bluuebunny/crossref_metadata_2025_split huggingface dataset:
Further studies of the saturated methyl branched fatty acids ofVernix caseosa lipid
Authors: Nicolaides N. , Apon J. M. B. , Wong David H. 
Published: November 2006

AbstractBy the method of capillary gas chromatography‐mass spectrometry, we have identified 35 monomethyl and 46 dimethyl branched acids in the saturated acids of vernix caseosa lipid with chain lengths ranging from C11 to C18. Many other mono‐, di‐, and trimethyl branched acids have been partially identified. All methyl branches were found to be on the even numbered C‐atoms except for some terminal iso methyl groups. Three types of dimethyl branched acids were found: those with a terminal iso structure, those with a terminal anteiso structure, and those with neither iso nor anteiso structures. The 4‐methyl branch predominated for all types of branched acids. Equivalent chain length data for di‐ and trimethyl branched acids were determined on a Pentasil (nonpolar) wall coated capillary column and checked by calculation from monomethyl branched acid data. Mass spectral identification was performed with and without the aid of a data system. A possible mode of formation of these acids is discussed.
High pressure reverse phase liquid chromatography of fatty acidp‐bromophenacyl esters
Authors: Pel P. T. S. , Kossa W. C. , Ramachandran S. , Henly R. S. 
Published: November 2006

AbstractHigh pressure reverse phase liquid chromatography has been employed to rapidly separate saturated and unsaturated fatty acids as the correspondingp‐bromophenacyl esters. Through the use of a highly efficient C18 reverse phase column packing, it has also been possible to distinguish among geometrical and positional isomers of the unsaturated acids. The use of ultroviolet‐sensitive esters has permitted the detection of low (nanogram range) concentrations of fatty acids. The time required for analysis has been further reduced by employing a novel and rapid method for the preparation of the esters.
Lipid composition of yoshida ascites hepatoma and of livers and blood plasma from host and normal rats
Authors: Ruggieri S. , Fallani A. 
Published: November 2006

AbstractThe lipid composition of Yoshida ascites hepatoma cells was analyzed together with that of ascitic plasma and of livers and blood plasma from host and normal rats. In comparison to normal livers, host livers showed no significant differences in the content of the various lipid classes, but contained a higher percentage of palmitic acid and a lower proportion of arachidonic acid in the major phospholipid classes. In addition, tumor growth induced a marked hypertriglyceridemia in host animals; changes in the concentration of other plasma lipid classes were not statistically significant. The ascitic plasma contained small amounts of lipids mainly constituted by cholesteryl esters and phospholipids. Yoshida hepatoma cells contained less phospholipids in comparison to both host and normal liver, while the increased level of triglycerides and the decrease of free fatty acids were not statistically significant. Hepatoma cells showed appreciable amounts of ether‐linked lipids associated in part to neutral lipids (as glyceryl ether diesters) and, in part, to ethanolamine and choline phosphoglycerides. The alkyl groups in GEDE as well as in ethanolamine and choline phosphoglycerides were mainly constituted by C16∶0 and C18∶0 followed by C18∶1. The alk‐1‐enyl groups in ethanolamine and choline phosphoglycerides were C16∶0 and C18∶0 with only a minor proportion of C18∶1. In comparison to both host and normal liver, Yoshida hepatoma cells showed significant changes in the fatty acid composition of neutral lipids and phospholipids. Some of the major changes consisted of an increase of monoenoic acids associated with a decrease of arachidonic and docosahexaenoic acids in phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol.
Inhibition of sterologenesis in brain and liver of fetal and suckling rats from dams fed di‐2‐ethylhexyl phthalate plasticizer
Authors: Bell Frank P. , Makowske M. , Schneider D. , Patt C. S. 
Published: November 2006

AbstractThe effect of di‐2‐ethylhexyl phthalate (DEHP) on lipid metabolism was studied in liver and brain from fetal rats taken 3 days before parturition from dams receiving dietary DEHP during gestation. In fetuses from rats receiving 0.5% or 1.0% DEHP in a stock diet, the incorporation of14C‐acetate and labeled mevalonate (3H or14C) into the C27 sterols, C30 sterols, and squalene fractions of brain tissue incubated in vitro was significantly reduced between the confidence limits P<0.05 to P<0.001. When liver from fetuses was incubated with labeled mevalonate, incorporation of label into the C27 sterol and C30 sterol fractions was significantly reduced as well (P<0.02 to P<0.001), whereas incorporation of labeled mevalonate into the squalene fraction was not significantly altered. The incorporation of14C‐acetate into total hepatic lipids of the fetal rats was also studied, and statistically significant reductions in incorporation were observed in the lanosterol fraction (P<0.001), the combined fraction of sterol esters + squalene (P<0.02), and the combined fraction of cholesterol + diglycerides (P<0.01). No significant changes were observed in the incorporation of14C‐acetate into phospholipids, free fatty acids, or triglycerides. In 8‐day old suckling rats delivered from dams fed 0.5% DEHP for the last 16 days of gestation and maintained on the same diet during the nursing period, the incorporation of14C‐mevalonate into hepatic C27 sterols, in vitro, was significantly depressed (P<0.05) whereas in corporation into C30 sterols and squalene was similar to control values. In these same suckling rats, body weights were significantly lower in the control group (21.7 vs. 18.8 g, P<0.01), whereas liver weight as a % of body weight was significantly higher (P<0.01) in rats nursing from the DEHP‐fed dams. The results indicate that the inhibitory effect of dietary DEHP on lipid metabolism in the mature rat is transmitted across the placental barrier to the developing fetus and that the abnormal pattern of lipid metabolism in rats delivered from DEHP‐fed females is only partially restored to normal during the suckling periods.
Linoleic acid absorption in the unaesthetized rat: Mechanism of transport and influence of luminal factors on absorption
Authors: Chow S. L. , Hollander D. 
Published: November 2006

AbstractLinoleic acid intestinal absorption was studied in the unanesthetized rat. At low (21–1260 μM) intraluminal concentrations, absorption took place by facilitated diffusion; while at high (1.26–2.5 mM) concentrations, simple diffusion was the predominant mechanism of transport. At low concentrations (840 μM), the equimolar additions of oleic, linolenic, and arachidonic acids or lecithin inhibited the absorption of linoleic acid. Substitution of potassium for sodium in the buffer solution, substitution of Tween 80 for sodium taurocholate, or decrease in the hydrogen ion concentration all resulted in decreased rate of linoleic acid's absorption. These experiments demonstrate that linoleic acid is absorbed by a concentration‐dependent dual mechanism of transport. The absorption rate is modified by the pH, surfactant type and concentration, the simultaneous presence of other polyunsaturated fatty acids, and the thickness of the unstirred water layer.
Thiobarbituric acid test for detecting lipid peroxides
Authors: Asakawa T. , Matsushita S. 
Published: November 2006

AbstractThe thiobarbituric acid (TBA) test has been used in the field of medical science in recent years to detect lipid peroxides. In this case, it is necessary for hydroperoxides to be decomposed to secondary products during the reaction. When purified methyl linoleate and methyl linolenate monohydro‐peroxides were used as the sample for the TBA test, they did not decompose entirely to secondary products, but did so completely when an iron catalyst (ferrous sulfate) was added. However, the iron catalyst also accelerated the autoxidation of coexisting unsaturated fatty acids. Therefore, the addition of antioxidants was required. Fifteen min of heating was sufficient to complete the reaction. With additions of catalyst and antioxidant to the TBA test, it may be possible to make useful distinctions between hydroperoxides and secondary products of lipid oxidation.
A review of the unique features of HDL apoproteins
Authors: Pownall Henry J. , Morrisett Joel D. , Sparrow James T. , Smith Louis C. , Shepherd James , Jackson Richard L. , Gotto Antonio M. 
Published: November 2006

AbstractThe human plasma high density lipoproteins (HDL) are a heterogeneous ensemble of five proteins associated with both neutral and polar lipids. The sequences of all five proteins are known. ApoA‐I and apoA‐II are the major protein components; apoC‐I, apoC‐II and apoC‐III are the minor protein components. All these apoproteins spontaneously recombine with phospholipids to give stable lipid‐protein complexes and freely exchange between the two major HDL subclasses, HDL2 and HDL3. In addition, ApoC‐I, apoC‐II, and apoC‐III exchange between HDL and very low density lipoproteins. Furthermore, certain HDL apoproteins are activators for plasma enzymes that are important in lipid metabolism. ApoA‐I and apoC‐I activate lecithin/cholesterol acyltransferase; apoC‐II is an activator of lipoprotein lipase. The regions of apoC‐I and apoC‐II that are involved in the activation of these enzymes have been localized with synthetic peptides. Studies of synthetic and native fragments of apoA‐II, apoC‐I, apoC‐II, and apoC‐III as well as model lipid‐binding peptides have identified specific regions with structural features common to lipid‐binding proteins. These special properties, which include helical potential, sequences with a critical amphipathic length, and high hydrophobicity of the nonpolar side of the amphipathic helix, are the determinants of HDL structure and metabolism.
Phospholipid exchange between subcellular organelles of rabbit lung
Authors: Spalding J. W. , Hook G. E. R. 
Published: November 2006

AbstractA soluble protein fraction (PLEP) prepared from rabbit lung can catalyze the exchange of phospholipids between subcellular organelles of the lung and between these subcellular organelles and synthetic liposomes. Phospholipid exchange between microsomes and synthetic liposomes and between mitochondria and synthetic liposomes was stimulated 8‐fold and 2.5‐fold, respectively, in the presence of the protein fraction. Lung exchange protein could also catalyze phospholipid exchange between subcellular organelles of the liver and synthetic liposomes. Phospholipid transfer between microsomes and lamellar bodies of the lung was stimulated 2‐fold by the exchange protein. Both radiolabeled phosphatidylcholine (PC) and phosphatidylinositol (PI) were transferred from32P‐labeled microsomes to lamellar bodies, but the exchange protein exhibited no transfer activity for phosphatidylglycerol (PG) and that for phosphatidylethanolamine (PE) was insignificant compared to the transfer activity for phosphatidylcholine and phosphatidylinositol. While the physiological role of the phospholipid exchange proteins in the lung is unknown, it is possible that they participate in the distribution of the newly synthesized phospholipids from the site of synthesis to lamellar bodies and other membrane compartments of cells.
The metabolic fate of cholesterol‐5α,6α‐epoxide in vivo
Authors: Bowden J. P. , Muschik G. M. , Kawalek J. C. 
Published: November 2006

Abstract[14C] Cholesterol‐5α,6α‐epoxide, administered to mice by either gastric intubation or skin painting, was rapidly and primarily excreted in the feces. Residual amounts of the epoxide and its metabolites were found in a wide variety of organs, and persisted for at least 72 hr. At some sites (principally the liver, the small intestinal contents and the combined stomach/duodenum and their contents), the labeled compound existed in a water‐soluble form which could not be extracted with chloroform/methanol. Treatment of the small intestinal contents with a preparation of β‐glucuronidase/sulfatase produced a marked increase in the amount of organic‐solvent‐extractable cholesterol‐α‐epoxide and other polar metabolites. Unchanged epoxide was found mainly in the feces and the skin at the site of application. On the basis of these results, stool specimens, and not blood samples, should be analyzed to detect the presence of this compound and/or its metabolites in vivo.
Varietal differences in peanut triacylglycerol structure
Authors: Sanders T. H. 
Published: November 2006

AbstractStereospecific analysis of triacylglycerols from six peanut varieties showed diversity in percent fatty acid placement. Distribution of the fatty acids among thesn‐1,‐2 and‐3 positions was clearly nonrandom. The percentages of palmitic and stearic acids, generally very low at thesn‐2 position, were more predominant at thesn‐1 than thesn‐3 position. Long chain fatty acids were located almost exclusively at thesn‐3 position. Thesn‐2 position of all varieties was high in unsaturated fatty acids. Triacyglycerols were sufficiently different to suggest that concentrations of specific triacylglycerol species may vary with variety.
Autoxidation of fatty acid monolayers adsorbed on silica gel. IV. Effects of antioxidants
Authors: Wu Guey‐Shuang , Stein Robert A. , Mead James F. 
Published: November 2006

AbstractInclusion of α‐ or γ‐tocopherol in linoleic acid monolayers deposited on a silica gel surface introduced a definite induction period before the initiation of rapid autoxidation, as measured by the disappearance of linoleic acid. The length of the inducation period was found to be proportional to the amounts of tocopherol incorporated at the concentration range tested, and the protection was generally efficient with little loss of linoleic acid to autoxidation. At the onset of the rapid autoxidation, approximately 12% of the tocopherol remained, and most of this was destroyed after an additional short period. γ‐Tocohperol, at the same concentration, was found to be 1.4 times as effective as the α‐isomer. 3‐(ω‐Carboxynonyl)‐4‐methoxy‐5‐pentylphenol, the synthesis of which is described here, did not introduce a detectable induction period, but rather reduced the overall rate of autoxidation throughout a very long period.
Perinatal development of 3‐hydroxy‐3‐methylglutaryl coenzyme a reductase activity in rat lung, liver and brain
Authors: Ness Gene C. , Miller John P. , Moffler Mary H. , Woods Linda S. , Harris Howard B. 
Published: November 2006

AbstractThe developmental pattern of microsomal 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase (EC 1.1.1.34), which catalyzes the rate‐limiting step of cholesterol biosynthesis, was studied in lung, liver and brain of Sprague‐Dawley rats. Each tissue exhibited a distinet pattern. Reductase activity in the fetal lung reached a peak at 19 days of gestation, which corresponds to the onset of active surfactant production. This observation is consistent with the suggestion that the fetal lung synthesizes all surfactant components including cholesterol. In the liver, reductase activity varied in a reciprocal fashion with serum cholesterol levels. The peak of brain reductase activity occurred at 3 days after birth at the onset of rapid brain growth despite rapidly rising serum cholesterol levels.
The effect of steroids and their solubilizing agents on mycelial growth ofPhytophthora cactorum
Authors: Nes W. David , Patterson Glenn W. , Bean George A. 
Published: November 2006

AbstractMycelia ofPhytophthora cactorum, a fungus unable to synthesize sterols, were incubated with a series of sterols and several common sterol solubilizing agents. Cholesterol, campesterol, and sitosterol promoted growth, while carpesterol, saringosterol, 20 α‐hydroxy cholesterol, coprostanol, and 5α‐cholestane inhibited growth. Cholestanol, epicholestanol, and 5α‐cholestan‐3‐one had no significant effect on growth relative to the sterol‐free control. All steroids were solubilized in ethanol for studying structure‐activity correlations. The added steroids were reisolated from mycelia and their identity confirmed by gas liquid chromatography (GLC) or combined gas liquid chromatography‐mass spectrometry (GLC‐MS). Tween 80 promoted growth, Triton X‐100 inhibited growth, and ethanol had no effect on growth relative to a control.
Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets
Authors: Pitas R. E. , Nelson G. J. , Jaffe R. M. , Mahley R. W. 
Published: November 2006

AbstractThe phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine (PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including increases in the percentages of 18∶1ω9 (oleic acid), 18∶2ω6 (linoleic acid), and 20∶3ω6 (homo‐gamma linolenic acid) and a decrease in the percentage of 20∶4ω6 (arachidonic acid). Addition of safflower oil to the tallow‐cholesterol diet partially reversed these effects. These cholesterol‐induced alterations in fatty acid composition could be due to exchange with plasma lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined.
Evidence for the lipoprotein heterogeneity of human plasma high density lipoproteins isolated by three different procedures
Authors: Suenram A. , McConathy W. J. , Alaupovic P. 
Published: November 2006

AbstractQuantitative electroimmunoassays of apolipoproteins in ultracentrifugally isolated high density lipoproteins (HDL) of normolipidemic subjects showed that A‐I and A‐II are the major (80–85% of total HDL protein) and B, C‐III, E, D and F are the minor protein constituents of this density class. A comparison between the apolipoprotein composition of ultracentrifugally isolated HDL and heparin‐Mn++ supernates showed no significant difference in the levels of A‐I and C‐III. However, the concentration of ApoE in the heparin‐Mn++ supernates was almost twice as high as that in the ultracentrifugally isolated HDL; ApoB was only detectable in trace amounts in the heparin‐Mn++ supernates. To establish whether these apolipoproteins are parts of a single macromolecular complex or form separate, discrete lipoprotein particles, the high density lipoproteins were isolated by three different procedures including ultracentrifugation, heparin‐Mn++ precipitation and agarose column chromatography. The double diffusion analyses of each of these HDL preparations with antisera to A‐I, A‐II, ApoB, C‐III, ApoD, ApoE, and ApoF showed nonidentity reactions between each possible combination of these antisera. The only exception was a reaction of partial identity between antisera to A‐I and A‐II polypeptides indicating the occurrence of two types of lipoprotein particles, a major one (LP‐A) containing both polypeptides and a minor one (LP‐A‐I) containing A‐I as the sole protein constituent. These findings indicate that high density lipoproteins, regardless of the manner of isolation, do not consist of a single macromolecular complex, but represent a mixture of several, discrete lipoprotein families.
Behavior of gangliosides on dialysis
Authors: Ghidoni R. , Sonnino S. , Tettamanti G. 
Published: November 2006

AbstractMixed brain gangliosides or individual ganglioside GM1 were dissolved in one of the following solvents: (a) water, (b) 0.1 M aqueous KC1, or (c) methanol‐aqueous 0.1 M KC1 at concentrations ranging from 10−8 to 10−3 M, and were submitted to dialysis against distilled water for up to 4 days. No significant loss of gangliosides on dialysis was observed when gangliosides were dissolved in water or 0.1 M aqueous KC1, but a loss occurred when the ganglioside solution contained methanol; the loss was greater at the lowest ganglioside concentration. However, losses ceased to occur after 1 day when methanol was removed from the dialysis sac.
Inhibition of cholesterol synthesis in mammary tissue, lung, and kidney following cholesterol feeding in the lactating rat
Authors: Kris‐Etherton P. M. , Frantz I. D. 
Published: November 2006

AbstractPregnant rats were randomly allocated to one of 3 experimental dietary groups: Group 1–15.5% butter, 2% cholesterol, 0.78% sodium cholate purified diet; Group 2‐standard rat diet with the addition of 10% lard and 2% cholesterol, and Group 3‐standard rat diet. Plasma and milk cholesterol at 10 days postpartum were significantly elevated in dams fed exogenous cholesterol. The rat of incorporation of [1‐14C] acetate into digitonin‐precipitable sterols of mammary tissue slices from dams in Group 1 and Group 2 was eight‐fold and two‐fold, respectively, less than controls. Mammary tissue cholesterol was greater in dams fed dietary cholesterol. Thus, our data, for the first time, demonstrate that cholesterol synthesis in lactating rat mammary tissue is suppressed following cholesterol feeding. In a second experiment, the rate of incorporation of [1‐14C] acetate into digitonin‐precipitable sterols in kidney and lung tissue of Group 1 rats was suppressed; however, this response was not as marked as that observed in lactating mammary tissue. The concentration of cholesterol in kidney and lung was greater than controls. These results suggest that extrahepatic inhibition of cholesterol synthesis exists in the rat with a concomitant increase in tissue cholesterol.
Synthesis of phosphatidylcholine and phosphatidylethanolamine at different ages in the rat brain in vitro
Authors: Brunetti Marina , Gaiti Alberto , Porcellati Giuseppe 
Published: November 2006

AbstractThe de novo synthesis of choline and ethanolamine phosphoglycerides in brain microsomes from 18 month‐old male rats was investigated in vitro by using labeled cytidine‐5′‐diphosphate choline and cytidine‐5′‐diphosphate ethanolamine as lipid precursors. The rate of synthesis of the two phospholipid classes was found to be noticeably decreased, as compared to that of adult animals. The addition of exogenous diacyl glycerols to microsomes from ageing rat brain brings the rate of synthesis nearly to the adult levels. The synthesis of choline and ethanolamine phosphoglycerides is not affected in the liver microsomes of ageing rats. The molar distribution of fatty acids in brain microsomal diacyl glycerols of ageing rats is noticeably different from that of adult animals. The content of monoenoic and dienoic species is increased, whereas that of the tetraenoic species is decreased. Base exchange reaction for choline and ethanolamine incorporation into respective phospholipids is not affected in the brain microsomes of the aged rats.
Lipid oxidation products and chick nutritional encephalopathy
Authors: Budowski P. , Bartov I. , Dror Y. , Frankel E. N. 
Published: November 2006

AbstractSafflower oil and its distilled methyl esters were thermally oxidized and fed to young chicks in a vitamin E deficient diet. At a dietary level of 10%, the oxidized lipids caused more severe nutritional encephalopathy (NE) than the unoxidized methyl esters, indicating that factors other than dietary linoleic acid and vitamin E affect the development of NE. A polar lipid extract from oxidized methyl esters accelerated the induction of NE, as did the synthetic methyl esters of keto‐octadecenoic and keto‐octadecadienoic acids. Dicumarol exerted a protective action against NE. The possibility is discussed that conjugated keto‐polyenoic fatty acids, provided by oxidized oils or formed endogenously in vitamin E deficiency, may play a role in causing NE.