Safety evaluation of pectin-derived acidic oligosaccharides (pAOS): Genotoxicity and sub-chronic studies

Pectin-derived acidic oligosaccharides (pAOS) are non-digestible carbohydrates to be used in infant formulae and medical nutrition. To support its safety, the genotoxic potential of pAOS was evaluated. pAOS was not mutagenic in the Ames test. Positive results were obtained in the chromosome aberration test only at highly cytotoxic concentrations...

Androgenic activity in surface water samples detected using the AR-LUX assay: Indications for mixture effects

This paper describes the screening of 22 extracts from 18 different aquatic environmental samples for androgenic activity, including indirect and interactive effects on androgen receptor (AR)-mediated signal transduction, using the AR-LUX bioassay. Four samples, originating from an industrial wastewater treatment plant (WTP) or the river Meuse,...

The pro-oxidant chemistry of the natural antioxidants vitamin C, vitamin E, carotenoids and flavonoids

Natural antioxidants like vitamin C, vitamin E, carotenoids, and polyphenols like flavonoids, are at present generally considered to be beneficial components from fruit and vegetables. The anti-oxidative properties of these compounds are often claimed to be responsible for various beneficial health effects of these food ingredients. Together...

Interactions of prostaglandin A2 with the glutathione-mediated biotransformation system

The cyclopentenone prostaglandin A2 (PGA2) is known to inhibit cell proliferation, and metabolism of this compound thus might be important in controlling its ultimate function. The glutathione-related metabolism of PGA2 was therefore investigated both with purified glutathione S-transferase P1-1 (GSTP1-1) and with IGR-39 human melanoma cells....

Interactions of prostaglandin A2 with the glutathione-mediated biotransformation system

Absence of an inhibitory effect of a vegetables-fruit mixture on the initiation and promotion phases of azoxymethane-induced colorectal carcinogenesis in rats fed low- or high-fat diets

The potential inhibitory effects of a vegetables-fruit mixture on the initiation and promotion phases of azoxymethane-induced colorectal carcinogenesis were examined in rats fed low- or high-fat diets. Rats were fed low-fat diets (20 energy percent, Diets A and B) or high-fat diets (40 energy percent, Diets C and D), supplemented with a...

Modulation of dietary fat-enhanced colorectal carcinogenesis in N-methyl-N'-nitro-N-nitrosoguanidine-treated rats by a vegetables-fruit mixture

The modulation of a vegetables-fruit mixture on N-methyl-N'-nitro-N- nitrosoguanidine (MNNG)-induced colorectal carcinogenesis was studied in rats maintained on a low- or a high-fat diet. Far this purpose, 120 rats received a semisynthetic diet without (Groups A and C) or with a vegetables-fruit mixture (19.5% wt/wt, Groups B and D) for 35 weeks...

Transport and metabolism of glutathione conjugates of menadione and ethacrynic acid in confluent monolayers of rat renal proximal tubular cells

Confluent monolayers of primary rat renal proximal tubular (RPT) cells were used to compare transepithelial transport and concomitant metabolism of two different glutathione (GSH) S-conjugates. For the GSH-conjugated quinone compound, [35S]GSH-conjugated menadione (MGNQ), no specific transepithelial transport was observed. Most likely, [35S]MGNQ...

Cytotoxicity of 2-tert-butyl hydroquinone glutathione conjugates after apical and basolateral exposure of rat renal proximal tubular cell monolayers

Confluent monolayers of renal proximal tubular (RPT) cells cultured on porous supports were used to investigate the cytotoxicity induced by glutathione conjugates of 2-tert-butyl-(1,4)-hydroquinone (SG-TBHQ) after apical and basolateral exposure. As judged from lactate dehydrogenase (LDH) leakage, cytotoxicity was observed after basolateral...

Vitamin A and β-carotene influence the level of benzo[a]pyrene-induced DNA adducts and DNA-repair activities in hamster tracheal epithelium in organ culture

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...

Nitrate, nitrite and N-nitroso compounds

The role of oxidative metabolism in hexachlorobenzene-induced porphyria and thyroid hormone homeostasis: a comparison with pentachlorobenzene in a 13-week feeding study

Hexachlorobenzene (HCB) induces a broad spectrum of effects including disturbances in the heme synthesis (porphyria) and in thyroid hormone homeostasis. For most of its effects, biotransformation of the parent compound seems to be a prerequisite. The present study was designed to assess the relevance of the oxidative metabolites in HCB-induced...

Effect of retinol and cigarette-smoke and condensate on dye-coupled intercellular communication between hamster tracheal epithelial cells

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...

A carcinogenicity study with mutagenic organic concentrates of drinking-water in the Netherlands

The carcinogenicity in male and female Wistar SSP TOX rats of organic drinking-water concentrates that are positive in the Ames test was studied at thr. Chemicals/CAS: Carcinogens, Environmental; Mutagens; Water Pollutants; Water Pollutants, Chemical.

Identification and toxicological evaluation of chlorinated dibenzofuran and chlorinated naphthalene in two commercial polychlorinated biphenyls

In a previous study (Vos & Koeman, Toxic. appl. Pharmac. 1970. In press) a significant difference in toxicity was found between three commercial polychlorinated biphenyl (PCB) preparations, high mortality, liver necrosis and chick oedema-like lesions being associated with only two of the compounds tested. In the present study, column and gas...