Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Dermal absorption and toxicological risk assessment : pitfalls and promises
    Buist, H. - \ 2016
    Wageningen University. Promotor(en): Ruud Woutersen; Ivonne Rietjens, co-promotor(en): J.J.M. van de Sandt. - Wageningen : Wageningen University - ISBN 9789462577275 - 200
    skin - absorption - permeability - in vitro - experiments - exposure assessment - risk assessment - toxicology - biocides - rodenticides - preservatives - disinfection - huid - absorptie - permeabiliteit - in vitro - experimenten - blootstellingsbepaling - risicoschatting - toxicologie - biociden - rodenticiden - conserveermiddelen - desinfectie

    Absorption of toxic substances via the skin is an important phenomenon in the assessment of the risk of exposure to these substances. People are exposed to a variety of substances and products via the skin, either directly or indirectly, while at work, at home or in public space. Pesticides, organic solvents and metalworking fluids are seen to be important contributors to adverse health effects due to occupational exposure via the skin. In daily life, cosmetics, clothing and household products are the most relevant commodities with respect to exposure via the skin.

    Given the importance of skin exposure in the assessment of the risk of toxic substances, the objective of this thesis was to further develop, evaluate and improve methods for including skin absorption data this assessment.

    In this thesis, four factors influencing dermal absorption, namely dermal loading (chapters 3 and 6), irritative/corrosive potential (chapters 3 and 4), frequency of exposure (chapters 3, 4 and 5) and the vehicle used (chapter 5), were investigated in more detail. Furthermore, a model to extrapolate infinite dose absorption data to finite dose conditions, baptized Dermal Absorption Model for Extrapolation (DAME), was developed and tested.

    I

    n chapter 2 of this thesis, the relationship between relative dermal absorption and dermal loading was investigated. Hundred-and-thirty-eight dermal publicly available absorption experiments with 98 substances were evaluated. The results obtained revealed that dermal loading ranged mostly between 0.001 and 10 mg/cm2. In 87 experiments (63%), an inverse relationship was observed between relative dermal absorption and dermal loading. On average, relative absorption at high dermal loading was 33 times lower than at low dermal loading. Known skin irritating and volatile substances less frequently showed an inverse relationship between dermal loading and relative absorption. It was concluded that when using relative dermal absorption in regulatory risk assessment, its value should be determined at or extrapolated to dermal loadings relevant for the exposure conditions being evaluated.

    I

    n chapter 3 of this thesis, a literature search was presented with the aim to investigate whether neglecting the effects of repeated exposure may lead to an incorrect estimate of dermal absorption. The results demonstrated that the effect of repeated versus single exposure does not demonstrate a unique trend. Nevertheless, an increase in daily absorption was frequently observed upon repeated daily exposure. The little information available mostly concerned pharmaceuticals. However, consumers and workers may be repeatedly exposed to other types of chemicals, like disinfectants and cleaning products, which often contain biocidal active substances that may decrease the barrier function of the skin, especially after repeated exposure. These biocidal products, therefore, may present a safety risk that is not covered by the current risk assessment practice since absorption data are usually obtained by single exposure experiments. Consequently, it was decided to investigate the importance of this issue for biocide safety evaluation. As the literature search revealed that hardly any data on absorption upon repeated dermal exposure to biocides are available, it was concluded that data need to be generated by testing.

    To cover the entire range of biocidal products in such testing, a representative series of biocidal substances should be tested, making in vitro testing of dermal absorption the preferred choice over in vivo testing. Based on an inventory made, it appeared that the 16 product types represented among the biocidal products authorised in the Netherlands could be clustered into 6 more or less homogeneous categories based on similarity in active substances. This result could facilitate experimental testing by providing a basis for selection of a limited number of representative compounds to be evaluated.

    I

    n chapter 4 of this thesis, the importance of the effect of repeated dermal exposure on skin permeability for biocide safety evaluation was investigated, using a selection of nine representative biocides from the inventory made in chapter 3. The in vitro dermal penetration of tritiated water and [14C]propoxur was chosen as a measure of the permeability and integrity of human abdominal skin after single and repeated exposure. The results indicated that single and repeated exposure to specific biocidal products (e.g. the quaternary ammonium chlorides DDAC and ADBAC) may significantly increase skin permeability, especially when the compounds are applied at high concentrations, while a substance like formaldehyde may reduce skin permeability under specific conditions.

    I

    n chapter 5 of this thesis, the in vitro dermal absorption kinetics of the quaternary ammonium compound didecyldimethylammonium chloride (DDAC) during single and repeated exposure was studied in more detail. In addition, the influence of biocidal formulations on the absorption of DDAC was investigated, because it was expected that formulation characteristics may be another factor influencing its dermal absorption. The analysis of biocidal products on the Dutch market, reported in chapter 3, indicated that DDAC is often used in combination with other active ingredients. DDAC was most frequently combined with formaldehyde, glutaraldehyde and/or alkyldimethylbenzyl­ammo­nium chloride (ADBAC). Consequently, commercial formulations containing one or more of these additional active ingredients were selected, in addition to one formulation containing only DDAC as an active ingredient. The selected commercial formulations tended to reduce skin penetration of DDAC. This was most pronounced with the formulation containing the highest concentration of formaldehyde (196 mg/mL) and glutaraldehyde (106 mg/mL), which reduced the flux of DDAC across the skin by 95%. The reduction caused by the only tested formulation containing no other active ingredients than DDAC, and thus incorporating no aldehydes, was smallest, and did not reach statistical significance.

    I

    n chapter 6 of this thesis, a simple in silico model to predict finite dose dermal absorption from infinite dose data (kp and lag time) and the stratum corneum/water partition coefficient (KSC,W) was developed. This model was tentatively called Dermal Absorption Model for Extrapolation (DAME). As dermal exposure may occur under a large variety of conditions leading to quite different rates of absorption, such a predictive model using simple experimental or physicochemical inputs provides a cost-effective means to estimate dermal absorption under different conditions.

    To evaluate the DAME, a series of in vitro dermal absorption experiments was performed under both infinite and finite dose conditions using a variety of different substances. The kp’s and lag times determined in the infinite dose experiments were entered into DAME to predict relative dermal absorption value under finite dose conditions. For six substances, the predicted relative dermal absorption under finite dose conditions was not statistically different from the measured value. For all other substances, measured absorption was overpredicted by DAME, but most of the overpredicted values were still lower than 100%, the European default absorption value for the tested compounds.

    In conclusion, our finite dose prediction model (DAME) provides a useful and cost-effective estimate of in vitro dermal absorption, to be used in risk assessment for non-volatile substances dissolved in water at non-irritating concentrations.

    I

    n chapter 7 of this thesis, the results of the research reported in chapters 2 to 6 were put into perspective, the pitfalls and promises emanating from them discussed and general conclusions drawn. The possible influence of vehicles on absorption and the possible impact of irritative or corrosive vehicles or chemicals on the skin barrier have been demonstrated in this thesis. An in silico predictive model tentatively called DAME was developed, which enables the user to evaluate a variety of dermal exposure scenarios with limited experimental data (kp and lag time) and easy to obtain physicochemical properties (MW and log KOW). The predictions of our experiments reported in chapter 6 were compared to those of the Finite Dose Skin Permeation (FDSP) model published on the internet by the US Centers for Disease Control and Prevention (CDC). DAME outperformed FDSP (R2 of the correlation predicted/measured potential absorption 0.64 and 0.12, respectively). At present, the applicability domain of DAME is limited to non-volatile substances dissolved in aqueous solvents. However, in future the model will be adapted to include volatile substances as well.

    Altogether, it is concluded that dermal exposure can be an important factor in risks posed by chemicals and should be taken into account in risk assessment. The methods to actually do this are still open for further improvement to better account for the various factors influencing skin penetration and to develop adequate combinations of in vitro and in silico models that can accurately predict human dermal absorption.

    Oligosaccharides in Urine, Blood, and Feces of Piglets Fed Milk Replacer Containing Galacto-oligosaccharides
    Difilippo, Elisabetta ; Bettonvil, Monique ; Willems, Rianne ; Braber, Saskia ; Fink-Gremmels, Johanna ; Jeurink, Prescilla V. ; Schoterman, Margriet H.C. ; Gruppen, Harry ; Schols, Henk A. - \ 2015
    Journal of Agricultural and Food Chemistry 63 (2015)50. - ISSN 0021-8561 - p. 10862 - 10872.
    absorption - capillary electrophoresis - creatinine - fermentation - GOS - intestine - liquid chromatography - mass spectrometry - pig - prebiotics

    Human milk oligosaccharides (HMOs) are absorbed into the blood (about 1% of the HMO intake) and subsequently excreted in urine, where they may protect the infant from pathogen infection. As dietary galacto-oligosaccharides (GOS) have partial structural similarities with HMOs, this study investigated the presence of GOS and oligosaccharides originating from milk replacer in blood serum, urine, and cecal and fecal samples of piglets, as a model for human infants. Using liquid chromatography-mass spectrometry and capillary electrophoresis with fluorescence detection, oligosaccharides originating from piglet diet including 3′-sialyllactose and specific GOS ranging from degree of polymerization 3 to 6 were detected in blood serum and in urine of piglets. In blood serum, GOS levels ranged from 16 to 23 μg/mL, representing about 0.1% of the GOS daily intake. In urine, approximately 0.85 g of GOS/g of creatinine was found. Cecum digesta and feces contained low amounts of oligosaccharides, suggesting an extensive GOS intestinal fermentation in piglets.

    Interacties tussen ijzerchelaten en andere spoorelementen vaak onderschat : analysecijfers tonen niet altijd wat beschikbaar is voor plant
    Staalduinen, J. van; Voogt, W. - \ 2015
    Onder Glas 12 (2015)5. - p. 10 - 11.
    glastuinbouw - voedingsstoffen - bemesting - ijzerhoudende meststoffen - plantenvoeding - ijzerabsorptie - chelaten - meststoffen met sporenelementen - absorptie - zuurgraad - substraten - recirculatiesystemen - irrigatiewater - greenhouse horticulture - nutrients - fertilizer application - iron fertilizers - plant nutrition - iron absorption - chelates - trace element fertilizers - absorption - acidity - substrates - recirculating systems - irrigation water
    IJzer is onder normale wortelcondities vaak moeilijk opneembaar voor planten. Dat geldt ook en misschien wel juist voor substraatteelten. IJzerchelaten – organische moleculen die ijzerionen adsorberen en afstaan aan of in plantenwortels – bieden uitkomst. Bij de keuze van het juiste chelaat dient men niet alleen oog te hebben voor de pH van de voedingsoplossing of in de mat. Zij kunnen ook verbindingen aangaan met andere spoorelementen, waardoor drainwateranalyse soms een vertekend beeld geeft van wat er werkelijk beschikbaar is.
    Bioavailability and biodistribution of differently charged polystyrene nanoparticles upon oral exposure in rats
    Walczak, A.P. ; Hendriksen, P.J.M. ; Woutersen, R.A. ; Zande, M. van der; Undas, A.K. ; Helsdingen, J.R. ; Berg, J.H.J. van den; Rietjens, I.M.C.M. ; Bouwmeester, H. - \ 2015
    Journal of Nanoparticle Research : an Interdisciplinary Forum for Nanoscale Science and Technology 17 (2015). - ISSN 1388-0764 - 13 p.
    zinc-oxide nanoparticles - titanium-dioxide nanoparticles - tissue distribution - silver nanoparticles - particle-size - absorption - food - translocation - microspheres - elimination
    The likelihood of oral exposure to nanoparticles (NPs) is increasing, and it is necessary to evaluate the oral bioavailability of NPs. In vitro approaches could help reducing animal studies, but validation against in vivo studies is essential. Previously, we assessed the translocation of 50 nm polystyrene NPs of different charges (neutral, positive and negative) using a Caco-2/HT29-MTX in vitro intestinal translocation model. The NPs translocated in a surface charge-dependent manner. The present study aimed to validate this in vitro intestinal model by an in vivo study. For this, rats were orally exposed to a single dose of these polystyrene NPs and the uptake in organs was determined. A negatively charged NP was taken up more than other NPs, with the highest amounts in kidney (37.4 µg/g tissue), heart (52.8 µg/g tissue), stomach wall (98.3 µg/g tissue) and small intestinal wall (94.4 µg/g tissue). This partly confirms our in vitro findings, where the same NPs translocated to the highest extent. The estimated bioavailability of different types of NPs ranged from 0.2 to 1.7 % in vivo, which was much lower than in vitro (1.6–12.3 %). Therefore, the integrated in vitro model cannot be used for a direct prediction of the bioavailability of orally administered NPs. However, the model can be used for prioritizing NPs before further in vivo testing for risk assessment.
    In vitro selenium accessibility in pet foods is affected by diet composition and type
    Zelst, M. van; Hesta, M. ; Alexander, L.G. ; Gray, K. ; Bosch, G. ; Hendriks, W.H. ; Laing, G. Du; Meulenaer, B. de; Goethals, K. ; Janssens, G. - \ 2015
    The British journal of nutrition 113 (2015)12. - ISSN 0007-1145 - p. 1888 - 1894.
    nutrient digestion - organic selenium - bioavailability - absorption - dog - bioaccessibility - selenomethionine - metabolism - prediction - fiber
    Se bioavailability in commercial pet foods has been shown to be highly variable. The aim of the present study was to identify dietary factors associated with in vitro accessibility of Se (Se Aiv) in pet foods. Se Aiv is defined as the percentage of Se from the diet that is potentially available for absorption after in vitro digestion. Sixty-two diets (dog, n 52; cat, n 10) were in vitro enzymatically digested: fifty-four of them were commercially available (kibble, n 20; pellet, n 8; canned, n 17; raw meat, n 6; steamed meat, n 3) and eight were unprocessed (kibble, n 4; canned, n 4) from the same batch as the corresponding processed diets. The present investigation examined if Se Aiv was affected by diet type, dietary protein, methionine, cysteine, lysine and Se content, DM, organic matter and crude protein (CP) digestibility. Se Aiv differed significantly among diet types (P<0·001). Canned and steamed meat diets had a lower Se Aiv than pelleted and raw meat diets. Se Aiv correlated positively with CP digestibility in extruded diets (kibbles, n 19; r 0·540, P =0·017) and negatively in canned diets (n 16; r - 0·611, P =0·012). Moreover, the canning process (n 4) decreased Se Aiv (P =0·001), whereas extrusion (n 4) revealed no effect on Se Aiv (P =0·297). These differences in Se Aiv between diet types warrant quantification of diet type effects on in vivo Se bioavailability.
    Fat coating of Ca butyrate results in extended butyrate release in the gastrointestinal tract of broilers
    Borne, J.J.G.C. van den; Heetkamp, M.J.W. ; Buyse, J. ; Niewold, T.A. - \ 2015
    Livestock Science 175 (2015). - ISSN 1871-1413 - p. 96 - 100.
    acid breath test - c-13-octanoic acid - chickens - absorption - passage
    Based on its described beneficial effects on small and large intestinal epithelium, butyrate can be a very good alternative to antimicrobial growth promoters. Effective dietary application requires coating because the majority of uncoated butyrate is purportedly absorbed before reaching the proximal small intestine. Several studies using different protocols reported varying stomach passage times in chickens. In the present study, we compared feeding uncoated vs. fat coated [1-13C] labeled Ca butyrate, and compared the effect of butyrate coating with [1-13C] labeled octanoic acid which is an established indicator of stomach passage. By monitoring 13CO2 expiration continuously, we show that the majority (about 80%) of uncoated Ca butyrate is oxidized proximally of the small intestine, and that base line levels were reached after 6 h. Fat coating of Ca butyrate resulted in reduced proximal oxidation (from about 80% to about 45%), and in an extended release pattern of 13CO2 from butyrate similar to that of octanoic acid, and that the return to base line levels was extended to 12 h. This indicated that fat coating of butyrate results in absorption along the entire intestinal tract in broilers, offering an explanation for the described beneficial effects as a growth promoter.
    Factors contributing to the variation in feline urinary oxalate excretion
    Dijcker, J.C. ; Hagen-Plantinga, E.A. ; Everts, H. ; Queau, Y. ; Biourge, V.C. ; Hendriks, W.H. - \ 2014
    Journal of Animal Science 92 (2014)3. - ISSN 0021-8812 - p. 1029 - 1036.
    glycolate excretion - dietary-protein - ascorbic-acid - calcium - cats - hydroxyproline - vitamin-b-6 - fructose - requirement - absorption
    This study aimed to identify factors (season, animal, and diet) contributing to the variation in urinary oxalate (Uox) excretion rate, Uox concentration, and urine volume in healthy adult cats. A data set (1,940 observations) containing information on Uox excretion rate of 65 cats fed 252 diets (i.e., each diet was fed to a group of 6 to 8 cats), with known dietary oxalate concentrations, collected over a 6 yr period at a feline nutrition facility, were retrospectively analyzed. Data related to season, animal (i.e., age, gender, body weight, and breed), and diet (i.e., nutrient content) characteristics were subjected to stepwise multivariate regression analysis to identify factors significantly correlated to Uox excretion rate (µmol/(kg BW0.67·d)) and concentration (mmol/L) as well as urine volume (mL/(kg BW0.67·d)). Independent factors significantly (P <0.05) associated with lower Uox concentration (mmol/L) included greater ash, Ca, and Na intake and lower nitrogen-free extract, total dietary fiber, P, and oxalate intake, and a body weight
    A higher proportion of Iron-Rich leafy vegatables in a typical burkinabe maize meal does not increase the amount of iron absorbed in young women
    Cercamondi, C.I. ; Icard-Verniere, C. ; Egli, I. ; Vernay, M. ; Hama, F. ; Brouwer, I.D. - \ 2014
    The Journal of Nutrition 144 (2014)9. - ISSN 0022-3166 - p. 1394 - 1400.
    phenolic-compounds - stable-isotope - pearl-millet - fortification iron - ascorbic-acid - phytic acid - in-field - absorption - foods - sorghum
    Food-to-food fortification can be a promising approach to improve the low dietary iron intake and bioavailability from monotonous diets based on a small number of staple plant foods. In Burkina Faso, the common diet consists of a thick, cereal-based paste consumed with sauces composed of mainly green leaves, such as amaranth and jute leaves. Increasing the quantity of leaves in the sauces substantially increases their iron concentration. To evaluate whether increasing the quantity of leaves in sauces would provide additional bioavailable iron, an iron absorption study in 18 young women was conducted in Zurich, Switzerland. Burkinabe composite test meals consisting of the maize paste tô accompanied by an iron-improved amaranth sauce, an iron-improved jute sauce, or a traditional amaranth sauce were provided as multiple meals twice a day for 2 consecutive days. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. Mean fractional iron absorption from maize paste consumed with an iron-improved amaranth sauce (4.9%) did not differ from the same meal consumed with an iron-improved jute sauce (4.9%; P = 0.9), resulting in a similar quantity of total iron absorbed (679 vs. 578 µg; P = 0.3). Mean fractional iron absorption from maize paste accompanied by a traditional amaranth sauce (7.4%) was significantly higher than that from the other 2 meal types (P <0.05), but the quantity of total iron absorbed was similar (591 µg; P = 0.4 and 0.7, respectively). A food-to-food fortification approach based on an increase in leafy vegetables does not provide additional bioavailable iron, presumably due to the high phenolic compound concentration of the leaves tested. Alternative measures, such as adding iron absorption enhancers to the sauces, need to be investigated to improve iron nutrition from Burkinabe maize meals.
    Food matrix effects on bioaccessibility of B-Carotene can be measured in a vitro gastrointestinal model
    Loo-Bouwman, C.A. van; Naber, T.H.J. ; Minekus, M. ; Hulshof, P.J.M. ; Schaafsma, G. - \ 2014
    Journal of Agricultural and Food Chemistry 62 (2014)4. - ISSN 0021-8561 - p. 950 - 955.
    green leafy vegetables - digestion method - pro-vitamin - folic-acid - accessibility - serum - bioavailability - absorption - retinol - cassava
    Since the food matrix determines ß-carotene availability for intestinal absorption, food matrix effects on the bioaccessibility of ß-carotene from two diets were investigated in vitro and compared with in vivo data. The “mixed diet” consisted of ß-carotene-rich vegetables, and the “oil diet” contained ß-carotene-low vegetables with supplemental ß-carotene. The application of extrinsically labeled ß-carotene was also investigated. The bioaccessibility of ß-carotene was 28 µg/100 µg ß-carotene from the mixed diet and 53 µg/100 µg ß-carotene from the oil diet. This ratio of 1.9:1 was consistent with in vivo data, where the apparent absorption was 1.9-fold higher in the oil diet than in the mixed diet. The labeled ß-carotene was not equally distributed over time. In conclusion, the food matrix effects on bioaccessibility of ß-carotene could be measured using an in vitro model and were consistent with in vivo data. The application of extrinsically labeled ß-carotene was not confirmed.
    A physiologically based kinetic (PBK) model describing plasma concentrations of quercetin and its metabolites in rats
    Boonpawa, R. ; Spenkelink, A. ; Rietjens, I. ; Punt, A. - \ 2014
    Biochemical Pharmacology 89 (2014)2. - ISSN 0006-2952 - p. 287 - 299.
    flavonoid-mediated inhibition - blood partition-coefficients - oral bioavailability - biological-activity - biliary-excretion - intestinal uptake - glucuronidation - humans - absorption - tissues
    Biological activities of flavonoids in vivo are ultimately dependent on the systemic bioavailability of the aglycones as well as their metabolites. In the present study, a physiologically based kinetic (PBK) model was developed to predict plasma concentrations of the flavonoid quercetin and its metabolites and to tentatively identify the regiospecificity of the major circulating metabolites. The model was developed based on in vitro metabolic parameters and by fitting kinetic parameters to literature available in vivo data. Both exposure to quercetin aglycone and to quercetin-4'-O-glucoside, for which in vivo data were available, were simulated. The predicted plasma concentrations of different metabolites adequately matched literature reported plasma concentrations of these metabolites in rats exposed to 4'-O-glucoside. The bioavailability of aglycone was predicted to be very low ranging from 0.004%-0.1% at different oral doses of quercetin or quercetin-4'-O-glucoside. Glucuronidation was a crucial pathway that limited the bioavailability of the aglycone, with 95–99% of the dose being converted to monoglucuronides within 1.5–2.5 h at different dose levels ranging from 0.1 to 50 mg/kg bw quercetin or quercetin-4'-O-glucoside. The fast metabolic conversion to monoglucuronides allowed these metabolites to further conjugate to di- and tri-conjugates. The regiospecificity of major circulating metabolites was observed to be dose-dependent. As we still lack in vivo kinetic data for many flavonoids, the developed model has a great potential to be used as a platform to build PBK models for other flavonoids as well as to predict the kinetics of flavonoids in humans.
    Predicting individual responses to pravastatin using a physiologically based kinetic model for plasma cholesterol levels
    Pas, N.C.A. van de; Rullmann, J. ; Woutersen, R.A. ; Ommen, B. van; Rietjens, I. ; Graaf, A.A. de - \ 2014
    Journal of Pharmacokinetics and Pharmacodynamics 41 (2014)4. - ISSN 1567-567X - p. 351 - 362.
    coa reductase inhibitors - statin therapy - lowering-therapy - ldl cholesterol - hepg2 cells - atorvastatin - simvastatin - absorption - metabolism - trial
    We used a previously developed physiologically based kinetic (PBK) model to analyze the effect of individual variations in metabolism and transport of cholesterol on pravastatin response. The PBK model is based on kinetic expressions for 21 reactions that interconnect eight different body cholesterol pools including plasma HDL and non-HDL cholesterol. A pravastatin pharmacokinetic model was constructed and the simulated hepatic pravastatin concentration was used to modulate the reaction rate constant of hepatic free cholesterol synthesis in the PBK model. The integrated model was then used to predict plasma cholesterol concentrations as a function of pravastatin dose. Predicted versus observed values at 40 mg/d pravastatin were 15 versus 22 % reduction of total plasma cholesterol, and 10 versus 5.6 % increase of HDL cholesterol. A population of 7,609 virtual subjects was generated using a Monte Carlo approach, and the response to a 40 mg/d pravastatin dose was simulated for each subject. Linear regression analysis of the pravastatin response in this virtual population showed that hepatic and peripheral cholesterol synthesis had the largest regression coefficients for the non-HDL-C response. However, the modeling also showed that these processes alone did not suffice to predict non-HDL-C response to pravastatin, contradicting the hypothesis that people with high cholesterol synthesis rates are good statin responders. In conclusion, we have developed a PBK model that is able to accurately describe the effect of pravastatin treatment on plasma cholesterol concentrations and can be used to provide insight in the mechanisms behind individual variation in statin response.
    The effect of fibers on coagulation of casein-based enteral nutrition in an artificial gastric digestion model
    Luttikhold, J. ; Norren, K. van; Minor, M. ; Buijs, N. ; Braak, C.C.M. van den; Ludwig, T. ; Abrahamse, E. ; Rijna, H. ; Leeuwen, P.A.M. - \ 2014
    Food & Function 5 (2014). - ISSN 2042-6496 - p. 1866 - 1871.
    critically-ill patients - thermodynamic incompatibility - intestinal-obstruction - in-vitro - motility - proteins - absorption - guidelines - mixtures - feedings
    A serious complication seen in critically ill patients is the solidification of enteral nutrition causing gastrointestinal obstruction. It has been suggested that enteral nutrition enriched with insoluble fibers may increase the risk of this complication. Therefore, we investigate the effect of soluble and insoluble dietary fibers on the coagulation of a casein-based enteral nutrition in an artificial gastric digestion model. A 100% casein-based enteral nutrition was enriched with increasing concentrations of soluble fibers (acacia fiber, oligofructose and inulin) and insoluble fibers (soy polysaccharide, resistant starch and alpha cellulose). After digestion in an artificial gastric model, the chyme was poured over sequentially placed sieves, separating the coagulate into size fractions of larger than 2 mm, between 1 and 2 mm, and between 0.25 and 1 mm. Of these fractions we measured wet weight, dry weight and protein content. A significant effect on the fraction larger than 2 mm was considered to be clinically relevant. Addition of high concentrations soy polysaccharide and resistant starch to a casein-based enteral nutrition, did not alter the wet weight, whereas dry weight and protein content of the coagulate was significantly reduced. When high concentrations of soy polysaccharide and resistant starch are added to a 100% casein-based enteral nutrition, the coagulate consist of more water and less proteins, which may lead to an increased protein digestion and absorption in a clinical setting. The suggestion that insoluble fibers increase the risk of gastrointestinal obstruction in critically ill patients is not supported by these data.
    The effect of steam pelleting of a dry dog food on the Maillard reaction
    Rooijen, C. van; Bosch, G. ; Wierenga, P.A. ; Hendriks, W.H. ; Poel, A.F.B. van der - \ 2014
    Animal Feed Science and Technology 198 (2014). - ISSN 0377-8401 - p. 238 - 247.
    glycation end-products - physical quality - nutritive-value - animal feed - lysine - diet - digestibility - absorption - components - proteins
    During processing of pet foods, the Maillard reaction (MR) can occur, which reduces the bioavailability of essential amino acids like lysine and results in the formation of advanced Maillard reaction products (MRPs). This study examined the effect of conditioning temperature (65 and 90 °C) and die hole length (ø 5 × 45, 65, and 80 mm) during pelleting processing of a standard dry dog food on selected indicators of the MR (total lysine, reactive lysine, fructoselysine, ¿-N-carboxymethyllysine, (5-hydroxymethyl)-2-furfural, lysinoalanine), browning development and CIE-Lab color. Steam pelleting variables did not cause a significant loss of lysine or change in color and absorbance values. Analyzing the unprocessed ingredient mix suggests that the choice of the ingredients used in the ingredient mix, rather than the pelleting process applied, is responsible for the RL/TL ratio observed in the dry standard dog food used in this study. MRP content increased during steam pelleting (fructoselysine: 366.2 to 538.8 mg/kg DM; ¿-N-carboxymethyllysine: 12.6 to 14.8 mg/kg DM; lysinoalanine: 5.7 to 7.7 mg/kg DM; P <0.05). Increasing conditioning temperature from 65 to 90 °C increased fructoselysine (475.9 to 601.6 mg/kg DM; P <0.01) and ¿-N-carboxymethyllysine (14.3 to 15.1 mg/kg DM; P = 0.003). An increased die hole length of 80 mm decreased fructoselysine content compared to 45 and 65 mm (461.3 vs. 573.3 and 581.6 mg/kg DM; P <0.01) but increased lysinoalanine content (8.8 vs. 7.4 and 6.8 mg/kg DM; P = 0.002). Analyzing total and reactive lysine and absorbance values are not accurate enough to predict the MR and formation of MRPs during processing.
    Electroactive behavior assessment of poly(acrylic acid)-graphene oxide composite hydrogel in the detection of cadmium
    Bejarano-Jimenez, A. ; Escobar-Barrios, V.A. ; Kleijn, J.M. ; Oritz-Ledon, C.A. ; Chazaro-Ruiz, L.F. - \ 2014
    Journal of Applied Polymer Science 131 (2014)19. - ISSN 0021-8995 - 10 p.
    carbon-paste electrodes - swelling properties - metal-ions - acid) - polymerization - gels - complexation - absorption - water - ph
    Super absorbent polymers of acrylic acid-graphene oxide (PAA-GO) were synthesized with different percentage of chemical neutralization (0, 10, and 20%) of the acrylic acid monomer before its polymerization. The influence of their swelling and adsorption/desorption capacity of cadmium ions in aqueous solutions were studied and revealed that the GO enables greater mechanical stability in the materials. The PAA hydrogels, with the same degrees of neutralization, were also prepared without GO to compare with the composites. Additionally, carbon paste electrodes (CPE) modified with the composites PAA-GO were used to asses and compare their adsorption properties with cadmium(II). The anodic stripping voltammetry (ASV) peak, in the differential pulse voltammetry mode, for cadmium oxidation was found to be influenced by the presence of GO into the polymer, and also by their percentage of neutralization. The accumulation of cadmium(II) on the surface of the modified CPEs was performed under open-circuit conditions taking an account the preconcentration time of the metal cation. The presence of GO enhances the electrical signal of the electrodes in short times of immersion in cadmium(II) solutions. This property contributed to get linear responses of the CPEs modified with the composites, which were influenced by their degrees of neutralization. The PAA-GO 10N electrode with 10% of neutralization combined the influence of GO and the degree of neutralization in the same matrix, and also showed good performance in terms of its mechanical stability, it was chosen for preliminary studies on the selectivity of the electrode toward Zn(II) and Cu(II).
    Peripartal calcium homoeostasis of multiparous dairy cows fed rumen-protected rice bran or a lowered dietary cation/anion balance diet before calving
    Martin-Tereso, J. ; Wijlen, H. ter; Laar, H. van; Verstegen, M.W.A. - \ 2014
    Journal of Animal Physiology and Animal Nutrition 98 (2014)4. - ISSN 0931-2439 - p. 775 - 784.
    anion difference - milk fever - dry period - hypocalcemia - metaanalysis - absorption - disorders - nutrition - health - cattle
    Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close-up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen-protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen-protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen-protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post-calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen-protected rice bran may be a suitable feed to reduce hypocalcaemia post-partum and can be included in pre-calving compound feeds representing a palatable alternative to anionic salts.
    Efficacy of dimethylglycine as a feed additive to improve broiler production
    Kalmar, I.D. ; Verstegen, M.W.A. ; Vanrompay, D. ; Maenner, K. ; Zentek, J. ; Iben, C. ; Leitgeb, R. ; Schiavone, A. ; Prola, L. ; Janssens, G. - \ 2014
    Livestock Science 164 (2014). - ISSN 1871-1413 - p. 81 - 86.
    amino-acids - n,n-dimethylglycine - supplementation - digestibility - performance - absorption - choline - betaine - diet
    Dimethylglycine (DMG) is a naturally occurring glycine derivative, which is useful as additive to broiler diets as it improves nutrient digestibility and reduces the development of broiler ascites syndrome. This study evaluated the efficacy of dietary DMG to enhance performance of broiler chickens. Three trials were conducted to evaluate the effect of dietary supplementation with 1 g Na DMG/kg on growth performance and carcass characteristics. In Trial 1, the effect of sex was also assessed in a 2×2 factorial arrangement of treatments. In Trials 1 (Germany), 2 (Austria), and 3 (Italy), each treatment consisted of 6, 12, and 11 replicate pens with 20, 15, and 16 one-day-old broiler chickens per pen, respectively. Dietary DMG supplementation resulted in improved feed conversion ratio (FCR) in the starter phase by 8.8% (P=0.004), 6.4% (P=0.001), and 4.8% (P=0.006) compared with the control diet in Trials 1, 2, and 3, respectively. The overall FCR improved in broiler chickens fed the diets supplemented with DMG by 3.8% and 4.1% in Trials 1 (P=0.007) and 3 (P=0.006), respectively. In addition, final body weight increased by 5.5% (P=0.001) in Trial 2 and production value improved by 6.8% (P=0.015) in Trial 1 by dietary DMG supplementation. Mortality in all trials was similar between dietary treatments. In all 3 trials, cold carcass weight and total meat yield were as well similar between broiler chickens fed the control and DMG diets. In Trial 1, dietary DMG had no effect on breast meat yield in male broiler chickens, but it increased breast meat yield in female broiler chickens (diet×sex, P=0.004). Organoleptic quality of roasted breast meat assessed only in Trial 2 was not affected by dietary treatments. In conclusion, dietary supplementation of DMG at 1 g Na DMG/kg can considerably improve s production performance in broiler chickens.
    Conversion of major soy isoflavone glucosides and aglycones in in vitro intestinal models
    Islam, M.A. ; Punt, A. ; Spenkelink, A. ; Murk, A.J. ; Leeuwen, F.X.R. ; Rietjens, I. - \ 2014
    Molecular Nutrition & Food Research 58 (2014)3. - ISSN 1613-4125 - p. 503 - 515.
    rat small-intestine - lactase-phlorhizin hydrolase - caco-2 cell monolayers - beta-glucosidase - 1st-pass metabolism - phyto-estrogens - human plasma - absorption - bioavailability - glycosides
    ScopeThis study compares conversion of three major soy isoflavone glucosides and their aglycones in a series of in vitro intestinal models. Methods and resultsIn an in vitro human digestion model isoflavone glucosides were not deconjugated, whereas studies in a Caco-2 transwell model confirmed that deconjugation is essential to facilitate transport across the intestinal barrier. Deconjugation was shown upon incubation of the isoflavone glucosides with rat as well as human intestinal S9. In incubations with rat intestinal S9 lactase phlorizin hydrolase, glucocerebrosidase, and cytosolic broad-specific -glucosidase all contribute significantly to deconjugation, whereas in incubations with human intestinal S9 deconjugation appeared to occur mainly through the activity of broad-specific -glucosidase. Species differences in glucuronidation and sulfation were limited and generally within an order of magnitude with 7-O-glucuronides being the major metabolites for all three isoflavone aglycones and the glucuronidation during first pass metabolism being more efficient in rats than in humans. Comparison of the catalytic efficiencies reveals that deconjugation is less efficient than conjugation confirming that aglycones are unlikely to enter the systemic circulation. ConclusionAltogether, the data point at possible differences in the characteristics for intestinal conversion of the major soy isoflavones between rat and human, especially with respect to their deconjugation.
    Quantum Chemical Studies on Solvents for Post-Combustion Carbon Dioxide Capture: Calculation of pKa and Carbamate Stability of Disubtituted Piperazines
    Gangarapu, S. ; Wierda, G.J. ; Marcelis, A.T.M. ; Zuilhof, H. - \ 2014
    ChemPhysChem 15 (2014). - ISSN 1439-4235 - p. 1880 - 1886.
    sterically hindered amines - co2 capture - aqueous piperazine - pilot-plant - absorption - performance - technology - basicities - parameters - constants
    Piperazine is a widely studied solvent for post-combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of CH3, CH2F, CH2OH, CH2NH2, COCH3, and CN groups of 2,5-disubstituted piperazines on the pKa and carbamate stability towards hydrolysis are investigated by quantum chemical methods. For the calculations, B3LYP, M11L, and spin-component-scaled MP2 (SCS-MP2) methods are used and coupled with the SMD solvation model. The experimental pKa values of piperazine, 2-methylpiperazine, and 2,5-dimethylpiperazine agree well with the calculated values. The present study indicates that substitution of CH3, CH2NH2, and CH2OH groups on the 2- and 5-positions of piperazine has a positive impact on the CO2 absorption capacity by reducing the carbamate stability towards hydrolysis. Furthermore, their higher boiling points, relative to piperazine itself, will lead to a reduction of volatility-related losses.
    Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems
    Dykstra, J.E. ; Biesheuvel, P.M. ; Bruning, H. ; Heijne, A. ter - \ 2014
    Physical Review. E, Statistical nonlinear, and soft matter physics 90 (2014). - ISSN 1539-3755 - 10 p.
    microbial electrolysis cell - hydrogen-production - fuel-cells - quantitative approach - mathematical-model - ammonium recovery - chemical-reaction - inorganic carbon - urine - absorption
    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since most of the ionic species can undergo acid-base reactions, ion transport is combined in our model with infinitely fast ion acid-base equilibrations. The model describes the current-induced ammonia evaporation and recovery at the cathode side of a bioelectrochemical system that runs on an organic stream containing ammonium ions. We identify that the rate of ammonia evaporation depends not only on the current but also on the flow rate of gas in the cathode chamber, the diffusion of ammonia from the cathode back into the anode chamber, through the ion exchange membrane placed in between, and the membrane charge density.
    In Silico Prediction and Automatic LC–MSn Annotation of Green Tea Metabolites in Urine
    Ridder, L.O. ; Hooft, J.J.J. van der; Verhoeven, S. ; Vos, R.C.H. de; Vervoort, J.J.M. ; Bino, R.J. - \ 2014
    Analytical Chemistry 86 (2014)10. - ISSN 0003-2700 - p. 4767 - 4774.
    human fecal microbiota - mass-spectrometry - structural elucidation - human plasma - phenolic-compounds - spectral trees - polyphenols - identification - absorption - metabolomics
    The colonic breakdown and human biotransformation of small molecules present in food can give rise to a large variety of potentially bioactive metabolites in the human body. However, the absence of reference data for many of these components limits their identification in complex biological samples, such as plasma and urine. We present an in silico workflow for automatic chemical annotation of metabolite profiling data from liquid chromatography coupled with multistage accurate mass spectrometry (LC-MSn), which we used to systematically screen for the presence of tea-derived metabolites in human urine samples after green tea consumption. Reaction rules for intestinal degradation and human biotransformation were systematically applied to chemical structures of 75 green tea components, resulting in a virtual library of 27¿245 potential metabolites. All matching precursor ions in the urine LC–MSn data sets, as well as the corresponding fragment ions, were automatically annotated by in silico generated (sub)structures. The results were evaluated based on 74 previously identified urinary metabolites and lead to the putative identification of 26 additional green tea-derived metabolites. A total of 77% of all annotated metabolites were not present in the Pubchem database, demonstrating the benefit of in silico metabolite prediction for the automatic annotation of yet unknown metabolites in LC–MSn data from nutritional metabolite profiling experiments.
    Sub-chronic toxicity study in rats orally exposed to nanostructured silica
    Zande, M. van der; Vandebriel, R.J. ; Groot, M.J. ; Kramer, E.H.M. ; Herrera Riviera, Z.E. ; Rasmussen, K. ; Ossenkoppele, J.S. ; Tromp, P. ; Gremmer, E.R. ; Peters, R.J.B. ; Hendriksen, P.J. ; Marvin, H.J.P. ; Hoogenboom, L.A.P. ; Peijnenburg, A.A.C.M. ; Bouwmeester, H. - \ 2014
    Particle and Fibre Toxicology 11 (2014). - ISSN 1743-8977
    in-vivo biodistribution - expression profiles - liver fibrosis - nanoparticles - absorption - elimination - injection - foods - acid - size
    Synthetic Amorphous Silica (SAS) is commonly used in food and drugs. Recently, a consumer intake of silica from food was estimated at 9.4 mg/kg bw/day, of which 1.8 mg/kg bw/day was estimated to be in the nano-size range. Food products containing SAS have been shown to contain silica in the nanometer size range (i.e. 5 – 200 nm) up to 43% of the total silica content. Concerns have been raised about the possible adverse effects of chronic exposure to nanostructured silica.
    Compensation in Root Water Uptake Models Combined with Three-Dimensional Root Length Density Distribution
    Heinen, M. - \ 2014
    Vadose Zone Journal 13 (2014)2. - ISSN 1539-1663 - 9 p.
    hydraulic architecture - integrated approach - porous-media - absorption - conductivity - systems - soils
    A three-dimensional root length density distribution function is introduced that made it possible to compare two empirical uptake models with a more mechanistic uptake model. Adding a compensation component to the more empirical model resulted in predictions of root water uptake distributions similar to those predicted by the more complex model. Because root water uptake is a considerable component in the soil water balance, a lot of attention has been paid to defining and applying root water uptake models. These models can be grouped into empirical vs. mechanistic root uptake models. Intermodel comparisons are valuable in understanding the different concepts used. Such a comparison is sometimes difficult because the level of information required by the models is different, for example, information on the root length density distribution. Here a three-dimensional root length density distribution function is introduced that makes it possible to compare two empirical uptake models with a more mechanistic uptake model. Adding a compensation component to the more empirical model results in prediction of root water uptake distributions in the root zone similar to those predicted by the more complex model.
    Minimizing measurement uncertainties of coniferous needle-leaf optical properties, part I: methodological review
    Yanez Rausell, L. ; Schaepman, M.E. ; Clevers, J.G.P.W. ; Malenovsky, Z. - \ 2014
    IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 7 (2014)2. - ISSN 1939-1404 - p. 399 - 405.
    revised measurement methodology - chlorophyll content estimation - radiative-transfer model - reflectance spectra - hyperspectral data - bifacial leaf - boreal forest - leaves - light - absorption
    Optical properties (OPs) of non-flat narrow plant leaves, i.e., coniferous needles, are extensively used by the remote sensing community, in particular for calibration and validation of radiative transfer models at leaf and canopy level. Optical measurements of such small living elements are, however, a technical challenge and only few studies attempted so far to investigate and quantify related measurement errors. In this paper we review current methods and developments measuring optical properties of narrow leaves. We discuss measurement shortcomings and knowledge gaps related to a particular case of non-flat nonbifacial coniferous needle leaves, e.g., needles of Norway spruce (Picea abies (L.) Karst.).
    Optimizing illumination in the greenhouse using a 3D model of tomato and a ray tracer
    Visser, P.H.B. de; Buck-Sorlin, G.H. ; Heijden, G.W.A.M. van der - \ 2014
    Frontiers in Plant Science 5 (2014). - ISSN 1664-462X - 7 p.
    structural plant-model - light interception - cucumber canopies - photosynthesis - simulation - environment - absorption
    Reduction of energy use for assimilation lighting is one of the most urgent goals of current greenhouse horticulture in the Netherlands. In recent years numerous lighting systems have been tested in greenhouses, yet their efficiency has been very difficult to measure in practice. This simulation study evaluated a number of lighting strategies using a 3D light model for natural and artificial light in combination with a 3D model of tomato. The modeling platform GroIMP was used for the simulation study. The crop was represented by 3D virtual plants of tomato with fixed architecture. Detailed data on greenhouse architecture and lamp emission patterns of different light sources were incorporated in the model. A number of illumination strategies were modeled with the calibrated model. Results were compared to the standard configuration. Moreover, adaptation of leaf angles was incorporated for testing their effect on light use efficiency (LUE). A Farquhar photosynthesis model was used to translate the absorbed light for each leaf into a produced amount of carbohydrates. The carbohydrates produced by the crop per unit emitted light from sun or high pressure sodium lamps was the highest for horizontal leaf angles or slightly downward pointing leaves, and was less for more upward leaf orientations. The simulated leaf angles did not affect light absorption from inter-lighting LED modules, but the scenario with LEDs shining slightly upward (20°) increased light absorption and LUE relative to default horizontal beaming LEDs. Furthermore, the model showed that leaf orientation more perpendicular to the string of LEDs increased LED light interception. The combination of a ray tracer and a 3D crop model could compute optimal lighting of leaves by quantification of light fluxes and illustration by rendered lighting patterns. Results indicate that illumination efficiency increases when the lamp light is directed at most to leaves that have a high photosynthetic potential. - See more at: http://journal.frontiersin.org/Journal/10.3389/fpls.2014.00048/abstract#sthash.oZ0vUtYM.dpuf
    Energy from CO2 using capacitive electrodes – Theoretical outline and calculation of open circuit voltage
    Par-Garcia, J.M. ; Schaetzle, O. ; Biesheuvel, P.M. ; Hamelers, H.V.M. - \ 2014
    Journal of Colloid and Interface Science 418 (2014). - ISSN 0021-9797 - p. 200 - 207.
    anion-exchange membranes - porous-electrodes - carbamate formation - aqueous-solution - acid anions - monoethanolamine - equilibrium - absorption - simulation - capture
    Recently, a new technology has been proposed for the utilization of energy from CO2 emissions (Hamelers et al., 2014). The principle consists of controlling the dilution process of CO2–concentrated gas (e.g., exhaust gas) into CO2–dilute gas (e.g., air) thereby extracting a fraction of the released mixing energy. In this paper, we describe the theoretical fundamentals of this technology when using a pair of charge–selective capacitive electrodes. We focus on the behavior of the chemical system consisting of CO2 gas dissolved in water or monoethanolamine solution. The maximum voltage given for the capacitive cell is theoretically calculated, based on the membrane potential. The different aspects that affect this theoretical maximum value are discussed.
    Assessing environmental consequences of using co-products in animal feed
    Zanten, H.H.E. van; Mollenhorst, H. ; Vries, J.W. de; Middelaar, C.E. van; Kernebeek, H.R.J. van; Boer, I.J.M. de - \ 2014
    The International Journal of Life Cycle Assessment 19 (2014)1. - ISSN 0948-3349 - p. 79 - 88.
    bio-energy - digestion - impact - rumen - perspective - absorption - manure - tract - model
    The livestock sector has a major impact on the environment. This environmental impact may be reduced by feeding agricultural co-products (e.g. beet tails) to livestock, as this transforms inedible products for humans into edible products, e.g. pork or beef. Nevertheless, co-products have different applications such as bioenergy production. Based on a framework we developed, we assessed environmental consequences of using co-products in diets of livestock, including the alternative application of that co-product. We performed a consequential life cycle assessment, regarding greenhouse gas emissions (including emissions related to land use change) and land use, for two case studies. Case 1 includes increasing the use of wheat middlings in diets of dairy cattle at the expense of using it in diets of pigs. The decreased use of wheat middlings in diets of pigs was substituted with barley, the marginal product. Case 2 includes increasing the use of beet tails in diets of dairy cattle at the expense of using it to produce bioenergy. During the production of biogas, electricity, heat and digestate (that is used as organic fertilizer) were produced. The decrease of electricity and heat was substituted with fossil fuel, and digestate was substituted with artificial fertilizer. Using wheat middlings in diets of dairy cattle instead of using it in diets of pigs resulted in a reduction of 329 kg CO2 eq per ton wheat middlings and a decrease of 169 m(2) land. Using beet tails in diets of dairy cattle instead of using it as a substrate for anaerobic digestion resulted in a decrease of 239 kg CO2 eq per ton beet tails and a decrease of 154 m(2) land. Emissions regarding land use change contributed significantly in both cases but had a high uncertainty factor, +/- 170 ton CO2 ha(-1). Excluding emissions from land use change resulted in a decrease of 9 kg CO2 eq for case 1 'wheat middlings' and an increase of 50 kg CO2 eq for case 2 'beet tails'. Assessing the use of co-products in the livestock sector is of importance because shifting its application can reduce the environmental impact of the livestock sector. A correct assessment of the environmental consequences of using co-products in animal feed should also include potential changes in impacts outside the livestock sector, such as the impact in the bioenergy sector.
    Novel multi-sugar assay for site-specific gastrointestinal permeability analysis: A randomized controlled crossover trial
    Wijck, K. van; Verlinden, T.J.M. ; Eijk, H.M.H. van; Dekker, J. ; Buurman, W.A. ; Dejong, C.H.C. ; Lenaerts, K. - \ 2013
    Clinical Nutrition 32 (2013)2. - ISSN 0261-5614 - p. 245 - 251.
    nonsteroidal antiinflammatory drugs - intestinal permeability - humans - mannitol - nsaid - indomethacin - absorption - lactulose - rat - enteropathy
    Background & aims: Increased gastrointestinal (GI) permeability is an important hallmark of many conditions, potentially leading to antigen exposure and sepsis. Current permeability tests are hampered by analytical limitations. This study aims to compare the accuracy of our multi-sugar (MS) and the classical dual sugar (DS) test for detection of increased GI permeability. Methods: Ten volunteers received permeability analysis using MS (1 g sucrose, lactulose, sucralose, erythritol, 0.5 g rhamnose in water) or DS (5 g lactulose, 0.5 g rhamnose), after indomethacin or placebo. Blood and urine were analyzed by isocratic LC-MS. Results: MS testing revealed significantly elevated urinary lactulose/rhamnose (L/R) ratios after indomethacin, due to enhanced lactulose excretion (P <.01) and unaltered rhamnose excretion. The DS test showed increased L/R ratios, due to increased lactulose excretion and decreased rhamnose excretion (both P <.05). After indomethacin, plasma L/R increased in both assays (P <.05 and P <.01). Urinary and plasma L/R ratios correlated significantly. Indomethacin increased sucrose excretion and 0-1 h sucrose/rhamnose. Colon permeability was unchanged. Conclusions: Sensitive permeability analysis is feasible in plasma and urine using MS or DS test. In contrast to the DS test, monosaccharide excretion is not decreased by the MS test. In short, the MS test provides accurate, site-specific information on gastroduodenal, small, and large intestinal permeability. Registered at US National Library of Medicine (http://www.clinicaltrials.gov, NCT00943345). (C) 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
    Simulation of the effect of maize porridge fortified with grain amaranth or micronutrient powder containing NaFeEDTA on iron intake and status in Kenyan children
    Macharia-Mutie, C.W. ; Omusundi, A.M. ; Mwai, J.M. ; Mwangi, A.M. ; Brouwer, I.D. - \ 2013
    Public Health Nutrition 16 (2013)9. - ISSN 1368-9800 - p. 1605 - 1613.
    preschool-children - body iron - deficiency - absorption - anemia - women - trial - foods - biofortification - bioavailability
    Objective: Simulating the probable impact of grain amaranth and highly absorbable, low-Fe micronutrient powder (MNP) on Fe status in a potential target population is an essential step in choosing and developing an appropriate actual intervention. Design: We simulated the potential effect of fortifying maize porridge with grain amaranth or MNP on the prevalence of inadequate Fe intake and Fe deficiency using data from two cross-sectional surveys. In the first survey (2008), dietary intake data were collected by two 24 h recalls (n 197). Biochemical data (n 70) were collected in the second survey (2010). A simulation with daily consumption for 80 d of non-fortified maize porridge (60 g of maize flour), amaranth-enriched porridge (80 g of grain amaranth-maize flour, 70: 30 ratio) or maize porridge fortified with MNP (2.5 mg Fe as NaFeEDTA) was done. Setting: Mwingi District, Kenya. Subjects: Pre-school children aged 12-23 months. Results: Prevalence of anaemia, Fe deficiency and Fe-deficiency anaemia was 49%, 46% and 24%, respectively. Consumption of non-fortified, amaranth-enriched and MNP-fortified maize porridge was estimated to provide a median daily Fe intake of 8.6 mg, 17.5 mg and 11.1 mg, respectively. The prevalence of inadequate Fe intake was reduced to 35% in the amaranth-enriched porridge group and 45% in the MNP-fortified porridge group, while ferritin concentration was increased in both (by 1.82 (95% CI 1.42, 2.34) mu g/l and 1.80 (95% CI 1.40, 2.31) mu g/l, respectively; P
    Glucose and calcium ions may modulate the efficiency of bovine B-casomorphin-7 permeability through a monolayer of Caco-2 cells
    Jarmolowska, B. ; Teodorowicz, M. ; Fiedorowicz, E. ; Sienkiewicz-Szlapka, E. ; Matysiewicz, M. ; Kostyra, E. - \ 2013
    Peptides 49 (2013). - ISSN 0196-9781 - p. 59 - 67.
    beta-casomorphin - opioid-peptides - tight junctions - endothelial permeability - intestinal permeability - gene-expression - transport - milk - absorption - iv
    Milk and dairy products provide a lot of valuable nutritive elements. They are also sources of biologically active peptides, including ß-casomorphins that manifest the properties of morphine. An activity of DPPIV seems to be most crucial factor decreasing the efficiency of the ß-casomorphin-7 (BCM7) transport. The increase of BCM7 concentration in blood may intensify symptoms of apparent life threatening events (ALTE), autism, schizophrenia, and allergy. This study aimed at identifying the influence of several selected substances on a transport efficiency of bovine BCM7 through an intestinal monolayer in a Caco-2 cell model system. Applying the ELISA method, the permeability coefficient of BCM7 through the Caco-2 monolayer was calculated. TEER values were used to evaluate the integrity of Caco-2 cell monolayers. An increase of glucose and Ca(2+) concentrations in the culture medium was accompanied by an increase of the BCM7 transport efficiency. The lowest permeability coefficients of BCM7 were observed for the membranes with high electrical resistances. The transport was enhanced in the presence of milk infant formulas, whereas no changes were observed when using µ-opioid receptor antagonist (casoxin-6). The results may be useful in understanding the pathogenesis of inflammation and food allergy in infants.
    Carbamate Stabilities of Sterically Hindered Amines from Quantum Chemical Methods: Relevance ofr CO2 Capture
    Gangarapu, S. ; Marcelis, A.T.M. ; Zuilhof, H. - \ 2013
    ChemPhysChem 14 (2013)17. - ISSN 1439-4235 - p. 3936 - 3943.
    free-energy perturbations - carbon-dioxide - reaction-kinetics - aqueous-solutions - initio methods - absorption - 2-amino-2-methyl-1-propanol - methyldiethanolamine - monoethanolamine - technology
    The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled with SMD and SM8 solvation models. A reduction in carbamate stability leads to an increased CO2 absorption capacity of the amine and a reduction of the energy required for solvent regeneration. Important factors for the reduction of the carbamate stability were an increase in steric hindrance around the nitrogen atom, charge on the N atom and intramolecular hydrogen bond strength. The present study indicates that secondary ethanolamines with sterically hindering groups near the N atom show significant potential as candidates for industrial CO2-capture solvents.
    Comparison of ileal and total tract nutrient digestibility of dry dog foods
    Hendriks, W.H. ; Thomas, G. ; Bosch, G. ; Fahey, G.C. - \ 2013
    Journal of Animal Science 91 (2013)8. - ISSN 0021-8812 - p. 3807 - 3814.
    amino-acid-composition - endogenous nitrogen - reactive lysine - protein - pigs - diets - bioavailability - ingredients - absorption - intestine
    The apparent total tract and ileal digestibility assays to measure AA absorption in commercial canine diets were compared in the present study. Five ileal cannulated dogs were fed 5 commercial dry canine foods selected to contain 19 to 30% CP in a 5 × 5 Latin square design. Ileal and total tract digestibility (apparent and standardized) of DM, OM, CP, crude fat (CF), carbohydrate, and AA (including reactive Lys) were calculated using Cr2O3 as an indigestible marker. Greater apparent total tract digestibility values were found for DM, OM, and CP (P = 0.034) compared with ileal digestibility values; however, CF (P = 0.058) had a greater ileal apparent digestibility. Apparent and standardized CP digestibility values were, respectively, 5.7 and 7.4 percentage units greater when measured over the total digestive tract compared with measurement at the ileum (P = 0.034 and 0.011, respectively). Ileal apparent digestibility for N of AA (P = 0.009) and most AA (P <0.05), except for Met, Ile, Lys, Phe, and Ala, was decreased if measured at the ileum. However, correction for endogenous losses showed only Met digestibility did not differ between measurement sites. Differences between sites in excess of 15 percentage units were recorded for AA. Apparent and standardized ileal reactive Lys digestibility was 3.1 to 15.3 percentage units greater than corresponding total tract digestibility values. For several indispensable AA, the bioavailability estimates currently used by the 2006 NRC and the 2011 Association of American Feed Control Officials to derive allowance estimates for canine adult maintenance were greater than the digestibility values of these AA in the commercial dog foods evaluated. Although the canine large intestine is relatively short, the total tract digestibility assay in dogs can overestimate the digestibility of dietary AA and CP and may not be an accurate method for the measurement of absorption. In this study, bioavailability estimates of AA appeared to be less than those used to derive allowance estimates for commercial dog foods. Further work is required if current recommendations warrant adjustment.
    Investigating the Transport Dynamics of Anthocyanins from Unprocessed Fruit and Processed Fruit Juice from Sour Cherry (Prunus cerasus L.) across Intestinal Epithelial Cells
    Toydemir, G. ; Boyacioglu, D. ; Capanoglu, E. ; Meer, I.M. van der; Tomassen, M.M.M. ; Hall, R.D. ; Mes, J.J. ; Beekwilder, J. - \ 2013
    Journal of Agricultural and Food Chemistry 61 (2013)47. - ISSN 0021-8561 - p. 11434 - 11441.
    red grape juice - protein interactions - cellular uptake - absorption - quercetin - dietary - caco-2 - bioavailability - consumption - glucosides
    Anthocyanins can contribute to human health through preventing a variety of diseases. The uptake of these compounds from food and the parameters determining uptake efficiency within the human body are still poorly understood. Here we have employed a Caco-2 cell based system to investigate the transport of key antioxidant food components from sour cherry (Prunus cerasus L.) across the intestinal epithelial barrier. Anthocyanins and (-)-epicatechin were supplied in three contrasting matrices: fruit, processed fruit cherry juice, and polyphenolic fractions obtained by solid-phase extraction. Results show that both compound types behave differently. Fruit or juice matrices display comparable transport across the epithelial cell layer. The juice supplements sucrose and citric acid, which are regularly added to processed foods, have a positive effect on stability and transport. Polyphenolic fractions display a lower transport efficiency, relative to that of the fruit or juice, indicating the importance of food matrix components for intestinal absorption of polyphenols
    Interpreting experimental data on egg production - applications of dynamic differential equations
    France, J. ; Lopez, S. ; Kebreab, E. ; Dijkstra, J. - \ 2013
    Poultry Science 92 (2013)9. - ISSN 0032-5791 - p. 2498 - 2508.
    drosophila-melanogaster - gastrointestinal-tract - quantitative genetics - mathematical-models - phosphorus - calcium - absorption - fertility - algorithm
    This contribution focuses on applying mathematical models based on systems of ordinary first-order differential equations to synthesize and interpret data from egg production experiments. Models based on linear systems of differential equations are contrasted with those based on nonlinear systems. Regression equations arising from analytical solutions to linear compartmental schemes are considered as candidate functions for describing egg production curves, together with aspects of parameter estimation. Extant candidate functions are reviewed, a role for growth functions such as the Gompertz equation suggested, and a function based on a simple new model outlined. Structurally, the new model comprises a single pool with an inflow and an outflow. Compartmental simulation models based on nonlinear systems of differential equations, and thus requiring numerical solution, are next discussed, and aspects of parameter estimation considered. This type of model is illustrated in relation to development and evaluation of a dynamic model of calcium and phosphorus flows in layers. The model consists of 8 state variables representing calcium and phosphorus pools in the crop, stomachs, plasma, and bone. The flow equations are described by Michaelis-Menten or mass action forms. Experiments that measure Ca and P uptake in layers fed different calcium concentrations during shell-forming days are used to evaluate the model. In addition to providing a useful management tool, such a simulation model also provides a means to evaluate feeding strategies aimed at reducing excretion of potential pollutants in poultry manure to the environment.
    EURRECA—Estimating Zinc Requirements for Deriving Dietary Reference Values
    Lowe, N.M.M. ; Dykes, F.C. ; Skinner, A.L. ; Patel, S. ; Warthon-Medina, M. ; Decsi, T. ; Fekete, K. ; Souverein, O.W. ; Dullemeijer, C. ; Cavelaars, A.J.E.M. ; Serra-Majem, L. ; Nissensohn, M. ; Bel, S. ; Moreno, L.A. ; Hermoso, M. ; Vollhardt, C. ; Berti, C. ; Cetin, I. ; Gurinovic, M. ; Novakovic, R.N. ; Harvey, L.J. ; Collings, R. ; Hall-Moran, V. - \ 2013
    Critical Reviews in Food Science and Nutrition 53 (2013)10. - ISSN 1040-8398 - p. 1110 - 1123.
    current micronutrient recommendations - coronary-artery-disease - lung-cancer - serum zinc - genetic-polymorphism - stable-isotope - old patients - absorption - phytate - copper
    Zinc was selected as a priority micronutrient for EURRECA, because there is significant heterogeneity in the Dietary Reference Values (DRVs) across Europe. In addition, the prevalence of inadequate zinc intakes was thought to be high among all population groups worldwide, and the public health concern is considerable. In accordance with the EURRECA consortium principles and protocols, a series of literature reviews were undertaken in order to develop best practice guidelines for assessing dietary zinc intake and zinc status. These were incorporated into subsequent literature search strategies and protocols for studies investigating the relationships between zinc intake, status and health, as well as studies relating to the factorial approach (including bioavailability) for setting dietary recommendations. EMBASE (Ovid), Cochrane Library CENTRAL, and MEDLINE (Ovid) databases were searched for studies published up to February 2010 and collated into a series of Endnote databases that are available for the use of future DRV panels. Meta-analyses of data extracted from these publications were performed where possible in order to address specific questions relating to factors affecting dietary recommendations. This review has highlighted the need for more high quality studies to address gaps in current knowledge, in particular the continued search for a reliable biomarker of zinc status and the influence of genetic polymorphisms on individual dietary requirements. In addition, there is a need to further develop models of the effect of dietary inhibitors of zinc absorption and their impact on population dietary zinc requirements.
    Role of surface charge in bioavailability and biodistribution of tri-block copolymer nanoparticles in rats after oral exposure
    Bhattacharjee, S. ; Marcelis, A.T.M. ; Zuilhof, H. ; Woutersen, R.A. ; Rietjens, I.M.C.M. ; Alink, G.M. - \ 2013
    Toxicology Research 2 (2013)3. - ISSN 2045-452X - p. 187 - 192.
    silicon nanoparticles - gold nanoparticles - polystyrene particles - fischer-344 rats - cellular uptake - drug-delivery - in-vivo - cytotoxicity - toxicity - absorption
    Tri-block copolymer nanoparticles (TCNP) are increasingly utilized, especially in drug delivery and diagnostics platforms. From in vitro studies, surface charge was observed to influence the transport of TCNP across the Caco-2 monolayers grown on transwell inserts. The objective of this study was to investigate the influence of surface charge on bioavailability and biodistribution of TCNP after oral exposure in vivo and to compare with the in vitro data. To attain the set objectives, monodisperse (45 ± 5 nm), fluorescent and differently charged (positive and negative) TCNP were orally administered to inbred Fischer 344 rats. Blood samples were collected at t = 0, 1/2, 1, 2, 4 and 6 h followed by sacrifice of the animals and collection of the major organs (lungs, liver, kidney, spleen, brain, intestine, and tibia). Quantitative assessments of TCNP in blood and organs were performed by fluorescence measurements. TCNP of both surface charges got absorbed and appeared in the blood within 1/2 h of oral administration. No significant difference in bioavailability and biodistribution could be found between positive and negative TCNP. Both the TCNP, irrespective of charge, showed major accumulation in the liver, kidneys and spleen, were detected in the brain and did not cause any significant increase in the serum alkaline phosphatase levels. Contrary to the in vitro data, surface charge was not found to influence the in vivo bioavailability and biodistribution of TCNP after oral exposure. The obtained results encourage further development of such TCNP, especially for drug delivery purposes.
    Effect of algae- and silt concentration on clearance- and growth rate of the razor clam Ensis directus, Conrad
    Kamermans, P. ; Brummelhuis, E.B.M. ; Dedert, M. - \ 2013
    Journal of Experimental Marine Biology and Ecology 446 (2013). - ISSN 0022-0981 - p. 102 - 109.
    acclimated digestive responses - suspended bottom material - cerastoderma-edule l. - mytilus-edulis - particle selection - feeding bivalves - food quality - absorption - filtration - mussel
    Laboratory experiments were carried out with Ensis directus to estimate clearance rate and growth rate as a function of the amount of food and presence of silt. Two food levels were tested: low food availability (6.5 µg chla/l) and high food availability (16.5 µg chla/l) at four silt concentrations (0, 50, 150 and 300 mg/l). Clearance rates of E. directus varied between 0.7 and 5.9 l/h/g DW. At a silt concentration of 300 mg/l clearance rates were significantly lower (16–56%) than rates at 150 mg/l, 50 mg/l and 0 mg/l silt. This indicates that only the highest silt concentration induced a reduction in clearance rate. The tested food levels did not influence the clearance rate of E. directus. Maximum growth rate of E. directus was 0.24 mm increase in shell length and 2% increase in wet weight per day. Long-term (10 weeks) exposure to silt concentrations of 300 mg/l showed significantly higher growth than the 150 mg/l treatment. This indicates that exposure to a high silt concentration did not induce a reduction in growth, but stimulated growth. Long-term (10 weeks) exposure to a food level of 6.5 µg chla per litre reduced the shell growth of E. directus with 40% compared to growth at 16.5 µg chla per litre. The laboratory experiments suggest that E. directus is more sensitive to a reduction in algal concentration than to an increase in silt concentration.
    Isoenergetic Replacement of Fat by Starch in Diets for African Catfish (Clarias gariepinus): Effect on Water Fluxes in the Gastro Intestinal Tract
    Harter, T.S. ; Verreth, J.A.J. ; Heinsbroek, L.T.N. ; Schrama, J.W. - \ 2013
    PLoS ONE 8 (2013)2. - ISSN 1932-6203
    rainbow-trout - salmo-gairdneri - single meal - in-vivo - absorption - drinking - feed - eels - dry
    The effect of an isoenergetic replacement of dietary fat by starch, on chyme characteristics and water fluxes in the gastro intestinal tract (GIT) was assessed. Adult African catfish (Clarias gariepinus) were fed a starch (SD) or fat (FD) diet and groups of fish were dissected at 2, 5 and 8 h after the consumption of a single meal. Chyme was collected quantitatively and was analysed for osmolality and dry matter (DM) content. Postprandial water fluxes were calculated, while using yttrium oxide (Y2O3) as an inert marker to account for the absorption of DM along the GIT. The largest differences in chyme characteristics between diets were observed in the stomach and decreased towards subsequent compartments. A high initial osmotic pressure was measured in the stomach for both diets (up to 49862 mOsm kg21) and was likely the driver for the endogeneous water influx to this compartment. Large additions of water were recorded to the stomach and proximal intestine for both diets and absorption of water took place in the mid- and distal intestine. Interestingly, the dietary treatment had an impact on water balance in the stomach and proximal intestine of the fish, but not in the mid- and distal intestine. A strong complementary relationship suggested that 59% of the water fluxes in the proximal intestine could be explained by previous additions to the stomach. Therefore, a higher dietary inclusion of starch led to a shift in water additions from the proximal intestine to the stomach. However, the sum of water additions to the GIT was not different between diets and was on average 6.5260.85 ml water g21 DM. The interactions between osmoregulation and digestion, in the GIT of fed freshwater fish, deserve further attention in future research.
    Retrieval of spruce leaf chlorophyll content from airborne image data using continuum removal and radiative transfer
    Malenovsky, Z. ; Homolova, L. ; Zurita-Milla, R. ; Lukes, P. ; Kaplan, V. ; Hanus, J. ; Gastellu-Etchegorry, J.P. ; Schaepman, M.E. - \ 2013
    Remote Sensing of Environment 131 (2013). - ISSN 0034-4257 - p. 85 - 102.
    canopy reflectance models - optical-properties model - area index - hyperspectral data - forest canopies - precision agriculture - vegetation canopies - red - band - absorption
    We investigate combined continuum removal and radiative transfer (RT) modeling to retrieve leaf chlorophyll a & b content (Cab) from the AISA Eagle airborne imaging spectrometer data of sub-meter (0.4 m) spatial resolution. Based on coupled PROSPECT-DART RT simulations of a Norway spruce (Picea abies (L.) Karst.) stand, we propose a new Cab sensitive index located between 650 and 720 nm and termed ANCB650–720. The performance of ANCB650–720 was validated against ground-measured Cab of ten spruce crowns and compared with Cab estimated by a conventional artificial neural network (ANN) trained with continuum removed RT simulations and also by three previously published chlorophyll optical indices: normalized difference between reflectance at 925 and 710 nm (ND925&710), simple reflectance ratio between 750 and 710 nm (SR750/710) and the ratio of TCARI/OSAVI indices. Although all retrieval methods produced visually comparable Cab spatial patterns, the ground validation revealed that the ANCB650–720 and ANN retrievals are more accurate than the other three chlorophyll indices (R2 = 0.72 for both methods). ANCB650–720 estimated Cab with an RMSE = 2.27 µg cm- 2 (relative RRMSE = 4.35%) and ANN with an RMSE = 2.18 µg cm- 2 (RRMSE = 4.18%), while SR750/710 with an RMSE = 4.16 µg cm- 2 (RRMSE = 7.97%), ND925&710 with an RMSE = 9.07 µg cm- 2 (RRMSE = 17.38%) and TCARI/OSAVI with an RMSE = 12.30 µg cm- 2 (RRMSE = 23.56%). Also the systematic RMSES was lower than the unsystematic one only for the ANCB650–720 and ANN retrievals. Our results indicate that the newly proposed index can provide the same accuracy as ANN except for Cab values below 30 µg cm- 2, which are slightly overestimated (RMSE = 2.42 µg cm- 2). The computationally efficient ANCB650–720 retrieval provides accurate high spatial resolution airborne Cab maps, considerable as a suitable reference data for validating satellite-based Cab products.
    Improving the Capture of Co2 by Substituted Monoethanolamines: Electronic Effects of Fluorine and Methyl Substituents
    Gangarapu, S. ; Marcelis, A.T.M. ; Zuilhof, H. - \ 2012
    ChemPhysChem 13 (2012)17. - ISSN 1439-4235 - p. 3973 - 3980.
    main-group thermochemistry - free-energy perturbations - gas-phase basicities - ab-initio - noncovalent interactions - carbon-dioxide - amines - molecules - absorption - accuracy
    The influence of electronic and steric effects on the reaction between CO(2) and monoethanolamine (MEA) absorbents is investigated using computational methods. The pK(a) of the alkanolamine, the reaction enthalpy for carbamate formation, and the hydrolytic carbamate stability are important factors for the efficiency of CO(2) capture. The steric and electronic effects of CH(3), CH(2)F, CHF(2), CF(3), F, dimethyl, difluoro, and bis(2-trifluoromethyl) substituents at the a carbon of MEA on this reaction are investigated. Density functional theory (DFT) (B3LYP, M06-2X, M08-HX and M11-L) and ab initio methods [spin component-scaled second-order Møller-Plesset theory (SCS-MP2), G3], each coupled with solvent models [conductor-like polarizable continuum model (CPCM) and universal solvation models (SM8 and SMD)], are shown to yield accurately calculated pK(a) values of the substituted MEAs. Specifically, G3, SCS-MP2, and M11-L methods coupled with the SMD and SM8 solvation models perform well with a mean unsigned error (MUE) of only 0.15, 0.24 and 0.25 pK(a) units, respectively. SCS-MP2 is used to calculate the reaction enthalpy for carbamate formation and the carbamate stability towards hydrolysis. With the introduction of ß-fluoro substituents (especially the CH(2) F moiety) the reaction enthalpy for the formation of carbamates can be fine-tuned to be less exothermic than that using the unsubstituted MEA. This implies a reduced energy requirement for the solvent-regeneration step in the post-combustion carbon-capture method, which is currently the energy-limiting step in efficient CO(2) capture. ß-Fluoro-substituted MEAs are also shown to form less stable carbamates than MEA. Thus, ß-fluoro-substituted MEAs display a great potential for the use in the post-combustion carbon-capture process. Finally, a clear correlation is observed between the gas-phase basicity and the tendency to form carbamates. This allows for the rapid prediction of which species will be formed experimentally, and thus the CO(2)-absorbing capacities of alkanolamines can be estimated
    Changes in dietary macronutrient profile do not appear to affect endogenous urinary oxalate excretion in healthy adult cats
    Dijcker, J.C. ; Hagen-Plantinga, E.A. ; Hendriks, W.H. - \ 2012
    The Veterinary Journal 194 (2012)2. - ISSN 1090-0233 - p. 235 - 239.
    clinically normal cats - subcellular-distribution - feline uroliths - calcium - glyoxylate - protein - hydroxyproline - canine - metabolism - absorption
    The progressive increase in calcium oxalate uroliths reported in cats diagnosed with urolithiasis may partly be due to changes in nutrition. Since cats have a predominant mitochondrial alanine:glyoxylate aminotransferase 1 (AGT1) location, high carbohydrate intake may induce endogenous oxalate synthesis. This hypothesis was tested by feeding 12 adult, female cats three diets differing in macronutrients, namely, high protein (HP), high carbohydrate (HC) and high fat (HF), using a randomised Latin square design in a 36-day study. In addition to plasma, urine was collected quantitatively using modified litter boxes. A pilot study with four cats, conducted to determine the adaptation time of urinary oxalate (Uox) excretion to a dietary change, indicated a mean (±SEM) adaptation time of 5.9 ± 0.7 days, with the urinary oxalate:creatinine (Ox:Cr) ratio increasing from 36.1 ± 3.7 to 81.6 ± 2.3 mmol/mol. In the main study, plasma oxalate concentration was significantly lower when feeding the HP compared to the HF (P = 0.003) diet, whereas Uox excretion (µmol/kg BW0.75/day) and the urinary Ox:Cr ratio were unaffected by diet. The Uox concentration (mmol/L) was significantly lower when feeding the HP compared to the HC (P = 0.004) and HF (P = 0.001) diets. The results indicate that changes in macronutrient profile may not influence endogenous Uox excretion in cats but high dietary protein did reduce Uox concentration and may therefore help to lower the risk of calcium oxalate formation.
    The relationship between zinc intake and serum/plasma zinc concentration in pregnant and lactating women: A systematic review with dose-response meta-analyses
    Hall Moran, V. ; Skinner, A.L. ; Warthon Medina, M. ; Patel, S. ; Dykes, F. ; Souverein, O.W. ; Dullemeijer, C. ; Lowe, N.M.M. - \ 2012
    Journal of Trace Elements in Medicine and Biology 26 (2012)2-3. - ISSN 0946-672X - p. 74 - 79.
    mexican descent - plasma zinc - milk zinc - supplementation - iron - metabolism - absorption - serum
    Recommendations for zinc intake during pregnancy and lactation vary widely across Europe. Using data on zinc intake and biomarkers of zinc status reported in randomized controlled trials (RCTs) and observational studies can provide estimates of dose–response relationships that may be used for underpinning zinc reference values. This systematic review included all RCTs, prospective cohort studies, nested case–control studies and cross-sectional studies in healthy pregnant and lactating populations published by February 2010 which provided data on zinc intake and biomarkers of zinc status. An intake-status regression coefficient was calculated for each individual study and calculated the overall pooled and SE using random effects meta-analysis on a double log scale. The pooled dose–response relationship between zinc intake and zinc status found that a doubling of zinc intake was associated with an increase in serum/plasma zinc status by 3% in pregnant women and by 1% in lactating women. These modest associations are likely to reflect the low-moderate zinc bioavailability dietary patterns and the widespread use of other micronutrients in the populations included in this review, physiologic adjustments of zinc homeostasis, insensitivity of serum/plasma zinc as a biomarker of zinc status, and wide heterogeneity between study results which reflect real uncertainty in the current evidence base. Although this review provides useful information for dietary zinc requirements in populations vulnerable to zinc deficiency, it also highlights a need for further studies in pregnant and lactating women with different dietary patterns in order to provide useful complementary evidence that can be utilized when setting zinc recommendations as a basis for nutrition policies in Europe.
    Presence of Nano-Sized Silica during In Vitro Digestion of Foods Containing Silica as a Food Additive
    Peters, R.J.B. ; Kramer, E.H.M. ; Oomen, A.G. ; Rivera, Z.H. ; Oegema, G. ; Tromp, P.C. ; Fokkink, R.G. ; Rietveld, A. ; Marvin, H.J.P. ; Weigel, S. ; Peijnenburg, A.A.C.M. ; Bouwmeester, H. - \ 2012
    ACS Nano 6 (2012)3. - ISSN 1936-0851 - p. 2441 - 2451.
    gastrointestinal uptake - particle-size - bioaccessibility - model - contaminants - absorption - hazard
    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products subjected to in vitro digestion included (i) hot water, (ii) coffee with powdered creamer, (iii) instant soup, and (iv) pancake which either contained silica as the food additive E551, or to which a form of synthetic amorphous silica or 32 nm SiO2 particles were added. The results showed that, in the mouth stage of the digestion, nano-sized silica particles with a size range of 5–50 and 50–500 nm were present in food products containing E551 or added synthetic amorphous silica. However, during the successive gastric digestion stage, this nano-sized silica was no longer present for the food matrices coffee and instant soup, while low amounts were found for pancakes. Additional experiments showed that the absence of nano-sized silica in the gastric stage can be contributed to an effect of low pH combined with high electrolyte concentrations in the gastric digestion stage. Large silica agglomerates are formed under these conditions as determined by DLS and SEM experiments and explained theoretically by the extended DLVO theory. Importantly, in the subsequent intestinal digestion stage, the nano-sized silica particles reappeared again, even in amounts higher than in the saliva (mouth) digestion stage. These findings suggest that, upon consumption of foods containing E551, the gut epithelium is most likely exposed to nano-sized silica.
    Phytic Acid-to-Iron Molar Ratio Rather than Polyphenol Concentration Determines Iron Bioavailability in Whole-Cowpea Meal among Young Women
    Abizari, A.R. ; Moretti, D. ; Zimmerman, M.B. ; Armar-Klemesu, M. ; Brouwer, I.D. - \ 2012
    The Journal of Nutrition 142 (2012)11. - ISSN 0022-3166 - p. 1950 - 1955.
    sodium-bicarbonate - phaseolus-vulgaris - absorption - isotope - food - fortification - phytate - humans - beans - availability
    Limited data exist on iron absorption from NaFeEDTA and FeSO(4) in legume-based flours. The current study compared iron absorption from NaFeEDTA and FeSO(4) as fortificants within and between red and white varieties of cowpea with different concentrations of polyphenols (PP) but similar phytic acid (PA)-to-iron molar ratios. We performed a paired crossover study in young women (n = 16). Red-cowpea (high-PP) and white-cowpea (low-PP) test meals (Tubani) were each fortified with ((57)Fe)-labeled NaFeEDTA or ((58)Fe)-labeled FeSO(4) and were randomly administered. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. Per serving, the mean (±SD) PP concentrations of the white- and red-cowpea-based meals were 74 ± 3.6 and 158 ± 1.8 mg, respectively, and the molar ratio of PA to iron was 3.0 and 3.3. Iron bioavailabilities from red and white cowpeas were 1.4 and 1.7%, respectively, in NaFeEDTA-fortified meals and 0.89 and 1.2%, respectively, in FeSO(4)-fortified meals. Compared with FeSO(4), fortification with NaFeEDTA increased the amount of iron absorbed from either of the cowpea meals by 0.05 to 0.08 mg (P <0.05). Irrespective of the fortificant used, there was no significant difference in the amount of iron absorbed from the 2 varieties of cowpea. The results suggest that NaFeEDTA is more bioavailable in legume-based flours compared with FeSO(4). In cowpea-based flours, the major determinant of low iron absorption may be the high molar ratio of PA to iron and not variations in PP concentration
    Root water uptake as simulated by three water flow models
    Willigen, P. de; Dam, J.C. van; Javaux, M. ; Heinen, M. - \ 2012
    Vadose Zone Journal 11 (2012)3. - ISSN 1539-1663 - 14 p.
    flux potential approach - hydraulic conductivity - integrated approach - nutrient-uptake - architecture - system - absorption - scales - maize
    The objective of our study was to determine to what extent four root water uptake (RWU) models differed when tested under extreme conditions. Cumulative transpiration patterns were similar, contrary to the spatial extraction patterns. The analysis showed that both soil physical and root physiological factors are important for proper deterministic modeling of RWU. We compared four root water uptake (RWU) models of different complexity that are all embedded in greater soil water flow models. The soil models used were SWAP (one-dimensional), FUSSIM2 (two-dimensional), and RSWMS (three-dimensional). Within SWAP, two RWU functions were utilized (SWAP-macro and SWAP-micro). The complexity of the processes considered in RWU increases from SWAP-macro, to SWAP-micro, to FUSSIM2, to RSWMS. The objective of our study was to determine to what extent the RWU models differed when tested under extreme conditions: low root length density, high transpiration rate, and low water content. Comparison 1 looked at the results of the models for a scenario of transpiration and uptake and Comparison 2 studied compensation mechanisms of water uptake. The uptake scenario pertained to a long dry period with constant transpiration and a single rainfall event. As could be expected, the models yielded different results in Comparison 1, but the differences in cumulative transpiration were modest due to various feedback mechanisms. In Comparison 2, the cumulative effect of different feedback processes were studied. Redistribution of water due to soil pressure head gradients generated by water uptake led to an increase in cumulative transpiration of 32%, and the inclusion of compensation in uptake by the roots resulted in a further increase of 10%. Going from one- to three-dimensional modeling, the horizontal gradients in the soil and root system increased, which reduced the actual transpiration. The analysis showed that both soil physical and root physiological factors are important for proper deterministic modeling of RWU
    In vitro study of intestinal lipolysis using pH-stat and gas chromatography
    Helbig, A. ; Silletti, E. ; Timmerman, E. ; Hamer, R.J. ; Gruppen, H. - \ 2012
    Food Hydrocolloids 28 (2012)1. - ISSN 0268-005X - p. 10 - 19.
    pancreatic lipase activity - human gastric lipase - fat digestion - bile-salt - stereoselective hydrolysis - emulsion flocculation - droplet sizes - digestibility - triglycerides - absorption
    Developing healthy products requires in-depth knowledge of digestion. This study focuses on lipid digestion in relation to emulsion properties typically followed by pH-stat. Although this is a fast and easy method to follow the overall digestion, it provides no details on lipid digestion products. Thus, the aims of the present study were to use gas chromatography (GC) to determine all products present during lipolysis, i.e. monoglycerides (MG), diglycerides (DG) and triglycerides (TG), and to compare this method with the pH-stat method for free fatty acids (FFA). Fine, medium and coarse emulsions stabilized with two different emulsifiers (whey protein isolate (WPI) or gum arabic) were digested under in vitro intestinal conditions. Although the amount of FFA increased for both methods for WPI stabilized emulsions, the amount of FFA was 2–3 times higher when determined by GC compared with pH-stat. GC analysis showed decreasing amounts of MG and DG with increasing droplet size for both emulsions. Molar ratios of FFA/DG and MG/DG were twofold higher for WPI than for gum arabic stabilized emulsions. This indicates that the total production of lipolytic products (i.e. FFA + MG + DG) depends on the droplet size and the emulsifier but their proportions only depend on the emulsifier. Although pH-stat provides a fast measure of FFA release, it is influenced by the emulsifier type at the oil–water interface and therefore care should be taken when interpreting pH-stat results. We suggest combining this method with GC for accurate FFA determination and further evaluation of all lipolytic products.
    Selenium status in adult cats and dogs fed high levels of dietary inorganic and organic selenium
    Todd, S.E. ; Thomas, D.G. ; Bosch, G. ; Hendriks, W.H. - \ 2012
    Journal of Animal Science 90 (2012)8. - ISSN 0021-8812 - p. 2549 - 2555.
    brush-border membrane - pet foods - absorption - selenate - liver - rat - se
    Cats maintain higher blood Se concentrations compared to dogs and, unlike dogs, show no signs of chronic Se toxicity (selenosis) when fed dietary organic Se (selenomethionine) concentrations of 10 µg/g DM. This study investigated the response of cats and dogs to high dietary concentrations of sodium selenite and organic Se to determine differences in metabolism between both species. In 2 consecutive studies, 18 adult cats and 18 adult dogs of equal sex were fed a control diet (0.6 µg Se/g DM) or the control diet supplemented to 8 to 10 µg Se/g DM from Na2SeO3 or organic Se for 3 wk. All animals were fed the control diet 1 mo before the start of the study and blood samples were taken on d 0 and 21. The Se balance was assessed during the final week and a liver biopsy was obtained on the final day of the study. Measurements included plasma Se concentrations, plasma glutathione peroxidise (GPx) activities, plasma Se clearance, Se intake, and urinary Se excretion. No clinical signs of selenosis were observed in the cats or dogs, and apart from Se clearance, form of Se had no effect on any of the measurements. Apparent fecal Se absorption was greater in the dogs fed both forms of Se, while greater plasma Se concentrations were observed in the cats on both the control and supplemented diet (P = 0.034). Cats fed the supplemented diets had lower hepatic Se concentrations (P <0.001) and excreted more Se in urine (P <0.001) compared to dogs. Furthermore, cats fed the Na2SeO3 supplement had greater Se clearance rates than dogs (P <0.001). There was no effect of species on plasma GPx activity. We conclude that cats can tolerate higher dietary Se concentrations as they are more efficient at excreting excess Se in the urine and storing less Se in the liver
    Hepcidin is the major predictor of erythrocyte iron incorporation in anemic African children
    Prentice, A.M. ; Doherty, C.P. ; Abrams, S.A. ; Cox, S.E. ; Atkinson, S.H. ; Verhoef, J.C.M. ; Armitage, A.E. ; Drakesmith, H. - \ 2012
    Blood : journal of the American Society of Hematology 119 (2012)8. - ISSN 0006-4971 - p. 1922 - 1928.
    serum hepcidin - plasmodium-falciparum - malarial anemia - absorption - infection - inflammation - deficiency - metabolism - erythropoiesis - hypoferremia
    Iron supplementation strategies in the developing world remain controversial because of fears of exacerbating prevalent infectious diseases. Understanding the conditions in which iron will be absorbed and incorporated into erythrocytes is therefore important. We studied Gambian children with either postmalarial or nonmalarial anemia, who were given oral iron supplements daily for 30 days. Supplements administered on days 1 and 15 contained the stable iron isotopes 57Fe and 58Fe, respectively, and erythrocyte incorporation was measured in blood samples drawn 14 days later. We investigated how the iron-regulatory hormone hepcidin and other inflammatory/iron-related indices, all measured on the day of isotope administration, correlated with erythrocyte iron incorporation. In univariate analyses, hepcidin, ferritin, C-reactive protein, and soluble transferrin receptor (sTfR) strongly predicted incorporation of 57Fe given on day 1, while hepcidin, ferritin, and sTfR/log ferritin correlated with 58Fe incorporation. In a final multivariate model, the most consistent predictor of erythrocyte isotope incorporation was hepcidin. We conclude that under conditions of competing signals (anemia, iron deficiency, and infection), hepcidin powerfully controls use of dietary iron. We suggest that low-cost point-of-care hepcidin assays would aid iron supplementation programs in the developing world.
    Variation in rumen fermentation and the rumen wall during the transition period in dairy cows
    Bannink, A. ; Gerrits, W.J.J. ; France, J. ; Dijkstra, J. - \ 2012
    Animal Feed Science and Technology 172 (2012)1-2. - ISSN 0377-8401 - p. 80 - 94.
    subacute ruminal acidosis - chain fatty-acids - veal calf diets - early lactation - carbohydrate-composition - metabolic disorders - absorption - ph - adaptation - sodium
    Strong adaptive changes occur in the peri-parturient dairy cow related to a marked rise in dry matter intake and alteration in diet composition after calving. Early lactation dairy cattle are susceptible to metabolic disorders and impaired rumen function during the transition period, with detrimental effects on cow performance. For a quantitative understanding of the dietary effects on rumen function, several classes of influencing factors can be distinguished (intrinsic degradation characteristics of feed, characteristics of microbial activity, rumen fermentation conditions, rumen wall function). Interpretation of experimental results requires all these factors to be taken into consideration simultaneously. This contribution aimed to review the capacity of the rumen wall to adapt to the marked increase in feed intake by the post-parturient dairy cow. While the principle of distinct adaptations of the post-parturient rumen wall is generally accepted, literature is not always conclusive about the size of the effects. Virtually all studies on adaptation of the post-parturient rumen wall were performed post-mortem and with isolated tissue in vitro. Therefore, an in vivo trial with twelve rumen fistulated dairy cows is presented to support and discuss the various factors involved in this review. A faster (in 10 d) versus a slower (in 20 d) increment of starch-rich concentrate intake after calving was evaluated for effects on adaptive response of rumen epithelia and altered rumen functioning up to twelve weeks after calving. Results showed transient changes in rumen epithelia and suggest a different adaptive response of rumen epithelia during the first weeks of lactation due to differences in supplemental concentrate feeding. No evidence was found for any detrimental effect of a fast increment of concentrate intake on dry matter intake, rumen fermentation, and cow performance. Results in literature either confirm or contradict these findings, and they attribute either a more important role to molecular mechanisms in rumen epithelia or to cell proliferation and epithelial morphology. The different research methods adopted and the high variability of results obtained with this type of research strongly limit our understanding of the relative importance of cell metabolic changes, epithelia proliferation and rumen wall morphology. In conclusion, the ruminal epithelia in the peri-parturient cow responds in a coordinated manner to rapid dietary changes which is of high significance to maintain normal rumen function
    Apple extract induces increased epithelial resistance and claudin 4 expression in Caco-2 cells
    Vreeburg, R.A.M. ; Wezel, E.E. van; Ocana-Calahorro, F. ; Mes, J.J. - \ 2012
    Journal of the Science of Food and Agriculture 92 (2012)2. - ISSN 0022-5142 - p. 439 - 444.
    tight junction permeability - intestinal barrier function - in-vitro - disease - absorption - mechanisms - monolayer - kinase
    BACKGROUND: The small intestinal epithelium functions both to absorb nutrients, and to provide a barrier between the outside, luminal, world and the human body. One of the passageways across the intestinal epithelium is paracellular diffusion, which is controlled by the properties of tight junction complexes. We used a differentiated Caco-2 monolayer as a model for small intestinal epithelium to study the effect of crude apple extracts on paracellular permeability. RESULTS: Exposure of crude apple homogenate to the differentiated Caco-2 cells increased the paracellular resistance, determined as trans-epithelial electrical resistance (TEER). This increase was linearly related to the concentration of apple present. The TEER-enhancing effect of apple extract was due to factors mainly present in the cortex, and the induction was not inhibited by protein kinase inhibitors. Apple-induced resistance was accompanied by increased expression of several tight junction related genes, including claudin 4 (CLDN4). CONCLUSION: Crude apple extract induces a higher paracellular resistance in differentiated Caco-2 cells. Future research will determine whether these results can be extrapolated to human small intestinal epithelia
    Colonization-Induced Host-Gut Microbial Metabolic Interaction
    Claus, S.P. ; Ellero, S.L. ; Berger, B. ; Krause, L. ; Bruttin, A. ; Molina, J. ; Paris, A. ; Want, E.J. ; Waziers, I. de; Cloarec, O. ; Richards, S.E. ; Wang, Y. ; Dumas, M.E. ; Ross, A. ; Rezzi, S. ; Kochhar, S. ; Bladeren, P.J. van; LindOn, J.C. ; Holmes, E. ; Nicholson, J.K. - \ 2011
    mBio 2 (2011)2. - ISSN 2150-7511 - 8 p.
    diet-induced obesity - bile-acids - absorption - liver - mice - rat - cholesterol - bacteria - energy - flora
    The gut microbiota enhances the host’s metabolic capacity for processing nutrients and drugs and modulate the activities of multiple pathways in a variety of organ systems. We have probed the systemic metabolic adaptation to gut colonization for 20 days following exposure of axenic mice (n = 35) to a typical environmental microbial background using high-resolution 1H nuclear magnetic resonance (NMR) spectroscopy to analyze urine, plasma, liver, kidney, and colon (5 time points) metabolic profiles. Acquisition of the gut microbiota was associated with rapid increase in body weight (4%) over the first 5 days of colonization with parallel changes in multiple pathways in all compartments analyzed. The colonization process stimulated glycogenesis in the liver prior to triggering increases in hepatic triglyceride synthesis. These changes were associated with modifications of hepatic Cyp8b1 expression and the subsequent alteration of bile acid metabolites, including taurocholate and tauromuricholate, which are essential regulators of lipid absorption. Expression and activity of major drug-metabolizing enzymes (Cyp3a11 and Cyp2c29) were also significantly stimulated. Remarkably, statistical modeling of the interactions between hepatic metabolic profiles and microbial composition analyzed by 16S rRNA gene pyrosequencing revealed strong associations of the Coriobacteriaceae family with both the hepatic triglyceride, glucose, and glycogen levels and the metabolism of xenobiotics. These data demonstrate the importance of microbial activity in metabolic phenotype development, indicating that microbiota manipulation is a useful tool for beneficially modulating xenobiotic metabolism and pharmacokinetics in personalized health care.
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