bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolism of peripheral nerve monogalactosylceramides
Authors: Yao Jeffrey K. 
Published: November 2006

AbstractThe metabolism of hydroxy galactocerebrosides (GalCe‐OH) and nonhydroxy galactocerebrosides (GalCe) was investigated during the nerve development, degeneration and regeneration by endoneurial injection of [14C]acetate and byin vitro incubation of rat sciatic endoneurium with [14C]acetate, [3H]galactose or [3H]glucose. After endoneurial microinjection, [14C]acetate was found to be incorporated first into GalCe‐OH and later, and to a much lesser degree, into GalCe. The ratio of14C‐labeled GalCe‐OH to GalCe decreased with time and remained fairly constant after 4 hr. On the other hand,in vitro incorporation of [14C]acetate resulted in higher14C‐labeling in GalCe and monogalactosyl diacylglycerol (MGDG) and lower14C‐labeling in GalCe‐OH, diminishing with incubation time. After 24 hr, only GalCe and MGDG were labeled. When [3H]galactose or [3H]glucose, instead of [14C]acetate, were used as precursorin vitro, a similar preference for labeling of GalCe‐OH was demonstrated in regenerating nerve. These data suggest that hydroxy fatty acids and hydroxy ceramides are the preferred substrates in peripheral nervous system for the sphingosine acyltransferase and the UDP‐galactose:ceramide galactosyltransferase reactions, respectively. The α‐hydroxylation system did not appear to be fully functional underin vitro conditions. The biosynthesis of GalCe‐OH was greatly enhanced during nerve fiber regeneration and decreased rapidly with increasing age. This suggests that a close interrelation exists between α‐hydroxylation and peripheral nerve myelination.
Effect of aging and dietary restriction on bile acid metabolism in rats
Authors: Ferland G. , Tuchweber B. , Perea A. , Yousef I. M. 
Published: November 2006

AbstractThe aim of the present study was to determine whether increased output of phospholipid in bile during aging may be due to alteration of bile acid composition and stimulated hydrophobic bile acid formation. In female Sprague‐Dawley rats we examined the influence of aging and life long dietary restriction (60% of thead libitum intake) on bile flow, total bile acid secretion, bile acid composition and conjugation pattern, as well as phospholipid output. Rats were cannulated at 3.5, 8–12 and 24–27 months of age and bile collected for analysis. With age, there was a significant reduction in bile flow and total bile acid secretion, however, phospholipid output increased. Restriction of dietary intake exerted a beneficial effect on the age‐related decline in bile formation. Studies of bile composition indicated that 12α‐hydroxylated bile acids (cholic acid and deoxycholic acid) secretion decreased in aged rats compared to 3.5‐month‐old rats. This was associated with a corresponding increase in secretion of chenodeoxycholic acid and hyodeoxycholic‐ursodeoxycholic acid. However, the magnitude of the change in secretion of these bile acids could not account for the increased output of phospholipid in bile.
Characterization of acylmono‐, mono‐, di‐, tri‐ and tetraglycosylsterol and saponin in Adzuki bean (Vigna angularis) seeds
Authors: Kojima Michiyuki , Ohnishi Masao , Ito Seisuke , Fujino Yasuhiko 
Published: November 2006

AbstractFive sterylglycosides (acylmono‐, mono‐, di tri‐ and tetraglycosylsterol) and a saponin were isolated from Adzuki beans and characterized. In the glycosylsterols, the principal component sterols were sitosterol and stigmasterol; the major sugar component was glucose. The glucose units were shown to be linked by β1,6‐bonds. The three oligoglycosylsterols were shown to be gentiobiosylsterol, gentiotriosylsterol and gentiotetraosylsterol; the latter two are novel sterylglycosides. The saponin was identified as glucopyranosyl‐(β1→2)‐glucopyranurosyl‐(β1→3′)‐soyasapogenol B (Azukisaponin I) which had previously been found in Adzuki beans.
Synthesis and characterization of triacylglycerols containing linoleate and linolenate
Authors: Awl R. A. , Frankel E. N. , Weisleder D. 
Published: November 2006

AbstractTriacylglycerols containing linoleate and linolenate found in vegetable oils were synthesized in gram quantities for oxidation studies. Two acylation methods were examined to convert diacylglycerols or monoacylglycerols to the desired triacylglycerols. Acylations with fatty acid and 1,1′‐dicyclohexylcarbodiimide in the presence of 4‐dimethylaminopyridine were more rapid, gave triacylglycerols of better isomeric purities and generally better overall yields than the acylations with acid chloride in pyridine. The functional and isomeric purity of the synthetic triacylglycerols were investigated by thin‐layer and gas‐liquid chromatography of the methyl esters, by lipase hydrolysis, and by13C NMR. Quantitative13C NMR provided a valuable tool to determine isomeric structures of the unsaturated triacylglycerols and complemented the lipase hydrolysis method. The triacylglycerols purified by dry column chromatography were obtained in the following respective percent yields, functional and isomeric purities: LLLn, 92.1, 99.4, 98.1; LLnLn, 91.7, 99.2, 97.4; LLnL, 84.2, 99.7, 98.9; and LnLLn 77.5, 97.8, 99.0 (where L=linoleoyl and Ln=linolenoyl glycerol residues). These synthetic triacylglycerols are valuable models to elucidate the interrelationship of unsaturated fatty acids on the oxidative stability of polyunraturated vegetable oils.
Effects of dietary fats on fatty acid composition and Δ5 desaturase in normal and diabetic rats
Authors: Dang A. Q. , Kemp K. , Faas F. H. , Carter W. J. 
Published: November 2006

AbstractWe have studied the effect of various diets on the phospholipid fatty acid composition andin vitro Δ5 desaturase activity of hepatic microsomes derived either from the normal or streptozotocin‐induced diabetic rat. The diets studied were the standard rat chow diet and a basal fat‐free diet supplemented either with 20 percent saturated fat, 20 percent unsaturated fat, or 20 percent menhaden oil. Phospholipid fatty acid composition analysis revealed that the normal rat fed the saturated fat or menhaden oil diet had significantly decreased arachidonate levels, consistent with decreased Δ5 desaturase activities and decreased 18∶2n−6 intake. On the contrary, the unsaturated fat diet decreased dihomo‐γ‐linolenate and increased arachidonate levels, without increased Δ5 desaturase activity. Streptozotocininduced diabetes resulted in decreased arachidonate and Δ5 desaturase activity. The unsaturated fat diet fed to the diabetic rat also failed to correct this decreased Δ5 desaturase activity. The unsaturated fatty acids in this diet also displaced a substantial amount of n−3 fatty acids in both normal and diabetic microsomes, due to the competition between these two fatty acid families for incorporation into the membrane phospholipids. Conversely, the menhaden oil diet fed to the normal and diabetic rats displaced n−6 fatty acids, reduced Δ5 desaturase activity, and enhanced 22∶6n−3 incorporation into diabetic microsomes.
Turnover of fatty acyl‐CoA oxidase in the liver of rats fed on a partially hydrogenated marine oil
Authors: Horie Shuchi , Suga Tetsuya 
Published: November 2006

AbstractThe change in turnover of fatty acyl‐CoA oxidase (FAO), the rate‐limiting enzyme of the peroxisomal β‐oxidation system, was investigated in rats fed a 30% (w/w) partially hydrogenated marine oil (PHMO) diet. The FAO activity increased five‐fold after two weeks of PHMO feeding, and decreased after withdrawal of the diet. Based onin vivo experiments using L‐[4,5‐3H]leucine and an immunoprecipitation technique, the increase in the activity of FAO could be accounted for by a 1.6‐fold higher rate of FAO synthesis and a 3.4‐fold slower rate of FAO degradation as compared to controls. In the same PHMO‐fed rats, the rates of synthesis and degradation of carnitine palmitoyltransferase were 1.8‐fold higher and 2.0‐fold slower, respectively, as compared to controls. The results indicate that the observed increase in the activity of the enzymes of peroxisomal β‐oxidation is mainly due to a reduced rate of FAO degradation in the liver of rats fed the PHMO diet.
Linoleic acid hydroperoxide concentration in relation to mutagenicity of repeatedly used deep‐frying fats
Authors: Hageman G. , Kikken R. , ten Hoor F. , Kleinjans J. 
Published: November 2006

AbstractA high‐performance liquid chromatography procedure was developed to measure linoleic acid hydroperoxides (LAHPO) in 19 used, deep‐frying fat samples that were screened for mutagenicity. The detection limit of the method was found to be 10 nmol of LAHPO/g of fat. In eight samples, LAHPO were not detected; levels in the other samples ranged from 17 to 267 nmol/g of fat. LAHPO were not detectable in unusued hydrogenated frying fat samples. Concentrations of LAHPO correlated positively with mutagenicity to Salmonella tester strains TA97 and TA100, in presence of S9 mix only; coefficients of correlation were, respectively, r=0.48 (p<0.05) and r=0.24 (n.s.). Without metabolic activation no significant associations were observed. These results suggest that metabolites or secondary autoxidation products of linoleic acid generated in presence of liver S9 mix may contribute to mutagenicity of some of the used deep‐frying fat samples.
Fatty acid synthesis from [2‐14C]acetate in normal and peroxisome‐deficient (Zellweger) fibroblasts
Authors: Poulos A. , Usher S. , Paton B. C. 
Published: November 2006

AbstractThe incorporation of [2‐14C]acetate into the lipids of normal and peroxisome‐deficient (Zellweger's syndrome) skin fibroblasts was examined. Most of the label was incorporated into triacyglycerol fatty acids in normal as well as Zellweger's syndrome cells. Triacylglycerols and cholesteryl esters in Zellweger's syndrome cells contained increased levels of labelled saturated and monounsaturated very long‐chain fatty acids (VLCFA, that is fatty acids with more than 22 carbon atoms), in particular hexacosanoic (26∶0) and hexacosaenoic (26∶1) acids. As traces of labelled VLCFA with up to 32 carbon atoms were detected in triacylglycerols even in control cells it is probable that these fatty acids are formed naturally during the elongation process. Our data suggest that peroxisomes are involved in the chain shortening of the saturated and monounsaturated VLCFA.
Docosahexaenoic acid increases permeability of lipid vesicles and tumor cells
Authors: Stillwell William , Ehringer William , Jenski Laura J. 
Published: November 2006

AbstractDocosahexaenoic acid (DHA), a long‐chain polyunsaturated ω3 fatty acid, is tested to determine its mode of action as an anti‐cancer agent. We demonstrate that DHA can increase the permeability of phospholipid vesicles, as monitored by vesicle swelling in isomolar erythritol and leakage of sequestered carboxylfluorescein, and T27A tumor cells, as monitored by swelling in isomolar erythritol and release of sequestered51Cr. DHA was incorporated into lipid vesicles as either the free fatty acid or as 1‐stearoyl‐2‐docosahexaenoyl‐sn‐glycero‐3‐phosphocholine. DHA was incorporated into the tumor cells by fusion with vesicles made from the mixed‐chain phosphatidylcholines. DHA is demonstrated here to be much more effective in increasing permeability than is oleic acid, the major unsaturated fatty acid normally found in tumor plasma membranes. It is proposed that incorporation of DHA makes tumor plasma membranes substantially more permeable, which may explain, in part, its anti‐tumor properties.
Reduction of fatty acid hydroperoxides by human parotid saliva
Authors: Terao Junji , Nagao Akihiko , Yuki Hiroko , Itoh Yoshio 
Published: November 2006

AbstractArachidonic acid hydroperoxide (15‐hydroperoxyeicosatetraenoic acid; 15‐HPETE) was introduced into human parotid saliva and incubated at 37°C. Straight phase high‐performance liquid chromatography analysis of the reaction mixture showed that 15‐HPETE was detoxified to its reduced form, 15‐hydroxyeicosatetraenoic acid, in the presence of glutathione. Therefore, it is concluded that human parotid saliva possesses fatty acid hydroperoxide‐reducing ability. However, its effectiveness was found to be lower than that of blood plasma.
The identification of the allylic nitrite and nitro derivatives of methyl linoleate and methyl linolenate by negative chemical ionization mass spectroscopy
Authors: Gallon Aris A. , Pryor William A. 
Published: November 2006

AbstractThe autoxidation of polyunsaturated fatty acids is initiated bothin vivo andin vitro by nitrogen dioxide. The mechanism of the initiation process is believed to involve both addition reactions and hydrogen atom abstraction reactions, with hydrogen abstraction predominating at low levels of nitrogen dioxide. Therefore low levels of nitrogen dioxide should react with polyunsaturated fatty acids to give allylic derivatives; in an anaerobic system these derivations should be allylic nitro and nitrite compounds. Using negative methane chemical ionization mass spectrometry and other analytical techniques, we have identified these allylic nitrite and nitro compounds from the reactions of low levels of nitrogen dioxide with methyl linoleate and methyl linolenate in the absence of oxygen.
The effect of incubation temperature on yolk lipid parameters during embryonic development of the alligator (Alligator mississippiensis)
Authors: Noble R. C. , Deeming D. C. , Ferguson M. W. J. , McCartney R. 
Published: November 2006

AbstractThe effect of incubation temperature (30 and 33°C) on yolk lipid uptake and changes in the alligator has been studied. Notable changes occurred in the lipid and fatty acid compositions of the yolk. Triacylglycerols and phospholipids were the major lipid components of the yolk at the start of incubation. However, during incubation the level of cholesteryl esters increased considerably to become a major lipid component of the yolk at hatching. This increase in cholesteryl ester level occurred at a much earlier time in the eggs incubated at 33°C. The cholesteryl esters which accumulated within the yolk showed much higher levels of oleic acid. The triacylglycerols and phospholipids of the yolk both contained unusually high levels of palmitoleic acid. Their fatty acid compositions remained relatively unchanged during incubation. The lipid composition of the liver toward the end of the incubation period reflected the changes that occurred within the yolk. Thus the percentage of cholesteryl esters in the liver lipid of embryos incubated at 30 and 33°C were 7 and 40%, respectively. The accumulated cholesteryl esters also showed a significantly higher content of oleic acid. The differences in the yolk and tissue lipids during incubation at the two temperatures are discussed with reference to the respective rates of embryonic development but in particular with respect to the feature of temperature‐dependent sex determination.
Regiospecific analysis of triacylglycerols using allyl magnesium bromide
Authors: Becker Claus C. , Rosenquist Annemette , Hølmer Gunhild 
Published: November 2006

AbstractA method for the regiospecific analysis of triacylglycerols (TAG), using the Grignard reagent allyl magnesium bromide (AMB) to partially deacylate TAG, is described. 1,3‐Distearoyl‐2‐oleoyl‐glycerol (SOS) and 1,3‐didecanoyl‐2‐palmitoyl‐glycerol (CPC) were reacted with AMB. From the resulting mixture, the four different classes of partial acylglycerols and TAG were isolated, and the mole ratios between stearic acid and oleic acid, or decanoic acid and palmitic acid, respectively, were determined in each fraction. Different approaches of calculating the composition of the fatty acids in positionssn‐1(3) andsn‐2 of the original TAG were compared. For thesn‐2 position, the best estimate was the direct determination of the fatty acid composition of 2‐monoacylglycerol (MAG). Mole percentages of stearic acid and decanoic acid in thesn‐1(sn‐3) positions of SOS and CPC, respectively, were most accurately estimated from the fatty acid compositions of TAG and 2‐MAG according to the formula: 1.5×TAG−0.5×2‐MAG. Using AMB and the present method of calculation, the results obtained were more accurate and showed smaller standard derivations than those obtained using other common deacylating agents, such as ethyl magnesium bromide or pancreatic lipase.
Synthesis of trisubstituted C18 pyrrole fatty ester derivatives
Authors: Lie Ken Jie Marcel S. F. , Wong K. P. 
Published: November 2006

AbstractReaction of methyl 10(11)‐dicarbethoxymethyl‐9,12‐dioxooctadecanoate (1a,1b) with ammonium acetate furnished a mixture of positional isomers of a pyrrole derivative, methyl 9,12‐imino‐10(11)‐dicarbethoxymethyl‐9,11‐octadecadienoate (2a,2b). Decarboxylation of the mixture of compounds 2a,2b with sodium carbonate in aqueous methanol yielded a mixture of compounds 3a,3b containing a CH2COOCH3 group at the 3‐ or 4‐position of the pyrrole ring after esterification. Heating of the hydrolyzed mixture of compounds 3a,3b at 180°C for 1 h gave the desired trisubstituted pyrrole derivatives, methyl 9,12‐imino‐10(11)‐methyl‐9,11‐octadecadienoate (4a,4b), containing a methyl group at the 3‐ or 4‐position of the pyrrole nucleus. The structures of the products and intermediates were confirmed by infrared, and by1H and13C nuclear magnetic resonance spectroscopy.
The Effects of dietary n−3/n−6 ratio on brain development in the mouse: a dose response study with long‐chain n−3 fatty acids
Authors: Wainwright P. E. , Huang Y. S. , Bulman‐Fleming B. , Dalby D. , Mills D. E. , Redden P. , McCutcheon D. 
Published: November 2006

AbstractThis study examines the effects of the ratio of n−3/n−6 fatty acids (FA) on brain development in mice when longchain n−3 FA are supplied in the diet. From conception until 12 days after birth, B6D2F1 mice were fed liquid diets, each providing 10% of energy from olive oil, and a further 10% from different combinations of free FA concentrates derived from safflower oil (18∶2n−6), and fish oil (20∶5n−3 and 22∶6n−3). The range of dietary n−3/n−6 ratios was 0,025, 0.5, 1.0, 2.0, and 4.0, with an n−6 content of greater than 1.5% of energy in all diets, and similar levels of total polyunsaturated fatty acids (PUFA). In an additional group of ratio 0.5, 18∶2n−6 was partially replaced by its δ6 desaturation product, 18∶3n−6. Biochemical analyses were conducted on 12‐day‐old pup brains, as well as on samples of maternal milk. No obvious effects on overall pup growth and development were observed, apart from a smaller litter size at ratio 1. Co‐variance analysis indicated that increasing the n−3/n−6 ratio was associated with slightly smaller brains, relative to body weight. We found that 18∶2n−6 and 20∶5n−3 were the predominant n−6 and n−3 FA in the milk; in the brain these were 20∶4n−6 and 22∶6n−3, respectively. Increasing dietary n−3/n−6 ratios generally resulted in an increase in n−3 FA, with a corresponding decrease in n−6 FA. The n−3/n−6 ratio of the milk lipids showed a strong linear relationship with the diet, but in the brain the rate of increase tended to decrease beyond 0.5 (phosphatidylcholine, PC) and 0.25 (phosphatidylethanolamine, PE), such that there was a significant quadratic contribution to the relationship. The partial replacement of dietary 18∶2n−6 with 18∶3n−6 raised levels of 20∶4n−6 in milk, brain PC, and brain PE. These results indicate that the n−3/n−6 ratio of the phospholipids in the developing mouse brain responds maximally to maternal dietary long‐chain n−3/n−6 ratios of between 0.25 and 0.5.
Effect of maternal dietary fats with variable n−3/n−6 ratios on tissue fatty acid composition in suckling mice
Authors: Huang Y. ‐S. , Wainwright P. E. , Redden P. R. , Mills D. E. , Bulman‐Fleming B. , Horrobin D. F. 
Published: November 2006

AbstractThis report examines the distribution of n−3 and n−6 fatty acids in heart, kidney and liver phosphatidylcholine and phosphatidylethanolamine of suckling mice from dams fed a fat‐supplemented diet with variable n−3/n−6 ratios. After conception and throughout the pregnancy and lactation period, dams were fed a fat‐free liquid diet supplemented with 20% by energy of oil mixtures (fish oil concentrate, rich in 20∶5n−3 and 22∶6n−3, and safflower oil concentrate, rich in 18∶2n−6). The diets contained similar amounts of combined n−3 and n−6 fatty acids but variable ratios of n−3 to n−6 fatty acids (0,025, 0.5, 1, 2, and 4). In 12‐day‐old suckling mice, as the n−3nn−6 ratio in the maternal diet increased (up to approx. 0.5), the tissue levels of 20∶5n−3, 22∶5n−3 and 22∶6n−3 increased, whereas those of 18∶2n−6 and 20∶4n−6 decreased. The responses were similar in both phospholipid subclasses, but varied between different tissues. Generally, the n−3/n−6 ratios were significantly greater in pup tissues than in milk fat, indicating preferential incorporation of n−3 over n−6 fatty acids into phospholipids during growth. However, the incorporation of n−3 fatty acids in pups was significantly suppressed whereas that of n−6 fatty acids was increased when 18∶2n−6 was replaced by its δ6‐desaturation product, 18∶3n−6 (concentrated from evening primrose oil), as the source on n−6 fatty acid. This result suggests that δ6 desaturase activity in neonate tissues is low, and consequently, the metabolism of 18∶2n−6 to longer chain n−6 fatty acids is reduced. The preformed long‐chain n−3 fatty acids, which bypass δ6‐desaturation, were thus, preferentially incorporated into tissue phospholipids.
Anorexic contribution to increased linoleate mobilization and oxidation in lymphoma‐bearing mice
Authors: Kannan Ram , Gan‐Elepano Minerva , Baker Nome 
Published: November 2006

AbstractTo test for a regulatory defect in adipose triacylglycerol (essential) fatty acid mobilization in lymphoma‐bearing mice, free [1‐14C]linoleic acid/mouse serum albumin was injectediv into lymphoma‐bearing and control mice, adapted to a reversed light cycle, and studied in three dietary states in the dark period. Mean daily food intake decreased in mice with small and large tumor burdens. Plasma free fatty acid (FFA) oxidation rates, which approximate FFA mobilization rates, were estimated by multicompartmental analysis (CONSAM). Oxidation of linoleate to CO2 was reduced significantly (85%) inad libitum fed as compared to briefly fasted control mice but not in fedvs. fasted mice with large or small tumor burdens. However, plasma FFA oxidation rates to CO2 did not differ in briefly fasted tumor‐bearing and pairfed control mice. When re‐fed a 250‐mg test meal, briefly fasted mice with small tumors suppressed plasma free linoleic acid oxidation, as did controls. During simulated night, mildly anorexic, tumor‐bearing mice with small tumor burdens mobilized essential fatty acids much faster than controls. This could explain body fat loss. The abnormally rapid rates of FFA (free linoleic acid) mobilization at night probably result from anorexia rather than from inability of food to suppress fat mobilization.
Urinary response toin vivo lipid peroxidation induced by vitamin E deficiency
Authors: Lee Hye‐Sung , Shoeman D. W. , Csallany A. Saari 
Published: November 2006

AbstractExperiments were carried out to measure the urinary excretion of free and conjugated malonaldehyde (MDA) and other thiobarbituric acid reactive substances (TBARS) in vitamin E deficient and vitamin E supplemented rats. From both dietary groups, six TBA positive fractions were isolated, in addition to that containing free MDA, by high‐performance liquid chromatography (HPLC) on a TSK‐GEL G‐1000PW column. Three of the fractions isolated were found to be significantly increased in vitamin E deficiency. After acid hydrolysis, only one of the above compounds produced free MDA which indicated the presence of derivatized MDA. Only this fraction exhibited fluorescence at excitation 370 nm and emission 450 nm. The five other fractions formed 2,4‐dinitrophenylhydrazones (2,4‐DNPH), indicating the presence of carbonyl groups, but the derivatized MDA fraction did not. No significant differences were found in free MDA levels between the vitamin E deficient and the vitamin E supplemented groups.