bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactions of biological antioxidants: I. Fe(III)‐catalyzed reactions of lipid hydroperoxides with α‐tocopherol
Authors: Gruger E. H. , Tappel A. L. 
Published: November 2006

AbstractRates of α‐tocopherol oxidation were measured for free‐radical reactions produced by Fe(III)‐catalyzed dissociations of hydroperoxides. The kinetics were treated as first‐order in α‐tocopherol. The hydroperoxides were preformed from methyl linoleate, methyl linolenate, ethyl arachidonate, methyl eicosapentaenoate, and a fraction of polyunsaturated fatty esters of menhaden oil. The degree of unsaturation of the lipid hydroperoxides had little effect on the rates of α‐tocopherol oxidation. The rates of oxidation decrease with the concentration of water and increase with the acidity of the media. The pH data suggest a transition from one predominant mechanism to another, which may involve principally acid catalysis. A mechanism for α‐tocopherol oxidation is suggested.
Gas liquid radiochromatography of intact natural triglycerides
Authors: Breckenridge W. C. , Kuksis A. 
Published: November 2006

AbstractGas liquid radiochromatography was successfully applied to the simultaneous analysis of mass and radioactivity of intact standard and natural triglycerides labeled with14C in their fatty acid or glycerol moieties. Quantitative measurements of mass and radioactivity were made with a gas chromatograph equipped with dual glass columns, stream splitters, combustion train, and a proportional gas counter. Under optimum conditions, as little as 500 cpm/peak of tristearin could be detected with a relative error of 10%. At higher counting rates the error was less than 5% and the achieved resolution of radioactivity was only slightly inferior to that of the mass. The counting efficiency of the system was better than 90%. The study showed that the detected radioactivity was proportional to the mass and not the moles of the labeled triglyceride measured in the hydrogen flame ionization detector. Practical application of the system is limited by the need for samples of relatively high specific activity (500–1000 dpm/50 μg/peak).
Activation of long chain fatty acids by subcellular fractions of rat liver: II. Effect of ethylenic bond position on acyl‐CoA formation oftrans‐octadecenoates
Authors: Lippel Kenneth , Gunstone F. D. , Barve J. A. 
Published: November 2006

AbstractThe rates of acyl‐CoA biosynthesis of thetrans Δ4 to Δ15 octadecenoates have been studied using rat liver microsomes and mitochondria as the enzyme(s) source. Acyl‐CoA formation was lowest when the Δ9 isomer was the substrate and increased as the double bond was moved to either end of the fatty acid chain. Maximal activation was observed when the Δ6 and Δ14trans‐octadecenoates were substrates. All‐trans retinoate caused differential inhibition in the activation rates of the varioustrans‐octadecenoate isomers. In contrast, the activation profile relative to double bond position was not altered by changing the incubation temperature, pH, or buffer or by adding fatty acid free albumin to the incubation medium or by aging the enzyme. These results do not support the suggestion that more than one enzyme activates the varioustrans‐octadecenoate positional isomers. Triton X‐100 differentially activated acyl‐CoA biosynthesis of the various isomers resulting in a uniform rate of activation. Release of the isomers from the detergent micelle is suggested to be rate‐limiting under these conditions.
Enhancement of liver microsomal acyl CoA‐lysophospholipid acyltransferase activity in pyridoxine‐deficient rats
Authors: Zehaluk C. M. , Walker B. L. 
Published: November 2006

AbstractIn rats deficient in pyridoxine and essential fatty acids, liver phospholipids contained less arachidonic acid and more oleic and eicosatrienoic acids than those from animals only deficient in essential fatty acids. This pattern persisted after the animals were supplemented with linoleate for 6 days. Liver oleyl and arachidonyl CoA‐lysophospholipid acyltransferase activities were significantly higher in pyridoxine‐deficient animals. Supplementation with linoleate for 6 days resulted in a marked increase in arachidonyl CoA‐acyltransferase activity in pyridoxine‐deficient rats but a relatively small increase in the supplemented animals. Differences in fatty acid composition between pyridoxine‐deficient and supplemented rats can not be ascribed to lower liver transacylase activity in the deficient animals.
Effects of ethanol on membrane lipids III. Quantitative changes in lipid and fatty acid composition of nonpolar and polar lipids of mouse total liver, mitochondria and microsomes following ethanol feeding
Authors: Miceli Joseph N. , Ferrell William J. 
Published: November 2006

AbstractThe effects of ethanol on the total, nonpolar, and polar lipids of whole liver, mitochondria, and microsomes have been evaluated. Differences in the fatty acid composition of various lipid subclasses have been compared in control and ethanol treated mice. On the whole polyunsaturated fatty acids, especially arachidonic (20∶4) and docosahexaenoic (22∶6), were found to decrease. The significance of an enzymatic mechanism vs. a peroxidative mechanism to explain the results is discussed. Decreases also were observed in the ratios of arachidonate/linoleate following ethanol feeding. These changes are thought to be associated with decreases in the activity of the chain elongation‐desaturation system.
Biosynthesis of phospholipids in subcellular particles from cultured cells of human tissue
Authors: Tsao Shuang‐Shine , Cornatzer W. E. 
Published: November 2006

AbstractA time study of the incorporation of32Pi into the phospholipids of HeLa, KB, human heart, and liver tissue‐culture cell lines has been carried out. The incorporation of32Pi at various time‐intervals into the phospholipids of nuclei, mitochondria, and microsomes of HeLa and KB cells was investigated. The labeling of the isotope into the phospholipids was divided into three groups.The first had two components: phosphatidyl inositol and polyglycerol phosphatides, which showed the greatest incorporation of the isotope as demonstrated in the specific activity values and the percentage of total radioactivity after 15 to 30 minutes of incubation. A second group was composed of the major phospholipids of all tissue‐culture cell lines studied, phosphatidyl choline, and phosphatidyl ethanolamine. At first, there was a delayed labeling of these phospholipids; however, after one hour of incubation, a rapid increase was shown in the incorporation of32Pi. A third group of lipids containing sphingomyelin and phosphatidyl serine demonstrated low specific activity values.The phospholipids of the subcellular fractions, nuclei, mitochondria, and microsomes, had a high degree of incorporation of the isotope into the individual phospholipids and probably represented an active process in the membranes of these cellular units or a renewal of the biological membrane structures.
I. Synthesis ofsn‐glycerol‐cyclic‐phosphodiester isomers
Authors: Buchnea Dmytro 
Published: November 2006

AbstractA procudure for the synthesis of stereochemically puresn‐glycerol‐cyclic‐phosphodiesters has been developed. The process involves the following sequence of reactions: benzyl‐sn‐glycerol→benzyl‐sn‐glycerol‐cyclic(phenyl)‐phosphodiester→sn‐glycerol‐cyclic‐phosphodiester. The following isomers have been synthesized:sn‐glycerol‐2,3‐1,2‐, 1,3‐cyclic‐phosphodiesters and the racemic mixturer. The 2,3‐ and 1,2‐cyclic‐phosphodiesters of glycerol are optically active antipodes. They are five‐membered ring asymmetrical compounds, with specific rotations of −1.6°±0.1° and +1.6°±0.1°, respectively. These two enantiomers and their racemate are thick liquids and are unstable; therefore they were converted into Ba(glycerol‐cyclic‐phosphodiester)2 salts, which can be better stored. The six‐membered ringsn‐glycerol‐1,3‐cyclic‐phosphodiester is a crystalline, stable compound. The physical and chemical properties of these cyclic‐phosphodiesters of glycerol are described and their chemical analyses are reported.
Studies in vitro of lipogenesis in rat testicular tissue
Authors: Whorton A. R. , Coniglio J. G. 
Published: November 2006

AbstractTesticular tissue was shown to contain the full complement of enzymes required for de novo synthesis of fatty acids. The enzymes capable of snythesizing palmitic acid from citrate, acetate, or acetyl CoA were found to be present in the soluble (cytoplasmic) fraction. These included fatty acid synthetase, acetyl CoA carboxylase, citrate‐cleavage enzyme, malic enzyme, glucose‐6‐phosphate dehydrogenase, and 6‐phosphogluconate dehydrogenase. Optimal conditions for assaying activities of fatty acid synthetase and acetyl CoA carboxylase in the soluble fraction from rat testes were established, and the activities of these two enzymes were determined to be 0.54±0.1 and 0.030±0.002 (nmoles of substrate incorporated into fatty acid per min per mg of soluble fraction protein), respectively. The activities of citrate‐cleavage enzyme, malic enzyme, and the glucose‐6‐phosphate dehydrogenase/6‐phosphogluconate dehydrogenase pair were also measured. The activities were 6.0±0.7, 34.9±4.2, and 29.9±9.3 nmoles/min/mg, respectively.
Intestinal lipid absorption: Evidence for an intrinsic defect of chylomicron secretion by normal rat distal intestine
Authors: Sabesin S. M. , Holt P. R. , Clark S. B. 
Published: November 2006

AbstractIntracellular triglyceride accumulation and delayed chylomicron secretion were demonstrated in distal but not in proximal rat intestine following prolonged steady state fat absorption. After 1 and 4 hr of intraduodenal triolein infusion, the mucosal triglyceride content in distal intestinal segments was greatly increased compared with proximal segments. Electron microscopy at each time interval disclosed greater quantities of lipid droplets within the distal cells and these were much larger than the intracellular droplets in the proximal cells, some attaining an enormous size (9000 mμ). When proximal and distal cells were compared at intervals after cessation of a 4 hr triolein infusion, the differences in intracellular lipid accumulation were also evident because, even after 6 hr the distal cells were still filled with large droplets, whereas the proximal cells were almost devoid of fat. These results indicate a basic cellular difference between proximal and distal intestine in the processing of fat and, in contrast to current concepts, suggest that defective chylomicron secretion is not necessarily associated with limited B‐apoprotein availability.
Elongation and desaturation of dietary fatty acids in turbotScophthalmus maximus L., and rainbow trout,Salmo gairdnerii rich
Authors: Owen J. M. , Adron J. W. , Middleton C. , Cowey C. B. 
Published: November 2006

AbstractTurbot and rainbow trout, which had previously received diets free of fat, were fed [1‐14C] fatty acids. The distribution of radioactivity in the tissue fatty acids was examined 6 days later. In rainbow trout fed [1‐14C] 18∶3ω3, 70% of the radioactivity was present in 22∶6ω3 fatty acid. In contrast, turbot fed [1‐14C] 18∶1ω9, 18∶2ω6, or 18∶3ω3 converted only small amounts of labeled fatty acids (3–15%) into fatty acids of longer chain length. The major product of the limited modification found in turbot was the dietary acid elongated by 2 carbon atoms.
Hepatic lipid metabolism in experimental diabetes: III. Synthesis and utilization of triglycerides
Authors: Van Harken Donald R. , Brown Thomas O. , Heimberg Murray 
Published: November 2006

AbstractLivers removed from normal rats, from alloxan diabetic rats maintained on insulin for two weeks (ADI+), and from insulin‐treated diabetic rats from which insulin had been withdrawn two days before use (AD) were perfused in vitro with 120 mg (468 μmoles) palmitic acid‐1‐C14. Under these conditions, output of TG (triglyceride) was depressed in livers from ADI+ rats and was negligible with livers from AD animals. The total incorporation of C14 into perfusate TG paralleled the chemical measurments of TG output. The concentration of hepatic TG increased during perfusion of livers from normal or ADI+ rats but decreased during perfusion of livers from AD animals.A load of 120 mg of palmitic acid/3 hr was inadequate to maintain net accumulation of TG in livers from AD rats; furthermore it is implicit in this observation that the total load of NEFA (nonesterified fatty acid) perfusing livers from AD rats must be increased considerably to obtain a fatty liver. The total incorporation of C14 into hepatic TG and the specific activity of hepatic TG were depressed during perfusion of livers from AD rats. The production of ketone bodies by livers from AD animals was about five times the normal rates; the output of ketone bodies did not differ from results of other experiments (1) in which the load of palmitic acid added to the medium was varied from 0–80 mg. These observations were discussed with reference to mechanisms for ketogenesis and fatty liver in alloxan diabetes.
Biosynthesis of polyunsaturated fatty acids in the developing brain: I. Metabolic transformations of intracranially administered 1‐14C linolenic acid
Authors: Dhopeshwarkar Govind A. , Subramanian Carole 
Published: November 2006

AbstractThirteen‐day old rats were given intracranial injections of 1‐14C linolenic acid (allcis 9,12,15 octa decatrienoic acid) and were sacrificed after 8 hr. Analysis of brain fatty acids showed that 16∶0, 18∶0, 18∶1, 18∶3, 20∶3, 20∶4, 20∶5, 22∶5, and 22∶6 were labeled. The total fatty acid methyl esters were separated into classes according to degree of unsaturation on a AgNO3∶SiO2 impregnated plate. The bands were scraped off and the eluted fatty acids were first analyzed by radiogas liquid chromatography and then subjected to reductive ozonolysis to determine double bond position. The saturated acids, 16∶0, and 18∶0, as well as the mono‐unsaturated 18∶1, must have been formed from radioactive acetate produced by β oxidation of the injected linolenate. Among the polyunsaturated fatty acids, the triene fraction was characterized and identified as 18∶3 ε3 (Δ9,12,15), the starting material, and 20∶3 ω3 (Δ11,14,17); the tetraene fraction was identified as 20∶4 ω3 (Δ8,11,14,17); the pentaene fraction was identified as 20∶5 ω3 (Δ5,8,11,14,17) and 22∶5 ω3 (Δ7,10,13,16,19); and, finally, the hexaene fraction was shown to be 22∶6 ω3 (Δ4,7,10,13,16,19). The biosynthesis of these ω3 family fatty acids in the brain in situ is discussed.
Structure of bovine milk fat triglycerides: II. Long chain lengths
Authors: Breckenridge W. C. , Kuksis A. 
Published: November 2006

AbstractThe long chain triglycerides of bovine milk fat were isolated by thin layer chromatography, and their chemical structure determined by combined thin layer and gas liquid chromatography, and a stereospecific analysis of a molecular distillate of butteroil of comparable composition. The milk fat fraction (39% of total) contained C8–C20 fatty acids which were distributed among the glycerides of 40–56 acyl carbon atoms in a manner not unlike that found for the same acids in the short chain triglycerides. Although individual triglycerides were not identified, the specific distribution of the fatty acids could best be accounted for by assuming a common pool of long chain 1,2‐diglyceride precursors from which the bulk of both short and long chain triglycerides are synthesized by a stereospecific introduction of C4–C18 fatty acids in position 3 of sn‐glycerol. This hypothesis is compatible with the results of stereospecific analyses of the short and long chain fractions and of the total butteroil. It is supported by the nonrandom distributions demonstrated for the molecular weights of the milk fat triglycerides of different degrees of saturation.
Lung lamellar bodies lack certain key enzymes of phospholipid metabolism
Authors: Garcia Agustina , Sener Stephen F. , Mavis Richard D. 
Published: November 2006

AbstractPalmitoyl CoA‐glycerol‐3‐phosphate acyltransferase, phosphatidate phosphohydrolase, and phospholipase A were assayed in subcellular fractions of rat lung, including lamellar bodies, the putative site of storage and secretion of lung surfactant. The specific activity of each of these enzymes in lamellar bodies was relatively low and could be entirely accounted for by a small contamination of the lamellar bodies fraction by microsomes, as quantitated by the presence of the microsomal marker reduced triphosphopyridine nucleotide cytochromec reductase. These data indicate that lamellar bodies are not the site of synthesis of the lipid component of pulmonary surfactant by pathways involving these enzymes.
Novel interference in thiobarbituric acid assay for lipid peroxidation
Authors: Baumgartner W. A. , Baker N. , Hill V. A. , Wright E. T. 
Published: November 2006

AbstractThe thiobarbituric acid test for lipid peroxidation, when applied to a mixture of acetaldehyde and sucrose, produces a 532 nm aborbing chromogen which is indistinguishable from that formed by malonaldehyde and thiobarbituric acid. Unless special procedures are adopted to correct for this effect, the combined action of acetaldehyde and sucrose interferes seriously with the assay of lipid peroxidation reactions, notably those implicated in alcohol‐induced liver injuries. However, this unusual thiobarbituric acid effect also can be used as a sensitive method for the detection of acetaldehyde.
Cardiac fatty acids in rats fed marine oils
Authors: Teige B. , Beare‐Rogers J. L. 
Published: November 2006

AbstractCardiac fatty acids were studied in young rats fed marine oils for 1 week. When the diet contained 0, 0.5, 1, 2, 4, 8 or 16% by weight of partially hydrogenated oil from Norwegian capelin, the concentration of fatty acids in the cardiac tissue was elevated only at the highest level. The amount of the lipid and the content of docosenoic acid in the heart were less than those observed with 15% partially hydrogenated oil from Canadian herring. Nonhydrogenated Peruvian anchovy oil lacking docosenoic acid produced no change in the amount of fat deposited. The extent of fatty acid accumulation in the heart was related to the dietary C22 acids.
Distribution of cholesteryl esters and other lipid in subcellular fractions of the adrenal gland of the pig
Authors: Cmelik S. H. W. , Ley H. 
Published: November 2006

AbstractTotal lipids from whole pig adrenal glands as well as from their mitochondria, microsomes, liposomes, and cell sap were extracted and fractionated first into neutral lipids and phospholipids. The highest percentage of neutral lipids was found in the cell sap, and the lowest in the microsomal fraction. Neutral lipids were subfractionated into cholesteryl esters, free cholesterol, triglycerides, and free fatty acids. Cholesteryl esters were distributed throughout the liposomes. Free fatty acids represented a substantial part of cell sap lipids, but were present also in the mitochondria, microsomes, and liposomes. Fatty acids of all fractions were analyzed by gas liquid chromatography. Free fatty acids and cholesteryl ester fatty acids from all cellular fractions were similar in composition and were characterized by considerable quantities of linoleic and arachidonic acid. Triglycerides were characterized by an increased percentage of palmitic and a low content of arachidonic acid. Phosphatidyl choline, phosphatidyl ethanolamine, diphosphatidyl glycerol, and sphingomyelin plus phosphatidyl inositol were isolated from the lipids by preparative thin layer chromatography, and their fatty acids analyzed by gas liquid chromatography. Phosphatidyl choline and phosphatidyl ethanolamine from mitochondria, microsomes, and cell sap were very similar in respect of their fatty acid composition. Sphingomyelin plus phosphatidyl inositol was characterized by a high content of C22:2ω6. Diphosphatidyl glycerol was present in mitochondria and in the cell sap.
Rat testicular lipids and dietary isomeric fatty acids in essential fatty acid deficiency
Authors: Jensen Benny 
Published: November 2006

AbstractWeanling rats were fed essential fatty acid‐deficient diets, either completely fat‐free, or with partially hydrogenated fish oil (PHFO, 28 wt %), or with fractions derived from PHFO containing primarily positional isomers oftrans‐eicosenoate (20∶1, 3 wt %) ortrans‐docosenoate (22∶1, 3 wt %). Control animals were fed a peanut oil‐containing diet (28 wt %). After 5 or 15 weeks on the diet, the content of neutral and phosphorus‐containing lipids in the testes was determined. The fatty acid distribution in major lipid classes was analyzed for animals fed the diets for 15 weeks. The testicular stage of maturation or degeneration was assessed by histology. The group fed PHFO exhibited signs of complete testicular degeneration, or lack of maturation, already after 5 weeks, whereas the animals on the diets with the very long chain monoenoic acids suffered severe degenerations only after 15 weeks. In the PHFO‐fed rats, a sharp decline in the concentration of testicular triacylglycerols was observed. In all of the essential fatty acid‐deficient groups, an increase in testicular sphingomyelin was observed. Cholesterol levels were fairly similar among all dietary groups. The total testicular fatty acids of the PHFO‐fed animals contained somewhat more eicosadienoic acid than found in the other groups, and somewhat less (n−9)‐acids. In all EFA‐deficient groups, (n−6)‐acids were lowered, in particular in triacylglycerols and phosphatidyl cholines. The PHFO group did not show a lower (n−6)‐concentration than the other deficient groups, in spite of the more severe symptoms of deficiency. There was no evidence of a major accumulation of long chain isomeric fatty acids in the degenerated testes of the PHFO‐, 20∶1, and 22∶1‐fed groups.
β‐Oxidative cleavage of octanoyl‐and dodecanoyl‐CoA in rat liver cytoplasm
Authors: Kienle M. Galli , Cighetti G. , Santaniello E. , Fiecchi A. , Galli G. 
Published: November 2006

Abstract[12‐14C] Dodecanoyl‐CoA and [8‐14C] octanoyl‐CoA were tested as substrates for shortening the chain by two carbon atoms using both the 105,000 x g soluble fraction and the sonicated mitochondrial fraction of rat liver homogenate as the enzyme source. Both substrates were metabolized by the cytoplasmic enzymes giving rise to the accumulation of intermediates of the β‐oxidation process without formation of two carbon units from the methyl carbon of the acyl residue. A new method is described which allows quantitative estimation of volatile fatty acids formed by β‐oxidation of dodecanoyl‐ and octanoyl‐Coenzyme A.
Maximum lipid reduction by partial lleal bypass: A test of the lipid‐atherosclerosis hypothesis
Authors: Buchwald Henry , Moore Richard B. , Varco Richard L. 
Published: November 2006

AbstractAtherosclerosis is the process responsible for our national epidemic of coronary heart disease. A primary and proven atherosclerotic risk factor is the plasma cholesterol concentration. Yet, proof that a reduction in plasma cholesterol level results in reduction in the incidence or severity of atherosclerosis and atherosclerotic cardiovascular disease stil requires conclusive documentation. The controversial methods of operation and inconclusive results of concluded first and second generation trials are reviewed. These data clearly demonstrate that a definitive test of the lipid hypothesis has not been reported. Evidence is presented to show that the partial ileal bypass operation most nearly fulfills the six features of an “ideal” lipid lowering trial modality: maximum effectiveness (∼50% cholesterol reduction); known mechanism of action; no response “escape” or “rebound”; obligatory effect without patient cooperation; minimal side effects; and relative safety. The basic design and protocol of the National Heart and Lung Institute Program on Surgical Control of the Hyperlipidemias, a secondary intervention trial using a combination of diet therapy and partial ileal bypass surgery, are outlined.