Otto H Creutzenberg

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Male and female F-344 rats were exposed to 6 hr/day, 5 days/week for up to 24 months to a special test toner at 0, 1, 4, and 16 mg/m3, TiO2 at 5 mg/m3, or SiO2 at 1 mg/m3 by the inhalation route. 59Fe-labeled iron oxide and 85Sr-labeled polystyrene particles were periodically inhaled by the nose-only route and used to measure alveolar clearance rates during(More)
A chronic inhalation study of a test toner was conducted by exposure of groups of F-344 rats for 6 hr/day, 5 days/week for 24 months. The test toner was a special Xerox 9000 type xerographic toner, enriched in respirable-sized particles compared to commercial toner, such that it was about 35% respirable according to the ACGIH criteria. The target test(More)
Automobile exhaust catalytic converters emit fine dispersed elemental platinum, Pt (0), in the nanometer range coated on larger aluminium oxide carrier particles. A pre-requisite for a potential systemic toxic effect of the emitted platinum is its bioavailability which was investigated using laboratory animals. To this end, a model substance was synthesised(More)
In a chronic study of a test toner in F-344 rats an impairment of alveolar clearance and increased toner retention were observed at the high and, to a lesser degree, at the middle exposure level throughout the study. The objectives of the present study were: 1. To investigate the nature and the time course of test toner and surrogate tracer alveolar(More)
Biological effects of tailor-made multi-walled carbon nanotubes (MWCNTs) without functionalization were investigated in vivo in a two-year carcinogenicity study. In the past, intraperitoneal carcinogenicity studies in rats using biopersistent granular dusts had always been negative, whereas a number of such studies with different asbestos fibers had shown(More)
The objective of this study was to investigate whether the effects of dust overload are reversible upon cessation of subchronic exposure to test toner. Female rats were exposed 6 hr/day, 5 days/week for 3 months to a test toner at 0, 10, and 40 mg/m3. The retained quantity of test toner in the lungs at the end of exposure was 0.4 and 3.0 mg for the low and(More)
In previous investigations a reference test sample of prepared ceramic fibers called RCF1 induced lung tumors in a 2-yr inhalation study in rats. It was hypothesized that nonfibrous particles in RCF1 may have played a significant role. The objective of the present study was to compare lung retention and biological effects of another sample of ceramic(More)
The role of carcinogenic PAH in soot- and carbon black-related lung tumour induction in rats was investigated after intratracheal administration of carbon blacks (CB) and two types of diesel soot (DS), either as original or as toluene extracted particles. The total particle dose per animal was 15 mg subdivided into 16-17 weekly applications. There was one(More)
This study was designed to assess the lung clearance function in rats after subchronic exposure to p-aramid respirable fiber-shaped particulates (RFP). Male Wistar rats were exposed 6 hrs/day, 5 days/week for 3 months to 50, 200, and 800 RFP/ml measured by scanning electron microscopy (SEM). Recovery effects were followed up through 9 months postexposure.(More)
In order to quantify the relative oral bioavailability of 3-chloropropane-1,2-diol (3-MCPD) from 3-MCPD fatty acid diesters in vivo, 1,2-dipalmitoyl-3-chloropropane-1,2-diol (3-MCPD diester) and 3-MCPD were orally applied to rats in equimolar doses. In both cases, the time courses of 3-MCPD concentrations were measured in blood, various organs, tissues and(More)