bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of ethoxylated fatty amines. Comparison of methods for the determination of molecular weight
Authors: Lang Russell F. , Parra‐Diaz Dennisse , Jacobs Dana
Published: November 2006

Specific lengths of the fatty and polyoxyethylene chains of ethoxylated fatty amines are critical to their performance in specific applications, and thus the ability to characterize these surfactants accurately is crucial. Normal‐phase high‐performance liquid chromatography (HPLC) and matrixassisted laser desorption ionization‐time of flight (MALDI‐TOF) mass spectrometry methods were developed to determine with accuracy the molecular weight and degree of ethoxylation of ethoxylated fatty amines. Ethoxylated fatty amines were analyzed using these methods, and comparison was made to molecular weight determinations using proton nuclear magnetic resonance (NMR), neutralization equivalent weight, and hydroxyl value methods. Molecular weight results from normalphase HPLC analyses were in very good agreement with MALDI‐TOF results, typically varying less than one ethylene oxide unit. A reversed‐phase HPLC method was developed to determine concentrations of polyethylene glycols (PEG) and fatty homologs. PEG interfered with molecular weight determinations by NMR, neutralization equivalent weight, and hydroxyl value methods. PEG caused no interference with molecular weight determinations by normal‐phase HPLC and MALDI‐TOF methods.
Correlation of fatty acid unsaturation of the major liver mitochondrial phospholipid classes in mammals to their maximum life span potential
Authors: Portero‐Otín Manuel , Josep Bellumunt Maria , Cristina Ruiz Maria , Barja Gustavo , Pamplona Reinald
Published: November 2006

Free radical damage is considered a determinant factor in the rate of aging. Unsaturated fatty acids are the tissue macromolecules that are most sensitive to oxidative damage. Therefore, the presence of low proportions of fatty acid unsaturation is exprected in the tissues of long‐lived animals. Accordingly, the fatty acid compositions of the major liver mitochondrial phospholipid classes from eight mammals, ranging in maximum life span potential (MLSP) from 3.5 to 46 yr, show that the total number of double bonds is inversely correlated with MLSP in both phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) (r=0.757, P<0.03, and r=0.862, P<0.006, respectively), but not in cardiolipin (P=0.323). This is due not to a low content of unsaturated fatty acids in long‐lived animals, but mainly to a redistribution between kinds of fatty acids on PtdCho and PtdEtn, shifting from arachidonic (r=0.911, P<0.002, and r=0.681, P=0.05, respectively), docosahexaenoic (r=0.931 and r=0.965, P<0.0001, respectively) and palmitic (r=0.944 and r=0.974, P<0.0001, respectively) acids to linoleic acid (r=0.942, P<0.0001, for PtdCho; and r=0.957, P<0.0001, for PtdEtn). For cardiolipin, only arachidonic acid showed a significantly inverse correlation with MLSP (r=0.904, P<0.002). This pattern strongly suggests the presence of a species‐specific desaturation pathway and deacylation‐reacylation cycle in determining the mitochondrial membrane composition, maintaining a low degree of fatty acid unsaturation in long‐lived animals.
Inhibitory effects of triterpenoids and sterols on human immunodeficiency virus‐1 reverse transcriptase
Authors: Akihisa Toshihiro , Ogihara Jun , Kato Jun , Yasukawa Ken , Ukiya Motohiko , Yamanouchi Sakae , Oishi Kunio
Published: November 2006

Fifty‐five triterpenoids consisting of 19 tetracyclic, 32 pentacyclic, and 4 incompletely cyclized triterpenoids, and 2 sterols, mostly isolated from various plant and fungal materials, were examined for their inhibitory effects on a purified human immunodeficiency virus type 1 (HIV‐1) reverse transcriptase. Twenty triterpenoids and one sterol showed inhibitory effects with 50% inhibition concentration (IC50) values less than 5.0 μM. Among these cycloartenol ferulate (IC50=2.2 μM), 24‐methylenecycloartanol ferulate (1.9 μM), lupenone (2.1 μM), betulin diacetate (1.4 μM), and karounidiol 29‐benzoate (2.2 μM) inhibited most effectively. Some of the triterpenoids and sterols may be potential new lead compounds to find still more potent HIV‐1 reverse transcriptase inhibitors.
New glycosphingolipid containing an unusual sphingoid base from the basidiomycete Polyporus ellisii
Authors: Gao Jin‐Ming , Hu Lin , Dong Ze‐Jun , Liu Ji‐Kai
Published: November 2006

A new 9‐methyl‐sphinga‐4,8‐dienine‐containing glucocerebroside (1), together with two additional known analogs, cerebrosides B and D, was isolated from the chloroform‐soluble lipid fraction of the ethanol and chloroform/methanol extract of the fruiting bodies of the basidiomycete Polyporus ellisli Berk. and characterized. The structure and relative stereochemistry of the new compound were identified as (2S,3R,4E,8E)‐1‐(β‐d‐glucopyranosyl)‐3‐hydroxy‐2‐[(R)‐2′‐hydroxyheptadecanoyl]amino‐9‐methyl‐4,8‐octadecadiene by means of spectroscopic (1H, 13C, and two‐dimensional nuclear magnetic resonance; mass spectrometry) and chemical methods.
Interaction between dietary protein and fat in triglyceride metabolism in the rat: Effects of soy protein and menhaden oil
Authors: Demonty Isabelle , Deshaies Yves , Lamarche Benoît , Jacques Hélène
Published: November 2006

The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids in the regulation of triglyceridemia in rats. Male Sprague‐Dawley rats (n=56) were subjected to 28‐d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14% w/w): (i) casein‐menhaden oil, (ii) casein‐beef tallow, (iii) soy protein‐menhaden oil, and (iv) soy protein‐beef tallow. Significant protein‐lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect on post‐heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil.
Similar effects of c9, t11‐CLA and t10,c12‐CLA on immune cell functions in mice
Authors: Kelley D. S. , Warren J. M. , Simon V. A. , Bartolini G. , Mackey B. E. , Erickson K. L.
Published: November 2006

Published results regarding the effects of CLA on immune cell functions have ranged from stimulation to inhibition. In those studies, a mixture of CLA isomers were used, and food intake was not controlled. We have examined whether the discrepancies in the results of earlier studies may be due to the lack of controlled feeding and whether the two isomers of CLA may differ in their effects on immune cell functions. Three groups of C57BL/6 female mice were fed either a control, c9,t11‐CLA‐, or t10, c12‐CLA (0.5 wt%)‐supplemented diet, 5 g/d, for 56 d. At the end of the study, the number of immune cells in spleens, bone marrows, or in circulation; proliferation of splenocytes in response to T and B cell mitogens; and prosta‐glandin secretion in vitro did not differ among the three groups. Both CLA isomers significantly‐increased in vitro tumor necrosis factor α and interleukin (IL)‐6 secretion and decreased IL‐4 secretion by splenocytes compared to those in the control group. Thus, the two CLA isomers had similar effects on all response variables tested. The discrepancies among the results from previous studies did not seem to be caused by the differences in the isomer composition of CLA used.
Evidence for multiple sterol methyl transferase pathways in Pneumocystis carinii
Authors: Zhou Wenxu , Nguyen Thi Thuy Minh , Collins Margaret S. , Cushion Melanie T. , Nes W. David
Published: November 2006

The sterol composition of Pneumocystis carinii, an opportunistic pathogen responsible for life‐threatening pneumonia in immunocompromised patients, was determined. Our purpose was to identify pathway‐specific enzymes to impair using sterol biosynthesis inhibitors. Prior to this study, cholesterol 15 (ca. 80% of total sterols), lanosterol 1, and several phytosterols common to plants (sitosterol 31, 24α‐ethyl and campesterol, 24α‐methyl 30) were demonstrated in the fungus. In this investigation, we isolated all the previous sterols and many new compounds from P. carinii by culturing the microorganism in steroid‐immunosuppressed rats. Thirty‐one sterols were identified from the fungus (total sterol=100 fg/cell), and seven sterols were identified from rat chow. Unusual sterols in the fungus not present in the diet included, 24(28)‐methylenelanosterol 2; 24(28)E‐ethylidene lanosterol 3; 24(28)Z‐ethylidene lanosterol 4; 24β‐ethyllanosta‐25(27)‐dienol 5; 24β‐ethylcholest‐7‐enol 6; 24β‐ethylcholesterol 7; 24β‐ethylcholesta‐5,25(27)‐dienol 8; 24‐methyllanosta‐7‐enol 9; 24‐methyldesmosterol 10; 24(28)‐methylenecholest‐7‐enol 11; 24β‐methylcholest‐7‐enol 12; and 24β‐methylcholesterol 13. The structural relationships of the 24‐alkyl groups in the sterol side chain were demonstrated chromatographically relative to authentic specimens, by MS and high‐resolution 1H NMR. The hypothetical order of these compounds poses multiple phytosterol pathways that diverge from a common intermediate to generate 24β‐methyl sterols: route 1, 1→2→11→12→13; route 2, 1→2→9→10→13; or 24β‐ethyl sterols: route 3, 1→2→4→6→7; route 4, 1→2→5→8→7. Formation of 3 is considered to form an interrupted sterol pathway. Taken together, operation of distinct sterol methyl transferase (SMT) pathways that generate 24β‐alkyl sterols in P. carinii with no counterpart in human biochemistry suggests a close taxonomic affinity with fungi and provides a basis for mechanism‐based inactivation of SMI enzyme to treat Pneumocystis pneumonia.
Supplementation with CLA: Isomer incorporation into serum lipids and effect on body fat of women
Authors: Petridou Anatoli , Mougios Vassilis , Sagredos Angelos
Published: November 2006

Animal studies have suggested that CLA, a natural component of meat and dairy products, may confer beneficial effects on health. However, human studies using supplementation with CLA have produced contradictory results. The aim of the present study was to further investigate the effect of CLA supplementation on human body fat, serum leptin, and serum lipids, as well as the incorporation of CLA isomers into serum lipids classes. Sixteen young healthy nonobese sedentary women received 2.1 g of CLA (divided equally between the cis,trans‐9,11 and trans,cis‐10,12 isomers) daily for 45 d and placebo for 45 d in a randomized double‐blind crossover design. Body fat was estimated (by measurement of skinfold thickness at 10 sites), and blood was sampled at the beginning, middle, and end of the entire intervention period; an additional blood sample was obtained 2 wk thereafer. No significant differences in energy, carbohydrate, lipid, or protein intake existed between the CLA and placebo intake periods. No significant differences were found in body fat or serum leptin, TAG, total cholesterol, HDL‐cholesterol, and alanine aminotransferase between CLA and placebo. The CLA isomer content of serum TAG, phospholipids, and total lipids increased 2–5 times with CLA supplementation (P<0.05). In contrast, the CLA content of cholesteryl esters did not change significantly. The period of 2 wk after the end of CLA supplementation was sufficient for its washout from serum lipids. These data indicate that supplementation with 2.1 g of CLA daily for 45 d increased its levels in blood but had no effect on body composition or the lipidemic profile of nonobese women.
A sardine oil‐rich diet increases iron absorption but does not compensate the hypoferremia associated with inflammation
Authors: Rodríguez María C. , Sáiz María P. , Mitjavila María T.
Published: November 2006

Inflammatory disorders are associated with a decrease in iron absorption because of the blockade of iron in storage organs. Fish oils, rich in n−3 PUFA, are used to prevent and treat inflammatory disorders and increase iron absorption in non‐inflamed rats. Here we examine whether n−3 PUFA prevent inflammation‐related hypoferremia. Two groups of rats were fed isoenergetic semipurified diets (a standard diet and a sardine oilrich diet). A carrageenan granuloma was induced in half of the rats of each dietary group. Ferrokinetic studies using 59Fe, hematological analyses, and iron store evaluation were performed in noninflamed and inflamed rats. Although dietary n−3 PUFA increased 59Fe absorption in carageenan‐treated rats, they did not restore the hypoferremia associated with inflammation, which is due to several mechanisms. Among these mechanisms, the blockade of iron in storage organs is relevant. However, this blockade was less evident in the spleen of inflamed rats fed the sardine oil diet.
Stability of fatty acyl‐coenzyme a thioester ligands of hepatocyte nuclear factor‐4α and peroxisome proliferator‐activated receptor‐α
Authors: Schroeder Friedhelm , Huang Huan , Hostetler Heather A. , Petrescu Anca D. , Hertz Rachel , Bar‐Tana Jacob , Kier Ann B.
Published: November 2006

Although long‐chain fatty acyl‐coenzyme A (LCFA‐CoA) thioesters are specific high‐affinity ligands for hepatocyte nuclear factor‐4α (HNF‐4α) and peroxisome proliferator‐activated receptor‐α (PPARα), X‐ray crystals of the respective purified recombinant ligand‐binding domains (LBD) do not contain LCFA‐CoA, but instead exhibit bound LCFA or have lost all ligands during the purification process, respectively. As shown herein: (i) The acyl chain composition of LCFA bound to recombinant HNF‐4α reflected that of the bacterial LCFA‐CoA pool, rather than the bacterial LCFA pool. (ii) Bacteria used to produce the respective HNF‐4α and PPARα contained nearly 100‐fold less LCFA‐CoA than LCFA. (iii) Under conditions used to crystallize LBD (at least 3 wk at room temperature in aqueous buffer), 16∶1‐CoA was very unstable in buffer alone. (iv) In the presence of the respective nuclear receptor (i.e., HNF‐4α and PPARα), LBD 70–75% of 16∶1‐CoA was degraded after 1 d at room temperature in the crystallization buffer, whereas as much as 94–97% of 16∶1‐CoA was degraded by 3 wk. (v) Cytoplasmic LCFA‐CoA binding proteins such as acyl‐CoA binding protein, sterol carrier protein‐2, and liver‐FA binding protein slowed the process of 16∶1‐CoA degradation proportional to their respective affinities for this ligand. Taken together, these data for the first time indicated that the absence of LCFA‐CoA in the crystallized HNF‐4α and PPARα was due to the paucity of LCFA‐CoA in bacteria as well as to the instability of LCFA‐CoA in aqueous buffers and the conditions used for LBD crystallization. Furthermore, instead of protecting bound LCFA‐CoA from autohydrolysis like several cytoplasmic LCFA‐CoA binding proteins, these nuclear receptors facilitated LCFA‐CoA degradation.
Maternal dietary alpine butter intake affects human milk: Fatty acids and conjugated linoleic acid isomers
Authors: Bertschi Isabelle , Collomb Marius , Rist Lukas , Eberhard Pius , Sieber Robert , Bütikofer Ulrich , Wechsler Daniel , Folkers Gerd , von Mandach Ursula
Published: November 2006

Consumption of CLA by lactating women affects the composition of their milk, but the pattern of the different CLA isomers is still unknown. We determined the effects of short maternal supplementation with CLA‐rich Alpine butter on the occurrence of FA and CLA isomers in human milk. In an open randomized controlled study with a two‐period cross‐over design, milk FA and CLA isomer concentrations were measured on postpartum days >‐20 in two parallel groups of lactating women before, during, and after consumption of defined quantities of Alpine butter or margarine with comparable fat content (10 d of butter followed by 10 d of margarine for one group, and vice versa in the other). In the 16 women who completed the study (8/group), Alpine butter supplementation, increased the C16 and C18 FA, the sum of saturated FA, the 18∶1 trans FA, and the trans FA with CLA. The CLA isomer 18∶2 c9, t11 increased by 19.7%. Significant increases were also found for the isomers t9,t111, t7,c9,t11,c13, and t8,c10 18∶2. The remaining nine of the total 14 detectable isomers showed no changes, and concentrations were <5 mg/100g fat. A breastfeeding mother can therefore modulate the FA/CLA supply of her child by consuming Alpine butter. Further studies will show whether human milk containing this FA and CLA isomer pattern acts as a functional food for newborns.
Paradoxical effect of n−3‐containing vegetable oils on long‐chain n−3 fatty acids in rat heart
Authors: Cleland Leslie G. , Gibson Robert A. , Pedler Janet , James Michael J.
Published: November 2006

Flaxseed, echium, and canola oils contain α‐linolenic acid (18∶3n−3, ALA) in a range of concentrations. To examine their effect on elevating cardiac levels of long‐chain n−3 FA, diets based on these n−3‐containing vegetable oils were fed to rats for 4 wk. Sunflower oil, which contains little ALA, was a comparator. Despite canola oil having the lowest ALA content of the three n−3‐containing vegetable oils, it was the most potent for elevating DHA (22∶6n−3) levels in rat hearts and plasma. However, the relative potencies of the dietary oils for elevation of EPA (20∶5n−3) in heart and plasma followed the same rank order as their ALA content, i.e., flaxseed>echium>canola>sunflower oil. This paradox may be explained by lower ALA intake leading to decreased competition for Δ6 desaturase activity between ALA and the 24∶5n−3 FA precursor to DHA formation.
A molecular dynamics study of an archaeal tetraether lipid membrane: Comparison with a dipalmitoylphosphatidylcholine lipid bilayer
Authors: Nicolas J. P.
Published: November 2006

Molecular dynamics simulations of an archaeal membrane made up of bipolar tetraether lipids and a dipalmitoylphosphatidylcholine (DPPC) lipid membrane were performed and compared for the first time. The simulated archaeal membrane consists of a pure monolayer of asymmetrical lipids, analogous to the main polar lipid [MPL; Swain, M., Brisson, J.‐R., Sprott, G.D., Cooper, F.P., and Patel, G.B., (1997) Identification of β‐1‐Gulose as the Sugar moiety of the Main Polar Lipid of Thermoplasma acidophilum, Biochim. Biophys. Acta 1345, 56–64] found in T. acidophilum, an extremophile archaeal organism. This simulated membrane lipid contains two cyclopentane rings located on one of the two aliphatic chains of the lipid. The archaeal membrane is simulated at 62°C, slightly above the optimal growth temperature of T. acidophilum. We compared the organization of this tetraether lipid monolayer with a DPPC bilayer simulated at 50°C, both of them being modeled in a partially hydrated state. Our results assess the singularity of the tetrather lipid organization, in particular the influence of the spanning structure on the molecular ordering within the archaeal membrane.
Dietary stearic acid and risk of cardiovascular disease: Intake, sources, digestion, and absorption
Authors: Kris‐Etherton Penny M. , Griel Amy E. , Psota Tricia L. , Gebauer Sarah K. , Zhang Jun , Etherton Terry D.
Published: November 2006

Individual FA have diverse biological effects, some of which affect the risk of cardiovascular disease (CVD). In the context of food‐based dietary guidance designed to reduce CVD risk, fat and FA recommendations focus on reducing saturated FA (SFA) and trans FA (TFA), and ensuring an adequate intake of unsaturated FA. Because stearic acid shares many physical properties with the other long‐chain SFA but has different physiological effects, it is being evaluated as a substitute for TFA in food manufacturing. For stearic acid to become the primary replacement for TFA, it is essential that its physical properties and biological effects be well understood.
Lipid characterization of seed oils from high‐palmitic, low‐palmitoleic, and very high‐stearic acid sunflower lines
Authors: Serrano‐Vega María J. , Martínez‐Force Enrique , Garcés Rafael
Published: November 2006

Information obtained in recent years regarding the enzymes involved in FA synthesis can now be applied to develop novel sunflower lines by incorporating enzymes with specific characteristics into lines with a defined background. We have generated three highly saturated mutant lines in this way and characterized their FA content. The new high‐palmitic, low‐palmitoleic lines CAS‐18 and CAS‐25, the latter on a high‐oleic background, have been selected from the high‐stearic mutant CAS‐3 by introducing a deficient stearic acid desaturase in a high‐palmitic background from the previously developed mutant lines CAS‐5 and CAS‐12, respectively. As such, the desaturation of palmitic acid and the synthesis of palmitoleic acid and its derivatives (asclepic and palmitolinoleic acids) were reduced in these high‐palmitic lines, increasing the stearic acid content. Likewise, introducing a FA thioesterase from a high‐palmitic line (e.g., CAS‐5) into the high‐stearic CAS‐3 increased the stearic acid content from 27 to 32% in the new high‐stearic line CAS‐31. As previously described in high‐palmitic lines, high growth temperatures did not reduce the linoleic acid content of the oil. Furthermore, the FA composition of TAG, DAG, and phospholipids was modified in these lines. Besides a high degree of saturation, the TAG from these new vegetable oils have a low content of saturated FA in the sn‐2 position. The α asymmetric coefficient obtained also indicates that the saturated FA are asymmetrically distributed within the TAG molecules. Indeed, the disaturated TAG content rose from 31.8 to 48.2%. These values of disaturated TAG are the highest to date in a temperate oilseed.
Influence of long‐chain polyunsaturated fatty acids on infant cognitive function
Authors: Willatts P. , Forsyth J. S. , DiModugno M. K. , Varma S. , Colvin M.
Published: November 2006

Long‐chain polyunsaturated fatty acids (LCPUFA) are important for normal visual and cortical development. In a previous study of the effects of LCPUFA on cognitive function of term infants at the age of 3 mon, we indicated that infants with evidence of reduced growth parameters at birth and impaired attention control as manifested by a late peak fixation during infant habituation assessment may benefit from LCPUFA supplementation. The aim of this prospective study was to determine whether LCPUFA supplementation and late peak fixation are related to means‐end problem‐solving ability in these same infants at the age of 9 mon. Term infants (58) were randomized to one of two formulas containing either LCPUFA or no LCPUFA and completed 4 mon of feeding with their formula. Cognitive function was assessed at 3 mon of age by measures of infant habituation. Infants (20 LCPUFA and 20 no‐LCPUFA) completed the problem‐solving assessment at 9 mon. The no‐LCPUFA group had lower scores on both measures of intention and number of solutions, but neither of these differences was significant. Analysis of covariance for the effects of group and peak fixation, covaried with gestation and birth weight, showed that the number of solutions was significantly reduced in the late peak‐fixation infants receiving no LCPUFA (P<0.02). Intention scores tended to be reduced in this group (P<0.06). The late peak‐fixation infants who received LCPUFA had solution and intention scores similar to early peak‐fixation infants receiving LCPUFA or no LCPUFA. These findings suggest that in term infants who have reduced growth parameters at birth and who show evidence of impaired attention control, information processing and problem‐solving ability in infancy may be enhanced by LCPUFA supplementation.
Tomato lycopene and low density lipoprotein oxidation: A human dietary intervention study
Authors: Agarwal Sanjiv , Rao A. Venketeshwer
Published: November 2006

Increase in low density lipoprotein (LDL) oxidation is hypothesized to be causally associated with increasing risk of atherosclerosis and coronary heart disease. In recent epidemiological studies, tissue and serum levels of lycopene, a carotenoid available from tomatoes, have been found to be inversely related to risk of coronary heart disease. A study was undertaken to investigate the effect of dietary supplementation of lycopene on LDL oxidation in 19 healthy human subjects. Dietary lycopene was provided using tomato juice, spaghetti sauce, and tomato oleoresin for a period of 1 wk each. Blood samples were collected at the end of each treatment. Serum lycopene was extracted and measured by high‐performance liquid chromatography using an absorbance detector. Serum LDL was isolated by precipitation with buffered heparin, and thiobarbituric acid‐reactive substances (TBARS) and conjugated dienes (CD) were measured to estimate LDL oxidation. Both methods, to measure LDL oxidation LDL‐TBARS and LDL‐CD, were in good agreement with each other. Dietary supplementation of lycopene significantly increased serum lycopene levels by at least twofold. Although there was no change in serum cholesterol levels (total, LDL, or high‐density lipoprotein), serum lipid peroxidation and LDL oxidation were significantly decreased. These results may have relevance for decreasing the risk for coronary heart disease.
Effects of feeding Lunaria oil rich in nervonic and erucic acids on the fatty acid compositions of sphingomyelins from erythrocytes, liver, and brain of the quaking mouse mutant
Authors: Cook Claire , Barnett Joan , Coupland Keith , Sargent John
Published: November 2006

Feeding an oil from Lunaria biennis rich in 22∶1n−9 and 24∶1n−9 to homozygous quaking (qk.qk) mice caused a large increase in the percentage of 24∶1n−9 and corresponding decreases in the percentage of 24∶0 and 22∶0 in sphingomyelins from liver, erythrocytes, and milk. Brain sphingomyelin from 2‐wk‐old qk.qk pups born to qk.qk mothers maintained on the Lunaria oil had essentially normal percentage of 24∶1n−9 and 18∶0, in contrast to pups born to mothers maintained on a control oil rich in 18∶1n−9 whose brain sphingomyelin had a markedly reduced percentage of 24∶1n−9 and an increased percentage of 18∶0. After 2 wk and up to and beyond weaning, the qk.qk pups from Lunaria‐fed mothers weaned on to the Lunaria diet had a markedly decreased percentage of 24∶1n−9 in their brain sphingomyelin, accompanied by an increased percentage of 18∶0, as compared to heterozygous quaking mice. However, the percentage of 24∶1n−9 in brain sphingomyelin in qk.qk pups weaned on to the Lunaria diet continued throughout this period (2–8 wk postbirth) to be significantly higher than in qk.qk pups weaned on to the control diet. We conclude that dietary 24∶1n−9 influences the fatty acid composition of brain sphingomyelin in qk.qk mice, but only via the mother in pre‐ or early postnatal animals. We further consider that the dietary effects may be elicited mainly in the sphingomyelin of nonmyelinated brain cells, and that the nervonic acid in myelin sphingomyelin may be formed mainly by chain elongation in oligodendrocytes from shorter chain fatty acid precursors.
Antioxidant N‐acetyl‐l‐cysteine inhibits erythropoietin‐induced differentiation of erythroid progenitors derived from mouse fetal liver
Authors: Nagata Makiko , Arimitsu Nagisa , Ito Takahiro , Sekimizu Kazuhisa
Published: November 2006

To determine the role of reactive oxygen species in erythroid differentiation, we investigated the effects of an antioxidant, N‐acetyl‐l‐cysteine (NAC), on the differentiation of erythroid progenitors derived from mouse fetal liver. In response to erythropoietin (Epo), erythroid progenitors undergo differentiation in vitro and express erythroid‐specific genes such as βmajor‐globin, Alas2, MafK, p45, Eklf, and Gata1. Expression of these genes was decreased in the presence of NAC, whereas the expression of c‐myb, which is downregulated during erythroid differentiation, remained constant. Moreover, NAC treatment inhibited an increase in the number of cells expressing high levels of erythroid‐specific antigen TER119. Treatment with another antioxidant, pyrrolidine dithiocarbamate, also caused the attenuation of TER119 expression. These results suggest that reactive oxygen species are involved in Epo‐mediated erythroid differentiation.
Impact of chronic pain on everyday physical activity⋆
Authors: van den Berg‐Emons Rita J. , Schasfoort Fabiënne C. , de Vos Leonard A. , Bussmann Johannes B. , Stam Henk J.
Published: November 2006

Although patients with chronic pain are often considered to have reduced levels of everyday physical activity, data on their activity levels are scarce and inconclusive. Therefore, this study explored whether patients with chronic pain have reduced activity levels, as objectively measured with an activity monitor. The activity monitor is based on long‐term ambulatory monitoring of signals from body‐fixed accelerometers during everyday life, aimed at assessment of mobility‐related activities. Measurements with the monitor were performed during a weekday (24h) in 18 patients with chronic pain and compared with measurements obtained from 18 gender and age matched healthy comparison subjects.

The mean (SD) age of the patients was 44 (11) years, and the mean (SD) duration of their complaints was 8 (7) years. Compared with the healthy subjects, the duration of dynamic activities was not significantly reduced (p=0.10) in the patient group. Mean (SD) intensity of everyday physical activity was lower (p=0.03) in the patients than in the healthy comparison subjects (0.021 [0.006] g versus 0.026 [0.004] g), and patients spent more time lying down (47.0 [10.2]% versus 34.3 [5.6] %; p=0.000) and less time sitting (29.2 [8.9]% versus 36.4 [9.3]%; p=0.03) than the healthy comparison subjects.

In spite of significant differences between patients and healthy comparison subjects for some aspects of the activity pattern (which may reflect pain behaviour), the impact of chronic pain on everyday physical activity was relatively small.
Methylation of Smad6 by protein arginine N‐methyltransferase 1
Authors: Inamitsu Masako , Itoh Susumu , Hellman Ulf , ten Dijke Peter , Kato Mitsuyasu
Published: November 2006

Signal transduction pathways utilize posttranslational modifications to regulate the activity of their components in a temporal‐spatial and efficient fashion. Arginine methylation is one of the posttranslational modifications that can result in monomethylated‐, asymmetric dimethylated‐ and/or symmetric dimethylated‐arginine residues in proteins. Here we demonstrate that inhibitory‐Smads (Smad6 and Smad7), but not receptor‐regulated‐ (R‐)Smads and the common‐partner Smad4, can be methylated by protein arginine N‐methyltransferase (PRMT)1. Using mass‐spectrometric analysis, we found that PRMT1 dimethylates arginine74 (Arg74) in mouse Smad6. PRMT1 interacts with the N‐terminal domain of Smad6 in which Arg74 residue is located. Assays examined so far have shown no significant differences between the functions of Smad6 and those of methylation‐defective Smad6 (Smad6R74A). Both wild‐type and Smad6R74A were equally efficient in blocking BMP‐induced growth arrest upon their ectopic expression in HS‐72 mouse B‐cell hybridoma cells.
Protective effect of acetyl‐l‐carnitine against oxidative stress induced by antiretroviral drugs
Authors: Ferraresi Roberta , Troiano Leonarda , Roat Erika , Nemes Elisa , Lugli Enrico , Nasi Milena , Pinti Marcello , Calvani Menotti , Iannuccelli Maurizio , Cossarizza Andrea
Published: November 2006

Both HIV infection per se and antiretroviral drugs might contribute to oxidative stress and mitochondrial dysfunctions. In this study we assess zidovudine, stavudine and didanosine on U937 and CEM cell lines. All these drugs induced apoptosis and increased intracellular hydrogen peroxide but not superoxide anions. The addition of acetyl‐l‐carnitine (ALC) was able to prevent the pro‐oxidant effect of the drugs tested. Supplementation with ALC, deficient in certain cohorts of HIV‐infected individuals, especially on high active antiretroviral therapy regimen, has been associated with favourable effects. These data suggest that one of these effects could be a direct anti‐oxidant action.
DETERMINANTS OF ADOLESCENT PREGNANCY IN AN URBAN AREA IN TURKEY: A POPULATION-BASED CASE-CONTROL STUDY
Authors: GÖKÇE BIRSEN , ÖZŞAHIN AYSUN , ZENCIR MEHMET
Published: November 2006

The aim of this study was to determine the degree to which socioeconomic status is a risk factor for first birth at age 19 or younger in married women in an urban area of Turkey. The research was a population-based case-control study. The study group comprised all married and pregnant women aged 15–19 (adolescent pregnancies) attending primary care centres (144 subjects). Married women between 20 and 29 years of age, experiencing their first pregnancy (adult pregnancies), were determined as the control group (144 subjects). A questionnaire was completed for each subject during face-to-face interviews. Adolescent pregnancy was more frequent in women from families with a low socioeconomic status, as determined by occupation (class) and income; both were associated with adolescent pregnancy. Multiple logistic regression analysis identified seven factors associated with adolescent pregnancy: exposure to violence within the family prior to marriage; families partially opposed or unopposed to adolescent marriage; secondary school or lower education level; lack of social security; living in houses in which the number of persons per room was over 1; unemployed women; and having sisters with a history of adolescent pregnancy.
Fabrication of Artificial Endothelialized Tubes with Predetermined Three‐Dimensional Configuration from Flexible Cell‐Enclosing Alginate Fibers
Authors: Takei Takayuki , Sakai Shinji , Yokonuma Toru , Ijima Hiroyuki , Kawakami Koei
Published: November 2006

One possible strategy for creating three‐dimensional (3D) tissue‐engineered organs in vitro is to develop a vasculature for sufficient transport of oxygen and nutrients within these constructs. Here, we describe a novel technique to fabricate endothelialized tubes with predetermined 3D configuration, as a starting point for self‐developing capillary‐like networks in vitro. Calcium‐alginate hydrogel fibers of ca. 250 and 500 μm in diameter, enclosing bovine carotid artery vascular endothelial cells (BECs), were used as templates for endothelialized tubes. Fibers were prepared by extruding a 2% (w/v) sodium alginate solution containing BECs into a 100 mM calcium chloride solution flowing in the same direction. Fibers were embedded in type I collagen gels and enzymatically degraded by alginate lyase, resulting in channels with predetermined 3D configuration filled with a BEC suspension. Cells attached to and covered the surfaces of the channels. Exposing the cells to medium containing basic fibroblast growth factor resulted in their migration into the ambient collagen gel and self‐assembly into capillary‐like structures. These results demonstrate that using artificial endothelialized tubes with predetermined 3D configuration, as a starting point for a self‐developing capillary‐like network, could be potentially useful for constructing 3D tissue‐engineered organs.
Is C-reactive protein a better predictor of recurrent carotid disease following carotid endarterectomy than established risk factors for atherosclerosis?
Authors: Lušic  , Radonic  , Pavelin  , Bilic
Published: November 2006

Background: The study was undertaken to identify possible relations between established and novel risk factors for atherosclerosis (gender, age, diabetes mellitus, hypertension, smoking and C-reactive protein) and the possibility of carotid restenosis following carotid endarterectomy (CEA). Patients and methods: A prospective study of 193 consecutive patients, admitted electively for carotid endarterectomy during 68 months, was conducted. 131 patients had symptomatic and 62 asymptomatic carotid disease. An attempt was made to follow-up on all operated arteries with duplex sonography at 2 months, 6 months, 12 months, and 24 months postoperatively. The correlation of previously mentioned variables (gender, age, diabetes mellitus, hypertension, smoking and average values of C-reactive protein) with progressive or recurrent disease was determined by chi-square analysis and analysis of variance. Results: Of all 193 examined patients 29 demonstrated increasing degree of artery stenosis, while recurrent artery stenosis of > 69% was diagnosed in 11 patients. Age, gender, hypertension, and diabetes did not play a significant role in the presence of progressive (or recurrent) disease, while active smokers and patients with preoperative and average C-reactive protein (CRP) levels over 3.0 mg/L had a greater propensity to develop progression (or recurrence) of carotid disease. Conclusions: Increased levels of CRP in serum may be a better predictor of carotid restenosis after CEA than other established risk factors for vascular disease – except active smoking.
Density depletion and Hall effect in magnetic reconnection
Authors: Yang H. A. , Jin S. P. , Zhou G. C.
Published: November 2006

Density depletions were detected by Wind, Cluster, and Polar spacecrafts in the observations of diffusion region encounters at the Earth's magnetotail and magnetopause. In this report we investigate the layers of density depletion in magnetic reconnection using a 2.5‐dimensional Hall MHD code developed from a multistep implicit scheme. The numerical results at the quasi‐steady state of the Hall MHD reconnection with di/Lc ≥ 1.0, where di is the ion inertial length and Lc is the half thickness of the initial current sheet, show not only the density depletions along the magnetic separatrices but also a density dip in the x direction near the X neutral line. The comparative tests with various Hall terms demonstrate that the density depletion in the magnetic reconnection is a peculiar feature of the case with a strong Hall effect (di/Lc ≥ 1.0). The layers of low density following the shape of separatrices are in coincidence with the regions of high magnetic pressure. In the spatial profile of density ρ along z, which is in quantitative agreement with Cluster observation, the obvious dips located at the separatrices coincide with the peak and valley in the profile of (J × B)z for the case with di/Lc = 2.0. It indicates the major role of the Hall term in the formation of the density depletion layers near the separatrices. On the basis of the comparison between Wind observation and simulation results, we argue that the density dip observed by Wind would be distributed around the reconnection X‐line, rather than along the magnetic separatrix. In the case with a strong Hall effect, the in‐plane ion flows go around the diffusion region, and enterable ions in this region are significantly reduced due to the action of the in‐plane Lorentz force. A density dip in the vicinity of the X‐line is attributed to the hard entry of in‐plane ion flow and might be related to an increase of the ion drift velocity in the y direction.
Nutrient spiraling in streams and river networks
Authors: Ensign Scott H. , Doyle Martin W.
Published: November 2006

Over the past 3 decades, nutrient spiraling has become a unifying paradigm for stream biogeochemical research. This paper presents (1) a quantitative synthesis of the nutrient spiraling literature and (2) application of these data to elucidate trends in nutrient spiraling within stream networks. Results are based on 404 individual experiments on ammonium (NH4), nitrate (NO3), and phosphate (PO4) from 52 published studies. Sixty‐nine percent of the experiments were performed in first‐ and second‐order streams, and 31% were performed in third‐ to fifth‐order streams. Uptake lengths, Sw, of NH4 (median = 86 m) and PO4 (median = 96 m) were significantly different (α = 0.05) than NO3 (median = 236 m). Areal uptake rates of NH4 (median = 28 μg m−2 min−1) were significantly different than NO3 and PO4 (median = 15 and 14 μg m−2 min−1, respectively). There were significant differences among NH4, NO3, and PO4 uptake velocity (median = 5, 1, and 2 mm min−1, respectively). Correlation analysis results were equivocal on the effect of transient storage on nutrient spiraling. Application of these data to a stream network model showed that recycling (defined here as stream length ÷ Sw) of NH4 and NO3 generally increased with stream order, while PO4 recycling remained constant along a first‐ to fifth‐order stream gradient. Within this hypothetical stream network, cumulative NH4 uptake decreased slightly with stream order, while cumulative NO3 and PO4 uptake increased with stream order. These data suggest the importance of larger rivers to nutrient spiraling and the need to consider how stream networks affect nutrient flux between terrestrial and marine ecosystems.
Bathymetry‐topography effects on saltwater–fresh groundwater interactions around the shrinking Aral Sea
Authors: Shibuo Yoshihiro , Jarsjö Jerker , Destouni Georgia
Published: November 2006

Large‐scale irrigational schemes have drastically reduced the surface water discharge into the Aral Sea, causing a sea surface level lowering of more than 20 m since 1960 and severe water quality deterioration in the region. We investigate the dynamics of submarine groundwater discharge (SGD) into the Aral Sea as well as the saltwater intrusion (SWI) into the coastal groundwater around the Aral Sea during its shrinkage by using the U.S. Geological Survey SUTRA code. Results show that the regional topography and bathymetry largely influence SGD and SWI transients as the Aral Sea shrinks. Considering the flat conditions that prevail in the southeastern Aral Sea and the irrigated Amu Darya delta, SGD drops as the sea starts to shrink because the shoreline displacement prevents seawater inflow to the aquifer and subsequent return flow to the sea. In this flat bathymetry case the groundwater discharging into the Aral Sea becomes as saline as the seawater because saltwater remains below the dried seabed. In contrast, for the steep bathymetry of the essentially uninhabited northwestern region the SGD increases as a combined effect of sea surface lowering, density differences, and storage, with the SGD salinity remaining below seawater salinity and reflecting a considerable freshwater component. Considering the potential for groundwater pumping in the original coastline vicinity for freshwater supply use, our results indicate a decreased risk of SWI in the northwestern Aral Sea region under the post‐1960 sea level lowering conditions.
High loadings and source strengths of organic aerosols in China
Authors: Wang Gehui , Kawamura Kimitaka , Watanabe Tomomi , Lee Shuncheng , Ho Kinfai , Cao Junji
Published: November 2006

Nation‐wide studies of organic aerosols were conducted on a molecular level in 15 Chinese cities. The results showed strikingly high levels of organic compounds (e.g., annual concentrations of polycyclic aromatic hydrocarbons, phthalates, sugars and diacids are 110, 370, 400 and 830 ng m−3, respectively), especially in the mid‐west region during winter (up to 125 μg m−3 organic carbon). Fossil fuel combustion and/or biomass burning products are 3−30 times more abundant in winter than in summer. In contrast, significant quantity of phthalates (168−2200 ng m−3) was detected in summer. Concentrations of the pollutants are generally 1−3 orders of magnitude higher than those in developed countries. Their source strengths are characterized in winter by fossil fuel combustion, followed by secondary oxidation, plant wax emissions and biomass burning, whereas in summer by secondary oxidation, followed by fossil fuel combustion and plastic emissions.
Ion composition and pressure changes in storm time and nonstorm substorms in the vicinity of the near‐Earth neutral line
Authors: Kistler L. M. , Mouikis C. G. , Cao X. , Frey H. , Klecker B. , Dandouras I. , Korth A. , Marcucci M. F. , Lundin R. , McCarthy M. , Friedel R. , Lucek E.
Published: November 2006

Using CLUSTER/CODIF data from close to ∼19 Re in the magnetotail, we have performed a superposed epoch analysis of storm time and nonstorm substorms to determine how the ion composition changes during a substorm. We find that the median O+ density and pressure in the plasma sheet are a factor of 5 higher during storm times than during nonstorm times. However, we do not observe significant changes in the composition during a substorm that would indicate that ionospheric outflow is playing a dynamic role in loading the plasma sheet or triggering the substorm at this location. There are differences between the storm time and nonstorm substorms, and it is intriguing to consider whether the composition differences play a role. The storm time substorms exhibit more loading and faster unloading than the nonstorm substorms. In addition, we observe differences in the H+ and O+ behavior at onset in the storm time substorms that we attribute to the different dynamics of the two ion species at the reconnection site and during the field reconfiguration due to their different gyroradii. The H+ density and pressure decrease over the whole energy range at substorm onset, while the O+ density and pressure decrease less, and the O+ temperature increases. That more O+ is left after substorm onset indicates that either the O+ is more quickly replenished from O+ in the lobes and/or that the more energetic O+, due to its larger gyroradius, is not depleted when the field reconfigures and is accelerated in the thin current sheet.
Archaeal tetraether membrane lipid fluxes in the northeastern Pacific and the Arabian Sea: Implications for TEX86 paleothermometry
Authors: Wuchter Cornelia , Schouten Stefan , Wakeham Stuart G. , Sinninghe Damsté Jaap S.
Published: November 2006

The newly introduced temperature proxy, the tetraether index of archaeal lipids with 86 carbon atoms (TEX86), is based on the number of cyclopentane moieties in the glycerol dialkyl glycerol tetraether (GDGT) lipids of marine Crenarchaeota. The composition of sedimentary GDGTs used for TEX86 paleothermometry is thought to reflect sea surface temperature (SST). However, marine Crenarchaeota occur ubiquitously in the world oceans over the entire depth range and not just in surface waters. We analyzed the GDGT distribution in settling particulate organic matter collected in sediment traps from the northeastern Pacific Ocean and the Arabian Sea to investigate the seasonal and spatial distribution of the fluxes of crenarchaeotal GDGTs and the origin of the TEX86 signal transported to the sediment. In both settings the TEX86 measured at all trap deployment depths reflects SST. In the Arabian Sea, analysis of an annual time series showed that the SST estimate based on TEX86 in the shallowest trap at 500 m followed the in situ SST with a 1 to 3 week time delay, likely caused by the relatively low settling speed of sinking particles. This revealed that the GDGT signal that reaches deeper water is derived from the upper water column rather than in situ production of GDGTs. The GDGT temperature signal in deeper traps at 1500 m and 3000 m did not show a seasonal cyclicity observed in the 500 m trap but rather reflected the annual mean SST. This is probably due to a homogenization of the TEX86 SST signal carried by particles as they ultimately reach the interior of the ocean. Our data confirm the use of TEX86 as a temperature proxy of surface ocean waters.