Background: Although food-borne infectious diseases occur across all age groups globally, evidence indicates that young children, older adults, and immunocompromised individuals are disproportionately affected due to their increased susceptibility to enteric pathogens. Young children in particular are at higher risk because their immune systems are not yet fully developed and they have lower body mass, which together reduce their ability to resist and recover from food-borne infections. In Mongolia, reported cases of intestinal infectious diseases in 2024 exceeded the ten-year historical average by 504.5 cases, and food- and water-related infections such as hand-foot-and-mouth disease, dysentery, and salmonellosis remain predominant among these conditions. Aim: The objective of this study was to conduct microbiological analyses of school lunches and drinking water provided to general education school students and to evaluate their compliance with relevant national standards. Materials and Methods: A total of 107 school lunch samples and 35 drinking water samples collected from general education schools were included in the study. Microbiological analyses were performed to assess hygiene and safety indicators, including Listeria monocytogenes, Salmonella spp., total coliform count, total viable microbial count (TVC), and intestinal bacteria. Laboratory analyses were conducted at the Microbiology Laboratory of the Food Safety Reference Laboratory under the Standardization and Metrology Authority. Confirmatory identification of microorganisms was performed using the VITEK 2 Compact system. Result: Of the 35 drinking water samples analyzed for 105 parameters, 8.5% (n=3) exceeded the permissible limits for total microbial counts. In the 107 school lunch food samples, a total of 428 microbiological parameters were examined, of which 26.1% (n=28) showed coliform counts above the allowable limits specified in the MNS 6308:2012 standard. Additionally, enterobacteriaceae were detected in 42.9% (n=46) of the food samples. When analyzed by school, 51.5% of the 35 schools (18 schools) had food samples with coliform counts that did not meet the standard requirements, whereas 49.5% (17 schools) showed compliance with the standards. These findings indicate that, on average, one out of every two schools fails to meet the required hygiene practices, proper food production procedures, and microbiological safety standards in meal preparation. Conclusion Microbiological analysis of 107 food samples from 35 general education schools across 428 indicators revealed that 26.1% did not meet the requirements of the MNS 6308:2012 “Microbiological safety and hygiene criteria for food products” standard due to excessive coliform counts. Of the 35 drinking water samples analyzed for 105 indicators, 5.7% (n=2) failed to meet the requirements of the MNS 0900:2018 “Drinking water: Hygiene requirements, quality, and safety assessment” standard with respect to total viable microbial count.

Background: Dental caries is a worldwide spreader infectious decease. According to the present studies, the prevalence of the disease is highly dependent on the developmental of the country and its prevention strategies. By the World Dental Federation and World Health Organization (WHO) criteria, dental caries prevalence is increasing every year in Mongolia, which is becoming one of the main problems in our country. According to studies, the most effective method of decreasing prevalence of caries is to have an oral health knowledge, provide caries treatment on early-stage and focusing more on prevention. Aim: The aim of our study was to determine the oral health status among the groups aged between 5, 12, 35-44, 65-74. Materials and Methods: The study has consisted 3512 subjects who selected from 4 age groups (5, 12, 35-44, 65-74) and from 6 districts of Ulaanbaatar city and 5 provinces of Mongolia. The oral examination of each person was done by calibrated dentists according to recommendation of WHO, 2013. The statistical analysis was processed using statistical software system (Stata version 16.0). Result: The prevalence of dental caries and mean of Decayed, Missed, Filled, permanent teeth (DMFt), decayed filled primary teeth were 87.6%, 6.2±0.14 among 5 years old, 77.0%, 2.2±0.03 among 12 years old, 98.1%, 11.8±0.19 among 35-44 years old, 99.8%, 23.6±0.27 among 65-74 years old. The good oral hygiene index was 51.5%, 46.3%, 49.0% and 65.7%. The prevalence of gingivitis was 2.3%, 9.8%, 34.5%, 17.6% and of calculus 0.8%, 7.6%, 62.8%, 31.6%, respectively above groups. The percent of people with removable dentures among 65-74 years old was higher than among 35-44 years old. Conclusion Across multiple age groups, the prevalence and severity of dental caries remain high. Oral hygiene status is predominantly classified as fair to poor. Among adults, partial or complete tooth loss is common; however, the utilization of dental prostheses is low, indicating inadequate prosthetic rehabilitation and limited adaptation to tooth replacement.

Background: Numerous studies have shown that air pollution is a serious public health threat and risk worldwide. Mongolia is the world leader in outdoor and indoor air pollution, and the morbidity and mortality caused by it are increasing every year. People spend most of their lives indoors, and it is necessary to regularly assess and study indoor air pollution. Aim: To study the concentration of PM2.5 particles in the indoor air of households in Ulaanbaatar and Darkhan cities in relation to some symptoms of respiratory diseases. Materials and Methods: The study was conducted using an analytical cohort design from October 2023 to July 2025, and the 4 districts of the central Ulaanbaatar city and Darkhan cities were included in the study. A total of 240 households were included in the study, including 48 households living in ger and house, 24 households living in apartments, and 48 households living in ger and house, and 24 households living in apartments from Ulaanbaatar city. A direct measurement device (PurpleAir) was installed in the households for 3-4 weeks to measure PM2.5 particles in the indoor air for 24 hours. After measuring PM2.5 particles in the indoor air of the household, data were collected through questionnaires from the participants aged 18-60 who participated in the study and underwent health examinations. The results were processed using STATA-19.0 and R programs. Result: 213-239 households were selected for the study, including households living in 17-26 apartments, 42-58 houses, and 38-50 houses. The 24-hour average concentration of PM2.5 particles in the ambient air of households in Ulaanbaatar city was measured relatively higher in winter and summer than in households in Darkhan city. Among the districts of Ulaanbaatar city, the highest concentration of PM2.5 particles was measured in Songinokhairkhan district, and the lowest concentration was measured in Bayanzurkh district. Considering the cities by heating type, households with stoves are more polluted than households with centralized heating. In Darkhan city, the lowest concentration was measured in apartments (22.78-31.53 μg/m³), houses (44.53-68.17 μg/m³), and the highest concentration was measured in traditional felt houses (houses) (63.20-68.25 μg/m³). In Ulaanbaatar, PM2.5 concentrations were relatively high in all types of housing, including apartments (41.61-58.37 μg/m³), houses (79.22-92.50 μg/m³), and traditional felt dwellings (76.69-86.31 μg/m³). In the summer, PM2.5 concentrations in Darkhan were 3.10-10.03 μg/m³ in apartments, 7.67-14.37 μg/m³ in houses, and 7.98-17.90 μg/m³ in traditional felt dwellings (houses). The concentration of PM2.5 particles in the ambient air of the settlement is statistically significantly associated with shortness of breath, fatigue, weakness, muscle pain, nausea, palpitations, sneezing, runny nose, conjunctivitis, pain in the eye socket, tearing of the eyes, headache, fever, nasal congestion, cough, loss of appetite, sore throat, phlegm, wheezing, and chest pain. Conclusion The 24-hour average concentration of PM2.5 particles in indoor air in households in Ulaanbaatar and Darkhan cities is higher than the Mongolian standard during winter and is statistically significantly associated with some symptoms of respiratory diseases.

Background: Oral squamous cell carcinoma (OSCC) is the most common subtype of head and neck squamous cell carcinoma (HNSC) and poses a serious threat to human health. The molecular mechanisms underlying the initiation and progression of OSCC are highly complex. Although notable advances have been made in diagnostic and therapeutic technologies in recent years, the five-year survival rate of patients has not improved substantially. Therefore, in-depth investigation of the molecular mechanisms of OSCC, identification of potential diagnostic and therapeutic biomarkers, and development of effective treatment strategies have become critical directions in current research. Aim: To investigate the relationship between the prognosis of HNSC/OSCC and the m7G-related lncRNA GSEC. Materials and Methods: RNA-seq transcriptome data and clinical data for HNSC were downloaded from The Cancer Genome Atlas (TCGA). Differential expression analysis of lncRNAs was performed, and differentially expressed lncRNAs were selected. Univariate Cox regression analysis was used to screen lncRNAs associated with prognosis. The random forest algorithm was employed to rank the importance of differentially expressed lncRNAs, and the top 50 lncRNAs were selected. Twenty-nine m7G-related genes were obtained from published literature. m7G-related lncRNAs were screened based on Pearson correlation analysis. The intersection of these results was taken to identify diagnostic biomarker m7G-related lncRNAs. The UALCAN database was used to analyze the expression of target m7G-related lncRNA in HNSC/OSCC. cBioPortal was used to analyze the gene mutation profile of GSEC in HNSC. Co-expressed genes of the target lncRNA in HNSC were collected via cBioPortal, filtering for genes with FDR<0.05 and R>0.4. GO/KEGG enrichment analysis was performed using the Metascape database. Immunohistochemical expression levels of the m7G-related gene were analyzed using the Human Protein Atlas (HPA) database. The expression level of the m7G-related lncRNA in cells was detected using qRT-PCR. Result: A total of 3,618 differentially expressed lncRNAs were identified in HNSC from the TCGA database, including 2,421 upregulated and 1,197 downregulated genes. Univariate Cox regression analysis showed that 1,306 lncRNAs were significantly associated with HNSC patient prognosis (P<0.05). The random forest algorithm ranked the top 50 important lncRNAs. Pearson correlation analysis (|correlation coefficient|>0.5, P<0.001) identified 310 m7G-related lncRNAs. Taking the intersection with lncRNAs significant in the random forest and univariate Cox regression analyses revealed that the m7G-related lncRNA GSEC has significant diagnostic value in HNSC, with DCPS identified as the m7G-related gene for lncRNA GSEC. GSEC/DCPS were significantly upregulated in HNSC/OSCC (P<0.05). High expression of GSEC showed value in predicting poor outcomes in OSCC (AUC=0.937). Analysis of the mutation spectrum of the target gene GSEC indicated that GSEC undergoes genetic mutations in HNSC, including amplification and altered mRNA expression levels. Enrichment analysis of GSEC co-expressed genes in HNSC (FDR<0.05, R>0.4) revealed that GO terms were primarily enriched in the endoplasmic reticulum lumen, glycoprotein metabolic process, and collagen fibril organization. KEGG pathways were mainly enriched in Protein processing in endoplasmic reticulum, Glycosaminoglycan biosynthesis-heparan sulfate/heparin, and Lysine degradation. Immunohistochemical analysis revealed high expression of DCPS, the m7G-related protein within the GSEC, in OSCC tissues compared to normal mucosal tissues. Further qRT-PCR detection demonstrated that GSEC is upregulated in OSCC cell lines relative to NHOK cells. Among the OSCC cell lines examined, CAL-27 exhibited the most pronounced upregulation of GSEC expression compared to SCC-4 and HSC-2 cells. Conclusion Bioinformatics analysis in this study revealed significant upregulation of the m7G-related GSEC/DCPS in HNSC/OSCC. Moreover, GSEC/DCPS expression was correlated with the prognosis of HNSC/OSCC. These findings suggest that GSEC/DCPS may serve as a novel molecular target for the diagnosis and treatment of HNSC/OSCC.

Background: Visual impairment may negatively affect children’s daily activities, educational opportunities, and hygiene practices, including their ability to maintain oral hygiene independently. Therefore, assessing the oral health status of visually impaired children is important for improving access to dental care services and developing preventive oral health programs. Aim: To compare the oral health status of visually impaired and sighted children. Materials and Methods: A total of 174 children from grades 1–12 of School No. 116 for visually impaired children and Logarithm School in Ulaanbaatar were included in this study. Oral examinations were conducted using an examination form developed according to the World Health Organization (WHO, 2013) guidelines. The study was carried out using a descriptive cross-sectional design, and the collected data were statistically analyzed. Result: Among visually impaired children, the prevalence of dental caries was 77%, with a mean DMFT index of 4.4±3.8. Among sighted children, the prevalence of dental caries was 75.9%, with a mean DMFT index of 4.7±3.8. The prevalence of gingivitis was 18.4% in visually impaired children and 11.5% in sighted children. Oral hygiene status was predominantly classified as poor or fair among visually impaired children, whereas a good level of oral hygiene predominated among sighted children. Conclusion 1. The prevalence and severity of dental caries were similar between visually impaired and sighted children. 2. The prevalence of gingivitis was comparable between visually impaired (18.4%) and sighted children (11.5%). 3. Oral hygiene status was generally poorer among visually impaired children, while sighted children predominantly demonstrated good oral hygiene.

Background: Type I hypersensitivity, commonly known as an allergic reaction, is characterised by an IgE-mediated immune response triggered when foreign proteins enter the body. During allergic reactions, cytokines such as IL-4, IL-5, IL-9, and IL-13, secreted by T-helper 2 (Th2) cells, play a crucial role in activating immune effector cells like eosinophils and mast cells, which contribute significantly to airway inflammation and obstruction. Conversely, interferon-gamma (IFN-γ), produced by Th1 cells, suppresses Th2-mediated responses and plays an essential role in regulating allergic inflammation. Therefore, determining the balance of cytokines produced by Th1 and Th2 cells is crucial for understanding the mechanisms underlying allergic responses. Aim: We aimed to induce an allergic response in experimental animals using ovalbumin and to determine the levels of IL-4 and IFN-γ cytokines using an in-house enzyme-linked immunosorbent assay (ELISA). Materials and Methods: A total of 20 female C57BL/6 mice aged 6–8 weeks were selected for the experiment and randomly divided into two groups: control and experimental groups. The concentrations of IL-4 and IFN-γ cytokines in mouse serum were determined using an in-house enzyme-linked immunosorbent assay (ELISA). Result: Compared to the control group, the levels of IL-4 and IFN-γ cytokines in the serum of allergic model-induced C57BL/6 mice were determined to be 513.7 pg/mL and 193.2 pg/mL, respectively. A statistically significant difference was observed in IL-4 cytokine levels between the two groups (p < 0.001). Conclusion In the allergic model group, serum levels of IL-4 cytokine were elevated, while IFN-γ cytokine levels were decreased, suggesting a predominant Th2-type immune response.

Background: Ambient and household air pollution remain leading risk factors for global morbidity and mortality. Exposure to fine particulate matter (PM₂.₅) is associated with increased risks of cardiovascular and respiratory diseases, as well as lung cancer, metabolic and neurological disorders, and immune dysfunction. In urban areas of Mongolia, air pollution reaches critical levels during the winter season. Although improved solid fuels have been introduced in recent years, their impact on both outdoor and indoor air quality remains insufficiently characterized. Aim: To compare outdoor and household air pollution levels in Ulaanbaatar and Darkhan cities. Materials and Methods: Outdoor air pollution data for Ulaanbaatar were obtained from fixed monitoring stations of the National Agency for Meteorology and Environmental Monitoring for the period 2014–2026, with seasonal comparisons performed. For indoor air quality assessment, a longitudinal study was conducted among 240 households (apartments, houses, and traditional gers) in Ulaanbaatar and Darkhan from 2023 to 2026. PM₂.₅ concentrations were measured using real-time sensors (PurpleAir sensor), deployed for 14–21 days per season (winter and summer) in each household, recording data at 10-minute intervals over 24-hour periods. Result: Between 2014 and 2026, the 24-hour mean concentrations in Ulaanbaatar were 60.5 µg/m for PM₂.₅, 117.3 µg/m for PM₁₀, 37.3 µg/m for NO₂, 41.8 µg/m for SO₂, and 27.5 µg/m for O₃. While particulate matter levels showed a decreasing trend following the introduction of improved fuels, SO₂ concentrations increased, and overall pollution levels remained higher than those observed in Darkhan. Indoor PM₂.₅ concentrations were higher in Ulaanbaatar compared to Darkhan (60.7±86.1 vs 48.4±96.7 µg/m). Significant differences were observed by housing type (p<0.0001), with higher concentrations in households using solid fuels (houses and gers) and lower levels in apartments. These findings indicate substantial variability in indoor air pollution by city, housing type, and season, with persistently elevated exposure levels. Conclusion Outdoor air pollutant concentrations in Ulaanbaatar, including particulate matter, NO₂, and SO₂, exceed national standards and WHO guideline values by 1–4 times. Indoor PM₂.₅ pollution is higher in Ulaanbaatar than in Darkhan and varies significantly by housing type and season, indicating a high and heterogeneous exposure burden among urban populations.

Background: Children with disabilities experience long-term impairments in one or more developmental domains, including cognitive, communicative, motor, behavioral, sensory, and self-care functions, often requiring continuous support in daily life. These children are particularly vulnerable to poor oral health due to a combination of factors such as limited motor coordination, dependence on caregivers, longterm medication use, and unfavorable dietary patterns. Consequently, they are at increased risk for dental caries, periodontal diseases, and oral infections. In Mongolia, oral health disparities among children with disabilities remain insufficiently explored, and evidence-based data on their treatment needs are limited. Addressing this gap is essential for planning targeted preventive and therapeutic strategies. Aim: To evaluate the oral health status and determine the dental treatment needs of children with disabilities in Ulaanbaatar, Mongolia. Materials and Methods: A descriptive cross-sectional study was conducted among 888 children with disabilities attending special education schools in Ulaanbaatar. Oral examinations were performed following ethical approval (No. 2023/3-06) from the Research Ethics Committee of the Mongolian National University of Medical Sciences. Dental caries was assessed using dmft/DMFT indices, and oral hygiene status was evaluated using a plaque index. Data were analyzed using Stata 16.0, with statistical significance set at p<0.05. Result: The overall prevalence of dental caries was 85.5%, indicating a substantial disease burden. Caries prevalence and mean experience were 66.7% and 5.28±4.58 (dmft) in primary dentition, 86.2% and 5.23±3.75 (DMFT + dmft) in mixed dentition, and 83.6% and 5.44±4.00 (DMFT) in permanent dentition. Oral hygiene assessment showed that only 9.8% of children had good hygiene, whereas 46.3% exhibited poor oral hygiene, which was consistently associated with higher caries levels across diagnostic groups. Notably, 83.3% of children had at least one untreated decayed tooth or caries-related complication, reflecting a considerable unmet treatment need. Conclusion 1. The prevalence of dental caries among children with disabilities in Ulaanbaatar was 85.5%. Specifically, during the primary dentition stage, the prevalence was 66.7% with a mean caries experience of 5.28±4.58 (dmft). In the mixed dentition stage, the prevalence increased to 86.2% with a mean caries experience of 5.23±3.75 (DMFT+dmft). During the permanent dentition stage, the prevalence was 83.6%, with a mean DMFT score of 5.44±4.00. 2. Assessment of oral hygiene status using the plaque index revealed that 9.8% of the children had “Good” oral hygiene, 43.9% had “Fair” hygiene, and 46.3% had “Poor” oral hygiene. 3. The caries profile was predominantly characterized by untreated decayed teeth, and a strong direct association was observed between dental caries and oral hygiene status. Overall, 83.3% of the children required oral healthcare services and treatment, with the highest needs observed among those with permanent dentition, males, and children with intellectual disabilities.

Background: In recent years, as the demand for orthodontic treatment has increased, the need to thoroughly investigate the causes of dental and skeletal malocclusions has become more important. In skeletal Class II malocclusion, mandibular deficiency prevalence for 70–80% of cases, maxillary excess for 10–20%, and a combination of both for approximately 15% (Figure 1). In cases associated with mandibular deficiency, clinical features include severe dental crowding, deep overbite, and reduced lower facial height. These conditions negatively affect facial profile, occlusion, masticatory function, and airway. Therefore, accurate diagnosis and appropriate treatment planning are essential. Diagnosis: Skeletal Class II malocclusion, deepbite, and severe crowding. Treatment: in August 2025, using self-ligating brackets with posterior bite up placed on the molars. After 4 months, a temporary anchorage device (TAD) was inserted, and anterior retraction was performed along with vertical elastics. Within 7 months, the overjet was decreased from 7 mm to 3 mm, and the overbite decreased from 7.5 mm to 4.5 mm. Midline deviation and arch form were corrected, and molar and canine relationships improved to Angle Class I. The facial profile also showed noticeable improvement. Conclusion Within a relatively short period after treatment initiation, severe crowding was resolved, and both sagittal and vertical relationships of the anterior teeth improved to normal values. Molar and canine relationships were significantly improved, along with facial esthetics. This case demonstrates that with proper planning, TAD-supported orthodontic treatment can be an effective non-extraction approach for certain cases of skeletal Class II malocclusion with severe crowding.

Background: The cornerstone of medical education in training qualified physicians lies in foundational scientific knowledge, which forms the basis for clinical reasoning and diagnostic-therapeutic decision-making. Anatomy constitutes one of the core foundational subjects within the medical doctor training curriculum and exerts a direct influence on the development of students’ baseline knowledge and the formation of their clinical thinking. This study was conducted to evaluate the anatomy curriculum through assessments by first-year students enrolled in the basic medical education program, with the aim of enhancing instructional quality and improving the structure and organization of the course. Aim: To investigate the satisfaction ratings of first-year students in the basic medical education program regarding the Anatomy-1 course. Material and Methods: The study was carried out using an analytical cross-sectional design during the first semester of the 2025–2026 academic year. Data were collected from a total of 289 first-year students of the basic medical education program at the School of Bio-Medicine of MNUMS (Mongolian National University of Medical Sciences) using a questionnaire comprising 24 items in total—3 demographic questions, 20 general satisfaction questions, and 1 open-ended question—with each item rated on a 5-point Likert scale. Data were processed using SPSS 23.0 software, employing descriptive statistics, two-sample t-tests, ANOVA, Pearson’s correlation, and factor analysis. Results: Of the study participants, 14.2% were male and 85.8% were female, with the cohort distributed across programs as follows: TAM 10.38%, TMS 17.30%, MDS 44.29%, PDS 13.15%, and DSS 14.88%. The overall satisfaction level was 4.59±0.66, falling within the “good” range. The highest rating was attributed to “Faculty members possess strong professional knowledge and skills” (DSS, 4.91±0.37), whereas the lowest rating was assigned to “Students’ knowledge and skills are evaluated objectively and fairly” (PDS, 4.16±0.75). The internal consistency coefficient of the questionnaire yielded α=0.909, indicating excellent reliability. Correlation analysis revealed strong positive associations among instructors’ respect for students’ viewpoints (Q4), instructors’ communication and demeanor (Q5), and professional ethics (Q6) (r=0.787; r=0.755; p<0.01). Factor analysis produced a KMO value of 0.865 and a Bartlett’s test result of p=0.000; accordingly, all 20 items were grouped into two factors—”Faculty Professional Competence” and “Learning Environment and Organization”—which collectively accounted for 58.74% of the total variance. Conclusions 1. The findings indicate that the overall satisfaction of first-year basic medical education students who participated in the study was at a favorable level. 2. Faculty professional competence and the learning environment and organization were identified as factors influencing student satisfaction, explaining 58.74% of the total variance in the results. It was further established that adherence to professional ethics, respect for students’ perspectives, and equitable treatment are contingent upon the instructor’s knowledge and professional expertise.