No 6 (2023)

Introduction. Human production activities (metallurgical, mining, electronics production and processing, batteries) are related to air pollution of the working area and the environments of complex composition aerosols. Among the aerosol components, ultrathin particles of the nanometer range (including metal nano-oxides) are considered to be the most dangerous. Due to their prevalence, study to assess the cytotoxicity of metal oxide nanoparticles are relevant.

Material and methods. CuO, PbO, CdO, Fe₂O₃, NiO nanoparticle (NP) suspension were obtained by laser ablation. The study was done on white outbred female rats. A single intratracheal instillation of different chemical NPs was performed (in dose 0.5 mg/animal); control animals received a similar amount of deionized water. A day after the NP instillation bronchoalveolar lavage (BAL) was carried out with the subsequent assessment of its cytological indices.

Results. The cytotoxic action of the studied NPs, based on the cytological indices of the BAL fluid, is changed as follows (from greater to lesser): CuO NP > CdO NP > PbO NP > NiO NP > Fe₂O₃ NP.

Limitations. Such physical characteristics of nanoparticles as solubility in water and biological fluids, charge, adsorption capacity, resistance to aggregation, hydrophobicity, adhesion to surfaces, and the ability to generate free radicals have not been studied. Extrapolation of data from rodents to humans shall be done with caution, since cytotoxicity has been characterized only based on the main cellular parameters.

Conclusion. Bronchoalveolar lavage cytology can be used as an effective screening method for the cytotoxic effect of NPs.

Compliance with ethical standards. The animal study protocols were approved by the Institutional Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers (Protocol No. 2 of April 20, 2020).

Contribution of the authors:
Sutunkova M.P., Minigalieva I.A., Privalova L.I. — the concept and design of the study, editing;
Klinova S.V., Ryabova Yu.V. — conducting a study, the collection and processing of the material, writing text, editing;
Tazhigulova A.V. — conducting a study, the collection and processing of the material, editing.
All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.

Acknowledgment. Authors express their gratitude to the team of the Ural Center for Collective Use “Modern Nanotechnologies” of the Ural Federal University named after the first President of Russia B.N. Yeltsin and personally to the director of the Ural Center for Collective Use “Modern Nanotechnologies”, professor, doctor of physical and mathematical sciences Vladimir Yakovlevich Shur, for the synthesis of suspensions, studied nanoparticles of a given characteristic on the basis of the “Modern Nanotechnologies” center.

Conflict of interests. The authors declare no conflict of interests.

Funding. The study had no sponsorship.

Date of receipt: May 18, 2023 / Date of acceptance for printing: December 3, 2023 / Date of publication: December 29, 2023

Introduction. In the event of fires in residential premises in which nitrogen-containing thermal insulation materials (foam rubber, polyisocyanurate foam) are used, the victims will be exposed to toxic thermal degradation products. Data on long-term disorders caused by intoxication by thermal degradation products of these materials could not be found in the available literature.

The aim of the study was to assess the toxicity of the products of thermal oxidative degradation of nitrogen-containing thermal insulation materials, both in the early and long-term post-intoxication period.

Material and methods. Static inhalation intoxication of rats with products of thermooxidative destruction of polyfoam and polyisocyanurate foam (at a concentration of 0,8HLC₅₀) was simulated. The concentration of carboxyhemoglobin in the blood of rats, indicators of vital functions were determined immediately before and on days 1, 7 and 28 after exposure. To assess learning disabilities in rats, a conditioned reflex of active avoidance by swimming was developed. To assess spatial memory in rats, the method of developing and reproducing the conditioned reflex of searching for food was used.

Results and discussion. The intoxication of rats with products of thermooxidative destruction of the studied materials of moderate severity was simulated. Violations of the functions of the respiratory and cardiovascular system of rats in the early (7 days) and long-term (28 days) post-intoxication period were not detected. In the long-term (28 days) post-intoxication period, an increase in the duration of the latent period of active avoidance by swimming of rats was determined (compared with the control), an increase in the number of spatial memory errors in rats and the time of testing (compared with the control) was revealed.

Limitation of the study. Limitations are due to the methodology of the research being conducted. A quantitative analysis of only some gaseous products of thermal oxidative destruction was perfomed.

Conclusion. It was found that intoxication of rats with products of thermooxidative destruction of foam rubber and foam polyiysocyanurate (at a concentration of 0,8HLC₅₀) led to impaired learning and spatial memory of rats in the long-term post-intoxication period.

Compliance with ethical standards. the study was approved by the local ethics committee of the The S.M. Kirov Military Medical. The work was guided by the requirements of legal acts on the procedure for experimental work using animals, including humane treatment of them.

Conflict of interest. The author declare no conflict of interest.

Acknowledgment. The study had no sponsorship.

Date of receipt: May 3, 2023 / Date of acceptance for printing: December 3, 2023 / Date of publication: December 29, 2023

Introduction. One of the direct methods of assessing the impact of contaminants on public health is the use of biological markers that allow determining the presence of a substance or its metabolite in human biological tissues and the dose received from all sources of this substance.

The purpose of this study was to determine the dependence of arsenic content in biological samples (hair)
of exposed residents on the level of its content in drinking water and to substantiate the effectiveness of the use of this biomarker in the conditions of a hydrogeochemical province in the Republic of Dagestan.

Material and methods. During this research the arsenic content in the hair of the exposed residents was measured with further comparison of the data obtained with its content in drinking groundwater. To determine the arsenic content in the hair of the exposed residents, an atomic absorption method was used with preliminary preparation of biosubstrate samples. Socio-demographic data were obtained from a questionnaire. Statistical data processing was carried out using Microsoft Excel.

Results. In the course of this study, a correlation was revealed between the arsenic content in the hair of the exposed residents and its content in the drinking water consumed, and a direct proportional relationship between these values was also revealed. Thus, with an increase in the concentration of arsenic in water by
0.1 mg/l, the arsenic content in the hair increases by 0.14 mkg/g. So, using of the hair of exposed residents as a biomarker of long-term exposure is recommended to small doses of arsenic in a biogeochemical province.

limitation of the study is the small sample size. However, this does not prevent the assessment of the effectiveness of using hair as a biomarker of arsenic exposure and preliminary conclusions for subsequent in-depth analysis of biomonitoring in the conditions of biogeochemical provinces.

Conclusion. As a rule, the content of natural toxic elements is characterized by trace amounts in the conditions of biogeochemical provinces. Biomonitoring will reveal the level of stress on the body and timely apply preventive methods before the clinical signs of intoxication are revealed.

Compliance with ethical standards. The study does not require the submission of a biomedical ethics committee opinion or other documents.

Authors contribution:
Abdulmutalimova T.O. — setting the purpose of the study, concept and design of the study, statistical data processing, text writing, editing;
Ramazanov O.M. — conducting field work, collecting and processing material, conducting chemical analysis, writing the text.
All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.

Conflict of interest. The authors declare no conflict of interest.

Funding. The study had no sponsorship.

Date of receipt: October 23, 2023 / Date of acceptance for printing: December 3, 2023 / Date of publication: December 29, 2023

Introduction. Mathematical models are widely applicable in conducting toxicological studies and can be used to fill gaps that arise in the assessment of chemical safety. Most of the attention is paid to the study of algorithms for constructing models, rather than approaches to choosing the most informative features.

The purpose of this study is to highlight aspects of the problem of choosing useful variables during mathematical modeling.

Material and methods. SMILES and molecular descriptors for organothiophosphates were generated in the interactive Google Colaboratory environment based on the program code using the RDKit, Mordred software. Using the tools of the scikit-learn Ver. 1.2.2 library, features were selected by filtering and by recursive feature exclusion. The values of acute oral toxicity parameters were taken from official information sources about chemicals. The obtained models are subjected to an internal validation procedure to evaluate the performance of the models.

Results. It should be noted that models where recursive exclusion of features was used have better characteristics than models based on descriptors selected by the filtering method. In particular, the acute toxicity prediction model for organothiophosphates based on the decision tree method with recursive exclusion of features has a high coefficient of determination (R²=0,91713), a relatively small root-mean-square error (RMSE= 0,35099), as well as high values of the cross-validation coefficient of determination (Q²LOO= 0,79756).

Limitations. The results obtained can be used only in predicting the toxicity of the specified group of chemicals with a similar mechanism of action.

Conclusion. The use of mathematical modeling is a promising tool for assessing the toxicity of chemicals, which has a number of features: on the one hand, it is a quick and convenient resource for screening the toxicity of substances, on the other hand, the model needs to be trained based not only on reliable research data, but also to carry out a qualitative selection procedure for signs that make a significant contribution to the functioning of the prognostic model.

Compliance with ethical standards. The study does not require the submission of the conclusion of the Biomedical ethics committee or other documents.

Conflict of interest. Author declare no conflict of interest.

Funding. The study had no sponsorship.

Date of receipt: September 21, 2023 / Date of acceptance for printing: December 3, 2023 / Date of publication: December 29, 202