bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipids fromPlasmodium vinckei‐infected erythrocytes and their susceptibility to oxidative damage
Authors: Stocker Roland , Cowden William B. , Tellam Ross L. , Weidemann Maurice J. , Hunt Nicholas H. 
Published: November 2006

AbstractThe constituent lipids of plasma and red blood cells (RBC) from mice late in infection with the malarial parasitePlasmodium vinckei were analyzed and compared with those obtained from uninfected animals. On a dry weight basis, the total extractable lipids of RBC increased three‐fold during infection, while those of the plasma did not change significantly. In general, changes in individual plasma lipid constituents paralleled those found in RBC of infected mice but were of smaller magnitude. While the increase in the total lipids of parasitized RBC was largely attributable to an increase of more than fourfold in total phospholipids, a significant increase in neutral lipids was also observed. Phosphatidylcholine and phosphatidylethanolamine were the major phospholipids present within RBC, and their total and relative concentrations increased as a result of the infection. A parallel increase occurred in the ratio of unsaturated to saturated fatty acids in the parasitized RBC phospholipids. Infection was also associated with decreases in the relative amount of cholesterol present in RBC and in the ratio of cholesterol to phospholipid. Consistent with this, the fluorescence polarization of 1[4‐(trimethylamino)phenyl]‐6‐phenylhexa‐1,3,5‐triene within parasitized RBC plasma membranes was decreased in comparison with its value in noninfected RBC, indicating that malarial infection decreases the “order” of membrane lipids. These modifications, in conjunction with the increased levels of vitamin E and malonyldialdehyde reported elsewhere, are important determinants of the susceptibility of the different membrane compartments within infected RBC to peroxidative damage.
Improved enzymatic hydrolysis of conjugated bile acids
Authors: Highsmith W. Edward , Hyde Paul M. 
Published: November 2006

AbstractThe hydrolysis of conjugated bile acids by cholylglycine hydrolase (EC 3.5.1.24) using the standard procedure for a commercial enzyme preparation was found to be incomplete, as judged by the use of 24‐14C‐taurocholic acid as a tracer. A method is proposed that incorporates the nonionic detergent Triton X‐100 into the reaction mixture to achieve almost complete hydrolysis. It is proposed that the observed enhancement of enzyme activity is due to the formation of micelles by the detergent.
Serum lipid abnormalities in a chemical/viral mouse model for Reye's syndrome
Authors: Murphy M. G. , Archambault‐Schertzer L. , Ackman R. G. , Crocker J. F. S. 
Published: November 2006

AbstractNeonatal mice given nontoxic dermal applications of an industrial surfactant, Toximul MP8 (Tox), and subsequently infected with sublethal doses of mouse‐adapted human Influenza B (Lee) virus (FluB) develop many of the biochemical features of Reye's Syndrome (RS). To determine whether these also include abnormal circulating lipid, we examined serum lipid profiles in the mouse model throughout the treatment course using Iatroscan‐TH10. Following 10 days of exposure to surfactant, serum phospholipid and cholesterol levels were significantly reduced relative to control animals. These reductions were transient; however, four days following virus administration, significant differences in serum lipid were again evident. These abnormalities coincided and correlated with increased animal mortality. Animals that received combined Tox + virus treatment had significant decreases in serum total lipids relative to control animals, a reflection of a reduction in all lipid classes, including phospholipid, cholesterol, neutral glycerides (triglycerides plus diglycerides) and free fatty acids. Phospholipid (specifically phosphatidylcholine and lysophosphatidylcholine) and free fatty acid levels in the Tox + virus group were also significantly lower than those in animals that received virus alone. This study has demonstrated that suckling mice given chemical/viral treatment have the serum hypopanlipidemia but not the freefattyacidemia that are characteristic of RS.
Autoxidation of cholesterol in tallows heated under deep frying conditions: Evaluation of oxysterols by GLC and TLC‐FID
Authors: Bascoul J. , Domergue N. , Olle M. , de Paulet A. Crastes 
Published: November 2006

AbstractThe products of cholesterol autoxidation (oxysterols) in heated animal food fat were determined qualitatively and quantitatively to evaluate their toxicity and those of the foods in which they occur. Samples of beef tallow were taken from deep‐fat fryers while they were in use. The oxysterols were identified and assayed by gas liquid chromatography and thin layer chromatography on Chromarods with flame ionization detection (TLC‐FID). The two methods were compared and the TLC‐FID method was found more convenient for a rapid estimation of autoxidation. Of the original cholesterol, 25% was destroyed during cooking and partly transformed into 3β‐5‐6β‐trihydroxy‐5α‐cholestane, 7α‐hydroxy‐, 7β‐hydroxy‐, 7‐oxo‐cholesterol, 7‐oxo‐cholesta‐3‐5‐diene and cholesterol epoxides. Certain other oxysterols were present in smaller quantities.
Mechanism of anesthesia: The potency of four derivatives of octane corresponds to their hydrogen bonding capacity
Authors: Brockerhoff Hans , Brockerhoff Susan , Box Lynda L. 
Published: November 2006

AbstractThe anesthetic potency of four derivatives of n‐octane was measured by tadpole righting reflex and expressed as effective millimolar concentration of drug in membrane, ED50M. Potency diminished (ED50 increased) in this order: 1‐octanol, ED50M=5.5; 1‐(2‐methoxyethoxy)octane, ED50M=28; 1‐methoxyoctane, ED50M=61; and 1‐cholorooctane, ED50M>100. Since the aliphatic chain length was kept constant it is concluded that the differences in anesthetic potency are a consequence of the differences in head group structure. This results is predicted by a theory (Lipids 17, 1001–1003 [1982]) which holds that anesthesia is the result of a drug‐induced restructuring of the hydrogen belts, those strata of the membrane that contain the hydrogen bond receiving and donating CO and OH group of the membrane lipids and the adjoining proteins. The Meyer‐Overton rule for anesthetics should be modified: chemical induce anesthesia at equimolar in‐membrane concentration provided their hydrogen‐bonding parts are identical.
Effect of pyridoxine deficiency on phospholipid methylation in rat liver microsomes
Authors: Loo George , Smith John T. 
Published: November 2006

AbstractThe effect of altered methionine metabolism during pyridoxine deficiency on the activity of phosphatidyl‐ethanolamine methyltransferase (EC 2.1.1.17) and the levels of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) has been evaluated in rat liver microsomes. Animals fed a pyridoxine‐deficient diet for 7 wk displayed a fivefold increase in the hepatic tissue level of S‐adenosylhomocysteine when compared to either control or pair‐fed animal counterparts. When PE methyltransferase was assayed in vitro, a significant increase in specific activity was observed using enzyme preparations from either pair‐fed or pyridoxine‐deficient rats. On the other hand, phospholipid levels did not conform to the measured enzyme activity. The level of PC in microsomes from either pyridoxine‐deficient or pair‐fed animal groups was significantly lower than that determined for the control group of rodents. However, the level of PC was noticeably lower in microsomes from pyridoxine‐deficient animals than that from pair‐fed animals, which received 45% of the feed intake of the control animals. In addition, the level of PE in microsomes from pair‐fed and pyridoxine‐deficient animals was significantly higher than that analyzed from the control animals, further confirming decreased methylation of substrate to product. It is concluded that pyridoxine deficiency may alter the methylation of phospholipid in the endoplasmic reticulum above and beyond that produced by feed restriction alone.
Plasma membrane lipids of bovine adrenal chromaffin cells
Authors: Malviya A. N. , Gabellec M. M. , Rebel G. 
Published: November 2006

AbstractThe lipid composition of plasma membranes isolated from bovine adrenal chromaffin cells has been determined. Choline and ethanolamine phosphatides were predominant; the level of lyso compounds was very low. The amount of cholesterol and the cholesterol/phospholipid molar ratio was low compared to those of the other subcellular fractions of chromaffin cells. A complex pattern of neutral glycolipids was observed in contrast to that of gangliosides.
Diurnal rhythm of HMG CoA reductase activity in canine intestine is independent of luminal contents
Authors: Gebhard Roger L. , Sievert Chester E. , Prigge William F. 
Published: November 2006

AbstractActivity of the enzyme 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase (EC 1.1.1.34) measured in isolated segments of canine intestinal mucosa showed a distinct diurnal rhythm. Total activity changed over a twofold range with a peak occurring during midday, shortly after feeding. Since the isolated segments had no contact with luminal contents, the rhythm was not directly related to food components or bile salts. Humoral or neural influences must mediate the rhythm. The diurnal rhythm persisted for at least 3–5 mo, but was lost by 10 mo following formation of the isolated segment, possibly because of mucosal involution.
Age‐related changes in the lipid compositions of rat and human tissues
Authors: Kalén Anders , Appelkvist Eeva‐Liisa , Dallner Gustav 
Published: November 2006

AbstractThe levels of cholesterol, ubiquinone, dolichol, dolichyl‐P, and total phospholipids in human lung, heart, spleen, liver, kidney, pancreas, and adrenal from individuals from one‐day‐old to 81 years of age were investigated and compared with the corresponding organs from 2 to 300 day‐old rats. The amount of cholesterol in human tissues did not change significantly during aging, but the level of this lipid in the rat was moderately elevated in the organs of the oldest animals. In human pancreas and adrenal the ubiquinone content was highest at one year of age, whereas in other organs the corresponding peak value was at 20 years of age, and was followed by a continuous decrease upon further aging. A similar pattern was observed in the rats, with the highest concentration of ubiquinone being observed at 30 days of age. Dolichol levels in human tissues increase with aging, but they increase to very different extents. In the lungs this increase is seven‐fold, and in the pancreas it is 150‐fold. The elevation in the dolichol contents of rat tissues ranges from 20 to 30‐fold in our material. In contrast, the levels of the phosphorylated derivative of dolichol increased to a more limited extent, i.e., 2 to 6‐fold in human tissues and even less in the rat. These results demonstrate that the levels of a number of lipids in human and rat organs are modified in a characteristic manner during the life‐span. This is in contrast to phospholipids, which constitute the bulk of the cellular lipid mass.
Molecular species analysis of phosphoglycerides from the ripe roes of cod (Gadus morhua)
Authors: Bell M. V. 
Published: November 2006

AbstractMolecular species of the 3,5‐dinitrobenzoyl derivatives of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) were quantitated by UV detection at 254 nm after reversed‐phase HPLC using solvent systems modified from Takamuraet al. (Lipids 21, 356–361, 1986). Three isocratic solvent systems were used and a total of 39 different molecular species detected. Four species, 16∶0/20∶5, 18∶1/20∶5, 16∶0/22∶6 and 18∶1/22∶6 contributed 67.2% and 61.8% of PC and PE respectively but only 23.0% of PI. In PI the most important species was 18∶0/20∶4 at 36.7% but this species only constituted 0.7% in each of PC and PE. Small amounts of dipolyunsaturated species were also found in PC and PE.
The suppression of eicosanoid synthesis by peritoneal macrophages is influenced by the ratio of dietary docosahexaenoic acid to linoleic acid
Authors: Lokesh Belur R. , Black J. Mark , Kinsella John E. 
Published: November 2006

AbstractThe efficacy of docosahexaenoic acid (DHA) in suppressing eicosanoic synthesis by peritoneal macrophagesin vivo was influenced by the relative amount of dietary DHA when linoleic acid (LA) was held constant. Increasing DHA from 0 to 37% of the fatty acids in diets containing 10 weight % fat (of which LA was 40%) caused an eleven‐fold increase in the DHA content of macrophages. Limited retroconversion of DHA to eicosapentaenoic acid was observed. Macrophages in animals consuming DHA synthesized significantly lower amounts of leukotriene E4, prostaglandin E2 and 6‐keto prostaglandin F1αin vivo upon stimulation with zymosan. The maximum inhibition of eicosanoid synthesis was observed when the dietary DHA/LA ratio was 0.16 and no further inhibition occurred when the ratio was increased up to 0.81.
Effects of omega‐3 fatty acids on vascular smooth muscle cells: Reduction in arachidonic acid incorporation into inositol phospholipids
Authors: Yerram Nagender R. , Spector Arthur A. 
Published: November 2006

AbstractA rapid increase in arachidonic acid incorporation into phosphatidylinositol (PI) occurred following exposure of cultured porcine pulmonary artery smooth muscle cells to calcium ionophore A23187. This response was specific for PI and phosphatidic acid; none of the other phosphoglycerides showed any increase in arachidonic acid incorporation. The incorporation of [3H]inositol also was increased, indicating that complete synthesis of PI rather than only fatty acylation occurred in response to the ionophore. The presence of omega‐3 fatty acids, especially eicosapentaenoic acid (EPA), reduced arachidonic acid but not inositol incorporation into PI. Stimulated incorporation of EPA also occurred under these conditions, suggesting that EPA replaces arachidonic acid in the newly synthesized pool of PI. Although much less arachidonic acid was incorporated into the polyphosphoinositides following exposure to the ionophore, arachidonic acid incorporation into these phosphorylated derivatives also decreased when EPA was present. These findings suggest that when omega‐3 fatty acids are available, less arachidonic acid is channeled into the inositol phospholipids of activated smooth muscle cells because of replacement by EPA. This may represent a mechanism whereby omega‐3 fatty acids, especially EPA, can accumulate in the metabolically active pools of inositol phospholipids and thereby possibly influence the properties or responsiveness of vascular smooth muscle.
Autoxidation of methyl linoleate initiated by the ozonide of allylbenzene
Authors: Ewing James C. , Cosgrove John P. , Giamalva David H. , Church Daniel F. , Pryor William A. 
Published: November 2006

AbstractAllylbenzene ozonide (ABO), a model for polyunsaturated fatty acid (PUFA) ozonides, initiates the autoxidation of methyl linoleate (18∶2 ME) at 37°C under 760 torr of oxygen. This process is inhibited by d‐α‐tocopherol (α‐T) and 2,6‐di‐ert‐butyl‐4‐methylphenol (BHT). The autoxidation was followed by the appearance of conjugated diene (CD), as well as by oxygen‐uptake. The rates of autoxidation are proportional to the square root of ABO concentration, implying that the usual free radical autoxidation rate law is obeyed. Activation parameters for the thermal decomposition of ABO were determined under N2 in the presence of radical scavengers and found to be Ea=28.2 ±0.3 kcal mol−1 and log A=13.6±0.2; kd (37°C) is calculated to be (5.1±0.3)×10−7 sec−1. Autoxidation data are also reported for ozonides of 18∶2 ME and methyl oleate (18∶1 ME).
Gas chromatographic analysis of intact steryl esters in wild typeSaccharomyces cerevisiae and in an ester accumulating mutant
Authors: Fenner Gregeory P. , Parks Leo W. 
Published: November 2006

AbstractThe steryl ester faction from wild type and mutant strains of the yeastSaccharomyces cerevisiae was analyzed without saponification by a non‐polar capillary gas chromatographic column. When expressed as μg ester/mg dry wt, the total ester fraction remained constant or declined slightly from log to stationary phase in the wild type. In the mutant the decrease was more dramatic. No individual ergosteryl ester species was dominant throughout the culture cycle in the wild type. A compound tentatively identified as zymosteryl palmitate was the most prevalent ester in wild type log phase cells, ergosta‐5,7‐dienyl palmitate and ergosta‐5,7‐dienyl palmitoleate were the major esters in stationary cells. In the mutant strain, ergosteryl esters of palmitate, palmitoleate, oleate, and stearate were the major ester components throughout the culture cycle. Like the wild type, however, the mutant showed an increase in the proportion of ergosta‐5,7‐dienyl esters in the stationary phase of the culture cycle. The data did not indicate a sterol/fatty acid specificity during the culture cycle.
Novel branched‐chain fatty acids in certain fish oils
Authors: Ratnayake W. M. N. , Olsson B. , Ackman R. G. 
Published: November 2006

AbstractMethyl‐branched fatty acids, which are usually minor components (≤0.1%) in fish oils, were concentrated in the non‐urea‐complexing fraction along with polyunsaturated fatty acids during the enrichment of omega‐3 fatty acids from certain fish oils via the urea complexation process. The methyl‐branched fatty acids in the omega‐3 polyunsaturated fatty acid concentrates, which were prepared from three fish body oils, were characterized by gas chromatography and gas chromatography/mass spectrometry. Among the major branched‐chain fatty acids expected and identified were the known isoprenoid acids—mainly 4,8,12‐trimethyltridecanoic, pristanic, and phytanic—and the well‐known iso and anteiso structures. Two novel phytol‐derived multimethyl‐branched fatty acids, 2,2,6,10,14‐pentamethylpentadecanoic and 2,3,7,11,15‐pentamethylhexadecanoic, were identified in redfish (Sebastes sp.) oil. These two fatty acids were absent in oils from menhaden (Brevoortia tyrannus) and Pacific salmon (mixed, but mostly from sockeye,Oncorhynchus nerka). The major branched‐chain fatty acid in the salmon oil, 7‐methyl‐7‐hexadecenoic acid, was also present to a moderate extent in menhaden oil. A novel vicinal dimethyl‐branched fatty acid, 7,8‐dimethyl‐7‐hexadecenoic was detected in all of the fish oils examined, but was most important in the salmon oil. Three monomethyl‐branched fatty acids, 11‐methyltetradecanoic acid, and 11‐ and 13‐methylhexadecanoic, hitherto undescribed in fish lipids, were also detected in salmon, redfish and menhaden oils.
HPLC method for quantitation of cholesterol and four of its major oxidation products in muscle and liver tissues
Authors: Csallany A. Saari , Kindom S. E. , Addis P. B. , Lee Joo‐Hee 
Published: November 2006

AbstractA fast, sensitive, high performance liquid chromatographic method was developed for the quantitation of cholesterol and four of its major oxidation products: 3β‐hydroxycholest‐5‐en‐7‐one (7‐ketocholesterol), cholest‐5‐ene‐3β, 7α‐diol (7α‐hydroxycholesterol), cholest‐5‐ene‐3β,7β‐diol (7β‐hydroxycholesterol), and cholest‐5‐ene‐3β,25‐diol (25‐hydroxycholesterol). In this procedure 2∶1 chloroform:methanol (v/v) extracts of tissue homogenate were combined, dried over anhydrous Na2SO4, filtered, evaporated to dryness under N2 and dissolved with a mobile phase of either 97∶3 or 93∶7 hexane:isopropanol (v/v). After membrane filtration and without further purification, aliquots were directly injected onto a 10‐μm pore size, 30×0.39 cm μ‐Porasil normal phase column. The separation of cholesterol and its oxidation products was monitored by a UV detector at 206 and 233 nm. This method was successfully applied to pork muscle as well as mouse liver tissues and was able to detect cholesterol oxidation products (COP) in the ppm range. The identity of the COP was confirmed by mass spectroscopy.
HPLC analysis of desmosterol, 7‐dehydrocholesterol, and cholesterol
Authors: Goh Edward H. , Colles Scott M. , Otte Kimberly D. 
Published: November 2006

AbstractA simple and sensitive method to analyzed mixtures of desmosterol, 7‐dehydrocholesterol and cholesterol is described. The method involves the oxidative conversion of the sterols with cholesterol oxidase, followed by high performance liquid chromatographic (HPLC) analysis. A C18 reversed phase column (3 μm, 75×4.6 mm) and a mixture of methanol and acetonitrile (1∶1, v/v) at a rate of 1 ml/min are used to separate the sterols. The eluted sterols are quantified by measuring UV absoprtion at 240 nm. As little as 10 pmoles of sterol can be quantified under these conditions.
Identification of cholesta‐7,24‐dien‐3β‐ol and desmosterol in hamster cauda epididymal spermatozoa
Authors: Awano M. , Kawaguchi A. , Morisaki M. , Mohri H. 
Published: November 2006

AbstractThe sterol composition of hamster cauda epididymal spermatozoa was remarkably different from that of several other mammalian spermatozoa. Desmosterol and cholesta‐7,24‐dien‐3β‐ol account for as much as 90% of the total sterols. Cholesterol and desmosterol are the major components of mouse cauda epididymal spermatozoa, and rabbit, boar and bull ejaculated spermatozoa. Cholesta‐7,24‐dien‐3β‐ol was not detected. Furthermore, cholesterol was the main sterol in hamster caput epididymal spermatozoa, while only a trace amount of desmosterol was detected and cholesta‐7,24‐dien‐3β‐ol was hardly detected at all. The sterol content of cauda and caput epididymal spermatozoa was 0.17±0.05 μmol/108 spermatozoa. During maturation, the desmosterol and cholesta‐7,24‐dien‐3β‐ol levels increase and the cholesterol level decreases. Cholesta‐7,24‐dien‐3β‐ol appears as a sterol in mature spermatozoa and seems to be a characteristic sterol of hamster cauda epididymal spermatozoa.
Interaction of potentially toxic bile acids with human plasma proteins: Binding of lithocholic (3α‐hydroxy‐5β‐cholan‐24‐oic) acid to lipoproteins and albumin
Authors: Malavolti Mauro , Fromm Hans , Ceryak Susan , Shehan Kathleen L. 
Published: November 2006

AbstractThe binding of lithocholic acid to different plasma fractions was studied. When whole plasma was incubated for 8 hr, approximately 25% of the incubated [14C]lithocholic acid was bound to the lipoprotein and lipoprotein‐free, albumin‐rich fractions. An average of 87.6% of the bound‐lithocholic acid was present in the lipoprotein‐free, albumin‐rich fraction, 7.2% in high density lipoproteins, 2.2% in low density lipoproteins, 1.0% in intermediate density lipoproteins and 2.0% in very low density lipoproteins. Expressed as binding per μg protein, considerably less [14C]lithocholic acid was bound to the lipoprotein‐free, albumin‐rich fraction, than to the lipoproteins. The binding of [14C]lithocholic acid after the incubation of the isolated plasma fractions was similar to that found after the incubation of whole plasma. The highest transfer of [14C]lithocholic acid occurred from the lipoprotein‐free, albumin‐rich fraction to the lipoprotein fractions. The studies indicate, that, although the largest amount of lithocholic acid is bound to the lipoprotein‐free, albumin‐rich fraction, per μg protein, the binding of lithocholic acid to lipoporteins is more pronounced and stable than that bound to the lipoprotein‐free, albumin‐rich fraction. Since lipoproteins, in contrast to albumin, are internalized by most tissues, they may be important carriers into cells of lithocholic acid and other potentially toxic or tumorigenic bile acids.