Hygiene and Sanitation

Introduction. Microplastics pose a significant health threat due to their toxicity and capacity for bioaccumulation. Although studies have confirmed their detrimental effects on biological systems, the mechanisms governing particle accumulation and particle distributions have not been sufficiently studied. The aim of our study was to develop and experimentally validate a semi-quantitative method to assess these processes on the base of investigation of the distribution of plastic microparticles in the organism under acute in vivo experimental conditions using a semi-quantitative method.Materials and methods. Twelve female Wistar rats were divided into four groups. Animals received intracardiac injections of polystyrene microparticle suspensions (100, 500, and 1000 nm in diameter) or physiological saline solution. The accumulation of microparticles in six organs was evaluated using a semi-quantitative scoring method based on fluorescence microscopy and a rank-scale assessment. Data were analyzed using bootstrap methods with Holm–Bonferroni corrections, and differences were considered significant at p < 0.05.Results. Following intracardiac administration, polystyrene microparticles measuring 100, 500, and 1000 nm were detected in the liver, kidneys, and lungs. They localized primarily in hepatic triads, the renal cortex, and the acinar regions and alveolar ducts of the lungs. The highest levels were observed upon administration of 1000-nm particles. Semi-quantitative analysis revealed liver and lung tissues to accumulate significantly more microparticles of the 1000-nm in size, while the kidneys showed greater accumulation of the 100-nm particles.Limitations. This study was limited to examining the distribution of three microparticle size groups in a single animal model (laboratory rats, only 3 animals in each group) under acute toxicological conditions.Conclusion. The intensity and abundance of fluorescent tissue elements depend on particle size and may be associated with the formation of microparticle conglomerates. While the semi-quantitative method allowed identifying certain distribution patterns, further research involving quantitative approaches is required to enhance the accuracy and specificity of these findings.Compliance with ethical standards. All experiments in this study were conducted in accordance with European Convention standards for the protection of vertebrate animals used for research and other scientific purposes. The study protocol was approved by the local ethics committee (Approval No. 01-10 from October 9, 2024).Contribution: Ahmadeev A.R. – conducting the experiment, data collection and processing, writing the text, preparing figures; Ryabova Yu.V. – research concept and design, writing the text; Karimov D.O. – research concept and design, scientific editing of the text; Khusnutdinova N.Yu. – conducting the experiment; Kudoyarov E.R. – data collection and processing, writing the text; Valova Ya.V. – research concept and design, data collection and processing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final versionConflict of interest. The authors declare no conflict of interest.Funding. The study was carried out within the framework of the sectoral research program of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing for 2021–2025.Received: December 23, 2024 / Revised: January 15, 2025 / Accepted: March 26, 2025 / Published: June 27, 2025

Introduction. The study is devoted to the investigation of the effect of chronic stress on the toxic effect of paracetamol on the liver in rats. Paracetamol, widely used as an analgesic and antipyretic, can cause hepatotoxicity associated with the formation of reactive oxygen species and the development of oxidative stress when overdosed. Antioxidant mechanisms of the body’s defense include key genes such as Hmox1, Sod1, and Nqo1, which regulate the redox balance. Chronic stress reduces glutathione levels, which increases the vulnerability of the liver to toxic effects. The purpose of the work is to assess the toxicity of paracetamol in rats under the influence of chronic stress to develop new preventive approaches.Materials and methods. The experiment involved four groups of white outbred rats (6 males and 6 females), which were administered paracetamol (1000 mg/kg) and modelled chronic stress. Results. Morphological, biochemical, and genetic analyses were performed, and the liver weight coefficient was detected. In males, the liver weight coefficient varied: the minimum value (25.02) was recorded in the Stress group, the maximum (32.27) in the control group (p=0.001). In females in the «Stress» group, it was 34.77, which is lower compared to the «Paracetamol» (39.21; p=0.017) and «Paracetamol+Stress» (39.24; p=0.026) groups. Histomorphological analysis revealed signs of necrosis and inflammation with combined exposure. Genetic analysis showed an increase in Sod1 gene expression in males in the «Stress» group (p=0.001) and the highest Nqo1 level in the group with combined exposure to factors. Biochemical changes included decreased AST and ALT levels under stress and paracetamol.Limitations. For the experiment, laboratory animals of one biological species were used, and the toxicant was used in the only one concentration.Conclusion. The obtained results highlight the need for further study of the interaction of chronic stress and toxic factors for the development of preventive measures.Compliance with ethical standards. The study protocol was approved by the local ethics committee of the Ufa Research Institute of Occupational Medicine and Human Ecology (Approval No. 01-02 from 08.02.2024). Throughout the study, the animals were kept in standard conditions with 12-hour artificial lighting during the daytime, a relatively constant level of humidity (30–70%) and an air temperature of 20–25 °C. All animal manipulations were carried out in strict compliance with the rules prescribed in the basic regulatory documents, including the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (Strasbourg, 1986) and the Helsinki Declaration on the Humane Treatment of Animals.Contribution: Gizatullina A.A. – study concept and design, collection and processing of material, statistical processing, writing the text; Karimov D.O. – study concept and design, statistical processing; Yakupova T.G., Ryabova Yu.V., Kudoyarov E.R., Khusnutdinova N.Yu. – collection and processing of material; Valova Ya.V. – collection and processing of material, statistical processing; Smolyankin D.A. – editing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. Industry research program of the Federal Service for Supervision in Protection of the Rights of Consumer and Man Wellbeing (Rospotrebnadzor) for 2021–2025 “Scientific substantiation of the national system for ensuring sanitary and epidemiological welfare, managing health risks and improving the quality of life of the population of Russia”, on the topic: 6.9.1.2 “Study of the impact of chemical production factors under conditions of chronic stress” No. NIOKTR I124021200153-3.Received: January 30, 2025 / Revised: March 5, 2025 / Accepted: March 26, 2025 / Published: June 27, 2025

The number of registered chemicals has doubled over the past seven years to 200 million compounds. Currently, the development of alternative research methods is becoming increasingly important. The methods of cross-reading and machine learning are of the greatest interest to researchers.The purpose of the study is to conduct a comparative analysis of read-across and machine learning methods used in predicting the toxicity of chemicals.A search was conducted for regulatory legal acts on two information and legal portals – ConsultantPlus and Garant.ru. The search for scientific literature was conducted using the PubMed database, the Cyberleninka scientific electronic library and the eLIBRARY electronic library using keywords such as "read-across", "toxicity prediction", "machine learning", and their analogues in Russian. The reports in Russian and English for the last 25 years have been selected, taking into account the inclusion and exclusion criteria. The conducted review showed the multidirectional application of read-across and machine learning in predicting the toxicity of chemicals. Despite the fact that there is a number of limitations to the use of these methods, a number of studies have demonstrated sufficient reliability and accuracy of their use. The combined use of read-across and machine learning will allow more effective predicting of chemical toxicity.Conclusion. The conducted review showed the multidirectional application of read-across and machine learning in predicting the toxicity of chemicals. Despite the fact that there is a number of limitations to the use of these methods, a number of studies have demonstrated sufficient reliability and accuracy of their use. The combined use of read-across and machine learning will allow more effective predicting the chemical toxicity.Contribution: Guseva E.A. – research concept and design, material collection and data processing, text writing; Nikolayeva N.I. – editing; Savranets E.V., Zhantlisova D.M. – material collection and data processing; Onishchenko G.G. – editing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. The study had no sponsorship.Received: January 15, 2025 / Accepted: March 26, 2025 / Published: June 27, 2025

The war set the primary tasks of preventing epidemics and strengthening the rear for health workers, including sanitary doctors and epidemiologists. The main areas of this work were provision the army with uniforms; creating means of immunoprophylaxis of infectious diseases; developing and improving disinfectants, conducting disinfection, disinsection, and deratization; air defense and anti-chemical defense, equipping bomb and gas shelters; protecting public utilities and food products; managing sanitary supervision of the movement of defense industry enterprises to the rear, and conducting sanitary measures in deoccypied territories.During the Great Patriotic War, the activities of the Erisman Central Research Sanitary Institute of the People’s Commissariat of Health of the RSFSR (now the Federal Scientific Center of Hygiene named after F.F. Erisman of the Federal Service for Supervision in Protection of the Rights of Consumer and Man Wellbeing (Rospotrebnadzor) were aimed at ensuring the sanitary wellbeing of the front and the rear. The Department of Occupational Hygiene, created in 1942 at the Erisman Central Research Sanitary Institute, carried out research aimed at maintaining the health of workers in defense industry enterprises. One of the important areas of the Institute’s activities during the war years was the development of the school department. In the conditions of evacuation and the changing educational process, it was necessary to adapt the educational programs to the requirements of wartime. The Institute provided assistance to areas liberated from occupation. Research staff gave lectures and talks, instructed workers on the restoration of destroyed villages, cleaning, and water supply. The Institute supplied equipment, apparatus, and reagents to sanitary and bacteriological. During the Great Patriotic War, the institute’s employees selflessly gave all their strength, knowledge and experience at the front and in the rear, bringing the Victory closer. According to archival data, eighty employees of the Erisman Central Research Sanitary Institute participated in the Great Patriotic War. The memory of laboratories of the number of cities anfall the employees who went through the trials of war and the difficulties of post-war reconstruction of the country is carefully preserved by the Federal Scientific Center of Hygiene named after F.F. Erisman of the Rospotrebnadzor.Contribution: Gavrilenko O.L. – collection of literature data, writing the text, editing, responsibility for the integrity of all parts of the article, approval of the final version of the article; Sidelnikova E.V. – collection of literature data, writing the text, editing; Karibzhanyants V.V. – collection of literature data. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. The study had no sponsorship.Received: March 11, 2025 / Accepted: March 26 / Published: June 27, 202