[Features of eosinophilic pneumonia course in the outpatient setting].

Simple eosinophilic pneumonia (Luffler's syndrome) is combination of "volatile" infiltrates, independently passing during one month and detecting only in chest organs roentgenography; often pass symptomless. There is a mild eosinophilia in the blood. Acute eosinophilic pneumonia is an antipode of simple eosinophilic pneumonia, has a clinical course with acute respiratory failure, pulmonary destruction, high eosinophilia and favorable prognosis under conditions of treatment with glucocorticoids.

[Disorders of antioxidant defence and their correction in experimental di-isopropyl-phenyl-isocyanate intoxication].

Using preventively natural and artificial antioxidants in experiments on white rats enabled to assess role of lipids peroxidation in mechanisms of acute inhalation toxicity caused by 2,6-diisopropylphenylisocyanate. Correlation and regression analysis revealed differences in mechanisms underlying antioxidants effects.

[Prospects of the development of preventive toxicology in the 21st century].

The national toxicology has created considerable theoretical potential to enter XXI century. Significant experience is associated with introducing the novelties. However, some circumstances inhibit environmental protection from chemical disorder.

[The toxicological, hygienic and clinical aspects of the action of low levels of organic solvents].

The article presents experimental data showing that Average Shift Concentration (ASC) and Maximal Single Concentration (MSC) for some solvents (tetrachloromethane, tetrachloroethane, dimethylformamide, benzene) are expedient to be justified. Clinical and hygienic materials proved significant health parameters (nervous system, peripheral blood) and urine levels of main metabolites to depend on chlorbenzene and toluene concentrations influencing the workers. Having analyzed the results, the authors recommended following hygienic norms in the air of workplace: for chlorbenzene ASC--50 mg/cu m, MSC--100 mg/cu m; biologic MAC for urine 4-chlorcatechol--0.

[Hygienic aspects of the regulation of occupational chemicals].

Hygienic regulation of chemical hazards in the air of workplace has a 70-year history in this country. Now a definition "maximal allowable concentration in the air of workplace" needs to be more precise, and a list of MACs should be modified.

[Materials for the substantiation of the biological MAC of benzene].

Relatively great amount of benzene-originated phenol, the presence of a definite relationship between phenol amount in the urine and benzene content in the air indicate that it is reasonable to use a phenol sample as an exposure test. To determine the intensity of benzene exposure, data on phenol content in the urine of people working at some big-tonnage enterprises has been analyzed. On the basis of the national and foreign literature data on the correlation between the phenol urine concentration and the level of benzene exposure a regression equation was deduced, which has made it possible to calculate phenol content in the urine on the level of average working day benzene concentration adopted in the USSR.

[Use of quantitative chemical characteristics of phenol ethers in the prognostication of toxicity and MPEL in the air of work areas].

The contributors use the molecular orbital technique to present, with due account of the metabolism specificity, a quantitative description of the phenol ether inhalation toxicity and their reactivity calculated against the energy of the ether and OH- complex formation. Linear dependencies were identified between the acute and chronic action threshold, MAC and the quantum chemical values of the energy of formation. The dependencies were utilized for forecasting the toxicity and safe levels for 37 substances.

Application of toxico-kinetic criteria as a basis for toxicometric parameters.

In an experiment with single exposure to benzene and styrene at a level corresponding, to the threshold of harmful effect established by functional indices the intensity of metabolism was found to decrease. Toxico-kinetic characteristics of the substance in a single experiment permit us to prognosticate the risk of developing chronic intoxication. In comparison with indices characterizing general state of the organism, toxicokinetic indices enhance the reliability of toxicometric parameters used in determining Mac's for the air of the working area.

Intermittent exposure to toxic compounds in the working-zone atmosphere viewed from the aspect of hygienic standardization.

Four highly cumulative substances (carbon tetrachloride, 1,1,2,2-tetrachloroethane, benzene and dimethylformamide) were studied at two exposure levels under a monotonous and an intermittent exposure regimen in subacute experiments on rats. The biological effect produced by the intermittent concentrations as compared with the stable concentrations under time-weighted average concentrations depended both on the physiochemical properties and biological action of the poisons as well as on the exposure level. The intermittent concentration rises within certain limits (threefold as a rule) were injurious with some of the substances at a relatively high exposure level, but were not detrimental as compared with stable concentrations at a low exposure level.

Results obtained in short-term experiments and their application prospects in prognosticating threshold levels of chronic exposure to chemical compounds.

Joint studies carried out by toxicologists of CMEA countries have led to the development of new ways of approach to the problem of rapid establishment of toxicometric parameters and hygienic standards (TSEL, MAC) for the working-zone atmosphere. One of the most promising approaches is the rapid establishment of MAC from the threshold of acute specific effect. Upon this principle, methodical directives for determining MAC values for specifically active irritants were elaborated.

Development of methodological approaches to the determination of safe levels of activity of harmful substances in the air of the working environment.

1. An experiment study was carried out to substantiate fundamental approaches to the determination of shift-average and maximum instantaneous concentration of highly cumulative substances in the air of the working environment. 2.