Zoltán Adamis

Occupational exposure to organophosphorus insecticides and synthetic pyrethroid.

SummaryDermal and respiratory exposure to pirimiphosmethyl, dimethoate and permethrin were determined for applicators and operators in greenhouse tomato spraying operations. Dermal exposure is several times higher than the degree of respiratory exposure. Dermal exposure in terms of different parts of the body shows significant differences. For applicators the exposure of hands, arms and legs is the greatest, and the operators are the most exposed on their hands and to a small extent on legs. This fact should be taken into account when providing the workers with suitable protective clothing. The carefully selected technology of spraying also has great significance in decreasing the degree of exposure. Because of the chronic toxicity of dimethoate, all possible methods should be taken to reduce exposure.

In vivo pulmonary toxicity of cellulose in rats.

Cellulose after a single intratracheal dose (15 mg per animal) brought about fibrosing granulomatous alveobronchiolitis and an increase of IgA production in the bronchoalveolar lavage. Fibrosing alveolitis showed moderate progression as a function of time. With different morphological methods, injury of type I pneumocytes and the incomplete repair of type II pneumocytes were detected. The damage of the alveolar epithelium initiated and activated a series of processes that led to definite pulmonary alterations: pulmonary fibrosis leading to the disintegration of the alveolo‐capillary morphological functional unit.

In vitro and in vivo assessment of the pulmonary toxicity of cellulose

The lung‐damaging effect of intratracheally administered cellulose was studied by biochemical and histological methods. Cell count, protein, phospholipid, lactate dehydrogenase and acid phosphatase were determined in bronchoalveolar lavage fluid 1, 3 and 7 days after intratracheal instillation. Histological tests were performed after days 1, 3 and 30. In vitro, cellulose did not damage the macrophage cells. In vivo, interstitial oedema as well as the initial signs of inflammation could be detected in the lung after the first day. Inflammation after 1 week could be noted, partly interstitial and partly intra‐alveolar and intrabronchial. In the bronchoalveolar lavage fluid, protein, lactate dehydrogenase, acid phosphatase, phospholipid and cell count were enhanced after days 1 and 3. After 1 month, the developing bronchioalveolitis is fibrous in character. Contrary to the in vivo study, cellulose did not damage rat peritoneal macrophages.

Characterisation of lectin binding patterns of mouse bronchiolar and rat alveolar epithelial cells in culture.

Lung epithelial cell differentiation pathways remain unclear. This is due in part to the plasticity of these cells and the lack of markers which accurately reflect their differentiation status. The aim of this study was to determine if lectin binding properties are useful determinants of functional differentiation status in vitro. Mouse Clara cells were cultured for 5 days. During this time, no alteration in differentiation was evident by electron microscopy. No significant alteration in binding reactivity of Bauhinia purpurea (BPA), Maclura pomifera (MPA), Concanavalin A, Wheat germ or Helix pomatia lectins occurred in cultures compared with Clara cells in mouse lung tissue. In contrast, nitrotetrazolium blue reductase activity and CC10 expression declined in culture. Rat type II cells were cultured for 8 days. Between days 0 and 4, the number of type II cells identified by electron microscopy was constant at 70–80%, decreasing to 8% by day 6. In contrast, by day 4, only 42% cells retained alkaline phosphatase activity. BPA and MPA reactivity was altered at day 0 and day 4 respectively, compared with cells in situ. Therefore, the reactivity of lectins analysed here does not reflect functional differentiation status of cultured mouse Clara cells. However, BPA and MPA reactivity may be a sensitive indicator of alterations in rat type II cell differentiation in vitro.

Effects of various mineral dusts on macrophages in vitro

SummaryExperiments in vitro have been conducted to determine the effect of mineral dusts (quartz, bentonite, illite, kaolin, and coal) on rat peritoneal macrophages. The authors found a connection between the cytotoxic effect, measured by the in vitro TTC reduction of certain aluminium silicates (kaolin, illite, bentonite), and the degree of methylene blue and paraquat adsorption capacity. In the case of bentonite, the cytotoxic effect of the dust decreases with an inverse ratio with the increasing amount of paraquat adsorption. In the case of maximal paraquat adsorption the TTC-RA50 value changed such an extent in comparison with bentonite adsorbed no paraquat that characteristics of dusts with no harmful effect. It is assumed that in the in vitro cytotoxic effect of bentonite, those groups play a role, which participate in cation exchange.

Combined pulmonary toxicity of diethyldithiocarbamate and lead (II) oxide in rats

The pulmonary toxicity of sodium diethyldithiocarbamate and lead(II) oxide alone or in combination was studied in rats after a single intratracheal instillation. The lead content in the lungs and the whole blood was determined and it has been found that the clearance of lead from the lung was delayed by dithiocarbamate complex formation, which probably had a role in increased IgA levels in the bronchoalveolar fluid and the induction of local immune response. The combined exposure gave rise to calcium deposits in the lungs both extra‐ and intracellularly after 1 month of exposure. Both separate and combined exposure invoked permanent injury in membranes or dystrophic changes in the cytoplasm of pneumocytes, which may initiate and generate a series of events leading to fibrosing alveolitis.

EFFECTS OF SODIUM DIETHYLDITHIOCARBAMATE ON TYPE II PULMONARY EPITHELIAL CELLS IN VITRO

Dithiocarbamates (DDTC) are chemicals widely used in the form of pesticides, therapeutic and chelating agents, and scavengers. Since DDTC interfere with SH, Cu, and Zn enzymes due to chelating properties, it was of interest to clarify, in primary culture of type II alveolar pneumocytes, the effect of this compound upon enzymes of glutathione cycle, Cu, Zn-superoxide dismutase, and the membrane structure of cells. DDTC significantly inhibited the activity of superoxide dismutase and the activity of gamma-glutamyl transpeptidase, glutathione reductase, and alkaline phosphatase, whereas an increase in the activity of glutathione peroxidase was found. The membranes of pneumocytes type II were injured. Data show that DDTC adversely affected type II pneumocyte function and structure.

STUDY OF INFLAMMATORY RESPONSES TO CROCIDOLITE AND BASALT WOOL IN THE RAT LUNG

The subacute effects of crocidolite and basalt wool dusts were studied by means of biochemical, morphological, and histological methods 1 and 3 mo after intrabronchial instillation. The cell count, protein and phospholipid contents, and lactate dehydrogenase (LDH) activity were determined in the bronchoalveolar lavage (BAL). Both types of fibers induced a prolonged inflammatory reaction in the lung. All the parameters studied in the experimental groups were more markedly elevated after 3 mo. Relative to the control, the protein and LDH values were increased three- to fivefold, the phospholipid content twofold, and the number of free cells in the BAL exceeded the control level up to ninefold. The inflammatory responses to crocidolite and basalt wool in the lung did not differ significantly. In spite of this, basalt wool is recommended as an asbestos substitute, as the use of this man-made fiber may result in a significantly lower release of dust than that from crocidolite.

Effects of lead(II) nitrate and a dithiocarbamate fungicide on the rat lung

The pulmonary toxicity of two potential environmental pollutants was studied in rats 1, 7 and 30 days after a single intratracheal instillation of lead nitrate and Dithane M‐45 (mancoceb), either individually or in various combinations. The cell count, protein, phospholipids and lactate dehydrogenase level were determined in the bronchoalveolar lavage fluid, as were the protein, phospholipids and acid phosphatase contents in the lung tissue. Lead nitrate and Dithane M‐45 induced acute inflammation reactions with different features. The effects of mixtures of lead nitrate and Dithane M‐45 were found to be different from those of the individual components. Copyright

Evaluation of Dust Toxicity by Short-Term Methods

Examination of respirable dusts of workplaces in mines has aroused interest all over the world. Great efforts have been made to use the results of animal experiments for prognostical purposes.