bluuebunny/crossref_metadata_2025 huggingface dataset:
Selected ion monitoring gas chromatography/mass spectrometry of 1,2‐diacylglyceroltert‐butyldimethylsilyl ethers derived from glycerophospholipids
Authors: Ohshima Toshiaki , Koizumi Chiaki
Published: November 2006

Selected ion monitoring was used in conjunction with gas chromatography/mass spectrometry to analyzetert‐butyldimethylsilyl ethers (tert‐BDMS) of 1,2‐diacyl‐sn‐glycerols derived from naturally occurring glycerophospholipids, including those ofEscherichia coli, soybean, egg yolks and porcine liver. First, the fatty acid composition of the unknown glycerophospholipid was determined by gasliquid chromatography (GLC) and, based on that, the fatty acids (mostly >0.5 wt%) were selected for monitoring the characteristic fragmentation ions produced from the fatty acid residues of the correspondingtert‐BDMS derivatives of 1,2‐diacyl‐sn‐glycerols. Next, thetert‐BDMS derivatives were separated by GLC on a 65% methylphenylsilicone gum wall‐coated open‐tubular (WCOT) column according to the degree of unsaturation and the chain length of the fatty acid residues, and then directly introduced into the ion source of the mass spectrometer. The selected fragmentation ions, [RCO+74]+ representative of the fatty acid residues, and [M‐57]+ indicative of the molecular weight of the derivatives, were monitored simultaneously. It thus became possible to determine the molecular species of thetert‐BDMS derivatives by measuring a specific combination of two [RCO+74]+ and an [M‐57]+ ion with the same retention time on the selected ion monitoring (SIM) profile. High background noise caused by volatilization of stationary phase at high temperature was largely overcome by selected ion monitoring. However, the fragmentation ion peaks produced fromtert‐BDMS derivatives of highly unsaturated glycerophospholipids showed a distorted SIM profile, which was attributed to interaction between thetert‐BDMS derivatives and the methylphenylsilicone phase of the column. Use of a WCOT column with a more polar liquid phase is therefore recommended for the analysis of highly unsaturated molecular species.
Double‐bond localization in heneicosapentaenoic acid by a gas chromatography/mass spectrometry (GC/MS) method
Authors: Yamamoto Kohei , Shibahara Akira , Nakayama Takao , Kajimoto Goro
Published: November 2006

Double‐bond locations in heneicosapentaenoic acid from eel lipids were determined by a method involving gas chromatography/mass spectrometry (GC/MS). The methyl esters of the pentaenoate fraction were first partially reduced with hydrazine. The resultingcis‐monoenoates were then methylthiolated, and the resultant adducts were analyzed by GC/MS. The key fragmentation ions generated by the cleavage between the methylthio‐substituted carbons were used to ascertain the original double‐bond positions in the native fatty acid esters. Based on mass spectral evidence, the acid was identified as all‐cis‐6,9,12,15,18‐heneicosapentaenoic acid.
Maternally‐supplied fish oil alters piglet immune cell fatty acid profile and eicosanoid production
Authors: Fritsche Kevin L. , Alexander David W. , Cassity Nancy A. , Huang Shu‐Cai
Published: November 2006

This study was designed to examine the incorporation of omega‐3 (n−3) fatty acids into the immune tissues of pigs nursing fish oil‐fed sows and to determine the effect of maternal dietary n−3 consumption onin vitro immune cell eicosanoid production. On day 107 of gestation, 12 sows were randomly allotted to a diet containing either 7% menhaden fish oil (MFO) or lard (LRD). The fatty acid profile of serum, liver, thymus, splenocytes and alveolar macrophages (AM) of 18–21‐day‐old pigs was significantly affected by the fat source provided to the sow. Arachidonic acid (20∶4n−6) content was typically reduced by more than 50% in MFO as compared with LRD pigs. In MFO pigs, eicosapentaenoic acid (20∶5n−3) was the major n−3 polyunsaturated fatty acid, and its levels matched or exceeded those of arachidonic acid. Basal release of prostaglandin E, thromboxane B and leukotriene B by AM was 60–70% lower in MFOvs. LRD pigs. However, when these immune cells were stimulated with calcium ionophore A23187, release of leukotriene B was similar in MFO and LRD pigs. In conclusion, substituting MFO for LRD in a sow's late‐gestation and lactation diet greatly elevated the content of n−3 fatty acids in the nursing pig immune cells and generally reducedin vitro eicosanoid release by pig immune cells.
Metabolic behavior in rats of a nonprotein microemulsion resembling low‐density lipoprotein
Authors: Maranhão Raul C. , Cesar Thais B. , Pedroso‐Mariani Suzana R. , Hirata Mario H. , Mesquita Carlos H.
Published: November 2006

A protein‐free microemulsion (LDE) with a lipid composition resembling that of low‐density lipoprotein (LDL) was used in metabolic studies in rats to compare LDE with the native lipoprotein. LDE labeled with radioactive lipids was injected into the bloodstream of male Wistar rats, and plasma kinetics of the labeled lipids were followed on plasma samples collected at regular intervals for 12 h after injection. The 24‐h LDE uptake by different tissues was also measured in tissue samples excised after the animals had been sacrificed. We found that LDE plasma kinetics were similar to those described for native LDL [fractional clearance rate (FCR) of cholesteryl ester, 0.42±0.11 h−1]. The major site for LDE uptake was the liver, and the tissue distribution of the LDE injected radioactivity was as one would expect for LDL. To test whether LDE was taken up by the specific LDL receptors, the LDE emulsion was injected into rats treated with 17α‐ethinylestradiol, which is known to increase the activity of these receptors; as expected, removal of LDE from the bloodstream increased (FCR=0.90±0.35 h−1). On the other hand, saturation of the receptors that remove remnants by prior infusion of massive amounts of lymph chylomicrons did not change LDE plasma kinetics. These results indicate that LDE is cleared from plasma by B,E receptors and not by the E receptors that remove remnants. Incorporation of free cholesterol into LDE increased LDE plasma clearance. Incubation studies also showed that LDE incorporates a variety of apolipoproteins, including apo E, a ligand for recognition of lipoproteins by specific receptors. Our data suggest that LDE can be a useful tool to test LDL metabolism and B,E receptor function.
Effect of regulating cholesterol biosynthesis on breath isoprene excretion in men
Authors: Stone Bradford G. , Besse Timothy J. , Duane William C. , Dean Evans C. , DeMaster Eugene G.
Published: November 2006

Isoprene is a normal constituent of human breath and may be derived from the cholesterol synthetic pathway. Acute and chronic lovastatin and a cholesterol‐supplemented diet were used to determine whether a mechanistic link exists between isoprene and cholesterol biosynthesisin vivo in humans. The acute effects of lovastatin, a competitive inhibitor of the rate‐limiting step of cholesterol biosynthesis, on breath isoprene excretion was determined by administering a single 20, 40 or 80 mg dose of this drug to five healthy male subjects at 8 p.m. and measuring their breath isoprene levels every 4 h for one 24 h cycle before and after treatment. When compared to the baseline cycle, all three doses of lovastatin significantly reduced breath isoprene levels at 6 and 10 h post‐drug treatment. Chronic lovastatin therapy (40 mg b.i.d. for 6 wk) reduced 6 a.m. breath isoprene levels (time of maximum baseline value) by 27 ± 9% (SEM) and cholesterol synthesis measured in freshly isolated mononuclear leukocytes (ML) by 12 ± 6%. A cholesterol‐supplemented diet (1070 mg, total) ingested for 6 wk reduced breath isoprene excretion and ML sterol synthesis by 16 ± 5 and 19 ± 4%, respectively. The parallel decreases in isoprene excretion and cholesterol synthesis caused by these pharmacologic and dietary means suggest that breath isoprene is derived from the cholesterol synthesis pathway.
Investigations on the cellular uptake of hexadecylphosphocholine
Authors: Fleer Eduard A. M. , Berkovic Dinko , Eibl Hansjoerg , Unger Clemens
Published: November 2006

The uptake of [(9,10)‐3H]hexadecylphosphocholine (HePC) in six tumor cell lines was studied. All cell lines incorporated HePC in similar amounts, with the exception of the epidermoid cancer cell line KB, which took up higher amounts of HePC. The uptake of HePC at 37°C was shown to be time and concentration dependent. At 20°C, uptake was drastically reduced and at 4°C it was blocked completely. Binding of HePC, at 4°C, was not saturable at concentrations between 5 βg/mL (11.8 μM) and 100 μg/mL (235.3 μM), indicating that cell surface binding is not receptor‐mediated. Furthermore, the effects of inhibitors of endocytosis were investigated. We observed a pronounced inhibitory effect by monensin and cytochalasin B. Colchicine was somewhat less effective whereas chloroquine was almost without effect. From these data we conclude that uptake of HePC is most probably mediatedvia a receptor‐independent endocytotic mechanism.
Fish erythrocytes as a tool to study temperature‐induced responses in plasma membranes
Authors: Dey I. , Szegletes T. , Buda Cs. , Nemcsok J. , Farkas T.
Published: November 2006

The dorsal aorta of carp (Cyprinus carpio L.) was cannulated, and the fish were kept in thermostated aquaria at 5°C for 24h. The water temperature was then gradually increased to 25°C at a rate of 0.5°C/h, and then decreased to 5°C at the same rate. Blood was withdrawn at five‐degree intervals to determine the fluidity of erythrocyte plasma membranes uponex vivo incorporation of the fluorescent dye, 3‐[p‐(6‐phenyl‐1,3,5‐hexatrienyl)phenyl] propionic acid. Steady‐state anisotropy (Rss) of the plasma membranes increased and decreased with the increase and decrease in water temperature, respectively. The sterol‐to‐phospholipid ratio remained unchanged throughout the thermal shifts. The fatty acid compositions of the total phospholipids, of phosphatidylcholine and of phosphatidylethanolamine remained virtually unchanged, except for the level of arachidonic acid, which increased in erythrocytes from fish at the higher temperature (25°C). The molecular species compositions of phosphatidylcholines and phosphatidylethanolamines also remained unaffected throughout the thermal shifts. The erythrocyte plasma membranes were more responsive to temperature shiftsin vivo thanin vitro when percent efficacy was compared. Thus, factors other than lipid changes are conceivably involved in the adaptation of erythrocyte plasma membranes to short‐term thermal changes.
Kinetic study of reactions between tocopheroxyl radicals and fatty acids
Authors: Mukai Kazuo , Morimoto Hitoshi , Okauchi Yuji , Nagaoka Shin‐ichi
Published: November 2006

A kinetic study on the prooxidant effect of vitamin E derivatives has been carried out. Rates of hydrogen abstraction from various fatty acids and egg yolk lecithin by tocopheroxyl radicals were determined spectrophotometrically. The rate constants measured in micellar dispersion were compared with those obtained in homogeneous solutions. The effects of structural variations of the vitamin E derivatives on their prooxidant activities were examined. The formation of lecithin reverse micelles in benzene appears to prevent the tocopheroxyl radicals from reacting with the phospholipid fatty acid moieties.
The urinary excretion of thiobarbituric acid reactive substances and malondialdehyde by normal adult males after consuming a diet containing salmon
Authors: Nelson Gary J. , Morris Virginia C. , Schmidt Perla C. , Levander Orville
Published: November 2006

In this study we investigated the output of thiobarbituric acid reactive substances (TBARS) and malondialdehyde (MDA), as thiobarbituric acid (TBA)‐MDA adduct, in the urine from subjects eating a diet in which the only source of n−3 long‐chain, polyunsaturated fatty acids was fresh salmon. Nine healthy men, ages 30–65, were confined in the United States Department of Agriculture Western Human Nutrition Research Center, San Francisco, CA, for 100 d; food intake and exercise levels were controlled. All subjects were placed on a stabilization diet (StD) for 20 d, then six were fed the salmon diet for 40 d. The others remained on the StD. The groups switched diets for the last 40 d. Both diets were isocaloric (16% protein, 54% CHO and 30% fat by energy %). The salmon diet contained 7.5% of calories from n−6 fatty acids (FAs) and 2% from n−3 FAs, primarily eicosapentaenoic acid and docosahexaenoic acid in a 50∶60 ratio, while the StD contained 7.5% from n−6 FAs and <0.3% n−3 FAs (with presumably no significant amounts of C20 or C22 n−3 FAs). Twenty‐four hour urinary output was collected, and 2% 3−d pool samples prepared for analysis of urinary TBARS and the TBA‐MDA adduct. The total urinary output of each individual varied considerably, and on a daily basis the concentration of autoxidation products in an individual's urine varied also. However, the mean daily output (in μmoles TBA‐MDA equivalents/day) at the end of the salmon diet feeding period was significantly greater (7.05±1.33 TBARS,P<0.05; and 7.07±1.73 TBA‐MDA adduct,P<0.01) compared to when the subjects were eating the StD (5.65±1.09 TBARS and 4.65±0.76 TBA‐MDA adduct). When the TBARS and TBA‐MDA adduct values were normalized relative to creatinine output (in nmoles TBA‐MDA equivalents/μmole creatinine), the data achieved even greater statistical significance. The mean output of the group eating the salmon diet was 0.478±0.076 for TBARS (P<0.01) and 0.476±0.082 for the TBA‐MDA adduct (P<0.001)vs. 0.345±0.059 for TBARS and 0.283±0.041 for the TBA‐MDA adduct when the subjects were consuming the StD. Thus, the consumption of cooked fish may increase one's exposure to MDA and other autoxidation products, compounds that may be carcinogenic or mutagenic.
Novel brominated phospholipid fatty acids from the Caribbean spongeAgelas sp.
Authors: Carballeira Néstor M. , Emiliano Anastacio
Published: November 2006

The very long‐chain fatty acids, (5E,9Z)‐6‐bromo‐5,9‐tetracosadienoic, (5E,9Z)‐6‐bromo‐23‐methyl‐5,9‐tetracosadienoic, (5E,9Z)‐6‐bromo‐5,9‐pentacosadienoic and (5E,9Z)‐6‐bromo‐24‐methyl‐5,9‐pentacosadienoic acids, were identified in the phospholipids (mainly phosphatidylethanolamine) of the spongeAgelas sp. Structure elucidation was accomplished by means of mass spectrometry and chemical transformations, including deuteration with Wilkinson's catalyst. All of the sterols from the sponge had the Δ5,7 nucleus, with 24‐methylcholesta‐5,7,22‐trien‐3β‐ol (ergosterol) and 24‐ethylcholesta‐5,7,22‐trien‐3β‐ol being the most abundant.
Identification of two novel dihydroxysterols fromPavlova
Authors: Patterson Gleen W. , Gladu Patricia K. , Wikfors Gary H. , Parish Edward J. , Livant Peter D. , Lusby William R.
Published: November 2006

Pavlova gyrans andP. lutheri were cultured, and the dihydroxysterols were isolated from the free sterol and the polar sterol fractions. Four dihydroxysterols were detected in amounts greater than 1% of total sterol by gas chromatography and were analyzed by gas chromatography/mass spectrometry. The two principal sterols were isolated by chromatography on alumina followed by hydrophobic Sephadex column chromatography. The two sterols appeared to differ by having either a methyl or an ethyl group at C−24; they were termed “methylpavlovol” and “ethylpavlovol.” Analysis by 400 MHz nuclear magnetic resonance showed that methylpavlovol is 4α,24β‐dimethylcholestan‐3β,4β‐diol and ethylpavlovol is 4α‐methyl,24β‐ethylcholestan‐3β,4β‐diol. The 4α‐methyl,4β‐hydroxy configuration has not been observed previously in a natural sterol. Dihydroxysterols make up approximately one‐third of the total sterols in thesePavlova species. Neither the biosynthetic origin of these dihydroxysterols nor their role in the biochemistry ofPavlova is known.
Changes in murine tissue concentrations of dolichol and dolichol derivatives associated with age
Authors: Daniels I. , Hemming F. W.
Published: November 2006

The concentrations of the three major cellular forms of dolichol (free, esterified and phosphorylated) were determined in murine liver, kidney and heart. The tissue levels of these forms of dolichol were studied in detail as a function of age. Changes in the activities of dolichyl phosphate phosphatase and dolichol kinase were also determined. In liver, the concentration of unesterified dolichol, fatty acyl dolichol and dolichyl phosphate increased markedly over a period of 6 to 25 months (four‐fold, 5.5‐fold and nine‐fold, respectively). In kidney only, free dolichol and phosphorylated dolichol increased (approximately four‐fold in each case). However, this tissue consistently showed the highest concentrations of all forms of dolichol as compared to liver and heart. In heart, both free and esterified dolichol concentrations increased (approximately 3.25‐fold in each case); dolichyl phosphate levels were not determined in this tissue. In all tissues studied, the activity of the dolichyl phosphate phosphatase enzyme was considerably higher than that of the dolichol kinase enzyme. In liver, there was no evidence to suggest that either enzyme was critical in determining the relative concentrations of dolichol and dolichyl phosphate. Evidence for such a role for the kinase in the kidney was stronger. Treatment of aging mice with meclofenoxate, a drug that is reported to cause dissolution of lipofuscin, failed to prevent accumulation of dolichol and dolichyl phosphate with age. These observations suggest that not all accumulated dolichol is associated with lipofuscin. Meclofenoxate treatment had no consistent effect on the activities of the enzymes studied.
Caecal and colonic uptake of both linoleic acid and cholesterol in rats following intestinal resection
Authors: Molina M. T. , Ruiz‐Gutierrez V. , Vazquez C. M. , Bolufer J.
Published: November 2006

Caecal and colonic uptake of both linoleic acid and cholesterol were studied in rats after distal small bowel resection (DSBR). The results showed that the surgical operation increased the caecal and colonic uptake of linoleic acid. Supplementation with linolenic acid inhibited caecal and colonic uptake of linoleic acid. Experiments carried out in the presence of rotenone and ouabain suggest that facilitated diffusion is the predominant mechanism of caecal and colonic linoleic acid absorption, at least at low concentrations. An increase in caecal and colonic uptake of cholesterol was observed after the surgical operation. The study showed that facilitated diffusion seems to be the mechanism of linoleic acid absorption in the caecum and colon, and that both organ growth and changes in transport function of the epithelial cells of caecum and colon appear to be involved in the adaptive response of the bowel to intestinal resection.
Accumulation of eicosapentaenoic acid in plasma phospholipids of subjects fed canola oil
Authors: Corner Elizabeth J. , Bruce Vivian M. , McDonald Bruce E.
Published: November 2006

The metabolism of α‐linolenic acid from canola oil was studied in eight normolipidemic men. The 42‐day study was divided into three periods: a 6‐day pre‐experimental and two 18‐day experimental. Approximately 75% of the dietary fat (28% of total energy) was provided by a mixture of fats during the pre‐experimental period and either canola oil (CO) or sunflower oil (SO) during the experimental periods. The CO and SO diets were fed in a cross‐over design. The ratios of linoleic to linolenic acid were 2.6∶1 and 73.9∶1 in the CO and SO diets, respectively. Dietary fat source had an effect on plasma phospholipid fatty acids: 18∶1n−9, 18∶3n−3 and 20∶5n−3 were higher (p<0.05), and 18∶2n−6 was lower in the phosphatidylcholine fraction; 18∶1n−9 was higher and 20∶4n−6 lower in the phosphatidyl‐ethanolamine fraction; and 18∶1n−9 and 20∶5n−3 were higher and 20∶4n−6 and 22∶6n−3 were lower in the alkenylacyl‐ethanolamine phospholipid fraction on the CO diet as compared to the SO diet. Consumption of the canola oil diet resulted in higher n−3 fatty acid levels and lower n−6 fatty acid levels in plasma phospholipids than consumption of the sunflower oil diet.
Composition of mouse peritoneal macrophage phospholipid molecular species
Authors: Akoh Casimir C. , Chapkin Robert S.
Published: November 2006

The individual molecular species composition of diacyl, alkylacyl and alkenylacyl glycerophospholipids was determined in mouse peritoneal macrophages. A marked deterogeneity in the relative composition (mol%) of macrophage ether and ester phospholipid individual species was noted. High concentrations of 16∶0–20∶4 were found in ether phospholipids such as alkenylacyl glycerophosphoethanolamine (GPE; 27.5 mol%) and alkylacyl glycerophosphocholine (GPC; 16.6%) as compared to mol % levels of 16∶0–20∶4 in diacyl GPE (5.7%) and diacyl GPC (8.1%), respectively. Interestingly, alkenylacyl GPE was highly enriched in 1‐ether (16∶0) relative to alkylacyl GPC. The predominant diacyl molecular species in glycerophosphoinositol (GPI) and glycerophosphoserine (GPS) were 18∶0–20∶4 (59.1%) and 16∶0–18∶1 (41.1%), respectively. It is noteworthy that the level of 18∶0–20∶4 was several times higher in diacyl GPI (59.1%) than in diacyl GPS (11.1%), diacyl GPE (25.7%), and diacyl GPC (3.7%). The most abundant molecular species in diacyl GPC and diacyl GPE were 16∶0–18∶1 (29.9%) and 18∶0–20∶4 (25.7%), respectively. The abundance of 20∶4 in ether phospholipids, specifically 16∶0–20∶4 and 18∶0–20∶4, in alkylacyl GPC is significant in view of the role these antecedents play in the biosynthesis of platelet‐activating factor (PAF) and 20∶4‐derived eicosanoids in stimulated macrophages. The unique molecular species composition of the peritoneal macrophage distinguishes this cell type from others.
Transformations of 5‐HETE by activated keratinocyte 15‐lipoxygenase and the activation mechanism
Authors: Green Floyd A.
Published: November 2006

There is convincing evidence that normal cultured human keratinocytes possess a 15‐lipoxygenase activity which, however, does not appear to manifest itself without cell membrane damage. When “activated”, this enzyme transforms arachidonic acid into 15‐hydroxyeicosatetraenoic acid (15‐HETE), and linoleic acid into 13‐hydroxyoctadecadienoic acid, presumably by peroxidase action on their respective hydroperoxy intermediates. Normal but notmembrane‐damaged keratinocytes metabolize exogenous 5‐HETE, principally by esterifying the eicosanoid intact, primarily in the triacylglycerol fraction. In the present study, membrane‐damaged keratinocytes were found to transform 5‐HETE to 5,15‐diHETE and also to a lipoxin‐like group of tetraenes. Similar, if not identical, tetraenes were produced by action of the keratinocyte enzyme on 5(S),15(S)‐diHETE, which points to the role of the latter as an intermediate between 5‐HETE and the tetraenes. A direction for further study of the mechanism of the “activation” step is presented.
Molecular species of 1‐O‐alk‐1′‐enyl‐2‐acyl‐, 1‐O‐alkyl‐2‐acyl‐ and 1,2‐diacyl glycerophospholipids in Japanese oysterCrassostrea gigas (Thunberg)
Authors: Yeong Bo Young , Ohshima Toshiaki , Koizumi Chiaki
Published: November 2006

Molecular species of 1‐O‐alk‐1′‐enyl‐2‐acyl‐, 1‐O‐alkyl‐2‐acyl‐, and 1,2‐diacyl‐sn‐glycero‐3‐phosphoethanolamine (EPL) andsn‐glycero‐3‐phosphocholine (CPL) of Japanese oysterCrassostrea gigas were analyzed by selectedion monitoring gas chromatography/mass spectrometry using electron impact ionization. The characteristic fragment ions, [RCH=CH+56]+ due to the alkenyl residue in thesn‐1 position and [RCO+74]+ due to the acyl residue in thesn‐2 position of alkenylacylglycerols, [R+130]+ due to the alkyl residue in thesn‐1 position and [RCO+74]+ due to the acyl residue in thesn‐2 position of alkylacylglycerols, [RCO+74]+ due to the acyl residues in thesn‐1 and/orsn‐2 positions of diacylglycerols, and [M−57]+ being indicative of the corresponding molecular weight, were used for structural assignments.

For alkenylacyl EPL and CPL, 19 and 16 molecular species were determined, respectively. Two molecular species, 18∶0alkenyl‐22∶6n−3 and 18∶0‐alkenyl‐22∶2‐non‐methylene interrupted diene (NMID), amounted to 53.2% and 47.9%, respectively. The alkylacyl EPL and CPL consisted of 16 and 20 molecular species, respectively, and the prominent components were 18∶0alkyl‐22∶2NMID, 20∶1alkyl‐20∶1n−11 (27.4%) and 20∶1alkyl‐20∶2NMID (16.3%) in the former, and 16∶0alkyl‐20∶5n−3 (23.0%) and 16∶0alkyl‐22∶6n−3 (21.6%) in the latter. For the diacyl EPL and CPL, 14 and 51 molecular species were determined, respectively. The major molecular species were 18∶0–20∶5n−3 (37.4%), 16∶0–20∶5n−3 (14.2%) and 18∶1n−7–22∶2NMID (13.2%) in the former, and 16∶0–20∶5n−3 (33.4%) and 16∶0–22∶6n−3 (22.3%) in the latter. It was found that there were significant differences in the molecular species between the alkylacyl and diacyl EPL and the alkylacyl and diacyl CPL; the number of molecular species was larger in CPL than in EPL, while the number of total carbons and double bonds of the major molecular species were larger in the EPL than in the CPL. Alkenylacyl EPL were similar to alkenylacyl CPL in molecular species composition.
Carbohydrate content of apolipoprotein B‐48 from rat chylomicrons of varying density
Authors: Bochenek Wieslaw J. , Weber Peter , Slowinska Regina , Tang Gexin , Rodgers John B.
Published: November 2006

Monosaccharide composition was determined in apolipoprotein B‐48 (apoB) of chylomicrons of rat mesenteric lymph. Chylomicrons were separated into three fractions based on density. Triglyceride and apolipoprotein content were determined in each. ApoB was isolated and quantified using precipitation with isopropanol. Chylomicrons were collected in lymph under normal conditions, and with Poloxalene 2930 when chylomicron secretion was inhibited. Most of the triglyceride was carried in the least dense fraction, while the highest apoB content was in the most dense fraction under normal conditions. Mannose and galactosamine contents of apoB were similar in all fractions while contents of both glucosamine and galactose were highest in the least dense fraction. When chylomicron secretion was inhibited by Poloxalene, the amount of triglyceride recovered in the least dense fraction was significantly reduced. Despite the inhibition of lipid transport in the least dense fraction of chylomicrons by Poloxalene, there was little change in apoB recoveries and in the relative content of various monosaccharides in the apoB from each of the three fractions as compared to results obtained during lipid absorption under normal conditions. In conclusion, carbohydrate composition of apoB of chylomicrons is heterogeneous and varies with chylomicron density.
Occurrence of long and very long polyenoic fatty acids of the n‐9 series in rat spermatozoa
Authors: Aveldaño M. I. , Rotstein N. P. , Vermouth N. T.
Published: November 2006

Dietary deficiency of essential fatty acids of the n−3 and n−6 series is known to promote a compensatory increase in polyenoic fatty acids of the n−9 series in the lipids of mammalian tissues. In the present study long‐chain n−9 polyenes were found to be normal components of the epididymis and especially of sperm isolated from that tissue, in healthy, well‐fed, fertile rats maintained on essential fatty acid‐sufficient diets. The n−9 polyenes occurred in large concentrations in the choline glycerophospholipids (CGP), the major phospholipid class of spermatozoa in epididymalcauda, and were highly concentrated in plasmenylcholine, the major subclass of CGP. The uncommon polyene 22∶4n−9 was found in the highest proportion, followed in order of relative abundance by 22∶3n−9, 20∶3n−9 and 24∶4n−9. These polyenes were probably derived from oleate (18∶1n−9) in much the same way as long‐chain polyenes of the n−6 and n−3 series are derived from linoleate (18∶2n−6) and linolenate (18∶3n−3), respectively.
Isolation and characterization of novel 2‐hydroxy fatty acids from the phospholipids of the spongeSmenospongia aurea
Authors: Carballelra Néstor M. , Emiliano Anastacio , Rodriguez Jaime , Reyes Elba D.
Published: November 2006

The Caribbean spongeSmenospongia aurea revealed the presence of six novel branched α‐hydroxy fatty acids: 2‐hydroxy‐17‐methyloctadecanoic acid, 2‐hydroxy‐21‐methyldocosanoic acid, 2‐hydroxy‐22‐methyltricosanoic acid, 2‐hydroxy‐22‐methyltetracosanoic acid, 2‐hydroxy‐24‐methylpentacosanoic acid, and 2‐hydroxy‐23‐methylpentacosanoic acid. These novel α‐hydroxy fatty acids were associated with phosphatidylethanolamine. The spongesAplysina lacunosa andAplysina fistularis also contained considerable amounts of α‐hydroxy fatty acids, the very long‐chain 5,9,23‐tricontatrienoic acid (30∶3), and phytanic acid. The sterol composition of the three sponges was also studied. It indicated thatA. lacunosa andA. fistularis contained large amounts of aplysterol and verongulasterol, whileS. aurea did not show any of these sterols. The results are discussed in terms of the taxonomy of the species.
A facile synthesis of 4‐hydroxy‐2(E)‐nonenal
Authors: Gardner H. W. , Bartelt R. J. , Weisleder D.
Published: November 2006

A facile, efficient synthesis of 4‐hydroxy‐2(E)‐nonenal is presented as an alternative to the approaches published previously, which either employed four to six separate steps or furnished low yields. The commercially available 3(Z)‐nonenol was sequentially oxidized into 3,4‐epoxynonanol by 3‐chloroperoxybenzoic acid followed by oxidation of the alcohol by periodinane to afford 4‐hydroxy‐2(E)‐nonenal by this two‐step procedure in 48±7% yield.
Omega‐3 fatty acid and cholesterol content of newly hatched chicks from α‐linolenic acid enriched eggs
Authors: Cherian G. , Sim J. S.
Published: November 2006

Egg yolk was enriched with α‐linolenic acid (18∶3n−3) by feeding laying hens diets containing flax, canola or soybean seeds. Fertilized eggs were incubated and the fatty acid composition of whole body, liver, plasma, brain and the cholesterol content of plasma and liver tissue of the hatched chicks were studied. Eggs enriched with 18∶2n−6 fatty acids by feeding hens diets containing sunflower seeds were used as the controls. Feeding flax enriched (P<0.05) egg yolk and the developing progeny with 18∶3n−3, 20∶5n−3, 22∶5n−3 and 22∶6n−3. Feeding sunflower seeds resulted in an increase (P<0.05) of 18∶2n−6, 20∶4n−6, 22∶4n−6 and 22∶5n−6. The predominant polyunsaturated fatty acid of the brain was docosahexaenoic acid (22∶6n−3) which was higher (P<0.05) in the flax and canola fed group. The cholesterol content of the liver tissue was lower (P<0.05) in chicks hatched from hens fed flax seeds. This study indicates that 18∶3n−3 and 18∶2n−6 in the maternal diet are potent modulators of long‐chain polyunsaturated n−3 or n−6 fatty acid and of cholesterol content in the developing progeny.
Inhibition of phenytoin bioactivation and teratogenicity by dietary n−3 fatty acids in mice
Authors: Kubow Stan
Published: November 2006

Evidence suggests that the teratogenicity of the anticonvulsant drug phenytoin (DPH) can result from its bioactivationvia embryonic prostaglandin synthase and/or maternal cytochromes P450. This study examined whether DPH bioactivation and teratogenicity could be reduced by dietary n−3 fatty acids. Female CD‐1 mice were fed diets containing 2 wt% safflower oil and 10 wt% of either hydrogenated coconut oil, safflower oil, or a cod liver oil/linseed oil mixture (CLO/LO) for three weeks prior to impregnation and throughout gestation. DPH (55 or 65 mg/kg) was administeredvia intraperitoneal injections to pregnant mice at 0900 on gestational days 12 and 13, and on day 19 fetuses were given teratologic assessments. A similar dietary study evaluatedin vivo covalent binding of radiolabeled DPH administered on day 12, and dams were killed 24 h later. A reduction in DPH‐induced cleft palates and a decrease in DPH covalent binding to embryonic protein was observed in the CLO/LO group. Feeding CLO/LO enhanced incorporation of n−3 fatty acids into embryos and inhibited embryonic prostaglandin synthase activity. No differences in maternal hepatic cytochromes P450 activities were observed among dietary treatments. These data indicate that dietary n−3 fatty acids could reduce DPH teratogenicityvia inhibition of embryonic prostaglandin synthase bioactivation of DPH.
Plasma lipids and fatty acids in urbanized Bushmen, Hereros and Kavangos of Southern Africa (Namibia)
Authors: Tichelaar H. Y. , Benadé A. J. S. , O'Keefe S. J. D. , Jooste P. L. , Swanevelder S. A. , Van Staden E.
Published: November 2006

Thirty‐nine urbanized ethnic Namibian people comprising 21 Bushmen (semi‐urbanized), 7 Hereros and 11 Kavangos were assessed for plasma lipids and fatty acid (FA) composition. Total cholesterol and triacylglycerol concentrations were measured by enzymatic methods, and neutral lipid FA composition by gas‐liquid chromatography. The results demonstrated that while total cholesterol concentrations were not significantly different, significant differences in triacylglycerol concentrations (P<0.05) were seen between Bushmen and Kavangos. By comparing Bushmen with Hereros and Kavangos, significant differences between Bushmen and Kavangos were also observed in plasma triacylglycerol FA compositions, particularly 16∶0 (32.73%vs. 25.05%), 16∶1n−7 (7.00%vs. 5.06%), 18∶2n−6 (9.30%vs. 22.25%) and 20∶3n−6 (0.12%vs. 0.48%), while Kavangos had higher 20∶4n−6 levels than Hereros (1.44%vs. 2.00%). In plasma cholesteryl esters, Bushmen were significantly different from Kavangos in 16∶1n−7 (8.85%vs. 4.93%), 18∶1n−9 (32.06%vs. 23.07%) and 20∶4n−6 (6.91%vs. 10.00%). Significant differences were also observed between Bushmen and Hereros in 18∶0 (1.08%vs. 1.29%) and 18∶2n−6 (35.68%vs. 45.50%). The FA of Namibian groups were also compared with South African reference groups comprising urbanized whites and Xhosas and rural Vendas. The differences in blood lipid values can be explained primarily by excessive alcohol consumption. These results suggest that semi‐urbanized Bushmen have changed their diets under urbanized conditions which may increase their risk of coronary heart disease.
The gastrointestinal handling and metabolism of [1‐13C]palmitic acid in healthy women
Authors: Murphy Jane L. , Jones Amanda , Brookes Steven , Wootton Stephen A.
Published: November 2006

The gastrointestinal handling and metabolism of [1‐13C]palmitic acid given as the free fatty acid was examined in six healthy women by measuring the excretion of13C‐label in stool and in breath as13CO2. The gastrointestinal handling of [1‐13C]palmitic acid was compared with the apparent absorption of dietary lipid by measuring lipid losses in stool. The variation both within and between subjects was determined by repeating the study in the same individuals on separate occasions. The time course for excretion of label in stool over the five‐day study period followed a common pattern, with most of the label excreted over the first two days of the stool collection.13C‐Label excreted in stool over the five‐day study period was 14.3±9.8% of that administered and on repeating the trial was 31.6±24.7% (not significantly different due to variability); there was poor agreement within subjects. Lipid excreted in stool expressed as a percentage of ingested lipid was 5.2±4.4% in Trial 1 and 5.9±4.0% in Trial 2, and was the same in each individual on repeating the trial. There was no clear relationship between the excretion of13C‐label and lipid in stool (Trial 1:R=−0.43,P>0.40; Trial 2:R=−0.02,P>0.97). On the first occasion, 22.0±4.5% of the administered label was excreted on breath over the 15‐h study period and on repeating the trial was 15.8±9.5% (not significantly different) with poor repeatability in a given individual. There was an inverse relationship between the proportion of13C‐label excreted in stool and that excreted on breath in Trial 1 (R=−0.80,P>0.06) with a weaker association observed in Trial 2 (R=−0.49,P>0.32). Correcting for differences in the apparent absorption of label reduced the variability in its excretion in breath observed between subjects, particularly in Trial 2. It is concluded that although there are differences in the gastrointestinal handling of [1‐13C]palmitic acid both within and between healthy adults, the postprandial oxidation of absorbed substrate was similar. The assumptions underlying these observations need to be examined by characterizing the nature of13C‐label in stool.
Dietary fat alters the distribution of cholesterol between vesicles and micelles in hamster bile
Authors: Cohen Bertram I. , Mikami Takahiro , Ayyad Nariman , Mikami Yasuko , Mosbach Erwin H.
Published: November 2006

The type of dietary fat strongly affects the incidence of gallstones in the hamster model of cholesterol cholelithiasis. The present study was designed to determine whether dietary fats could affect gallstone formation by altering the microstructure (vesicular/micellar ratio) of cholesterol in bile. Golden Syrian hamsters from Sasco (Omaha, NE) or Charles River (Wilmington, MA) were fed nutritionally adequate semipurified diets to which were added: (i) 4.0% butterfat without added cholesterol; (ii) 1.2% palmitic acid plus 0.3% cholesterol; or (iii) 4.0% safflower oil plus 0.3% cholesterol. Gallstone incidence and the percentage of cholesterol in vesicles and micelles were determined after two‐ or six‐week feeding periods. Three out of ten Sasco hamsters fed the 1.2% palmitic acid diet for two weeks had cholesterol stones, while none of the eight Charles River animals had stones. In the Sasco hamsters, a significant proportion of the biliary cholesterol was found in void volume vesicles (28.8%) and small vesicles (17.1%); Charles River hamsters had negligible proportions (1.1%) of cholesterol in void volume vesicles and 15.4% in small vesicles. Cholesterol gallstones were most abundant in Sasco hamsters fed 1.2% palmitic acid for six weeks (nine out of ten animals); the mean cholesterol saturation index of the bile was 1.27. A significant proportion of the biliary cholesterol was eluted in the void volume vesicles (21.4%) and in small vesicles (15.0%). Five of the eight identically treated Charles River hamsters had cholesterol stones; the cholesterol saturation index averaged 1.36, and the biliary cholesterol was present in void volume vesicles (31.3%) and small vesicles (14.3%). Vesicles were not detected in the bile of hamsters fed cholesterol‐free diets, and none of these animals developed cholesterol gallstones. Safflower oil diets inhibited stone formation even though the cholesterol saturation index was above unity. After six weeks, biliary cholesterol transported in void volume vesicles was highest for Sasco hamsters (13.3%) as compared to Charles River animals (6.9%), but total cholesterol transported in void volume vesicles plus small vesicles was similar in both groups (33.5% vs. 26.2%), respectively. These results suggest that in both strains of hamsters dietary fat influences gallstone formation by modulating the vesicular/micellar distribution of biliary cholesterol. Apparently, the presence of cholesterol/phospholipid vesicles in bile is associated with cholesterol gallstone formation.
Induction of geranyl pyrophosphate pyrophosphatase activity by cholesterol‐suppressive isoprenoids
Authors: Case Gary L. , He Lei , Mo Huanbiao , Elson Charles E.
Published: November 2006

Diets supplemented (1 mmol/kg) with thymol, carvacrol, and β‐ionone significantly decreased the serum cholesterol levels of cockerels. These mevalonate‐derived end products of plant secondary metabolism (isoprenoids) had no impact on two cytosolic prenyl alcohol (and ethanol) dehydrogenase activities; each treatment increased microsomal geranyl pyrophosphate pyrophosphatase activity by greater than twofold. The structural diversity of the isoprenoids which suppress cholesterol synthesis may be reconciled by their ability to increase pyrophosphatase activity, thus leading to the production of the endogenous, post‐transcriptional regulator of 3‐hydroxy‐3‐methyglutaryl coenzyme A reductase activity.
Effects of pregnenolone‐16α‐carbonitrile on the metabolism of cholesterol in rat liver microsomes
Authors: Ståhlberg Dagny
Published: November 2006

The effects of pregnenolone‐16α‐carbonitrile (PCN) on hepatic metabolism of cholesterol were studied in rat liver microsomes in order to clarify the underlying mechanisms of the PCN‐induced biliary hypersecretion of cholesterol. Male Sprague‐Dawley rats were fed a diet supplemented with 0.05% of PCN for one week. The microsomal activity of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase, regulating cholesterol biosynthesis, decreased from 577 ± 46 (SEM) to 367 ± 38 pmol/min/mg protein compared to the controls. Cholesterol 7 α‐hydroxylase activity, governing bile acid synthesis, was 9.0 ± 1.1 pmol/min/mg protein in the treated group and 34.8 ± 7.4 pmol/min/mg protein in the controls, a reduction of 74% (P<0.01). The acyl CoA:cholesterol acyltransferase (ACAT) activity, catalyzing the esterification of cholesterol, remained unchanged, as did the levels of total and free cholesterol in liver homogenates and microsomes. The results of this study provide evidence that the increase in biliary cholesterol secretion during PCN treatment is not caused by a change in ACAT activity, but can be explained by a decreased catabolism of cholesterol to bile acids.
Lipid biosynthesis in cultured arterial smooth muscle cells is related to their phenotype
Authors: Dusserre Eric , Bourdillon Marie‐Claude , Ciavatti Maryvonne , Covacho Chantal , Renaud Serge
Published: November 2006

During the atherogenic processin vivo, arterial smooth muscle cells (SMC) undergo changes in their phenotype. In the present study, rat SMC from primary cultures and from subcultures before 10 and after 200 passages, showing contractile‐like, synthetic and transformed phenotypes, respectively, were compared in regard to their lipid content and biosynthesis. The rationale for comparing these phenotypes rests in the similar changes in phenotype of SMC that occur in the formation and progression of atherosclerotic lesions. Phenotype changes were shown to be associated with changes in the phospholipid content of SMC. Phospholipid levels increased, but not as significantly as did cholesterol levels when passing from contractile to synthetic and transformed cells (1.23±0.18, 2.28±0.26 and 3.25±0.23 μg/106 cells, respectively). Cholesterol normalized in respect to cell protein was increased to the same extent. Lipid synthesis as judged by [14C]acetate incorporation was increased 3‐ to 12‐fold in the synthetic and transformed cells, respectively, compared to contractile cells. After thin‐layer chromatography, radioactivity was shown to be markedly increased in most of the lipid fractions, but label in the cholesterol fraction of synthetic and transformed cells was increased by 7‐ and 21‐fold, respectively. Thus, SMCin vitro were shown to drastically increase cholesterol biosynthesis associated with phenotype changes. Such changes are known to occurin vivo and might represent a critical step in the deposition of excess cholesterol within foam cells.
The esterified plasma fatty acid profile is altered in early HIV‐1 infection
Authors: Peck Michael D. , Mantero‐Atienza Emilio , Miguez‐Burbano Maria Jose , Fletcher Mary Ann , Shor‐Posner Gail , Baum Marianna K.
Published: November 2006

Previous studies have shown that alterations in micronutrient utilization occur in patients with Acquired Immune Deficiency Syndrome. In this study, total plasma fatty acid composition was measured in 36 homosexual men infected with the Human Immunodeficiency Virus 1 (HIV‐1) and in 17 HIV‐1 seronegative homosexual men in order to evaluate differences associated with early HIV‐1 infection. Immunologic assessment included CD4 cell number count and lymphocyte blastogenesis in response to the mitogens phytohemagglutinin (PHA) and pokeweed (PWM). The mean total amount of ω6 polyunsaturated fatty acids (18∶2 and 20∶4) was significantly lower in the HIV‐1 seropositive subjects (38±8.1% SD) as compared to HIV‐1 seronegative subjects (43±4.2%;P=0.0027). This was also reflected in a higher level of total saturated fatty acids (16∶0 and 18∶0) in HIV‐1 seropositive subjects (30±2.2%vs. 26±2.8%;P=0.0001). The ratio of linoleic to arachidonic acid (18∶2 to 20∶4) was higher in the HIV‐1 seronegative group (6.76±4.88) compared to the HIV‐1 seronegative group (4.86±1.37;P=0.0213). The response to PHA in seropositive subjects correlated inversely with total plasma ω6 fatty acids (r=−0.36;P=0.027), and directly with the 18∶2 to 20∶4 ratio (r=0.33;P=0.046). CD4 cell counts and the response to PWM did not correlate with plasma fatty acid levels in HIV‐1 seropositive subjects. We conclude that early HIV‐1 infection is associated with lower plasma ω6 polyunsaturated fatty acids, notably arachidonic acid, than are controls, and that the changes in the plasma fatty acid profile correlate with some indices of immune function.
Adipose glycerolipid formation: Effect of nutritional and hormonal states
Authors: Jamdar Subhash C. , Cao Wang Fang
Published: November 2006

The potential of glycerolipid formation fromsn‐glycerol‐3‐phosphate (GP) and 2‐monoacylglycerol (MG) was studied in adipose microsomal fractions under various nutritional and hormonal states. Glycerolipid formation from GP was followed in the presence of [14C]glycerol‐3‐phosphate and palmitoyl‐CoA and was assayed by measuring the formation of butanol‐soluble product, consisting mainly of [14C]phosphatidate. Glycerolipid formation from MG was determined in the presence of 2‐monooleyl glycerol and [14C]palmitoyl‐CoA, and was estimated by the formation of both [14C]di‐ and triacylglycerol. Glycerolipid formation from GP was decreased significantly during food deprivation, in experimental diabetes, in the presence of lipolytic hormone, and during aging. Glycerolipid formation from MG did not change under these conditions and continued at the same rate as observed in control animals. The rate of glycerolipid formation from GP was 7–20 times greater than from MG in the various fat depots. Measurement of the adipose mono‐acylglycerol concentration did not show any correlation with the glycerolipid formation from MG. The studies suggest that glycerolipid formation from MG is active in various fat depots, and is substantial when glycerolipid formationvia GP is impaired.
Nervonic acid in red blood cell sphingomyelin in premature infants: An index of myelin maturation?
Authors: Babin F. , Sarda P. , Limasset B. , Descomps B. , Rieu D. , Mendy F. , Crastes de Paulet A.
Published: November 2006

The present study addresses the question whether nervonic acid (24∶1n−9) accumulation in sphingomyelin (SM) of red blood cells (RBC) could yield information on cerebrum maturation in premature infants. The study included 28 premature eutrophic infants of 31.5 wk gestational age. Eleven were fed with human milk, nine with a regulator formula and eight with an α‐linolenate‐enriched formula. The fatty acid composition of the SM fraction was determined by gas‐liquid chromatography on a 50‐m fused silica capillary column. At 32 wk gestational age, the main fatty acids in SM were 16∶0, 18∶0, 20∶0, 22∶0, 24∶0 and 24∶1n−9. After five weeks of feeding, at week 37 of postconceptional age, the most striking variation was a rise in 24∶1n−9, from 9.9±0.7 to 12.8±0.9 (P<0.02), regardless of regimen in all three feeding groups. The rise in 24∶1n−9 after birth in premature eutrophic infants is the beginning of a trend toward the higher levels in 24∶1n−9 observed in mature newborns and older infants. The 24∶1n−9 level in SM of RBC from premature infants may reflect 24∶1n−9 levels in SM of brain and could thus reflect brain maturity.