Introduction. Dengue fever remains endemic in tropical urban areas, but the sociodemographic determinants of larval control behaviours are poorly understood, particularly in delta cities like Banjarmasin, Indonesia. This study examined how education level and age influence Aedes aegypti larval control practices in household water containers. The objective was to assess the socio-demographic determinants of behaviors against larvae and their relationship with Aedes aegypti infection.

Materials and methods. A cross-sectional study of 236 households (March – November 2024) used structured interviews and direct inspections. Data were analyzed using Chi-square tests and binary logistic regression.

Results. Higher education predicted proper drainage (OR=2.44, 95% CI: 1.33–4.49, p=0.006), while younger age was associated with frequent inspections (OR=1.91, 95% CI: 1.12–3.26, p=0.017). Larvicide use reduced larval presence by 54% (OR=0.46, p=0.004).

Limitations. The cross-sectional design limits the ability to establish causal relationships.

Conclusion. Targeted interventions addressing education and age-specific barriers could enhance urban dengue fever control programs.

Compliance with ethical standards. Health Research Ethics Committee of the National Research and Innovation Agency, with approval number No: 076/KE.03/SK/04/2024

Contribution:
Ridha M.R. – concept of the study, carried out the experimental research in the field, summarized the research results, writing text;
Yahya Y. – made draft the research proposal, performed the experimental research in the field, and created the research results;
Hidayah N., Indriyati L., Juhairiyah J. – helped generate the research results, editing;
Agustina N. – assisted in field data collection and summarized the research results;
Budidarma A. – analyzed the research results and contributed to visualization.
All authors are responsible for the integrity of all parts of the manuscript and the approval of the final version of the article.

Acknowledgment. The author would like to thank the leadership and enumerator team from the Kalimantan Leading Polytechnic: PoLanKa, who assisted with the use of the laboratory and helped collect data in the field.

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

Funding. National Research and Innovation Agency (BRIN), Republic of Indonesia.

Received: August 13, 2025 / Accepted: December 2, 2025 / Published: April 17, 2026

Introduction. The increasing intensity of environmental pollution dictates the need to monitor the content of priority pollutants in agricultural products and environmental components, since exposure to concentrations that do not exceed established hygienic standards can manifest itself at the population level in the form of increased morbidity.

Aim of the study – study of the possible relationship between the levels of certain pollutants (OCPs, surfactants) in soil, agricultural products of plant origin and the health of the population to assess the impact of agriculture on it.

Materials and methods. The studies were conducted in the Vayots Dzor region of the Republic of Armenia, which is characterized by the lowest values ​​of gross agricultural output (2.3%). Soil (n = 47) and agricultural plant samples (n = 55) were collected to determine the content of certain organochlorine pesticides (OCPs) – γ-HCH, 4,4-DDT, 4,4-DDE, 4,4-DDD by the GLC method (Perkin-Elmer F-17, UK), their total content, and the concentrations of anionic synthetic surfactants (ASAS) by the spectrophotometric method (SF-26) (2019–2021). The phytotoxic and genotoxic activity of soils, as well as the incidence rates of diseases of the digestive system, were studied.

Results. OCPs were detected in soil and agricultural product samples with varying frequencies and levels, without exceeding hygienic standards. OCP levels in agricultural products were significantly lower than in soil. Concentrations of antiseptic surfactants, at normal levels in surface water, were higher than the hygienic standard in all soil samples (by 2–3.5 times), which may be due to migration and transformation patterns in this ecosystem. A study of the genotoxic activity of soil samples revealed no abnormalities. An analysis of the dynamic pattern of gastrointestinal diseases and their individual nosological forms showed no upward trends.

Limitations. The presented results are limited to a study of soil and agricultural produce contamination levels with certain priority compounds, the incidence of gastrointestinal diseases, and the possible contribution of agriculture to the identified situation in one region of Armenia.

Conclusion. The levels of the studied contaminants in soil and agricultural produce did not exceed hygienic standards. Nor changes in indicators of the soil genotoxic activity neither upward trends in population prevalence were observed. The environmental mutagenic status and population health in Vayots Dzor Marz, a well-known area for active recreation and tourism, remain stable.

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

Contribution:
Tadevosyan N.S. – the concept and design of the study, statistical processing, analysis and interpretation of results, text writing, the final design and editing, writing and approval of the final version of the article, responsibility for the integrity of all parts of the manuscript;
Poghosyan S.B. – the concept and design of the study, search for information, laboratory research, data processing, interpretation of results, text writing;
Muradyan S.A. – the concept and design of the study, search for information, material collection and data processing, laboratory research, interpretation of results, text writing;
Khachatryan B.G. – the concept and design of the study, search for information, material collection and data processing, laboratory research, interpretation of results, text writing;
Kirakosyan G.V. – material collection and data processing, search for information, text writing;
Ter-Zaqaryan S.H. – laboratory research, data processing;
Guloyan H.A. – sample analysis and data processing;
Babayan T.L. – material collection.

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

Funding. The study had no sponsorship. The work was carried out within the framework of funds allocated to Yerevan State Medical University named after M. Heratsi for the implementation of research work.

Received: June 2, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. The presence of odours in the atmospheric air constitutes a significant hygienic and social challenge for the population of urbanized industrial centers. Along with the risk of chemical toxication, olfactory stimuli act as a factor of prolonged stress, adversely affecting the psycho-emotional state and somatic health of the population, as well as provoking forced changes in daily behavior. The study of behavioral responses to olfactory discomfort is important for assessing the quality of life and developing targeted preventive measures.

The aim of the study. Systematization and analysis of population behavioral responses to the presence of unpleasant odours from industrial facilities in the air and study of the dependence of these responses on perception parameters (regularity of occurrence, odour intensity, and level of annoyance).

Materials and methods. The initial dataset was generated during a 2022 survey (Glazov, seven hundred nineteen respondents). Questions covered characteristics related to odour perception (frequency, intensity, degree of annoyance) and measures taken by residents when facing environmental problems. To identify groups of respondents with similar behavioral patterns, cluster analysis (k-means) was applied.

Results. Three behavioral patterns of response to olfactory annoyance were identified. The group with an active position (16.4% of respondents), characterized by submitting appeals to regulatory authorities, demonstrated the highest level of odour annoyance (5.33 out of 10), reported somatic and emotional symptoms more frequently, and had a higher prevalence of chronic diseases, predominantly of the respiratory and allergic profile. Participants with passive strategies — adaptation (42.8%) and avoidance (39.4%) — rated the level of annoyance significantly lower (4.63 and 4.43 points). Representatives of the active group significantly more often characterized the quality of the living environment at the place of residence as unfavorable and took into account the potential impact of pollutants when choosing places for recreation.

Limitations. The main limitation relates to the correlation character of the study, and the lack of accounting for other stress factors (e.g., noise), which may exert combined effects with odours.

Conclusion. The relationship was revealed between the intensity of odour annoyance and the strategies of population behavioral response, which emphasizes the need to account for subjective and behavioral indicators when conducting a hygienic assessment of atmospheric air pollution.

Compliance with ethical standards. The study was approved at a meeting of the Local Ethical Committee of the Centre for Strategic Planning of the Federal medical biological agency of Russia (protocol No. 01/10/21 dated 10/25/2021).

Contributions:
Goshin M.E. – study concept and design, data collection and processing, statistical analysis, data interpretation, and writing;
Budarina O.V. – study concept, results interpretation, and writing.
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 that there is no conflict of interest.

Funding. The study was carried out within the framework of state task No.1025061000007-6-3.3.5.

Received: November 10, 2025 / Revised: March 6, 2026 / Accepted: October 15, 2025 / Published: April 17, 2026

This study describes the results of a sanitary and epidemiological assessment of soil quality in the constituent entities of the Russian Federation (RF), based on the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) monitoring over the past 10 years, as a potential risk factor for harm to public health. A comparative dynamic analysis of soil samples for sanitary-chemical, microbiological, parasitological, and entomological indicators in the constituent entities of the RF is presented. Monitoring results from 2015 to 2024, containing information on more than 2 million soil samples, are analyzed. The obtained results are compared with the results of scientific literature and analyzed. The information was obtained through the analysis of domestic and foreign information sources – Scopus, Web of Science, PubMed, RSCI, etc.

Over the specified period, a positive trend was shown to be observed in the reduction in the number of samples with unsatisfactory indicators. Significant improvements are noted for sanitary-chemical and parasitological indicators. However, from 2021 to 2024, an increase was observed in the proportion of samples failing to meet to microbiological criteria, as well as those with residual contamination by persistent organic pollutants such as dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH).

The data analysis demonstrates the need to strengthen monitoring for soil microbiological parameters, which allow assessing their sanitary condition, and the content of persistent organic pollutants in soils. Soil, by absorbing these pollutants, acts as a long-term reservoir for pollutants. Under current conditions, all of the above is a strategic necessity for ensuring the sanitary and epidemiological well-being of the population, food security, and the sustainable development of populated areas.

Contributions:
Sinitskaya T.A. – editing;
Pletenev P.A. – study concept and design, literature collection and analysis, writing, editing;
Bukhonov A.V. – literature collection and analysis, 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: November 28, 2025 / Accepted: March 24, 2025 / Published: April 17, 2026

Introduction. Exposure to extreme occupational factors is associated with deterioration of employees’ physical and mental health, leading to reduced quality of life indicators. Professionals in high-risk occupations are subject to more stringent requirements compared to workers in other fields, including level of occupational training, mental, somatic health status, and personal qualities.

Materials and methods. Health-related quality of life was assessed using the SF-36 questionnaire in professionals with extreme work conditions and employees with standard occupational environments.

Results. Quality of life (QoL) significantly differed between male groups with extreme and non-extreme working conditions across three physical component scales (PF, RP, BP) and two mental component scales (VT, SF). Emergency service workers (EMERCOM) reported higher self-assessed QoL on scales measuring physical functioning compared to their counterparts. However, their daily activities were more limited by pain than those of emergency dispatch staff (EDDS). EMERCOM personnel rated their vitality and social functioning satisfaction significantly higher than dispatchers. Among female workers, QoL indicators revealed differences across five parameters between extreme and non-extreme occupational groups. Disaster medicine nurses showed significantly lower QoL scores than hospital inpatient nurses on both physical (PF, RP) and mental (VT, SF) component scales. Interestingly, their daily activities were less limited by pain (BP) compared to their hospital-based colleagues.

Limitations. The research was limited to male and female professionals in extreme occupations and workers with standard occupational conditions, all belonging to the first period of adulthood (early adulthood), with permanent residence in Khanty-Mansi autonomous Okrug – Yugra.

Conclusion. The predominant quality of life components were psychological dimension scales: mental health for EMERCOM personnel, vitality for EDDS dispatchers, and social functioning for disaster medicine nurses. In the hospital nurse group, the primary QoL component was general health - a criterion belonging to the physical dimension.

Compliance with ethical standards. The study was approved by the Local Ethics Committee of Nizhnevartovsk State University (Protocol No. 1, dated September 12, 2022) and conducted in accordance with the generally accepted scientific principles of the World Medical Association’s Helsinki Declaration (2013 version).

Contribution:
Pogonysheva I.A., Shalamova E.Yu. – concept and design of the study, text writing, editing;
Ragozin O.N. – factor analysis of research results;
Pogonyshev D.A. – data processing, editing;
Arkhipov N.V. – collection of material.
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: June 25, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Occupational burnout is a widespread condition characterized by chronic emotional and physical exhaustion, most commonly observed among professionals engaged in intensive interpersonal work. Contemporary prevention strategies are primarily based on psychological interventions, which require specialist involvement and are typically implemented in group settings. This limits their accessibility and individualization. Physiological approaches, particularly the stimulation of the diving reflex, may serve as an effective alternative for personalized use.

Aim. To evaluate the effectiveness of the diving reflex stimulation technique as the individual physiological method of the occupational burnout influencing.

Materials and Methods. The study was conducted on volunteers having signs of burnout. Over the 10-day period, sessions simulating the diving response with monitoring of heart rate (HR), heart rate variability (HRV), blood pressure (BP), and apnea duration were administered. Burnout symptoms were assessed using the Maslach Burnout Inventory (MBI) before the intervention, immediately after, and on the 10^th and 20^th day after intervention.

Results. Over the 10-day course of diving reflex stimulation, pronounced improvements in physiological and psychoemotional parameters were observed: apnea duration increased, standard deviation NN interval (SDNN) and root mean square of successive differences (RMSSD) rose by 20–30%, the stress index decreased more than threefold, and the Baevsky regulatory systems activity index (PARS) declined from pronounced regulatory tension to values approaching the physiological norm. According to the MBI, emotional exhaustion and depersonalization shifted from high to moderate levels, indicating a reduction in burnout symptoms. The effect persisted throughout the 10- and 20-day follow-up period.

Limitations. The limitations of the study are the uniformity of the sample (female students aged of 19–23 years), the absence of the control group, and the short follow-up period. At the same time, the female composition is consistent with the predominant participation of women in occupational groups with the high risk of burnout development (teachers, nurses,), which does not detract from the significance of the results, but emphasizes the need for further research using the wider and more diverse sample.

Conclusion. The method of diving reflex stimulation appears to be the effective, affordable, and safe tool for individual exposure, contributing to reducing the severity of the symptoms of occupational burnout and the formation of the stable pattern of autonomic self-regulation.

Compliance with ethical standards. All procedures involving human participants were carried out in full accordance with the ethical standards of the institutional and national research committee, as well as with the principles of the Declaration of Helsinki of the World Medical Association (2013 revision) and the European Community Directives (86/609/EEC). The study was approved by the Local Commission on Bioethics of Karaganda Medical University (Protocol No. 17 dated October 22, 2024).

Contributions:
Smagulov N.K. – study conception and design, data collection and analysis, manuscript writing and editing;
Ageyev D.V. – study conception and design, data collection and analysis, manuscript writing.
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 research was carried out within the framework of grant funding from the Ministry of Science and Higher Education of the Republic of Kazakhstan, grant No. AP26100059.

Received: June 24, 2025 / Revised: September 4, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. The article reflects the problem of the development of stomach cancer in medical workers under the influence of industrial factors, including those with carcinogenic effects, as well as risk factors including hereditary, nutritional, infectious, environmental and lifestyle factors. The appearance of the first symptoms and latent course, as well as the long-term development of the tumor, does not always make it possible to correlate the emerging malignant process with carcinogenic factors in the workplace.

Materials and methods. In our study, we analyzed the incidence of prostate cancer among medical and non-medical workers of the same medical institutions using statistical analysis.

Results. The article notes that knowledge of modern technologies for the diagnosis of precancerous diseases, widespread cancer awareness in such risk groups as medical workers in medical institutions in Primorsky Krai and risk factors (working conditions) did not lead to an increase in the detection of malignant diseases at the initial stages (0, 1, 2).

Limitations of the study: patients with malignant gastric tumors who worked in medical institutions of Primorsky Krai were examined only.

Conclusion. Ways to solve this problem are presented in this article. We have reviewed and systematized such factors of the production environment of medical institutions that are considered less studied and that have a adverse impact on the health in staff, as well as proposed preventive measures aimed at minimizing the identified risks.

Compliance with ethical standards. The study did not require ethics approval because it did not involve human participants. It was based entirely on data from registration forms.

Contributions:
Tokareva E.O. – obtaining data for analysis, developing research design, curating data; conceptualization; writing the text of the manuscript; review of publications on the topic of the article;
Alenitckaia M.V. – software; editing of the material; writing the text of the manuscript; verification; visualization.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Acknowledgements. The article was prepared with the support of DSc (Medicine), Professor, Corresponding member. RAS K.V. Stegnia in the framework of a research project.

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

Funding. The study had no sponsorship.

Received: June 5, 2025 / Revised: July 4, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Vitamin D deficiency affects a person’s psycho-emotional state and has been shown to be associated with depression and anxiety.

Aim of the study. To evaluate the prevalence of signs of anxiety and depression in students at different degrees provision of the organism with D-vitamin.

Materials and methods. To detect anxiety/depression, one hundred ninety four healthy students of both sexes were interviewed using the HADS questionnaire during the period of lowest solar insolation (October-April). Serum 25-OH of vitamin D was determined. Correlations between signs of anxiety/depression and different D vitamin levels were evaluated.

Results. Signs of anxiety were detected in 37.1 ± 3.5% of the examined subjects, and depression – in 20.1 ± 2.9%. Among students with vitamin D deficiency, there were 2.5 times more people with signs of anxiety than with signs of depression (p < 0.001), while those with subclinical signs of anxiety were 4 times more than those with clinical signs (p < 0.05). Among volunteers without signs of anxiety, the average 25-OH D value was 1.8 times higher than among those who had these signs (p < 0.001) In clinically expressed anxiety, the 25-OH D level was statistically significantly lower than in subclinically expressed anxiety by 1.4 times (p < 0.05). In the absence of signs of depression, the 25-OH D value exceeded that in their presence by 2.1 times (p < 0.001). Signs of anxiety were determined at a vitamin D level within the “deficiency” range (Me –10.14; Q₁ – 7.48; Q₃ – 15.8), and signs of depression – within the “severe deficiency” range (Me – 8.23; Q₁ – 6.09; Q₃ – 11.51; p = 0.001). A decrease in the vitamin D level was determined with insufficient UV insolation: for seven months of the year (from September to March), the erythemal power is 2.58 times lower than from April to August; in case of deficiency and severe deficiency of vitamin D, the correlation between its content and signs of anxiety is inverse, noticeable (rs = –0.5; p = 0.01), and the correlation with signs of depression is inverse, moderate (rs = –0.45, p = 0.01).

Limitations. Healthy university students examined at lowest solar insolation who had not taken vitamin D during the year.

Conclusion. Reduced provision of vitamin D is a risk factor for the formation of anxiety and depression in students, which necessitates prevention in the fall-winter-spring period of the year.

Compliance with ethical standards. The study was conducted in compliance with the ethical standards of the Declaration of Helsinki of the World Medical Association. An opinion was obtained by the Ethical Committee of I. Kant BFU (Protocol No. 38 of 03/31/2023). Each study participant gave informed voluntary written consent to participate in the study and to release personal medical information in an anonymized form.

Contributions:
Rakhmanov R.S. – concept and design of the study, writing the text;
Tarasov A.V. – collection, systematization of primary material, preparation of the text;
Skoblina N.A. – editing the final version of the article;
Piskarev Yu.G. – statistical processing of the material;
Razgulin S.A. – collection of literature data, participation in the interpretation of the results.
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: April 1, 2025 / Revised: May 22, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. In the modern period, the reservoirs of the Azov-Black Sea basin continue to be sources of commercial fish species. In this regard, monitoring for the levels of accumulation of toxicants is the main task in assessing the physiological and biochemical state of fish in terms of reproduction and their use as food.

The purpose. To assess the safety of commercial fish species in the Azov-Black Sea basin.

Materials and methods. Based on studies conducted during 2024, there were determined the levels of accumulation of polychlorinated biphenyls (PCBs), pesticides, toxic elements, and specific activity of radionuclides in the muscles of tulka, anchovy, pilengas, crucian carp, atherina, gobies,gloss’s flounder, whiting, sprat, loofah, horse mackerel, and perch, caught in the Azov and Black Seas.

Results. The results obtained during 2024 for toxicants in fish are correlated with the current fish as food standard. The results obtained over 2024 were compared with the retrospective data (2020–2023). The analyses were carried out in accordance with certified methods included in the scope of accreditation of the Analytical Testing Center of the Azov-Black Sea branch of the Scientific Research Center of the Russian Federation VNIRO Federal State Budgetary Scientific Institution.

Limitations. The limitations are related to the specifics of sampling: the study was limited to the maximum possible selection of biological resources.

Conclusion. Low concentrations of pesticides and toxic elements (lead, cadmium, mercury, arsenic), and PCBs were detected, the specific activity of caesium-137 and strontium-90 was recorded at a low level. Therefore, tulka, hamsa, pelengas, crucian carp, atherina, gobies, Gloss flounder, whiting, sprat, lufari, horse mackerel are suitable for food in terms of pollution and radiation safety in accordance with the requirements of TR CU 021/2011.

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

Contribution:
Korablina I.V. — research concept and design, writing, editing, approval of the final version, responsibility for the integrity of all data;
Gorgola L.G., Petrenko A.A. — collection of material and data processing, editing;
Kosenko Yu.V. — approval of the final version; responsibility for the integrity of all data;
Mkhitaryan I.D. — collection of material and data processing;
Ekik V.S. — collection of material and data processing.

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: May 14, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Research conducted over the past decades indicate to the essentiality (vital necessity) of the ultratrace element lithium. One of the criteria for the essentiality of trace elements (TE) is their participation in natural food chains of the type “soil-water-plants-human”, “water-human”. The paper presents the results of systematization of the literature on the participation of lithium in natural food chains. When searching for literature in English-language databases (Pubmed, Scopus, Web of Science, EMBASE), the query “lithium AND (soil OR plants OR food chain OR human nutrition OR dietary intake OR nutrient) NOT batteries NOT niobate NOT electrodes NOT materials NOT anode” was used, which found one thousand eight hundred sixty seven reports; when searching in the Russian-language RSCI on this topic, 120 reports were found. The systematization was carried out using topological data analysis methods with the selection of a representative set of publications. It has been shown that fertilizing soil with lithium salts improves the bioaccumulation of lithium by plants and increases the growth rates of useful (agricultural) plants (lettuce, spinach, potatoes, etc.). Lithium in soils improves the fixation of carbon and nitrogen by plants. Lithium, especially in inorganic forms (sulfate, carbonate, chloride) is most actively absorbed by plants, and humans and animals absorb it from plants. Available foods contain very small amounts of lithium: the average daily lithium intake is less than 140 µg / day with a recommended daily lithium intake of 1000 µg/day for adults. Ecologically significant doses of lithium (in particular, the content in drinking water) have a beneficial effect on health, leading to a decrease in suicide rates and violence on a population scale. Enrichment of various mushroom cultures with lithium is a promising direction for increasing the lithium supply of the human diet.

Contribution:
All authors took an equal part in writing the article.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Acknowledgment. The authors express their sincere gratitude to DSc (Biology), professor V.M. Kodentsova for her advisory assistance in preparing the article.

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

Funding. The study had no sponsorship.

Received: May 23, 2025/ Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Cadmium is one among the priority ecopollutants. The absence of a lethal or immediate impact on animals does not preclude the possibility of cadmium accumulating in specific organs and tissues, resulting in adverse consequences.

Materials and methods. Male mature Wistar rats were used for the experiment. The experimental groups received a dose of cadmium acetate dihydrate equivalent to 1/50 of the LD₅₀, dissolved in drinking water, for 28 days, followed by 28 days on regular drinking water. The control groups consumed regular drinking water. The cadmium content was measured using the atomic adsorption method (KVANT-2AT, Russia) on days 7, 14, 21, 28, and 56 in 19 biological media.

Results. Elevated cadmium levels were observed in all studied biological media on day 7 under conditions of subchronic intoxication, except for gum and brain tissues. The highest levels of cadmium are found in the liver, small intestine, kidneys, and plasma. After the cessation of cadmium intake, the metal level is restored to the control values in the submandibular salivary glands, brain and lungs.

Limitations. Only one Wistar line was used for the laboratory experiment. The toxicant was administered orally in the form of cadmium acetate dihydrate of the same concentration.

Conclusion. The affinity of cadmium to various biological media is characterized by significant variability in the entire period of intoxication. The liver, small intestine, kidneys, and plasma act as metal accumulators. The concentration of cadmium in the liver and kidney tissues in the animal is the most likely indicator of the cadmium poisoning.

Compliance with ethical standards. The study was approved by the Regional Ethics Committee of Kursk State Medical University (protocol No. 3 of October 17, 2022), carried out in accordance with the ethical principles of working with animals for scientific purposes governed by «Directive 2010/63/EU of the European Parliament and of the Council on the protection of animals used for scientific purposes» and national standards. This article does not contain results from studies involving human subjects.

Contribution:
Korolev V.A. – the concept and design of the study, editing;
Babkina L.A. – the concept and design of the study, information search, statistical processing and analysis of research results, writing text;
Felker E.V. – the concept and design of the study, analysis of the results;
Usachev M.A. – conducting an experiment, analyzing samples, and processing data;
Chertova R.Y. – information search, experiment, data processing;
Artemova I.A – conducting an experiment, analyzing samples;
Magomedova D.R., Ryzhaev V.A. – conducting an experiment, collecting 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 work was carried out at the expense of Kursk State Medical University.

Received: June 20, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Chronic stress and paracetamol exposure are among the most relevant factors affecting neurochemical and molecular processes in the brain in modern humans. Excessive activation of inflammatory and oxidative pathways during chronic psychosocial stress can lead to a decrease in the expression of neuroprotective and antioxidant genes, exacerbating the neurotoxic effects of drugs such as paracetamol.

Objective. To assess the effect of chronic unpredictable stress and oral administration of paracetamol, as well as their combined effect on the morphological state of the brain and on the expression of genes of the antioxidant system and neurotrophic factor in the hippocampus in rats.

Materials and methods. The experiment was conducted on forty eight rats (males and females in equal numbers), divided into four groups: control, chronic stress, paracetamol, combined exposure to stress and paracetamol. A complex of various stressors was used to model chronic stress. Paracetamol was administered orally at a dose of 1000 mg/kg. The morphological state of the hippocampus was assessed histologically, gene expression - by quantitative real-time PCR. Statistical analysis included bootstrapping and correction for multiple comparisons using the Holm-Bonferroni method.

Results. Macroscopic and histological examination of the rat brain showed the preservation of the normal anatomical structure and integrity of the hippocampal tissues in all groups. Statistical analysis of gene expression showed animals treated with paracetamol (groups III and IV) to show a significant decrease in the mRNA levels in the Sod1 and Bdnf genes in the hippocampus compared to the control and the group exposed to stress only (group II). The expression level of Sod1 and Bdnf was significantly lower in both males and females in these groups (p = 0.001). For the Hmox1 gene, a significant decrease in expression was found only in males in the paracetamol-treated group, while no changes were noted in females.

Limitations. Laboratory animals of the same biological species were used for the experiment, and the toxicant was used in only one concentration.

Conclusion. Thus, paracetamol, both in isolated use and in combination with chronic stress, has a more pronounced inhibitory effect on the expression of key genes of antioxidant protection and neurotrophic support than stress alone.

Compliance with ethical standards. Date of the meeting of the bioethics commission of theUfa Research Institute of Occupational Medicine and Human Ecology dated 02/08/2024 No. 01–02. 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.

Contributions:
Gizatullina A.A. – concept and study design, material collection and processing, statistical analysis, manuscript writing;
Valova Ya.V. – material collection and processing, statistical analysis;
Mukhamadieva G.F. – editing;
Karimov D.O. – concept and study design, statistical analysis;
Karimov D.D. – material collection and processing;
Ryabova Yu.V. – material collection and processing;
Khusnutdinova N.Yu. – material collection and processing;
Khmel A.O. – material collection and processing.
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 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: April 30, 2025 / Revised: July 9, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. The ovaries are among the key organs of the female reproductive system, responsible for oocyte formation and maturation, as well as the synthesis of sex hormones. Disruptions in these processes, caused by various environmental contaminants, can lead to a range of pathological conditions. Assessing the distribution of plastic microparticles of different sizes is thus critically important for predicting potential reproductive health risks in women.

The aim of our study. To determine and compare the characteristics of accumulation of plastic microparticle (100, 500, and 1000 nm) in the ovaries of female Wistar rats following acute systemic administration, using a specially developed software for automated quantitative analysis of fluorescent images.

Material and methods. Twelve female Wistar rats were divided into four groups; each group received an intracardiac injection of a 0.5 mL suspension of fluorescent polystyrene microparticles (MP) with diameters: 100, 500, and 1000 nm) or saline (control). Accumulation of microplastic in ovarian tissue was evaluated by fluorescent microscopy with a descriptive approach and a software designed for quantitative assessment of microparticles and their conglomerates. Data were analyzed using the Bootstrap method with Holm–Bonferroni correction; differences were considered significant at p < 0.05.

Results. Only occasional background signals were registered in the control group. All experimental groups demonstrated a significant increase in both the number and total area of microparticles compared to control (p < 0.05), with the highest overall accumulation found in the “MP 1000” group. Smaller particles (100 nm) displayed a pronounced tendency to form large conglomerates, whereas 1000 nm particles were primarily present as individual deposits.

Limitations. The investigation was limited to examining the distribution of three sizes of plastic MP within a single experimental series and a single animal species (laboratory rats), without accounting for the estrous cycle phase.

Conclusion. Even a short-term exposure to plastic MP can result in their accumulation in ovarian tissue, with the location pattern and the likelihood of conglomerate formation depending on the particle size.

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. 01-02 from February 8, 2024).

Contribution:
Ryabova Yu.V. – research concept and design, writing the text, preparing figures;
Muhammadieva G.F. – conducting the experiment, scientific editing of the text;
Valova Ya.V. – research concept and design, data collection and processing;
Khmel A.O. – conducting the experiment, data collection and processing;
Repina E.F. – research concept and design;
Karimov D.O. – research concept and design;
Ahmadeev A.R., Khusnutdinova N.Yu., Kudoyarov E.R. – conducting the experiment.
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 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: April 4, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Improving the accuracy, effectiveness, and safety of magnetic contrast media for MRI diagnostics is an urgent task for both clinical medicine and researcher. Therefore, the introduction of new innovative drugs opens up additional opportunities for assessing the functional state of organs and tissues, significantly increasing the accuracy of diagnosis and the effectiveness of treatment.

Materials and methods. The parameters of acute toxicity, species and sexual sensitivity to an innovative drug containing gadolinium nanoparticles stabilized with arabinogalactane (GD-AH) and a commercial drug for MRI studies, Gadodiamide (a reference drug), were evaluated using the intragastric route of administration in outbred rats of both sexes at a dose of 2000 mg/kg body weight (b.w.). Additionally, acute toxicity assessment for the innovative drug GD-AG was performed with intraperitoneal administration in mice at doses of 2000 and 300 mg/kg b.w.

Results. Intragastric administration of Gadodiamide and the innovative Gd-AG nanocomposite to rats of both sexes caused neither the death of animals nor changes in internal organs during macroscopic examination. Intraperitoneal administration of 2000 mg/kg b.w. GD-AG to mice resulted in 100% death. A dose of 300 mg/kg b.w. did not cause death, but macroscopic changes in internal organs were observed.

Limitations. The study is limited to studying the acute toxicity parameters of an innovative drug containing gadolinium nanoparticles stabilized with arabinogalactane (GD-AG) and a commercial drug for MRI studies, Gadodiamide.

Conclusion. According to the toxicometric parameters of acute toxicity, the average lethal doses for intragastric administration of the commercial drug Gadodiamide and the innovative nanocomposite Gd-AG to rats do not differ from each other and are definted as >2000 mg/kg b.w., which characterizes them as substances with a low risk of acute toxicity (hazard class V). The average lethal dose for the intraperitoneal route of administration of Gd-AG nanocomposite is in the range of 300 mg/kg b.w. < LD₅₀ < 2000 mg/kg b.w., which belongs to the IV class of acute toxicity according to the classification of K.K.Sidorov and is defined as a substance with low toxicity.

Compliance with ethical standards. The study was approved by the local Ethics Committee of the FSBSI VSIMEI (Protocol No. 8 dated 12/15/2023), conducted in accordance with the European Convention for the Protection of Vertebrate Animals Used for Experiments or Other Scientific Purposes (ETS N 123), Directive of the European Parliament and of the Council of the European Union 2010/63/EC dated 09/22/2010 on the protection of animals used for scientific purposes.

Contribution:
Sosedova L.M. – research concept and design, statistical data processing, text writing, editing;
Novikov M.A. – data collection and processing, statistical data processing, text writing;
Titov E.A. – literary study, data collection and processing, statistical data processing;
Pankova A.A. – data collection and processing, statistical data processing;
Vokina V.A. – data collection and processing, statistical data processing, text writing;
Konkova T.V. – data collection and processing, synthesis of nanocomposite, statistical data processing;
Sukhov B.G. – research concept and design, 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 research was supported by a grant from the Russian Science Foundation. Project No. 25-25-00036 "Toxicity and diagnostic properties of a promising contrast agent containing gadolinium nanoparticles encapsulated in an arabinogalactan polymer matrix".

Received: July 8, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

The article examines the history of the development of Russian marine quarantines during the 19^th century. It is based on the management and activities of the sanitary institutions of the Azov-Black Sea region, concentrated mainly on the territory of the Crimean Peninsula. The sources for the study were decrees and orders of the authorities of the Russian Empire in the sanitary and quarantine sphere, as well as documents from the Russian State Historical Archive (St. Petersburg) and the State Archive of the Republic of Crimea (Simferopol) with materials from the offices of the Kerch and Feodosiya quarantine districts. Archival data from the funds of the Medical Department of the Ministry of Internal Affairs on the creation and reorganization of the Crimean marine quarantines and their personnel were used. The studied array of documents is unique in its diversity and contains information about the purposes and functions performed by the sanitary and quarantine authorities on the territory of the Crimean Peninsula. The starting point of the emergence of the state sanitary quarantine service in Russia was the adoption of the most important regulatory document – the “Charter of Border and Port Quarantines” dated July 7, 1800. Its appearance was preceded by a whole series of decrees of the XVIII century on the introduction of quarantine regulations and the opening of the first “quarantine houses”; but these single measures did not solve the problem as a whole. There was a difficult epidemiological situation in Crimea, which was due, firstly, to the revival of international trade and the entry of many foreign ships into Crimean ports; secondly, climatic conditions favorable for the spread of infectious diseases – warm and humid weather. For the first time, the considered procedure for keeping ships under observation and disinfecting them in Crimean quarantines has significantly reduced epidemiological risks for the population. It is shown that the legislation on sanitary and quarantine institutions was repeatedly changed and tightened during the 19^th century. New medical data and methods of combating epidemics appeared, and the means of sanitary and hygienic treatment of ships and crews were improved, which significantly reduced the risk of infection entering the territory of the Russian Empire and minimized the consequences of epidemics. The task of the central authorities was to stop epidemics on the state borders and prevent their spread to the “inner” provinces of the Russian Empire. To this end, the simplest sanitary facilities were first set up in Crimea – quarantine outposts, which over time became quarantine districts with a complex management and subordination structure, with their own staff, funding and special forces – quarantine guards.

Contribution:
Borshchik N.D. developed the basic concept of the article, systematized and analyzed archival documents and printed sources, prepared and edited the text, compiled a scientific reference apparatus, and formulated the main research results.
The author is 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 was carried out at the expense of a grant from the Russian Science Foundation, project “Customs system of the Crimean Peninsula in the System of State Administration of the Russian Empire (Second Half of the 19^th Century)”, no. 24-28-01285, https://rscf.ru/project/24-28-01285/

Received: August 6, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

The article is devoted to the history of the formation and development of sanitary and educational work among the population of a large region of our country – Eastern Transbaikalia in the early 1920s. The main attention is paid to the problems of health education among the local female population. Published and unpublished sources from the collections of the State archive and the Scientific library of the Museum of healthcare history of the Trans-Baikal region as well as newspaper publications during the studied period were taken while the preparation of the article. It helped to reveal history of creation of regional soviet healthcare system including its main managing body – Trans-Baikal Provincial Healthcare Department and institutions with a female staff, such as Mother and Baby Home and Women’s Consultation in Chita. The article examines the main areas of their activities as well as activities of Soviet and party bodies, public health and education institutions to attract Trans-Baikal women to sanitary and educational work, to disseminate new knowledge, medical and everyday practices among them. There was made a conclusion that the beginning of sanitary and educational work among the women of Eastern Transbaikalia dates to the period of final establishment of the Soviet administration in the region (1923). The main methods of work were lectures, reports, and agitation campaigns. The local periodical press was also involved in sanitary and educational work. This work was of great importance for the Soviet government’s policy to resolve the “women’s question” – the struggle for the equal status of women in all spheres of public life, as well as to strengthen the public health of women and children in Eastern Transbaikalia.

Contribution:
Moroz A.I. – the concept and design of the study, collection and processing of material, writing text, editing.
The author is 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: August 4, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

The article is dedicated to the outstanding German scientist-innovator, physician, and hygienist, Professor Max von Pettenkofer (1818–1901). He belonged to the scientific elite of the 19^th century. Little-known facts from the life of the scientist are given. It is noted that thanks to his rigorous search for the laws of nature and the struggle for scientific truth, M. Pettenkofer left a significant mark on science. In the field of hygiene, he looked for ways and means of maintaining health and preventing diseases. With his methodology of consistent application of the experimental method in the field of public health, M. Pettenkofer helped the hygienic discipline provide accurate and reliable answers to sanitary questions. There is analyzed circumstance that in his experimental work on hygiene, M. Pettenkofer looked for an answer to all current questions concerning the relationship between human and his environment. For productive movement in this direction, M. Pettenkofer combined then the progressive knowledge of medicine with physics, chemistry, technology, and statistics. Thus, modern “cross-thinking” made hygiene the first interdisciplinary medical field, and of course, professor M. Pettenkofer deserves a great deal of credit for this.

Contributions. All authors made substantial contributions to the conception, conduct of the study, and preparation of the article. 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: May 3, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026