bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical and Swelling Properties of Spray‐Dried Powders made from Starch and Poly(vinyl alcohol)
Authors: Jansson Agneta , Järnström Lars , Rättö Peter , Thuvander Fredrik
Published: November 2006

The aim of this study was to investigate whether starch and poly(vinyl alcohol) could be compatible in a powder for coating. Free films of a mixture of the polymers were produced by casting and investigated with respect to their mechanical properties and moisture uptake. The moisture uptake was substantially higher when glycerol was added and the glycerol‐containing films had a lower failure stress under tension than the corresponding glycerol‐free films. At glycerol levels of 20 wt% or above, the glycerol content resulted in a high strain to failure. Dry powders with and without glycerol were made from the starch/poly(vinyl alcohol) solutions by spray drying. The powders were investigated by differential scanning calorimetry (DSC), to determine the degree of physical ageing or crystallinity. All powders showed a broad peak indicative of the melting of crystals at 100–150°C in the first scan, but this peak disappeared almost completely after rapid cooling. The glycerol‐free powder showed a small endothermic peak at about 45°C, indicating physical ageing of the powders during storage. Suspensions of the powders in a liquid plasticiser (glycerol or poly(ethylene glycol)) showed a sharp increase in storage modulus at a certain temperature, indicating the onset of swelling. The observed swelling meant that some of the powders are good candidates for plastisol coatings.
Morphology and Microstructure of Maize Starches with Different Amylose/Amylopectin Content
Authors: Chen Pei , Yu Long , Chen Ling , Li Xiaoxi
Published: November 2006

The morphology and microstructure of maize starches with different amylose/amylopectin ratios (waxy: 0/100; normal maize: 23/77; Gelose 50: 50/50; Gelose 80: 80/20) were studied by microscopy with ordinary and polarized light, scanning electron microscopy (SEM) and X‐ray diffraction (XRD). Generally, the granules of the amylopectin‐rich starches were more regular in shape than those of the amylose‐rich starches, but the surfaces of the amylose‐rich starches were smoother than those of the amylopectin‐rich starches. The birefringence and particle size of the granules were waxy > normal maize > G50 > G80, which also corresponds with the trend of molecular weight. Waxy and normal maize starches showed typical A‐type patterns, while G50 and G80 show B‐type patterns. Crystallinity increases with increasing the amylopectin content.
Peculiarities of Starch Cationization with Glycidyltrimethylammonium Chloride
Authors: Bendoraitiene Joana , Kavaliauskaite Rasa , Klimaviciute Rima , Zemaitaitis Algirdas
Published: November 2006

Cationic starch derivatives containing quaternary ammonium groups with high degree of substitution are prepared by reaction of starch with glycidyltrimethylammonium chloride (GTAC) in different reaction media. In aqueous solutions of GTAC along with conventional hydrolysis of epoxy groups, their interaction with chloride ions also takes place. This resulted in formation of hydroxyl ions which accelerate both the hydrolysis of GTAC epoxy groups and can act as the internal catalyst in the reaction of GTAC with starch. Therefore, even in the absence of the external catalyst, cationic starch with a high degree of substitution can be obtained. The autocatalytic reaction of GTAC with starch proceeds more rapidly at higher temperatures but with lower reaction efficiency. Both in the absence of the external catalyst and in the case when sodium alkali is used as a catalyst the reaction of starch with GTAC proceeds only when a particular quantity of “free” water is present in the system. When the NaOH as catalyst is used the reaction efficiency is about 90%. The yield of starch cationization reaction decreases when the quantity of “free” water is twice or thrice higher than required for starch modification to begin.
Inline‐Analyse hoher Präzision an photovoltaischen Schichtsystemen mittels RFA
Authors: Piltz Joachim
Published: November 2006

Für die effektive Kontrolle von Beschichtungsprozessen ist es erforderlich, online die aktuelle Schichtdicke und Stöchiometrie zu ermitteln. Neue Baugruppen für die energiedispersive Röntgenfluoreszenzanalyse erlauben Messungen an Einzel‐, Mehrfach‐ oder Legierungsschichten im Dickenbereich von 20nm bis 50μm auf unterschiedlichen Substraten (Metalle, Kunststoffe). Es ist notwendig, eine optimale Stahltrassierung zu entwerfen. Erreicht man einen maximalen Messeffekt, kann der statistische Fehler für kurze Messperioden minimiert werden. Die Beachtung der realen Bedingungen eines Beschichtungsprozesses sind wichtig, um die Messparameter über die gesamte Lebensdauer zu garantieren. Ein spezielles Schutzsystem für jede Messeinrichtung muss aufgebaut werden.

Einige Regeln für die Konstruktion und für die Software solcher Systeme werden diskutiert. Ein Messsystem wird vorgestellt.
Three high school after‐school initiatives: Lessons learned
Authors: Barr Sarah , Birmingham Jennifer , Fornal Jennifer , Klein Rachel , Piha Sam
Published: November 2006

Three after‐school initiatives have successfully engaged large numbers of high school youth in activities to increase their school success and allow them to master and apply real world skills. Lessons learned by these afterschool pioneers can inform those interested in serving older youth after school.
Effects of various dietary animal and vegetable proteins on serum and biliary lipids and on gallstone formation in the hamster
Authors: Sullivan Mary Anne , Duffy Anne , Dimarco Nancy , Liepa George
Published: November 2006

The objective of this study was to determine the effects of various dietary animal (casein, bovine albumin and egg albumin) and vegetable (soy, cottonseed and peanut) proteins on serum and biliary constitutents and gallstone formation in the hamster. Eighty‐four hamsters (60±5g) were assigned to either a control group (Purina rat chow) or to one of the 6 experimental groups. Experimental diets contained 20.0% protein. With the exception of hamsters fed egg albumin, gallstone incidence was greater among hamsters fed animal proteins. Hamsters fed egg albumin exhibited a lower concentration of total serum cholesterol and HDL‐cholesterol than most of the other experimental groups. There were no significant differences between experimental groups for either HDL3‐cholesterol concentration or VLDL‐LDL‐cholesterol concentration. Bile acid concentrations within the vegetable protein‐fed groups were significantly higher than within the animal protein‐fed groups. Casein‐ and bovine albumin‐fed hamsters showed a significantly higher percentage of biliary cholesterol in the bile fluid. As the percentage of biliary cholesterol increased, the percentage of bile acids was found to decrease.
Phospholipid composition of guinea pig lung lavage
Authors: Khan Arshad Q. , Sikpi Matthew O. , Das Salil K.
Published: November 2006

Phospholipids from guinea pig lung lavage were analyzed. The total lavage phospholipid content was 2.65+0.67 mg, per gram of lung, which accounted for 85% of the total lipids in lung wash. Phosphatidylcholine (PC) accounted for over 60% of the total phospholipids. The other phospholipids factions, in order of pedominance, were phosphatidylinositol (PI), phosphatidylserine (PS), sphingomyelin (SPH), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and lysophosphatidyl‐choline (LPC). Disaturated phosphatidylcholine (DSPC) comprised 80% of the total PC, and it contained ostly palmitic acid. The DSPC content of the lung lavage fluid per square meter of alveolar surface area was 5.76±0.42 mg.
Effects of high fat diets on the activity of palmitoyl‐CoA hydrolase in rat liver
Authors: Berge Rolf K. , Thomassen Magny S.
Published: November 2006

Palmitoyl‐CoA hydrolase [EC 3.1.2.2.] activity in rat liver was found to be enhanced by high fat diets. Partially hydrogenated marine oil and high‐erucic acid rapeseed oil diets produced a greater increase than a diet containing soybean oil.

With diets containing from 5 to 30% (w/w) of partially hydrogenated marine oil the increase in palmitoyl‐CoA hydrolase activity was similar to the increase observed in peroxisomal β‐oxidation activity (correlation coefficient r=0.94). A positive correlation (r=0.86) also was observed between the activity of palmitoyl‐CoA hydrolase and previously determined levels of long‐chain acyl‐CoA.

The results presented may suggest a common “induction” mechanism for palmitoyl‐CoA hydrolase and peroxisomal β‐oxidation enzymes, possibly exerted through an increased cellular level of long‐chain acyl‐CoA.
Epicuticular waxes of maize as affected by the interaction of mutantgl8 withgl3, gl4 andgl15
Authors: Avato P. , Bianchi G. , Nayak A. , Salamini F. , Gentinetta E.
Published: November 2006

Chemical composition of epicuticular waxes from double mutants of maizegl2gl8, gl3gl8, gl4gl8 andgl15gl8 is compared to that of the wild type and of the single mutants. The wax composition was moderately affected in the double mutants studied. Meanwhile, free fatty acids became a normal class constituent of the waxes. The sites of action of the single mutants as deduced from previous studies are confirmed. The influence ofgl2, gl3 andgl4 on the terminal steps of the chain elongation process ingl2gl8, gl3gl8 andgl4gl8 genotypes is presented and discussed. The study ofgl3gl8 waxes also confirms that the mutantgl3 induces a metabolic defect defiitely different from those ofgl2 andgl4. The pattern of alkanes fromgl15gl8 is unusual, supporting the thesis thatgl15 controls mainly alkane synthesis. However, based on variations induced on wax composition, its manner of action is difficult to account for. Taken together, the available data on single and double mutants affecting wax synthesis in maize suggest that elongases might be heteromeric enzymes.
Dipyridamole inhibits lipid peroxidation and scavenges oxygen radicals
Authors: Iuliano L. , Violl F. , Ghiselli A. , Alessandri C. , Balsano F.
Published: November 2006

Dipyridamole incubatedin vitro in systems which peroxidize fatty acids inhibited arachidonic acid, gammalinolenic acid and linoleic acid peroxidation. In the xanthine‐xanthine‐oxidase system, which produces superoxide anion, dipyridamole inhibited the reduction of cytochrome‐C in a dose‐dependent fashion. In systems generating hydroxyl radicals, dipyridamole reduced deoxyribose degradation in a dose‐dependent manner. The study suggests that dipyridamole inhibits lipid peroxidation, probably by scavening oxygen free radicals.
Effect of dietary n−3 polyunsaturated fatty acids on cholesterol synthesis and degradation in rats of different ages
Authors: Choi Young‐Soon , Goto Shoichiro , Ikeda Ikuo , Sugano Michihiro
Published: November 2006

Male Sprague‐Dawley rats four weeks or eight months of age were fed purified diets containing 10% fat, either as a blend of safflower oil and palm olein (polyunsaturated fatty acids, PUFA, 34%), a blend of linseed oil and palm olein (PUFA, 33%) or sardine oil (PUFA, 33%) for four weeks. In other trials, sterol contents were made equivalent by supplementing cholesterol to a blend of corn oil and palm olein (PUFA, 30%) or phytosterol to sardine oil (PUFA, 30%). Fish oil was hypolipidemic in rats of different ages, but it tended to increase liver cholesterol in adult animals and this was not improved by the addition of phytosterol. The age‐dependent increase in liver cholesterol was not duplicated in rats fed a vegetable fat blend supplemented with cholesterol. At both ages, liver 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase activity was lower in the sardine oil than in the other groups. There were no significant age‐ or diet‐related differences in the activity of liver cholesterol 7α‐hydroxylase. Fecal steroid excretion was comparable in age‐matched rats fed diets supplemented either with cholesterol or phystosterol. Sardine oil reduced the Δ6‐desaturase activity markedly as compared with linseed oil, and age‐dependent reduction of the desaturase activity was observed in all dietary groups examined. Thus, the results showed a specific effect of fish oil on lipid metabolism.
Effect of alcohols on the oxidation of the vitamin E model compound, 2,2,5,7,8‐pentamethyl‐6‐chromanol
Authors: Suarna C. , Southwell‐Keely P. T.
Published: November 2006

The vitamin E model compound, 2,2,5,7,8‐pentamethyl‐6‐chromanol, has been oxidized witht‐butyl hydroperoxide in chloroform in order to simulate in vivo oxidations due to lipid hydroperoxides. In the presence of a variety of alcohols, ranging from methanol to cholesterol, the corresponding 5‐alkoxymethyl‐2,2,7,8‐tetramethyl‐6‐chromanols were formed in fair to good yield and were the major products in each reaction.
Biosynthesis of [14C]arachidonic acid from [14C]linoleate in primary cultures of rat Sertoli cells
Authors: Coniglio J. G. , Sharp J.
Published: November 2006

The conversion of [14C]linoleate to [14C]arachidonate by rat Sertoli cells was established by use of primary cultures. Most of the14C from [1‐14C]linoleate was located in C‐3 of the synthesized arachidonate, indicating that the labeled tetraene had originated largely by elongation and desaturation of the intact labeled substrate rather than by mere addition of14C‐acetate generated by bio‐oxidation of the radioactive substrate to an already existing 18‐carbon precursor. Although a relatively small amount of14C was present in 18∶3ω6 and a relatively large amount of14C was present in 20∶2, it was not possible from these data to establish the relative importance of 20∶2 in the biosynthesis of arachidonic acid in rat Sertoli cells.
Neutral lipid transfer protein does not regulate α‐tocopherol transfer between human plasma lipoproteins
Authors: Granot Esther , Tamir Israel , Deckelbaum Richard J.
Published: November 2006

Vitamin E has no known plasma carrier protein and is transported by plasma lipoproteins. The site of association of vitamin E in the lipoprotein particle and the mode of transfer of vitamin E between plasma lipoproteins have not been ascertained. Since neutral lipids (triglycerides and cholesterol esters) exchange between plasma lipoproteins by processes mediated by neutral lipid transfer protein, we questioned that if vitamin E, a hydrophobic molecule, is carried in the core of the lipoprotein particle then its transfer between plasma lipoproteins may be mediated by neutral lipid transfer protein. Transfer of D‐α(5‐methyl‐3H)tocopherol from in vitro‐labeled human plasma lipoprotein fractions to other plasma lipoproteins was measured under incubation conditions that were designed to yield markedly differing degrees of neutral lipid exchange. Despite the presence of the d>1.21 g/ml lipoprotein‐poor plasma fraction or purified lipid transfer protein that resulted in up to a 10‐fold increase in neutral lipid transfer, vitamin E transfer between very low density lipoproteins, low density and high density lipoproteins remained constant. Even excess amounts of lipid transfer protein, which caused triglyceride transfer between very low density and high density lipoproteins to reach saturation, failed to affect significantly vitamin E transfer. Vitamin E distribution between lipoprotein fractions did correlate with lipoprotein mass ratios. Vitamin E transfer was higher as the protein ratio of acceptor lipoproteins to donor lipoproteins increased. We conclude that vitamin E transfer between lipoproteins is not dependent primarily on neutral lipid transfer protein and is not mediated via neutral lipid transfer.
Genetic variations in serum lipid levels of inbred mice and response to hypercholesterolemic diet
Authors: Aubert Roberte , Perdereau Dominique , Roubiscoul Micheline , Herzog Jeannine , Lemonnier Daniel
Published: November 2006

The serum lipid contents of a number of inbred and congenic strains of mice were measured. There were interstrain variations in each of the lipid fractions in mice fed a normal diet. Male and female C3H mice had the highest total cholesterol level; AKR mice showed the lowest values. Serum phospholipids were correlated well with cholesterolemia. The greatest variations between strains were in the triglyceride levels. There also was significant variation in the high density lipoprotein cholesterol serum levels (from 73–88% of the total cholesterol). The response to a hypercholesterolemic diet (1% cholesterol) was tested in seven inbred strains. All strains showed changes in serum cholesterol and in the proportions of the lipoproteins fractions. There was a large increase in the low density lipoprotein+very low density lipoprotein fractions. Feeding the diet revealed marked interstrain differences in the responses of the serum cholesterol and electrophoretic lipoprotein profiles. The C57BL/6 and B10.D2 strains were hyperresponders to the hypercholesterolemic diet with 71% and 63% of their serum cholesterol in the low density lipoprotein plus very low density lipoprotein fractions, respectively.
Effects of cholesterol feeding to maternal rats on metabolism of cholesterol and bile acids in the dams and their offspring
Authors: Ayaki Yoshikazu , Endo Sachiko , Ogura Yoshio , Ogura Michio
Published: November 2006

The influence of feeding cholesterol to rats during pregnancy and postpartum (from the 11th day of gestation to the third day after delivery) on the serum and hepatic cholesterol levels and on the bile acid composition in the pool and in the liver in relationship to the dams and their pups was examined. The hepatic content of cholesterol in both dam and offspring increased during cholesterol feeding without any changes in serum cholesterol level. In the dams, mainly the esterified cholesterol was increased; in the pups, mainly the free cholesterol was increased. Cholesterol feeding led to a pronounced increase in the pool of β‐muricholic acid and a relative decrease in the lithocholic acid concentration in pregnant rats. In fetal rats, the chenodeoxycholic acid pool was increased by cholesterol intake. The lithocholic acid pool was larger in the postpartum rats fed cholesterol than in the controls, while the concentration of α‐ and β‐muricholic acids was decreased. The neonates of cholesterol‐fed dams had a larger pool of chenodeoxycholic acid but a smaller pool of β‐muricholic acid. These results suggest that the metabolism of cholesterol and of bile acids in dams and their offspring respond differently to cholesterol intake.
Dissolution of cholesterol gallstones by bile acids in the prairie dog
Authors: Cohen Bertram I. , Mosbach Erwin H. , Kuroki Syoji , McSherry Charles K.
Published: November 2006

The effect of chenodeoxycholic acid, ursodeoxycholic acid and hyodeoxycholic acid on gallstone dissolution was studied in the prairie dog. Cholesterol gallstones were found in all animals after feeding a semipurified diet plus 1.2% cholesterol for six wk. Gallstone regression was examined by feeding a chow diet containing the bile acids (chenodeoxycholic acid, ursodeoxycholic acid or hyodeoxycholic acid) alone (30 mg/kg/day) or in combination (chenodeoxycholic acid plus ursodeoxycholic acid) for an additional six wk. Chenodeoxycholic acid was effective in dissolving established cholesterol gallstones (two out of 16 animals still had stones) and cholesterol crystals (six out of 16 animals had crystals); the hydrophilic bile acids, ursodeoxycholic acid and hyodeoxycholic acid, were ineffective in the six‐wk regression study. The lithogenic indices averaged 1.09 at the end of the induction period: all biles became unsaturated with respect to cholesterol after the six‐wk regression period (group 1, 0.82; group 2, 0.66; group 3, 0.81; group 4,0.84; group 5, 0.66). Cholesterol levels in liver, plasma and bile were elevated after the six‐wk induction phase (4.59 mg/g, 610 mg/dl and 0.36 mg/ml, respectively) but returned to near normal levels after the six‐wk regression period. Biliary bile acids contained increased levels of the dietary bile acid administered to each group. This experiment shows that relatively hydrophobic bile acids may be more effective than hydrophilic bile acids for gallstone dissolution during the period studied.
Fatty acid allene oxides. III. Albumin‐induced cyclization of 12,13(S)‐epoxy‐9(Z),11‐octadecadienoic acid
Authors: Hamberg Mats , Hughes Molly A.
Published: November 2006

Recently, corn (Zea mays L.) hydroperoxide dehydrase was found to catalyze the conversion of 13(S)‐hydroperoxy‐9(Z),11(E)‐octadecadienoic acid into an unstable fatty acid allene oxide, 12,13(S)‐epoxy‐9(Z),11‐octadecadienoic acid. This study is concerned with the chemistry of 12,13(S)‐epoxy‐9(Z),11‐octadecadienoic acid in the presence of vertebrate serum albumins.

Albumins were found to greatly enhance the aqueous half‐life of the allene oxide, i.e. 14.1±1.8 min, 11.6±1.2 min and 4.8±0.5 min at 0 C in the presence of 15 mg/ml of bovine, human and equine serum albumins, respectively, as compared with ca. 33 sec in the absence of albumin. Degradation of allene oxide in the presence of bovine serum albumin led to the formation of a novel cyclization product, i.e. 3‐oxo‐2‐pentyl‐cyclopent‐4‐en‐1‐octanoic acid (12‐oxo‐10‐phytoenoic acid, in which the relative configuration of the side chains attached to the five‐membered ring istrans). Steric analysis of the cyclic derivative showed that the compound was largely racemic (ratio between enantiomers, 58∶42).

12‐Oxo‐10,15(Z)‐phytodienoic acid, needed for reference purposes, was prepared by incubation of 13(S)‐hydroperoxy‐9(Z),11(E),15(Z)‐octadecatrienoic acid with corn hydroperoxide dehydrase. Steric analysis showed that the 12‐oxo‐10,15(Z)‐phytodienoic acid thus obtained was not optically pure but a mixture of enantiomers in a ratio of 82∶18.
Composition of mixed octadecadienoates via ozonolysis, chromatography and computer solution of linear equations
Authors: Dutton H. J. , Johnson S. B. , Pusch F. J. , Lie Ken Jie M. S. F. , Gunstone F. D. , Holman R. T.
Published: November 2006

An approach to the analysis of 55 possible nonconjugated positional isomers of octadecadienoic acid is described and tested with mixtures of individual synthetic methyl esters. In the first example, by ozonolysis a sevencomponent mixture consisting ofcis,cis 5,12‐, 6,10‐, 6,11‐, 6,12‐, 7,12‐, 8,12‐, and 9,12‐octadecadienoates was converted to aldehydes, aldehyde‐esters and dialdehydes. These fragments were separated on a 50 m×0.2 mm free fatty acid phase (FFAP) vitreous silica capillary column. Equations for an arbitrarily restricted 12×15 matrix of linear simultaneous equations and a computer solution of the matrix provided the composition of the initial methyl octadecadienoate mixture. The power and significance of this method became apparent with the observation that only two of the seven isomers in the known mixture were resolved as single peaks by state‐of‐the‐art capillary gas chromatography, but all seven were identified and estimated with acceptable error by the ozonolysis‐capillary gas chromatography‐computer procedure. In a generalized approach to the analysis of the 55 possible nonconjugated isomers, a computer program selects the appropriate matrix of linear simultaneous equations based on the aldehyde data supplied by the analyst. Twenty of 21 combinations of seven isomeric esters taken five at a time have been analyzed to assess the efficiency of the method. To illustrate applicability at this stage of development, the method has been used to analyze the diene products of the hydrazine reduction of γ‐linolenic acid and the diene products from the biological desaturation of isomeric monoenes. The possibility of distinguishing geometric and positional isomers of 18∶2 has been opened by the observed separation ofcis‐andtrans‐unsaturated aldehydes and aldehyde‐esters.
Mammary lipoprotein lipase in plasma of cows after parturition or prolactin infusion
Authors: Liesman James S. , Emery Roy S. , Akers R. Michael , Tucker H. Allen
Published: November 2006

Plasma lipase activity from the mammary vein and a tail blood vessel was measured in periparturient Holstein cows treated in one of three ways: control, CB154 (2‐Br‐α‐ergocryptin) or CB154 plus prolactin. CB154 administration decreased basal serum prolactin concentration by 80% and blocked the normal parturient increase of serum prolactin. In CB154 plus prolactin‐treated cows, prolactin was infused continously for six days starting five and eight days prepartum. Plasma lipase activity was not detectable up to 26 hr prepartum in control and CB154‐treated cows or before the start of prolactin infusion in CB154 plus prolactin‐treated cows. After two hr prepartum, plasma lipase activity was detected in all treatments. In CB154 plus prolactin‐treated cows, plasma lipase activity was detected in the presence of high concentrations of serum progesterone four days after the start of prolactin infusion and at least two days before parturition. Plasma lipase activity was four times greater in the mammary vein than in the tail vessel at sampling times at which activity was detected in both vessels. We propose the difference between plasma lipase activity from the mammary vein and tail vessel is due to release of lipoprotein lipase from the mammary gland into blood, and this activity can be induced prepartum by prolactin or at parturition even if the parturient increase in prolactin is suppressed.
Use of a fluorescent radiolabeled triacylglycerol as a substrate for lipoprotein lipase and hepatic triglyceride lipase
Authors: Dousset Nicole , Negre Anne , Salvayre Robert , Rogalle Pierre , Dang Quoc Quan , Douste‐Blazy Louis
Published: November 2006

A fluorescent radiolabeled triacylglycerol has been synthesized by using a fluorescent fatty acid (pyrene decanoic acid) and a radiolabeled oleic acid. This analog of the natural substrate, 1(3)pyrene decanoic‐2,3(1,2)‐dioleoyl‐sn‐glycerol, has been tested as substrate for determining lipoprotein lipase and hepatic triacylglycerol lipase activities in post‐heparin plasma. Optimal conditions for the determination of the two post‐heparin plasma lipases were similar to those using radiolabeled triolein. Using this substrate, both post‐heparin lipases exhibited their characteristic properties (pH optimum and effect of inhibitors) and attacked external ester bonds (1 or 3) containing pyrene decanoic and oleic acids at a similar rate
Diet‐induced type IV‐like hyperlipidemia and increased body weight are associated with cholesterol gallstones in hamsters
Authors: Hayes K. C. , Khosla Pramod , Pronczuk Andrzej
Published: November 2006

Male Syrian hamsters (60–70 g) were fed purified diets containing 5% fat (American Fat Blend) and 15% fiber with or without 0.3% cholesterol (0.86 mg/kcal), for 12 weeks. Hamsters fed the cholesterol‐supplemented challenge diet revealed a major increase in plasma triglyceride between 9 and 12 weeks, whereas plasma cholesterol (which reflected body weight dynamics) increased three‐fold up to nine weeks and plateaued (342±22vs. 122±5 mg/dL). The greatest increases in cholesterol occurred in the very low density lipoprotein (VLDL) and high density lipoprotein (HDL2) fractions. Gallstone incidence was similar (69%vs. 78%) for cholesterol‐supplementedvs. control hamsters, but the type of stones differed. Of the cholesterol‐supplemented hamsters with gallstones, 45% had cholesterol stones and 55% had pigment stones. Only pigment stones were seen in control hamsters. Hamsters with cholesterol stones were 25% heavier and transported most cholesterol in VLDL (33±5%), approximately double that in VLDL of cholesterol‐supplemented hamsters with no stones (19±3%) or cholesterol‐supplemented hamsters with pigment stones (21±3%). Hamsters with pigment stones or no stones (regardless of diet fed) transported the majority of their cholesterol in HDL2 (44%), whereas this figure was only 27% in hamsters that developed cholesterol stones. Thus pigment stones develop routinely in hamsters fed casein‐based purified diets. Adding dietary cholesterol resulted in cholesterol gallstones only in those hamsters that gained the most weight and whose terminal VLDL/HDL cholesterol ratio exceeded 1.0, not unlike the lipoprotein profile of obese humans who develop cholesterol gallstones.
Lipids containing isoricinoleoyl (9‐hydroxy‐cis‐12‐octadecenoyl) moieties in seeds ofWrightia species
Authors: Ahmad Fasih , Schiller Helmut , Mukherjee Kumar D.
Published: November 2006

Composition of lipids in mature seeds ofWrightia tinctoria andWrightia coccinea, which contain large proportions of isoricinoleic acid (9‐hydroxy‐cis‐12‐octadecenoic acid) as constituent fatty acid beside the common long chain fatty acids, is reported. The major classes of acyl lipids in the seeds of the twoWrightia species, identified by chromatographic and mass spectrometric analyses, are found to be triisoricinoleoylglycerol and diisoricinoleoylacylglycerols. Phospholipids and glycolipids contain only small proportions of isoricinoleoyl moieties. Among two possible precursors for the biosynthesis of isoricinoleic acid, 9‐hydroxystearic acid, but notcis‐12‐octadecenoic acid, is detectable in the seed lipids.
(24R‐14α‐methyl‐24‐ethyl‐5α‐cholest‐9(11)‐en‐3β‐ol: A new 14α‐methylsterol fromCucumis sativus
Authors: Akihisa Toshihiro , Shimizu Naoto , Tamura Toshitake , Matsumoto Taro
Published: November 2006

The structure of a new 14α‐methylsterol isolated fromCucumis sativus has been shown to be (24R)‐14α‐methyl‐24‐ethyl‐5α‐cholest‐9(11)‐en‐3β‐ol. Characterization of the 14α‐methyl‐Δ9(11) skeletal structure was undertaken based on the comparison with 14α,24‐dimethyl‐5α‐cholest‐9(11)‐en‐3β‐ol obtained from 24‐methylpollinastanol by acid‐catalyzed isomerization. Isolation and identification of an additional 14α‐methylsterol, 24‐methylene‐pollinastanol, from the plant also is described.
cis‐9,10‐Epoxystearic acid in human leukocytes: Isolation and quantitative determination
Authors: Fahistadius Per
Published: November 2006

Racemiccis‐9,10‐epoxystearic acid was isolated from total lipids of human leukocytes. Identification of the epoxy acid was based mainly on gas liquid chromatographicmass spectrometric analysis and on its chemical conversion intothreo‐9,10‐dihydroxystearic acid. A mass spectrometric method for quantitative determination ofcis‐9,10‐epoxystearic acid using the tetradeuterated compound as internal standard was developed. Using this method, nonstimulated human leukocytes were found to contain 5.1±2.2 μg (SD) ofcis‐9,10‐epoxystearic acid per 109 cells (n=8). More than 90% of the epoxy acid occurred in its esterified form in leukocyte lipids.
Regulation of the metabolism of linoleic acid to arachidonic acid in rat hepatocytes
Authors: Voss Anne C. , Sprecher Howard
Published: November 2006

When 5×106 hepatocytes were incubated for 40 min with from 0.15 to 0.60 mM [1‐14C]linoleic acid, [1‐14C]6,9,12‐octadecatrienoic acid, or [1‐14C]8,11,14‐eicosatrienoic acid, there was a concentration‐dependent acylation of radioactive metabolites into both triglycerides and phospholipids. When the concentration of either [1‐14C]linoleic acid or [1‐14C]8,11,14‐eicosatrienoic acid exceeded 0.3 mM, there was no further increase in the metabolism of either fatty acid to other (n−6) metabolites. When the concentration of [1‐14C]6,9,12‐octadecatrienoic acid exceeded 0.15 mM, there was an apparent substrate‐induced inhibition in its metabolism to 8,11,14‐eicosatrienoic acid. With all three substrates (0.3 mM), there was time‐dependent metabolism to other (n−6) acids. Cells then were incubated simultaneously with 0.3 mM [1‐14C]linoleic acid along with 0.15 to 0.45 mM 6,9,12‐octadecatrienoic acid or 8,11,14‐eicosatrienoic acid. These exogenous nonradioactive (n−6) acids suppressed but did not abolish the conversion of [1‐14C]linoleate to radioactive arachidonate. These findings suggest that some linoleate is converted to arachidonate without intracellular mixing of 6,8,12‐octadecatrienoic or 8,11,14‐eicosatrienoic acids. This hypothesis is supported by the finding that exogenous linoleate did not markedly affect the metabolism of [1‐14C]6,9,12‐octadecatrienoic or [1‐14C]8,11,14‐eicosatrienoic acid by microsomal chain elongating or desaturating enzymes.
Two unsaturated 9R‐hydroxy fatty acids from the cyanobacteriumAnabaena flos‐aquae f. flos‐aquae
Authors: Murakami Nobutoshi , Shirahashi Hideaki , Nagatsu Akito , Sakakibara Jinsaku
Published: November 2006

(9R‐10E,12Z,15Z)‐9‐Hydroxyotadecatrienoic acid and (9R,10E,12Z)‐9‐hydroxyoctadecadienoic acid were isolated from the nitrogen fixing cyanobacteriumAnabaena flosaquae. f. flos‐aquae and characterized as the corresponding methyl esters. This is the first report of the natural occurrence of 9R‐oxygenated fatty acids.
Effect of phosphatidylcholine structure on the adenylate cyclase activity of a murine fibroblast cell line
Authors: Calorini Lido , Mugnai Gabriele , Mannini Antonella , Ruggieri Salvatore
Published: November 2006

To determine which structural characteristics of membrane phospholipids influence adenylate cyclase activity, we measured basal and sodium fluoride‐ or forskolin‐stimulated activity in a murine fibroblast cell line,i.e., Balb/c3T3 cells grown in media supplemented with fetal calf serum (FCS), lipid‐depleted FCS (LD‐FCS) or LD‐FCS complexed with different phosphatidylcholine (PC) molecular species. Cells grown in the presence of LD‐FCS showed a substantial decrease in their basal and NaF‐stimulated adenylate cyclase activities; however, their forskolin‐stimulated activity was not altered, suggesting that the enzyme's catalytic site is not affected by changes in membrane lipids. Media supplemented with different LD‐FCS/PC complexes were shown to prevent the LD‐FCS‐mediated reduction of basal and NaF‐stimulated adenylate cyclase activity to different extents. Addition ofcis‐9‐16∶1/cis‐9‐16∶1,cis‐9‐18∶1/cis‐9‐18∶1 orcis‐9‐18∶1/cis‐9,12‐18∶2sn‐glycerophosphocholine (GPC) completely restored adenylate cyclase activity, whilecis‐11‐18∶1/cis‐11‐18∶1 GPC was not effective and only a partial recovery was observed with 16∶0/16∶0, 16∶0/cis‐9‐18∶1 andtrans‐9‐18∶1 GPC. Considering the structural features of these seven PC molecular species, the findings suggest that an optimal lipid environment is conferred to the enzyme by the presence of thecis double bonds, each located in Δ9 position of the PC acyl chains. The limited effect ofcis‐9‐16∶1/cis‐9‐18∶1 GPC andcis‐9‐18∶1/cis‐9‐16∶1 GPC suggests that an equal length of the terminal hydrocarbon chains extending bevond the Δ9 double bonds is also important. Moreover, complete restoration of adenylate cyclase activity in cells exposed to 16∶0/cis‐9,12‐18∶2 GPC suggests that twocis‐9,12 double bonds located on the same chain are as effective as twocis‐9 double bonds each located on two different chains of PC. As the four double bonds of 16∶0/cis‐5,8,11,14‐20∶4 GPC had no effect, a mere increase in the number of double bonds seems insufficient to build an optimal lipid microenvironment for the enzyme.
Inositol 1,4,5‐trisphosphate accumulation in brain of lithium‐treated rats
Authors: Ishima Yoshio , Fujimagari Michiyo , Masuzawa Yasuo , Waku Keizo
Published: November 2006

The mechanism of action of lithium as a drug for patients with affective disorders was investigated. Three‐week‐old male rats were orally administered 2.7 mEq Li2CO3/kg/d for 1 or 3 wk, and phosphatidylinositol (PI), phosphatidylinositol 4‐phosphate (PIP), phosphatidylinositol 4,5‐bisphosphate (PIP2), inositol phosphate (IP), inositol diphosphate (IP2) and inositol triphosphate (IP3) levels in brain were measured. The levels of IP were increased 1.7 and 2.4 times after 1 wk and 3 wk of lithium administration, respectively, while PI, PIP, PIP2, IP2 and IP3 levels were not altered. IP3 was further fractionated by high‐performance liquid chromatography into I‐1,3,4‐P3 and I‐1,4,5‐P3. In the control rat brain, the relative percentages of I‐1,3,4‐P3 and I‐1,4,5‐P3 were 95.8 and 4.2, respectively. However, after 3 wk of lithium administration, the values were changed to 69.6 and 30.3%, respectively. This increase in the neurotransducer I‐1,4,5‐P3 in the brain may be relevant to the mechanism of action in the lithium treatment of patients with manic‐depressive disorders.
Multiple inhibitory effects of garlic extracts on cholesterol biosynthesis in hepatocytes
Authors: Gebhardt Rolf
Published: November 2006

Exposure of primary rat hepatocytes and human HepG2 cells to water‐soluble garlic extracts resulted in the concentration‐dependent inhibition of cholesterol biosynthesis at several different enzymatic steps. At low concentrations, sterol biosynthesis from [14C]acetate was decreased in rat hepatocytes by 23% with an IC50 (half‐maximal inhibition) value of 90μg/mL and in HepG2 cells by 28% with an IC50 value of 35 μg/mL. This inhibition was exerted at the level of hydroxymethylglutaryl‐COA reductase (MHG‐CoA reductase) as indicated by direct enzymatic measurements and the absence of inhibition if [14C]mevalonate was used as a precursor. At high concentrations (above 0.5 mg/mL), inhibition of cholesterol biosynthesis was not only seen at an early step where it increased considerably with dose, but also at later steps resulting in the accumulation of the precursors lanosterol and 7‐dehydrocholesterol. No desmosterol was formed which, however, was a major precursor accumulating in the presence of triparanol. Thus, the accumulation of sterol precursors seem to be of less therapeutic significance during consumption of garlic, because it requires concentrations one or two orders of magnitude above those affecting HMG‐CoA reductase. Alliin, the main sulfur‐containing compound of garlic, was without effect itself. If converted to allicin, it resulted in similar changes of the sterol pattern. This suggested that the latter compound might contribute to the inhibition at the late steps. In contrast, nicotinic acid and particularly adenosine caused moderate inhibition of HMG‐CoA reductase activity and of cholesterol biosynthesis suggesting that these compounds participate, at least in part, in the early inhibition of sterol synthesis by garlic extracts.
Dietary fat composition and age affect synaptosomal and retinal phospholipid fatty acid composition in C57BL/6 mice
Authors: McGee Carl D. , Greenwood Carol E. , Cinader Bernhard
Published: November 2006

The purpose of this study was (i) to determine whether dietary fat‐induced differences in neural and retinal membranes occur when dietary fat treatment is implemented in aged animals and (ii) to characterize the effect of long‐term differences in dietary fat on neural and retinal membrane composition. For the first objective, young (six‐week‐old) and old (95‐week‐old) mice were randomly assigned to beef tallow (TAL) or soybean oil (SBO) diets for eight weeks. For the second objective, young (four‐week‐old) mice consumed either TAL or SBO diets for 99 weeks. Young and old mice challenged with a change in dietary fat for an eight‐week period showed both diet and age effects on neural and retinal phospholipid fatty acid composition (P<0.05). In addition, significant diet by age interactions were evident. In mice that consumed TAL and SBO diets throughout their life, only retinal phosphatidylethanolamine (PE) 18∶2n−6 and neural phosphatidylserine 22∶5n−6, PE 18∶2n−6 and phosphatidylcholine 18∶2n−6 differed between dietary treatments (P<0.05). Neither the unsaturation index nor the n−6/n−3 ratio was affected by diet. Neural and retinal phospholipid fatty acid composition were responsive to changes in dietary fat even when the treatment was implemented beyond developmental or post‐weanling stages. In contrast, when mice consumed TAL or SBO diets throughout their life, fewer differences in phospholipid fatty acid composition were detected, suggesting that the effect of the dietary treatment was mitigated by aging.
Glucocorticoid and mineralocorticoid hormones depress liver Δ5 desaturase activity through different mechanisms
Authors: de Alaniz Maria J. T. , Marra Carlos Alberto
Published: November 2006

The effects of 11‐deoxycorticosterone and aldosterone on liver Δ5 desaturase activity were examined. Both steroid hormones significantly depressed the conversion of [1‐14C] eicosatrienoic acid to arachidonic acid. However, the mechanism of action of each of these hormones was different. The effect of 11‐deoxycorticosterone was mediated by a soluble protein present in the liver cytosolic fraction. The biological activity of this protein, having a molecular weight lower than 25 kDa, was impaired by trypsin digestion. To determine whether the inhibitory protein was induced through glucocorticoid or mineralocorticoid receptor occupancy, cultured Morris minimal deviation hepatoma cells were pre‐treated with the antiglucocorticoid cortexolone or the mineralocorticoid receptor antagonist spironolactone. The results obtained demonstrated that only glucocorticoid receptor structures were involved in the induction of this regulatory protein. The inhibitory response evoked by aldosterone was mediated by a different mechanism. In the case of aldosterone, the inhibitory action affected the microsomal membranes and was not mediated by a soluble protein messenger.
31P NMR of tissue phospholipids: Competition for Mg2+, Ca2+, Na+ and K+ cations
Authors: Merchant Thomas E. , Glonek Thomas
Published: November 2006

Phosphatidylcholine (PC), phosphatidylethanolamine (PE), ethanolamine plasmalogen (EPLAS), sphingomyelin (SPH), phosphatidylinositol (PI), phosphatidylserine (PS), cardiolipin (CL), phosphatidylglycerol (PG) and phosphatidic acid (PA) were dispersed together in Cs(ethylenedinitrilo)tetraacetic acid‐scrubbed chloroform/methanol solution, and high resolution31P nuclear magnetic resonance spectra were recorded. In separate titration experiments, Mg2+ and Ca2+ were added to the dispersed phospholipid mixture to determine the relative interaction potentials of each of the phospholipids for each of the added cations. The association of cations with individual phospholipids was indicated by31P chemical‐shift changes, signal broadening, signal quenching or a combination of these. The titrations revealed that CL had the highest, and PA the next highest, interaction potential for Mg2+ cations. In contrast, PS and PA had the highest, and CL the next highest, interaction potential for Ca2+. Considering only interactions with Ca2+ ions, the phospholipids can be divided into three distinct groups: PS and PA (high interaction potential); CL, PI and PG (intermediate interaction potential); and EPLAS, PE, SPH and PC (essentially no interaction potential). The two phospholipids with the least interaction potential for either of the alkaline‐earth cations were PC and SPH. Na+ and K+ ion interactions with PA, CL, PI and PG were unique and resulted in positive chemical‐shift changes relative to the chemical shifts in the presence of Cs+ ions. Relative to both Cs+ and K+ ions, chemical shifts in the presence of Na+ ions were deshielded δ>0.1 ppm in the order PA>CL>PI>PG.
Reaction of dipyridamole with the hydroxyl radical
Authors: Iuliano Luigi , Pratico Domenico , Ghiselli Andrea , Bonavita Maria S. , Violi Francesco
Published: November 2006

Dipyridamole [2,6‐bis‐diethanolamino‐4,8‐dipiperidinopyrimido‐(5,4‐d) pyrimidine], a well known platelet aggregation inhibitor, shows powerful hydroxyl radical scavenging activity by inhibiting OH‐dependent salicylate and deoxyribose degradation. Steady‐state competition kinetics experiments with deoxyribose were carried out to evaluate the second‐order rateconstant for the reaction between hydroxyl radical and dipyridamole. OH· radicals were generated either by a Fenton‐type reaction or by X‐ray irradiation of water solutions. A second‐order rate constant k(Dipyridamole+OH·) of 1.72±0.11×1010M−1 s−1 and of 1.54±0.15×1010 M−1 s−1 was measured by Fenton chemistry and by radiation chemistry, respectively. Mannitol was used as an internal standard for hydroxyl radicals in steady‐state competition experiments with deoxyribose. A rate constant k(Mannitol+OH·) of 1.58±0.13×109 M−1 s−1 and 1.88±0.14×109 M−1 s−1 was measured in the Fenton model and in the water radiolysis system, respectively. Both these rate constants are in good agreement with the published data obtained by the “deoxyribose assay” and by pulse radiolysis.
Dexamethasone‐induced alterations in the glycosphingolipids of rat kidney
Authors: Dahiya Rajvir , Brasitus Thomas A.
Published: November 2006

To determine whether glucocorticoids would influence the glycosphingolipid composition of the rat kidney, male albino rats of the Sherman strain were subcutaneously administered dexamethasone (100 μg/100 g body wt/day) or diluent for four days. The compositions of ceramide and of acidic and neutral glycosphingolipids of the kidneys of these animals were then examined and compared. The results demonstrated that dexamethasone administration: 1) increased the content of ceramide and of acidic and neutral glycosphingolipids in kidney; 2) increased the relative percentage of globotriaosyl‐ and globotetraosylceramide, but decreased the relative percentages of glucosylceramide; 3) decreased the relative percentages of GM3 and increased other gangliosides; 4) increased the relative percentages ofN‐glycolylneuraminic acid in GM3; 5) did not appear to influence significantly the long‐chain bases of the major glycosphingolipids; and 6) altered the relative percentages and chain length of the hydroxy and nonhydroxy fatty acids of the major acidic and neutral glycosphingolipids in this tissue. The data show that dexamethasone administration induces quantitative and qualitative changes in the glycosphingolipids of the rat kidney.
Accumulation of (n−9)‐eicosatrienoic and docosatrienoic acids in human fibroblast phospholipids
Authors: Karmiol Soverin , Bettger William J.
Published: November 2006

An essential fatty acid (EFA) deficiency‐like profile of fatty acids has been observed in HF‐1 human skin fibro‐blasts cultured at clonal densities in MCDB 110 and 0.4% fetal bovine serum (FBS). The profile was characterized by an accumulation of 16∶1n−7, 18∶1n−9, 20∶3n−9 and 22∶3n−9, a reduction of n−6 fatty acids and a reduction in total polyunsaturated fatty acids (PUFA). The fatty acid composition of sphingomyelin (SPH), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) was determined and, except for SPH, each displayed an EFA deficiency‐like profile. The triene to tetraene ratio (20∶3n−9/20∶4n−6) ranged from 5.3 in PI to 0.9 in PE. In addition, the highest percentage of 20∶3n−9 was present in the PI and the highest percentage of 22∶3n−9, in PE. Other human fibroblasts (normal, transformed and at different population doubling number levels [PDL] were grown under the same conditions and were found to display triene to tetraene ratios (20∶3n−9/20∶4n−6) in total cellular lipids ranging from 0.7 to 4.5. The accumulation of 20∶3n−9 and 22∶3n−9 is due primarily to the existence of a basal nutrient medium (MCDB 110) that allows for the rapid clonal growth of human fibroblasts at reduced serum levels (0.4%). This culture procedure can be exploited to further elucidate various aspects of lipid metabolism in human fibroblasts.
Phospholipids from the free‐living nematodeCaenorhabditis elegans
Authors: Satouchi Kiyoshi , Hirano Kaoru , Sakaguchi Masamitsu , Takehara Hisaaki , Matsuura Fumito
Published: November 2006

The phospholipid and the fatty chain compositions of diacyl, alkylacyl and alkenylacyl glycerophospholipids of the free‐living nematode,Caenorhabditis elegans, were investigated. The phospholipids were comprised of 54.5% ethanolamine glycerophospholipid (EGP), 32.3% choline glycerophospholipid (CGP), 8.1% sphingomyelin and 5.1% others. The most abundant fatty acid in CGP was eicosapentaenoic acid (20∶5n−3). The fatty acids in CGP were more unsaturated than those in EGP. Alkenylacyl and alkylacyl subclasses accounted for 1.0 and 2.6%, respectively, of CGP and 14.0 and 19.6%, respectively, of EGP. At least 80% of the alkenyl and alkyl groups were 18∶0 chains and the remaining were odd numbered chains. The potential presence of platelet‐activating factor (PAF) was examined by bioassay, but PAF‐like activity was not detected in the extracts of this nematode.