bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure to demonstrate degradation of [4‐14C] cholesterol to volatile hydrocarbons in rats and in human fecal homogenates
Authors: Levitt M. D. , Hanson R. F. , Bond J. H. , Engel R. R. 
Published: November 2006

AbstractThe inability of previous workers to recover completely the radioactivity from ingested [4‐14C] cholesterol has led to the hypothesis that the colonic flora of some individuals degrade the sterol nucleus to volatile hydrocarbons, particularly CH4. In the present investigation, the production of radioactive volatiles was measured following incubation of [4‐14C] cholesterol with 8 human fecal homogenates or after instillation of the labeled sterol into the cecum of 3 rats housed in a closed rebreathing system. Three of the 8 homogenates and each of the 3 rats produced copious CH4. However, analysis by combustion demonstrated no radioactivity above background in the volatile headspace of the homogenates or the gas space of the closed system housing the rats, indicating that <0.001% of the number 4 carbon of [4‐14C] cholesterol could have been converted to volatile hydrocarbons. This study, therefore, provides no support for the concept that volatile products account for the incomplete recovery of ingested sterols observed in certain subjects. However, this hypothesis can not be excluded entirely until similar results are obtained with subjects who can be shown to degrade cholesterol.
Subnanogram detection oft‐butyldimethylsilyl fatty acid esters by mass fragmentography
Authors: Phillipou G. , Bigham D. A. , Seamark R. F. 
Published: November 2006

AbstractThe mass spectra oft‐butyldimethylsilyl fatty acid esters all display a pronounced (M−C4H9)+ ion. The proportion of the total ionization carried by this fragment, particularly for saturated and mono‐, di‐, and tri‐unsaturated acid derivatives, facilitates their qualitative analysis at the subanogram level by mass fragmentography.
Mass spectrometric localization of methyl branching in fatty acids using acylpyrrolidines
Authors: Andersson Bengt Å. , Holman Ralph T. 
Published: November 2006

AbstractLocalization of a methyl branch in a fatty acid molecule by mass spectrometry is facilitated by using the pyrrolidide rather than the methyl ester. Branched fatty acid methyl esters are converted to pyrrolidides and are then analyzed by gas chromatography and mass spectrometry. The diagnostic fragments indicate position of the methyl branch.
Effects of pentadecan‐2‐one on the growth of cells in culture
Authors: Gilbertson John R. , Fletcher Ronald D. , Kawalek Joseph C. , Demcisak Barbara 
Published: November 2006

AbstractThe effect of inclusion of trace amounts of pentadecan‐2‐one in the incubation medium on the growth of HeLa Cells was evaluated by measuring viable cell counts (cells excluding trypan blue) and incorporation of [14C] leucine into acid precipitable protein. Evidence is presented to show that exposure of the cells to trace amounts of the methyl ketone, 36μg/ml, effectively inhibits cell growth. This inhibition is relieved by simultaneously incubating the cells with a long chain primary alcohol, hexadecan‐1‐ol, but not with the secondary alcohol, pentadecan‐2‐ol. The observation that the ethyl ketone, hexadecan‐3‐one, also inhibits cell growth but at higher concentrations than that observed with pentadecan‐2‐one and that pentadecan‐2‐ol at similar concentrations has no effect on cell growth indicates that, for optimal effect, the keto function must be at the 2‐position. Inhibition of cell growth by pentadecan‐2‐one is not unique to HeLa cells, as suggested by the inhibitory effects of this lipid type on the growth of other malignant cell lines of human origin.
Influence of diet on conversion of14C1‐linolenic acid to docosahexaenoic acid in the rat
Authors: Poovaiah B. P. , Tinoco J. , Lyman R. L. 
Published: November 2006

Abstract14C1‐Linolenic acid was incorporated into lipids of hearts, livers, and carcasses of male rats. We studied the influence of diet composition on extent and distribution of radioactivity. A CHOW diet, a purified, essential fatty acid (EFA)‐deficient diet, a purified control diet, and EFA‐deficient diets with four fatty acid supplements were used. Supplements of 18∶2n−6, 20∶4n−6, 18∶3n−3, and 22∶6n−3 were given as single doses. Radioactivities in liver phosphatidyl ethanolamines (PE), phosphatidyl cholines, and neutral lipids were measured. The distribution of radioactivity among the fatty acids in liver phospholipids was determined. Rats on CHOW diet incorporated far less radioactivity than any other group into lipids of hearts and livers. Most of the activity in livers was recovered as 20∶5n−3 and 22∶6n−3 in all rats. In EFA‐deficient rats, the radioactivity in 22∶6n−3 of liver PE was still increasing 36 hr after14C1‐linolenic acid had been administered. The n−6 supplements (18∶2n−6 and 20∶4n−6) seemed to reduce the conversion of 20∶4n−3 to 20∶5n−3 (desaturation), whereas the n−3 supplements (18∶3n−3 and 22∶6n−3) reduced the conversion of 20∶5n−3 to 22∶5n−3 (elongation). Formation of 22∶6n−3 may be controlled by 22∶6n−3 itself at the elongation of 20∶5n−3 to 22∶5n−3.
Effect of dietary di‐2‐ethylhexyl phthalate on lipid biosynthesis in selected tissues from the rat, in vitro
Authors: Bell Frank P. , Nazir Darius J. 
Published: November 2006

AbstractDi‐2‐ethylhexyl phthalate (DEHP), a plasticizer commonly used in the production of polyvinyl chloride plastics, has become an environmental pollutant. At the present time, the biological significance of phthalates in the environment is unknown. In the present studies, we observed that addition of DEHP to a stock diet of rats resulted in marked effects on incorporation of14C‐acetate into lipid by liver and kidney slices; other organs, such as heart, testes, and aorta were unaffected. Incorporation of14C‐acetate into total lipid of liver (dpm/mg wet wt) from rats, fed 0.5% or 1.0% DEHP for 10 or 18 days, respectively, was decreased to ca. 50% of control values. The decreased incorporation into liver lipid is not attributable to any one lipid fraction, inasmuch as incorporation into the phospholipid, sterol+diglyceride, free fatty acid, triglyceride, and sterol ester+hydrocarbon fractions was decreased 30–70% with respect to controls. In addition, the percent distribution of14C‐acetate among the individual phospholipids was ca. 25% lower in phosphatidyl choline of the DEHP‐fed rats. In rats fed 0.5% DEHP, incorporation of14C‐acetate into total lipid of kidney was similar to control values, but incorporation into the triglyceride and sterol ester+hydrocarbon fraction was decreased 30–40%, whereas incorporation into the sterol+diglyceride fraction was increased 38%. Livers from DEHP‐fed rats were ca. 20% larger than livers from control rats and, at the 0.%% level of DEHP feeding, testes wts were elevated; no significant changes were noted in wts of spleen, heart, aorta, kidney, or body wt gains in rats fed DEHP. These studies emphasize a subtle toxicity of phthalate esters not previously reported and emphasize the need for further biochemical studies to evaluate the effect of phthalates on biological systems.
13C nuclear magnetic resonance spectroscopy of saturated, unsaturated, and oxygenated fatty acid methyl esters
Authors: Tulloch A. P. , Mazurek M. 
Published: November 2006

AbstractChemical shifts have been assigned to all the separate signals in the13C nuclear magnetic resonance spectra of methyl stearate, oleate, and petroselinate by means of the second and third atom isotope effects in spectra of specifically deuterated esters. Spectra of almost all the isomeric hydroxy, acetoxy, and oxo stearates were also measured. From the assignments, the effects of the introduction of a double bond or an oxo, hydroxy, or acetoxy group at different positions on the fatty acid chain on the13C nuclear magnetic resonance spectra were determined. All the isomeric oxo stearates and most of the hydroxy and acetoxy stearates can be distinguished and identified by their13C spectra.
Linoleic acid amides: Effect on cholesteremia and atherosclerosis
Authors: Kritchevsky David , Tepper Shirley A. , Story Jon A. 
Published: November 2006

AbstractSeveral of a series of linoleic acid amides have been reported to inhibit cholesterol‐induced atherosclerosis in rabbits. The three amides which have been studied to the greatest extent are (in order of increasing activity) N‐cyclohexyl linoleamide (AC23), N(α methylbenzyl) linoleamide (AC223), and N[α‐phenyl‐β‐(p‐tolyl) ethyl] linoleamide (AC485). We have found AC223 to inhibit cholesterol absorption in rats and to slightly inhibit exogenous but not endogenous cholesteremia in rabbits. In a fiber‐free diet, AC223 reduces serum cholesterol and liver triglyceride levels. Rats were also fed a basal semipurified diet with and without AC223. Fecal excretion of labeled exogenous (as [14C] cholesterol) or endogenous (as [14C] mevalonolactone) steroid was 44 and 43% higher in drug treated groups. The mechanism of hypocholesteremic action of the linoleamides appears to involve inhibition of cholesterol absorption.
Response to the hypobetalipoproteinemic agent adamantyloxyphenyl piperidine in hyperlipemic rats
Authors: Schurr Paul E. , Day Charles E. 
Published: November 2006

AbstractThe hypobetalipoproteinemic activity of U‐41, 792 (1‐[p‐(1‐adamantyloxy)‐phenyl]‐piperidine) is a marked and selective reduction of heparin precipitating lipoproteins (low density plus very low density lipoproteins) in cholesterol‐cholic acid induced hypercholesterolemic rats. This activity consists of both a reduction in heparin precipitating lipoproteins (HPL) and an increase in high density lipoproteins that are not precipitated by heparin. The increase in high density lipoproteins is routinely noted by decreases in HPL/cholesterol ratios. The pattern of response following single 100 mg/kg doses of U‐41, 792 was determined. After an I.V. dose was administered in a cotton‐seed oil emulsion, serum cholesterol levels were reduced, beginning at 8 hr after administration and persisting for 96 hr. Similar results, though delayed somewhat, were obtained after a single oral dose. Activity was accompanied by increases in weight and cholesterol content of livers. After multiple, daily, oral doses, liver weights, total lipids, and cholesterol contents were reduced. Hypobetalipoproteinemic activity was enhanced by prolonged treatments as demonstrated by analyses of serum obtained weekly throughout 7 wk.
Uptake and metabolism of fatty acids by Soybean suspension cells
Authors: Stumpf P. K. , Weber N. 
Published: November 2006

AbstractSoybean suspension cultures very rapidly take up C16 and C18 fatty acids by a nonspecific, nonenzymic binding of exogeneously added fatty acids to cell walls and by a subsequent transfer into the cell where they are rapidly incorporated into triacylglycerols, phosphatidylcholines, and phosphatidylethanolamines.14C‐Palmitic and14C‐stearic acids follow this sequence but are not desaturated, wherease14C‐oleic and14C‐linoleic acids are transferred more rapidly than the saturated fatty acids and are then further modified. All the data fit a sequence of events by which free oleic acid is first activated to a CoA thioester, and then desaturated to linoleyl‐CoA; both thioesters are then transferred to triacylglycerols, phosphatidylcholine, and phosphatidylethanolamine.
Relationships between base‐exchange reaction and the microsomal phospholipid pool in the rat brain in vitro
Authors: Gaiti Alberto , Brunetti Marina , Woelk Helmut , Porcellati Giuseppe 
Published: November 2006

AbstractThe calcium‐stimulated incorporation of ethanolamine, choline and L‐serine into rat brain microsomal phospholipids has been investigated. The membranes were prelabeled in vitro in their choline or serine phosphoglycerides by base‐exchange and then chasing experiments were done by displacing the lipid‐bound base by ethanolamine, choline, or L‐serine labeled with a different isotope. The results indicate that membrane phosphatidylcholine is presumably a substrate for the exchange with all the three bases, whereas phosphatidylserine exchanges only with ethanolamine and L‐serine but not with choline. A small phospholipid pool (3–7% of the total available pool) is active in the calcium‐dependent exchange with choline, ethanolamine, and L‐serine. When the microsomal membranes are prelabeled in vitro in their phosphatidylcholine moiety through the cytidine‐dependent pathway and then chasing experiments are performed with the three nitrogenous bases, as above, the small phospholipid pool is hardly detectable. In view of these and other results (Gaiti et al., FEBS Letters 49:361 1975), it is suggested that at least two different pools of phosphatidylethanolamine, phosphatidylserine, and phosphatidylcholine might exist in rat brain microsomes.
Phospholipids of human serum
Authors: Williams J. H. , Kuchmak M. , Witter R. F. 
Published: November 2006

AbstractPhospholipids extracted from normal human serum were fractionated into lecithin, lysolecithin, sphingomyelin, phosphatidyl ethanolamine, lysophosphatidyl ethanolamine, phosphatidyl serine, and phosphatidyl inositol. Identification of each was established by thin‐layer chromatography and infrared spectrophotometry. The content of plasmalogen was determined in both lecithin and phosphatidyl ethanolamine fractions. The composition of fatty acids and fatty aldehydes in isolated phospholipids is presented. The degree of unsaturation as reflected in the average content of double bonds per molecule of the fatty acids in phospholipids was: lecithin 1.2, choline plasmalogen 2.1, lysolecithin 0.6, sphingomyelin 0.2, phosphatidyl ethanolamine 2.8, lysophosphatidyl ethanolamine 1.0, phosphatidyl serine 1.0, and phosphatidyl inositol 1.8. Both chlline and ethanolamine plasmalogen aldehydes were predominantly saturated. Molecular weight of each phospholipid was calculated from determined fatty acid and fatty aldehyde compositions; the phosphorus factor for each phospholipid was computed. On a weight percent basis, lecithin, sphingomyelin, and lysolecithin accounted for 95% of the total phospholipids. The ethanolamine‐containing phospholipids accounted for 2.5%, and the remainder was divided among phosphatidyl inositol, choline plasmalogen and phosphatidyl serine.
Influence of temperature on the fatty acid pattern of mosquitofish (Gambusia affinis) and guppies (Lebistes reticulatus)
Authors: Knipprath Werner G. , Mead James F. 
Published: November 2006

AbstractAdult male mosquitofish were adapted to 14–15C and 26–27C water temperature over a 14‐day period and the fatty acids from their total lipids analyzed by gasliquid chromatography.Newly born guppies were raised at the same temperature for eight weeks and analyzed in the same way. Some fish in the warm water group were subjected to a sudden drop in temperature and the changes of the fatty acids studied after two and eight days, and after two and four weeks.In all fish the tendency is toward higher unsaturation at lower temperature, but the acids involved in the change differ with the species of fish. A distinct difference is also obvious when guppies are raised at, or when they are adapted to the low temperature. The diet, too, influences the kind and amount of fatty acid synthesis and deposition.
Absorption of Di‐ and triglycerides by intestinal slices in vitro
Authors: Feldman Elaine Bossak , Borgström Bengt 
Published: November 2006

AbstractThe uptake by hamster intestinal rings of labeled 1,3‐diolein and triolein in bile salt emulsions was studied.About 6% of triolein was taken up from emulsions containing glycerides and fatty acid in 6 mM sodium taurodeoxycholate. Lesser uptake was noted when triolein was emulsified with lecithin, cholesterol and bile salt; lowest uptake (3%) was observed from triolein‐lecithincholesterol emulsions prepared without bile salt.Absorption of 1,3‐diolein from bile salt emulsion was greater and acylation to triglyceride was observed.Diglycerides and triglycerides in small quantity may be absorbed intact from a micellar phase.
Characterization of fatty acids from root and shoot lipids ofCapsicum species
Authors: Lyons James M. , Lippert L. F. 
Published: November 2006

AbstractLipids were extracted from the roots and shoots of four species of theCapsicum (pepper) genus and separated into three fractions: triglycerides; free fatty acids, mono‐ and diglycerides; and phospholipids. The component fatty acids were determined by subjecting the methyl esters to gasliquid chromatography. The predominate fatty acids obtained were palmitic (16∶0) and linoleic (18∶2), with lesser amounts of linolenic (18∶3), stearic (18∶1), and oleic (18∶0). Differences existed in the neutral lipid fractions which might be of value from taxonomic interests; however, the phospholipids from each of the species and plant parts did not differ so greatly. A comparison of the amount of unsaturated fatty acids in the phospholipid fractions indicates that differences exist which might be of value in determining the relative sensitivity of the several species to chilling temperatures.
Long‐chain fatty acids containing ether linkage. I. The antibacterial and fungicidal activities of some new β‐alkyloxypropionic acids and their methyl esters
Authors: Abe Yoshiro 
Published: November 2006

Abstractβ‐Alkoxypropionic acids and their methyl esters were made with alkoxy groups ranging from C4H9O to C18H35O: R‐O‐CH2CH2COOH (CH3). Methyl esters and acids were also made with one and with two oxyethylene groups between the alkoxy group and the propionic acid group: RO (CH2 CH2 O) n‐CH2CH2 COOH(CH3). The compounds were tested againstStaphylococcus aureus and againstPenicillium for growth inhibition. The optimum size of the alkoxy group appears to be R=C12H25. Oxyethylene groups enhanced the activity againstS. aureus, but had relatively little effect againstPenicillium.
Lipid binding in mitochondria from testes of normal and essential fatty acid deficient rats
Authors: Hølmer G. , Tronier B. 
Published: November 2006

AbstractEssential fatty acid (EFA) deficiency in rat causes severe degeneration of spermatogenic tissue. Previously it was shown that the distribution of lipid classes changes very little during tissue degeneration. However it is well known that the fatty acid spectrum in lipids from testicular tissue is altered drastically during EFA deficiency. The molecular binding of lipids in membrane structures might be altered when a larger amount of ω9‐acids is present in the various lipid classes in testes of EFA‐deficient rats. In the present studies comparison was made of the binding of lipids in testicular mitochondrial membranes from rats fed a fat‐free diet or a diet containing 6% peanut oil for 26 weeks. Isolated mitochondria were coated on glass beads, then dried and packed into a column, whereafter the membrane lipids were eluted with solvents with increasing dielectric constants. The differences between the binding of lipid classes in supplemented and EFA‐deficient rats were not pronounced, but a tendency to a weaker binding in the EFA‐deficient rats was observed. However for both groups the various extracts showed marked differences in the distribution of lipid classes concurrent with the change of the eluent. This indicates a different kind of binding in the membrane, not only for different lipid classes, but also within a special lipid class. Thus both phosphatidylcholines (PC) and phosphatidylethanolamines (PE) were found in extracts with quite different dielectric constants. The fatty acid composition of PC and PE in the major fractions eluted with chloroform and ethanol, respectively, was essentially the same. This indicates that the successive release of phospholipids (PL) in these two fractions was not based on fatty acid solubility properties but on variable binding in the membrane structure. The introduction of ω9‐polyenoic fatty acids instead of ω6‐polyenoic fatty acids in the PL of mitochondria membranes from EFA‐deficient rats seems to be the only deviation in the lipid pattern of EFA‐supplemented and EFA‐deficient animals, and might therefore be responsible for the symptons of EFA deficiency.
Fluorescent modification of serum albumin by lipid peroxidation
Authors: Fletcher B. L. , Tappel A. L. 
Published: November 2006

AbstractPeroxidation of fatty acids bound to human serum albumin results in the production of fluorescent chromophores in the protein when it is stored in the liquid, powdered or crystalline state. Peroxidizing polyunsaturated fatty acid esters, and carbonyls derived from peroxidizing lipids react with amino groups of protein to give products that have fluorescence spectra very similar to those observed for stored commercial preparations of serum albumin.
Lipid metabolism ofAgaricus bisporus (Lange) sing.: I. Analysis of sporophore and mycelial lipids
Authors: Holtz R. Barry , Schisler Lee C. 
Published: November 2006

AbstractThe lipid components of four strains ofAgricus bisporus (Lange) Sing., the cultivated mushroom, were analyzed. Both sporophore and mycelial samples were obtained from beds in normal production. A method for obtaining mycelium free of compost was developed. Neutral lipids were separated from polar lipids by silicic acid column chromatography. Each fraction was separated by thin layer chromatography. Fatty acid methyl esters were analyzed by gas liquid chromatography and mass spectrometry. Sporophore extracts contained free sterol, free fatty acid, triglycerides, phosphatidyl choline and phosphatidyl ethanolamine. High amounts of linoleic acid were found in both neutral and polar lipid fractions. Mycelial extracts contained free fatty acids, triglycerides, phosphatidylcholine and phosphatidyl ethanolamine. No free sterol could be detected. Linoleic acid was also present in large amounts.
Chemical reactions at lipid‐gas interfaces: I. Terminal chain elongation of fatty acids
Authors: Johnson C. B. , Wilson A. T. 
Published: November 2006

AbstractReactions of free methyl radicals and monolayers of potassium palmitate and of potassiumn‐heptadecanoate on an aqueous surface yielded straight chain saturated fatty acids containing longer hydrocarbon chains than those of the reactant acids. Similar results were obtained from the reactions of free ethyl radicals and potassium palmitate under similar conditions. The results of this investigation indicate that extension of hydrocarbon chains by free radical addition reactions can be achieved if the growing chains are suitably packed in a monolayer on a surface.
Effect of bovine serum albumin on monoacyl‐ and diacylglycerol 3‐phosphate formation in mitochondrial and microsomal fractions of rabbit hearts
Authors: Zaror‐Behrens Gloria , Joe Kako K. 
Published: November 2006

AbstractThe formation of monoacyl‐ and diacylglycerol 3‐phosphate (P) by rabbit heart mitochondrial and microsomal fractions was studied by varying the concentration of acyl‐CoA and that of bovine serum albumin in the assay system. The two subcellular fractions were prepared by the conventional differential centrifugation technique. The optimal concentration of acyl‐CoA for both mitochondrial and microsomal acylation of glycerol 3‐P was shifted to a higher range of acyl‐CoA concentrations by greater amounts of albumin. A similar shift in the acyl‐CoA concentration‐enzyme activity relationship was observed in the acylation reaction of 1‐palmitoylglycerol 3‐P by the heart microsomes. The addition of albumin increased slightly the rate of diacylglycerol 3‐P accumulation but increased greatly the rate of monoacylglycerol 3‐P accumulation at any concentration of acyl‐CoA; the effect was observed with mitochondrial or microsomal fraction as the crude enzyme source. Moreover, palmitoyl‐CoA and linoleoyl‐CoA served equally well as the acyl donor for the acylation reaction. However, relatively more monoacyl‐ than diacylglycerol 3‐P was accumulated in the assays with rabbit heart mitochondrial fraction in the presence of albumin, whereas more diacylthan monoacyglycerol 3‐P was formed by the microsomal fraction. As a result, the microsomal diacyl: monoacyl‐glycerol 3‐P ratio was invariably greater than the mitochondrial ratio at a given concentration of acyl‐CoA and albumin.