Gehaktbal ontbeert een goed verhaal
Scholten, Martin - \ 2017
Uit oogpunt van milieu en volksgezondheid is er veel voor te zeggen om de vleesconsumptie te verminderen en vleesproducten te ontwikkelen die voor een flink deel uit plantaardig materiaal bestaan. Technologisch kan tot 40 procent vlees vervangen worden zonder dat de consument er wat van merkt. Toch komt de vraag naar zulke ‘flexitarische’ vleesproducten niet van de grond, merkte Michiel Löwik in een rondgang langs enkele experts. Door alle ‘ruis’ van de laatste jaren blijkt het lastig om een aansprekend verhaal over vlees over het voetlicht te krijgen.
Genenweelde in oorsprongsgebieden essentieel voor toekomstige voedselzekerheid
Struik, Paul ; Hintum, Theo van - \ 2016
food security - genetic diversity - field crops - gene banks - plant breeding - genetic engineering - biodiversity - malus - varieties - kazakhstan - middle east
Behoud van genetische diversiteit is een belangrijk wapen om in te spelen op veranderingen in de leefomstandigheden van landbouwgewassen. Genenbanken vormen een onmisbare basis voor plantenveredeling, maar bieden onvoldoende waarborg voor toekomstige voedselzekerheid. Ook de lokale genenweelde in de oorsprongsgebieden moet behouden blijven, maar die wordt bedreigd door verstedelijking, verwaarlozing en klimaatverandering, constateert Michiel Löwik.
Richtlijnen goede voeding zijn een blijvertje
Kampman, Ellen - \ 2016
Nu het publicitaire stof rond de nieuwe Richtlijnen goede voeding 2015 van de Gezondheidsraad wat is neergedaald, is de vraag of er in 2020 nog ruimte is voor dergelijke algemene richtlijnen. De voorspelling is immers dat we straks een individueel voedingsadvies krijgen, gebaseerd op genenpaspoort en levensstijl. Volgens voedingsexperts Ellen Kampman en Wim Saris loopt het zo’n vaart niet. Hooguit komen er specifiekere richtlijnen voor verschillende bevolkingsgroepen. Freelance wetenschapsjournalist Michiel Löwik sprak met hen.
Mechanical and thermal stabilities of peptide amphipile fibres
Heuvel, M. van den; Baptist, H.G.M. ; Venema, P. ; Linden, E. van der; Löwik, D.W.P.M. ; Hest, J.C.M. van - \ 2011
Soft Matter 7 (2011). - ISSN 1744-683X - p. 9737 - 9743.
molecular architecture - aqueous-solution - amyloid fibrils - shear-flow - nanofibers - protein - polymerization - aggregation - scaffolds - hydrogels
In this study the thermal and mechanical stabilities of self-assembled fibres of palmitoyl functionalized GANPNAAG have been examined. The thermal stability was investigated with circular dichroism, dynamic light scattering and fluorescence measurements monitoring the disassembly upon heating and reassembly upon cooling. The determination of the temperature dependence of the critical aggregation concentration allowed us to estimate the thermodynamic parameters involved in the fibre formation process. The mechanical stability of the fibres was studied using flow-induced birefringence. The peptide based self-assembled structures were found to be thermally stable up to 70 [degree]C, while being fractured by moderate shear flow.
Assessment of intake from the diet
Kroes, R. ; Müller, D. ; Lambe, J. ; Löwik, M.R.H. ; Klaveren, J. van; Kleiner, J. ; Massey, R. ; Mayer, S. ; Urieta, I. ; Verger, P. ; Visconti, A. - \ 2002
Food and Chemical Toxicology 40 (2002). - ISSN 0278-6915 - p. 327 - 385.
exposure assessment - risk assessment - food consumption - concentration of chemicals in food - probabilistic modelling
Health Council of the Netherlands. Deoxynivalenol (DON).
Koeman, J.H. ; Feron, V.J. ; Fink-Gremmels, J. ; Lowik, M.R.H. ; Mulder, G.J. ; Sauer, P.J.J. ; Waard, M.A. de; Stoppelaar, J.M. de; Theelen, R.M.C. ; Pijls, L.T.J. - \ 2001
The Hague, the Netherlands : Health Council of the Netherlands - ISBN 9789055493944 - 70
fusarium - toxinogene schimmels - risicoschatting - tarwe - vomitoxine - toxinogenic fungi - risk assessment - wheat - vomitoxin
|Changes in the diet in the Netherlands: 1987-88 to 1992.
Lowik, M.R.H. ; Hulshof, K.F.A.M. ; Heijden, L.J.M. van der; Brussaard, J.H. ; Burema, J. ; Kistemaker, C. ; Vries, P.J.F. de - \ 1998
International Journal of Food Sciences and Nutrition 49 (1998). - ISSN 0963-7486 - p. S5 - S68.
Role of fibroblasts in the regulation of proinflammatory interleukin IL-1, IL-6 and IL-8 levels induced by keratinocyte-derived IL-1
Boxman, Ingeborg L.A. ; Ruwhof, Cindy ; Boerman, Otto C. ; Löwik, Clemens W.G.M. ; Ponec, Maria - \ 1996
Archives of Dermatological Research 288 (1996)7. - ISSN 0340-3696 - p. 391 - 398.
Fibroblast interaction - IL-1 receptor - Interleukin-1 - Interleukin-8 - Keratinocyte
In the epidermis, the keratinocytes are the first cells to be encountered by external stimuli and they are able to promote the inflammatory response by increased production and release of various cytokines. In their turn, these cytokines may directly affect the production of proinflammatory cytokines in human dermal fibroblasts. In addition, in both epithelial and mesenchymal cells cytokine production may be modulated by their mutual interaction, and thereby regulate the inflammatory response. The present study aimed to examine the role of fibroblasts in the regulation of proinflammatory IL-1, IL-6 and IL-8 levels induced by keratinocyte-derived IL-1. The data show that in fibroblasts exposed to conditioned media derived from cultures of normal human keratinocytes or squamous carcinoma cells (SCC-4), both the IL-8 and IL-6 mRNA expression as well as protein production were elevated. In addition, it was shown that these effects were induced by IL-1α. The IL-1α-induced increase in IL-8 and IL-6 production, both on the protein level as well as on the mRNA level, were concentration dependent and occurred almost simultaneously. While the induction of IL-6 and IL-8 occurred simultaneously, the IL-6 mRNA remained elevated for longer. In contrast to increased IL-6 and IL-8 production the IL-1α levels markedly decreased upon culturing of fibroblasts in keratinocyte-derived conditioned medium. From internalization experiments it could be concluded that binding of IL-1 to IL-1 receptors, and its subsequent internalization and intracellular degradation is the most likely mechanism involved in the reduction of IL-1 levels by fibroblasts. Comparing the rate of IL-1 reduction in the presence of various cell types indicated that the rate of IL-1 reduction is directly related to the number of IL-1 receptors found on these cell types. In conclusion, these results indicate that the release of IL-1α by activated keratinocytes may act as an inducer of IL-8 and IL-6 production in neighbouring fibroblasts. This may be an important pathway for the amplification of the inflammatory response. The amounts of both cytokines produced by fibroblasts were at least two to three orders of magnitude higher than those produced by keratinocytes, suggesting an important role of fibroblasts in the general inflammatory response. Furthermore, fibroblasts might be involved in turning off this inflammatory response by reducing IL-1 levels, most likely via IL-1 receptor-mediated uptake.
Parathyroid hormone related protein and interleukin-6 mRNA expression in larynx and renal cell carcinomas from normocalcaemic and hypercalcaemic patients
Schweitzer, D.H. ; Boxman, I.L.A. ; Lowik, C.W.G.M. ; Krieken, J.H.J.M. Van; Weissglas, M.G. ; Baatenburg De Jong, R.J. ; Papapoulos, S.E. - \ 1995
Journal of clinical pathology 48 (1995)10. - ISSN 0021-9746 - p. 896 - 900.
Interleukin-6 - Parathyroid hormone related protein - Renal cell carcinoma - Squamous cell carcinoma
Aims-To determine the expression of parathyroid hormone related protein (PTHrP) and interleukin-6 (IL-6) mRNAs and their possible relation in malignant tumours, derived from patients with and without hypercalcaemia, commonly associated with humoral hypercalcaemia of malignancy. Methods-PTHrP and IL-6 mRNA expression was studied by northern blot analysis in tumour specimens from 13 consecutive patients. Six patients (two with hypercalcaemia) had squamous cell carcinomas of the larynx and seven (one with hypercalcaemia) had renal cell carcinomas. Results-There was no relation between the histological features of the tumours and the expression of either PTHrP or IL-6 mRNAs. PTHrP mRNA was detected in all squamous cell carcinomas, expression being highest in the two patients with hypercalcaemia. In the renal cell carcinomas PTHrP mRNA was expressed only in the patient with hypercalcaemia. IL-6 mRNA was detected in nearly all tumours studied but there was no apparent relation between its expression and that of PTHrP mRNA or serum calcium concentrations. Conclusions-PTHrP mRNAexpression is increased in patients with hypercalcaemia but is not related to IL-6 mRNA expression. The results suggest a quantitative relation between PTHrP gene expression and hypercalcaemia, and imply that different mechanisms account for this expression in squamous and renal cell carcinomas.
Differential regulation of plasminogen activation in normal keratinocytes and SCC-4 cells by fibroblasts
Boxman, I.L.A. ; Quax, P.H.A. ; Lowik, C.W.G.M. ; Papapoulos, S.E. ; Verheijen, J. ; Ponec, M. - \ 1995
Journal of Investigative Dermatology 104 (1995)3. - ISSN 0022-202X - p. 374 - 378.
cocultures - PAI-1 - PAI-2 - squamous carcinoma cells - u-PA - u-PA receptor
The plasminogen activator (PA)/plasmin system is thought to be involved in processes such as tumor invasion and wound healing, during which epithelial and mesenchymal cells come close together. However, information on regulation of the PA/plasmin system during epithelial-mesenchymal interactions is scarce. Therefore, we examined the in vitro modulation of the production and activity of the components of the PA/plasmin system in squamous carcinoma cells (SCC-4) and normal human keratinocytes in relation to cell density and the presence or absence of fibroblasts (3T3 cells). There was an inverse relation between cell density and mRNA expression for urokinase-type plasminogen activator (u-PA) and u-PA receptor in both SCC-4 cells and keratinocytes. In addition, such a relation was found for plasminogen-activator inhibitor types 1 (PAI-1) and 2 (PAI-2) in SCC-4 monocultures, but not in keratinocyte monocultures. In contrast to monocultures, variation of cell density did not affect the mRNA expression of the components of the PA/plasmin system in cocultures of SCC-4 cells or keratinocytes with 3T3 cells. However, the relative expression of mRNAs in co-cultures was clearly different from that in monocultures, especially at low cell density. For most of the components of the PA/plasmin system, a decrease in mRNA expression and u-PA receptor protein was observed at most cell densities, whereas for PAI-1 only in keratinocytes a marked increase was documented. Zymography of supernatants revealed that the levels of both free u-PA and PA-PAI were increased in SCC-4/3T3 co-cultures, whereas in keratinocyte/3T3 co-cultures, only levels of the PA-PAI complex were increased, while the amount of free u-PA activity decreased. This occurred despite the increased u-PA immunoreactivity and was probably caused by the markedly elevated levels of immunoreactive PAI-1. The results of the present study reveal that the production and synthesis of various components of the PA/plasmin system in keratinocytes and SCC-4 cells depend on the density of epithelial cells and are modulated by fibroblasts, probably through a direct cell-cell or cell-matrix contact. Fibroblast-induced modulations are similar in keratinocytes and SCC-4 cells except for the regulation of PAI-1, which is markedly enhanced only in keratinocytes. This suggests that the modulation of PA activity in the direct microenvironment may be different under physiologic and pathologic conditions.
|Variability of serum 25(OH)D across Europe and its determinants.
Wielen, R.P.J. van der; Löwik, M.R.H. ; Groot, C.P.G.M. de - \ 1995
In: Book of abstracts 7th European Nutrition Conf. Vienna (1995)
Serum vitamin D concentrations among elderly people in Europe.
Wielen, R.P.J. van der; Löwik, M.R.H. ; Berg, H. van den; Groot, C.P.G.M. de; Haller, J. ; Moreiras, O. ; Staveren, W.A. van - \ 1995
The Lancet 346 (1995). - ISSN 0140-6736 - p. 207 - 210.
|Ontwikkeling van een vragenlijst naar voedingskennis.
Paas, G.R.A. ; Schneijder, P. ; Wedel, M. ; Stafleu, A. ; Löwik, M.R.H. - \ 1994
Nederlands Tijdschrift voor Dietisten 49 (1994). - ISSN 0166-7203 - p. 78 - 81.
Modulation of IL-6 production and IL-1 activity by keratinocyte-fibroblast interaction
Boxman, Ingeborg ; Löwik, Clemens ; Aarden, Lucien ; Ponec, Maria - \ 1993
Journal of Investigative Dermatology 101 (1993)3. - ISSN 0022-202X - p. 316 - 324.
interleukin-6/interleukin-1/normal human keratinocytes/squamous carcinoma cells/fibroblast co-cultures
The present study was undertaken to investigate whether modulation of interleukin-6 and interleukin-1 production occurs owing to keratinocyte-fibroblast interaction. Normal human keratinocytes or squamous carcinoma cells were cultured either alone or in the presence of human foreskin fibroblasts or murine 3T3 cells. All cells tested produced interleukin-6, and interleukin-6 levels were markedly increased when normal or malignant keratinocytes were co-cultured with fibroblasts. The bioassay (species independent) and enzyme-linked immunosorbent assay (specific for human interleukin-6) together with use of complementary DNA probes specific for human or murine interleukin-6 revealed that fibroblasts are responsible for increased interleukin-6 levels. Moreover, interleukin-6 levels were increased when fibroblasts were cultured in conditioned media derived from normal human keratinocytes and squamous carcinoma cells-4 cultures. Interleukin-1α secreted by normal human keratinocytes and squamous carcinoma cells-4 cells was mainly responsible for the increased interleukin-6 production in fibroblasts. Although interleukin-1 activity increased linearly with the incubation time in squamous carcinoma cells-4 mono-cultures, interleukin-1 activity was low and remained unchanged in squamous carcinoma cells-4/3T3 co-cultures. Low interleukin-1 activity was most probably not due to inhibition of interleukin-1α production in squamous carcinoma cells-4/3T3 co-cultures because interleukin-lα messenger RNA expression in squamous carcinoma cells-4 cells remained unchanged in the presence of 3T3 cells. Furthermore, when 3T3 cells were incubated in conditioned medium derived from squamous carcinoma cells-4 cells, high interleukin-1 activity decreased to an undetectable level, suggesting that fibroblasts are involved in the suppression of interleukin-1 activity. The remaining interleukin-1 activity, however, was sufficient for maximal induction of interleukin-6 production in fibroblasts. These results suggest that the interaction between epithelial and mesenchymal cells is at least partly initiated by interleukin-lα secreted by the activated epithelial cell during skin injury or tumor invasion. Interleukin-1 in turn can induce modulation of the synthesis of various pro-inflammatory mediators and proteases in surrounding fibroblasts. An enhanced proteolytic activity and/or a possible induced production of an interleukin-1 inhibitor in fibroblasts and/or a receptor-mediated interleukin-1 consumption by fibroblasts will cause a decrease in interleukin-1 activity and thus exert a negative feedback.
|Risk groups among elderly people in The Netherlands: a review (Dutch Nutrition Surveillance System).
Lowik, M.R.H. ; Berg, H. van den; Westenbrink, S. ; Schrijver, J. ; Meulmeester, J.F. ; Kok, F.J. ; Ockhuizen, T. - \ 1992
Age et Nutrition 3 (1992). - ISSN 1158-0259 - p. 72 - 77.
|Hematocrit and cardiovasculair risk factors among elderly men and women (Dutch Nutrition Surveillance System).
Lowik, M.H.R. ; Odink, J. ; Kok, F.J. ; Ockhuizen, T. - \ 1992
Gerontology 38 (1992). - ISSN 0304-324X - p. 205 - 213.
|Clustering of dietary variables and other lifestyle factors (Dutch Nutrition Surveillance System).
Hulshof, K.F.A.M. ; Wedel, M. ; Lowik, M.R.H. ; Kok, F.J. ; Kistemaker, C. ; Hermus, R.J.J. ; Hoor, F. ten; Ockhuizen, Th. - \ 1992
Journal of Epidemiology and Community Health 46 (1992). - ISSN 0143-005X - p. 417 - 424.
|Inconsistency of associations among anthropometric measurements in elderly Dutch men and women.
Minten, K.F.A.M. ; Löwik, M.R.H. ; Deurenberg, P. ; Kok, F.J. - \ 1992
Journal of the American Dietetic Association 91 (1992). - ISSN 0002-8223 - p. 1408 - 1412.
|Diet and other life style factors in different socio-economic groups in The Netherlands.
Hulshof, K.F.A.M. ; Kok, F.J. ; Lowik, M.R.H. ; Wedel, M. ; Aarnink, E.J.M. ; Brants, H.A.M. - \ 1991
In: Proc. Symp. Socio-economic health differences, J.P. Mackenbach (ed.). Rotterdam - p. 81 - 82.
|Diet and other life-style factors in high and low socio-economic groups.
Hulshof, K.F.A.M. ; Lowik, M.R.H. ; Kok, F.J. - \ 1991
European Journal of Clinical Nutrition 45 (1991). - ISSN 0954-3007 - p. 441 - 450.