Effect of chlorpyrifos on the profile of subpopulations immunocompetent cells B, T and NK in in vivo model.

Background: Current studies have indicated many environmental factors, such as pesticides, that cause immune system disorders through inducing changes in humoral and cellular responses thereby increasing the risk of contracting infectious diseases and cancer. The literature suggests that low exposures to certain organophosphorus pesticides stimulate the immune system, whilst high exposures result in decreased function. Precise mechanisms for the fall in immunocompetence are often unclear, however it can be predicted that the intimate interaction between the nervous and immune systems can potentially lead to toxicity.

Computer modelling as a tool for the exposure assessment of operators using faulty agricultural pesticide spraying equipment.

Background: Faulty but still operating agricultural pesticide sprayers may pose an unacceptable health risk for operators. The computerized models designed to calculate exposure and risk for pesticide sprayers used as an aid in the evaluation and further authorisation of plant protection products may be applied also to assess a health risk for operators when faulty sprayers are used.

Objective: To evaluate the impact of different exposure scenarios on the health risk for the operators using faulty agricultural spraying equipment by means of computer modelling.

Influence of chlorpyrifos on the profile of subpopulations of immunoactive cells and their phagocytic activity in an experimental in vivo model.

Many environmental factors, including pesticides, cause immunological system disorders by inducing changes in humoral and cellular response. They may stimulate or trigger immunological autoaggression, hypersensitivity and allergy, as well as lead to immunosuppression, thus increasing the incidence of infectious diseases and cancers. Such activity is also attributed to organophosphorus compounds used in agriculture as insecticides, and commonly in households as biocides.

[Toxicological evaluation of crop protection chemicals in the EU registration process].

Authorisation of crop protection chemicals prior to placing into the market is being regulated with standardized regulations in the European Community territory. The Member States are obliged to introduce all provisions constituting the base for the evaluation of protection chemicals and determining their safety for man and environment. The rules governing toxicological evaluation of plant protection products and their active substances have been discussed and the practical relevance of the harmonized provisions for the safety assessment of pesticides in the EU were also presented.

[Phenobarbital-induced hypermethylation of the p53 promoter region in the liver of Wistar rats].

Non-genotoxic carcinogens (NGCs)-induced changes of DNA methylation has been proposed as a mechanism of their toxicity, including carcinogenic action. The effect of phenobarbital (PB), a rodent liver carcinogen on the methylation level of the p53 promoter region in rat liver was studied. Changes in the methylation status of the p53 gene were correlated with changes in DNA synthesis, DNA methyltransferase (DNMTs) activity and liver weight.

[Effect of diclofop on the activity of some drug-metabolizing enzymes in the liver of male Wistar rats].

The study was designed to determine whether diclofop, introduced to environment as herbicide, would exert properties of chemical inducers of rat liver monooxygenase system related to CYP1A and CYP2B isozymes. For this purpose, the effect of diclofop on 7-etoxyresorufin O-dealkylase and p-nitroanisole O-demethylase activities specific for CYP1A as well as on CYP2B mediated 7-pentoxyresorufin O-dealkylase activity was studied in male Wistar rats. This biochemical method permits to determine whether tested compound belongs to one of two main types of chemical inducers.