Keratinocyte gene expression profiles discriminate sensitizing and irritating compounds

Many chemicals can induce allergic contact dermatitis. Because evaluation of skin sensitizing potential by animal testing is prohibited for cosmetics, and screening of many chemicals is required within Registration, Evaluation, Authorisation and Restriction of Chemicals, urgent need exists for predictive in vitro assays to identify contact...

Subtoxic concentrations of allergenic haptens induce LC migration and maturation in a human organotypic skin explant culture model: A novel method for identifying potential contact allergens

The accelerated migration of Langerhans cells (LCs) out of the epidermis and up-regulation of maturation markers, upon treatment with subtoxic concentrations of chemicals, were used as the criteria to determine the potential of allergenic chemicals capable of inducing a hapten-specific delayed-type hypersensitivity reaction. Here we report the...

Employment and disability for work in patients with COPD: A cross-sectional study among Dutch patients

Objectives: The aim was to gain insight into work experiences and problems of subjects with chronic obstructive pulmonary disease (COPD) to develop more effective guidelines for preventing work disability and work loss. Methods: A total of 617 patients aged 45-60, recruited from pulmonary outpatient clinics and general practices, completed a...

Skin irritants and contact sensitizers induce Langerhans cell migration and maturation at irritant concentration

Skin irritants and contact allergens reduce the number of Langerhans cells (LCs). It has been assumed that this reduction is due their migration to the draining lymph node (LN) for initiating immune sensitization in a host. Skin irritation, however, as opposed to contact allergy is not considered to be an immunological disease. Nevertheless,...

Assessment of contact allergens by dissociation of irritant and sensitizing properties

The human organotypic skin explant culture (hOSEC) model is a promising alternative in vitro model for screening contact allergens. In this model, the chemical-induced migration of Langerhans cells (LCs) out of the epidermis, evaluated after a 24-h exposure period, is used as a measure of sensitizer potential. As skin irritants can also induce...

Respiratory allergy and pulmonary irritation to trimellitic anhydride in Brown Norway rats

Occupational exposure to low-molecular-weight (LMW) allergens such as acid anhydrides can result in occupational asthma, an allergic disease characterized by episodic airway obstruction, airways inflammation, and non specific airways hyperresponsiveness. Since LMW irritants can provoke rather similar effects and since most, if not all, LMW...

Approaches to induce and elicit respiratory allergy: Impact of route and intensity of exposure

Although a number of test protocols have been developed to predict respiratory allergenic potential, none of these are widely applied or fully accepted. However, given the serious health problems caused by respiratory allergy and the ever-increasing stream of new chemicals into workplaces, early identification of chemical respiratory allergens...

An analysis of human response to the irritancy of acetone vapors

Studies on the irritative effects of acetone vapor in humans and experimental animals have revealed large differences in the lowest acetone concentration found to be irritative to the respiratory tract and eyes. This has brought on much confusion in the process of setting occupational exposure limits for acetone. A literature survey was carried...

An in vitro model for detecting skin irritants: Methyl green-pyronine staining of human skin explant cultures

We evaluated the potential of human organotypic skin explant cultures (hOSECs) for screening skin irritants. Test chemicals were applied to the epidermis of the skin explants which were incubated for 4, 24 or 48 h in tissue culture medium. A decrease in epidermal RNA staining, visualised in frozen sections using a modified methyl-green pyronine ...

Methyl green-pyronine staining of porcine organotypic skin explant cultures: An alternative model for screening for skin irritants

We describe a new alternative method for screening for skin irritants by using fresh intact porcine skin biopsies. Test chemicals were applied to the epidermis of the biopsies, which were then incubated for different times in tissue culture medium at 37°C and with 5% carbon dioxide. A decrease in epidermal keratinocyte RNA staining, visualised...

The use of human keratinocytes and human skin models for predicting skin irritation: The report and recommendations of ECVAM Workshop 38

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. 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...