bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chylomicron‐like particles in severe hypertriglyceridemia
Authors: Aviram Michael , Sechter Yael , Brook J. Gerald 
Published: November 2006

AbstractPlasma lipoproteins in a diabetic patient with severe hypertrigly ceridemia and turbid, milky plasma were studied and compared with those found in three primary type V hyperlipoproteinemic and in three normal subjects after a fatty meal. All subjects had normal post‐heparin lipolytic activity. Lipoprotein electrophoresis of the patient's plasma revealed no chylomicron band, and upon short‐time ultracentrifugation the patient's supernatant showed most lipid staining in the pre‐β‐lipoprotein region. This supernatant, which in type V hyperlipoproteinemia as well as in normal subjects after a fatty meal, contains a large proportion of apolipoprotein B‐48 (of intestinal origin) was found in our patient to contain mostly apolipoprotein B‐100 (of liver origin). Upon incubation of normal washed platelets with chylomicrons derived either from type V hyperlipoproteinemic or from normal subjects after a fatty meal, platelet aggregation was decreased, whereas the chylomicron‐like particles from the patient increased platelet activity. It is, thus suggested that the triglyceride‐rich cholesterol‐poor lipoproteins are of liver and not of intestinal origin.
Metabolism and cholestatic effect of 3α‐hydroxy‐7ζ‐methyl‐5β‐cholanoic acid
Authors: Une Mizuho , Mosbach Erwin H. , Cohen Bertram I. , May‐Donath Patricia , McSherry Charles K. 
Published: November 2006

Abstract3α‐Hydroxy‐7ζ‐methyl‐5β‐cholanoic acid (7ζ‐methyl‐LA) was infused intravenously into bile fistula hamsters to investigate its metabolism and effect on the bile flow as compared with lithocholic acid. Following infusion of the labeled bile acids, bile was collected quantitatively to allow measurement of bile flow and bile acid composition. More than 80% of radioactivity was recovered in bile within 4 hr. 7ζ‐Methyl‐LA and lithocholic acid in bile were present as the taurine and glycine conjugates; no free bile acids were detected. 7ζ‐Methyl‐LA was neither hydroxylated nor metabolized to any measurable extent, though lithocholic acid was 7α‐hydroxylated to chenodeoxycholic acid (30–45%).At the infusion rate at which lithocholic acid induced a severe cholestasis (264 nmol/min), 7ζ‐methyl‐LA did not decrease the bile flow. In fact, the infusion of 7ζ‐methyl‐LA produced a mild choleresis under conditions where endogenous bile acid excretion was not changed appreciably compared to control infusions with albumin.It is concluded that 7ζ‐methyl‐LA is not metabolized in the hamster but is conjugated with taurine and glycine, and that the introduction of a methyl group at the 7‐position of lithocholic acid appears to alleviate the cholestatic effect of lithocholic acid in the hamster.
Synthesis of octadecynoic acids and [1‐14C] labeled isomers of octadecenoic acids
Authors: Valicenti A. J. , Pusch F. J. , Holman R. T. 
Published: November 2006

AbstractGeometric and positional isomers of [1‐14C] octadecenoic acids have been synthesized by modifications of published procedures. Positional isomers of octadecynoic acids also have been synthesized to obtain the geometric and positional isomers of the unlabeled octadecenoic acid analogs. The syntheses were accomplished by coupling a haloalkyl compound with a substituted acetylene using n‐butyl lithium in hexamethylphosphoramide. The coupled product, either a 17‐or 18‐carbon acetylenic alcohol, could be semihydrogenated and chain extended to afford a carboxy labeled derivative, could be partially hydrogenated and chain extended to afford a carboxyl labeledcis‐ortrans‐octadecenoic acid in the former case. In the latter case, octadecynoic,cis‐octadecenoic ortrans‐octadecenoic acids could be obtained by the appropriate reactions. The methods used in this study enabled the synthesis of14C‐labeled fatty acids in generally higher yields and by simpler reactions than were previously possible.
The chemistry of lipid peroxidation metabolites: Crosslinking reactions of malondialdehyde
Authors: Nair Vasu , Cooper Curt S. , Vietti David E. , Turner Gregory A. 
Published: November 2006

AbstractMalondialdehyde reacts readily with amino acids to form adducts containing vinylogous amidine linkages. Crosslinking reactions between nucleic acid bases, and amino acids induced by malondialdehyde also have been investigated. The physical data obtained for the adducts provide structural information on the possible mode of crosslinking of proteins and nucleic acids induced by this lipid metabolite.
HPLC measurement of testicular long chain acyl‐CoA synthetases with different substrate specificities
Authors: Grogan W. McLean , Huth Ellen G. 
Published: November 2006

AbstractAcyl‐CoA synthetase activity with various long chain fatty acid substrates was measured in microsomes from rat testes, isolated spermatids and testes of hypophysectomized adult rats, using reversed‐phase high performance liquid chromatography (HPLC). The spectrophotometric HPLC method produced results comparable to those of parallel radiometric assays and was highly specific for acyl‐CoA products. At optimal pH and cofactor concentrations, specific activity from whole testis was similar for 18∶1, 20∶4 and 22∶5 but somewhat lower for 16∶0 over the substrate range 0.01–3.2 mM. Activity from spermatids or from testes of hypophysectomized rats was much lower with 22∶5 than with 18∶1 or 20∶4, whereas activities with 18∶1 and 20∶4 were similar at all substrate concentrations. All substrates exhibited Michaelis‐Menten type saturation kinetics and linear Lineweaver‐Burke plots at lower substrate concentrations but inhibited activity at higher concentrations. Apparent values of KM for 16∶0, 18∶1 and 20∶4 were more than twice that of 22∶5, whereas both observed and calculated maximum velocities were similar for the four fatty acids. Differences in pseudokinetic parameters and differential expression of the testicular acyl‐CoA synthetase activities with different fatty acids suggest the presence of multiple enzymes, at least one of which may be hormonally regulated.
Design of high energy intermediate analogues to study sterol biosynthesis in higher plants
Authors: Rahier Alain , Taton Maryse , Bouvier‐Navé Pierrette , Schmitt Paulette , Benveniste Pierre , Schuber Francis , Narula Acharan S. , Cattel Luigi , Anding Claude , Place Pierre 
Published: November 2006

AbstractSeveral enzymes of plant sterol biosynthesis involve during their catalysis postulated or demonstrated carbocationic high energy intermediates (HEI). The aim of this study was to interfere with plant sterol biosynthesis by means of rationally designed species able to mimic these carbocationic HEI. It has been demonstrated previously that the design of transition state (TS) or HEI analogues could lead to powerful and specific inhibitors of enzymes. We applied this approach to the following target enzymes: 2,3‐epoxy‐2,3‐dihydroqualene cyclase, AdoMet‐cycloartenol‐C‐24‐methyltransferase (AdoMet CMT), cycloeucalenol‐obtusifoliol isomerase (COI) and Δ8‐Δ7‐sterol isomerase. Very potent inhibitors have been obtained in the four cases. As an example, analogues of cycloartenol substituted at C‐25 by a charged heteroatom (N, As, S) have been synthesized and shown to be able to mimic the C‐25 carbocationic HEI involved in the reaction catalyzed by the AdoMet CMT. These compounds were shown to be very potent and specific inhibitors of this enzyme both in vitro (Ki=2.10−8 M, Ki/Km=10−3) and in vivo. The potent inhibitors described are powerful tools to control in vivo the sterol profile of plant cells and therefore to study the structural and functional roles of sterols in cell membranes. Moreover, these compounds constitute leader molecules of a new class of rationally designed inhibitors which could be of value in plant protection.
The role of phytosterols in host plant utilization by cactophilicDrosophila
Authors: Fogleman James C. , Duperret Susann M. , Kircher Henry W. 
Published: November 2006

AbstractThe Cactus‐Drosophila Model System of the Sonoran Desert consists of four endemic species ofDrosophila (D. mojavensis, D. nigrospiracula, D. mettleri andD. pachea) and five species of columnar cacti (agria, organpipe, saguaro, cardón and senita). Extensive collection records indicate that each cactus species has only one species ofDrosophila as the primary resident. The elimination of six of the twenty possible random combinations ofDrosophila species and cactus species can be attributed directly to phytosterols.Drosophila pachea has a strict requirement for Δ7‐sterols such as 7‐cholestenol and 7‐campestenol. Since Δ7‐sterols are found only in senita cactus,D. pachea cannot use agria, organpipe, saguaro or cardón as host plants. The lipid fractions of agria and organpipe are chemically similar and contain high concentrations of several 3β,6α‐dihydroxysterols. Larval viability tests using chemical constitutents of organpipe cactus demonstrate that the sterol diols are toxic toD. nigrospiracula but not to the resident, species,D. mojavensis. Agria and organpipe are therefore unsuitable as host plants forD. nigrospiracula. These results suggest that phytosterols play a major role in determining host plant utilization by cactophilicDrosophila in the Sonoran Desert.
Fatty acid synthesis in vivo and hepatic contribution to whole‐body lipogenic rates in obese zucker rats
Authors: Kannan R. , Learn D. B. , Baker N. , Elovson J. 
Published: November 2006

AbstractWe have re‐examined the claim by Godbole and York, based on the effect of surgical hepatectomy (Diabetologia14∶191, 1978), that liver contributed more than 90% of the newly synthesized FA found in adipose tissue of obese rats at the end of a 1‐hr pulse of3H2O. The amount of newly synthesized FA transported via plasma VLDL from liver to adipose tissue was estimated in lean and obese Zucker rats by determining the effects of Triton WR‐1339, which blocks the uptake of VLDL‐TGFA into tissues. Triton treatment was found not to cause any significant change in the amount of radioactive FA found in subcutaneous/perimetrial fat tissues, carcass or liver in either chow‐fed or high‐glucose, fed‐refed lean or obese rats, although in the fed‐refed dietary state the proportion found in the liver was increased over that in the chow‐fed groups. Furthermore, the amounts of newly made FA which accumulated in the plasma of Triton‐treated, chow‐fed and glucose‐fed refed animals during this period constituted only a few percentages of those found in the adipose tissue of these animals. Thus, in contrast to the claims of Godbole and York, no significant transfer of newly made FA from liver to adipose tissue occurs during a 1‐hr experiment; it follows that the amounts of these FA found in different tissues at the end of that period are valid measurements of their actual lipogenic activities in situ. It is suggested that the Godbole and York results are artifacts of their surgical hepatectomy procedure.
Placental transport oftrans fatty acids in the rat
Authors: Moore Carolyn E. , Dhopeshwarkar Govind A. 
Published: November 2006

AbstractPlacental transport of 9‐trans [1‐14C] octadecenoic (elaidic) and 9‐trans,12‐trans [1‐14C] octadecadienoic (linoelaidic) acids was demonstrated in rats. On the 18th day of gestation, a14C‐labeled albumin complex of elaidic or linoelaidic acid was injected into the jugular vein of pregnant rats. For comparison, 9‐cis [1‐14C] octadecenoic (oleic) or 9‐cis,12‐cis [1‐14C] octadecadienoic (linoleic) acid also was injected into the maternal circulation of rats. All animals were sacrificed 1 hr following injection. Lipid composition and distribution of label were determined in maternal plasma, placental and fetal tissues. Differences in specific activities of plasma, placental and fetal total lipids indicated a decreasing concentration gradient for bothcis andtrans isomers of octadecenoic and octadecadienoic acids. Distribution of radioactivity in various lipid components was determined by thin layer chromatography. Irrespective of the label, the highest percentage of total radioactivity was carried by triglycerides (TG) in maternal plasma (∼60–80%), and was incorporated mainly in phospholipids (PL) of fetal tissues (∼50–60%). A nearly equal distribution of the label was found between PL and TG of placental lipids (∼40%). Radioactivity of fatty acid methyl esters (FAME) determined by radiogas liquid chromatography indicated that after injection of linoelaidate, radioactivity of maternal plasma, placental and fetal tissue FAME was associated only witht,t‐18∶2. Following injection of elaidate, all the radioactivity in placental FAME was associated witht‐18∶1; however, in fetal tissues, the label was distributed between 16∶0 andt‐18∶1. These findings suggest that, in contrast to linoelaidic acid, rat fetal tissues can metabolize elaidic acid via β oxidation to form acetyl CoA and palmitic acid.
Effects of dietarytrans acids on the biosynthesis of arachidonic acid in rat liver microsomes
Authors: Kurata Norimasa , Privett Orville S. 
Published: November 2006

AbstractEffects of dietarytrans acids on the interconversion of linoleic acid was studied using the liver microsomal fraction of rats fed a semipurified diet containing fat supplements of safflower oil (SAFF), hydrogenated coconut oil (HCO) at 5 and 20% levels or a 5% level of a supplement containing 50.3% linolelaidic and 24.3% elaidic acids devoid ofcis,cis‐linoleic acid (TRANS). Growth rate was suppressed to a greater extent with the animals fed the 20% than the 5% level of the HCO‐supplemented diets and still further by the TRANS diet compared to the groups fed the SAFF diets. Food intake was greater in the groups fed the HCO than the SAFF‐supplemented diets, demonstrating the marked effect of an essential fatty acid (EFA) deficiency on feed efficiency. In contrast to an EFA deficiency produced by the HCO supplement, which stimulated the in vitro liver microsomal biosynthesis of arachidonic acid, diets containing the TRANS supplement exacerabated the EFA deficiency and depressed 6‐desaturase activity of the liver microsomal fraction. The liver microsomal fraction of the animals receiving this supplement also was more sensitive to fatty acid inhibition of the desaturation of linoleic acid than those obtained from animals fed either the SAFF or HCO diets. It is suggested that dietarytrans acids alter the physical properties of the 6‐desaturase enzyme system, suppressing its activity, which increases the saturation of the tissue lipids and, in turn, the requirement for EFA or polyunsaturated fatty acids.
The preparation and characterization of the methoxy derivatives of polyunsaturated fatty acids: Stabilized product analogs of lipoxygenase catalysis
Authors: Funk Max O. , Levison Bruce , Keller Maggie B. 
Published: November 2006

AbstractThe products from the action of soybean lipoxygenase on a series of polyunsaturated fatty acids have been converted in 2 steps into the corresponding methoxy derivatives. The product hydroperoxides were reduced in situ to alcohols with sodium borohydride. The ethers were generated by treatment of the alcohols with sodium hydride and methyl iodide in tetrahydrofuran. 13‐Methoxy‐9(Z),11(E)‐octadecadienoic, 15‐methoxy‐11(Z),13(E)‐eicosadienoic and 15‐methoxy‐5(Z),8(Z),11(Z), 13(E)‐eicosatetraenoic acids were thus prepared. The methyl ethers were analyzed and the structures established by high performance liquid chromatography, nuclear magnetic resonance and infrared spectrometry, polarimetry and mass spectroscopy (as methyl esters). The methylation reaction proceeds without molecular rearrangements or racemiziation.
Gangliosides from rat cerebellum: Demonstration of considerable heterogeneity using a new solvent for thin layer chromatography
Authors: Zanetta J‐P. , Vitiello F. , Vincendon G. 
Published: November 2006

AbstractUsing a new solvent (methyl acetate/n‐propanol/chloroform/methanol/0.25% aqueous KCl, 25∶20∶20∶20∶17, v/v) and high performance silica gel thin layer chromatographic plates, all common gangliosides found in brain can be easily separated with 1 hr. This system is reproducible and “tailing” is negligible compared with previous solvents. When such a system is applied to separate the gangliosides found during the development of the rat cerebellum, a considerable heterogeneity is observed. Data are presented (using rechromatography experiments, fractionation on DEAE‐Sephadex, treatment with neuraminidase or alkaline medium and carbohydrate analysis) suggesting that the complex profiles obtained with this chromatographic system are not due to chromatographic artifacts but result from the high resolving power of the system. After separation by ion‐exchange chromatography, 28 gangliosides can be detected.
Heat activation of rat epididymal fat tissue acetyl‐CoA carboxylase is due to dephosphorylation by its endogenous phosphatase
Authors: Krakower Glenn R. , Kim Ki‐Han 
Published: November 2006

AbstractAcetyl‐CoA carboxylase from rat epididymal fat tissue is activated by incubation at 30 C in the absence of citrate or metal ions. This activation is accompanied by a corresponding loss of32P from the labeled enzyme, and it is not blocked by the heat‐stable phosphorylase phosphatase inhibitor proteins from rabbit muscle. We have succeeded in separating an activity which activates and dephosphorylates acetyl‐CoA carboxylase from the carboxylase using polyethylene glycol‐6000. These results suggest that the temperature‐dependent activation of acetyl‐CoA carboxylase in crude or partially purified preparations results from dephosphorylation of the carboxylase by bound phosphatase.
Long‐term effects of high‐fat diets on peroxisomal β‐oxidation in male and female rats
Authors: Thomassen M. S. , Norseth J. , Christiansen E. N. 
Published: November 2006

AbstractIn weanling male rats a 4‐fold increase of heart triacylglycerols was observed after three days on a high‐fat diet containing partially hydrogenated fish oil (PHFO). In female rats this increase was only about 50%. No significant differences were observed between female and male rats in the fatty acid composition of the accumulated lipids.The initial level of peroxisomal β‐oxidation activity was similar in male and female rats in both liver and heart. After three weeks of receiving high‐fat diets, the rats showed a marked increase in peroxisomal β‐oxidation activity with PHFO in the diet and less with soybean oil (SO), confirming previous studies with male rats. Catalase activity was similarly affected in hearts of both sexes.In male rats the levels of peroxisomal β‐oxidation observed after three weeks of feeding on the high‐fat diets were found to be maintained, both in liver and heart, during a feeding period of three months. The response to high‐fat diets in females, however, seems to be further accentuated after three months of feeding, resulting in a capacity of peroxisomal β‐oxidation in liver of about three times that of the male rats when calculated on a total body‐weight basis.
Hypolipidemic activity of the surfactants aminimides, and their effects on lipid metabolism of rodents
Authors: Hall Iris H. , Kabara Jon J. , Matthews Timothy G. 
Published: November 2006

AbstractA series of short chain fatty acid derivatives of aminimides were shown to possess hypolipidemic activity in rats and mice. Most of the agents tested lowered both serum cholesterol and triglyceride levels by at least 30% in mice and were effective in hyperlipidemic induced mice. 1,1‐Dimethyl‐1‐(2‐hydroxypropyl)‐amine mersitimide lowered serum cholesterol levels 41% and serum triglyceride levels 56% at 20 mg/kg/day I.P. after 16 days. The same agent was active orally when administered to rats with a 38% reduction in serum cholesterol and a 52% reduction in serum triglycerides after 14 days. The agents inhibited liver acetyl CoA synthetase, ATP dependent citrate lyase and phosphatidate phosphohydrolase activities in vitro and in vivo. Reduction of cholesterol, triglycerides, neutral lipids and phospholipid levels were noted in the livers of mice treated for 16 days. In rat studies, cholesterol, triglyceride and phospholipid levels were reduced in liver, small intestine and the feces after two weeks' dosing. The cholesterol content was reduced in the very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions but elevated in the high density lipoproteins (HDL). Triglyceride levels were lowered in the VLDL, and neutral lipid levels were reduced in the chylomicron and VLDL fractions.
The distribution and acyl composition of plasmalogens in Guinea pig heart
Authors: Arthur Gilbert , Mock Thomas , Zaborniak Cheryl , Choy Patrick C. 
Published: November 2006

AbstractIn guinea pig heart homogenate, 34% of both choline and ethanolamine phosphoglycerides were in the form of plasmalogens (1‐alkenyl, 2‐acyl glycerophospholipid). Plasmalogens accounted for 39% of the choline phosphoglycerides and 36% of the ethanolamine phosphoglycerides in the mitochondrial fraction. Ethanolamine plasmalogen was the major ethanolamine phosphoglyceride (63%) in the guinea pig heart microsomal fraction. A high arachidonyl content was found in both diacyl and 1‐alkenyl, 2‐acyl glycerophosphoethanolamine. The C‐2 fatty acyl profiles of the diacyl and 1‐alkenyl, 2‐acyl choline phosphoglycerides differed considerably from each other in the homogenate as well as in the subcellular fractions. Significant differences in the C‐2 fatty acyl profiles also were observed in diacyl and 1‐alkenyl, 2‐acyl ethanolamine phosphoglycerides. Such differences suggest there is no direct metabolic relationship between the diacyl glycerophosphocholine (‐ethanolamine) and its plasmalogen analog.
Turnover of phosphocholine and phosphoethanolamine in ether‐phospholipids of krebs II ascite cells
Authors: El Tamer A. , Record M. , Chap H. , Douste‐Blazy L. 
Published: November 2006

AbstractKrebs II ascite cells suspended in Eagle medium were incubated at 37 C for up to 6 hr in the presence of [3H] glycerol or [32P] orthophosphate. After extraction, their lipids were treated with guinea pig phospholipase A1 under conditions where all diacyl‐phospholipids (diacyl‐PL) became hydrolyzed with 55% recovery of lyso‐PL. Using a bidimensional thin layer chromatography (TLC) involving exposure to HCl fumes between the two runs, it then became possible to determine at once the specific radioactivity of the three subclasses (diacyl‐, alkylacyl‐and alkenylacyl) present in choline glycerophospholipids (CGP) and ethanolamineglycerophospholipids (EGP). Compared to diacyl‐PL, a lower de novo synthesis of ether subclasses was evidenced in both CGP and EGP by [3H] glycerol incorporation. Although the same profile was obtained for CGP with [32P] orthophosphate, the three EGP subclasses displayed in this case the same specific radioactivity.These data indicate a higher turnover rate of the polar head group of ether‐EGP compared to either‐CGP. The simple methodology used in the present study might thus prove helpful in developing enzymatic studies dealing with the mechanism of this accelerated renewal.
Induced chemiluminescence of oxidized fatty acids and oils
Authors: Neeman I. , Joseph D. , Biggley W. H. , Seliger H. H. 
Published: November 2006

AbstractThe injection of a strong organic base into milligram quantities of fats and oils dissolved in methylene chloride results in a burst of chemiluminescence whose peak intensity is a function of the previous thermal oxidation history and of the degree of unsaturation of the starting material. The flash of this induced chemiluminescence can be 108 times higher than the steady‐state “spontaneous” chemiluminescence. The kinetics of the induced chemiluminescence are first order in concentration and second order in time. The emission spectrum is broad and extends into the near infrared. A model based on dioxetane chemiluminescence is proposed to explain the observed kinetics.