bluuebunny/crossref_metadata_2025 huggingface dataset:
The Complexity and Challenges of Genetic Counseling and Testing for Inflammatory Bowel Disease
Authors: Cummings Shelly A. , Rubin David T.
Published: November 2006

Inflammatory bowel disease (IBD) is an umbrella term referring to two chronic idiopathic intestinal diseases: ulcerative colitis (UC) and Crohn's disease (CD). Both UC and CD are characterized by immune activation that leads to symptoms, but the location, severity and behavior of the inflammation varies among individuals and in characteristic ways between UC and CD. A majority of patients with IBD are diagnosed in young adulthood, but the response to therapy is variable and difficult to predict, with some patients demonstrating a prompt and effective remission while others have continuous symptoms that do not respond to existing medical options. Surgery remains a frequent and necessary occurrence among patients with IBD, but in UC it is considered curative, while in CD only temporizing. Clinical observations, epidemiological studies, and molecular genetics have provided strong evidence that both genetic and environmental factors are important determinants for disease susceptibility. In recent years, a number of genes have been identified that associate with CD and UC, although the clinical utility of these discoveries in patients or in susceptible family members has not been determined. Nonetheless, it is hoped that these fundamental advances in our understanding of IBD will lead to better therapies for patients and prevention strategies for those who are susceptible. Effective incorporation of clinical genetic testing for IBD into practice will require appropriate education and counseling.
Regiospecific enzymatic oxygenation of cis‐vaccenic acid during aerobic senescence of the halophilic purple sulfur bacterium Thiohalocapsa halophila
Authors: Marchand Daphné , Grossi Vincent , Hirschler‐Rea Agnès , Rontani Jean‐François
Published: November 2006

A regiospecific oxygenation of the allylic carbon 10 of cis‐vaccenic acid has been observed in senescent cells of the halophilic purple sulfur bacterium Thiohalocapsa halophila incubated under aerobic conditions in darkness. The results obtained strongly suggest that these enzymatic processes involve the initial dioxygenase‐mediated formation of 10‐hydroperoxyoctadec‐cis‐11‐enoic acid, which is not accumulated in the cells of T. halophila owing to its high cytotoxic properties. Deuterium labeling and GC‐MS analyses enabled us to demonstrate that subsequent enzymatic conversions of this allylic hydroperoxide involved reduction, cleavage, isomerization, and saturation reactions. Some of the specific oxidation products thus formed could constitute potential T. halophila biomarkers.
Two novel glucosylceramides from gonads and body walls of the patagonian starfish Allostichaster inaequalis
Authors: Díaz de Vivar María E. , Seldes Alicia M. , Maier Marta S.
Published: November 2006

From the water‐insoluble lipid fraction of the chloroform/methanol/water extract of the gonads and body walls of the Patagonian starfish Allostichaster inaequalis, two new glucosylceramides (4 and 7) were isolated together with the known phalluside‐1 (1) and two glucosylceramides (2 and 3) previously isolated from the starfish Cosmasterias lurida. The new compounds were characterized as (2S,3R,4E,8E,10E)‐1‐(β‐d‐glucopyranosyloxy)‐3‐hydroxy‐2‐[(R)‐2‐hydroxy‐15‐tetracosenoyl] amino‐4,8,10‐octadecatriene (4) and (2S,3R,4E,15Z)‐1‐(β‐d‐glucopyranosyloxy)‐3‐hydroxy‐2‐[(R)‐2‐hydroxyhexadecanoyl] amino‐4,15‐docosadiene (7) by means of spectroscopic and chemical methods.
Analysis of diastereomeric DAG naphthylethylurethanes by normal‐phase HPLC with on‐line electrospray MS
Authors: Ågren J. J. , Kuksis A.
Published: November 2006

Normal‐phase HPLC resolution of sn‐1,2(2,3)‐ and x‐1,3‐DAG generated by partial Grignard degradation from natural TAG was carried out with both (R)‐(−) and (S)‐(+)‐1‐(1‐naphthyl)ethylurethane derivatives. The diastereomeric sn‐1,2‐ and sn‐2,3‐DAG derivatives were resolved using two Supelcosil LC‐Si (5 μm, 25 cm × 4.6 mm i.d.) columns in series and an isocratic elution with 0.37% isopropanol in hexane at a flow rate of 0.7 mL/min. The DAG were detected by UV absorption at 280 nm and were identified by electrospray ionization MS in the positive ion mode following postcolumn addition of chloroform/methanol/30% ammonium hydroxide (75∶24.5∶0.5, by vol) at 0.6 mL/min. Application of the method to a stereospecific analysis of the molecular species of TAG of rat VLDL showed that the TAG composition of VLDL circulating under basal conditions differs markedly from that of VLDL secreted by the liver during inhibition of serum lipases. The inhibition of serum lipases resulted in a significant proportional decrease in 16∶0 and PUFA and an increase in 18∶0 and oligoenoic FA in the sn‐1‐position, whereas the FA compositions in the sn‐2‐ and sn‐3‐positions were much less affected.
Identification and expression of mammalian long‐chain PUFA elongation enzymes
Authors: Leonard Amanda E. , Kelder Bruce , Bobik Emil G. , Chuang Lu‐Te , Lewis Christopher J. , Kopchick John J. , Mukerji Pradip , Huang Yung‐Sheng
Published: November 2006

In mammalian cells, Sprecher has proposed that the synthesis of long‐chain PUFA from the 20‐carbon substrates involves two consecutive elongation steps, a Δ6‐desaturation step followed by retroconversion (Sprecher, H., Biochim. Biophys. Acta 1486, 219–231, 2000). We searched the database using the translated sequence of human elongase ELOVL5, whose encoded enzyme elongates monounsaturated and polyunsaturated FA, as a query to identify the enzyme(s) involved in elongation of very long chain PUFA. The database search led to the isolation of two cDNA clones from human and mouse. These clones displayed deduced amino acid sequences that had 56.4 and 58% identity, respectively, to that of ELOVL5. The open reading frame of the human clone (ELOVL2) encodes a 296‐amino acid peptide, whereas the mouse clone (Elovl2) encodes a 292‐amino acid peptide. Expression of these open reading frames in baker's yeast, Saccharomyces cerevisiae, demonstrated that the encoded proteins were involved in the elongation of both 20‐and 22‐carbon long‐chain PUFA, as determined by the conversion of 20∶4n−6 to 22∶4n−6, 22∶4n−6 to 24∶4n−6, 20∶5n−3 to 22∶5n−3, and 22∶5n−3 to 24∶5n−3. The elongation activity of the mouse Elovl2 was further demonstrated in the transformed mouse L cells incubated with long‐chain (C20‐and C22‐carbon) n−6 and n−3 PUFA substrates by the significant increase in the levels of 24∶4n−6 and 24∶5n−3, respectively. This report demonstrates the isolation and identification of two mammalian genes that encode very long chain PUFA specific elongation enzymes in the Sprecher pathway for DHA synthesis.
Effect of dietary conjugated linoleic acid (CLA) on metabolism of isotope‐labeled oleic, linoleic, and CLA isomers in women
Authors: Emken E. A. , Adlof R. O. , Duval S. , Nelson G. , Benito P.
Published: November 2006

The purpose of this study was to investigate the effect of dietary CLA on accretion of 9c‐18∶1, 9c, 12c‐18∶2, 10t, 12c‐18∶2, and 9c, 11t‐18∶2 and conversion of these FA to their desaturated, elongated, and chain‐shortened metabolites. The subjects were six healthy adult women who had consumed normal diets supplemented with 6 g/d of sunflower oil or 3.9 g/d of CLA for 63 d. A mixture of 10t, 12c‐18∶2‐d4, 9c, 11t‐18∶2‐d6, 9c‐18∶1‐d8, and 9c, 12c‐18∶2‐d2, as their ethyl esters, was fed to each subject, and nine blood samples were drawn over a 48‐h period. The results show that dietary CLA supplementation had no effect on the metabolism of the deuterium‐labeled FA. These metabolic results were consistent with the general lack of a CLA diet effect on a variety of physiological responses previously reported for these women. The 2H‐CLA isomers were metabolically different. The relative percent differences between the accumulation of 9c, 11t‐18∶2‐d6 and 10t, 12c‐18∶2‐d4 in plasma lipid classes ranged from 9 to 73%. The largest differences were a fourfold higher incorporation of 10t, 12c‐18∶2‐d4 than 9c, 11t‐18∶2‐d6 in 1‐acyl PC and a two‐ to threefold higher incorporation of 9c, 11t‐18∶2‐d6 than 10t, 12c‐18∶2‐d4 in cholesterol esters. Compared to 9c‐18∶1‐d8 and 9c, 12c‐18∶2‐d2, the 10t, 12c‐18∶2‐d4 and 9c, 11t‐18∶2‐d6 isomers were 20–25% less well absorbed. Relative to 9c‐18∶1, incorporation of the CLA isomers into 2‐acyl PC and cholesterol ester was 39–84% lower and incorporation of 10t, 12c‐18∶2 was 50% higher in 1‐acyl PC. This pattern of selective incorporation and discrimination is similar to the pattern generally observed for trans and cis 18∶1 positional isomers. Elongated and desaturated CLA metabolites were detected. The concentration of 6c, 10t, 12c‐18∶3‐d4 in plasma TG was equal to 6.8% of the 10t, 12c‐18∶2‐d4 present, and TG was the only lipid fraction that contained a CLA metabolite present at concentrations sufficient for reliable quantification. In conclusion, no effect of dietary CLA was observed, absorption of CLA was less than that of 9c‐18∶1, CLA positional isomers were metabolically different, and conversion of CLA isomers to desaturated and elongated metabolites was low.
Retinal sensitivity loss in third‐generation n‐3 PUFA‐deficient rats
Authors: Weisinger Harrison S. , Armitage James A. , Jeffrey Brett G. , Mitchell Drake C. , Moriguchi Toru , Sinclair Andrew J. , Weisinger Richard S. , Salem Norman
Published: November 2006

A previous study conducted in guinea pigs suggested that ingestion of diets high in EPA and DHA may result in suboptimal retinal function. The aim of the present study was to evaluate retinal function in pigmented (Long‐Evans) rats, raised to a third generation on diets that were either deficient in n‐3 PUFA or adequate (with the addition of DHA). Electroretinographic assessment employed full‐field white flash stimulation. Photoreceptor responses were evaluated in terms of peak amplitudes and implicit times (a‐wave, b‐wave), intensity‐response functions (Naka‐Rushton), and the parameters of a model of transduction (P3). Retinal phospholipid FA composition was measured by capillary GLC. DHA levels were reduced by 55% in n‐3‐deficient animals compared with the n‐3‐adequate group, whereas the levels of docosapentaenoic acid n‐6 were 44 times higher in n‐3‐deficient animals. The level of arachidonic acid was marginally higher (12.8%) in n‐6‐adequate animals. The n‐3‐deficient animals exhibited significantly reduced retinal sensitivity (σ and S values were both affected by 0.29 log units) and increased b‐wave implicit times compared with those fed the n‐3‐adequate diet. These data suggest that n‐3 PUFA are required for development of retinal sensitivity, more so than other indices of retinal function assessed by current methods, such as maximal response amplitude. However, the benefit for retinal function of adding preformed DHA to diets already replete in n‐3 PUFA remains unclear.
n‐3 FA increase liver uptake of HDL‐cholesterol in mice
Authors: Morvan Valérie le , Dumon Marie‐France , Palos‐Pinto Antonio , Bérard Annie M.
Published: November 2006

In humans, diets rich in fish oil (containing n‐3 FA) decrease the incidence of coronary artery diseases. This is thought to be caused by the induction in liver and skeletal muscle of genes involved in lipid oxidation, and to the repression in liver and adipose tissue of genes responsible for lipogenesis. n‐3 FA are known to reduce the synthesis of FA and TG in the liver, resulting in a decrease of plasma concentrations of TG‐rich lipoproteins. On the other hand, little is known of a possible effect of n‐3 FA on HDL metabolism. To investigate this question, female C57BI/6J mice were fed an n‐3 FA‐enriched diet for 16 wk. As expected from previous studies, we found that total cholesterol, TG, and phospholipids were reduced in the plasma of treated mice. We also found that HDL‐cholesterol decreased after this treated and that the in vivo fractional catabolic rate of HDL‐cholesteryl ester was significantly higher in treated mice than in control mice fed a standard diet. Consistent with these results, treated mice exhibited increased uptake of HDL‐cholesteryl ester in the liver. Moreover, quantitative reverse transcriptase‐PCR analysis showed a two‐to threefold increase in scavenger receptor B‐1 gene expression. Taken together, these results suggest that an n‐3 FA‐enriched diet stimulates one step in the reverse cholesterol transport in mice, probably by increasing the amount of the scavenger receptor class B‐1. These effects of n‐3 FA on HDL metabolism may contribute to their beneficial effects on the vasculature.
Eicosapentaenoic acid promotes apoptosis in Ramos cells via activation of caspase‐3 and ‐9
Authors: Heimli Hilde , Giske Camilla , Naderi Soheil , Drevon Christian A. , Hollung Kristin
Published: November 2006

Eicosapentaenoic acid (EPA; 20∶5n−3) may reduce the cell number in cultured leukemia/lymphoma cells owing to reduced cell proliferation, induction of cell death, or a combination of these processes. EPA has been shown to promote apoptosis in Ramos cells, and our present study was focused on a possible cell cycle arrest and the pathways by which the apoptotic process is induced. Apoptosis may proceed along the intrinsic (mitochondrial) or the extrinsic (death receptor) pathway, which are mediated via different caspases. Caspases are a class of homologous cysteine proteases recognized as pivotal mediators of apoptosis. We investigated whether EPA affects progression of the cell cycle or promotes apoptosis directly. By incorporation of [3H]thymidine and [3H]valine, we showed that DNA, as well as protein synthesis, was reduced after incubation of Ramos cells with EPA for 6h. We monitored cell cycle distribution by 5‐bromo‐2′‐deoxyuridine staining and observed no cell cycle arrest in the EPA‐incubated cells. Incubation of cells with EPA caused PS‐flipping, as demonstrated by annexin V‐binding (flow cytometry), and cleavage of poly(ADP‐ribose) polymerase measured by Western blot analysis. Furthermore, we observed increased activity of caspase‐3 and‐9, but not of caspase‐8. Whereas inhibitors of caspase‐3 and‐9 reduced EPA‐induced apoptosis, inhibition of caspase‐8 did not. This suggests that EPA may promote apoptosis via the intrinsic pathway in Ramos cells. Thus, the reduction in cell number can be explained by a direct apoptotic effect of EPA rather than via cell cycle arrest.
Characterization of trans‐monounsaturated alkenyl chains in total plasmalogens (1‐O‐alk‐1′‐enyl‐2‐acyl glycerophospholipids) from sheep heart
Authors: Wolff Robert L.
Published: November 2006

In the present study, we investigated the alkenyl chains from sheep heart plasmalogens (1‐O‐alk‐1′‐enyl‐2‐acyl glycerophospholipids) after their conversion into trimethylene dioxyalkanyl (TMDOA) derivatives. Particular attention was given to monounsaturated alkenyl chains (C18 mainly). For this purpose, a combination of silver ion TLC and GLC on highly polar, very long capillary columns was applied to TMDOA derivatives. Approximately 30 different alkenyl chains could be separated, and the main observation was that the component previously reported as a cis‐9 18∶1 alkenyl chain in plasmalogens embraces in fact a wide range of trans and cis isomers, in amounts equal to 7.9 and 5.6%, respectively, of total alkenyl chains. Concerning the trans‐monoenoate fraction, isomers with their ethylenic bond spanning from Δ6–Δ8 to Δ16 were tentatively identified on the basis of their distribution profile, which was similar to that of trans‐18∶1 acids prepared and isolated from sheep adipose tissue. The main trans‐monoenoic C18 alkenyl chain in sheep heart plasmalogens would thus have its double bond in position 11, which seems logical, as alkenyl chains are derived from the corresponding alcohols, themselves issued from the corresponding FA, and in this particular case, vaccenic (trans‐11 18∶1) acid. cis‐Monoenoic C18 alkenyl chains also appear more complex than realized earlier, showing in particular isomers with their ethylenic bond farther than the Δ9 position, in addition to the main isomer derived from oleic acid. Several trans‐16∶1 alkenyl chains could be observed (totaling ca. 1%), but cis‐16∶1 isomers were present in trace amounts only.
A direct method for regiospecific analysis of TAG using α‐MAG
Authors: Turon F. , Bachain P. , Caro Y. , Pina M. , Graille J.
Published: November 2006

An analytical procedure was developed for regiodistribution analysis of TAG using α‐MAG prepared by an ethyl magnesium bromide deacylation. In the present communication, the deacylation procedure is shown to lead to representative α‐MAG, allowing the composition of the native TAG in the α‐position to be determined directly. The composition in the β‐position can then be estimated from the composition of the α‐MAG and TAG according to the formula, 3×TAG‐2×α‐MAG. The estimates are superior to those obtained using the α,β‐DAG and Brockerhoff calculations as they come closer to the theoretical value and have smaller SD. The present procedure, first demonstrated on a synthetic TAG, was then successfully applied to the analysis of borage oil, milkfat, and tuna oil.
Visual acuity and retinal function in infant monkeys fed long‐chain PUFA
Authors: Jeffrey Brett G. , Mitchell Drake C. , Hibbeln Joseph R. , Gibson Robert A. , Lee Chedester A. , Salem Norman
Published: November 2006

Previous randomized clinical trials suggest that supplementation of the human infant diet with up to 0.35% DHA may benefit visual development. The aim of the current study was to assess the impact of including arachidonic acid (AA) and a higher level of DHA in the postnatal monkey diet on visual development. Infant rhesus monkeys were fed either a control diet (2.0% α‐linolenic acid as the sole n−3 FA) or a supplemented diet (1.0% DHA and 1.0% AA) from birth. Visual evoked potential acuity was measured at 3 mon of age. Rod and cone function were assessed in terms of parameters describing phototransduction. Electroretinogram (ERG) amplitudes and implicit times were recorded over a wide intensity range (−2.2 to 4.0 log scot td‐sec) and assessed in terms of intensity response functions. Plasma DHA and AA were significantly increased (P <0.001) in the diet‐supplemented monkeys compared with the control monkeys. There was an approximately equal effect of diet for the rod phototransduction parameters, sensitivity, and capacitance but in the opposite directions. Diet‐supplemented monkeys had significantly shorter b‐wave implicit times at low retinal illuminances (<−0.6 log scot td‐sec). There were no significant effects of diet for visual acuity or the other 23 ERG parameters measured. The results suggest that supplementation of the infant monkey diet with 1.0% DHA and 1.0% AA neither harms nor provides substantial benefit to the development of visual acuity or retinal function in the first four postnatal months.
Relationship between platelet phospholipid FA and mean platelet volume in healthy men
Authors: Li Duo , Turner Alan , Sinclair Andrew J.
Published: November 2006

Increased mean platelet volume (MPV) has been suggested as an independent risk factor for acute myocardial infarction and the increased reactivity of large platelets. The aim of this study was to investigate the correlation between platelet phospholipid (PL) PUFA composition and MPV in 139 free‐living healthy men ages 20–55 yr (vegans, n=18; ovolacto vegetarians, n=43; modrerate meat‐eaters, n=60; and high meateaters, n=18). Each subject completed a semiquantitative Food Frequency Questionnaire and gave a blood sample. Platelet PL FA composition and MPV were determined by standard methods. MPV was significantly greater in the vegans than in the ovolacto vegetarian, moderate, or high meat‐eater groups (P<0.01). Both vegan and ovolacto vegetarian groups had significantly higher platelet PL 18∶2n−6 and 22∶4n−6, and lower 20∶5n−3 and 22∶6n−3 compared with the moderate and high meat‐eater groups. The vegans demonstrated a significant reduction in 20∶4n−6 and 22∶5n−3 compared with the ovolacto vegetarian, high meat‐eater, and moderate meat‐eater groups. Bivariate analysis results showed that MPV was significanly positively correlated with platelet PL 18∶2n−6 (P=0.048) and negatively correlated with 20∶3n−6 (P=0.02), 20∶5n−3 (P=0.005), and 22∶5n−3 (P<0.0001), respectively. In a multiple linear regression analysis, after controlling for potential confounding factors such as dietary group, age exercise, body mass index, and dietary polyunsaturated and saturated fat, cholesterol, carbohydrate, and fiber intake, the MPV was still strongly negatively correlated with platelet PL 20∶3n−6 (P=0.003) and 22∶5n−3 (P=0.001). The present data suggest that 20∶5n−3 and 20∶3n−6 may play a role in the structural function of the platelet membrane.
Anandamide and other N‐acylethanolamines in human tumors
Authors: Schmid Patricia C. , Wold Lester E. , Krebsbach Randy J. , Berdyshev Evgueni V. , Schmid Harald H. O.
Published: November 2006

Long‐chain N‐acylethanolamines (NAE), including the endocannabinoid, anandamide, accumulate in mammalian tissues under a variety of pathological conditions. They have also been shown to inhibit the growth of various cancer cell lines in vitro. Here, we report the presence, in widely differing amounts (3.88–254.46 pmol/μmol lipid P), of NAE and their precursor phospholipids in various human tumors and some adjacent unaffected tissue. Anandamide ranged from 1.5 to 48% of total NAE, and incubation of tissue homogenates suggested possible NAE biosynthesis by both the established transacylation‐phosphodiesterase pathway via N‐acyl PE and by direct N‐acylation of ethanolamine.
Clinical trial results support a preference for using CLA preparations enriched with two isomers rather than four isomers in human studies
Authors: Gaullier Jean‐Michel , Berven Grethe , Blankson Henrietta , Gudmundsen Ola
Published: November 2006

CLA mixtures are now commercially available. They differ from each other with respect to their content of CLA isomers and their degree of purification. As a group of natural FA, CLA have been widely assumed to be safe. However, the suspected presence of both impurities and particular isomers might induce undesirable side effects. Despite this potential health risk, only a few CLA preparations have been tested under rigorous conditions for clinical efficacy and safety. Based on the limited results available, it is possible to suggest that preparations enriched in c9,t11 and t10,c12 isomers are preferable for human consumption compared to preparations containing four isomers, in terms both of safety and efficacy.
In vitro desaturation and elongation of rumenic acid by rat liver microsomes
Authors: Berdeaux O. , Gnädig S. , Chardigny J. M. , Loreau O. , Noël J. P. , Sébédio J. ‐L.
Published: November 2006

Various nutritional studies on CLA, a mixture of isomers of linoleic acid, have reported the occurrence of conjugated long‐chain PUFA after feeding experimental animals with rumenic acid, 9c,11t–18∶2, the major CLA isomer, probably as a result of successive desaturation and chain elongation. In the present work, in vitro studies were carried out to obtain information on the conversion of rumenic acid. Experiments were first focused on the in vitro Δ6‐desaturation of rumenic acid, the regulatory step in the biosynthesis of long‐chain n−6 PUFA. The conversion of rumenic acid was compared to that of linoleic acid (9c,12c–18∶2). Isolated rat liver microsomes were incubated with radiolabeled 9c,12c–18∶2 and 9c,11t–18∶2 under desaturation conditions. The data indicated that [1‐14C]9c,11t–18∶2 was a poorer substrate for Δ6‐desaturase than [1‐14C]‐9c,12c–18∶2. Next, in vitro elongation of 6c,9c,11t–18∶3 and 6c,9c,12c–18∶3 (γ‐linolenic acid) was investigated in rat liver microsomes. Under elongation conditions, [1‐14C]6c,9c,11t–18∶3 was 1.5‐fold better converted into [3‐14C]8c,11c,13t–20∶3 than [1‐14C]6c,9c,12c–18∶3 into [3‐14C]8c,11c,14c–20∶3. Finally, in vitro Δ5‐desaturation of 8c,11c,13t–20∶3 compared to 8c,11c,14c–20∶3 was investigated. The conversion level of [1‐14C]8c,11c,13t–20∶3 into [1‐14C]5c,8c,11c,13t–20∶4 was 10 times lower than that of [1‐14C]8c,11c,14c–20∶3 into [1‐14C]5c,8c,11c,14c–20∶4 at low substrate concentrations and 4 times lower at the saturating substrate level, suggesting that conjugated 20∶3 is a poor substrate for the Δ5‐desaturase.
Tuna fishmeal as a source of DHA for n−3 PUFA enrichment of pork, chicken, and eggs
Authors: Howe Peter R. C. , Downing Jeffrey A. , Grenyer Brin F. S. , Grigonis‐Deane Elizabeth M. , Bryden Wayne L.
Published: November 2006

Enriching foods with long‐chain n−3 PUFA (LC n−3 PUFA) is an important approach to increasing the dietary intake of these beneficial nutrients. Enrichment of meat and eggs can be achieved by adding flaxseed, fish oil, or fishmeal to pig or poultry feeds. However, utilization of these sources, particularly fishmeal, has been limited by concerns about adverse effects on sensory qualities. In this study, we evaluated the use of PorcOmegaTM (POM), a stabilized tuna fishmeal formulation, as a source of DHA for enrichment of pork and poultry products. Pigs, broilers, and laying hens were fed rations containing varying levels of POM for varying time periods, and its impact on the LC n−3 PUFA content and sensory qualities of cooked meat and eggs was examined. Pork and chicken products, including chops, sausages, and eggs, with substantially increased (up to sevenfold) levels of LC n−3 PUFA (predominantly DHA) were achieved by including up to 10% POM in rations. The increases were retained after cooking. Some sensory deficits were noted when using higher levels of POM (exceeding 15% in meat and 10% in eggs). However, at modest rates of feeding (5–10% POM), palatable meat and eggs were obtained with worthwhile levels of enrichment. The fishmeal feeding strategy used in this study offers a viable means of producing a range of alternative dietary sources of LC n−3 PUFA.
Rapid and improved method for the determination of bile acids in human feces using MS
Authors: Perwaiz Shahid , Mignault Diane , Tuchweber Beatriz , Yousef Ibrahim M.
Published: November 2006

A simple method for the determination of bile acids in adult human fecal samples using GC‐MS is described. Bile acids are directly extracted from feces by ethanol (95%) containing 0.1 N NaOH. Extracts are purified by passage through a reversed‐phase C18 silica cartridge and then analyzed by GC‐MS. The present study has shown that lyophilized human feces contain mainly free bile acids, with lithocholic acid (LCA) and deoxycholic acid (DCA) as the major bile acids; however, isomers of LCA and DCA, keto‐bile acids, and cholic acid are also present. Any traces of conjugated bile acids are hydrolyzed before the C18 extraction by deconjugating enzymes, which are present in feces and are activated by the addition of water during the homogenization step. Thus, the analysis of fecal bile acids can be performed without the hydrolysis step in less than 4 h in comparison to traditional techniques, which usually require at least 48 h.
Digestion and assimilation features of dietary DAG in the rat small intestine
Authors: Kondo Hidehiko , Hase Tadashi , Murase Takatoshi , Tokimitsu Ichiro
Published: November 2006

Several recent studies have demonstrated that dietary DAG oil rich in 1,3‐species suppresses the postprandial increase of serum TAG level and decreases body fat accumulation, compared with TAG oil. To clarify the mechanisms underlying the beneficial effects of DAG, we investigated the metabolic features of DAG in the small intestine with regard to the digestion pathway in the lumen and the TAG‐synthesis pathway in the mucosa. When intraduodenally infused as an emulsion, TAG was digested to 1,2‐DAG, 2‐MAG, and FFA, whereas 1,3‐DAG was digested to 1(3)‐MAG and FFA. When assessed by the incorporation of [1‐14C]linoleic acid in lipids, the mucosal TAG‐synthesis was significantly reduced by DAG infusion compared with TAG infusion. However, the mucosal 1,3‐DAG synthesis was remarkably increased in the DAG‐infused rats. The total amount of mucosal 1,3‐DAG was also increased (4.5‐fold) after DAG infusion compared with that after TAG infusion. Next, we examined the synthesis pathway of 1,3‐DAG. In cultures of the everted intestinal sacs, 1,3‐DAG production required the presence of 1‐MAG, suggesting that the 1,3‐DAG synthesis was due to acylation of 1(3)‐MAG in the DAG‐infused rats. Furthermore, measurements of DAG acyltransferase activity indicated that 1,3‐DAG was little utilized in TAG synthesis. These findings suggest that features of 1,3‐DAG digestion and assimilation in the intestine may be responsible for the reduction of the postprandial serum TAG level by dietary DAG.
Effects of dietary thermoxidized fats on expression and activities of hepatic lipogenic enzymes in rats
Authors: Eder Klaus , Suelzle Andrea , Skufca Peter , Brandsch Corinna , Hirche Frank
Published: November 2006

This study was undertaken to investigate the effect of dietary oxidized fats on the relative mRNA concentrations and the activities of fatty acid synthase (FAS) and glucose‐6‐phosphate dehydrogenase (G6PDH) in the liver of rats treated with vitamin E or selenium. Two experiments with male Sprague‐Dawley rats were carried out. The first experiment included eight groups of rats fed diets with either fresh fat or three different types of oxidized fat, preparated by heating at temperatures of 50, 105, or 190°C, over a period of 6 wk. The diets contained either 25 or 250 mg α‐tocopherol equivalents per kg. The second experiment included four groups of rats fed diets with fresh fat or oxidized fat, heated at a temperature of 55°C, containing either 70 or 570 μg selenium per kg, over a period of 8 wk. Feeding the diets with oxidized fats led to a significant overall reduction of the relative mRNA concentrations and the activities of FAS and G6PDH in both experiments. The effects of the oxidized fats on mRNA concentrations and activities of these enzymes were independent of the dietary concentrations of vitamin E or selenium. Moreover, in both experiments the rats whose diet contained the oxidized fats had significantly lower concentrations of TG in liver, plasma, and VLDL than the rats whose diet contained fresh fat. The study suggests that oxidized fats contain substances that suppress gene expression of lipogenic enzymes in the liver.
Characterization of glycerophosphocholine phosphodiesterase activity and phosphatidylcholine biosynthesis in cultured retinal microcapillary pericytes. Effect of adenosine and endothelin‐1
Authors: Anfuso Carmelina D. , Sipione Simonetta , Lupo Gabriella , Ragusa Nicolò , Alberghina Mario
Published: November 2006

In pericytes from bovine retina, the enzyme glycerophosphocholine phosphodiesterase, catalyzing the hydrolysis of sn‐glycero‐3‐phosphocholine to glycero‐3‐phosphate and choline, has been characterized with respect to pH optimum, metal ion dependence, Km, inhibitors, and subcellular localization. In these cells, the natural substrate sn‐glycero‐3‐phosphocholine was present at relatively high concentration (6.4±1.2 nmol/mg protein), and the EDTA‐sensitive phosphodiesterase activity was also found to be markedly high (9.80±1.5 nmol/min/mg protein) compared to the estimated in liver and brain (1–3 nmol/min/mg protein) or in renal epithelial cell culture (0.27 nmol/min/mg protein). The reaction conditions were in general agreement with those found earlier in brain and other tissues. The majority of the enzyme specific activity was located in the plasma membrane, whereas a minor part was present in the microsomal fraction. The physiological significance of the high catabolic phosphodiesterase activity in these cells may be related to the tranfer, followed by deacylation, of lysophosphatidylcholine from the bloodstream to nervous tissue. In addition, capillary pericytes in culture were able to incorporate 3H‐choline rapidly into choline‐containing soluble phosphorylated intermediates and into phosphatidylcholine. To find a positive and negative effector on phosphatidylcholine formation, adenosine, an important intercellular mediator in the retina in response to alterations in oxygen delivery, and endothelin‐1, a potent paracrine mediator present at the blood‐brain and blood‐retina barrier, were tested. The cells cultured for 1 or 24 h in a medium containing adenosine at concentrations of 10−6 and 10−4 M showed significant reduction in 3H‐choline incorporation compared to control cultures, whereas endothelin‐1, at a concentration of 10 and 100 nM, caused stimulation of phosphatidylcholine biosynthesis. These findings provide evidence that both agonists may modulate phosphatidylcholine metabolism in pericytes.
Photochemical oxidation and autoxidation of chlorophyll phytyl side chain in senescent phytoplanktonic cells: Potential sources of several acyclic isoprenoid compounds in the marine environment
Authors: Rontani Jean‐François , Rabourdin Adélaïde , Marchand Daphné , Aubert Claude
Published: November 2006

Visible light‐induced degradation of the chlorophyll phytyl side chain was studied in senescent cells of two phytoplanktonic strains (Skeletonema costatum and Thalassiosira weissflogii). Particular attention was paid to the induction of autoxidation processes on the phytyl chain and its photoproducts by photochemically produced hydroperoxides. The combination of photochemical oxidation and autoxidation reactions resulted in the production of several acyclic isoprenoid compounds that have been unambiguously identified by comparison of their retention times and mass spectra with those of appropriate standards. Various mechanisms are proposed to explain the formation of these oxidation products. These processes appear to be potential sources of numerous oxidized acyclic isoprenoids that previously have been detected in lacustrine and marine environments. Some oxidation products newly described or whose presence in natural samples was never reported in the literature were then sought in particulate matter, sediment, and microbial mat samples. The results obtained supported the significance of photochemical oxidation and autoxidation of phytoplanktonic chlorophyll phytyl side chain in the marine environment.
Protective action of CLA against oxidative inactivation of paraoxonase 1, an antioxidant enzyme
Authors: Su Nguyen‐Duy , Liu Xi‐Wen , Kim Mee Ree , Jeong Tae‐Sook , Sok Dai‐Eun
Published: November 2006

The effect of CLA on paraoxonase 1 (PON1), one of the antioxidant proteins associated with HDL, was investigated for its protective action against oxidative inactivation as well as its stabilization activity. When cis‐9 (c9),trans‐11 (t11)‐CLA and t10,c12‐CLA were examined for their protective activity against ascorbate/Cu2−‐induced inactivation of PON1 in the presence of Ca2+, two CLA isomers exhibited a remarkable protection (Emax, 71–74%) in a concentration‐dependent manner (50% effective concentration, 3–4 μM), characterized by a saturation pattern. Such a protective action was also reproduced with oleic acid, but not linoleic acid. Rather, linoleic acid antagonized the protective action of CLA isomers in a noncompetitive fashion. Additionally, the two CLA isomers also protected PON1 from oxidative inactivation by H2O2 or cumene hydroperoxide. The concentration‐dependent protective action of CLA against various oxidative inactivation systems suggests that the protective action of CLA isomers may be mediated through their selective binding to a specific binding site in a PON1 molecule. Separately, the inactivation of PON1 by p‐hydroxymercuribenzoate (PHMB), a modifier of the cysteine residue, was also prevented by CLA isomers, suggesting the possible existence of the cysteine residue in the binding site of CLA. The c9,t11‐CLA isomer seems to be somewhat more effective than t10,c12‐CLA in protecting against the inactivation of PON1 by either peroxides or PHMB, in contrast to the similar efficacy of these two CLA isomers in preventing ascorbate/Cu2+‐induced inactivation of PON1. Separately, CLA isomers successfully stabilized PON1, but not linoleic acid. These data suggest that the two CLA isomers may play a beneficial role in protecting PON1 from oxidative inactivation as well as in its stabilization.
Vaccenic acid (t11–18∶1) is converted to c9,t11‐CLA in MCF‐7 and SW480 cancer cells
Authors: Miller Aine , McGrath Emma , Stanton Catherine , Devery Rosaleen
Published: November 2006

The aims of this study were to determine whether vaccenic acid (VA; t11–18∶1) is converted to c9,t11‐CLA in human mammary (MCF‐7) and colon (SW480) cancer cell lines and whether VA influences cell viability and other CLA‐bioresponsive markers. When cells were incubated in the presence of VA at concentrations of 5 to 20 μg/mL, both VA and c9,t11‐CLA increased in cellular lipids in a dose‐dependent manner. After 4 d of incubation of SW480 and MCF‐7 cells with VA (20 μg/mL), c9,t11‐CLA increased from undetectable levels to 8.57 and 12.14 g/100 g FAME in cellular lipids, respectively. VA supplementation for 4 d at 5, 10, and 15 μg/mL had no effect on cell growth, whereas 20 μg/mL significantly (P<0.05) reduced cell growth in both cell lines. VA (20 μg/mL) treatment induced DNA fragmentation and significantly (P<0.05) depeleted cytosolic GSH levels in the SW480 cell line after 4 d of incubation, suggesting that apoptosis was the mode of cell death induced by VA. Both VA and c9,t11‐CLA reduced (P<0.05) total ras expression in SW480 cells. 14C‐Arachidonic acid uptake into the MG fraction was significantly increased (P<0.05) in both cell lines while uptake into the phospholipid fraction decreased in response to VA. VA treatment significantly (P<0.05) increased 8‐epi‐prostaglandin F2α in both cell lines. The data indicate that growth suppression and cellular responses of both cells lines are likely mediated by VA desaturation to c9,t11‐CLA via Δ9‐desaturase.
Transfer of arachidonic acid from lymphocytes to macrophages
Authors: Peres C. M. , Sampaio S. C. , Cury Y. , Newsholme P. , Curi R.
Published: November 2006

The incorporation and oxidation of arachidonic acid (AA) by rat lymphocytes (LY), the transfer of AA from LY to rat macrophages (Mϕ) in co‐culture, and the subsequent functional impact on Mϕ phagocytosis were investigated. The rate of incorporation of [1‐14C]AA by untreated‐LY and TG (thioglycolate treated)‐LY (TG‐LY) was 158±8 nmol/1010 LY per h for both untreated‐LY and TG‐LY. The oxidation of AA was 3.4‐fold higher in TG‐LY as compared with untreated cells. LY from TG‐injected rats had a 2.5‐fold increase in the oxidation of palmitic (PA), oleic (OA), and linoleic (LA) acids. After 6 h of incubation, [14C] from AA was distributed mainly into phospholipids. The rate of incorporation into total lipids was 1071 nmol/1010 cells in untreated‐LY and 636 nmol/1010 cells in TG‐LY. [14C]AA was transferred from LY to co‐cultured Mϕ in substantial amounts (8.7 nmol for untreated and 15 nmol per 1010 for TG cells). Exogenously added AA, PA, OA, and LA caused a significant reduction of phagocytosis by resident cells. Mϕ co‐cultured with AA‐preloaded LY showed a significant reduction of the phagocytic capacity (about 40% at 35 μM). LY preloaded with PA, LA, and OA also induced a reduction in phagocytic capacity of co‐cultured Mϕ. TG treatment abolished the AA‐induced inhibition of phagocytosis in Mϕ co‐cultured with TG‐LY. Therefore, the transfer of AA between leukocytes is a modulated process and may play an important role in controlling inflammatory and immune response.
Properties of lysophosphatidylcholine acyltransferase from Brassica napus cultures
Authors: Furukawa‐Stoffer Tara L. , Boyle Riley M. , Thomson Amber L. , Sarna Magdalena A. , Weselake Randall J.
Published: November 2006

Acyl‐CoA:lysophosphatidylcholine acyltransferase (LPCAT; EC 2.3.1.23) catalyzes the acyl‐CoA‐dependent acylation of lysophosphatidylcholine (LPC) to produce PC and CoA. LPCAT activity may affect the incorporation of fatty acyl moieties at the sn‐2 position of PC where PUFA are formed and may indirectly influence seed TAG composition. LPCAT activity in microsomes prepared from microspore‐derived cell suspension cultures of oilseed rape (Brassica napus L. cv Jet Neuf) was assayed using [1‐14C]acyl‐CoA as the fatty acyl donor. LPCAT activity was optimal at neutral pH and 35°C, and was inhibited by 50% at a BSA concentration of 3 mg mL−1. At acyl‐CoA concentrations above 20 μM, LPCAT activity was more specific for oleoyl (18∶1)‐CoA than stearoyl (18∶0)‐ and palmitoyl (16∶0)‐CoA. Lauroyl (12∶0)‐CoA, however, was not an effective acyl donor. LPC species containing 12∶0, 16∶0, 18∶0, or 18∶1 as the fatty acyl moiety all served as effective acyl acceptors for LPCAT, although 12∶0‐LPC was somewhat less effective as a substrate at lower concentrations. The failure of LPCAT to catalyze the incorporation of a 12∶0 moiety from acyl‐CoA into PC is consistent with the tendency of acyltransferases to discriminate against incorporation of this fatty acyl moiety at the sn‐2 position of TAG from the seed oil of transgenic B. napus expressing a medium‐chain thioesterase.
A glucosylceramide with a novel ceramide and three novel ceramides from the basidiomycete Cortinarius umidicola
Authors: Liu Ji‐Kai , Hu Lin , Dong Ze‐Jun
Published: November 2006

A glucosylceramide with novel ceramide and three novel ceramide homologs were isolated from the basidiomycete Cortinarius umidicola and structurally characterized. The ceramide portion of the glucocerebroside consists of a rare (4E,8E)‐9‐methyl‐4,8‐sphingadienine sphingoid base. In contrast, the three ceramide homologs, while having the same sphingoid base, contain as FA residues 2‐hydroxydocosanoic acid, 2‐hydroxytricosanoic acid, and 2‐hydroxytetracosanoic acid.
Recoveries of rat lymph FA after administration of specific structured13C‐TAG
Authors: Vistisen Bodil , Mu Huiling , Høy Carl‐Erik
Published: November 2006

The potential of the specific structured TAG MLM [where M‐caprylic acid (8∶0) and L=linoleic acid (18∶2n−6)] is the simultaneous delivery of energy and EFA. Compared with long‐chain TAG (LLL), they may be more rapidly hydrolyzed and absorbed. This study examined the lymphatic recoveries of intragastrically administered L*L*, M*M*M*, ML*M, and ML*L*(where*=13C‐labeled FA) in rats. Lymph lipids were separated into lipid classes and analyzed by GC combustion isotope ratio MS. The recoveries of lymph TAG 18∶2n‐6 8 h after administration of L*L*L*, ML*M, and ML*L*were 38.6, 48.4, and 49.1%, respectively, whereas after 24 h the recoveries were approximately 50% in all experimental groups. The exogenous contribution to lymph TAG 18∶2n‐6 was approximately 80 and 60% at maximum absorption of the specific structured TAG and L*L*L*, respectively, 3–6 h after administration. The tendency toward more rapid recovery of exogenous long‐chain FA following administration of specific structured TAG compared with long‐chain TAG was probably due to fast hydrolysis. The lymphatic recovery of 8∶0 was 2.2% 24 h after administration of M*M*M*. This minor lymphatic recovery of exogenous 8∶0 was probably due to low stimulation of chylomicron formation. These results demonstrate tendencies toward faster lymphatic recovery of long‐chain FA after administration of specific structured TAG compared with long‐chain TAG.
TG containing stearic acid, synthesized from coconut oil, exhibit lipidemic effects in rats similar to those of cocoa butter
Authors: Rao Reena , Lokesh Belur R.
Published: November 2006

Lipase‐catalyzed interesterification was used to prepare structured TG from coconut oil TG by partially replacing some of the atherogenic saturated FA with stearic acid, which is known to have a neutral effect on lipid levels in the body. The level of stearic acid was increased from 4% in the native coconut oil to 40% in the structured lipids, with most of the stearic acid being incorporated into the sn−1 and sn−3 positions of TG. When structured lipids were fed to rats at a 10% level for a period of 60 d, a 15% decrease in total cholesterol and a 23% decrease in LDL cholesterol levels in the serum were observed when compared to those fed coconut oil. Similarly, the total and free cholesterol levels in the livers of the rats fed structured lipids were lowered by 31 and 36%, respectively, when compared to those fed coconut oil. The TG levels in the serum and in the liver showed decreases of 14 and 30%, respectively, in animals fed structured lipids. Rats fed cocoa butter and structured lipids having a similar amount of stearic acid had similar lipid levels in the serum and liver. These studies indicated that the atherogenic potential of coconut oil lipids can be reduced significantly by enriching them with stearic acid. This also changed the physical properties of coconut oil closer to those of cocoa butter as determined by DSC.
Enzyme‐resistant fractions of beans lowered serum cholesterol and increased sterol excretions and hepatic mRNA levels in rats
Authors: Han Kyu‐Ho , Fukushima Michihiro , Kato Teruhiko , Kojima Michiyuki , Ohba Kiyoshi , Shimada Ken‐ichiro , Sekikawa Mitsuo , Nakano Masuo
Published: November 2006

Feeding rats beans with resistant starch reduces their serum cholesterol concentration; however, the mechanism by which this occurs is not fully understood. We examined the effects of enzyme‐resistant fractions of adzuki (Vigna angularis) and tebou (Phaseolus vulgaris, var.) beans on serum cholesterol and hepatic mRNA in rats. Rats were fed a cholesterol‐free diet with 50 g of cellulose powder (CP)/kg, 50 g of an enzyme‐resistant fraction of adzuki starch (AS)/kg, or 50 g of an enzyme‐resistant fraction of tebou starch (TS)/kg diet for 4 wk. There were no significant differences in body weight, liver weight, and cecum contents among the groups, nor was there a significant difference in food intake among the groups. The levels of serum total cholesterol, VLDL + intermediate density lipoprotein + LDL‐cholesterol, and HDL cholesterol in the AS and TS groups were significantly (P<0.05) lower than in the CP group throughout the feeding period. Total hepatic cholesterol in the CP group was significantly (P<0.05) lower than in the AS and TS groups, fecal cholesterol excretion in the TS group was significantly (P<0.05) greater than in the CP and AS groups, and the fecal total bile acid concentrations in the AS and TS groups were significantly (P<0.05) higher than in the CP group. Cecal acetate, propionate, and n‐butyrate concentrations in the AS and TS groups were significantly (P<0.05) higher than in the CP group. The level of hepatic scavenger receptor class B1 (SR‐B1) mRNA in the TS group was significantly (P<0.05) higher than in the CP group, and the levels of hepatic cholesterol 7α‐hydroxylase mRNA in the AS and TS groups were significantly (P<0.05) higher than in the CP group. These results suggest that AS and TS have a serum cholesterol‐lowering function due to the enhanced levels of hepatic SR‐B1 and cholesterol 7α‐hydroxylase mRNA.