Consequent stages of developing a multi-compartmental mechanistic model for chronically inhaled nanoparticles pulmonary retention.

The paper retraces the development of a mechanistic multicompartmental system model describing particle retention in lungs under chronic inhalation exposures. This model was first developed and experimentally tested for various conditions of exposure to polydisperse dusts of SiO or TiO. Later on it was successfully used as a basis for analyzing patterns in the retention of nanoparticles having different chemical compositions (FeO, SiO, NiO).

On the contribution of the phagocytosis and the solubilization to the iron oxide nanoparticles retention in and elimination from lungs under long-term inhalation exposure.

The aim of our study was to test a hypothesis according to which the pulmonary clearance vs. retention of metal oxide nanoparticles (NPs) is controlled not only by physiological mechanisms but also by their solubilization which in some cases may even prevail. Airborne Fe2O3 NPs with the mean diameter of 14±4nm produced by sparking from 99.

[Effectiveness of glutamate in the treatment of early manifestations of occupational fluorosis].

Efficiency of glutamic acid for therapy of early signs of occupational fluorosis was studied in workers engaged into cryolite production. The study proved that use of glutamic acid in occupational conditions prevents progressing of metabolic disorders. The results encourage recommendations to include glutamate into therapeutic and prophylactic nutrition of workers exposed to fluor compounds, into nutritive additions according to special recipe.

Development of a multicompartmental model of the kinetics of quartz dust in the pulmonary region of the lung during chronic inhalation exposure of rats.

A multicompartmental model for the kinetics of dust retention in the pulmonary region of the lung and in the tracheobronchial lymph nodes has been developed. The model reflects the following ideas concerning the basic features of this process: (1) penetration into the pulmonary interstitium and translocation to the lymph nodes are possible for non-phagocytized particles only; (2) these processes depend on the degree of damage to macrophages by dust and on the extent of compensatory enhancement in the recruitment of neutrophils taking part in the clearance of the pulmonary region free surface; (3) a certain proportion of initially penetrating particles is continuously returned to this surface together with recruited pulmonary macrophages. The model ensures a satisfactory approximation to experimental data on the retention of quartz in the lung and lymph nodes during long term inhalation exposure, and simulation of the kinetic effects associated with both the damage to and the protection of the macrophagal clearance mechanism.

[The toxicokinetics of low-solubility substances (exemplified by 2 boron compounds)].

Multichamber toxicokinetic model studies of the resorption, distribution and excretion properties of poorly soluble substances in subchronic action of suspensions administered intragastrically can be the first step in prognosing the toxicokinetic properties of the inhaled aerosols of the substances mostly discharged from the respiratory into the gastrointestinal tract (GIT). The generally accepted quantitative characteristics of the particles' deposition and translocation into GIT can provide a further application of the model for a mathematical description of a prolonged inhalational exposure to some substances. This technique was tested with the boron compounds characterized by low solubility and revealed a good correlation between the prognosed and actual deposits of the substance in the organ and excretions.

[A multi-chamber model of quartz dust kinetics in the pulmonary region during chronic inhalation exposure in rats].

The contributors propose a multichamber model for the assessment of dust particles' concentration, elimination and translocation in deep pulmonary zones. The choice of the model structure is dominated by the following criteria: that dust penetration into the interstitial pulmonary tissues and its translocation to the lymph nodes can be performed by non-phagocytized particle only; that these processes depend on the degree of dust-induced lesions in the macrophages and the growth of compensating neutrophilic phagocytosis; that part of the penetrating particles would continuously return to the free surface of the pulmonary zone together with the mobilized interstitial lung macrophages. The model adequately corresponds to the experimental data obtained in prolonged inhalation experiments, and imitates the kinetic effects related to severe damages and protection of the pulmonary clearance macrophage mechanisms.

[Role of serum factors in regulating interferon production].

A relationship between the level of interferon production, intensity of lipid peroxidation, the activity of proteolytic enzymes, and the age of the blood serum donor was established on a model of peritoneal exudate cells from mice of different ages. Trypsin was found to inhibit interferon production levels in the same way as did the serum of newborn mice. Introduction of protease inhibitor increased interferon production considerably.