver microsomal lipid composition. Statistically significant differences were also found between heated case and heated control oils. The cholesterol/phospholipid molar ratios and the major phospholipid class distribution were unaffected under these diet conditions. However, increases in the relative contents of linoleic and arachidonic acids and, simultaneously, a reduction in palmitic and palmitoleic acid levels were observed by diet effects. Heated oil administration decreased the saturated/unsaturated ratios in all cases. Our data suggest that changes observed in the fatty acid composition are attributable to the free fatty acid contents of administered oils. The toxic constituents of case oil seem to be able to alter the liver microsomal lipid composition.
High‐performance liquid chromatography with light‐scattering detection and desorption chemical‐ionization tandem mass spectrometry of milk fat triacylglycerols
Authors: Spanos George A. , Schwartz Steven J. , van Breemen Richard B. , Huang Chien‐Hua 
Published: November 2006

AbstractThe utility of reverse‐phase high‐performance liquid chromatography (HPLC), desorption chemical‐ionization mass spectrometry (DCI‐MS) and tandem mass spectrometry (MS/MS) for the characterization of triacylglycerols in complex mixtures has been further explored. Triacylglycerols of anhydrous bovine milk fat were separated by using two reversephase C18 HPLC columns, and eluents were monitored with an evaporative light‐scattering detector. Fifty‐eight fractions were resolved and analyzed by positive ion isobutane DCI‐MS. The formation of protonated molecules and of major fragments corresponding to the random loss of any one of the constituent fatty acids readily identified acyl carbon numbers and the number of double bonds within each fatty acid. MS/MS was only required when the original mass spectra indicated the presence of more than one triacylglycerol or of impurities in a fraction. Protonated molecules produced by DCI were fragmented using high energy collisional activation, and the resulting ions were detected by MS/MS. Odd‐chain triacylglycerols were also readily distinguished using this methodology. The positive ion DCI and MS/MS techniques described here demonstrate the usefulness of this approach for the characterization of triacylglycerols in complex mixtures.
Nonmembrane associated dolichol in rat liver
Authors: Löw P. , Peterson E. , Edlund C. , Brunk U. , Appelkvist E. L. 
Published: November 2006

AbstractThe distribution of dolichol in rat liver was studied. Upon high‐speed centrifugation, 9% of the total tissue dolichol was recovered in the supernatant. Dolichol was enclosed in vesicles and in lipidic particles which were isolated by gel filtration and density gradient centrifugation. The particles had a diameter of 20 nm and contained dolichol, ubiquinone, cholesterol, phospholipid and some protein. Similar particles were recovered upon incubation of isolated hepatocytes with liposomes containing dolichol. From the lysosomal lumen, lipid particles containing dolichol, ubiquinone, cholesterol and phospholipid, but no protein, were isolated. The diameter of the particles was 20–40 nm with a molecular weight of 130 kDa. Puromycin treatment inhibited protein synthesis, but did not affect dolichol transfer from the endoplasmic reticulum to lysosomes, suggesting that the transfer is not mediated by newly synthesized apoprotein. The results indicate that a sizeable portion of the total cellular dolichol is present in cytoplasm and in lysosomal lumen. Furthermore, dolichol probably participates in the translocation process.
Compartmental study of rat renal phospholipid metabolism
Authors: Sterin‐Speziale Norma , Kahane Veronica L. , Setton Clara Patricia , Fernandez Maria del Carmen , Speziale Emir H. 
Published: November 2006

AbstractPhospholipid content and metabolism were studied in rat renal papillary, medullary and cortical slices. The highest concentration of phospholipids was found in cortex and the lowest in papilla samples (ratio cortex/medulla, 1.3; cortex/papilla, 3.7). The profile of the various phospholipids was different depending on the zone. The most important difference was the relative concentrations of sphingomyelin (CerPCho) and phosphatidylinositol (PtdIns) with ratios for PtdIns/CerPCho of 5.0, 3.3 and 2.5 in papilla, medulla, and cortex, respectively. In the three zones, PtdIns showed the highest specific activity for [2‐14C]glycerol and [1‐14C]arachidonic acid incorporation. By contrast, a higher amount of [1‐14C]palmitic acid was incorporated into phosphatidylcholine than into any other phospholipid. The various radioactive precursors were only poorly incorporated into phosphatidylethanolamine. No radioactivity was associated with phosphatidylserine. The papilla possesses the most active phospholipid metabolism of all the pathways studied.
Effect of human mammary MX‐1 tumor on plasma free fatty acids in fasted and fasted‐refed nude mice
Authors: Lin Chu , Blank Edward W. , Ceriani Roberto L. , Baker Nome 
Published: November 2006

AbstractWe hypothesized that tumor‐bearing (TB) nude mice, because they are reported to have no detectable, circulating tumor necrosis factor (TNF)/cachectin, would regulate their plasma free fatty acid (FFA) levels normally when fasted and refed. We compared levels of individual plasma FFA in response to fasting (24 hr) and to refeeding (for 20 hr after fasting) a fat‐free, 65% sucrose diet in control, nude mice and in mice bearing 1.3±0.4 g MX‐1 tumors. Total plasma FFA levels were typically high in 24‐hr fasted mice [mean concentrations in μM±SE (n); controls 515±63 (6); TB, 625±63 (6)]. FFA levels were reduced by 65% in each group in response to refeeding. Each major plasma FFA species fell in response to refeeding, except arachidonate, which did not change significantly (fastedvs. fasted‐refed concentrations) in either controls or TB mice. In refed mice, the molar FFA ratio of oleate to linoleate rose; however, that of oleate to arachidonate fell markedly. TB nude mice had normal appetites. We conclude that all species of FFA were mobilized from adipose tissue in a normal manner in TB nude mice; therefore, regulation of adipose triacylglycerol fatty acid mobilization (as plasma FFA) by dietary sugar is probably not affected by MX‐1 tumor growth in these mice. Our findings are consistent with the hypothesis that nude mice may be unable to secrete TNF/cachectin in response to tumor growth, but they do not establish whether or not endogenous, circulating TNF/cachectin increases FFA mobilization in any TB animal.
Glutathione and antioxidants protect microsomes against lipid peroxidation and enzyme inactivation
Authors: Hu Miao‐Lin , Tappel Al L. 
Published: November 2006

AbstractThe study investigated the relationship between lipid peroxidation and enzyme inactivation in rat hepatic microsomes and whether prior inactivation of aldehyde dehydrogenase (ALDH) exacerbated inactivation of other enzymes. In microsomes incubated with 2.5 μM iron as ferric sulfate and 50 μM ascorbate, ALDH, glucose‐6‐phosphate (G6Pase) and cytochrome P450 (Cyt‐P450) levels decreased rapidly and concurrently with increased levels of thiobarbituric acid‐reactive substances. Microsomal glutathioneS‐transferase and nicotinamide adenine dinucleotide phosphate‐cytochromec reductase were little affected during 1 hr of incubation. Addition of reduced glutathione partially protected, andN,N′‐diphenyl‐p‐phenylenediamine and butylated hydroxytoluene completely protected microsomes against inactivation of ALDH, G6Pase and Cyt‐P450, as well as lipid peroxidation induced by iron and ascorbate. ALDH was more susceptible than G6Pase to inactivation by iron and ascorbate, and was thus an excellent marker for oxidative stress. Inhibition of ALDH by cyanamide injection of rats exacerbated the inactivation of G6Pase in microsomes incubated with 0.1 mM, but not 25 μM 4‐hydroxynonenal (4‐HN). 4‐HN did not stimulate lipid peroxidation. Thus, 4‐HN may play a minor role in microsomal enzyme inactivation. In contrast, lipid, peroxyl radicals play an important role in microsomal enzyme inactivation, as evidenced by the prevention of both lipid peroxidation and enzyme inactivation by chain‐breaking antioxidants.
Formation of formaldehyde and malonaldehyde by photooxidation of squalene
Authors: Yeo H. C. H. , Shibamoto T. 
Published: November 2006

AbstractFormaldehyde and malonaldehyde were identified upon exposure of squalene to ultraviolet (UV) irradiation at 300 nm. Formaldehyde was derivatized by reaction with cysteamine to form thiazolidine; malonaldehyde was derivatized by reaction withN‐methylhdyrazine to produceN‐methylpyrazole. The derivatives were subsequently analyzed with a gas chromatography equipped with a fused silica capillary column and a nitrogen/phosphorus detector. The levels of formaldehyde and malonaldehyde produced increased with irradiation time. The amount of formaldehyde produced reached a maximum of 3.40 nmol/mg squalene after 7 hr irradiation; the maximum amount of malonaldehyde generated, 0.92 nmol/mg, was found after 5 hr of irradiation. Prior to this study, formaldehyde had not been reported as a photoproduct of squalene. Acetaldehyde and acetone were also detected in the irradiated squalen,, which may be formedvia a 6‐methyl‐5‐hepten‐2‐one intermediate. 6‐Methyl‐5‐hepten‐2‐one can also undergo breakdown to form malonaldehyde.
Acute toxicity oftrans‐5‐hydroxy‐2‐nonenal in fisher 344 rats
Authors: Nishikawa Akiyoshi , Sodum Rama , Chung Fung‐Lung 
Published: November 2006

AbstractThe potential toxicity oftrans‐4‐hydroxy‐2‐nonenal (HNE), a product formedin vivo during lipid peroxidation, which is also present in foods, was investigated in Fisher 344 rats. Five groups of five male rats each were given by gavage 1000, 300, 100, 30 or 10 mg/kg body weight HNE dissolved in 0.5 mL corn oil. The sixth group, the control, received corn oil alone. Two rats died 6 and 8 hr after being treated with 1000 mg/kg HNE. These two rats showed extensive acute tubular necrosis of the kidney, but had very little liver damage. Diffuse liver cell necrosis was observed in a dose dependent manner in all the rats killed 14 days after treatment, whereas renal change was mild. Interestingly, body weight of the lowest dosage group was significantly higher than that of the control group at termination of the experiment. The results of this study show that HNE has almost the same toxicity as other enals, such astrans‐2‐heptenal, and that kidney and liver are the main organs affected by toxicity of HNE. Although animals may have efficient defense systems, such as glutathione, to detoxify low to moderate dosages of HNE, at high doses of HNE this defense system is overwhelmed, resulting in serious renal and hepatic damage.
Preparation and properties ofgem‐dichlorocyclopropane derivatives of long‐chain fatty esters
Authors: Lie Ken Jie Marcel S. F. , Wong C. F. 
Published: November 2006

AbstractMethyl oleate (18∶1) and linoleate (18∶2) were readily transformed to the correspondinggem‐dichlorocyclopropane derivatives in high yield, using triethylbenzylammonium chloride as the phase‐transfer catalyst in the presence of aqueous NaOH and CHCl3. Reaction of dichlorocarbene with methyl 12‐hydroxystearate furnished methyl 12‐chlorostearate (49%) and 12‐O‐formylstearate (19%). The hydroxy group in methyl ricinoleate was protected (O‐tetrahydropyran‐2′‐yl) prior to dichlorocyclopropanation of the ethylenic bond. Removal of the protecting group allowed the hydroxy group to be converted to a chloride,O‐acetyl, azido orO‐formyl function. Treatment of methyl ricinoleate with thionyl chloride, followed by the reaction with dichlorocarbene gave the corresponding 12‐chloro‐dichlorocyclopropane derivative. The dichlorocyclopropane derivative of oleic acid was transformed to a C19 allenic fatty acid when treated witht‐butyl lithium. However, the remaining dichlorocyclopropane derivatives, containing an additional functional group in the alkyl chain, failed to yield the corresponding allenic derivatives. All derivatives were characterized by a combination of spectroscopic and chromatographic techniques, including infrared,1H nuclear magnetic resonance (NMR), and13C NMR spectroscopy.
Measurement of bile acid synthesis in man by release of14CO2 from [26‐14C]cholesterol: Comparison to isotope dilution and assessment of optimum reference cholesterol specific activity
Authors: Mitchell John C. , Stone Bradford G. , Duane William C. 
Published: November 2006

AbstractBile acid synthesis can be measured as release of14CO2 from [26‐14C]cholesterol divided by cholesterol specific activity, but this method has not been validated in human subjects. We made twelve comparisons of this CO2 method to standard isotope dilution in six normal subjects and found a mean discrepancy of 6%. Linear regression analysis of one value with respect to the other revealed a correlation coefficient of 0.83 (P<0.001), a Y‐intercept close to zero (−4.98) and a slope close to 1 (1.06), suggesting good correspondence between the two methods. To assess the potential for error arising from use of serum cholesterol to estimate specific activity of cholesterol used for bile acid synthesis, we compared synthesis measured using serum free cholesterol specific activity to that measured using bile cholesterol specific activity, which is known to be near isotopic equilibrium with the precursor pool used for bile acid synthesis. Synthesis calculated in these two ways differed by less than 10%. The data indicate that the CO2 method using either serum or bile cholesterol specific activity provides a valid estimate of bile acid synthesis in man.
Two novel naturally occurring α‐methoxy acids from the phospholipids of two caribbean sponges
Authors: Carballeira Néstor M. , Sepúlveda Juan A. 
Published: November 2006

AbstractThe novel (5Z)‐2‐methoxy‐5‐hexadecenoic acid (1) was identified in the phospholipids of the spongeTethya crypta while the also novel acid (6Z)‐2‐methoxy‐6‐hexadecenoic acid (2) was found in the phospholipids of the Caribbean spongeSpheciospongia cuspidifera. The methoxy‐fatty acids were mainly associated with phosphatidylethanolamine. The double bond positions were determined by gas chromatography/mass spectrometry on the corresponding dimethyl‐disulfide adducts and the double bond stereochemistry was ascertained by gas chromatography/Fourier transform infrared spectroscopy. The fatty acid composition of the two sponges is reported.
Occurrence of wax esters and 1‐O‐alkyl‐2,3‐diacylglycerols in goat epididymal sperm plasma membrane
Authors: Rana Ajay P. S. , Majumder Gopal C. , Misra Suniti , Ghosh Amitabha 
Published: November 2006

AbstractTwo unusual lipid classes were detected by thin‐layer chromatography in the neutral lipids derived from goat cauda‐epididymal sperm plasma membrane. The lipids were identified as wax esters and 1‐O‐alkyl‐2,3‐diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/1H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C14 to C22. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing 30% of the total fatty acids. The alcohols of wax ester were all saturated with C20–C29 carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec‐9′‐enyl glycerol ethers.
Effects of lovastatin on hepatic fatty acid metabolism
Authors: Guzmán Manuel , Cortés Josefa P. , Castro José 
Published: November 2006

AbstractThein vitro andin vivo effects of lovastatin on fatty acid metabolism were studied in isolated rat hepatocytes. When addedin vitro to cell incubations, lovastatin stimulatedde novo fatty acid synthesis and acetyl‐CoA carboxylase activity, whereas fatty acid synthase, activity was unaffected. Lovastatin depressed palmitate, but not octanoate, oxidation. This may be attributed to the lovastatin‐induced increase, in intracellular malonyl‐CoA levels, as no concomitant changes of carnitine palmitoyltransferase I (CPT‐I) specific activity was detected. Lovastatin had no effect on the synthesis and secretion of triacylglycerols and phospholipids in the form of very low density lipoproteins (VLDL). When rats were fed a diet supplemented with 0.1% (w/w) lovastatin for one week, both acetyl‐CoA carboxylase activity andde novo fatty acid synthesis were reduced compared to pair‐fed controls, whereas fatty acid synthase activity was unaffected. Palmitate oxidation was enhanced in the lovastatin‐fed group. There was an increase in CPT‐I activity but no change in intracellular concentration of malonyl‐CoA. Lovastatin feeding and no significant effect either on the esterification of exogenous palmitic acid into both cellular and VLDL triacylglycerols and phospholipids or on hepatic lipid accumulation. Thein vitro andin vivo effects of lovastatin were not significantly different between periportal and perivenous hepatocytes. The results indicate that: (i) the administration of lovastatin increased the fatty acid‐oxidative capacity of the liver at the expense of its lipogenic capacity, (ii) the rate ofde novo cholesterol synthesis did not seem to be a limiting factor in the synthesis and secretion of VLDL and (iii) lovastatin produced opposite effects on hepatic fatty acid metabolismin vitro andin vivo.
Vitamin E deficiency in dogs does not alter preferential incorporation ofRRR‐α‐tocopherol compared withall rac‐α‐tocopherol into plasma
Authors: Traber Maret G. , Pillai Shreekumar R. , Kayden Herbert J. , Steiss Janet E. 
Published: November 2006

AbstractThe plasma and lipoprotein transport ofRRR andall rac‐α‐tocopherols, labeled with different amounts of deuterium [2R,4′R,8′R‐α‐[5‐C2H3]tocopheryl acetate (d3RRR‐α‐tocopheryl acetate] and 2RS, 4′RS, 8′RS‐α‐[5,7‐(C2H3)2]tocopheryl acetate (d5all rac‐α‐tocopheryl acetate), was studied in adult beagle dogs that had been fed a vitamin E‐deficient (−E; two dogs) or supplemented (+E; two dogs) diet for two years. We set out to test the hypothesis that the activity of the hepatic tocopherol binding protein (which is thought to preferentially incorporateRRR‐α‐tocopherol into the plasma) is up‐regulated by vitamin E deficiency. Labeled α‐tocopherols increased and decreased similarly in plasma of both −E and +E dogs. Irrespective of diet,d3RRR‐α‐tocopherol was preferentially secreted in plasma. Thus, vitamin E deficiency in dogs does not markedly increase the apparent function of the hepatic tocopherol binding protein. We also studied vitamin E transport in a German Shepherd dog with degenerative myelopathy (DM). Based on the coincident appearance ofd3RRR‐α‐tocopherol in plasma and chylomicrons, we suggest that the abnormality in DM may be associated with abnormal vitamin E transport resulting from an impaired function of the hepatic tocopherol binding protein.
Effect of maternal dietary arachidonic or linoleic acid on rat pup fatty acid profiles
Authors: Lien Eric L. , Boyle Fran G. , Yuhas Rebecca J. , Kuhlman Charles F. 
Published: November 2006

AbstractRapidly growing neonatal mammals accrete relatively large quantities of long chain (≥C20) polyunsaturated fatty acids (LCP) in membrane phospholipids. We have examined accumulation of ω6 LCP in suckling neonatal rat pups during the first 14 d of life when their dams received essential fatty acids in the form of triglycerides containing linoleic acid or arachidonic acid. Dietary levels of these fatty acids were either 1 or 5% of total dietary fatty acids. The fatty acid profile of pup stomach contents (composed solely of the dams' milk) and plasma lipids, as well as liver and brain phospholipids, were determined. Stomach linoleic and arachidonic acid levels reflected the diet of the dams. Pup plasma and liver arachidonic acid levels increased progressively from the group receiving 1% linoleic acid to 5% linoleic acid and from 1% arachidonic acid to 5% arachidonic acid. Interestingly, brain phosphatidylethanolamine and phosphatidylcholine arachidonic acid levels were more stable than plasma or liver levels. These results suggest that the brain may be capable of either selective transport of ω6 LCP or chain elongation/desaturation of linoleic acid. These data indicate that care must be exercised when adding LCP to infant formula since widely divergent accretion rates of arachidonic acid may occur in various tissues.
Abnormal plasma lipids of patients withRetinitis pigmentosa
Authors: Holman R. T. , Bibus D. M. , Jeffrey G. H. , Smethurst P. , Crofts J. W. 
Published: November 2006

AbstractRetinitis pigmentosa (RP) is a hereditary retinal degeneration of unknown etiology, resulting in progressive night blindness, loss of peripheral vision, abnormal retinal pigmentation and reduced electroretinographic response. Docosahexaenoic acid (22∶6ω3) is found in high concentration in the rod outer segment membranes of the retina. Previous reports of low 22∶6ω3 in blood lipids or phospholipids in RP patients prompted us to evaluate the complete fatty acid (FA) profiles of plasma phospholipids (PL), cholesteryl esters, triglycerides (TG) and nonesterified fatty acids (NEFA) in ten patients with RP. In the PL fraction, we found significantly depressed levels of 22∶6ω3, 22∶5ω3, total ω3, 22∶5ω6, 22∶4ω6 and total ω6 polyunsaturated FA (PUFA), and elevated total saturated acids. Plasma TG showed normal levels of PUFA, normal total saturated FA and total monounsaturated FA. The NEFA fraction showed significant elevation in total saturated FA with depressed total ω6 PUFA. Evidence is accumulating that RP is associated with abnormal PUFA and lipid metabolism.