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Prinsen, M.K. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)The enucleated eye test with chicken eyes (CEET) obtained from an abattoir proved to be a valuable and practical alternative for the 'traditional' enucleated eye test with eyes of laboratory rabbits. Since 1992, the CEET has been incorporated in standard contract toxicity testing at the Toxicology Division of the TNO Nutrition and Food Research...article 1996
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Gee, J.M. (author), Wortley, G.M. (author), Johnson, I.T. (author), Price, K.R. (author), Rutten, A.A.J.J.L. (author), Houben, G.F. (author), Penninks, A.H. (author), TNO Voeding (author)The effects of potato and tomato glycoalkaloids and a saponin mixture from Gypsophila were investigated in cytotoxicity studies (neutral red uptake, mitochondrial MTT reduction and release of lactate dehydrogenase), using cultured cell lines of rat and human intestinal mucosal epithelium. Experiments to assess the effects of these compounds on...article 1996
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van Vliet, A.K. (author), van Thiel, G.C.F. (author), Huisman, R.H. (author), Moshage, H. (author), Yap, S.H. (author), Cohen, L.H. (author), TNO Preventie en Gezondheid (author)The three vastatins examined, lovastatin, simvastatin and pravastatin, are equally strong inhibitors of the sterol synthesis in human hepatocytes in culture with IC50-values of 4.1, 8.0 and 2.0 nM, respectively. However, in the human extrahepatic cells: umbilical vascular endothelial cells, retinal pigment epithelial cells, cornea fibroblasts...article 1995
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Wolterbeek, A.P.M. (author), Roggeband, R. (author), Baan, R.A. (author), Feron, V.J. (author), Rutten, A.A.J.J.L. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)Vitamin A and β-carotene protect against respiratory tract cancer by inhibiting the formation of DNA damage and controlling cellular proliferation and differentiation, Recently, it has been shown that the p53 tumor-suppressor gene plays a crucial role in the etiology of respiratory tract cancer. In the present study, we investigated the...article 1995
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Wolterbeek, A.P.M. (author), Roggeband, R. (author), van Moorsel, C.J.A. (author), Baan, R.A. (author), Koeman, J.H. (author), Feron, V.J. (author), Rutten, A.A.J.J.L. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)Although most studies concerning the effect of vitamin A and β-carotene on chemical carcinogenesis are focused on tumour promotion and progression, these compounds may affect initiation as well. In this study the influence of vitamin A and β-carotene on unscheduled DNA synthesis (UDS) was investigated in hamster tracheal epithelium in organ...article 1995
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Spit, B.J. (author), Bretschneider, F. (author), Hendriksen, E.G.J. (author), Kuper, C.F. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The distribution of nerve fibres in the mucosa of the nasal septum of the rat was investigated by means of transmission electron microscopy on transverse and tangential ultrathin sections. Near the basement membrane of respiratory and squamous epithelium, a rather dense network of unmyelinated nerve fibres occurs. Some fibres in the respiratory...article 1993
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Instituut voor verouderings- en vaatziekten onderzoek TNO (author), HogenEsch, H. (author), Gijbels, M.J.J. (author), Offerman, E. (author), van Hooft, J. (author), van Bekkum, D.W. (author), Zurcher, C. (author)Chronic proliferative dermatitis is a new spontaneous mutation in C57BL/Ka mice. Breeding results suggest an autosomal recessive mode of inheritance. Mutant mice develop skin lesions at the age of 5 to 6 weeks. The lesions occur in the ventral and dorsal skin of the body, whereas ears, footpads, and tail are not involved. The lesions are...article 1993
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Centraal Instituut voor Voedingsonderzoek TNO (author), Jonker, D. (author), Woutersen, R.A. (author), van Bladeren, P.J. (author), Til, H.P. (author), Feron, V.J. (author)In a 4-wk study, 10-wk-old Wistar rats were fed the nephrotoxins hexachloro-1,3-butadiene (HCBD), mercuric chloride, d-limonene and lysinoalanine either alone or in combination. These nephrotoxins damage epithelial cells of the proximal tubules, but by different mechanisms. Each chemical was given alone at a Minimum-Nephrotoxic-Effect Level ...article 1993
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Instituut voor Verouderings- en Vaatziekten Onderzoek TNO Gezondheidsorganisatie TNO (author), Geus, B.de (author), HogenEsch, H. (author), Kubo, R.T. (author), Rozing, J. (author)Murine intestinal intraepithelial lymphocytes (ilEL) represent a heterogeneous population of cells which contains both TCRαβ+ and TCRγδ+ cells. In contrast to the TCRαβ+ cell population in peripheral lymphoid organs, the TCRαβ+ ilEL contain high numbers of Thy-1-cells. This negativity of ilEL for Thy-1, a glycosylphosphatidyl inositol (GPI)...article 1992
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Zwart, A. (author), Woutersen, R.A. (author), Wilmer, J.W.G.M. (author), Spit, B.J. (author), Feron, V.J. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)To study in detail possible effects of low concentrations of formaldehyde on the nasal epithelium, Wistar rats were exposed to 0, 0.3, 1 and 3 ppm formaldehyde vapour for 6 h/day, 5 days/week during 3 days or 13 weeks, using in vivo [3H]thymidine labeling for cell proliferation studies, and light and electron microscopy for detecting...article 1988
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de Groot, A.P. (author), Feron, V.J. (author), Immel, H.R. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)In previous studies we observed an increased incidence of hyperplasia in the epithelium of the urinary bladder of rats fed cereal-based stock diet supplemented with 6% monosodium glutamate (MSG) for 3 months. Hyperplasia was not enhanced, however, when 6% MSG was fed in a purified casein diet. Further studies have been conducted to identify the...article 1988
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Feron, V.J. (author), Bruyntjes, J.P. (author), Woutersen, R.A. (author), Immel, H.R. (author), Appelman, L.M. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)Male Wistar rats were exposed to 0, 10 or 20 ppm formaldehyde vapour for 4, 8 or 13 weeks (6 h/day; 5 days/week), and were then observed for periods up to 126 weeks. Transient growth retardation occurred in both test groups. Death rate was not noticeably affected by formaldehyde. Despite recovery periods of at most 126 weeks, the nasal...article 1988
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Rutten, A.A.J.J.L. (author), Wilmer, J.W.G.M. (author), Beems, R.B. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The effects of cigarette smoke condensate (CSC) and all-trans retinol on the cell proliferative activity of vitamin A-deprived hamster tracheal epithelium have been studied in vitamin A-deficient, serum-free, hormone-supplemented medium in organ culture. In the absence of retinol, CSC induced a dose-dependent increase in labelig index (LI)...article 1988
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Rutten, A.A.J.J.L. (author), Beems, R.B. (author), Wilmer, J.W.G.M. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The effects of all-trans retinol and cigarette smoke condensate (CSC) on tissue morphology and cellular differentiation were investigated in vitamin A-deprived tracheal epithelium cultured in vitamin A- and serum-free hormone-supplemented medium. Physiological retinol concentrations prevented the development of hyperplasia and squamous...article 1988
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Rutten, A.A.J.J.L. (author), Jongen, W.M.F. (author), de Haan, L.H.J. (author), Hendriksen, E.G.J. (author), Koeman, J.H. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The dye-coupled intercellular communication across gap junctions in primary hamster tracheal epithelial cells has been studied in serum-free, hormone-supplemented medium. In the absence of vitamin A, non-cytotoxic concentrations of cigarette-smoke condensate (CSC) inhibited intercellular communication between tracheal epithelial cells in a...article 1988
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Centraal Instituut voor Voedingsonderzoek TNO (author), Rutten, A.A.J.J.L. (author), Beems, R.B. (author), Wilmer, J.W.G.M. (author), Feron, V.J. (author)The pseudostratified tracheal epithelium, composed of a heterogeneous phenotypically varying cell population, was studied with respect to the in vitro cell proliferative activity of differentiated epithelial cells. Ciliated tracheal epithelial cells so far have been considered to be terminally differentiated, nonproliferating cells. Tracheal...article 1988
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Appelman, L.M. (author), Woutersen, R.A. (author), Feron, V.J. (author), Hooftman, R.N. (author), Notten, W.R.F. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The effects of exposure pattern on the toxicity of acetaldehyde vapour were investigated in 4-week inhalation studies. Male rats were exposed to 500 or 150 and 110 ppm for 6 h per day/5 days per week. One group of animals was exposed without interruption, the exposure of a second group was interrupted for 1.5 h between the first and second 3-h...article 1986
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Instituut CIVO-Toxicologie en voeding TNO (author), Woutersen, R.A. (author), Appelman, L.M. (author), van Garderen-Hoetmer, A. (author), Feron, V.J. (author)Male and female Wistar rats were exposed to acetaldehyde vapour at nominal concentrations 0, 750, 1500 or 3000/1000 ppm during 6 h/day, 5 days/week for up to 28 months. Major compound-related effects included increased mortality, growth retardation, nasal tumours, and non-neoplastic nasal changes in each of the test groups. The treatment-related...article 1986
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Reuzel, P.G.J. (author), Feron, V.J. (author), Spit, B.J. (author), Beems, R.B. (author), Kroes, R. (author), Instituut CIVO-Toxicologie en voeding TNO (author)Cofactors involved in respiratory tract carcinogenesis were studied in Syrian golden hamster or in rats using benzo(a)pyrene as the carcinogenic agent. These factors included severe tissue tissue damage induced by electro-coagulation, glass fibers administered by intratracheal instillation, acetaldehyde as irritant vapor, food restriction, and...article 1983
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Centraal Instituut voor Voedingsonderzoek TNO (author), Appelman, L.M. (author), Woutersen, R.A. (author), Feron, V.J. (author)The 4-h LC50 of acetaldehyde in rats was determined and found to be 13,300 ppm (24.0 g/m3 air). In a 4-week study groups of 10 male and 10 female rats were exposed to 0, 400, 1000, 2200 or 5000 ppm acetaldehyde for 6 h/day, 5 days/week. Treatment-related changes observed at the 5000 ppm level included dyspnoea and excitation during the first 30...article 1982