Alternative acute inhalation toxicity testing by determination of the concentration-time-effect relationship

Alternative acute inhalation toxicity testing by determination of the concentration-time-mortality relationship: Experimental comparison with standard LC50 testing

A new design for acute inhalation toxicity testing was evaluated and compared with results obtained according to OECD guideline 403. The new design consists of a range-finding test, which is compatible with a conventional limit test, and can be followed by determination of a concentration-time-mortality relationship, enabling calculation of LC50...

Comparative sensitivity of histo-pathology and specific lung parameters in the detection of lung injury

The sensitivity of different parameters for the determination of lung injury caused by nitrogen dioxide (NO2) was investigated. Male rats were exposed to concentrations of 0, 4, 10 or 25 ppm NO2 for 6 h/day, for 7, 14 or 21 days. Histopathology of the nasal cavity, larynx, trachea and lungs was compared with the changes in macrophage function...

Nasal tumours in rats after short-term exposure to a cytotoxic concentration of formaldehyde

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...

Significance of the dog as 'second animal species' in toxicity testing for establishing the lowest 'no-toxic-effect level'

The toxicity data of 66 compounds adequately tested in the rat (as 'prime animal species') and in the dog (as 'second animal species') were studied to find out for how many of these compounds the study in dogs led to a lower 'no-toxic-effect level' (NTEL) than that found in the rat. From a quantitative point of view such information would...

Effect of variable versus fixed exposure levels on the toxicity of acetaldehyde in rats

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...

Inhalation toxicity of acetaldehyde in rats. III. Carcinogenicity study

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...

Concentration-time mortality response relationship of irritant and systemically acting vapours and gases

This report presents the re-evaluation of the raw data of previously published acute inhalation toxicity studies of some volatile industrial chemicals. In these studies both concentration and exposure time were varied. The raw data were obtained from an extensive literature search and were subjected to probit analysis. The results show that the...

Inhalation toxicity of acetaldehyde in rats. II. Carcinogenicity study: Interim results after 15 months

Male and female Wistar rats were exposed to acetaldehyde vapour at concentrations of 0, 750, 1500 and 3000/1000 ppm during 6 h/day, 5 days/week for up to 27 months. The present paper deals with the results obtained during the first 15 months of the study, including interim kills after 13, 26 and 52 weeks. Major compound-related lesions occurred...

Acute inhalation toxicity study of ammonia in rats with variable exposure periods

The acute inhalation toxicity of ammonia was examined in rats using various exposure concentrations and exposure periods. Groups of male and female rats were exposed to dynamic atmospheres containing different concentrations of ammonia for 10, 20, 40 or 60 min. The aim of the study was to establish the relationship between exposure concentration...

Inhalation toxicity of acetaldehyde in rats. I. Acute and subacute studies

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...

Repeated exposure to alpha-ethylacrolein vapour: Subacute toxicity study in rats

The subacute inhalation toxicity of ??-ethylacrolein was examined in rats by repeated exposure of 4 groups of 10 males and 10 females each to ??-ethylacrolein vapour at concentrations of 0, 2.0, 9.8 or 48.4 ppm, respectively, (6 h/day, 5 days/week) for a period of 13 weeks. The effects at 48.4 ppm were found to include growth retardation, focal...