bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sitosterol on the rate‐limiting enzymes in cholesterol synthesis and degradation
Authors: Boberg Kirsten Muri , Åkerlund Jan‐Erik , Björkhem Ingemar
Published: November 2006

Attempts were made to develop an animal model for phytosterolemia. Infusion of Intralipid containing 0.2% sitosterol in rats gave circulating levels of sitosterol of about 2.5 mmol/l, which is similar to or higher than those present in patients with untreated phytosterolemia. In addition, the infusions gave serum levels of cholesterol nearly twice those obtained in rats infused with Intralipid alone or Intralipid containing 0.2% cholesterol. The hepatic HMG‐CoA reductase activity was unaffected or slightly increased by the sitosterol infusions (not statistically significant). The cholesterol 7α‐hydroxylase activity was slightly depressed (ca. 30%). In the case of 7α‐hydroxylation of endogenous cholesterol, the depression reached statistical significance (p<0.05). The microsomal content of sitosterol in the sitosterol‐infused rats was about 30% of that of microsomal cholesterol. The effect of sitosterol on 7α‐hydroxylation of cholesterol was investigated by incubations of acetone powder of rat liver microsomes with mixtures of cholesterol and sitosterol. Sitosterol mixed with cholesterol to a composition similar to that found in the above microsomal fraction had a depressing effect on 7α‐hydroxylation of cholesterol. This degree of depression was of the same magnitude as that found in the sitosterol infusion experiments. The possibility is discussed that the hypercholesterolemia obtained in the β‐sitosterol‐infused rats is due to the inhibitory effect of sitosterol on the cholesterol 7α‐hydroxylase.
Phosphatidylinositol 4,5‐bisphosphate phospholipase C activity in particulate preparations from rat brain
Authors: Bergers Mieke , Lendi Sonja , Mier Paul D.
Published: November 2006

We describe the hydrolysis of phosphatidylinositol 4,5‐bisphosphate by a particulate rat brain preparation in the presence of the cationic detergent, cetrimide. The optimum cetrimide concentration was in the range 0.2–0.4 mg/ml; at higher or lower concentrations, the reaction rate diminished abruptly, suggesting that the electrical charge density of the micelle is critical for enzymatic attack. In other respects, such as its partial requirement for Ca++ and its pH optimum of about 7.0, the particulate enzyme seems similar to soluble preparations which have been reported previously. Interestingly, the particulate preparation could be stimulated about fourfold by a soluble brain extract in the presence of 1 mM guanosine triphosphate, confirming that the enzyme is the catalytic subunit in a membrane‐bound signal‐transduction system.
Dietary N−6 and N−3 fatty acids and salt‐induced hypertension in the borderline hypertensive rat
Authors: Mills David E. , Ward Ron P. , Mah Marvin , DeVette Linda
Published: November 2006

This study examined the effects of salt‐loading on blood pressure (BP) development in the borderline hypertensive rat (BHR) and its modification by dietary n−3 and n−6 fatty acids. In experiment 1, 4 groups (n=10/group) of male BHR receiving 1% NaCl as a replacement for tap water were placed on chow enriched with either olive oil (OL), sunflower oil (SUN), evening primrose oil (EPO) or fish oil for 6 weeks. BP, heart rate, body weight, water, Na+ and K+ intake and urinary output were measured weekly. SUN and fish oil reduced the pressor response to salt seen vs the OL group by 50%, and EPO abolished the pressor response, reducing BP below control levels. The BP response was unrelated to either food intake or water and electrolyte intake and excretion. In experiment 2, male BHR received water +/− 18∶3n−6 (0.04 mg/hr in OL via ip pump) or 1% NaCl +/− 18∶3n−6 (n=12/group) for 12 weeks, followed by 2 weeks recovery on tap water. Salt increased BP, and 18∶3n−6 decreased this response, but had no effect on animals receiving tap water. In experiment 3, effects of 3 doses of 18∶3n−6 (0.04, 0.08, and 0.12 mg/hr) on the pressor response to 1% NaCl were examined. All doses reduced the BP response to salt vs controls with no dose‐response. These data suggest that the BHR is genetically salt‐sensitive, and that dietary n−3 and n−6 fatty acids can attenuate the cardiovascular response to salt in this model.
Serum lipoprotein and apoprotein concentrations in 4‐(4‐chlorophenyl)‐2‐hydroxytetronic acid and clofibrate‐treated cholesterol and cholic acid‐fed rats
Authors: Kamanna Vaijinath S. , Newman Howard A. I. , Patel Suman T. , Tehim Ahsok K. , Witiak Donald T. , Feller Dennis R.
Published: November 2006

Influence of clofibrate and an aci‐reductone, 4‐(4‐chlorophenyl)‐2‐hydroxytetronic acid (CHTA) on lipoproteins and apoproteins was studied in cholesterol‐ plus cholic acid‐fed rats. CHTA (0.4 mmol/kg body wt, twice daily) significantly lowered serum total cholesterol and triglyceride concentrations at both 10 and 16 days, whereas clofibrate at the same dose did not alter serum cholesterol levels, but elevated serum triglyceride concentrations at 16 days. The abnormal cholesterol‐rich very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL) and low density lipoproteins (LDL) produced by cholesterol plus cholic acid were significantly reduced in their cholesterol content by treatment with CHTA, a compound having an oxidation reduction potential. Conversely, clofibrate administration increased VLDL‐cholesterol with concomitant decreases in IDL‐ and LDL‐cholesterol concentrations. Administration of CHTA to cholesterol‐ plus cholic acid‐fed rats significantly increased concentrations of VLDL and IDL, but had no effect on HDL protein. Both CHTA and clofibrate administration to cholesterol‐ plus cholic acid‐fed rats significantly lowered IDL protein concentrations.

Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) studies of apoproteins revealed that clofibrate treatment significantly reduced apoC‐III and C‐II in VLDL, C‐II in IDL, and apoA‐IV and A‐I in HDL. Rats treated with CHTA significantly raised apoC‐II and C‐III in HDL.

Isoelectric focusing (IEF) of VLDL apoproteins showed a significant decrease in apoC‐II, C‐III‐0 and apoC‐III‐3 in clofibrate‐treated animals. Thus, the mechanism for antilipidemic action of the oxidation reduction compound, CHTA, which differs markedly from the prototype drug, clofibrate, is independent from major apoprotein modification.
Cardiac membrane vitamin E and malondialdehyde levels in heart muscle of normotensive and spontaneously‐hypertensive rats
Authors: Janero David R. , Burghardt Barbara
Published: November 2006

The vitamin E (α‐tocopherol) and free and bound malondialdehyde (MDA) in ventricular heart muscle and myocardial membrane from Wistar‐Kyoto (W/K) normotensive and spontaneously hypertensive (SH) rats have been measured directly by high performance liquid chromatography (HPLC). Thiobarbituric acid‐reactive substance (TBA‐RS) in the myocardium and heart‐muscle membrane of the two strains was also quantified by a colorimetric TBA test. It was found that SH‐rat myocardium and myocardial membrane contained more than 3‐fold less α‐tocopherol than did heart muscle and cardiac membrane of the normotensive rat. Coincident with this relative vitamin E deficiency were several‐fold greater amounts of MDA and TBA‐RS in SH‐rat myocardium and myocardial membrane. Most (87%) of the MDA in SH‐rat heart muscle, but only 40% in W/K‐rat heart muscle, was free (i.e., unbound). These results offer direct evidence that SH‐rat myocardium is vitamin E‐deficient and highly peroxidative, relative to cardiac muscle of the normotensive W/K parent strain. The lower vitamin E content of SH‐rat myocardium is particularly striking, because SH‐rat myocardial membrane was found to contain ∼35% more phospholipid than myocardial membrane in the W/K rat. Although the amounts of myocardial TBA‐RS are greater in the SH strain, they do not reflect the actual MDA profiles of the heart muscles or the heart membranes and cannot be used as a quantitative index of cardiac oxidative‐injury status due to non‐MDA TBA‐RS in both strains.
Effect of dietarytrans fatty acids on some membrane‐associated enzymes and receptors in rat heart
Authors: Alam Syed Q. , Ren Yun‐Fang , Alam Bassima S.
Published: November 2006

Three groups of male weanling Sprague‐Dawley rats were fed diets containing 20% corn oil, 20% partially hydrogenated soybean oil (PHSBO) or 18% PHSBO +2% corn oil. PHSBO contained about 48% of its total fatty acids astrans‐octadecenoate. Rats were killed after 16–18 weeks of feeding the various diets, hearts were dissected and crude sarcolemma was prepared by differential centrifugation. The activities of ouabain‐sensitive (Na++K+)ATPase were significantly lower in membranes of rats fed 20% PHSBO than the control rats fed 20% corn oil. The feeding of 2% corn oil with 18% PHSBO resulted in partial restoration of the enzyme activity. The maximum number of [3H]ouabain‐binding sites (Bmax) was also lower in cardiac membranes of rats fed 20% PHSBO than those fed 20% corn oil. Similar to (Na++K+)ATPase activity, some restoration of the number of [3H]ouabain‐binding sites was observed when 2% corn oil was fed with 18% PHSBO‐containing diet. There was no difference in the binding affinity of the radioligand for the receptor among the 3 dietary groups. Adenylate cyclase activities (fluoride‐, isoproterenol‐ and forskolinstimulated) were lower in membranes of rats fed 20% PHSBO or 18% PHSBO +2% corn oil than in the control group fed 20% corn oil. Density of the β‐adrenergic receptor was the lowest in cardiac membranes of rats fed 20% PHSBO. The feeding of 2% corn oil with 18% PHSBO resulted in partial restoration of the maximum number of [3H]dihydroalprenolol (DHA)‐binding sites. The affinity of the binding sites was, however, not affected by the type of the dietary fat. The results of this study suggest that dietarytrans fatty acids can affect the activities of (Na++K+)ATPase and adenylate cyclase and the density of digitalis and β‐adrenergic receptors in rat heart.
Mechanisms of linoleic acid uptake by rabbit small intestinal brush border membrane vesicles
Authors: Ling Kit‐Yin , Lee Hsin‐Yi , Hollander Daniel
Published: November 2006

We examined the initial transport of a long‐chain unsaturated fatty acid, linoleic acid, by brush border membrane vesicles isolated from rabbit small intestine. This preparation allowed us to examine the transport of linoleic acid across the brush border membrane without the effect of the unstirred water layer or cytosol binding proteins. Linoleic acid was solubilized in a 2 mM taurocholate solution which did not compromise the functional integrity of the vesicles. Linoleic acid uptake in the range of 1 to 100 μM followed passive diffusion kinetics. Time course study showed that linoleic acid uptake reached maximal levels during the initial 15 seconds. Although the amount of linoleic acid accumulated in the vesicles diminished over the next 30 minutes, the molar quantity was still twentyfold higher than that of D‐glucose (6.5 vs 0.33 nmol/mg protein). Uptake of D‐glucose by the vesicles demonstrated typical osmotic responsiveness. We found no osmotic effect on linoleic acid uptake. Hypotonic lysis of membrane vesicles loaded with linoleic acid released 40% of the fatty acid. We concluded that a major portion of the accumulated fatty acid was bound to or incorporated into the membrane itself while ca. 40% did traverse the membrane and accumulated in the intravesicular space as nonmicellar aggregates. The known inhibitors of anion transport, diisothiocyanatostilbene and isothiocyanatostilbene did not change the transport of linoleic acid. We conclude that, in the absence of an unstirred layer or cytosol proteins, linoleic acid transport at up to 100 μM concentration is passive with rapid accumulation both by the cell membrane and the lumen of vesicles.
Incorporation oftrans‐8‐ andcis‐8‐octadecenoic acid isomers in human plasma and lipoprotein lipids
Authors: Emken E. A. , Adlof R. O. , Rohwedder W. K. , Gulley R. M.
Published: November 2006

Mixtures of deuterium‐labeledtrans‐8‐,cis‐8‐ andcis‐9‐octadecenoic acids (8t–18∶1, 8c–18∶1, 9c–18∶1) were fed as triglycerides (TG) to two adult male subjects. Blood samples were collected sequentially over a 48‐hour period. Plasma and lipoprotein lipids were separated by thin layer chromatography and analyzed by gas chromatography‐mass spectroscopy. Results indicate (i) absorption of the 8t‐ and 8c–18∶1 isomers were similar to 9c–18∶1; (ii) the 8t–18∶1 isomer was cleared approximately 30% faster than 9c–18∶1 from plasma TG; (iii) cholesterol ester samples contained 8.4 times less 8t–18∶1 than 9c–18∶1; (iv) incorporation at the 1‐acyl phosphatidylcholine (PC) position was higher for 8t–18∶1 and 8c–18∶1 (2.2 and 1.7 times) than for 9c–18∶1; and (v) discrimination at the 2‐acyl PC position was 4.6‐fold against 8t–18∶1 and 1.3‐fold against 8c–18∶1 compared with 9c–18∶1. Discrimination against uptake of the Δ‐8 isomers in both neutral and phospholipid classes suggests that both 8t‐ and 8c–18∶1 may be preferentially oxidized relative to 9c–18∶1. Except for triglycerides, data for each of the lipid classes from total plasma and individual lipoprotein samples were similar. These data indicate that differences for incorporation and turnover of the 8t‐ and 8c–18∶1 isomers relative to 9c–18∶1 are not substantially influenced by the lipoprotein classes. The maximum isotopic enrichment detected in the chylomicron triglycerides fractions was 60%, which indicates that a substantial amount of endogenous triglycerides was mobilized during absorption of the deuterated fats.
Location of double bonds in fatty acids of fish oil and rat testis lipids. Gas chromatography‐mass spectrometry of the oxazoline derivatives
Authors: Yu Q. T. , Liu B. N. , Zhang J. Y. , Huang Z. H.
Published: November 2006

A new approach to the derivatization and analysis of long chain polyunsaturated fatty acids is described. The method is based on the formation of 2‐alkenyl‐4,4‐dimethyloxazolines by condensation of the starting material with 2‐amino‐2‐methylpropanol. The derivatization method is rapid, efficient and specific with respect to the chain feature of the parent acids. Volatility, comparable with that of the corresponding simple esters, and improved gas chromatographic separation are achieved without difficulty. The derivatives exhibit clear and regular fragmentation patterns that allow easy discrimination of positional isomers and assignment of double bond location in the chain.
Plasma esterase‐1 (ES‐1) activity is increased in rats fed high‐fat diets
Authors: Van Lith H. A. , Meijer G. W. , Van Zutphen L. F. M. , Beynen A. C.
Published: November 2006

The question addressed is whether the amount and type of dietary fat affects esterases in plasma. Rats were fed semipurified diets containing 2.0 to 19.4% (w/w) of fat in the form of coconut fat or corn oil. Fat was added to the diets at the expense of isocaloric amounts of carbohydrates. Plasma total esterase activities measured with 4‐nitrophenylacetate as substrate were slightly increased with increasing fat intakes. However, an increase in fat concentration of the diet was associated with a pronounced increase in the activity of the so‐called ES‐1 isozyme in plasma. ES‐1, which represents very little plasma total esterase activity, was quantified densitometrically as the high‐mobility, anodal esterase band on polyacrylamide gel electrophoresis. The positive association between amount of dietary fat and ES‐1 activity was identical for coconut fat and corn oil.
Recent advances in the purification, characterization and structure determination of lipases
Authors: Antonian Edna
Published: November 2006

Recently, lipases have been purified from mammalian, bacterial, fungal and plant sources by different methodologies. Purified lipases subsequently have been characterized for molecular size, metal binding capabilities, glycoside and phosphorus contents, and substrate specificities. Primary structures of several lipases have been determined either from amino acid or nucleic acid sequences. Lipases sequenced to date share sequence homologies including a significant region, Gly‐X‐Ser‐X‐Gly, that is conserved in all. The Ser residue is suspected to be essential for binding to lipid substrates.
Effect of host sterols on the sterol composition and virulence of a nuclear polyhedrosis virus ofHeliothis zea
Authors: Donald Dorothy L. Mac , Ritter Karla S.
Published: November 2006

The type of sterol in the diet ofHeliothis zea affected not only the sterol composition of the insect larva but also the virulence and/or sterol composition of a single‐nucleocapsid nuclear polyhedrosis virus (HzSNPV). This baculovirus, which was purified by differential and sucrose density gradient centrifugation, had a sterol content of 40 ng per 106 polyhedra. When the sterol composition of HzSNPV was characterized by gas liquid chromatography, reversed phase‐high performance liquid chromatography, mass spectrometry, proton nuclear magnetic resonance spectrometry and/or ultraviolet spectroscopy, the sterols in the virus were similar to those of the host. The HzSNPV isolated from larvae fed Δ5_, Δ0_ or Δ5,7‐sterols contained primarily cholesterol, cholestanol or 7‐dehydrocholesterol, respectively. Changes in the sterol composition of HzSNPV affected its LD50, but not LT50, in larvae containing Δ5‐sterols. The LD50 of virus isolated from larvae containing Δ0_, Δ5_ and Δ7‐sterols decreased from 275,423 to 32,359 to 5,012 polyhedra/larva, respectively. The latter virus was also more virulent than the one that was isolated from larvae containing Δ5,7‐sterol and had an LD50 of 58,884 polyhedra/larva. In contrast, the LD50 of an HzSNPV (Sandoz, Inc.) containing Δ5‐sterol was not affected by the presence of Δ5_, Δ0_ or Δ5,7‐sterols in the tissues of the host (1,413; 1,288 and 355 polyhedra/larva, respectively). The results of this study indicate that the sterol composition ofH. zea can affect the sterol composition of HzSNPV and therefore may affect the ability of this biological control agent to control its economically important insect host.
Lipid composition of normal male rat islets
Authors: Díaz Graciela B. , Cortizo Ana Maria , Garciía María Elisa , Gagliardino Juan José
Published: November 2006

Lipid composition was studied in fresh isolated isolets from normal male rats. Extractable lipids represent 1856 μg per mg islet protein. In such extracts, phospholipids and neutral lipids reprsent 13.5% and 86.5%, respectively. Phosphatidylcholine (45.8%) and phosphatidyl‐ethanolamine (20.6%) were the major components of the phospholipid fraction, and phosphatidylinositol (8.9%) was the minor component. Esterified cholesterol (38.5%), cholesterol (25.5%) and free fatty acids (24.4%) were the major components of the neutral lipid fraction. Fatty major components of the neutral lipid fraction. Fatty acids esterified to phospholipids account for 619.7 pmol/islet, and, 2710 pmol/islet were esterified to neutral lipids. In the phospholipid fraction, saturated and unsaturated fatty acids were in a similar proportion. Conversely, in the neutral lipids, two‐thirds of the fatty acids were unsaturated. The ω6 family was the main component of the phospholipid unsaturated fatty acids. In the ω6 and ω3 families, the long‐chain fatty acids represent the main components. In the neutral lipid fraction, a different percentage of each family was found: ω3>ω6>ω9. The long‐chain polyunsaturated fatty acids were also predominant species in the ω6 and ω3 families. Further studies on the lipid composition of islets, obtained from rats with normal and altered islet functions, could provide new insights into the knowledge of the mechanism of insulin secretion.
New oxidation products of 2,2,5,7,8‐pentamethyl‐6‐chromanol
Authors: Suarna Cacang , Sumarno  , Nelson Derek , Southwell‐Keely Peter T.
Published: November 2006

Oxidation of the α‐tocopherol model compound 2,2,5,7,8‐pentamethyl‐6‐chromanol (1) byt‐butyl hydroperoxide in chloroform, to which an alcohol has been added, produces 5‐alkoxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanol as the major product. In the present study,1 was oxidized byt‐butyl hydroperoxide in water‐saturated chloroform to determine whether water would influence product formation in the same way as alcohols.

In addition to the usual products of oxidation such as 2‐(3‐hydroxy‐3‐methylbutyl)‐3,5,6‐trimethyl‐1,4‐benzoquinone (9), 5‐formyl‐2,2,7,8‐tetramethyl‐6‐chromanol (11), the spirodimer and spirotrimer of1, three new products have been identified−2,2,7,8‐tetramethyl‐5‐(2,2,5,7,8‐pentamethyl‐6‐chromanoxy)methyl‐6‐chromanol (4), 5‐hydroxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanol (5) and 3‐hydroxymethyl‐2‐(3‐hydroxy‐3‐methylbutyl)‐5,6‐dimethyl‐1,4‐benzoquinone (7).
Molecular species of mycolic acid subclasses in eight strains ofMycobacterium smegmatis
Authors: Baba T. , Kaneda K. , Kusunose E. , Kusunose M. , Yano I.
Published: November 2006

Thin layer chromatographic and gas chromatographic separation and mass spectrometric identification of mycolic acid subclasses and molecular species from eight strains ofMycobacterium smegmatis were established. Two major adjacent spots and a lower minor one were detected on silica gel thin layer chromatograms of methyl esters. The most abundant subclass showing the highest Rf value on TLC was that of α‐mycolic acids (M1), the second was that of α′‐mycolic acids (M1′) a shorter homologue than α‐mycolates, and the third was the hydroxy mycolic acids (M4) derived from epoxy mycolic acids. They were identified by gas chromatography‐mass spectrometry as their trimethylsilylether derivatives. α′‐Mycolic acids were monoenoic acids ranging from C60 to C66 and possessing an α‐unit of C24∶0. Such profiles of α′‐mycolic acids were common in eight strains. α‐Mycolates were dienoic acids ranging from C75 to C79 and possessing an α‐unit of C24∶0. In most strains, the major molecular species of α‐mycolates were odd‐carbon‐numbered, centering at C77 and C79, possessing a methyl branch in the even‐carbon‐numbered straight chain. The average carbon number of α‐mycolates, from seven strains examined, was about 78, but that of the Takeo strain was 76.3. The profiles of epoxy mycolic acid molecular species composition from eight strains ranging from C75 to C81 were very similar to their M1 subclass profiles.
Fatty acids as biological markers for bacterial symbionts in sponges
Authors: Gillan Francis T. , Stoilov Ivan L. , Thompson Janice E. , Hogg Ronald W. , Wilkinson Clive R. , Djerassi Carl
Published: November 2006

Analyses of fatty acids with carbon numbers between C12 and C22 are reported for five Great Barrier Reef sponges. These analyses indicate that phototrophic cyanobacterial symbionts (blue‐green algae) present in three of the sponges are chemically distinct, whereas the other two sponges do not contain cyanobacterial symbionts. All the sponges contain other, nonphototrophic bacteria. The fatty acid analyses indicate that the nonphototrophic bacterial populations present in the different sponges are distinct in both their chemical compositions and their abundances. Nonphototrophic bacteria are estimated to account for between 60 and 350 μg/g (extractable fatty acids:tissue wet weight), whereas cyanobacteria account for between 10 and 910 μg/g. One sponge (Pseudaxinyssa sp.) contains a relatively large amount of the isoprenoid acid, 4,8,12‐trimethyltridecanoic acid; this acid is presumed to be derived from phytol, a degradation product of chlorophyll. This sponge also contains relatively large amounts of the nonmethylene interrupted fatty acid, octadeca‐5,9‐dienoic acid. Analyses of interior and cyanobacteria‐rich surface tissues of this sponge indicate that these two acids are probably not associated with the symbiotic cyanobacteria.
Rapid separation of neutral lipids, free fatty acids and polar lipids using prepacked silica sep‐Pak columns
Authors: Hamilton James G. , Comai Karen
Published: November 2006

A method is described for the separation of neutral lipid, free fatty acid and polar lipid classes using small (600 mg), prepacked silica Sep‐Pak columns. Combinations of hexane and methyltertiarybutylether were used to progressively elute cholesteryl ester first then triglyceride from the column. After column acidification, fatty acids were eluted followed by cholesterol. Recoveries of these lipids were 96% or greater. Polar lipids were eluted from the column using combinations of methyltertiarybutylether, methanol and ammonium acetate. Phospholipid classes could not be separated completely from each other. Phosphatidylethanolamine and phosphatidylinositol eluted together, whereas the more polar phosphatidylcholine, sphingomyelin and lysophosphatidylcholine were eluted as a second fraction. Recoveries of each phospholipid was greater than 98%.
Separation of neutral lipid, free fatty acid and phospholipid classes by normal phase HPLC
Authors: Hamilton James G. , Comai Karen
Published: November 2006

Normal phase high performance liquid chromatography methods are described for the separation of neutral lipid, fatty acid and five phospholipid classes using spectrophotometric detection at 206 nm. Separations were accomplished in less than 10 min for each lipid class. A mobile phase consisting of hexane/methyltertiarybutylether/acetic acid (100∶5∶0.02) proved effective in separating cholesteryl ester and triglyceride with recoveries of 100% for radiolabeled cholesteryl oleate and 98% for radiolabeled triolein. Free fatty acid and cholesterol were separated by two different mobile phases. The first, hexane/methyltertiarybutylether/acetic acid (70∶30∶0.02) effectively separated free fatty acids and cholesterol, but did not separate cholesterol from 1,2‐diglyceride. A mobile phase consisting of hexane/isopropanol/acetic acid (100∶2∶0.02) effectively separated free fatty acid, cholesterol, 1,2‐diglyceride and 1,3‐diglyceride. Recoveries of oleic acid and cholesterol were 100% and 97%, respectively. Five phospholipid classes were separated using methylteriarybutylether/methanol/aqueous ammonium acetate (pH 8.6) (5∶8∶2) as the mobile phase. The recoveries of phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin and lysophosphatidylcholine were each greater than 96%.
Phytophthorols‐novel lipids produced byPhytophthora cactorum
Authors: David Nes W.
Published: November 2006

Lipid‐phytophthorols are a series of saturated and unsaturated odd chain fatty alcohols (C17–C21) esterified to myristic acid (14∶0) with each possessing two hydroxyl functions in a 1,2‐diol relationship centered toward the ester terminus. They have been identified, and their biosynthetic relationship to other fatty acid and alcohols produced byPhytophthora cactorumhave been determined. Because phytophthorols are crystalline materials and elute in TLC and HPLC with sterols, an architectural function is implied. In the absence of cholesterol, dietary phytophthorol failed to induce reproduction.
Lysophosphatidylcholine accumulation in the ischemic canine heart
Authors: Kinnaird Anne A. A. , Choy Patrick C. , Man Ricky Y. K.
Published: November 2006

The production of cardiac arrhythmias and the elevation of lysophosphatidylcholine level in the ischemic myocardium have been well‐documented in a number of studies. However, the relationship between the production arrhythmias and the elevation of tissue lysophosphatidylcholine level was not reported. In this study, the lysophosphatidylcholine level and the occurrence of cardiac arrhythmias in the ischemic canine heart were monitored. A temporal relationship between the accumulation of lysophosphatidylcholine and the occurrence of arrhythmias was established after five hr of ischemia. A significant elevation of lysophosphatidylcholine was detected at three hr of ischemia without the occurrence of arrhythmias. The results indicate that cardiac arrhythmias did not cause the elevation of lysophosphatidylcholine and if lysophospholipids are causally related to the arrhythmias that a critical level of the lysophospholipid must accumulate in order to elicit electrophysiological alterations.
Subcellular distribution of disaturated phosphatidylcholine in developing rabbit lung
Authors: Oulton M. , Dolphin M.
Published: November 2006

To determine the subcellular distribution of disaturated phosphatidylcholine (DSPC) in lung tissue during perinatal development, fetal rabbits at 24, 26, 28 and 31 (term) days gestation and newborns were studied. Following alveolar lavage, fractions enriched in nuclei‐cellular debris, mitochondria, microsomes, surfactant (lamellar bodies) and cytosol were prepared from the residual tissue homogenate, and their DSPC content was determined. The DSPC content of the unfractionated residual lung tissue homogenate progressively and significantly increased during fetal development, rising from 9.09±0.91 to 17.45±2.88 mg/g dry lung between 24 days gestation, and term. Between 24 and 26 days gestation the overall increase in tissue DSPC was due to a two‐fold increase in the mitochondrial, microsomal and cytosolic pools. Lamellar bodies were first isolable at 26 days gestation. The DSPC content of this fraction increased six‐fold (from 0.10±0.02 to 0.67±0.15 mg/g dry lung) between 26 and 28 days gestation and a further seven‐fold (to 4.63±1.06 mg/g dry lung) by term, accounting for the overall increase in the tissue homogenate value during this time period. By the first postnatal day, microsomal and cytosolic DSPC increased another two‐fold, but no significant change occurred in the other subcellular fractions. Alveolar lavage DSPC progressively increased over the time period studied. While there was no change in the lamellar body DSPC/total PC ratio during fetal development, each of the mitochondrial, microsomal and cytosolic ratios decreased between days 26 and 28 of gestation and then increased at term. Our results indicate that in addition to the pulmonary surfactant, for which DSPC is often used as a marker, other subcellular organelles contain significant DSPC pools that undergo dynamic changes in size during perinatal development.
Differential utilization of long chain fatty acids during triacylglycerol depletion. I. Rat heart after ischemic perfusion
Authors: Cunnane S. C. , Karmazyn M.
Published: November 2006

Rat hearts were perfused with Krebs‐Henseleit buffer for 90 min according to the Langendorff procedure. Normoxic perfusion for 90 min resulted in minor changes in fatty acid composition and a decrease in residual heart triacylglycerol to 60% of preperfusion values. When the protocol included 30 min of slow perfusion‐induced ischemia, the hearts were observed to be depleted of 89% of their initial triacylglycerol content. The triacylglycerol fatty acid composition (mg %) remained similar after compared to before perfusion except for a 121 mg % increase in stearic acid and a 225 mg % increase in arachidonic acid. The percentage composition of both fatty acids was significantly inversely correlated with the amount of triacylglycerol remaining in the heart after perfusion. Postperfusion, arachidonic acid and stearic acids were present at nearly 1∶1 in the residual heart triacylglycerol, suggesting that a common mechanism may be involved in the selective retention of these fatty acids by the heart.
Fluorescence formation from hydroperoxide of phosphatidylcholine with amino compound
Authors: Iio Toshihiro , Yoden Kazuaki
Published: November 2006

The hydroperoxides of methyl linoleate, 1‐palmitoyl‐2‐linoleoyl‐phosphatidylcholine and trilinolein each produced similar fluorescent substances through reaction with amino compounds after decomposition by heme methyl ester. Fluorescent substances formed from methyl linoleate with 1‐aminopentane revealed characeristic fluorescence peaks on HPLC, while those obtained from 1‐palmitoyl‐2‐linoleoyl‐phosphatidylcholine and trillinolein were not eluted under the same conditions. However, when both of these fluorescent substances were transesterified to methyl ester, the same fluorescence peaks were observed. This result suggests that fluorescent substances formed from oxidized membrane lipids with amino compounds remain attached to phospholipids without being released from their glycerol backbone.
Effects of dietary peanut oil on serum lipoprotein patterns of rats
Authors: Miller Josephine , Worthington R. E.
Published: November 2006

Oils prepared from two varieties of peanuts and from a hybrid corn having linoleic acid concentrations substantially different from the respective commercial oils were compared with commercial oils for their effects on serum lipids of weanling female rats. In the first experiment, serum lipid patterns appeared to reflect linoleic acid content of the dietary oil. However, with a longer feeding period in the second experiment, serum lipid patterns were determined by the plant source of the dietary oil rather than its linoleic acid content; all peanut oils differed from both corn oils in their physiological effects. Diets containing triglyceride, hydrocarbon and sterol fractions obtained by liquid chromatography of peanut and corn oils were fed to female rats. The data provide no evidence that the hydrocarbon or sterol fractions of peanut oil are responsible for its unusual atherogenicity when fed as the sole fat source or that similar fractions from corn oil are protective against the effects of peanut oil.
Biological effects of fish oils in relation to chronic diseases
Authors: Carroll Kenneth K.
Published: November 2006

The low incidence of cardiovascular disease in Greenland Eskimos appears to be due to their high intake of seal, whale and fish. The lipids of these marine animals lower serum triglyceride and cholesterol levels and help to prevent blood clotting. The latter effect has been related to a change in the balance of prostacyclin and thromboxane as a result of replacing n‐6 polyunsaturated fatty acids in the body by n‐3 polyunsaturated fatty acids present in marine lipids. Dietary fish oils have also been shown to inhibit development of mammary, pancreatic, intestinal and prostatic tumors in experimental animals. This effect may likewise be due to changes in the production of prostaglandins or related compounds. The involvement of prostaglandins and leukotrienes in immune responses has led to studies on the effects of fish oil on various chronic diseases associated with abnormalities of the immune system. Some of these diseases, such as multiple sclerosis and psoriasis, are also relatively uncommon in Eskimos. Preliminary results of these studies are encouraging, but more work is required to assess the usefulness of dietary fish oils in treatment of these diseases. In addition to their apparent therapeutic value, n‐3 fatty acids are considered essential dietary components since they cannot be synthesized in the body and appear necessary for normal vision and probably other body functions.
Comparative study of the blood pressure effects of four different vegetable fats on young, spontaneously hypertensive rats
Authors: Hoffmann P. , Block H. ‐U. , Beitz J. , Taube Ch. , Forster W. , Wortha P. , Singer P. , Naumann E. , Heine H.
Published: November 2006

Following the suckling period, four groups of male four‐week‐old spontaneously hypertensive rats (SHR) were fed semisynthetic diets with 14% (by weight) of either sunflower seed oil [46% 18∶2(n−6); linoleic acid (LA)‐rich], linseed oil [62.5% 18∶3(n−3)+12.9% 18∶2(n−6); α‐linolenic acid (LNA)‐rich], evening primrose oil [9.2% 18∶3(n−6)+71% 18∶2(n−6); γ‐linolenic acid (LNA)‐rich] or hydrogenated palm kernel fat [1.5% 18∶2(n−6); polyunsaturated fatty acid (PUFA)‐deficient], respectively, up to an age of 18 wk. All diets enriched with PUFA provoked an attenuation of hypertension development. The effect was lowest in the LA‐rich group and highest in the γ‐LNA‐rich group. Differences in fatty acid composition of renal phospholipids between groups reflect the fatty acids present in the respective dietary fats. Renomedullary production of PGF2α was significantly reduced in α‐LNA‐rich and slightly diminished in γ‐LNA‐rich fed rats. Aortic formation of 6‐keto‐PGF1α and TXB2 was increased in animals fed the γ‐LNA‐rich diet. Thus, the attenuation of hypertension development cannot be explained only by changes in prostanoid formation. Other mechanisms possibly involved should be pursued.
Intestinal absorption and fecal excretion of 5,6α‐epoxy‐5α‐cholesta‐3β‐ol by the male wistar rat
Authors: Bascoul J. , Domergue N. , Mourot J. , Debry G. , de Paulet A. Crastes
Published: November 2006

The intestinal absorption of 5,6α‐epoxy‐5α‐cholesta‐3β‐ol, an oxysterol formed by cholesterol autoxidation, has been evaluated in the male Wistar rat. Measurement of the14C/3H ratio in the serum (by the method of Zilversmit and Hugues) and in the feces showed that a large proportion of the epoxide was absorbed. Epoxide clearance from the blood was very rapid, but its excretion in the stool continued for several days, corresponding to the fraction of the epoxide stored in the animal.
Changes in lipids in liver and serum of rats fed a histidine‐excess diet or cholesterol‐supplemented diets
Authors: Ohmura Eri , Aoyama Yoritaka , Yoshida Akira
Published: November 2006

The influence of dietary excess (5%) L‐histidine on serum and liver lipids was examined in rats. Feeding a histidine‐excess diet for 3, 6, 14 or 30 days caused growth retardation, hepatomegaly and decreased liver lipids throughout the period of the experiment. Hypercholesterolemia was observed after feeding a histidine‐excess diet for 6 days; then serum cholesterol continuously increased for 30 days. Serum triglyceride on day 30 in rats fed the histidine‐excess diet showed a significant decrease compared to rats fed the basal diet. Serum phospholipids of rats fed the histidine‐excess diet for 7 or 14 days showed a significant increase compared to rats fed the basal diet. When rats were fed a basal, histidine‐excess or cholesterol‐supplemented diet (0.5% and 1.0% cholesterol) for 6 days, the distribution of serum high density (HDL), low density (LDL) and very low density lipoprotein cholesterol in rats fed the histidine‐excess diet was similar to that of rats fed the basal diet, whereas LDL‐cholesterol increased and HDL‐cholesterol decreased in rats fed the cholesterol‐supplemented diet.
Regulation of cholesterol synthesis in isolated epithelial cells of human small intestine
Authors: Sviridov D. D. , Safonova I. G. , Talalaev A. G. , Repin V. S. , Smirnov V. N.
Published: November 2006

We have investigated the regulation of cholesterol synthesis in isolated human small intestine epithelial cells (enterocytes). It was established that the amount of cholesterol synthesized increased linearly with the incubation time and the number of cells in the incubation mixture; the synthesis was suppressed by 7‐ketocholesterol. Cholic, dehydrocholic, chenodeoxycholic, glycocholic, taurocholic, taurochenodeoxycholic and taurodeoxycholic acids inhibited cholesterol synthesis in enterocytes to different degrees in a dose‐dependent manner. Lithocholic acid enhanced the rate of cholesterol synthesis. Deoxycholic acid, methyl ester of cholic acid and cholesterol did not affect the process. No bile acids tested, with the exception of taurodeoxycholic acid, affected fatty acid synthesis in enterocytes. Most bile acids also decreased cholesterol synthesis in cultured human skin fibroblasts. The results obtained make it possible to postulate that cholesterol synthesis in human enterocytes may be subject to a complex regulation by bile acids.
Species differences in lipid peroxide levels in lung tissue and investigation of their determining factors
Authors: Arakawa Kenji , Sagai Masaru
Published: November 2006

Marked species differences in thiobarbituric acid reactant value (TBA value) in normal lung tissue of five species of animals were found. The order of the values was mouse > hamster > rat > guinea pig > rabbit, and the value for mice was 3.6 times higher than that for rabbit. The vitamin E (VE) and nonprotein sulfhydryls (NPSH) contents in lungs varied widely among the five animal species. Species differences were also observed on polyunsaturated fatty acid composition in lung phospholipids. The peroxidizability index (PI), which shows the relative rate of peroxidation reaction, was calculated from the composition ratio and the reactivity of each polyunsaturated fatty acid, and the PI was found to be significantly correlated to the TBA value in lungs (r=0.853, p<0.001). The PI value was normalized by the contents of VE and/or NPSH. Finally, the log‐value of PI, normalized by the log values of the reciprocals of VE and NPSH, log(PI/VE·NPSH), showed the highest correlation coefficient (r=0.907, p<0.001). Normalization by the activities of antioxidative protective enzymes in lungs did not show any significant correlation against TBA value. These results suggest that TBA value as an index of lipid peroxides in the lungs of animals may be regulated mainly by the contents of VE and NPSH, the composition ratio and the reactivity of each polyunsaturated fatty acid in lung phospholipid fraction.
Limitations of the method using peroxidase activity of hemoglobin for detecting lipid hydroperoxides
Authors: Shibata Selma Setsu , Terao Junji , Matsushita Setsuro
Published: November 2006

The method using peroxidase activity of hemoglobin (Hb) for the determination of lipid peroxides was examined by using pure methyl linoleate hydroperoxides, trilinoleoylglycerol hydroperoxides and egg yolk phosphatidylcholine hydroperoxides as substrates and tetramethyl benzidine as electron donor for the peroxidase reaction of Hb. The reactivities of these substrates were quite varied. Furthermore, some electron donors were tested for peroxidase activity of Hb, but none showed a complete reduction of methyl linoleate hydroperoxides. From these results, it seems the Hb method needs to be carefully applied to biological materials that contain mixtures of different types of lipid classes.
Effects of dietary fiber in Vervet monkeys fed “Western” diets
Authors: Kritchevsky David , Davidson Larry M. , Scott Daniel A. , Van der Watt J. J. , Mendelsohn Dennis
Published: November 2006

Male Vervet monkeys (7/treatment) were fed a “Western” diet containing 46.2% calories as fat, 39.8% as carbohydrate and 14.0% as protein. The diet was augmented with 10% cellulose or 10% pectin. A third (control) group of seven monkeys was fed a commercial ration augmented with fruit and bread. After 34 weeks, serum cholesterol levels were elevated significantly in the two test groups compared with the controls but there was no difference between the two fiber‐fed groups. Serum triglycerides were unaffected. Liver cholesterol levels were the same in all three groups but liver triglyceride levels were lower in the monkeys fed cellulose. Biliary lipids were similar in all three groups as were the calculated lithogenic indices. The average aortic sudanophilia (percent of total area) in the three groups was cellulose, 10.6±2.5; pectin, 8.1±2.5; and control, 1.1±0.4. One animal in each of the groups fed “Western” diet exhibited an atherosclerotic plaque. The results indicate that there is no difference between pectin and cellulose with regard to their effects on either lipidemia or aortic sudanophilia in Vervet monkeys fed a Western‐type diet.
Hypocholesterolemic action of chitosans with different viscosity in rats
Authors: Sugano Michihiro , Watanabe Shuji , Kishi Akihiro , Izume Masato , Ohtakara Akira
Published: November 2006

The relationship between hypocholesterolemic efficacy and average molecular weight of chitosan was studied in rats fed a cholesterol‐enriched (0.5%) diet. Several chitosan preparations with a comparable degree of deacetylation but differing widely in average molecular weight, as demonstrated by viscosity, almost completely prevented the rise of serum cholesterol at the 5% dietary level. At the 2% level, chitosans with viscosities at both extremes exerted a comparable cholesterol‐lowering action. The glucosamine oligomer composed mainly of three to five aminosugar residues was not effective. The results indicate that the hypocholesterolemic action of chitosans is independent of their molecular weight within the tested viscosity range.
Testing a short‐term feeding trial to assess compositional and histopathological changes in hearts of rats fed vegetable oils
Authors: Kramer J. K. G. , Farnworth E. R. , Thompson B. K. , Corner A. H.
Published: November 2006

Male, female and castrated rats, three wk of age, were fed a low‐fat diet for 14 wk followed by high‐fat diets (20% by weight) for one wk containing graded levels of erucic acid from 1 to 50%, to evaluate the effect of short‐term feeding and interaction of male sex hormones on formation of heart lesions. Some rats within each group were returned to the low‐fat diet for one wk after the test period. For comparison, one group of three‐wk‐old male rats was fed the high fat 50% erucic acid diet for 15 wk. Erucic acid depressed growth rate and food consumption and increased cardiac lipidosis and triglycerides proportional to the erucic acid content of the diet. There were no sex differences, and the effects disappeared once rats were returned to the low‐fat diet for one week. There was a significance (P<0.05) in the incidence of myocardial necrosis among male rats fed increased levels of erucic acid for one week, but the response was not linear to the increase in dietary erucic acid. Furthermore, the response was much less than in males fed the 50% erucic acid diet continually for 15 weeks. These results suggest that the short‐term model is not a suitable substitute for the long‐term feeding trial to test the cardiopathogenicity of a vegetable oil. The significantly lower incidence in myocardial lesions in female and castrated male rats compared with male rats suggests involvement of sex hormones. However, the process appears to be long term, since changes in cardiac lipids and their fatty acid pattern between sexes became evident after one wk on diet but was significant only after long‐term feeding.
(3H)Forskolin‐ and (3H)dihydroalprenolol‐binding sites and adenylate cyclase activity in heart of rats fed diets containing different oils
Authors: Alam Syed Q. , Ren Yun‐Fang , Alam Bassima S.
Published: November 2006

The characteristics of the cardiac adenylate cyclase system were studied in rats fed diets containing fish oil (menhaden oil) and other oils. Adenylate cyclase activity generally was higher in cardiac homogenates and membranes of rats fed diet containing 10% menhaden oil than in the other oils. The increase in enzyme activity, especially in forskolin‐stimulated activity, was associated with an increase in the concentration of the [3H]forskolin‐binding sites in cardiac membranes of rats fed menhaden oil. The β‐adrenergic receptor concentration was not significantly altered although the affinity for [3H]dihydroalprenolol‐binding was lower in membranes of rats fed menhaden oil than those fed the other oils. ω‐3 fatty acids from menhaden oil were incorporated into the cardiac membrane phospholipids. The results suggest that the observed increase in myocardial adenylate cyclase activity of rats fed menhaden oil may be due to an increase in the number of the catalytic subunits of the enzyme or due to a greater availability of the forskolin‐binding sites.