Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Records 1 - 20 / 33

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: q=Versloot
Check title to add to marked list
Bioavailability of lutein from a lutein-enriched egg-yolk beverage and its dried re-suspended versions
Bunger, M. ; Quataert, M.C.J. ; Kamps, L.M. ; Versloot, P. ; Hulshof, P.J.M. ; Togtema, K.A. ; Amerongen, A. van; Mensink, M.R. - \ 2014
International Journal of Food Sciences and Nutrition 65 (2014)7. - ISSN 0963-7486 - p. 903 - 909.
density-lipoprotein cholesterol - macular pigment density - age-related maculopathy - zeaxanthin concentrations - serum concentrations - dietary-cholesterol - optical-density - clinical-trial - beta-carotene - eye disease
Drying a fresh lutein-enriched egg-yolk beverage would extend its shelf life, however, functional properties should not be affected. It was investigated whether consumption of a dried beverage containing lutein-enriched egg-yolk significantly increases serum lutein. One-hundred healthy young subjects participated in this 6-weeks randomized controlled study. Subjects consumed either a “plain” control beverage (n¿=¿26), a fresh lutein-enriched egg-yolk beverage (n¿=¿25), a dried version of this beverage (n¿=¿25), or a beverage composed of the dried individual components of the drink (n¿=¿24). The fresh and both dried versions of the lutein-enriched egg-yolk beverage were able to increase serum lutein levels after 6 weeks of consumption (lutein change: -38¿±¿47¿nmol/L, +304¿±¿113¿nmol/L, +148¿±¿79¿nmol/L and +178¿±¿83¿nmol/L for control, fresh, dried and combined dried group respectively; p¿
Critical assessment of three high performance liquid chromatography analytical methods for food carotenoid quantification
Dias, M.G. ; Oliveira, L. ; Camoes, M.F.G.F.C. ; Nunes, B. ; Versloot, P. ; Hulshof, P.J.M. - \ 2010
Journal of Chromatography. A, Including electrophoresis and other separation methods 1217 (2010)21. - ISSN 0021-9673 - p. 3494 - 3502.
vegetables - fruits
Three sets of extraction/saponification/HPLC conditions for food carotenoid quantification were technically and economically compared. Samples were analysed for carotenoids a-carotene, ß-carotene, ß-cryptoxanthin, lutein, lycopene, and zeaxanthin. All methods demonstrated good performance in the analysis of a composite food standard reference material for the analytes they are applicable to. Methods using two serial connected C18 columns and a mobile phase based on acetonitrile, achieved a better carotenoid separation than the method using a mobile phase based on methanol and one C18-column. Carotenoids from leafy green vegetable matrices appeared to be better extracted with a mixture of methanol and tetrahydrofuran than with tetrahydrofuran alone. Costs of carotenoid determination in foods were lower for the method with mobile phase based on methanol. However for some food matrices and in the case of E–Z isomer separations, this was not technically satisfactory. Food extraction with methanol and tetrahydrofuran with direct evaporation of these solvents, and saponification (when needed) using pyrogallol as antioxidant, combined with a HPLC system using a slight gradient mobile phase based on acetonitrile and a stationary phase composed by two serial connected C18 columns was the most technically and economically favourable method
Vitamin A equivalency of ß-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect
Bouwman, C.A. ; West, C.E. ; Breemen, R.B. van; Zhu, D. ; Siebelink, E. ; Versloot, P. ; Hulshof, P.J.M. ; Lieshout, M. van; Russel, F.G.M. ; Schaafsma, G. ; Naber, T.H.J. - \ 2009
British Journal of Nutrition 101 (2009)12. - ISSN 0007-1145 - p. 1837 - 1845.
mass-spectrometry - leafy vegetables - dark-green - bioavailability - retinol - humans - bioconversion - serum - consumption - spinach
Data on the vitamin A equivalency of ß-carotene in food are inconsistent. We quantified the vitamin A equivalency (¿g) of ß-carotene in two diets using the dual-isotope dilution technique and the oral¿faecal balance technique. A diet-controlled, cross-over intervention study was conducted in twenty-four healthy adults. Each subject followed two diets for 3 weeks each: a diet containing vegetables low in ß-carotene with supplemental ß-carotene in salad dressing oil ('oil diet') and a diet containing vegetables and fruits high in ß-carotene ('mixed diet'). During all 6 weeks, each subject daily consumed a mean of 55 (sd 0·5) ¿g [13C10]ß-carotene and 55 (sd 0·5) ¿g [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of ß-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum and from apparent absorption by oral-faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]ß-carotene in oil of 3·4 ¿g (95 % CI 2·8, 3·9), thus the bio-efficacy of the ß-carotene in oil was 28 % in the presence of both diets. However, data from oral-faecal balance estimated vitamin A equivalency as 6:1 ¿g (95 % CI 4, 7) for ß-carotene in the 'oil diet'. ß-Carotene in the 'oil diet' had 2·9-fold higher vitamin A equivalency than ß-carotene in the 'mixed diet'. In conclusion, this extrinsic labelling technique cannot measure effects of mixed vegetables and fruits matrices, but can measure precisely the vitamin A equivalency of the ß-carotene in oil capsules
Determinants of CD4 counts among HIV-Negative ethiopians: Role of body mass index, gender, cigarette smoking, khat (Catha edulis) chewing, and possibly altitude?
Abuye, C. ; Tsegaye, A. ; West, C.E. ; Versloot, P. ; Sanders, E.J. ; Wolday, D. ; Hamann, D. ; Wit, T.F.R. De; Fontanet, A.L. - \ 2005
Journal of Clinical Immunology 25 (2005)2. - ISSN 0271-9142 - p. 127 - 133.
human-immunodeficiency-virus - reference ranges - lymphocyte subsets - adult ethiopians - natural-history - cell counts - t-cells - infection - interleukin-2 - parameters
To study the determinants of CD4% and CD4 counts among HIV-negative Ethiopians, and to identify factors susceptible to explain the low CD4 counts observed among Ethiopian subjects. Cohort studies among factory workers in Akaki and Wonji, Ethiopia. Clinical and laboratory examinations, including determination of HIV serological status and T-cell subsets, were performed during follow-up visits every six months. In addition, micronutrients (retinol, carotenoids, tocopherol, transferrin receptor, and selenium) plasma concentrations were determined in a subset of 38 HIV-positive and 121 HIV-negative participants. HIV-negative participants with at least one CD4 count measurement were 157 females in Akaki, 203 males in Akaki, and 712 males in Wonji. CD4 counts were independently and positively associated with body mass index (through an increase in lymphocyte counts), female gender (through an increase in CD4%), cigarette smoking (through an increase in CD4%), khat chewing (through an increase in both lymphocyte counts and CD4%), and Akaki study site (through a large increase in lymphocyte counts compensating a decrease in CD4%). Intestinal parasitic infections were not associated with CD4% or CD4 counts. Retinol, carotenoids, and -tocopherol plasma concentrations decreased with HIV infection and advancing immunosuppression, but were not associated with CD4 counts among HIV-negative subjects. Low body mass index among Ethiopians may have contributed to their overall low CD4 counts. Other factors remain to be elucidated
Photoacoustic measurement of lutein in biological matrix
Bicanic, D.D. ; Luterotti, S. ; Becucci, M. ; Fogliano, V. ; Versloot, P. - \ 2005
Journal de Physique IV France 125 (2005). - ISSN 1155-4339 - p. 825 - 828.
performance liquid-chromatography - thermal lens detection - trans-beta-carotene - ultrasensitive determination - vegetable-oils - hplc-tls
Photoacoustic (PA) spectroscopy was applied for the first time to quantify lutein in a complex biological matrix. Standard addition of lutein to a biological low-lutein matrix was used for the calibration. The PA signal was found linearly proportional (R > 0.98) to lutein concentration up to 0.3% (w/w). The dynamic range of concentrations extends to 1% (w/w) lutein. For a given experimental set-up the responsivity of PA detector within the range of linearity was estimated to 1.1 mV/1% lutein. Precision of repeated analyses is good with average RSD values of 4 and 5% for blanks and spiked samples, respectively. The analytical parameters indicate that the PA method is fast and sensitive enough for quantification of lutein in supplementary drugs and in the lutein-rich foods.
Vitamin A equivalency of beta-carotene in oil in healthy Dutch adults measured using specifically 13C-labeled beta-carotene and retinol
Bouwman, C.A. ; West, C.E. ; Breemen, R.B. van; Zhu, D. ; Lieshout, M. van; Siebelink, E. ; Versloot, P. ; Naber, A.H.J. - \ 2004
- 1 p.
Bioavailability and bioefficacy in healthy Dutch adults of Beta-carotene in mixed diet and in oil measured using specifically 13C-labelled beta-carotene and retinol.
Bouwman, C.A. ; West, C.E. ; Breemen, R.B. van; Zhu, D. ; Lieshout, M. van; Siebelink, E. ; Versloot, P. ; Naber, A.H.J. - \ 2004
Comparison of bioavailability of lutein and beta-carotene in spinach and pumpkin consumed by Indonesian children
Lieshout, M. van; West, C.E. ; Bovenkamp, P. van de; Roekel, T. van; Versloot, P. ; Permaesih, D. ; Muhilal, ; Creemers, A.F.L. ; Verhoeven, M.A. ; Lugtenburg, J. ; Wang, Y. ; Sun, Y. ; Xu, X. ; Breemen, R.B. - \ 2001
In: Report of the XX International Vitamin A Consultative Group meeting
Application of the classic limulus test and the quantitative kinetic chromogenic LAL method for evaluation of endotoxin concentration in indoor air
Gorny, R. ; Douwes, J. ; Versloot, P. ; Heederik, D. ; Dutkiewicz, J. - \ 1999
Annals of Agricultural and Environmental Medicine 6 (1999). - ISSN 1232-1966 - p. 45 - 51.
Sodium-iodide transporter (sit) expression in fetal tissues during mild (mid) and moderate iodine defficiency.
Schröder-van der Elst, J.P. ; Heide, D. van der; Versloot, P.M. ; Ruby, S. ; Obregón, M.J. - \ 1998
Journal of Endocrinological Investigation 21 (1998)suppl. to no. 4. - ISSN 0391-4097 - p. 3 - 6.
Contribution of 3,5,3'-tri-iodothyronine produced locally from thyroxine in several maternal tissues of the near-term pregnant rat.
Versloot, P.M. ; Heide, D. van der; Schröder-van der Elst, J.P. ; Boogerd, L. - \ 1998
European Journal of Endocrinology 139 (1998). - ISSN 0804-4643 - p. 448 - 453.
Effects of marginal iodine defiency on thyroid hormone production, distribution and transport in nonpregnant and near-term pregnant rats.
Versloot, P.M. ; Heide, D. van der; Schröder-van der Elst, J.P. ; Boogerd, L. - \ 1998
European Journal of Endocrinology 138 (1998). - ISSN 0804-4643 - p. 713 - 718.
Maternal thyroxine and 3,5,3'-tri-iodothyronine kinetics in near-term pregnant rats at two different levels of hypothyroidism.
Versloot, P.M. ; Heide, D. van der; Schröder-van der Elst, J.P. ; Boogerd, L. - \ 1998
European Journal of Endocrinology 138 (1998). - ISSN 0804-4643 - p. 113 - 119.
Thyroid hormones and iodide in the near-term pregnant rat
Versloot, P. - \ 1998
Agricultural University. Promotor(en): D. van der Heide. - S.l. : Versloot - ISBN 9789054858065 - 133
metabolisme - schildklierhormonen - jodide - hormonale controle - voortplanting - ontwikkeling - schildklier - bevruchting - zwangerschap - geboorte - ratten - metabolism - thyroid hormones - iodide - hormonal control - reproduction - development - thyroid gland - fertilization - pregnancy - birth - rats
<p>Thyroid hormones, thyroxine (T4) and 3,5,3'-triiodothyronine (T3), are produced by the thyroid gland. To synthesize thyroid hormones the thyroid needs iodide. The uptake of iodide as well as the production and secretion of T4 and T3 by the thyroid gland is regulated by thyrotropin (TSH), which is produced by the pituitary. However, most of the biologically active form, T3, is produced from T4 via monodeiodination in peripheral tissues.</p><p>This reaction is catalyzed by the deiodinases, type I (ID-I) in liver and kidney, and type II (ID-II) in the central nervous system and brown adipose tissue (BAT). T4 and T3 concentrations differ in the various tissues, like the contribution of T3 produced locally from T4. A large portion of the T3 produced in the liver enters the circulation, whereas T3 produced in the brain and cerebellum is mainly used locally.</p><p>The production, distribution and transport of thyroid hormones are influenced by several (patho)physiological conditions. In this study we concentrated on the effects of pregnancy on maternal thyroid hormone metabolism. It is well known that thyroid hormones are very important for normal fetal development, especially of the central nervous system. During development thyroid hormones produced by the mother, mainly T4, contribute to the fetal thyroid hormone pools before and also after onset of fetal thyroid function. Insufficient production of maternal thyroid hormones during pregnancy can result in permanent brain damage in the offspring.</p><p>At the end of gestation the concentrations of T4 and T3 in maternal plasma and tissues have decreased. In order to gain more insight into the effects of pregnancy on the production, distribution, and transport of thyroid hormones in the mother we performed kinetic experiments with T4 and T3 using nonpregnant and near-term pregnant rats (chapter 2). A bolus injection of [125I]T4 and [131I]T3 was given, and blood samples were taken at regular times during the next twenty-four hours.</p><p>Physiological para-meters of the production, interpool transport, distribution and metabolism of T4 and T3 were estimated by means of a three-compartment model. According to this model three compartments can be distinguished: 1. the plasma; 2. the fast pool; and 3. the slow pool. Liver and kidney are considered to be the main components of the fast pool, whereas skin, muscles and brain belong to the slow pool.</p><p>In the near-term pregnant rat the production and distribution of T4 remained unchanged. The transport of T4 from plasma to the fast pool was more than tripled, whereas transport to the slow pool remained constant. We suggest that in the near-term pregnant rat available T4 was distributed between the maternal and fetal compartments by means of very fast transport. This hypothesis is based on the fact that it seems unlikely that the transport of T4 to maternal liver and kidney, which are considered to be the main components of the fast pool, will have increased that much in the near-term pregnant rat. This was confirmed by the results of steady-state, double isotopic experiments using nonpregnant and near-term pregnant rats (chapter 3).</p><p>In this study, the rats received a continuous simultaneous infusion of [125I]T4 and [131I]T3 in order to achieve equilibrium in all tissues. With this method it was possible to calculate the T4 and T3 concentrations, the relative contributions of plasma-derived vs. locally produced T3, the thyroidal T4 and T3 secretion rates, and the plasma-to-tissue ratios for T4 and T3. Indeed, the transport of T4 to liver and kidney, as well as almost all other maternal organs, was diminished. Since the production of T4 remained unchanged this implies that T4 is transported to another compartment, i.e. the feto-placental compartment. This compartment was not measured in these studies.</p><p>The plasma appearance rate for T3 remained constant in the near-term pregnant rat. This was accomplished by an increase in the secretion of T3 by the thyroid and a decrease in locally produced T3. Less T3 was transported from plasma to liver, kidney, BAT and pituitary. ID-I activity in liver, and ID-II activity in the brain both increased during pregnancy. However, this did not result in an increase in the local conversion of T4 to T3 in these tissues. In the liver the contribution of T3 produced locally remained constant, while in the brain even a decrease was found.</p><p>The insufficient availability of T4 in maternal tissues, as demonstrated by the lower T4 concentrations, might explain the discrepancy between deiodinase activities and the local production of T3. The transport of T4 to the feto-placental compartment resulted indirectly in a deficiency of T3 in the maternal organs. We can conclude that pregnancy affects maternal thyroid hormone metabolism. The mother has to share the available thyroid hormones, especially T4, with the fetuses.</p><p>Iodide is an essential element for the synthesis of thyroid hormones. In rats the fetal thyroid is capable of producing thyroid hormones on day 18 of gestation. Iodide is transported across the placenta from the maternal to the fetal circulation. In chapter 4 we assessed iodide uptake by the maternal thyroid, while the iodide uptake by the fetal thyroid was estimated. We measured the in vivo uptake of 125I by the thyroid continuously. By using the specific activity of iodide in the urine we were able to calculate the absolute iodide uptake in the thyroid.</p><p>Pregnancy resulted in a decrease in the absolute thyroidal iodide uptake. On day 20 of pregnancy the fetal thyroid is already capable of concentrating iodide. However, the difference in absolute iodide uptake by the maternal thyroid, compared to nonpregnant controls, cannot fully be explained by the transport of iodide to the fetal compartment and/or the mammary glands. The decrease in iodide uptake by the maternal thyroid has no impact on the thyroidal production of thyroid hormones.</p><p>Iodine deficiency can lead to disturbed physical and mental development. In large populations in the world iodine intake is marginally deficient. For this reason a marginal iodine deficiency, instead of the more common severe iodine deficiency, was induced in our rats. We used this model to study the effects of marginal iodine deficiency on iodide metabolism (thyroidal iodide uptake; chapter 4) and thyroid hormone metabolism (kinetic experiments; chapter 5) in near-term pregnant rats.</p><p>The absolute iodide uptake by the maternal thyroid was not affected by marginal iodine deficiency. The decreased plasma inorganic iodide was compensated by an increase in thyroidal clearance. A similar compensation was not found for the fetus; the uptake of iodide by the fetal thyroid decreased by 50 % during marginal iodine deficiency. During this marginal iodine deficiency plasma T4 and T3 remained constant in nonpregnant as well as near-term pregnant rats. The production rate and the plasma clearance rate for T4 were both decreased.</p><p>No effects of marginal iodine deficiency on pool sizes and transport rates were found for nonpregnant rats. In the near-term pregnant rat marginal iodine deficiency resulted in a marked decrease in the transport of T4 from plasma to the fast pool. For T3 an increase in the production rate and plasma clearance rate was found for nonpregnant, marginally iodine- deficient rats, while these parameters were slightly decreased in near-term pregnant rats. Marginal iodine deficiency induced a 50 % decrease in the interpool transport rates of T3 between plasma and the fast pool in near-term pregnant rats. The hepatic activity of ID-I was increased as a result of marginal iodine deficiency in nonpregnant as well as near-term pregnant rats.</p><p>On the basis of the results of thyroid hormone studies in normal pregnant rats (chapter 2 and 3) we suggest that during marginal iodine deficiency less maternal T4 is available for the fetal compartment. Together with the lower uptake of iodide by the fetal thyroid this can lead to diminished levels of thyroid hormone of maternal and fetal origin in the fetal organs. In this case, marginal iodine deficiency will have a negative effect on fetal development, especially of the brain.</p><p>Another situation which irreversibly affects fetal brain development is maternal hypothyroidism. Two different levels of hypothyroidism were induced in female rats, by giving thyroidectomized rats two different doses of T4 and T3. The effects of hypothyroidism on maternal thyroid hormone metabolism in near-term pregnant rats (kinetic experiment, chapter 6) were studied. Plasma T4 and T3 levels were very low severely hypothyroid animals, whereas only plasma T3 was decreased in the mildly hypothyroid group. Even during this mild hypothyroidism profound alterations in the transport rates of T4 were found compared to intact, pregnant rats. The transport of T4 from plasma to the fast pool was decreased. Therefore, it appears that even during mild hypothyroidism the transport of T4 to the feto-placental compartment is affected.</p><p>In conclusion: Pregnancy seriously affects the maternal thyroid hormone status. Despite an unchanged thyroidal production of T4, all maternal T4 tissue levels are decreased. Less T4 is available for the mother because of the transport of T4 to the feto-placental compartment. Indirectly this results in a T3-deficiency in most maternal organs. During marginal iodine deficiency and maternal hypothyroidism the transport of maternal T4 to the feto-placental compartment is diminished, whereas during marginal iodine deficiency the availability of iodine for fetal thyroid hormone syn-thesis is also decreased. Eventually this can result in impaired development of the fetal central nervous system.</p>
Effects of marginal iodine deficiency during pregnancy: iodide uptake by the maternal and fetal thyroid.
Versloot, P.M. ; Schröder-van der Elst, J.P. ; Heide, D. van der; Boogerd, L. - \ 1997
American Journal of Physiology. Endocrinology and Metabolism 273 (1997). - ISSN 0193-1849 - p. E1121 - E1126.
Early effects of neonatal diabetes on thyroid hormone dependent parameters in the rat.
Heide, D. van der; Schöder-van der Elst, J.P. ; Versloot, P.M. ; Viets, T.C. ; Bakel, M.E. ; Hooiveld, G.J.E.J. ; Vos, I.H.C. - \ 1995
Thyroid 5 (1995)Suppl. 1. - ISSN 1050-7256 - p. S252 - S252.
Influence of various dust sampling and extraction methods on the measurement of airborne endotoxin.
Douwes, J. ; Versloot, P. ; Hollander, A. ; Heederik, D. ; Doekes, G. - \ 1995
Applied and Environmental Microbiology 61 (1995). - ISSN 0099-2240 - p. 1763 - 1769.
Different responses of thyroid Hormone metabolism to a marginal iodine deficiency in nonpregnant and near term pregnant rats.
Versloot, P.M. ; Boogerd, L. ; Luttikholt, A.L.M. ; Rij, M. van; Heide, D. van der - \ 1994
European Journal of Endocrinology 130 (1994). - ISSN 0804-4643 - p. 45 - 45.
Thyroxine and 3,5,3'-triiodothyronine production, metabolism, and distribution in pregnant rat near term.
Versloot, P.M. ; Gerritsen, J. ; Boogerd, L. ; Schröder-van der Elst, J.P. ; Heide, D. van der - \ 1994
American Journal of Physiology. Endocrinology and Metabolism 267 (1994). - ISSN 0193-1849 - p. E860 - E867.
Blootstelling aan biologische agentia bij werknemers in de huisvuilverwerking.
Amelsfoort, L.G.P.M. van; Heederik, D.J.J. ; Versloot, P. - \ 1994
Unknown Publisher - 24 p.
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.