bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of dietary vitamin E, selenium, and polyunsaturated fats on in vivo lipid peroxidation in the rat as measured by pentane production
Authors: Dillard Cora J. , Litov Richard E. , Tappel Al L. 
Published: November 2006

AbstractStarting at 21 days of age, groups of six rats each were fed a basal Torula yeast diet supplemented with 0,4% L‐methionine and varying amounts of vitamin E as dl‐alpha tocopherol acetate, selenium as sodium selenite, and with either 10% stripped corn oil, stripped lard, or coconut oil. By 7 wk, pentane production by rats fed a corn oil diet deficient in both vitamin E and selenium was twice that by rats fed 0.1 or 1 mg of selenium per kg of the same basal diet. Blood glutathione peroxidase activity after 7 wk was proportional to the logarithm of dietary selenium. Groups of rats fed the vitamin E‐ and selenium‐deficient diets with lard or coconut oil had one‐half the pentane production of rats fed the vitamin E‐ and selenium‐deficient corn oil diets. The plasma level of linoleic plus arachidonic acid was 1.8 times greater on a wt % basis in rats fed corn oil than in rats fed lard or coconut oil as the fat source. Pentane production by rats fed 40 i.u. dl‐alpha tocopherol acetate per kg of the selenium‐deficient corn oil diet was one‐sixth of that by rats fed the same diet without vitamin E; the plasma of the rats fed the vitamin E‐supplemented corn oil diet had a level of vitamin E that was about six times greater than that of the rats fed the vitamin E‐deficient corn oil diet.
Neural factors in experimental degenerative arteriopathy
Authors: Gutstein William H. , Parl Fritz 
Published: November 2006

AbstractIntermittent electrical stimulation of the lateral hypothalamus of rats performed for 30 min to 6 hr, results in hyperlipidemia and endothelial cell damage of the aorta and coronary arteries. Hyperlipidemia is related to transient biliary obstruction elicited by hypothalamic stimulation and is characterized by elevation of the cholesterol, phospholipid, and triglyceride fractions. Endothelial cell damage is observed ultrastructurally as plasma membrane degeneration with detachment and the formation of large spaces (“vacuoles”). Thus, neural factors may be implicated in inducing conditions associated with early atherogenesis. Stimulation carried out for longer time intervals would be expected to produce more advanced lesions. However, the role of neural transmission per se (i.e., without hyperlipidemia) in producing arteriopathy is not clearly defined from these experiments. In rats, the lesser splanchnic nerve forms the major innervation of the abdominal aorta. In animals fed normal diets, chronic intermittent stimulation of this nerve (up to 3 weeks) resulted in advanced arteriosclerotic changes with intimal fibrosis and calcification. On histologic examination, lipid deposits appeared to be absent from these lesions. Animals stimulated for shorter periods of time exhibited earlier changes associated with atherogenesis, such as endothelial damage, elastic reduplication, and adherent microthrombi. Thus, direct neural transmission, especially if excessive, plays a role in producing arteriopathy. Hyperlipidemia, if persistent, could modify these lesions so that they would accumulate plasma lipids. Experiments to test this hypothesis are currently in progress.
Ecdysone metabolism: Ecdysone dehydrogenase‐isomerase
Authors: Nigg H. N. , Svoboda J. A. , Thompson M. J. , Kaplanis J. N. , Dutky S. R. , Robbins W. E. 
Published: November 2006

AbstractAn enzyme system that converts α‐ecdysone to its hormonally less active 3α‐epimer was detected only in the midgut of the tobacco hornworm,Manduca sexta (L.). This system appears to be specific for the ecdysones and may represent a metabolic control point for regulating molting hormone activity.
Effect of dietary bile acids, cholesterol, and β‐sitosterol upon formation of coprostanol and 7‐dehydroxylation of bile acids by rat
Authors: Cohen B. I. , Raicht R. F. , Mosbach E. H. 
Published: November 2006

AbstractDuring studies of sterol metabolism in the rat, the fecal neutral sterol fraction was analyzed by a combination of thin layer chromatography and gas liquid chromatography. On a stock diet of rat chow supplemented with 5% corn oil, the rats excreted 14.5 mg/day of total neutral sterols. Coprostanol comprised 35% (5 mg/day) of this fraction. When the diet was supplemented with 0.5% sodium taurochenodeoxycholate, the amount of coprostanol in the feces remained the same as in the controls (3.2 mg/day, 32%). The addition of 0.5% sodium taurocholate to the diet resulted in a fivefold reduction of coprostanol formation (0.6 mg/day, 8%). When 1.2% cholesterol was added to the stock diet, the amount of coprostanol present in the feces decreased to an average of 11% compared to controls, but the absolute amount formed was greater (35 mg/day). On a diet enriched with 0.8% β‐sitosterol, the rats, on the average, converted 23% of the cholesterol to coprostanol. Feeding diets enriched with sodium taurochenodeoxycholate and sodium taurocholate reduced the 7‐dehydroxylation of primary bile acids in the feces by 28% and 42%, respectively. The conversion of primary bile acids to secondary bile acids in the feces of control, cholesterol, and β‐sitosterol fed rats was the same (64%).
Rapid transmethylation of microgram amounts of phosphatidylcholine on potassium methoxide/celite columns
Authors: Marmer William N. 
Published: November 2006

AbstractA rapid and convenient method for the determination of acyl groups in phosphatidylcholine (PC) has been developed. Transmethylation reactions were carried out on potassium methoxideimpregnated Celite microcolumns that were readily prepared from Pasteur pipettes. The methods were tested on microgram amounts of synthetic L‐α‐phosphatidylcholines (di‐14∶0; di‐18∶2; α‐16∶0‐β‐14∶0) and on egg yolk lecithin, in methylene chloride or hexane solution. Transmethylation of these lipids occurred rapidly at room temperature. Gas liquid chromatographic (GLC) analysis of the product methyl esters demonstrated that the reaction was neither selective for one acyl position of PC over the other, nor sensitive to the amount of unsaturation within the acyl group. The results of the acyl group analysis of natural egg yolk lecithin compared favorably with the results from an established procedure.
Bile acids LVII. Bile acids and colorectal cancer
Authors: Davis J. Wendell , Elliott William H. 
Published: November 2006

AbstractSignificant correlations have been reported by epidemiologists between the mortality from colorectal cancer in various populations and the consumption of meat or lipids by these populations. These have directed considerable attention to possible relationships between diet and the occurrence of this neoplasm. We have carried out studies of the composition of bile from rats as influenced by diets of varying lipid content. Two cannulas were surgically implanted to form an externalized bile duct through which bile was drained from the common duct and returned to the duodenum. Small aliquots were analyzed for total bile acids by enzymatic assay and for individual bile acids by high‐pressure liquid chromatography, gas chromatography and gas chromatography‐mass spectrometry. Animals consuming diets highest in lipid content provided bile with the greatest amounts of bile acids. The primary bile acids, taurocholic, taurochenodeoxycholic, and tauro α‐ and β‐muricholic acids made up more than 99% of the 3α‐hydroxy bile acids and were found in approximate molar ratio of 2∶1∶1. Either complete drainage of bile without return to the duodenum, or biliary tract obstruction had pronounced influence on the rate of secretion of bile and its composition.
Leucine as an in vitro precursor to lipids in rat sciatic nerve
Authors: Stillway Lewis W. , Weigand Dorothy A. , Buse Maria G. 
Published: November 2006

AbstractThe in vitro incorporation of leucine, isoleucine and pyruvate into lipids was compared and the possibility that leucine might serve as anin situ precursor to the correspondingiso fatty acids in the rat sciatic nerve was studied. The relative incorporation of14C from leucine into lipids vs. nonlipids was 20%, and the incorporation of label into total lipids from leucine was one‐half that from pyruvate. The incorporation of label from leucine and pyruvate into sterols was nearly equivalent, but the incorporation of label into all other lipid classes from leucine was less than that from pyruvate, and the incorporation of label from isoleucine into lipids was much less in all cases. No detectable label from leucine was incorporated into brached chain fatty acids. It is concluded that leucine may be a substantial in vitro precursor to all major lipids in peripheral nerve, especially sterols. The possibility and significance of a leucine catabolic pathway in the cytosol in relation to availability of 3‐hydroxy‐3‐methylglutaryl CoA for sterol biosynthesis is discussed.
Interaction of human plasma high density lipoprotein HDL2 with synthetic saturated phosphatidylcholines
Authors: Gong Elaine L. , Nichols Alex V. 
Published: November 2006

AbstractThe interaction of human plasma high density lipoprotein HDL2 (d 1.063–1.125 g/ml) with sonicated dispersions of synthetic saturated phosphatidylcholines, dipalmitoyl‐ (diC16PC), dimyristoyl‐ (diC14PC), didodecanoyl‐ (diC12PC), didecanoyl‐ (diC10PC), and dioctanoyl‐ (diC8PC) L‐alpha phosphatidylcholine, was investigated. Incubation (4.5 hr, 37 C) of HDL2 with diC14PC, diC12PC, diC10PC and diC8PC followed by gradient gel electrophoresis or preparative ultracentrifugation resulted in a redistribution of apolipoprotein A‐I (apoA‐I). The extent of redistribution depended on the molar ratio of the phospholipid to HDL2 in the incubation mixture. Redistributed apoA‐I occurred as lipid‐free apoA‐I and/or as complexes of apoA‐I with phosphatidylcholine. Increasing the length of time of ultracentrifugation of the interaction mixtures did not increase the extent of redistribution. No redistribution of apoA‐I was detected following incubation and gradient gel electrophoresis or preparative ultracentrifugation of mixtures of HDL2 with dispersions of diC16PC.
Incorporation ofcis‐ andtrans‐octadecenoic acids into the membranes of rat liver mitochondria
Authors: Høy C. ‐E. , Hølmer G. 
Published: November 2006

AbstractThe incorporation of dietary isomeric fatty acids into the membranes of liver mitochondria was investigated. Three groups of rats were fed diets containing 3% sunflower seed oil plus 15%, 20%, or 25% partially hydrogenated arachis oil. A fourth group was fed 25% partially hydrogenated arachis oil, but no sunflower seed oil. All diets were given for 3, 6, or 10 weeks. After 10 weeks, the content oftrans fatty acids in the lipids of the mitochondrial membranes was 15–19% of the total fatty acids. The composition of thetrans‐ and thecis‐octadecenoic acids in the lipids of the mitochondrial membranes was similar for all groups supplemented with sunflower seed oil (SO), irrespective of time and dietary level of partially hydrogenated arachis oil (HAO). Thecis 18∶1 (n−8), which was a major isomer of the partially hydrogenated arachis oil, was almost excluded from the mitochondrial fatty acids. Likewise, the content oftrans 18∶1 (n−8) was considerably lower in the mitochondrial lipids than in the diet. On the contrary, the content oftrans 18∶1 (n−6) was higher in the mitochondrial lipids than in the diet. In the group fed without sunflower seed oil, isomers of linoleic acid and arachidonic acid were observed in the lipids of mitochondrial membranes.
Hydrophilic bile acids: Prevention and dissolution experiments in two animal models of cholesterol cholelithiasis
Authors: Cohen Bertram I. , Mikami Takahiro , Ayyad Nariman , Ohshima Akira , Infante R. , Mosbach Erwin H. 
Published: November 2006

AbstractThe effects of β‐muricholic acid and hyocholic acid on cholesterol cholelithiasis were examined in two animal models. The following experiments were carried out: A) In a gallstone prevention study, prairie dogs were fed the lithogenic diet with or without 0.1% β‐muricholic or 0.1% hyocholic acid for eight weeks. B) In a second prevention study, hamsters were fed the lithogenic diet with or without 0.1% β‐muricholic acid or 0.1% hyocholic acid for six weeks. C) In a gallstone dissolution study, hamsters were fed the lithogenic diet for six weeks to induce stones; stone dissolution was examined during administration of a cholesterol‐free purified diet with or without 0.1% β‐muricholic acid or 0.1% hyocholic acid. In the prevention study in prairie dogs (A), both bile acids failed to prevent stone formation, the cholesterol saturation index of bile was 0.89 in the lithogenic controls, remained unchanged with hyocholic acid and increased to 1.52 in the β‐muricholic acid group. In the prevention study in hamsters (B), β‐muricholic acid completely inhibited the cholesterol cholelithiasis (0% stone incidence); the cholesterol saturation index of bile was 1.78 (compared to lithogenic controls, 1.37). Hyocholic acid reduced stone incidence to 16% with a cholesterol saturation index of 0.98. In the dissolution study in hamsters (C), preexisting cholesterol gallstones were not dissolved by either hydrophilic bile acid after feeding these bile acids for an additional six weeks; at the end of the experiment, the cholesterol saturation indices were below unity. These studies suggest that, in the hamster animal model, hydrophilic bile acids may be useful for the prevention of gallstones but not dissolution of preestablished cholesterol gallstones.
Cyclic fatty esters: Hydroperoxides from autoxidation of methyl 9‐(6‐propyl‐3‐cyclohexenyl)‐(Z)8‐nonenoate
Authors: Awl Richard A. , Frankel Edwin N. , Weisleder David 
Published: November 2006

AbstractAutoxidation of the cyclic fatty acid ester, methyl 9‐(6‐propyl‐3‐cyclohexenyl)‐(Z)8‐nonenoate (I) was investigated to characterize the hydroperoxide isomers formed and to provide basic information on their chemistry, detection and effect on the quality of polyunsaturated cooking oils. Oxidation at 60 C with 1% hydroperoxide initiator produced a monohydroperoxide fraction containing five positional isomers (7‐, 11‐, 12‐, 13‐ and 14‐OOH), resolved by high performance liquid chromatography, as their allylic hydroxy esters. Their structures were established by1H‐ and13C‐NMR spectroscopy and by capillary gas chromatography‐mass spectrometry (GC‐MS) as trimethylsilyl ether derivatives. Two additional isomers (8‐ and 9‐OOH) were detected by GC‐MS in only trace (<1%) quantities. Capillary GC resolved some geometric and stereoisomers, as well as positional isomers. Compared to photosensitized oxidation, two additional positional isomers (11‐ and 14‐OOH) were produced by autoxidation. More stereoisomers were formed, and oxidation of the ring double bond was favored 8∶1 over that of the side chain. This selectivity may be attributed to greater steric hindrance for oxygen attack at the side‐chain double bond. A free radical mechanism is proposed to explain the greater isomeric complexity of the hydroperoxide products compared to photosensitized oxidation.
Interferon α/β induces changes in the metabolism of polyenoic phospholipids and diacylglycerols in the livers of suckling mice
Authors: Zwingelstein Georges , Brichon Gerard , Meister Roger , Maury Chantal , Gresser Ion 
Published: November 2006

AbstractSuckling mice were injected daily from birth for 10 days with potent preparations of mouse interferon α/β. Interferon treatment resulted in a markedly lower concentration of polyunsaturated fatty acids (20∶4ω6 and 22∶6ω3) in the two principal liver phospholipids, phosphatidylcholine and phosphatidylethanolamine, than in livers of control‐treated mice. This effect appeared to correlate with a low level of synthesis of polyunsaturated phospholipids in the livers of interferon‐treated mice. Thus, in control mice, synthesis of species of polyunsaturated phospholipids increased markedly in the first 10 days of life, whereas in 10‐day‐old interferontreated mice, the level of synthesis of species of polyunsaturated phospholipids was comparable to that in newborn mice. In parallel, a marked increase in the diacylglycerol content without change of its renewal was observed in the livers of interferon‐treated mice. We suggest that interferon treatment results in an inhibition of one of the processes that leads to activation of the enzymatic systems responsible for the synthesis of species of polyunsaturated phosphatidylcholine and phosphatidylethanolamine in the liver of suckling mice. It seems likely that these results are related to the inhibition of liver cell maturation and the marked cell necrosis that are observed in interferon‐treated suckling mice.
Rapid isolation of microsomes for studies of lipid peroxidation
Authors: Albro Phillip W. , Corbett Jean T. , Schroeder Joanna L. 
Published: November 2006

AbstractConventional isolation of microsomes by high‐speed centrifugation from isotonic sucrose requires exposure to air for several hours, leading to the formation of low levels of lipid peroxidation products. Sucrose interferes in protein and malondialdehyde assays and provides no protection against lipid peroxidation during workup. A new procedure for the purification of microsomes from rat liver substitutes mannitol (a hydroxyl radical scavenger) for sucrose and takes advantage of the properties of morpholinopropane sulfonic acid (MOPS) buffer and triethylenetetramine to provide protection against lipid peroxidation during the rapid (less than one hour) workup and subsequent low‐temperature storage. The microsomal fractions prepared by the proposed method are free of detectable mitochondrial contamination and at least as pure overall as those prepared by the conventional method, but they have higher glucose‐6‐phosphatase and laurate hydroxylase activities and significantly less malondialdehyde than conventional microsomes at the time isolation is complete. Laurate hydroxylase activity is more stable during frozen storage in mannitol medium. The kinetics of lipid peroxidation in vitro are quite different for microsomes prepared by the two methods.
A facile synthesis and carbon‐13 nuclear magnetic resonance spectral properties of 7‐ketocholesteryl benzoate
Authors: Parish Edward J. , Wei Tsao‐Yi , Livant Peter 
Published: November 2006

AbstractThis paper presents a modified method of the selective allylic oxidation of cholesteryl benzoate. Pyridinium chlorochromate, in refluxing benzene, has been found to be an effective and convenient reagent for the efficient oxidation of cholesteryl benzoate to 7‐ketocholesteryl benzoate in high yield. Also included herein are the carbon‐13 nuclear magnetic resonance spectral properties of 7‐ketocholesteryl benzoate and cholesteryl benzoate.
Fate of 7,12‐dimethylbenz(a)anthracene absorbed from the rat intestine and transported in chylomicrons
Authors: Lindstrom Mats B. , Barrowman James A. , Borgstrom Bengt 
Published: November 2006

AbstractChylomicrons obtained from the thoracic duct of rats fed [3H]7,12‐dimethylbenz(a)anthracene (DMBA), a polycyclic aromatic hydrocarbon, were infused intravenously into rats with bile fistulas. Over 17 hr, 55.9±3.2% (mean ±SEM) of the radioactivity was recovered in bile and 6.7±0.5% in urine. Minor amounts were deposited in liver, kidneys and epididymal fat pads. Injection of DMBA in ethanolic solution gave a similar pattern, while biliary DMBA metabolites resulted in higher recovery in urine and lower recovery in fat. In conclusion, the major part of chylomicron DMBA is rapidly excreted via the biliary route, while a fraction is probably retained in adipose tissue.
Net lipid transfer between lipoproteins in fish‐eye disease plasma supplemented with normal high density lipoproteins
Authors: Holmquist Leif , Carlson Lars A. 
Published: November 2006

AbstractNative fish‐eye disease plasma, which is deficient of both high density lipoproteins (HDL) and lecithin‐cholesterol acyltransferase activity (α‐LCAT), processing the free cholesterol of these lipoproteins, has been supplemented with normal isolated HDL2 or HDL3 and incubated in vitro at 37 C. After incubation for 0,7.5 and 24 hr the very low density (VLDL) and low density (LDL) lipoproteins as well as HDL were isolated, and their contents of triglycerides, phospholipids and free, esterified and total cholesterol were quantified. The resulting net mass transfer of the different lipids revealed a functioning transfer of cholesteryl esters and all other analyzed lipids between the lipoproteins, although no de novo esterification of the HDL cholesterol by LCAT in this plasma occurred. In accordance with previous findings there was a functioning esterification process of the free cholesterol of the combined VLDL and LDL of fish‐eye disease plasma. The present results make it reasonable to conclude that the lack of HDL cholesterol esterification in this disease is not a result of a deficiency of cholesteryl ester transfer or lipid transfer activities.
Efficacy of linoleic acid administered rectally as monoglyceride
Authors: Christophe Armand , Hill Eidon G. , Holman Ralph T. 
Published: November 2006

AbstractThe potential of the rectal route for administration of essential fatty acids (EFA) as monoglyceride (MG) was investigated. EFA‐deficient rats were supplemented with 14 mg linoleic acid/day for 3 days. Supplementation was either by oral administration as corn oil, orally as corn oil‐derived MG or rectally as MG. The patterns of polyunsaturated fatty acids (PUFA) in liver and serum lipids, characteristic of EFA deficiency, were altered in the direction of normalcy in similar magnitude by all modes of supplementation, indicating that the rectal route may be useful for administration of EFA. The amounts of phospholipids (PL) and free fatty acids (FFA) in liver changed by all modes of administration. The magnitude of change of total PL and of FFA in liver depended upon the chemical form in which linoleic acid was administered and the route of administration, indicating that these factors affect lipid metabolism.