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We demonstrate real-time transmission of 16 Tb/s (80x200Gb/s) over 1020km TeraWave ULL fiber with 170km span length using the world's first 200Gb/s CFP2-DCO module with a record low power consumption less than 0.1W/Gbps.
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BACKGROUND: Mindfulness training is a promising treatment approach in adult ADHD. However, there has not yet been a randomized controlled trial comparing mindfulness to an active control condition. In this study, we assessed the efficacy of a mindfulness training program (MAP) compared to structured psychoeducation (PE). METHODS: After randomization 81 medication-free adult ADHD patients participated either in an 8-week MAP or PE group program. At baseline (T1), after 8 weeks (T2) and after 8 months (T3), severity of ADHD and associated symptoms (depression, general psychopathology, quality of life) were measured with the Conner's ADHD Rating Scales (CAARS), the Beck Depression Inventory (BDI), the Brief Symptom Inventory (BSI) and the SF-36 by self and blind observer ratings. RESULTS: Both groups showed significant pre-post improvements in observer-rated Inattention scale (p < .001, partial η2 = 0.18) and in associated symptomatology, which persisted through 6 months of follow-up. There were no significant differences regarding symptom reduction between the treatment groups. Women benefited more compared to men irrespective of treatment group. Men showed the most pronounced changes under MAP. CONCLUSIONS: In the current study, MAP was not superior to PE regarding symptom reduction in adult ADHD. Both interventions, mindfulness meditation and PE, were efficacious in reducing symptom load in adult ADHD. Furthermore in exploratory post hoc tests the study provides evidence for a potential gender-specific treatment response in adult ADHD.
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Trastorno por Déficit de Atención con Hiperactividad/rehabilitación , Atención Plena/métodos , Educación del Paciente como Asunto/métodos , Resultado del Tratamiento , Inhibidores de Captación Adrenérgica/uso terapéutico , Adulto , Clorhidrato de Atomoxetina/uso terapéutico , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Autoinforme , Índice de Severidad de la Enfermedad , Caracteres SexualesRESUMEN
We demonstrate unrepeatered transmission of 8x128Gb/s PDM-QPSK signals over a 515k-m fiber link. This ultra-long distance of 800 Gb/s unrepeatered transmission in a single fiber configuration is achieved by employing enabling techniques such as large-effective-area ultra-low-attenuation fibers, co-propagating and counter-propagating 2nd-order-pumped distributed Raman amplification, and remote optically pumped amplifier (ROPA). The ROPA itself is also counter-propagating 2nd-order Raman pumped. The designs and characteristics of the ROPA and 2nd-order pumped distributed Raman amplification are described, and optimization of the transmission performance of this ultra-long reach 800Gb/s unrepeatered transmission fiber link is discussed in this paper.
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A meta-analysis based on the results from 13 selected publications was performed to assess the effect of dietary fat supplementation (quantity and fatty acid composition) on α-tocopherol (TOL) concentration in 4 pig tissues (blood, liver, muscle, and adipose tissue). Dietary fat supplementation was defined by the quantity of fat added to the basal diet and its fatty acid profile. After standardization of tissue TOL concentration (as the dependent variable), statistical analyses were performed using multiple nonlinear regression, data partitioning, and partial least squares regression with 7 predictor variables including added vitamin E (VE), added fat, PUFA (% fat), MUFA (% fat), SFA (% fat), omega-3 fatty acids (-3; % fat), and omega-6 fatty acids (-6; % fat). The statistical analyses first showed that the VE level in the diet was the main factor that modulates tissue TOL concentration. The dose-response relationship followed a logarithmic curve, with a saturation of tissue TOL concentration in all the studied tissues. Moreover, the amount of dietary fat, at least up to 20%, was not linearly correlated with tissue TOL concentration, considering that the main fatty acid classes, MUFA and, to a lesser extent, SFA, were positively associated with tissue TOL concentrations. Finally, this study suggests that the inclusion of -3 fatty acids in the diet may decrease tissue and, more precisely, blood TOL concentration.
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Tejido Adiposo/metabolismo , Grasas de la Dieta/farmacología , Hígado/metabolismo , Músculo Esquelético/metabolismo , Porcinos/metabolismo , alfa-Tocoferol/metabolismo , Tejido Adiposo/química , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Grasas de la Dieta/análisis , Suplementos Dietéticos , Ácidos Grasos Omega-3/análisis , Ácidos Grasos Omega-3/farmacología , Ácidos Grasos Omega-6/análisis , Ácidos Grasos Omega-6/farmacología , Femenino , Hígado/química , Masculino , Músculo Esquelético/química , Ensayos Clínicos Controlados Aleatorios como Asunto , Análisis de Regresión , Vitamina E/análisis , Vitamina E/farmacología , alfa-Tocoferol/análisisRESUMEN
There has been renewed interest in vitamin D since numerous recent studies have suggested that besides its well-established roles in bone metabolism and immunity, vitamin D status is inversely associated with the incidence of several diseases, e.g., cancers, cardio-vascular diseases, and neurodegenerative diseases. Surprisingly, there is very little data on factors that affect absorption of this fat-soluble vitamin, although it is acknowledged that dietary vitamin D could help to fight against the subdeficient vitamin D status that is common in several populations. This review describes the state of the art concerning the fate of vitamin D in the human upper gastrointestinal tract and on the factors assumed to affect its absorption efficiency. The main conclusions are: (i) ergocalciferol (vitamin D2), the form mostly used in supplements and fortified foods, is apparently absorbed with similar efficiency to cholecalciferol (vitamin D3, the main dietary form), (ii) 25-hydroxyvitamin D (25OHD), the metabolite produced in the liver, and which can be found in foods, is better absorbed than the nonhydroxy vitamin D forms cholecalciferol and ergocalciferol, (iii) the amount of fat with which vitamin D is ingested does not seem to significantly modify the bioavailability of vitamin D3, (iv) the food matrix has apparently little effect on vitamin D bioavailability, (v) sucrose polyesters (Olestra) and tetrahydrolipstatin (orlistat) probably diminish vitamin D absorption, and (vi) there is apparently no effect of aging on vitamin D absorption efficiency. We also find that there is insufficient, or even no data on the following factors suspected of affecting vitamin D bioavailability: (i) effect of type and amount of dietary fiber, (ii) effect of vitamin D status, and (iii) effect of genetic variation in proteins involved in its intestinal absorption. In conclusion, further studies are needed to improve our knowledge of factors affecting vitamin D absorption efficiency. Clinical studies with labeled vitamin D, e.g., deuterated or (13)C, are needed to accurately and definitively assess the effect of various factors on its bioavailability.
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Absorción Intestinal , Vitamina D/análogos & derivados , Vitamina D/farmacocinética , Envejecimiento/metabolismo , Disponibilidad Biológica , Colecalciferol/farmacocinética , Suplementos Dietéticos/análisis , Ergocalciferoles/farmacocinética , Ácidos Grasos/metabolismo , Alimentos Fortificados/análisis , Humanos , Lactonas/metabolismo , Orlistat , Factores de Riesgo , Sacarosa/análogos & derivados , Sacarosa/metabolismo , Vitamina D/metabolismoRESUMEN
1. A trial was designed to assess the effect of fat supplementation (amount and type of fatty acids) on vitamin E bioavailability in adult cockerels. 2. A total of 60 birds were force-fed three different diets: a semi-purified diet without added fat (Control diet) or supplemented with 3% fat as linseed (Linseed diet) or hydrogenated coconut oil (Coconut diet). The three experimental diets were also supplemented with dl-α-tocopheryl acetate to provide 40 mg vitamin E per bird. 3. After one week of depletion, blood was collected from the wing vein before (baseline) and 6, 12, 24 and 96 h after the gavage. Plasma samples were analysed for their α-tocopherol, cholesterol and triglycerides concentrations. 4. Results showed that the addition of 3% fat in the experimental diet increased post-gavage plasma α-tocopherol response by 153% for Linseed diet and by 75% for Coconut diet (P < 0.0001) compared to the Control group. Furthermore, the plasma α-tocopherol response observed with the Linseed diet was 44% greater than that observed with the Coconut diet (P < 0.0001). There was no effect of treatments on either plasma triglycerides (P = 0.91) or cholesterol (P = 0.45) responses. 5. In conclusion, this study shows that the addition of 3% fat to the diet significantly increases dl-α-tocopheryl acetate bioavailability in adult cockerels. Supplementation of fat rich in unsaturated fatty acids also leads to a higher dl-α-tocopheryl acetate bioavailability than fat rich in saturated fatty acids.
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Pollos/metabolismo , Dieta/veterinaria , Grasas de la Dieta/metabolismo , Vitamina E/farmacocinética , Alimentación Animal/análisis , Animales , Disponibilidad Biológica , Colesterol/sangre , Grasas de la Dieta/administración & dosificación , Suplementos Dietéticos/análisis , Relación Dosis-Respuesta a Droga , Nutrición Enteral/veterinaria , Masculino , Distribución Aleatoria , Triglicéridos/sangre , alfa-Tocoferol/sangreRESUMEN
A study was performed in growing pigs to evaluate the efficacy of α-tocopherol (Tol) concentration in plasma, muscle, liver, and adipose tissue following dietary supplementation with vitamin E (VE) and various sources of fat. The trial involved 96 piglets weaned at an average of 28 d of age. Piglets were fed for 2 wk a semipurified diet not supplemented with VE. Piglets were then randomly assigned to 5 isoenergetic semipurified diets with 100 IU/kg VE as dl-α-tocopheryl acetate: a control (CTRL) diet (with no added fat) and 4 other diets containing either 3% linseed oil (LIN), 3% hydrogenated coconut oil (COC), 3% olive oil (OLI), or 3% safflower oil (SAF) representing diets rich in n-3 PUFA, SFA, MUFA, and n-6 PUFA, respectively. After 49 d of treatment, pigs were killed and blood, muscle (longissimus dorsi), adipose tissue, and whole liver (without gallbladder) were collected and analyzed for their Tol concentrations. For all tissues, LIN and SAF diets led to lower (P < 0.02) Tol concentrations as compared to the CTRL diet: -63 and -67%, respectively. α-Tocopherol concentrations in plasma, liver, and adipose tissue were greater (P < 0.001) in the COC group as compared to the CTRL group. The OLI diet led to greater (P < 0.01) liver Tol concentration (+92%) as compared to the CTRL diet but had no significant effect on plasma, muscle, and adipose tissue Tol concentrations. There were significant correlations (P < 0.001) between plasma, muscle, and liver Tol concentrations (r > 0.78). These results show that supplementation with PUFA markedly decreases Tol concentration in blood and tissues of growing pigs, whereas SFA increase Tol content in blood, liver, and adipose tissue. Monounsaturated fatty acids only increase liver Tol concentrations. Therefore, increasing the amount of fat in the diet (from <0.1 to approximately 3.5%) and the type of dietary fatty acids supplemented with VE are key factors with regards to VE concentration in plasma and tissue. The Tol:PUFA needs to be carefully considered to meet the VE pigs requirement and to ensure an optimal Tol meat enrichment.
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Grasas de la Dieta/farmacología , Músculo Esquelético/metabolismo , Plasma/metabolismo , Porcinos/crecimiento & desarrollo , Triglicéridos/farmacología , alfa-Tocoferol/metabolismo , Tejido Adiposo/metabolismo , Animales , Dieta/veterinaria , Ácidos Grasos/farmacología , Hígado/metabolismo , Masculino , Carne/normas , Porcinos/metabolismo , Factores de TiempoRESUMEN
Obesity is associated with a low-grade inflammation which is correlated with an increased secretion of pro-inflammatory cytokines and chemokines by adipose tissue, suspected to contribute to the development of insulin resistance. Because lycopene is mostly stored in adipose tissue and possesses anti-inflammatory properties, we hypothesize that lycopene could reduce the production of proinflammatory markers in adipose tissue. In agreement with this hypothesis, we observed a decrease of inflammatory markers such as IL-6, MCP-1 and IL-1ß at both the mRNA and protein level when explants of epididymal adipose tissue from mice fed with a high-fat diet were incubated with lycopene ex vivo. The same effect was reproduced with explants of adipose tissue preincubated in lycopene and then subjected to TNFα stimulation. The contribution of adipocytes and preadipocytes was evaluated. In both preadipocytes and differentiated 3T3-L1 adipocytes, lycopene preincubation for 24 h decreased the TNFα-mediated induction of IL-6 and MCP-1. Finally, the same results were reproduced with human adipocyte primary cultures. The molecular mechanism was also studied. In transient transfections, a decrease of the luciferase gene reporter under control of NF-κB responsive element was observed for cells incubated in the presence of lycopene and TNFα compared to TNFα alone. The involvement of the NF-κB pathway was confirmed by the modulation of IKKα/ß phosphorylation by lycopene. Altogether, these results showed for the first time a limiting effect of lycopene on adipose tissue proinflammatory cytokine and chemokine production. Such an effect could prevent or limit the prevalence of obesity-associated pathologies, such as insulin resistance.
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Tejido Adiposo/metabolismo , Carotenoides/farmacología , Quimiocinas/biosíntesis , Citocinas/biosíntesis , Inflamación/metabolismo , Células 3T3-L1 , Adipocitos/fisiología , Tejido Adiposo/efectos de los fármacos , Animales , Células Cultivadas , Quimiocina CCL2/biosíntesis , Humanos , Interleucina-1beta/biosíntesis , Interleucina-6/biosíntesis , Licopeno , Ratones , FN-kappa B/fisiología , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
Carotenoids are colored molecules that are widespread in the plant kingdom, but animals cannot synthesize them. Carotenes are long, apolar molecules which require fully functioning digestive processes to be absorbed properly. Hence they could be interesting markers of intestinal absorption and digestion. Indeed, only few tests are available to assess these processes and only the D-xylose tolerance test is routinely used. However D-xylose is a sugar that tests only the absorption of water-soluble compounds and it only tests duodenal absorption. In this study, we have evaluated carotenoids as markers of digestion and absorption. We compared fasting plasma carotenoids concentrations in 21 control subjects, 20 patients with Crohn's disease, and 18 patients with pancreatic cancer. Crohn's disease alters intestinal absorption while pancreatic cancer decreases pancreatic enzyme secretion thus impairing digestion. Results show that all carotenoids are significantly lower in Crohn's and cancer patients as compared to control subjects and the multifactorial analysis shows that this decrease is mostly independent of dietary intake. Interestingly, maldigestion as seen in pancreatic cancer more strongly influences plasma lutein and lycopene concentrations while malabsorption in Crohn's disease acts on other carotenoids. Thus carotenoids could be interesting alternatives for testing and following patients that are suspected of having malabsorption or maldigestion syndromes.
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Carotenoides/sangre , Enfermedad de Crohn/sangre , Ileítis/sangre , Neoplasias Pancreáticas/sangre , Adulto , Anciano , Biomarcadores/sangre , Dieta , Digestión , Femenino , Humanos , Absorción Intestinal , Masculino , Persona de Mediana Edad , Caracteres Sexuales , Encuestas y CuestionariosRESUMEN
OBJECTIVE: (R,R,R)-alpha-tocopherol is a fat-soluble antioxidant vitamin generally ingested with other dietary antioxidants. The objective of this study was to assess whether the main dietary antioxidant classes, that is carotenoids, polyphenols, vitamin C and gamma-tocopherol, affect the intestinal absorption of alpha-tocopherol. METHODS, DESIGN AND SUBJECTS: We evaluated first the effect of different combinations of antioxidants on (R,R,R)-alpha-tocopherol absorption by a human intestinal cell line (Caco-2 clone TC7). Then we compared the effect of two doses of a dietary antioxidant (lutein) on the postprandial chylomicron alpha-tocopherol responses to an alpha-tocopherol-rich meal. Eight healthy men ate two similar meals in a random order at a 1 month interval. The meals contained 24 mg alpha-tocopherol in sunflower oil plus either 18 or 36 mg lutein. Blood samples were collected during the postprandial periods to compare chylomicron alpha-tocopherol responses. RESULTS: A mixture of polyphenols (gallic acid, caffeic acid, (+)-catechin and naringenin) and a mixture of carotenoids (lycopene, beta-carotene and lutein) significantly impaired alpha-tocopherol absorption in Caco-2 cells (P<0.001 and P<0.0001, respectively). The inhibitory effect of gamma-tocopherol was close to significance (P=0.055). In contrast, vitamin C had no significant effect (P=0.158). Naringenin was the only polyphenol that significantly impaired alpha-tocopherol absorption. Postprandial alpha-tocopherol response was weakest at the highest dose of lutein (616+/-280 nmol/l h vs 1001+/-287 nmol/l h). The observed extent of reduction (-38%, P=0.069) supported the inhibitory effect of carotenoids observed in the Caco-2 experiments. CONCLUSION: Naringenin, carotenoids and probably gamma-tocopherol can impair alpha-tocopherol absorption whereas vitamin C and phenolic acids have no effect.
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Antioxidantes/farmacología , Quilomicrones/química , Absorción Intestinal/efectos de los fármacos , Luteína/farmacología , alfa-Tocoferol/farmacocinética , Adulto , Área Bajo la Curva , Ácido Ascórbico/farmacología , Células CACO-2 , Carotenoides/farmacología , Estudios Cruzados , Relación Dosis-Respuesta a Droga , Flavonoides/farmacología , Humanos , Masculino , Fenoles/farmacología , Polifenoles , Periodo Posprandial , gamma-Tocoferol/farmacologíaRESUMEN
Our knowledge about intestinal absorption and cleavage of carotenoids has rapidly grown during the last years. New facts about carotenoid absorption have emerged while some controversies about cleavage are close to end. The knowledge of the absorption and conversion processes is indispensable to understand and interpret the perturbations that can occur in the metabolism of carotenoids and vitamin A. Recently, it has been shown that the absorption of certain carotenoids is not passive - as believed for a long time - but is a facilitated process that requires, at least for lutein, the class B-type 1 scavenger receptor (SR-B1). Various epidemiological and clinical studies have shown wide variations in carotenoid absorption from one subject to another, such differences are now explained by the structure of the concerned carotenoid, by the nature of the food that is absorbed with the carotenoid, by diverse exogenous factors like the intake of medicines or interfering components, by diet factors, by genetic factors, and by the nutritional status of the subject. Recently, the precise mechanism of beta-carotene cleavage by betabeta-carotene 15,15' monooxygenase (EC 1.14.99.36) - formerly called beta-carotene 15,15' dioxygenase (ex EC 1.13.11.21) - has been discovered, and a second enzyme which cleaves asymmetrically the beta-carotene molecule has been found. beta-carotene 15,15' monooxygenase only acts on the 15,15' bond, thus forming two molecules of retinal from one molecule of beta-carotene by central cleavage. Even though the betabeta-carotene 15,15' monooxygenase is much more active on the beta-carotene molecule, a study has shown that it can act on all carotenoids. Searchers now agree that other enzymes that can catalyse an eccentric cleavage of carotenoids probably exist, but under physiological conditions the betabeta-carotene 15,15' monooxygenase is by far the most active, and it is mainly effective in the small bowel mucosa and in the liver. However the conversion of provitamin A carotenoids into vitamin A is only partial, and requires a satisfactory protein status.
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Carotenoides/metabolismo , Absorción Intestinal , Vitamina A/metabolismo , Animales , Disponibilidad Biológica , Carotenoides/sangre , Gatos , Niño , Fibras de la Dieta , Humanos , Recién Nacido , Mucosa Intestinal/enzimología , Intestino Delgado/enzimología , Hígado/enzimología , Licopeno , Oxigenasas de Función Mixta/metabolismo , Estado Nutricional , Farmacocinética , Ratas , Factores de Tiempo , Deficiencia de Vitamina A/metabolismo , Xantófilas/metabolismoRESUMEN
Several planar photonic crystal components topology-optimized for TE-polarized light, including 60 masculine bends, Y-splitters, and 90 masculine bends, have been characterized for the TM polarization. The experimental results are confirmed by finite-difference time-domain calculations. The surprising efficiency for TM-polarized light is found and paves the way for photonic crystal components suitable for both polarizations.
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A photonic crystal waveguide splitter that exhibits ultralow-loss 3-dB splitting for TE-polarized light is fabricated in silicon-on-insulator material by use of deep UV lithography. The high performance is achieved by use of a Y junction, which is designed to ensure single-mode operation, and low-loss 60 degrees bends. Zero-loss 3-dB output is experimentally obtained in the range 1560-1585 nm. Results from three-dimensional finite-difference time-domain modeling with no adjustable parameters are found to be in excellent agreement with the experimental results.
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Planar photonic crystal waveguide structures have been modelled using the finite-difference-time-domain method and perfectly matched layers have been employed as boundary conditions. Comprehensive numerical calculations have been performed and compared to experimentally obtained transmission spectra for various photonic crystal waveguides. It is found that within the experimental fabrication tolerances the calculations correctly predict the measured transmission levels and other major transmission features.
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Topology optimization is used to design a planar photonic crystal waveguide component resulting in significantly enhanced functionality. Exceptional transmission through a photonic crystal waveguide Z-bend is obtained using this inverse design strategy. The design has been realized in a silicon-on-insulator based photonic crystal waveguide. A large low loss bandwidth of more than 200 nm for the bandgap polarization is experimentally confirmed.
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Topology optimization has been used to design a 60 degrees bend in a single-mode planar photonic crystal waveguide. The design has been realized in a silicon-on-insulator material and we demonstrate a record-breaking 200-nm transmission bandwidth with an average bend loss of 0.43+/-0.27 dB for the TE polarization. The experimental results agree well with 3D finite-difference-time-domain simulations.
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We have investigated the properties of TM polarized light in planar photonic crystal waveguide structures, which exhibit photonic band gaps for TE polarized light. Straight and bent photonic crystal waveguides and couplers have been fabricated in silicon-on-insulator material and modelled using a 3D finite-difference-time-domain method. The simulated spectra are in excellent agreement with the experimental results, which show a propagation loss as low as 2.5+/-4 dB/mm around 1525 nm and bend losses at 2.9+/-0.2 dB for TM polarized light. We demonstrate a high coupling for TM polarized light in a simple photonic crystal coupler with a size of ~ 20 m x 20 m. These promising features may open for the realization of ultra-compact photonic crystal components, which are easily integrated in optical communication networks.
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Carotenoids might lower the incidence of several diseases, yet the mechanisms governing their intestinal absorption are still poorly understood. The aim was to identify and study the main factors governing the transfer of carotenoids from emulsion lipid droplets to mixed micelles, presumed to be a key step in carotenoid absorption. An in vitro model was devised to measure the transfer, and a factorial design was applied to identify the main factors affecting the transfer. Experiments were then conducted to assess the effect of physiological variations of the main factors on the transfer efficiency. Finally, different carotenoids were simultaneously incorporated in emulsion lipid droplets to determine whether they interacted during the transfer. The factorial design gave three factors that significantly affected the transfer: type of carotenoid, pH, and bile lipid concentration. The transfer was (i) inversely related to carotenoid hydrophobicity, (ii) maximum between pH 6 and 7, (iii) maximum from 2 mmol/l bile salts, (iv) impaired by other carotenoids in the case of carotenes, but not in the case of xanthophylls. The transfer mainly depends on carotenoid hydrophobicity, pH, and bile lipid concentration. Physiological variations in pH and bile lipid concentration markedly affect the transfer. Both carotenes and xanthophylls can impair the transfer of carotenes, whereas they have apparently no effect on the transfer of xanthophylls.
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Carotenoides/química , Emulsiones/química , Contenido Digestivo/química , Lípidos/química , Micelas , Bilis/química , Humanos , Concentración de Iones de Hidrógeno , Lípidos/análisis , Agua/químicaRESUMEN
We report a reversed-phase high-performance liquid chromatography method which resolves 13 identified carotenoids and nine unknown carotenoids from human plasma. A Nucleosil C18 column and a Vydac C18 column in series are used with an isocratic solvent system of acetonitrile-methanol containing 50 mM acetate ammonium-dichloromethane-water (70:15:10:5, v/v/v/v) as mobile phase at a flow-rate of 2 ml/min. The intra-day (4.5-8.3%) and inter-day (1.3-12.7%) coefficients of variation are suitable for routine clinical determinations.
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Carotenoides/sangre , Cromatografía Líquida de Alta Presión/métodos , Calibración , Humanos , Reproducibilidad de los ResultadosRESUMEN
We aimed to provide basic data on the processing of vitamin A and E in the human gastrointestinal tract and to assess whether the size of emulsion fat globules affects the bioavailability of these vitamins. Eight healthy men received intragastrically two lipid formulas differing in their fat-globule median diameter (0.7 vs. 10. 1 microm. Formulas provided 28 mg vitamin A as retinyl palmitate and 440 mg vitamin E as all-rac alpha-tocopherol. Vitamins were measured in gastric and duodenal aspirates, as well as in chylomicrons, during the postprandial period. The gastric emptying rate of lipids and vitamin A and E was similar. The free retinol/total vitamin A ratio was not significantly modified in the stomach, whereas it was dramatically increased in the duodenum. The proportion of ingested lipid and vitamins was very similar in the duodenal content. The chylomicron response of lipids and vitamins was not significantly different between the two emulsions. Our main conclusions are as follows: 1) there is no significant metabolism of vitamin A and E in the human stomach, 2) the enzyme(s) present in the duodenal lumen is significantly involved in the hydrolysis of retinyl esters, and 3) the size of emulsion fat globules has no major effect on the overall absorption of vitamin A and E.