bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholesterol metabolism in human monocyte‐derived macrophages: Stimulation of cholesteryl ester formation and cholesterol excretion by serum lipoproteins
Authors: Albert Daniel H. , Traber Maret G. , Kayden Herbert J. 
Published: December 2006

AbstractThe role of lipoproteins and serum in the formation and accumulation of cholesteryl esters in human monocyte‐derived macrophages (HMD macrophages) was investigated; studies were also carried out with IC21 cells (a cell line derived from mouse peritoneal macrophages). Following preincubation of HMD macrophages with lipoprotein‐depleted serum (LPDS), both native and acetylated low density lipoprotein (LDL and AcLDL, respectively) stimulated the formation of cholesteryl esters with a resultant increase in cellular cholesteryl ester content. Cholesteryl ester formation and accumulation was also stimulated in macrophages exposed continuously to 25‐hydroxycholesterol. However, the stimulation of cholesterol esterification by either lipoproteins or 25‐hydroxycholesterol was not inhibited by progesterone in HMD macrophages, but was in the IC21 cells. Cholesterol efflux and the hydrolysis of cellular cholesterol ester, promoted by serum components, were studied in HMD macrophages preloaded with cholesteryl ester by incubation with 25‐hydroxy cholesterol. Replacement of the medium with one devoid of 25‐hydroxycholesterol resulted within 24 hr in at least a 30% decrease in the cholesteryl ester content of the HMD macrophages; replacement with a medium high in cholesterol acceptor content (LPDS or high density lipoprotein) and incubation for three days led to the most marked decreases in cellular cholesterol content. Thus, hydrolysis of the cholesteryl esters by HMD macrophages was not dependent on the presence of cholesterol acceptors in the medium, but cellular cholesterol content was.
Inhibition of lymphocyte capping by fatty acids in mouse and man
Authors: Santiago‐Delpín Eduardo A. , Román‐Franco Angel A. , Colón Julio I. 
Published: December 2006

AbstractLipid‐enriched diets have been related to a high cancer incidence in experimental animals for many years, and more recently, to assorted defects on the immune response. We investigated the effect of incubating human or murine (C3H/HEJ) lymphocytes with saturated (16∶0) and unsaturated (18∶1, 18∶2, 18∶3, 20∶4) fatty acids (12 μg for each 107 cells), on the ability to cap with andhuman or anti‐mouse anti‐IgM, μ‐chain specific antibody. Capping was also tested in obese (ob/ob, C57BL/6J) mice. Capping at 30 and 60 min was reduced by fatty acid incubation to 10–30% of control values in humans (p<.001), and to 30% of control values in mice (p<.01), regardless of degree of unsaturation. ob/ob capped normally. A lymphocyte membrane effect caused by fatty acids is observed in these experiments. Whether this is related to the dysimmunity caused by lipid diets cannot be assessed from our data, especially since all fatty acids, regardless of unsaturation, reduced the capping phenomenon.
A study of the plasma lipoproteins and the tissue lipids of the migrating lamprey,Mordacia mordax
Authors: Fellows Florence C. I. , McLean Robyn M. 
Published: December 2006

AbstractSea lampreys,Mordacia mordax, were collected in spring from the Yarra River, Victoria, during their upstream spawning migration, to study the lipid composition in their tissues and plasma and their lipid transport system. Plasma lipoproteins were isolated by preparative ultracentrifugation and their chemical compositions were analyzed. The major classes of lipoproteins were found to be similar to those of man and higher animals. Lipids from the muscle and liver were analyzed for fatty acids. The striking feature of the lipids in the migrating lamprey is the presence of very high levels of cholesterol in both plasma and muscle. The possible metabolic roles of cholesterol have been discussed.
Synthesis of diene prostaglandins in freshwater fish
Authors: Bandyopadhyay Gautam K. , Dutta Jyotirmoy , Ghosh Sudhamoy 
Published: December 2006

AbstractBiosynthesis of PGD2, PGE2 and PGF2α in four species of freshwter fish,Tilapia mossambica, Cyprinus carpio, Heteropneustes fossilis andClarius batrichus was studied. Both arachidonic acid and PGH2 were used as substrates. When PGH2 replaced arachidonic acid in the enzymic reaction, there was a 3‐ to 4‐fold increase in PGE2 synthesis, but no such increase in the synthesis of PGF2α and PGD2 was observed.
The distribution of cholesterol and phospholipid composition in submitochondrial membranes from bovine adrenal cortex: Fundamental studies of steroidogenic mitochondria
Authors: Cheng Behling , Kimura Tokuji 
Published: December 2006

AbstractThe cholesterol contents and phospholipid compositions of mitochondria, microsomes and submitochondrial membranes from bovine adrenal cortex have been analyzed quantitatively. From our results, the following cholesterol contents were obtained: mitochondria, 6.2±0.9 mol %; microsomes, 18.4±2.8 mol %; mitochondrial inner membrane, 2.8±0.6 mol %; and mitochondrial outer membrane, 8.3±1.3 mol %. In addition, the phospholipid compositions of the mitochondrial inner and outer membranes were determined for the first time. Cardiolipin was found to be enriched in the inner membrane, whereas phosphatidylinositol was richer in the outer membrane. The general features of phospholipid compositions in the submitochondrial membranes resembled that of rat liver mitochondria.
Occurrence of wax esters in the tissues of the organge roughy (Hoplostethus atlanticus)
Authors: Grigor Murray R. , Thomas Colin R. , Jones Paul D. , Buisson David H. 
Published: December 2006

AbstractThe skin, skeleton and a fat‐filled swim bladder of the orange roughy (Hoplostethus atlanticus) each contained greater than 20% lipid by wet weight which was almost entirely wax esters. These had carbon numbers of 34–40 consistent with the major fatty acid being 18∶1 and the major fatty alcohols being 16∶0, 18∶1, 20∶1 and 22∶1. In contrast, the liver and the roe contained appreciable quantities of glycerolipids with 18∶1 and 22∶6 as the major fatty acids.
Variation of cyclopropenoid fatty acids in cottonseed lipids
Authors: Fisher Gordon S. , Cherry John P. 
Published: December 2006

AbstractThe proportions of the cyclopropenoid fatty acids (CPA) esters, malvalate and sterculate, varied little in lipids from individual cottonseeds. Coefficients of variation were 10% and 20% for seeds from a lock and 13 varieities, respectively. Within the seed, variations in CPA concentrations were very large. Cyclopropenoid fatty acid concentration in the lipids decreased from 28% in the root tip to 2% in the top of the axis, and to 0.02% in the portion of the cotyledons nearest to the hull. The axial portion was only ca. 5% of the kernel, yet it contained 75% of the CPA. Distribution of dihydrosterculic acid, the precursor of CPA, was similar to that of CPA. High concentrations of CPA were found in immature seeds, root tip and radicle of germinated seeds, and root tips of cotton plants.
Studies on the half‐life and the distribution of stearoyl‐CoA desaturase in the housefly
Authors: Wang Danny L. , Reitz Ronald C. 
Published: December 2006

AbstractThe half‐life of the stearoyl‐CoA desaturase was determined by using houseflies injected with puromycin. The LD50 for puromycin was determined to be 1.55 μ g/mg body wt for both sexes. By following the decay in specific activity of the desaturase after puromycin injection, the half‐life of this enzyme in 4‐day‐old females was calculated to be 9.35 hr, while in 1‐day‐old females it was 3.38 hr. The inhibition curve for the 3‐day‐old males never reached 100%, and a biphasic curve was observed. The early phase resulted in a half‐life of the desaturase of 2.41 hr, while the latter phase had a half‐life of 8.45 hr. In general, it appeared that the half‐life of the desaturase increased with age in either sex. Studies on the distribution of desaturase activity within the housefly showed that most of the activity was present in the integument; however, in the female, the onset of ovarian development seemed to shift the distribution of desaturase from the integument, towards the internal tissues. In the male, there appeared to be equal amounts of desaturase in integument and the fat body plus internal tissues at day 2, but by day 5 most of the activity was associated with the integument. The high specific activity and high percentage of total desaturase activity associated with integument coupled with the shift of distribution of desaturase in females during the onset of ovarian development may be indicative of a close correlation of the desaturase with alkene synthesis and possibly sex pheromone production.
Evaluation of the rapid micromethod for ultracentrifugal separation of labeled plasma lipoproteins
Authors: Shireman Rachel B. , Williams Debbie 
Published: December 2006

AbstractThe fractionations of plasma lipoproteins by 2 methods were compared to evaluate the rapid separation (Airfuge®) method for lipoprotein distribution studies. When [125I] labeled very low density, low density, and high density lipoproteins (VLDL, LDL, HDL), were separately centrifuged in buffers at d=1.006, 1.06 or 1.2 g/ml by the conventional ultracentrifuge and the Airfuge®, separations of the fractions in the Airfuge® were incomplete at both 5 C and 24 C, especially at d=1.006. [3H] Benzo (a)pyrene, when added to plasma, associates with the plasma proteins and lipoproteins, especially LDL. Compared to the standard techniques, the Airfuge® method greatly overestimated its distribution into VLDL. The distribution of [3H] vitamin D3 into the VLDL plus LDL fraction was also overestimated by the Airfuge® procedure. It is concluded that caution should be observed in quantitative studies of lipoproteins in the Airfuge®. A careful comparison of the distribution into or fractionation of lipoproteins by the 2 methods should always precede any quantitative determinations involving the Airfuge®.
Evidence that chlorpromazine inhibits sterologenesis at post‐HMGCoA reductase sites in rat liver, in vitro
Authors: Bell Frank P. , Hubert E. V. 
Published: December 2006

AbstractThe mechanism by which chlorpromazine inhibits cholesterogenesis in rat liver was investigated in vitro with the use of [14C] acetate and [14C] mevalonate as sterol precursors. Evidence was obtained that chlopromazine blocks cholesterogenesis at multiple sites beyond HMGCoA reductase (β‐hydroxy‐β‐methylglutarylCoA reductase, EC 1.1.1.34), the rate‐limiting step. Squalene synthesis from both labeled acetate and mevalonate is reduced to a similar extent in the presence of chlorpromazine (29–36% at 0.5 mM). The data indicate that there is also an impairment of conversion of squalene to lanosterol, and of lanosterol to cholesterol. Overall inhibition of cholesterogenesis by chlorpromazine reached 65–75% at 0.5 mM and was concentration‐dependent over the range 0.15–1.0 mM.
Biosynthesis of long‐chain polyenoic acids from arachidonic acid in cultures of enriched spermatocytes and spermatids from mouse testis
Authors: Grogan W. McLean , Huth Ellen G. 
Published: December 2006

AbstractPrimary spermatocytes (PS), round spermatids (RS) and condensing spermatids (CS) from mouse testes were enriched on Sta‐Put 1×g density gradients and cultured for 22 or 44 hr in the presence of [1‐14C]arachidonate. Mass and radioactivity were measured by gas radiochromatography of constituent fatty acids of the various complex lipid classes fractionated by thin layer chromatography. Patterns and levels of incorporation were compared with those of whole testis, both in vitro and in vivo. The 20∶4, 22∶4, 22∶5, 24∶4 and 24∶5 of the germinal cells contained levels of radioactivity in each lipid class which were consistent with an important role for the germinal cells in long‐chain polyenoic acid (LCPA) metabolism. Cells which represented later stages of spermatogenesis (RS, CS) incorporated much higher percentages and absolute amounts of radioactivity into the fatty acids derived from 20∶4 by elongation‐desaturation pathways than did PS or whole testis in vitro. These differences were most pronounced in triacylglycerol of CS. Distributions of mass and radioactivity among lipid classes suggest synthesis of triacylglycerol by CS with a high degree of specificity for 22 or 24 carbon LCPA at thesn‐3 position.
Increases in hyperlipoproteinemia, disturbances in cholesterol metabolism and atherosclerosis induced by dietary restriction in rabbits fed a cholesterol‐rich diet
Authors: Lacombe Christiane , Corraze Genevieve , Nibbelink Maryse 
Published: December 2006

AbstractThe influence of dietary restriction on cholesterol transport and metabolism was investigated in rabbits given standard or cholesterol‐rich diets (0.2 g cholesterol/kg body weight daily) eitherad libitum or with 50% caloric ration. Dietary restriction which has only a slight influence in control rabbits markedly aggravated the disturbances induced by exogenous cholesterol. With limited feeding, control rabbits presented a moderate increase in plasma cholesterol, whereas marked aggravation of hypercholesterolemia was observed in cholesterol‐fed rabbits. Analysis of the lipoprotein profile showed that the excess of plasma cholesterol with the restricted cholesterol‐rich diet corresponded to an increase in the concentration of very low density lipoprotein (VLDL) and low density lipoproteins (LDL) without any additional changes in the composition of these lipoproteins. No significant change appeared in the high density lipoprotein (HDL) concentration. The parameters of cholesterol metabolism were determined, from the curves of [3H] cholesterol radioactivity decrease, using a two‐pool model. The increase in cholesterol turnover rate induced by the cholesterol‐rich diet was accentuated by dietary restriction, whereas rabbits on standard restricted diet showed a slight decrease. The large increase in the size of both pools A and B in cholesterol‐fed rabbits was even more pronounced with limited feeding. Dietary restriction induced additional accumulation of cholesterol in the aortic wall and the grade of the lesions was also aggravated.
Stereospecificity of different lipases
Authors: Akesson B. , Gronowitz S. , Herslöf B. , Michelsen P. , Olivecrona T. 
Published: December 2006

AbstractThe stereospecificity of 4 lipases towards enantiomeric alkyldiacylglycerols and alkylmonoacylglycerols was investigated. No stereospecific breakdown of the former substrate was observed for lipases from pancreas,Rhizopus arrhizus, Pseudomonas fluorescens, or bile salt‐stimulated lipase from human milk. All lipases degraded 2‐oleoyl‐3‐tetradecyl‐sn‐glycerol faster than 1‐tetradecyl‐2‐oleoyl‐sn‐glycerol. Among X‐1‐acyl‐3‐alkylglycerol isomers, 1‐acyl‐3‐alkyl‐sn‐glycerol was preferentially attacked by the 3 first mentioned lipases. Possible mechanisms and metabolic implications for these stereospecificities are discussed.
Bromine levels in tissue lipids of rats fed brominated fatty acids
Authors: Jones Barbara A. , Tinsley Ian J. , Lowry Robert R. 
Published: December 2006

AbstractRats have been fed diets containing either 0.8% brominated corn oil or 0.5% of the ethyl ester of 9,10‐dibromostearate or 9,10,12,13‐tetrabromostearate. The brominated compounds were incorporated into semisynthetic diets and animals were observed after feeding periods of 5 days to 3 months. With the exception of adipose tissues, the highest concentration of lipid‐bound bromine was observed after 5 days on the experimental diets. It was also observed that feeding of the dibromostearate resulted in the highest levels of lipid‐bound bromine in heart, whereas the tetrabromostearate tended to result in higher levels of lipid‐bound bromine in liver. Brominated corn oil produced more substantial changes than the brominated fatty acid esters, inducing fatty livers and enlarged yellow hearts. Microscopic examination indicated myocardial degeneration and occasional early necrosis.
Toxicology of brominated fatty acids: Metabolite concentration and heart and liver changes
Authors: Jones Barbara A. , Tinsley Ian J. , Wilson Glenn , Lowry Robert R. 
Published: December 2006

AbstractRats were fed for 35 days diets containing 2% of either brominated corn oil (BCO), monoglyceride of dibromostearate (DBS), monoglyceride of tetrabromostearate (TBS) or a mixture of the two monoglycerides (BMG) which provided proportions of brominated acids comparable to that of the BCO. Hearts from all animals fed BCO were yellow colored and firm in texture. Myocardial cellular degeneration, mild to moderate edema and occasional small necrotic foci were observed. Hearts from animals fed DBS showed moderate edema and some slight necrosis. All diets produced an increase in lipid content of heart. Animals fed the experimental diets developed enlarged livers and showed elevated liver lipid content. The tetrabromostearate appeared to be the more active in producing these changes, in particular a severe intracellular fatty degeneration. Shorter‐chain (C‐16, C‐14) metabolites of di‐ and tetrabromostearate were identified and the concentration of brominated fatty acids in heart, liver and adipose tissue determined and found to account for 80% of the bromine detected in these tissues by neutron activation analysis. TBS accumulated in liver while the highest concentration of DBS was observed in heart lipids. Although the concentrations of brominated acids in heart and liver lipids were comparable in rats fed BCO or BMG, BCO produced the more pronounced effects. This differential could be due to additional active components in BCO or to a variation in response associated with changes in the location of the fatty acid on the glycerol molecule.
Altered microsomal phospholipid composition in the streptozotocin diabetic rat
Authors: Faas Fred H. , Carter William J. 
Published: December 2006

AbstractStreptozotocin diabetes in the rat alters liver microsomal membrane fatty acid composition. The present study was undertaken to determine if such changes in fatty acid composition were due to changes in the amount of individual phosphoglycerides or to disproportionate changes in fatty acid composition in any of the individual phosphoglycerides. The diabetic animals showed a small increase in total microsomal phospholipid, which is due to a selective increase in the phosphatidylethanolamine fraction. The changes in fatty acid composition in the total lipid extract (decreased palmitoleic, oleic and arachidonic acids and increased linoleic and docosahexaenoic acids) from the diabetic animals were present in both the major phosphoglycerides, phosphatidylcholine and phosphatidylethanolamine, with very little change in fatty acid composition in the phosphatidylserine and inositol fraction. Further studies are necessary to delineate the cause of the abnormal membrane phospholipid composition in the diabetic animal.
Effect of ingestion of thermally oxidized frying oil on peroxidative criteria in rats
Authors: Izaki Yaeko , Yoshikawa Shunichi , Uchiyama Mitsuru 
Published: December 2006

AbstractThermally oxidized rapeseed oils (4 levels of deterioration; used by a manufacturer of fried fish paste in a conventional manner) were fed to rats at a practical level of concentration. Rats were fed a diet ad libitum for 13 weeks that contained 15% of a test oil. The effects of the diet on several biochemical criteria related to peroxidative alterations were investigated.In groups given thermally oxidized oils relative liver weight, relative kidney weight, thiobarbituric acid‐reactive substances (TBA‐RS) in the liver and reduced glutathione content were increased significantly in proportion to the degree of deterioration of the oil, compared with the group given fresh oil. Tocopherol contents in both serum and liver were decreased considerably in proportion to the deterioration level of the supplied oils.The above criteria correlated well with various deterioration indices of the oil. For instance, TBA‐RS was well correlated (p<0.001) with petroleum ether‐insoluble oxidized fatty acid (r=0.9191), column chromatographically separated polar fraction (r=0.9056), glyceride dimer fraction (r=0.9023) and carbonyl value (r=0.8647).
Fatty acid metabolism in young oysters,Crassostrea gigas: Polyunsaturated fatty acids
Authors: Waldock M. J. , Holland D. L. 
Published: December 2006

AbstractTetraselmis suecica andDunaliella tertiolecta were grown for 24 hr in the presence of14C sodium bicarbonate and then fed separately to batches of juvenile oysters,Crassostrea gigas, for 3 days.D. tertiolecta contained fatty acids no longer than C18; 22∶6ω3 was absent inT. suecica. Analysis of the oyster fatty acids by radio gas chromatography (GC) showed that oysters were able to incorporate some of the dietary14C label into long‐chain fatty acids not supplied in the diet, e.g., C20 and C22 mono‐ and polyunsaturated fatty acids, and particularly 20∶5ω3. However, the low14C incorporation into fatty acids longer or more unsaturated than those supplied in the diet suggests that elongation and desaturation activity in young oysters is not sufficient to sustain optimum growth.
Metabolism of arachidonate in rat testis: Characterization of 26–30 carbon polyenoic acids
Authors: Grogan W. McLean 
Published: December 2006

AbstractFatty acid methyl esters of long‐chain polyenoic fatty acids (LCPA) from rat testis injected with [1‐14C] arachidonate were analyzed and separated by reversed‐phase high performance liquid chromatography (RP‐HPLC). Earlier, all previously identified LCPA were prepared in high purity along with 4 previously unidentified fatty acids, which were further characterized by capillary gas chromatography (GC), catalytic hydrogenation and alkaline isomerization. Unidentified fatty acids proved to be 26∶4, 26∶5, 28∶5 and 30∶5. All of these LCPA incorporated14C from arachidonate (20∶4) to specific activities that were comparable to that of 20∶4 and previously identified metabolites of 20∶4 and much greater than specific activities of 18∶1n−9 or 22∶6n−3. LCPA were analyzed on a capillary GC system capable of resolving knowncis‐trans and positional isomers of the n−3, n−6, n−7 and n−9 families of unsaturated fatty acids. Log plots of isothermal retention times and normal plots of temperature programmed retention times were linear (r=0.999) in carbon number when values for known and previously unidentified LCPA of 4 or 5 double bonds, respectively, were coplotted. Thus, the newly identified fatty acids belong to the n−6 family of fatty acids synthesized from arachidonic acid.
HPLC of plasmalogen‐containing phosphatidylcholine under reverse‐phase or argentation conditions
Authors: Marmer William N. , Foglia Thomas A. , Vail Peter D. 
Published: December 2006

AbstractTwo approaches to the high pressure liquid chromatography (HPLC) isolation of intact plasmalogens were investigated. The first used reversed‐phase HPLC and sought to take advantage of subtle differences in the hydrophobicity of the alk‐1‐enyl chain from the acyl counterpart. On a C‐18 column, bovine heart phosphatidylcholine (PC), which was 47% plasmalogen, was separated into a number of fractions that differed in their molecular species composition. One combination of fractions amounted to a 26% yield of PC enriched to 82% plasmalogen. The second approach sought to take advantage of the uniquely electron‐rich functionality of the plasmalogens, the alk‐1‐enyl ether double bond, and its potential to coordinate with heavy metal ions. Specificially, bovine heart PC was applied to a cation‐exchange type HPLC column in the silver ion mode. Although complete exchange of all the active sites of the column with silver ion led to complete retention of PC, partial activation with silver ion resulted in the separation of the PC into fractions, according to the degree of unsaturation. Plasmalogen‐rich fractions eluted last and remained intact during the process. One combination of these fractions amounted to a 49% yield of PC enriched to 72% plasmalogen. Use of a cation‐exchange system in the mercuric ion mode led to on‐column hydrolysis of the plasmalogen; with palladium ion, the metallic species was stripped from the column by the eluting lipid.