Release of arachidonic and linoleic acid metabolites in skin organ cultures as characteristics of in vitro skin irritancy

In vitro techniques make a major contribution to the development of alternatives to the in vivo 'Draize' skin irritation test, and the development of sensitive and generally applicable in vitro endpoints of cutaneous toxicity is an area of intensive research. To investigate in vitro characteristics of cutaneous irritation, skin explants of...

Flow cytometric DNA measurement and cytomorphometric analysis of formalin fixed rat mammary tumours

Archival paraffin embedded material was used to examine whether additional quantitative criteria would be helpful to discriminate between histologically benign and malignant rat mammary tumours. To this end nuclear DNA content expressed as DNA ploidy index (DI) was measured using flow cytometry (FCM). A total of 63 benign and malignant mammary...

Cytotoxic and adaptive effects in rat nasal epithelium after 3-day and 13-week exposure to low concentrations of formaldehyde vapour

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...

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...

Subchronic (13-week) inhalation toxicity study of formaldehyde in male rats: 8 hour continuous versus 8 hour intermittent exposures

A subchronic (13-week) inhalation toxicity study with formaldehyde was carried out in male rats. The aim of the study was to find out whether excursions of the exposure by a factor 2, under conditions of concentration x time is constant, visibly affect the cytotoxic action of formaldehyde on the nasal epithelium. It was concluded that under the...

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...

Identification of mononuclear cells in human blood. II. Evaluation of morphological and immunological aspects of native and formaldehyde-fixed cell populations

The presence of surface-associated immunoglobulins and Fc receptors on mononuclear cells from normal human blood waas investigated by the direct immunofluorescence technique combined with phase-contrast microscopy. Formaldehyde-fixed cells were compared to unfixed cells and to cells preincubated at 37??C. In the unfixed samples a separate...