bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatty acid allene oxides. III. Albumin‐induced cyclization of 12,13(S)‐epoxy‐9(Z),11‐octadecadienoic acid
Authors: Hamberg Mats , Hughes Molly A. 
Published: November 2006

AbstractRecently, corn (Zea mays L.) hydroperoxide dehydrase was found to catalyze the conversion of 13(S)‐hydroperoxy‐9(Z),11(E)‐octadecadienoic acid into an unstable fatty acid allene oxide, 12,13(S)‐epoxy‐9(Z),11‐octadecadienoic acid. This study is concerned with the chemistry of 12,13(S)‐epoxy‐9(Z),11‐octadecadienoic acid in the presence of vertebrate serum albumins.Albumins were found to greatly enhance the aqueous half‐life of the allene oxide, i.e. 14.1±1.8 min, 11.6±1.2 min and 4.8±0.5 min at 0 C in the presence of 15 mg/ml of bovine, human and equine serum albumins, respectively, as compared with ca. 33 sec in the absence of albumin. Degradation of allene oxide in the presence of bovine serum albumin led to the formation of a novel cyclization product, i.e. 3‐oxo‐2‐pentyl‐cyclopent‐4‐en‐1‐octanoic acid (12‐oxo‐10‐phytoenoic acid, in which the relative configuration of the side chains attached to the five‐membered ring istrans). Steric analysis of the cyclic derivative showed that the compound was largely racemic (ratio between enantiomers, 58∶42).12‐Oxo‐10,15(Z)‐phytodienoic acid, needed for reference purposes, was prepared by incubation of 13(S)‐hydroperoxy‐9(Z),11(E),15(Z)‐octadecatrienoic acid with corn hydroperoxide dehydrase. Steric analysis showed that the 12‐oxo‐10,15(Z)‐phytodienoic acid thus obtained was not optically pure but a mixture of enantiomers in a ratio of 82∶18.
Composition of mixed octadecadienoates via ozonolysis, chromatography and computer solution of linear equations
Authors: Dutton H. J. , Johnson S. B. , Pusch F. J. , Lie Ken Jie M. S. F. , Gunstone F. D. , Holman R. T. 
Published: November 2006

AbstractAn approach to the analysis of 55 possible nonconjugated positional isomers of octadecadienoic acid is described and tested with mixtures of individual synthetic methyl esters. In the first example, by ozonolysis a sevencomponent mixture consisting ofcis,cis 5,12‐, 6,10‐, 6,11‐, 6,12‐, 7,12‐, 8,12‐, and 9,12‐octadecadienoates was converted to aldehydes, aldehyde‐esters and dialdehydes. These fragments were separated on a 50 m×0.2 mm free fatty acid phase (FFAP) vitreous silica capillary column. Equations for an arbitrarily restricted 12×15 matrix of linear simultaneous equations and a computer solution of the matrix provided the composition of the initial methyl octadecadienoate mixture. The power and significance of this method became apparent with the observation that only two of the seven isomers in the known mixture were resolved as single peaks by state‐of‐the‐art capillary gas chromatography, but all seven were identified and estimated with acceptable error by the ozonolysis‐capillary gas chromatography‐computer procedure. In a generalized approach to the analysis of the 55 possible nonconjugated isomers, a computer program selects the appropriate matrix of linear simultaneous equations based on the aldehyde data supplied by the analyst. Twenty of 21 combinations of seven isomeric esters taken five at a time have been analyzed to assess the efficiency of the method. To illustrate applicability at this stage of development, the method has been used to analyze the diene products of the hydrazine reduction of γ‐linolenic acid and the diene products from the biological desaturation of isomeric monoenes. The possibility of distinguishing geometric and positional isomers of 18∶2 has been opened by the observed separation ofcis‐andtrans‐unsaturated aldehydes and aldehyde‐esters.
Mammary lipoprotein lipase in plasma of cows after parturition or prolactin infusion
Authors: Liesman James S. , Emery Roy S. , Akers R. Michael , Tucker H. Allen 
Published: November 2006

AbstractPlasma lipase activity from the mammary vein and a tail blood vessel was measured in periparturient Holstein cows treated in one of three ways: control, CB154 (2‐Br‐α‐ergocryptin) or CB154 plus prolactin. CB154 administration decreased basal serum prolactin concentration by 80% and blocked the normal parturient increase of serum prolactin. In CB154 plus prolactin‐treated cows, prolactin was infused continously for six days starting five and eight days prepartum. Plasma lipase activity was not detectable up to 26 hr prepartum in control and CB154‐treated cows or before the start of prolactin infusion in CB154 plus prolactin‐treated cows. After two hr prepartum, plasma lipase activity was detected in all treatments. In CB154 plus prolactin‐treated cows, plasma lipase activity was detected in the presence of high concentrations of serum progesterone four days after the start of prolactin infusion and at least two days before parturition. Plasma lipase activity was four times greater in the mammary vein than in the tail vessel at sampling times at which activity was detected in both vessels. We propose the difference between plasma lipase activity from the mammary vein and tail vessel is due to release of lipoprotein lipase from the mammary gland into blood, and this activity can be induced prepartum by prolactin or at parturition even if the parturient increase in prolactin is suppressed.
Use of a fluorescent radiolabeled triacylglycerol as a substrate for lipoprotein lipase and hepatic triglyceride lipase
Authors: Dousset Nicole , Negre Anne , Salvayre Robert , Rogalle Pierre , Dang Quoc Quan , Douste‐Blazy Louis 
Published: November 2006

AbstractA fluorescent radiolabeled triacylglycerol has been synthesized by using a fluorescent fatty acid (pyrene decanoic acid) and a radiolabeled oleic acid. This analog of the natural substrate, 1(3)pyrene decanoic‐2,3(1,2)‐dioleoyl‐sn‐glycerol, has been tested as substrate for determining lipoprotein lipase and hepatic triacylglycerol lipase activities in post‐heparin plasma. Optimal conditions for the determination of the two post‐heparin plasma lipases were similar to those using radiolabeled triolein. Using this substrate, both post‐heparin lipases exhibited their characteristic properties (pH optimum and effect of inhibitors) and attacked external ester bonds (1 or 3) containing pyrene decanoic and oleic acids at a similar rate
Diet‐induced type IV‐like hyperlipidemia and increased body weight are associated with cholesterol gallstones in hamsters
Authors: Hayes K. C. , Khosla Pramod , Pronczuk Andrzej 
Published: November 2006

AbstractMale Syrian hamsters (60–70 g) were fed purified diets containing 5% fat (American Fat Blend) and 15% fiber with or without 0.3% cholesterol (0.86 mg/kcal), for 12 weeks. Hamsters fed the cholesterol‐supplemented challenge diet revealed a major increase in plasma triglyceride between 9 and 12 weeks, whereas plasma cholesterol (which reflected body weight dynamics) increased three‐fold up to nine weeks and plateaued (342±22vs. 122±5 mg/dL). The greatest increases in cholesterol occurred in the very low density lipoprotein (VLDL) and high density lipoprotein (HDL2) fractions. Gallstone incidence was similar (69%vs. 78%) for cholesterol‐supplementedvs. control hamsters, but the type of stones differed. Of the cholesterol‐supplemented hamsters with gallstones, 45% had cholesterol stones and 55% had pigment stones. Only pigment stones were seen in control hamsters. Hamsters with cholesterol stones were 25% heavier and transported most cholesterol in VLDL (33±5%), approximately double that in VLDL of cholesterol‐supplemented hamsters with no stones (19±3%) or cholesterol‐supplemented hamsters with pigment stones (21±3%). Hamsters with pigment stones or no stones (regardless of diet fed) transported the majority of their cholesterol in HDL2 (44%), whereas this figure was only 27% in hamsters that developed cholesterol stones. Thus pigment stones develop routinely in hamsters fed casein‐based purified diets. Adding dietary cholesterol resulted in cholesterol gallstones only in those hamsters that gained the most weight and whose terminal VLDL/HDL cholesterol ratio exceeded 1.0, not unlike the lipoprotein profile of obese humans who develop cholesterol gallstones.
Lipids containing isoricinoleoyl (9‐hydroxy‐cis‐12‐octadecenoyl) moieties in seeds ofWrightia species
Authors: Ahmad Fasih , Schiller Helmut , Mukherjee Kumar D. 
Published: November 2006

AbstractComposition of lipids in mature seeds ofWrightia tinctoria andWrightia coccinea, which contain large proportions of isoricinoleic acid (9‐hydroxy‐cis‐12‐octadecenoic acid) as constituent fatty acid beside the common long chain fatty acids, is reported. The major classes of acyl lipids in the seeds of the twoWrightia species, identified by chromatographic and mass spectrometric analyses, are found to be triisoricinoleoylglycerol and diisoricinoleoylacylglycerols. Phospholipids and glycolipids contain only small proportions of isoricinoleoyl moieties. Among two possible precursors for the biosynthesis of isoricinoleic acid, 9‐hydroxystearic acid, but notcis‐12‐octadecenoic acid, is detectable in the seed lipids.
(24R‐14α‐methyl‐24‐ethyl‐5α‐cholest‐9(11)‐en‐3β‐ol: A new 14α‐methylsterol fromCucumis sativus
Authors: Akihisa Toshihiro , Shimizu Naoto , Tamura Toshitake , Matsumoto Taro 
Published: November 2006

AbstractThe structure of a new 14α‐methylsterol isolated fromCucumis sativus has been shown to be (24R)‐14α‐methyl‐24‐ethyl‐5α‐cholest‐9(11)‐en‐3β‐ol. Characterization of the 14α‐methyl‐Δ9(11) skeletal structure was undertaken based on the comparison with 14α,24‐dimethyl‐5α‐cholest‐9(11)‐en‐3β‐ol obtained from 24‐methylpollinastanol by acid‐catalyzed isomerization. Isolation and identification of an additional 14α‐methylsterol, 24‐methylene‐pollinastanol, from the plant also is described.
cis‐9,10‐Epoxystearic acid in human leukocytes: Isolation and quantitative determination
Authors: Fahistadius Per 
Published: November 2006

AbstractRacemiccis‐9,10‐epoxystearic acid was isolated from total lipids of human leukocytes. Identification of the epoxy acid was based mainly on gas liquid chromatographicmass spectrometric analysis and on its chemical conversion intothreo‐9,10‐dihydroxystearic acid. A mass spectrometric method for quantitative determination ofcis‐9,10‐epoxystearic acid using the tetradeuterated compound as internal standard was developed. Using this method, nonstimulated human leukocytes were found to contain 5.1±2.2 μg (SD) ofcis‐9,10‐epoxystearic acid per 109 cells (n=8). More than 90% of the epoxy acid occurred in its esterified form in leukocyte lipids.
Regulation of the metabolism of linoleic acid to arachidonic acid in rat hepatocytes
Authors: Voss Anne C. , Sprecher Howard 
Published: November 2006

AbstractWhen 5×106 hepatocytes were incubated for 40 min with from 0.15 to 0.60 mM [1‐14C]linoleic acid, [1‐14C]6,9,12‐octadecatrienoic acid, or [1‐14C]8,11,14‐eicosatrienoic acid, there was a concentration‐dependent acylation of radioactive metabolites into both triglycerides and phospholipids. When the concentration of either [1‐14C]linoleic acid or [1‐14C]8,11,14‐eicosatrienoic acid exceeded 0.3 mM, there was no further increase in the metabolism of either fatty acid to other (n−6) metabolites. When the concentration of [1‐14C]6,9,12‐octadecatrienoic acid exceeded 0.15 mM, there was an apparent substrate‐induced inhibition in its metabolism to 8,11,14‐eicosatrienoic acid. With all three substrates (0.3 mM), there was time‐dependent metabolism to other (n−6) acids. Cells then were incubated simultaneously with 0.3 mM [1‐14C]linoleic acid along with 0.15 to 0.45 mM 6,9,12‐octadecatrienoic acid or 8,11,14‐eicosatrienoic acid. These exogenous nonradioactive (n−6) acids suppressed but did not abolish the conversion of [1‐14C]linoleate to radioactive arachidonate. These findings suggest that some linoleate is converted to arachidonate without intracellular mixing of 6,8,12‐octadecatrienoic or 8,11,14‐eicosatrienoic acids. This hypothesis is supported by the finding that exogenous linoleate did not markedly affect the metabolism of [1‐14C]6,9,12‐octadecatrienoic or [1‐14C]8,11,14‐eicosatrienoic acid by microsomal chain elongating or desaturating enzymes.
Two unsaturated 9R‐hydroxy fatty acids from the cyanobacteriumAnabaena flos‐aquae f. flos‐aquae
Authors: Murakami Nobutoshi , Shirahashi Hideaki , Nagatsu Akito , Sakakibara Jinsaku 
Published: November 2006

Abstract(9R‐10E,12Z,15Z)‐9‐Hydroxyotadecatrienoic acid and (9R,10E,12Z)‐9‐hydroxyoctadecadienoic acid were isolated from the nitrogen fixing cyanobacteriumAnabaena flosaquae. f. flos‐aquae and characterized as the corresponding methyl esters. This is the first report of the natural occurrence of 9R‐oxygenated fatty acids.
Effect of phosphatidylcholine structure on the adenylate cyclase activity of a murine fibroblast cell line
Authors: Calorini Lido , Mugnai Gabriele , Mannini Antonella , Ruggieri Salvatore 
Published: November 2006

AbstractTo determine which structural characteristics of membrane phospholipids influence adenylate cyclase activity, we measured basal and sodium fluoride‐ or forskolin‐stimulated activity in a murine fibroblast cell line,i.e., Balb/c3T3 cells grown in media supplemented with fetal calf serum (FCS), lipid‐depleted FCS (LD‐FCS) or LD‐FCS complexed with different phosphatidylcholine (PC) molecular species. Cells grown in the presence of LD‐FCS showed a substantial decrease in their basal and NaF‐stimulated adenylate cyclase activities; however, their forskolin‐stimulated activity was not altered, suggesting that the enzyme's catalytic site is not affected by changes in membrane lipids. Media supplemented with different LD‐FCS/PC complexes were shown to prevent the LD‐FCS‐mediated reduction of basal and NaF‐stimulated adenylate cyclase activity to different extents. Addition ofcis‐9‐16∶1/cis‐9‐16∶1,cis‐9‐18∶1/cis‐9‐18∶1 orcis‐9‐18∶1/cis‐9,12‐18∶2sn‐glycerophosphocholine (GPC) completely restored adenylate cyclase activity, whilecis‐11‐18∶1/cis‐11‐18∶1 GPC was not effective and only a partial recovery was observed with 16∶0/16∶0, 16∶0/cis‐9‐18∶1 andtrans‐9‐18∶1 GPC. Considering the structural features of these seven PC molecular species, the findings suggest that an optimal lipid environment is conferred to the enzyme by the presence of thecis double bonds, each located in Δ9 position of the PC acyl chains. The limited effect ofcis‐9‐16∶1/cis‐9‐18∶1 GPC andcis‐9‐18∶1/cis‐9‐16∶1 GPC suggests that an equal length of the terminal hydrocarbon chains extending bevond the Δ9 double bonds is also important. Moreover, complete restoration of adenylate cyclase activity in cells exposed to 16∶0/cis‐9,12‐18∶2 GPC suggests that twocis‐9,12 double bonds located on the same chain are as effective as twocis‐9 double bonds each located on two different chains of PC. As the four double bonds of 16∶0/cis‐5,8,11,14‐20∶4 GPC had no effect, a mere increase in the number of double bonds seems insufficient to build an optimal lipid microenvironment for the enzyme.
Inositol 1,4,5‐trisphosphate accumulation in brain of lithium‐treated rats
Authors: Ishima Yoshio , Fujimagari Michiyo , Masuzawa Yasuo , Waku Keizo 
Published: November 2006

AbstractThe mechanism of action of lithium as a drug for patients with affective disorders was investigated. Three‐week‐old male rats were orally administered 2.7 mEq Li2CO3/kg/d for 1 or 3 wk, and phosphatidylinositol (PI), phosphatidylinositol 4‐phosphate (PIP), phosphatidylinositol 4,5‐bisphosphate (PIP2), inositol phosphate (IP), inositol diphosphate (IP2) and inositol triphosphate (IP3) levels in brain were measured. The levels of IP were increased 1.7 and 2.4 times after 1 wk and 3 wk of lithium administration, respectively, while PI, PIP, PIP2, IP2 and IP3 levels were not altered. IP3 was further fractionated by high‐performance liquid chromatography into I‐1,3,4‐P3 and I‐1,4,5‐P3. In the control rat brain, the relative percentages of I‐1,3,4‐P3 and I‐1,4,5‐P3 were 95.8 and 4.2, respectively. However, after 3 wk of lithium administration, the values were changed to 69.6 and 30.3%, respectively. This increase in the neurotransducer I‐1,4,5‐P3 in the brain may be relevant to the mechanism of action in the lithium treatment of patients with manic‐depressive disorders.
Multiple inhibitory effects of garlic extracts on cholesterol biosynthesis in hepatocytes
Authors: Gebhardt Rolf 
Published: November 2006

AbstractExposure of primary rat hepatocytes and human HepG2 cells to water‐soluble garlic extracts resulted in the concentration‐dependent inhibition of cholesterol biosynthesis at several different enzymatic steps. At low concentrations, sterol biosynthesis from [14C]acetate was decreased in rat hepatocytes by 23% with an IC50 (half‐maximal inhibition) value of 90μg/mL and in HepG2 cells by 28% with an IC50 value of 35 μg/mL. This inhibition was exerted at the level of hydroxymethylglutaryl‐COA reductase (MHG‐CoA reductase) as indicated by direct enzymatic measurements and the absence of inhibition if [14C]mevalonate was used as a precursor. At high concentrations (above 0.5 mg/mL), inhibition of cholesterol biosynthesis was not only seen at an early step where it increased considerably with dose, but also at later steps resulting in the accumulation of the precursors lanosterol and 7‐dehydrocholesterol. No desmosterol was formed which, however, was a major precursor accumulating in the presence of triparanol. Thus, the accumulation of sterol precursors seem to be of less therapeutic significance during consumption of garlic, because it requires concentrations one or two orders of magnitude above those affecting HMG‐CoA reductase. Alliin, the main sulfur‐containing compound of garlic, was without effect itself. If converted to allicin, it resulted in similar changes of the sterol pattern. This suggested that the latter compound might contribute to the inhibition at the late steps. In contrast, nicotinic acid and particularly adenosine caused moderate inhibition of HMG‐CoA reductase activity and of cholesterol biosynthesis suggesting that these compounds participate, at least in part, in the early inhibition of sterol synthesis by garlic extracts.
Dietary fat composition and age affect synaptosomal and retinal phospholipid fatty acid composition in C57BL/6 mice
Authors: McGee Carl D. , Greenwood Carol E. , Cinader Bernhard 
Published: November 2006

AbstractThe purpose of this study was (i) to determine whether dietary fat‐induced differences in neural and retinal membranes occur when dietary fat treatment is implemented in aged animals and (ii) to characterize the effect of long‐term differences in dietary fat on neural and retinal membrane composition. For the first objective, young (six‐week‐old) and old (95‐week‐old) mice were randomly assigned to beef tallow (TAL) or soybean oil (SBO) diets for eight weeks. For the second objective, young (four‐week‐old) mice consumed either TAL or SBO diets for 99 weeks. Young and old mice challenged with a change in dietary fat for an eight‐week period showed both diet and age effects on neural and retinal phospholipid fatty acid composition (P<0.05). In addition, significant diet by age interactions were evident. In mice that consumed TAL and SBO diets throughout their life, only retinal phosphatidylethanolamine (PE) 18∶2n−6 and neural phosphatidylserine 22∶5n−6, PE 18∶2n−6 and phosphatidylcholine 18∶2n−6 differed between dietary treatments (P<0.05). Neither the unsaturation index nor the n−6/n−3 ratio was affected by diet. Neural and retinal phospholipid fatty acid composition were responsive to changes in dietary fat even when the treatment was implemented beyond developmental or post‐weanling stages. In contrast, when mice consumed TAL or SBO diets throughout their life, fewer differences in phospholipid fatty acid composition were detected, suggesting that the effect of the dietary treatment was mitigated by aging.
Glucocorticoid and mineralocorticoid hormones depress liver Δ5 desaturase activity through different mechanisms
Authors: de Alaniz Maria J. T. , Marra Carlos Alberto 
Published: November 2006

AbstractThe effects of 11‐deoxycorticosterone and aldosterone on liver Δ5 desaturase activity were examined. Both steroid hormones significantly depressed the conversion of [1‐14C] eicosatrienoic acid to arachidonic acid. However, the mechanism of action of each of these hormones was different. The effect of 11‐deoxycorticosterone was mediated by a soluble protein present in the liver cytosolic fraction. The biological activity of this protein, having a molecular weight lower than 25 kDa, was impaired by trypsin digestion. To determine whether the inhibitory protein was induced through glucocorticoid or mineralocorticoid receptor occupancy, cultured Morris minimal deviation hepatoma cells were pre‐treated with the antiglucocorticoid cortexolone or the mineralocorticoid receptor antagonist spironolactone. The results obtained demonstrated that only glucocorticoid receptor structures were involved in the induction of this regulatory protein. The inhibitory response evoked by aldosterone was mediated by a different mechanism. In the case of aldosterone, the inhibitory action affected the microsomal membranes and was not mediated by a soluble protein messenger.
31P NMR of tissue phospholipids: Competition for Mg2+, Ca2+, Na+ and K+ cations
Authors: Merchant Thomas E. , Glonek Thomas 
Published: November 2006

AbstractPhosphatidylcholine (PC), phosphatidylethanolamine (PE), ethanolamine plasmalogen (EPLAS), sphingomyelin (SPH), phosphatidylinositol (PI), phosphatidylserine (PS), cardiolipin (CL), phosphatidylglycerol (PG) and phosphatidic acid (PA) were dispersed together in Cs(ethylenedinitrilo)tetraacetic acid‐scrubbed chloroform/methanol solution, and high resolution31P nuclear magnetic resonance spectra were recorded. In separate titration experiments, Mg2+ and Ca2+ were added to the dispersed phospholipid mixture to determine the relative interaction potentials of each of the phospholipids for each of the added cations. The association of cations with individual phospholipids was indicated by31P chemical‐shift changes, signal broadening, signal quenching or a combination of these. The titrations revealed that CL had the highest, and PA the next highest, interaction potential for Mg2+ cations. In contrast, PS and PA had the highest, and CL the next highest, interaction potential for Ca2+. Considering only interactions with Ca2+ ions, the phospholipids can be divided into three distinct groups: PS and PA (high interaction potential); CL, PI and PG (intermediate interaction potential); and EPLAS, PE, SPH and PC (essentially no interaction potential). The two phospholipids with the least interaction potential for either of the alkaline‐earth cations were PC and SPH. Na+ and K+ ion interactions with PA, CL, PI and PG were unique and resulted in positive chemical‐shift changes relative to the chemical shifts in the presence of Cs+ ions. Relative to both Cs+ and K+ ions, chemical shifts in the presence of Na+ ions were deshielded δ>0.1 ppm in the order PA>CL>PI>PG.
Reaction of dipyridamole with the hydroxyl radical
Authors: Iuliano Luigi , Pratico Domenico , Ghiselli Andrea , Bonavita Maria S. , Violi Francesco 
Published: November 2006

AbstractDipyridamole [2,6‐bis‐diethanolamino‐4,8‐dipiperidinopyrimido‐(5,4‐d) pyrimidine], a well known platelet aggregation inhibitor, shows powerful hydroxyl radical scavenging activity by inhibiting OH‐dependent salicylate and deoxyribose degradation. Steady‐state competition kinetics experiments with deoxyribose were carried out to evaluate the second‐order rateconstant for the reaction between hydroxyl radical and dipyridamole. OH· radicals were generated either by a Fenton‐type reaction or by X‐ray irradiation of water solutions. A second‐order rate constant k(Dipyridamole+OH·) of 1.72±0.11×1010M−1 s−1 and of 1.54±0.15×1010 M−1 s−1 was measured by Fenton chemistry and by radiation chemistry, respectively. Mannitol was used as an internal standard for hydroxyl radicals in steady‐state competition experiments with deoxyribose. A rate constant k(Mannitol+OH·) of 1.58±0.13×109 M−1 s−1 and 1.88±0.14×109 M−1 s−1 was measured in the Fenton model and in the water radiolysis system, respectively. Both these rate constants are in good agreement with the published data obtained by the “deoxyribose assay” and by pulse radiolysis.