bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐pressure liquid chromatography of autoxidized lipids: I. Methyl oleate and linoleate
Authors: Neff W. E. , Frankel E. N. , Scholfield C. R. , Weisleder D. 
Published: November 2006

AbstractAutoxidized methyl oleate and linoleate were reduced with NaBH4 and fractionated with a preparative high‐pressure liquid chromatography (HPLC) reverse phase column. Products characterized from reduced‐oxidized oleate included monohydroxy‐ and dihydroxyotadecenoates, dihydroxy‐ and epoxyoctadecanoates. Products characterized from reduced‐oxidized linoleate included hydroxy‐cis,trans‐ andtrans,trans‐octadecadienoates, monohydroxy‐, dihydroxy‐, trihydroxy‐, epoxyhydroxy‐, and epoxyoctadecenoates. Quantitation of oxidation products by HPLC was in agreement with gas chromatography of trimethylsilyl ether derivative. Epoxyoctadecanoate in oleate and epoxy‐ and epoxyhydroxyoctadecenoates in linoleate were the most abundant secondary oxidation products. Some mechanisms are discussed to explain formation of these secondary products.
Effects of ethanol intake on lipoprotein lipase activity in adipose tissue of fasting subjects
Authors: Nilsson‐Ehle Peter , Carlstrom Sven , Belfrage Per 
Published: November 2006

AbstractEthanol (ca. 1 g/kg body weight) was given alone or together with glucose or lipid (mixed triglycerides) perorally to young, fasting subjects. The changes with time (0–6 hr) of lipoprotein lipase activity (LLA) in adipose tissue, plasma glycerol, triglyceride, insulin, blood glucose, and alcohol concentrations were followed. A maximal mean blood alcohol concentration of 0.09% (w/v) was obtained 1 hr after ingestion with no apparent intoxicating effects. Ethanol intake prevented the previously observed [Nilsson‐Ehle, P., S. Carlström and P. Belfrage,Scand. J. Clin. Lab. Invest.35∶373 (1975)] glucose‐induced rapid elevation of adipose tissue LLA but had small effects on this enzymatic activity when given alone or together with lipid. Confirming results by others, ethanol intake decreased plasma glycerol concentration and increased plasma triglycerides, especially after intake of lipid. It is suggested that ethanol intake interferes with the normal carbohydrate‐induced elevation of adipose tissue LLA after a mixed meal, thereby decreasing the removal capacity for circulating dietary lipid and causing enhanced and prolonged alimentary hyperlipemia.
The effect of dietary erucic acid on cardiac triglycerides and free fatty acid levels in rats
Authors: Kramer John K. G. , Hulan Howard W. 
Published: November 2006

AbstractMale Sprague‐Dawley rats, 3 weeks of age, were fed semisynthetic diets containing test oils at 20% by weight for 3 days, 1 week, and 16 weeks. The test oils contained up to 22.3% erucic acid. Growth retardation was evident in rats fed rapeseed oil high in erucic acid, and soybean oil and Tower rapeseed oil diets containing about 5% erucic acid. Cardiac triglyceride accumulation was found in rats fed diets containing about 5% erucic acid but not in rats fed Tower rapeseed oil which contains 0.2% of this acid. The cardiac free fatty acid levels were low, 50–100 μg/g of wet heart tissue, and were not affected by feeding diets containing about 5% erucic acid. Feeding a diet containing a high erucic acid rapeseed oil did result in higher free fatty acid levels but only at 3 days and 1 week; the level at 16 weeks was similar to the other oils. The fatty acid analysis of cardiac triglycerides and free fatty acids showed high percentages of erucic acid at 3 days and 1 week; at 16 weeks these levels had declined significantly. The results indicate that the accumulated erucic and eicosenoic acids, at 3 days and 1 week, accounted for the increase in cardiac free fatty acids when rats were fed the high erucic acid rapeseed oil. There appears to be no evidence that the early cardiac triglyceride or free fatty acid accumulation is related to the formation of the long term myocardial lesions.
The role of dietary protein in hypercholesterolemia and atherosclerosis
Authors: Carroll K. K. 
Published: November 2006

AbstractRabbits become hypercholesterolemic and develop atherosclerotic lesions when fed a cholesterol‐free, semipurified diet. This provides a useful experimental model in which a moderate hypercholesterolemia can be maintained for long periods of time. The elevation of plasma cholesterol and development of atherosclerosis are dependent on the kind of protein in the diet and can be prevented by replacing casein with isolated soy protein. Feeding trials with enzymatic digests or mixtures of amino acids indicate that this difference is at least partly due to the differing amino acid composition of the two proteins. Rabbits on the soy protein diet showed higher rates of oxidation and turnover of cholesterol than those on the casein diet. Dietary protein has generally been considered to be of little significance in the etiology of atherosclerosis in humans, but evidence is accumulating which indicates that it can have a significant influence on human plasma cholesterol levels.
Effect of phthalate esters on serum cholesterol and lipid biosynthesis in liver, testes, and epididymal fat in the rat and rabbit
Authors: Bell Frank P. , Patt Carol S. , Gillies Peter J. 
Published: November 2006

AbstractLipid biosynthesis was studied in vitro in liver, testes, and epididymal fat obtained from rats and rabbits fed di‐(2‐ethylhexyl)phthalate for 4 weeks at levels of 0.5% and 1.0%, respectively. Several differences in response of the two species to DEHP feeding were observed. In rats, but not in rabbits, DEHP feeding significantly reduced the incorporation of labeled mevalonic acid into total sterols (p <0.02), digitonin‐precipitable sterols (p<0.01), and squalene (p<0.05). Inhibition of hepatic sterologenesis previously observed with DEHP feeding in the rat was also observed in the rabbit. In liver minces from the DEHP‐fed rabbits, incorporation of3H‐mevalonic acid into C27 sterols (cholesterol) and C30 sterols (lanosterol) was significantly reduced by about 40% (p<0.05 and p<0.01, respectively), whereas the incorporation of14C‐glycerol 3‐phosphate into phospholipids, and the combined fraction of monoglyceride + diglyceride, was significantly increased (p<0.001 and p<0.01, respectively). In studies with epididymal fat, DEHP feeding did not affect the total incorporation of14C‐acetate or3H‐mevalonate into total saponifiable and nonsaponifiable lipids of either the rat or rabbit. However, in the rat, significantly less of the14C‐acetate (p<0.02) and3H‐mevalonate (p<0.01) that was incorporated appeared in the combined fraction of cholesteryl ester + squalene. In addition, DEHP feeding significantly reduced serum cholesterol (p<0.01) in the rat but not in the rabbit. The results of this study indicate that DEHP feeding is associated with alterations in tissue lipid metabolism and that there are species differences in the response of tissues to DEHP.
Steryl glycoside biosynthesis
Authors: Grunwald Claus 
Published: November 2006

AbstractThe existence of steroid glycosides has been known for many years and, more recently, their derivatives have been described. Steroid glycosides have been isolated from a number of organisms, however, the largest number of these compounds are found in plants. As to glycoside biosynthesis, the sterols are the most extensively studied steroid group. Of the sterols, only the 4‐demethyl sterols have been isolated as glycosides. The glycosidic bond formation is mediated through nucleotide sugars, and UDP‐glucose appears to be the most active glycosyl donor. In cell‐free studies, the pH of the incubation medium is quite critical and depends on the tissue under investigation, but generally the optimum is near pH 7.0. Formation of steryl glycosides is particulate in nature and is stimulated by ATP, Ca2+, and Mg2+. Similar results are obtained, regardless whether the sterol or the sugar moiety is labeled. Formation of acylsteryl glycosides could occur via two pathways: through the acylation of steryl glycosides or through the transfer of an acylglycosyl unit to a sterol moiety. Results from in vitro experiments suggest that acylsteryl glycoside formation occurs via steryl glycosides. Two acyl transfer reactions have been demonstrated; one is microsomal in nature and involves phosphatidylethanolamine, while the other reaction involves a soluble enzyme and requires galactolipids. In vivo experiments, however, indicate that a second pathway may also exist. If cholesterol‐4‐14C is used as substrate, a highly radioactive component can be isolated which is readily converted to acylsteryl glycoside, but not to free sterol or steryl glycoside. It is suggested that this component is an intermediate in acylsteryl glycoside biocynthesis. At present, the nature of the component is unknown. It is quite stable, and acid hydrolysis produces free sterol. Saponification produces two products which in thin layer chromatograms closely resemble acylsteryl glycoside.
Incidence and severity of experimental allergic encephalomyelitis and cerebral prostaglandin synthesis in essential fatty acid deficient and aspirin‐treated rats
Authors: Weston Patricia G. , Johnston Patricia V. 
Published: November 2006

AbstractExperimental allergic encephalomyelitis (EAE) was induced in rats of the Lewis strain fed diets adequate or deficient in essential fatty acids (EFA). After induction of the disease, the diets were supplemented with aspirin (3.75 g/kg diet), and the effects of the drug on the course of EAE and on the synthesis of prostaglandin F (PGF) by brain slices from diseased animals and their Freund controls were examined. Aspirin supplementation delayed the onset of EAE in both dietary groups. EFA‐deficient rats experienced an incidence and severity of the disease similar to that of aspirin‐free, EFA‐deficient rats, while the EFA‐adequate group showed a greater severity but not an increased incidence, compared to aspirin‐free controls. Aspirin treatment led to an increased PGF production by brain slices from rats on either diet and not subjected to an immunochallenge. When the diet was deficient in EFA, challenge with antigen plus adjuvant or adjuvant alone tended to decrease PGF synthesis by brain slices, and when the diet was adequate in EFA, immunochallenge caused a marked depression on PGF synthesis. It was concluded that the PG synthetase inhibitor aspirin can alter the course of EAE in the rat, providing further evidence that PGs or related metabolites may be involved in the immune response in this disease.
The role of dietary fat and hepatic triglyceride secretion in cancer‐induced hypertriglyceridemia
Authors: Kannan Ramaswamy , Wilson Leon , Baker Nome 
Published: November 2006

AbstractGrowth of Ehrlich ascites carcinoma induces hyperlipemia in mice. In the present study using male Swiss‐Webster mice, we examined whether the usual elevations of plasma triglyceride levels in cancerous mice would occur in the absence of dietary fat. Hypertriglyceridemia developed at a similar rate and to a comparable degree in tumorous mice eating a fat‐free (58% glucose) diet and in those fed Purina chow. Maximal hyperlipidemia was observed on day 6 or day 8 in tumorous mice fed either diet. To determine whether the endogenous cancer‐induced hyperlipidemia was due to hypersecretion of triglycerides by the liver, triglyceride secretion rates were studied 0, 2, 4, 6, 8, 10, and 12 days after tumor inoculation using Trition WR‐1339. The secretory rates did not increase prior to or during the development of hypertriglyceridemia in tumorous mice and were not significantly different from those of control mice. On days 10 and 12, triglyceride secretion actually decreased in tumorous mice. Other possible causes for hypertriglyceridemia are discussed in light of the present findings of undetectable differences in triglyceride secretion rates accompanying growth of Ehrlich ascites carcinoma in mice.
Separation of oxidized and unoxidized molecular species of phosphatidylcholine by high pressure liquid chromatography
Authors: Crawford C. G. , Plattner R. D. , Sessa D. J. , Rackis J. J. 
Published: November 2006

AbstractSoy phosphatidylcholine (PC) has been separated into its major molecular species by reversephase high pressure liquid chromatography (HPLC). An aqueous methanol gradient was used that allowed detection of the various species by their absorbance at 206 nm. Oxidized species were detected by their absorbance at 234 nm and were resolved from the unoxidized species. This technique has been used to separate and purify unoxidized dilinoleyl phosphatidylcholine (di 18∶2 PC) from other species of soy PC and to monitor the autoxidation of an aqueous suspension of the purified di 18∶2 PC. Two oxidized products were formed from di 18∶2 PC. Further analysis showed that they were PC, but one of the products contained an oxidized and an unoxidized fatty acid; in the other product, both fatty acids were oxidized.
10α‐Cucurbita‐5,24‐dien‐3β‐ol from gourd seed oil
Authors: Itoh Toshihiro , Tamura Tsutomu , Jeong Tae Myoung , Tamura Toshitake , Matsumoto Taro 
Published: November 2006

Abstract10α‐Cucurbita‐5,24‐dien‐3β‐ol was isolated from the unsaponifiable matter of the seed oil of gourd (Lagenaria leucantha var.Gourda; Cucurbitaceae); it has been previously synthesized, but never found in the plant kingdom. The triterpene alcohol represents the parent compound of a number of cucurbitacins, highly oxygenated tetracyclic triterpenes found in Cucurbitaceae and some other flowering plants.
Distribution of neutral lipids in the tissues of the oysterCrassostrea virginica
Authors: Swift Mary L. , White Debra , Ghassemieh Mohammad B. 
Published: November 2006

AbstractThe content of neutral lipids was determined in the tissues of oysters (Crassostrea virginica Gmelin) collected in June, July and March. The lipid content of starved March oysters was also determined. Oyster tissue from the June harvest contained the highest quantities of triglyceride; starved and July (late spawning) oysters had decreased levels of triglycerides in all tissues except the digestive diverticula/gonad. Free sterol content of all the tissues averaged 1.21 mg equivalent cholesterol/g wet weight tissue, and the steryl ester concentration averaged about 10% of this value. Findings of this investigation indicate that the triglyceride content of oyster tissue fluctuates seasonally and is there‐fore keyed to the physiological state of the animal. Furthermore, triglycerides may be an important energy reserve for reproductive tissue.
Stereospecific analysis of glycerolipids of egg yolk of Japanese quail (Coturnix coturnix japonica)
Authors: Suyama Kyozo , Adachi Susumu , Sugawara Hiroshi , Honjoh Hidemi 
Published: November 2006

AbstractPhosphatidylcholine, phosphatidylethanolamine and triacylglycerol were isolated from egg yolk of the Japanese quail. Fatty acid compositions at the two and three positions of glycerol in the glycerolipids were determined by stereospecific analysis employing phospholipase A2. The distribution of the total number of carbon atoms in the fatty acid moieties of triacylglycerol was also quantitated by high temperature gas liquid chromatography. The distribution of acyl groups in each of the positions of the phosphatidylcholine, phosphatidylethanolamine and triacylglycerol was not random, and each position has a characteristic composition. The phosphatidylcholine and phosphatidylethanolamine had distinctive fatty acid distributions for positionsn‐2 of the triacylglycerol had a predominance of unsaturated fatty acids of which 18∶1 (69.9%) was the major component. Positionsn‐3 contained 49.3% saturated fatty acids and was more saturated than positionsn‐1 by 8.1%. The experimentally determined distribution of the carbon numbers in triacyl glycerol deviated significantly from the distribution predicted by 1‐random‐2‐random‐3‐random association of the fatty acids. The data suggest that in Japanese quail there is marked preferencial synthesis of some triacylglycerols.
Oxidation and isomerization of retinoic acid by iodine and light: A novel preparation of all‐trans‐ and 13‐cis‐4‐oxoretinoic acid
Authors: McKenzie R. M. , Hellwege D. M. , McGregor M. L. , Nelson E. C. 
Published: November 2006

AbstractA mixture of all‐trans‐retinoic acid and iodine in heptane was irradiated. Two oxidation products were isolated by high performance liquid chromatography and identified as all‐trans‐ and 13‐cis‐4‐oxoretinoic acid by nuclear magnetic reasonance, ultra violet, Infrared spectroscopy, and mass spectral analysis. Under the same conditions, but without light, a mixture of all‐trans‐ and 13‐cis‐retinoic acid resulted. The corresponding methyl esters were obtained when methyl all‐trans‐retinoate was used in place of all‐trans‐retinoic acid.
Effect of low levels of dietary fish oil on fatty acid desaturation and tissue fatty acids in obese and lean rats
Authors: Cao Jun‐Ming , Blond Jean Paul , Juaneda Pierre , Durand Georges , Bézard Jean 
Published: November 2006

AbstractThe effect of very low levels of dietary long‐chain n−3 fatty acids on Δ6 desaturation of linoleic acid (18∶2n−6) and α‐linolenic acid (18∶3n−3), and on Δ5 desaturation of dihomo‐γ‐linolenic acid (20∶3n−6), in liver microsomes and its influence on tissue fatty acids were examined in obese and lean Zucker rats and in Wistar rats. Animals fed for 12 wk a balanced diet containing ca. 200 mg of long‐chain polyunsaturated n−3 fatty acids per 100 g of diet were compared to those fed the same amount of α‐linoleic acid. Low amounts of long‐chain n−3 fatty acids greatly inhibited Δ6 desaturation of 18∶2n−6 and Δ5 desaturation of 20∶3n−6, while Δ6 desaturation of 18∶3n−3 was not inhibited in Zucker rats and was even stimulated in Wistar rats. Inhibition of the biosynthesis of long‐chain n−6 fatty acids was reflected in a decrease in arachidonic acid (20∶4n−6) content of serum lipids when fasting, and also in the phospholipid fatty acids of liver microsomes. On the contrary, heart and kidney phospholipids did not develop any decrease in 20∶4n−6 during fish oil ingestion. Docosahexaenoic acid (22∶6n−3), present in the dietary fish oil, was increased in serum lipids and in liver microsome, heart, and kidney phospholipids.
Hepatic lipid abnormalities in a chemical/viral mouse model for Reye's Syndrome
Authors: Murphy M. G. , Archambault‐Schertzer L. , VanKessel J. , Digout S. C. , Malatjalian D. A. , Crocker J. F. S. 
Published: November 2006

AbstractWe have examined hepatic lipid profiles in a mouse model for Reye's Syndrome (RS) in which young animals are exposed to nontoxic doses of an industrial pesticide emulsifier and subsequently are infected with sublethal doses of mouse‐adapted human Influenza B (Lee) virus (FluB). The purpose of this study was to determine whether liver lipid content was altered in the mice, the time course of any changes, and whether lipid changes were consistent with liver pathology. Neonatal mice exposed dermally to the emulsifier, Toximul MP8 (Tox), had significantly elevated levels of hepatic cholesterol, with otherwise normal lipid composition. Subsequent inoculation of the mice with FluB significantly increased mortality rate. The combined Tox+FluB treatment had several significant effects on liver lipids, including a transient increase in phospholipid (PL) content, a reduction in neutral glycerides and persistently high cholesterol levels. Abnormalities in fatty acid profiles included an apparent elevation in medium chain fatty acids and increased ratios of PL arachidonic to docosahexaenoic acids. Histologically, there was no evidence of fat accumulation in the liver; however, hepatic mitochondria had severe structural abnormalities characteristic of RS. These studies demonstrate that chemical‐dependent enhancement of viral virulence is associated with significant alterations of hepatic lipids. We believe that these abnormalities are related to mitochondrial structural damage in RS despite the absence of hepatic steatosis.
Effects of aging on the composition and metabolism of docosahexaenoate‐containing lipids of retina
Authors: Rotstein N. P. , Ilincheta de Boschero M. G. , Giusto N. M. , Aveldaño M. I. 
Published: November 2006

AbstractThe amount of docosahexaenoate (22∶6n−3)‐containing phospholipid species decreases with aging in the rat retina. Most lipids, but especially choline and serine glycerophospholipids, show a significant fall in 22∶6n−3, which is not compensated by increases in other polyenoic fatty acids. The decrease not only affects 22∶6 but also various very long chain n−3 hexaenoic fatty acids which, in phosphatidylcholine, have up to 36 carbon atoms, and which are probably synthesized by successive elongations of 22∶6n−3. The in vitro incorporation of [2‐3H] glycerol into retinal lipids indicates that the de novo biosynthetic pathways are not impaired by aging. The incorporation of [1‐14C]docosahexaenoate is significantly stimulated into all lipids of aged retinas, but to the largest extent in those showing the largest decreases in 22∶6, especially in choline glycerophospholipids. The results indicate that the decreased levels of 22∶6 with aging are due not to an impaired activity of the enzymes involved in the synthesis and turnover of phospholipids but to a decreased availability of this polyene in the retina. It is suggested that this may stem from a defect in some of the enzymatic steps that lead to the synthesis of 22∶6n−3, probably that catalyzed by Δ4 desaturase, the effect on longer hexaenes being secondary to the decreased synthesis of 22∶6.
Two procedures to remove polar contaminants from a crude brain lipid extract by using prepacked reversed‐phase columns
Authors: Kyrklund Titus 
Published: November 2006

AbstractTwo procedures were developed using prepacked, reversed‐phase columns (Bond Elut) for the separation of lipids from water‐soluble contaminants. A crude lipid extract from brain tissue, was diluted stepwise with a methanol/water (method 1) or a methanol/saline (method 2) mixture and, with each step, was passed through the column. As the polarity of the solvent was increased, all lipids became bound to the column, while the water‐soluble compounds remained in the eluate. After three subsequent dilutions and column elutions, the eluate containing the more polar contaminants was discarded. The bound lipids were then eluted with a small volume of chloroform/methanol (1∶2, v/v). Alternatively two fractions were eluted, the first fraction eluted with methanol/water (12∶1, v/v), contained gangliosides, phosphatidyl‐serine, phosphatidylinositol, phosphatidic acid and sulfatides. The second fraction, eluted with chloroform/methanol (1∶2, v/v), contained all remaining phospholipids, cerebrosides and cholesterol. For both methods a quantitative recovery of cholesterol and phospholipids was obtained. In method 2, when water was replaced by saline in the dilution solvent mixture, gangliosides were also bound and quantitatively recovered.