编号 4 (2017)

A comparative analysis of influence of fentanyl, dexmedetomidine and their combination on physical activity tolerance, electrocardiogram indexes and integral tolerance rates (therapeutic indices range) was conducted on an experimental model of cardiac failure induced by daily subcutaneous injections of 0.4 mg/kg adrenaline hydrochloride over 7 days. The findings were also confirmed by histomorphologic validation. In a suggested model of impaired cardial function, the analgesic activity and toxicity of fentanyl, dexmedetomidine and their combination were assessed in comparison with intact animals. It was shown that on the background of cardiac pathology, 13 to 25% decrease of average lethal doses was observed for each of the drugs under consideration. At the same time when drugs were administered in combination, an average aanalgetic dose did not change unlike single-drug analgesia.

Experimental studies of toxicity and hazard assessment of a mixture of С1-С5 saturated hydrocarbons as pollutants of atmospheric air were performed. It was shown that the mixture exhibits a low toxicity at a single exposure and does not irritate skin and eye mucous membranes. The Limac of the С1-С5 mixture was set at 25300 and 3100 mg/ m3 by the resorptive and reflex effects respectively. After 90-day chronic continuous exposure to the mixture, symptoms of chronic intoxication, specifically functional disorders in the nervous, cardiovascular, and respiratory systems and in biochemical processes, were revealed. The threshold concentration of the mixture was estimated at 255.7 mg/m3 . The experimental results were used to substantiate hygiene regulatory standards (MAC average day dose, and MAC maximum one-time dose) and hazard class for the mixture of С1-С5 saturated hydrocarbons in the atmospheric air of residential areas.

The paper presents an overview of the main methodological approaches in experimental standardization of odorants (or mixtures of odorants) in the ambient air according to «obsessive» odor inadmissibility as a limiting criterion for justification of Maximum allowable concentration (MAC maximum one time dose) . It is shown that the developed procedure of establishing a permissible content of those substances is based on estimating the relationship «concentration – odor sensation probability of different intensity» (olfactory-odorimetry), using a common scoring of smell intensity and modern olfactometry equipment. Justified normative values are harmonized with international criteria for air quality including epidemiological studies-based levels established for odors with various qualitative characteristics. Their implementation will ensure the protection of the population from «obsessive» odor.

The use of nanoparticles covers new spheres of production every year. Their release into the environment is possible at any stage of their lifespan: from the manufacturing process to the utilization in the final product; therefore potential risks they pose for various environmental objects should be evaluated. The purpose of this work was to assess the effect of technogenic nanoparticles on Chlorella vulgaris growth and photosynthetic activity. Toxic properties of three types of nanoparticles TiO2 with a size of 100 to 190 nm, SiO2 with dimensions of 10-15 nm and 100-120 nm have been studied. Chlorella vulgaris Beijer alga was used as test organism. The evaluation of nanoparticles toxicity was based on changes in the relative delayed fluorescence index (RDFI), which characterizes the photosynthetic activity of microalgae. The effect on the growth of the test culture was determined from the optical density (OD) of the algal suspension. It was found that the TiO2 nanoparticles slightly reduced the growth and activity of the cell photosynthetic apparatus. Large particles of SiO2 proved to be more toxic than smaller ones. For nanoparticles of 100-120 nm size , the EC50 value according to the OD index was 8 mg/dm3, while the particles measuring 10-15 nm did not show a significant effect on the growth of the culture. Large SiO2 particles also appeared more toxic than small particles, judging by RDFI parameter.