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1.
Sci Total Environ ; 749: 141463, 2020 Dec 20.
Article de Anglais | MEDLINE | ID: mdl-32827830

RÉSUMÉ

Arctic regions contain large amounts of organic carbon (OC) trapped in soil and wetland permafrost. With climate warming, part of this OC is released to aquatic systems and degraded by microorganisms, thus resulting in positive feedback due to carbon (C) emission. In wetland areas, water bodies are spatially heterogenic and separated by landscape position and water residence time. This represents a hydrological continuum, from depressions, smaller water bodies and lakes to the receiving streams and rivers. Yet, the effect of this heterogeneity on the OC release from the soil and its processing in waters is largely unknown and not accounted for in C cycle models of Arctic regions. Here we investigated the dissolved OC (DOC) biodegradation of aquatic systems along a hydrological continuum located in two discontinuous permafrost sites: in western Siberia and northern Sweden. The biodegradable dissolved OC (BDOC15; % DOC lost relative to the initial DOC concentration after 15 days incubation at 20 °C) ranged from 0 to 20% for small water bodies located at the beginning of the continuum (soil solutions, small ponds, fen and lakes) and from 10 to 20% for streams and rivers. While the BDOC15 increased, the removal rate of DOC decreased along the hydrological continuum. The potential maximum CO2 production from DOC biodegradation was estimated to account for only a small part of in-situ CO2 emissions measured in peatland aquatic systems of northern Sweden and western Siberia. This suggests that other sources, such as sediment respiration and soil input, largely contribute to CO2 emissions from small surface waters of permafrost peatlands. Our results highlight the need to account for large heterogeneity of dissolved OC concentration and biodegradability in order to quantify C cycling in arctic water bodies susceptible to permafrost thaw.


Sujet(s)
Pergélisol , Régions arctiques , Carbone/analyse , Sibérie , Suède
2.
Sci Total Environ ; 737: 139671, 2020 Oct 01.
Article de Anglais | MEDLINE | ID: mdl-32521361

RÉSUMÉ

Despite the importance of surface waters of permafrost landscapes in carbon (C) emission and dissolved C and metal storage and export, the majority of available observations in high latitude aquatic systems deal with punctual or seasonal sampling without accounting for diurnal variations in temperature and primary productivity-respiration cycles. Towards providing comprehensive understanding of diel variations in CO2 emission, organic C and element concentrations in lakes of frozen peatlands, we monitored, each 2 h over 2 days, the water temperature, pH, CO2 fluxes, CO2, CH4, dissolved organic and inorganic carbon (DOC and DIC, respectively), nutrients, carboxylic acids, bacterial number, and major and trace elements in two acidic (pH = 3.6 and 4.0) and humic (DOC = 15 and 35 mg L-1) thermokarst lakes of discontinuous permafrost zone in Western Siberia. We discovered a factor of 2 to 3 higher CO2 concentrations and fluxes during the night compared to daytime in the high-DOC lake. The emission fluxes in the low-DOC lake increased from zero to negative values during the day to highly positive values during the end of night and early morning. The methane concentration varied within a factor of 5 without any link to the diurnal cycle. The bulk of dissolved (< 0.45 µm) hydrochemical parameters remained highly stable with ±10% variation in concentration over 2 days of observation (DOC, DIC, SUVA254nm, carboxylates (formate, oxalate, puryvate and glutarate), Mn, Fe, Al, other trace elements). Concentrations of Si, P, K, Cu varied within ±20% whereas those of Zn and Ni ranged by a factor of 2 to 4 without any link to diurnal pattern. Overall, the impact of diel cycle on CH4, DOC, nutrient and metal concentration was below 10%. However, neglecting night-time period may underestimate net CO2 emission by ca. 30 to 50% in small organic-rich thaw ponds and switch the CO2 exchange from uptake/zero to net emission in larger thermokarst lakes. Given the dominance of large lakes in permafrost regions, the global underestimation of the emission flux may be quite high. As such, monitoring CO2 concentrations and fluxes in thermokarst lakes during months of extended night time (August to October) is mandatory for assessing the net emissions from lentic waters of frozen peatlands.

3.
Lipids ; 52(7): 641-649, 2017 07.
Article de Anglais | MEDLINE | ID: mdl-28547181

RÉSUMÉ

The present study was designed to determine if feeding steers extruded flaxseed and hay (25 and 75%; DM basis) together as a total mixed ration (TMR), or sequentially (non-TMR) would result in different enrichments of polyunsaturated fatty acids (PUFA) and their biohydrogenation intermediates (BHI) in beef adipose tissues [subcutaneous (SC) vs perirenal (PR) fat]. Forty-eight Angus cross steers (325 ± 16 kg) were stratified by weight to six pens, and pens were randomized to either TMR or non-TMR and fed ad libitum for an average of 242 days. The concentrations of α-linolenic acid increased by 18 mol% in both SC and PR in non-TMR steers compared to TMR steers (P < 0.01). trans 18:1 isomers were more concentrated in PR than SC (14.4 vs 9.5 mol%; P < 0.01) and increased by 10 mol% in both fat depots for non-TMR (P < 0.01). Other BHI including non-methylene-interrupted 18:2 (atypical dienes), conjugated linoleic acids and conjugated linolenic acids (CLnA) were affected by diet × tissue interactions (P < 0.01). The CLnA and CLA contents were higher in both fat depots when feeding the non-TMR, but the effect of diet was more pronounced in PR than in SC (P < 0.01). Atypical dienes were highest in PR from non-TMR and lowest in TMR fed steers (4.3 and 3.6 mol%) with SC contents being intermediate. The sequential feeding of lipid supplement can thus profoundly affect the enrichment of PUFA and their BHI in beef fat and their differentially enrichment is also fat depot dependant.


Sujet(s)
Tissu adipeux/composition chimique , Aliment pour animaux , Acides gras insaturés/analyse , Animaux , Bovins , Acides gras insaturés/composition chimique , Lin , Répartition aléatoire , Viande rouge
4.
Meat Sci ; 131: 9-17, 2017 Sep.
Article de Anglais | MEDLINE | ID: mdl-28448838

RÉSUMÉ

The objective of the present experiment was to determine if carcass quality and fatty acid profiles of longissimus thoracis (LT) and hamburger would be affected by feeding steers extruded flaxseed on its own followed by hay (non-TMR) compared to when hay and extruded flaxseed were fed together (TMR). Forty-eight steers in six pens were assigned to TMR or non-TMR for an average of 242days. Dry matter intake was lower for non-TMR versus TMR steers (10.56 vs. 11.42kg/d; P=0.02), but final live weight (610±0.50kg) and average daily gain (1.18±0.02kg/d) did not differ. Compared to TMR, feeding non-TMR enriched LT and hamburger with α-linolenic acid (ALA; 18:3n-3) by 14%, vaccenic acid (VA; t11-18:1) by 44%, rumenic acid (RA; c9,t11-18:2) by 40%, and conjugated linolenic acid (CLnA) by 58%. Overall, feeding extruded flaxseed separately from hay in a non-TMR was more effective at enhancing deposition of ALA, VA, RA and CLnA in beef.


Sujet(s)
Aliment pour animaux/analyse , Bovins/croissance et développement , Acides gras/analyse , Lin , Viande/analyse , Phénomènes physiologiques nutritionnels chez l'animal , Animaux , Composition corporelle , Régime alimentaire/médecine vétérinaire , Acides linoléiques conjugués/analyse , Mâle , Acides oléiques/analyse , Graines , Acide alpha-linolénique/analyse
5.
Oncogene ; 36(15): 2085-2094, 2017 04.
Article de Anglais | MEDLINE | ID: mdl-27694894

RÉSUMÉ

Mechanisms by which NPM-ALK signaling regulates cell migration, invasion and contributes to the oncogenesis of anaplastic large cell lymphoma (ALCL) are not completely understood. In an attempt to identify novel actin signaling pathways regulated by NPM-ALK, a comprehensive phosphoproteome analysis of ALCL cell lines was performed in the presence or absence of NPM-ALK activity. Numerous phosphoproteins involved in actin dynamics including Wiskott-Aldrich syndrome protein (WASp) were regulated by NPM-ALK. Network analysis revealed that WASp is a central component of the NPM-ALK-dependent actin signaling pathway. Here we show that NPM-ALK phosphorylates WASp at its known activation site (Y290) as well as at a novel residue (Y102). Phosphorylation of WASp at Y102 negatively regulates its interaction with Wiskott-Aldrich interacting protein and decreases its protein stability. Phosphorylation of WASp at Y102 enhances anchorage-independent growth and tumor growth in an in vivo xenograft model and enhances invasive properties of ALCL. We show that knock-down of WASp or expression of Y102F mutant of WASp decreases colony formation and in vivo tumor growth. Our results show that WASp is a novel substrate of ALK and has a critical role in regulating invasiveness and oncogenesis of ALCL.


Sujet(s)
Lymphome à grandes cellules anaplasiques/métabolisme , Protein-tyrosine kinases/métabolisme , Protéine du syndrome de Wiskott-Aldrich/métabolisme , Animaux , Carcinogenèse , Domaine catalytique , Lignée cellulaire tumorale , Techniques de knock-down de gènes , Hétérogreffes , Humains , Lymphome à grandes cellules anaplasiques/génétique , Lymphome à grandes cellules anaplasiques/anatomopathologie , Souris , Souris SCID , Phosphorylation , Protéine du syndrome de Wiskott-Aldrich/génétique
6.
Lipids ; 51(12): 1427-1433, 2016 Dec.
Article de Anglais | MEDLINE | ID: mdl-27853932

RÉSUMÉ

Human liver cells (HepG2) were cultured with individual trans (t) 18:1 including t6-, t12-, t13-, t14-, t15- and t16-18:1, and retention times of their Δ-9 desaturation products were determined using 100-m biscyanopropyl-polysiloxane and SLB-IL111 columns. Corresponding peaks were found in beef adipose tissues known to have different delta-9 desaturase activities. Further lines of evidence indicating the presence of Δ-9 desaturation products of t-18:1 isomers in beef fat were developed by analysis of fatty acid methyl esters (FAME) fractionated using Ag+-TLC, and by GC/MS. Some of the Δ-9 desaturation products of t-18:1 have been previously identified in ruminant fat (c9, t12- and c9, t13-18:2). Some of the Δ-9 desaturation products of t-18:1 (c9, t14- and c9, t15-18:2) have been previously tentatively identified as different fatty acids, and for the first time we provide evidence of the presence of c9, t16-18:2, and where t6, c9-18:2 may elute during analysis of FAME from beef fat.


Sujet(s)
Acides gras/analyse , Viande rouge/analyse , Acyl-(acyl-carrier-protein)desaturase/métabolisme , Animaux , Bovins , Chromatographie en phase gazeuse , Cellules HepG2 , Humains , Isomérie
7.
Lipids ; 50(12): 1253-8, 2015 Dec.
Article de Anglais | MEDLINE | ID: mdl-26476931

RÉSUMÉ

The objective of this research was to study the delta-9 desaturation of individual trans (t) fatty acids that can be found in ruminant fat or partially hydrogenated vegetable oils (PHVO) and determine their effects on lipogenic gene expression in adipocytes. It was hypothesized that delta-9 desaturation and lipogenic properties of t-18:1 isomers depend on the position of double bond. Differentiated 3T3-L1 adipocytes were treated with 200 µM of t6-18:1, t9-18:1, t11-18:1, t13-18:1 or t16-18:1, cis (c)-9 18:1 or bovine serum albumin (BSA) vehicle control for 48 h. Cells were then harvested for fatty acid and gene expression analyses using gas chromatography and quantitative PCR respectively. Among t-18:1 isomers, t13-18:1 and t11-8:1 had the greatest percent delta-9 desaturation (44 and 41 % respectively) followed by t16-18:1 and t6-18:1 (32 and 17 % respectively), while c9-18:1 and t9-18:1 did not undergo delta-9 desaturation. Trans9-18:1 up-regulated (P < 0.05) the expression of lipogenic genes including fatty acid synthase and stearoyl-CoA desaturase-1 (P < 0.05), whereas the expression of these genes were not affected with other t-18:1 isomers (P > 0.05). Consistent with gene expression results, t9-18:1 increased the de novo lipogenic index (16:0/18:2n-6) compared with control cells and increased delta-9 desaturation index (c9-16:1/18:0) compared to other t-18:1 isomers (P < 0.05). The current study provides further evidence that the predominant trans fatty acid in PHVO (t9-18:1) has isomer specific lipogenic properties.


Sujet(s)
Adipocytes blancs/enzymologie , Fatty acid desaturases/métabolisme , Fatty acid synthases/métabolisme , Lipogenèse , Acides oléiques/métabolisme , Acyl-(acyl-carrier-protein)desaturase/métabolisme , Acides gras trans/métabolisme , Cellules 3T3-L1 , Adipocytes blancs/métabolisme , Animaux , Survie cellulaire , Matières grasses alimentaires/analyse , Induction enzymatique , Fatty acid synthases/composition chimique , Fatty acid synthases/génétique , Conserves et aliments avec conservateur/analyse , Hydrogénation , Souris , Structure moléculaire , Acides oléiques/composition chimique , Huiles végétales/composition chimique , ARN messager , Acyl-(acyl-carrier-protein)desaturase/composition chimique , Acyl-(acyl-carrier-protein)desaturase/génétique , Stéréoisomérie , Acides gras trans/composition chimique
8.
Article de Anglais | MEDLINE | ID: mdl-25579113

RÉSUMÉ

Polyunsaturated fatty acids typically found in cattle feed include linoleic (LA) and α-linolenic acid (ALA). In the rumen, microbes metabolize these resulting in the formation of biohydrogenation products (BHP), which can be incorporated into meat and milk. Bioactivities of LA-BHP, including conjugated linoleic acid (cis (c) 9,trans (t) 11-18:2 and t10,c12-18:2) and trans fatty acid isomers (t9-, t10- and t11-18:1) have been investigated, but effects of several BHP unique to ALA have not been extensively studied, and most ALA-BHP are not commercially available. The objective of the present research was to develop methods to purify and collect ALA-BHP using silver ion (Ag(+)) chromatography in sufficient quantities to allow for convenient bioactivity testing in cell culture. Fatty acid methyl esters (FAME) were prepared from perirenal adipose tissue from a cow enriched with ALA-BHP by feeding flaxseed. These were applied to Ag(+)-solid phase extraction, and eluted with hexane with increasing quantities of acetone (1, 2, 10, 20%) or acetonitrile (2%) to pre-fractionate FAME based on degree of unsaturation and double bond configuration. Fractions were collected, concentrated and applied to semi-preparative Ag(+)-high performance liquid chromatography (HPLC) for the isolation and collection of purified isomers, which was accomplished using isocratic elutions with hexane containing differing amounts of acetonitrile (from 0.015 to 0.075%). Purified trans-18:1 isomers collected ranged in purity from 88 to 99%. Purity of the ALA-BHP dienes collected, including c9,t13-18:2, t11,c15-18:2 and t10,c15-18:2, exceeded 90%, while purification of other dienes may require the use of other complementary procedures (e.g. reverse phase HPLC).


Sujet(s)
Chromatographie en phase liquide à haute performance/méthodes , Extraction en phase solide/méthodes , Acide alpha-linolénique/isolement et purification , Acides linoléiques conjugués/isolement et purification
9.
Lipids ; 50(2): 195-204, 2015 Feb.
Article de Anglais | MEDLINE | ID: mdl-25544125

RÉSUMÉ

The objective of this research was to study the metabolism of individual trans fatty acids (FAs) that can be found in ruminant fat or partially hydrogenated vegetable oils (PHVO) and determine their effects on FA composition and lipogenic gene expression in adipocytes. Differentiated 3T3-L1 adipocytes were treated with 200 µM of either trans-9-18:1, trans-11-18:1, trans-13-18:1, cis-9-18:1 or BSA vehicle control for 120 h. Trans-9-18:1 increased total cell FA content (µmole/well) compared to other FA treatments, which was mainly related to the accumulation of trans-9-18:1 in the cells. Adipocytes were able to desaturate a significant proportion of absorbed trans-11-18:1 and trans-13-18:1 (~20 and 30% respectively) to cis-9,trans-11-18:2 and cis-9,trans-13-18:2, whereas trans-9-18:1 was mostly incorporated intact resulting in a greater lipophilic index (i.e. decreased mean FA fluidity) of adipocytes. Trans-9-18:1 up-regulated (P < 0.05) the expression of lipogenic genes including acetyl-CoA carboxylase (1.65 fold), FA synthase (1.45 fold), FA elongase-5 (1.52 fold) and stearoyl-CoA desaturase-1 (1.49 fold), compared to the control, whereas trans-11-18:1 and trans-13-18:1 did not affect the expression of these genes compared to control. Our results suggest that the metabolism and lipogenic properties of trans-11-18:1 and trans-13-18:1, typically the most abundant trans FA in beef from cattle fed forage-based diets, are similar and are different from those of trans-9-18:1, the predominant trans FA in PHVO.


Sujet(s)
Adipocytes/métabolisme , Acides gras/métabolisme , Lipogenèse , Cellules 3T3-L1 , Animaux , Bovins , Acides gras/composition chimique , Acides gras/génétique , Régulation de l'expression des gènes , Isomérie , Souris
10.
Meat Sci ; 99: 123-31, 2015 Jan.
Article de Anglais | MEDLINE | ID: mdl-25443972

RÉSUMÉ

Steers were fed grass hay or red clover silage based diets containing flaxseed or sunflower seed as sources of 18:3n-3 and 18:2n-6 respectively. Hamburgers were made from triceps brachii and perirenal or subcutaneous fat. Perirenal-hamburgers contained more polyunsaturated fatty acids (PUFA), several PUFA biohydrogenation intermediates (BHI), and 18:0 (P<0.05). Oxidative stability was similar across hamburgers (P>0.05). Sensory differences were found due to hamburger fat source, but were < one panel unit. Within perirenal-hamburgers, feeding flaxseed increased 18:3n-3 and its BHI (P<0.05), and feeding sunflower seed increased 18:2n-6 and its BHI (P<0.05). Feeding flaxseed increased off-flavour intensity and oxidation in perirenal-hamburgers (P<0.05). Feeding oilseeds in forage based diets while using perirenal fat to make hamburgers provides opportunities to increase PUFA and BHI with potential to impact human health, but control measures need to be explored to limit oxidation and off-flavours when feeding flaxseed.


Sujet(s)
Tissu adipeux , Régime alimentaire , Acides gras insaturés/métabolisme , Acides gras/analyse , Lin , Helianthus , Viande/analyse , Aliment pour animaux , Phénomènes physiologiques nutritionnels chez l'animal , Animaux , Bovins , Compléments alimentaires , Humains , Rein , Peroxydation lipidique , Viande/normes , Muscles squelettiques/métabolisme , Oxydoréduction , Huiles végétales , Graines , Graisse sous-cutanée , Goût
11.
Lipids ; 49(3): 275-86, 2014 Mar.
Article de Anglais | MEDLINE | ID: mdl-24399450

RÉSUMÉ

The current study evaluated the composition and relationships of polyunsaturated fatty acid biohydrogenation products (PUFA-BHP) from the perirenal (PRF) and subcutaneous fat (SCF) of yearling steers fed a 70 % grass hay diet with concentrates containing either sunflower-seed (SS) or flaxseed (FS). Analysis of variance indicated several groups or families of structurally related FA, and individual FA within these were affected by a number of novel oilseed by fat depot interactions (P < 0.05). Feeding diets containing SS increased the proportions of non-conjugated 18:2 BHP (i.e., atypical dienes, AD) and conjugated linoleic acids (CLA) with the first double bond from carbon 7 to 9, trans-18:1 isomers with double bonds from carbon 6 to 12, and these PUFA-BHP had greater proportions in SCF compared to PRF (P < 0.05). Enrichment of conjugated linolenic acids, AD and CLA isomers with the first double bond in position 11 or 12, and t-18:1 isomers with double bonds from carbon 13 to 16 were achieved by feeding diets containing FS, with PRF having greater proportions than SCF (P < 0.05). Principal component analysis visually confirmed interaction effects on these groups/families of FA, and further confirmed or suggested a number of relationships between PUFA-BHP. Feeding SS or FS in a grass hay diet and exploiting adipose tissue differences, therefore, present unique opportunities to differentially enrich a number of PUFA-BHP which seem to have positive health potential in humans (i.e., t11-18:1, c9,t11-18:2 and c9,t11,c15-18:3).


Sujet(s)
Tissu adipeux/métabolisme , Aliment pour animaux , Acides gras insaturés/métabolisme , Lin/composition chimique , Helianthus/embryologie , Hydrogène/métabolisme , Poaceae , Animaux , Bovins , Helianthus/composition chimique
12.
Meat Sci ; 95(1): 98-109, 2013 Sep.
Article de Anglais | MEDLINE | ID: mdl-23669875

RÉSUMÉ

Yearling steers were fed 70:30 forage:concentrate diets for 205 d, with either grass hay (GH) or red clover silage (RC) as the forage source, and concentrates containing either sunflower-seed (SS) or flaxseed (FS), each providing 5.4% oil to diets. Feeding diets containing SS versus FS significantly improved growth and carcass attributes (P<0.05), significantly reduced meat off-flavor intensity (P<0.05), and significantly increased intramuscular proportions of vaccenic (t11-18:1), rumenic (c9,t11-CLA) and n-6 fatty acids (FA, P<0.05). Feeding diets containing FS versus SS produced significantly darker and redder meat with greater proportions of atypical dienes (P<0.05). A significant forage × oilseed type interaction (P<0.05) was found for n-3 FA, α-linolenic acid, and conjugated linolenic acid, with their greatest intramuscular proportions found when feeding the RC-FS diet. Feeding GH versus RC also significantly improved growth and carcass attributes, sensory tenderness (P<0.05) and significantly influenced intramuscular FA composition (P<0.05), but overall, forage effects on FA profiles were limited compared to effects of oilseed.


Sujet(s)
Aliment pour animaux , Phénomènes physiologiques nutritionnels chez l'animal , Lin/composition chimique , Helianthus/composition chimique , Viande/analyse , Graines/composition chimique , Animaux , Bovins , Qualité alimentaire , Humains , Acides linoléiques conjugués/composition chimique , Mâle , Muscles squelettiques/composition chimique , Poaceae/composition chimique , Rumen/composition chimique , Goût , Acide alpha-linolénique/composition chimique
13.
Meat Sci ; 92(3): 210-20, 2012 Nov.
Article de Anglais | MEDLINE | ID: mdl-22546816

RÉSUMÉ

The fatty acid composition of beef and pork has been stigmatized due to their relationships with several diseases from cardiovascular disease to cancer. Meat lipids are, however, one of the few components of meat that can be modified in content and composition, and can present opportunities for value added production and health promotion. Until regulations and policies are in place to define requirements for fatty acid enrichment, however, the process remains relatively academic. Once practical goals are in place for fatty acid enrichment in meat, both theory and practice need to converge for successful production of fatty acid enriched meat. The present review covers aspects of policy in Canada, and requirements for research networks to respond to theoretical and practical challenges associated with production of fatty acid enriched meat. Finally, needs for education and marketing are outlined which must be in place to truly realize a transition of meat lipids from perceived disease and waste to health and opportunity.


Sujet(s)
Régime alimentaire , Acides gras , Aliment enrichi , Santé , Lipides , Viande , Politique nutritionnelle , Animaux , Canada , Humains , Marketing
14.
Meat Sci ; 91(4): 472-7, 2012 Aug.
Article de Anglais | MEDLINE | ID: mdl-22459498

RÉSUMÉ

Dietary lipid effect, as a consequence of protein supplement, on lamb m. longissimus dorsi fatty acid composition was investigated, with emphasis on biohydrogenation intermediates. Crossbred lambs (White Swedish Landrace × Texel) were fed a barley-based diet without (CON) or with protein supplements including peas (PEA), rapeseed cake (RC) or hempseed cake (HC). The HC diet resulted in the highest muscle 22:6n-3 proportion, with the RC diet being similar (P<0.05). Protein supplement did not affect the c9,t11 conjugated linoleic acid (CLA) proportion, however the HC diet increased some minor CLA isomers, including t10,c12 CLA (P<0.05). The t10-18:1 and total trans-18:1 were lowest for the RC diet (P<0.05), likely relating to rumen conditions and precursor availability. The saturated, monounsaturated and branched-chain fatty acids were largely unaffected by protein supplement. In conclusion, feeding the RC diet lowered the t10-18:1 and total trans-18:1 in meat, and modestly increased 22:6n-3 content. The direction of these changes would be beneficial, making the RC diet the preferred protein supplement; however the magnitude of the changes in the present experiment may not be sufficient to have an impact on human health.


Sujet(s)
Brassica rapa/composition chimique , Régime alimentaire , Matières grasses alimentaires/métabolisme , Protéines alimentaires/pharmacologie , Acides gras/métabolisme , Muscles squelettiques/métabolisme , Protéines végétales/pharmacologie , Aliment pour animaux , Animaux , Sélection , Cannabis/composition chimique , Compléments alimentaires , Acides gras monoinsaturés/métabolisme , Acides linoléiques conjugués/métabolisme , Pisum sativum/composition chimique , Ovis , Acides gras trans/métabolisme
15.
Meat Sci ; 90(3): 678-85, 2012 Mar.
Article de Anglais | MEDLINE | ID: mdl-22104254

RÉSUMÉ

Thirty-three young bulls from Tudanca local breed were used to investigate the effect of two production systems (semi-extensive vs. intensive) and two slaughter ages (12 vs. 14months) on meat fatty acid (FA) composition. Longissimus thoracis from semi-extensive animals had a lower percentage of intramuscular fat (p≤0.001), saturated FAs (p≤0.05), trans-18:1 (p≤0.001), n-6/n-3 ratio (p≤0.001) and a higher percentage of branched chain FAs (p≤0.001), polyunsaturated FAs (p≤0.001) and conjugated linoleic acid (CLA) (p≤0.001). Few differences were observed in FA composition between slaughter ages. Hence, meat from semi-extensive animals slaughtered at 12 or 14months displayed a healthier FA profile from a consumer's point of view.


Sujet(s)
Manipulation des aliments/méthodes , Acides linoléiques conjugués/analyse , Viande/analyse , Muscles squelettiques/composition chimique , Abattoirs/normes , Aliment pour animaux , Animaux , Sélection , Bovins , Comportement du consommateur , Régime alimentaire/médecine vétérinaire , Matières grasses alimentaires , Mâle
16.
Anticancer Res ; 30(10): 3951-7, 2010 Oct.
Article de Anglais | MEDLINE | ID: mdl-21036708

RÉSUMÉ

PURPOSE: Mantle cell lymphoma (MCL) is a chemoresistant lymphoma overexpressing the class pi glutathione-S-transferase (GST-pi). The nuclear localisation of GST-pi is induced by chemotherapy and is correlated to cell resistance. In this study, the effect of the Agaricus bisporus lectin (ABL), a GST-pi nuclear transfer inhibitor, on the chemosensitivity of MCL cells was investigated. METHODS: The proliferation of three MCL cell lines was evaluated in the presence of doxorubicin (DOX), cisplatin (CDDP), cytarabine (Ara-C), gemcitabine (GEM) or bortezomib with or without ABL pre-treatment. RESULTS: The cytotoxic activities of CDDP, Ara-C, GEM and bortezomib were increased in all cell lines. The DOX cytotoxic activity was enhanced in two of three cell lines. The inhibition of GST-pi nuclear transfer led to the potentialisation of all drug combinations. CONCLUSION: The inhibition of the nuclear transfer of GST-pi increases the MCL sensitivity to DOX, CDDP, Ara-C, GEM and bortezomib, alone or in combination.


Sujet(s)
Antinéoplasiques/pharmacologie , Protocoles de polychimiothérapie antinéoplasique/pharmacologie , Glutathione S-transferase pi/antagonistes et inhibiteurs , Lymphome à cellules du manteau/traitement médicamenteux , Lymphome à cellules du manteau/enzymologie , Transport nucléaire actif/effets des médicaments et des substances chimiques , Acides boroniques/administration et posologie , Acides boroniques/pharmacologie , Bortézomib , Processus de croissance cellulaire/effets des médicaments et des substances chimiques , Lignée cellulaire tumorale , Cisplatine/administration et posologie , Cisplatine/pharmacologie , Cytarabine/administration et posologie , Cytarabine/pharmacologie , Désoxycytidine/administration et posologie , Désoxycytidine/analogues et dérivés , Désoxycytidine/pharmacologie , Doxorubicine/administration et posologie , Doxorubicine/pharmacologie , Tests de criblage d'agents antitumoraux , Glutathione S-transferase pi/métabolisme , Humains , Lectines/administration et posologie , Lectines/pharmacologie , Lymphome à cellules du manteau/anatomopathologie , Pyrazines/administration et posologie , Pyrazines/pharmacologie ,
17.
Prog Urol ; 20(7): 477-82, 2010 Jul.
Article de Français | MEDLINE | ID: mdl-20656268

RÉSUMÉ

INTRODUCTION: Optical spectroscopy refers to a group of novel technologies that uses interaction of light with tissues to analyze their structure and chemical composition. The objective of this article is to describe these technologies and detail their potential for assessing urological tumors. MATERIAL AND METHODS: It has been shown that optical spectroscopy can accurately analyse multiple solid tumors. Several publications specifically aimed at assessing prostate cancers, renal carcinomas and urothelial tumors. RESULTS: There are three types of spectroscopy that all use light focussed on a tissue and thereafter collect a specific reflected optical signal. Optical spectroscopy can differentiate benign (adenoma or inflammation) and malignant (adenocarcinoma) prostatic tissues. It can also distinguish normal bladder tissue from inflammatory or cancerous cells. Regarding renal tumors, spectroscopy can identify normal and tumoral tissue and differentiate benign and malignant tumors. Its diagnostic accuracy is about 85%. However, reported studies only concentrate on in vitro or ex vivo specimen and the numbers of patients are quite small. CONCLUSION: Optical spectroscopy can be envisioned as an "optical biopsy" tool. Potential applications in the clinical field are promising. Larger studies on in vivo specimen need to be undertaken to confirm phase I preliminary reports.


Sujet(s)
Analyse spectrale Raman , Tumeurs urologiques/anatomopathologie , Conception d'appareillage , Humains , Analyse spectrale Raman/instrumentation
18.
Article de Anglais | MEDLINE | ID: mdl-17728194

RÉSUMÉ

Many problems concerned with the production and the purification of recombinant proteins must be addressed prior to launching an industrial production process. Among these problems, attention is focused on low-level expression that complicates the purification step and can jeopardise the process. The expression of a membrane protein, rP30, of Toxoplasma gondii in the yeast Schizosaccharomyces pombe led to a secretion of only 0.5 microg ml(-1). In order to obtain a sufficient quantity for biochemical characterization and evaluation in vitro diagnostic test development, strategies for both production and purification had to be optimized. First, the influence of four nitrogen sources (three peptones and yeast extract) on the growth rate, but also on the separation between the protein and the components of the fermentation broth was assessed. Second, batch and fed-batch fermentations were compared in terms of final biomass and rP30 concentrations. Third, three different protocols that included fixed and expanded bed ion exchange chromatography were compared for processing a large volume of feedstock. By using the most appropriate strategies, i.e. fed-batch fermentation, capture on EBA cation exchanger and affinity chromatography polishing, a purification factor of 1778 and a yield of 49% were achieved. These performances allowed a 12.5-fold increase for the overall rP30 process productivity.


Sujet(s)
Antigènes de protozoaire/isolement et purification , Protéines de protozoaire/isolement et purification , Protéines recombinantes/isolement et purification , Toxoplasma/métabolisme , Animaux , Antigènes de protozoaire/génétique , Antigènes de protozoaire/métabolisme , Biomasse , Chromatographie d'affinité/méthodes , Fermentation , Protéines de protozoaire/génétique , Protéines de protozoaire/métabolisme , Protéines recombinantes/métabolisme , Schizosaccharomyces/génétique , Schizosaccharomyces/métabolisme , Toxoplasma/génétique
19.
J Clin Gastroenterol ; 38(10): 898-900, 2004.
Article de Anglais | MEDLINE | ID: mdl-15492609

RÉSUMÉ

GOALS: To describe the prevalence and natural history of gastric antral vascular ectasia (GAVE) in patients with end-stage liver disease undergoing orthotopic liver transplantation (OLT). BACKGROUND: GAVE is a well-recognized cause of gastrointestinal hemorrhage. Although 30% of patients with GAVE have liver disease, the prevalence of GAVE in patients with cirrhosis is not known. STUDY: We reviewed clinical records of patients who underwent OLT at our institution from February 1, 1998 to June 2003. Demographic and clinical details were recorded with attention to findings during upper endoscopy before and after OLT. RESULTS: A total of 597 patients underwent OLT, and 345 were evaluated preoperatively with esophagogastroduodenoscopy (EGD). Eight (2.3%) were found to have GAVE before OLT. Three of these eight underwent EGD after OLT, and GAVE was absent in all three. None of the patients with GAVE experienced gastrointestinal bleeding postoperatively. CONCLUSIONS: GAVE was present in nearly 1 in 40 patients with end-stage liver disease who underwent EGD before OLT at our institution and appears to resolve after transplant. These findings are consistent with a previous report documenting resolution of GAVE after OLT.


Sujet(s)
Ectasie vasculaire antrale/diagnostic , Ectasie vasculaire antrale/épidémiologie , Transplantation hépatique , Sujet âgé , Femelle , Gastroscopie , Humains , Défaillance hépatique/chirurgie , Mâle , Adulte d'âge moyen , Prévalence
20.
Ann Rheum Dis ; 63(6): 703-8, 2004 Jun.
Article de Anglais | MEDLINE | ID: mdl-15140778

RÉSUMÉ

BACKGROUND: Diary recording of pain and disabling activities in osteoarthritis (OA) is widely recommended, but, to our knowledge, its impact on symptoms has not been investigated. Exercise programmes have been shown to be effective when patients are closely supervised by nurses or physiotherapists; however, data are lacking on the efficacy of an unsupervised home based exercise regimen in patients with OA. OBJECTIVES: To evaluate the clinical efficacy of patient administered assessment tools and an unsupervised home based exercise programme alone or in combination in patients with OA. METHODS: The study was a 24 week, open cluster randomised controlled trial with a factorial design. Rheumatologists (n = 867) were assigned to four groups according to the treatment given: standardised tools (ST; n = 220), exercises (EX; n = 213), both tools and exercises (ST+EX; n = 213), or usual care (n = 221). Each rheumatologist was to enroll four patients who met the American College of Rheumatology criteria for OA (three with knee OA, one with hip OA). "Tools" consisted of weekly recording of pain and disabling activities in a diary. A home based exercise programme was performed daily at least four times per week with the aid of videotape and booklet. In addition to exercise and assessment, all patients received 12.5 mg or 25 mg of the non-steroidal anti-inflammatory drug rofecoxib once daily. Outcome variables were: pain (measured on a visual analogue scale, 0-100); Western Ontario and McMaster Universities Osteoarthritis Index, function subscale (0-100); and patient assessment of the quality of care (0-100). RESULTS: Overall, 2957 patients with OA (2216 knee, 741 hip) were included. After 24 weeks, both pain and function improved in the ST, EX, ST+EX, and usual care groups (mean (SD) -17 (27), -20 (29), -15 (27), -19 (29); and -11 (19), -12 (19), -10 (19), -11 (20), respectively), without significant differences between groups. However, patients in the EX and ST+EX groups were more likely to agree that their rheumatologist had done his best to preserve their functional and physical activities. CONCLUSION: Although patients' assessments favoured the exercise programme, results from this study failed to demonstrate a short term symptomatic effect of the two non-pharmacological treatments (weekly recording of condition and exercise) in patients with OA concurrently receiving nonsteroidal anti-inflammatory drugs.


Sujet(s)
Traitement par les exercices physiques/méthodes , Coxarthrose/thérapie , Gonarthrose/thérapie , Autosoins/méthodes , Sujet âgé , Femelle , Soins à domicile/méthodes , Humains , Mâle , Adulte d'âge moyen , Mesure de la douleur/méthodes , Observance par le patient , Satisfaction des patients , Résultat thérapeutique
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