Background: In the treatment of early gastric cancer, patients suitable for endoscopic submucosal dissection (ESD) are selected on the basis of endoscopic findings and biopsy results, while the final diagnosis is confirmed by examination of the resected specimen. Aim: To examine the discrepancies between clinical and pathological findings before and after ESD. Materials and Methods: We retrospectively identified 335 lesions treated by ESD for early gastric cancer at the National Cancer Center between 2020 and 2025, compared the endoscopic, biopsy and pathological findings, and identified the factors associated with discrepancy. Result: At least one of the three pre-treatment parameters was discordant in 175 lesions (52.2%). Of the 249 lesions judged to be ulcer-free on endoscopy, 51 (20.5%) were ulcerated histologically, while 28 lesions were overestimated (P<0.05). Underestimation of ulceration was more likely in lesions located in the upper or middle third of the stomach (OR 2.17, 95% CI 1.22–3.99) and in lesions measuring ≥20 mm (OR 1.68, 95% CI 1.00–2.84). Of the 110 lesions diagnosed as high-grade dysplasia on biopsy, 36 (32.7%) contained adenocarcinoma in the resected specimen, one of which was of undifferentiated type. Of the remaining 18 undifferentiated lesions, 6 (33.3%) had been diagnosed as differentiated type before treatment. Submucosal and lymphovascular invasion were associated with a tumor size of ≥20 mm (OR 3.58 and 3.15) and undifferentiated histology (OR 4.47 and 7.56); all P<0.01. Conclusion A significant discrepancy was observed between the pre- and post-ESD clinicopathological findings.

Background: Cisplatin is a widely used platinum-based chemotherapeutic agent, but its gonadotoxic effects can damage ovarian tissue, oocytes, and developing follicles and may lead to primary ovarian insufficiency (POI). Adipose-derived stem cells (ADSCs) are being investigated as a potential regenerative treatment because of their paracrine, anti-apoptotic, and tissue-repair effects. Aim: To evaluate the effect of ADSC therapy on estrous cyclicity, body weight, and ovarian follicular morphology in a mouse model of cisplatin-induced POI. Materials and Methods: Thirty 6-week-old female BALB/c mice were included. Six mice received saline as controls, while 24 mice received cisplatin 2 mg/kg intraperitoneally once daily for 10 days to induce POI. After POI induction, cisplatin-exposed animals were continued as an untreated POI group (n=15) or an ADSC-treatment group (n=9). The ADSC group received 1×10⁶ cells suspended in 0.2 mL medium via the tail vein. Body weight and vaginal cytology were monitored daily, and estrous stages were classified as proestrus, estrus, metestrus, and diestrus. Ovaries were collected for histologic evaluation at the end of the study. Result: After cisplatin exposure, mean estrous cycle length increased from 3.97 days in controls to 6.4 days in the POI group (p<0.05). During the post-treatment evaluation, mean cycle length was 5.65 days in untreated POI mice (n=4) and 4.5 days in ADSC-treated mice (n=7), representing a statistically significant improvement after ADSC therapy (p=0.013). Cisplatin caused significant body-weight loss, reaching a mean of 18.0 g on day 6 after completion of cisplatin administration (p<0.01). Histologically, untreated POI ovaries showed follicular atrophy and prominent degenerative changes, whereas ADSC-treated ovaries showed more morphologically preserved primary, secondary, and antral follicles and relatively fewer degenerative changes. Exploratory manual counting in three representative whole-ovary sections per group showed total intact/growing follicle counts of 15.00±2.65 in controls, 6.00±2.00 in POI, and 8.67±2.89 in ADSC-treated ovaries. Conclusion ADSC treatment was associated with partial restoration of estrous cyclicity and ovarian follicular development in a cisplatin-induced POI mouse model. These findings support further investigation of ADSC-based regenerative therapy for chemotherapy-associated ovarian injury.

Background: Globally, research on identifying bioactive compounds from medicinal plants and characterizing their in vitro and in vivo pharmacological activities is progressing rapidly. Plants native to Mongolia have adapted to unique, extreme continental climatic conditions, accumulating distinct phytochemicals, and have historically been utilized in traditional medicine and dietary practices. Establishing the non-cytotoxic safety threshold of these wild and cultivated plant extracts in RBL-2H3 mast cells a universally accepted model for type I hypersensitivity and inflammation is a vital prerequisite. Determining these baseline non-toxic dose ranges provides the essential scientific foundation for subsequent cellular allergy models, animal studies, and the elucidation of molecular mechanisms underlying their therapeutic efficacy. Aim: To determine the cytotoxicity profile and establish the non-cytotoxic dose ranges of extracts from four selected Mongolian plant species (wild and cultivated) in RBL-2H3 cells. Materials and Methods: Plant samples including lingonberry (Vaccinium vitis-idaea), strawberry (Fragaria orientalis), black radish (Raphanus sativus), and blue-berried honeysuckle (Lonicera caerulea L.) were standardly collected, authenticated, and cataloged as herbarium specimens at the Botanic Garden and Research Institute, Mongolian Academy of Sciences. A total of 12 distinct extracts were prepared from plant leaves, stems, and fruits using water and ethanol extraction, followed by concentration via rotary evaporation and freeze-drying. Rat basophilic leukemia (RBL-2H3) cells were maintained in EMEM growth medium and utilized during the exponential growth phase. Cell viability and non-cytotoxic concentration thresholds were evaluated using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Result: Ethanolic extracts of strawberry leaves, black radish, and honeysuckle leaves (≥6.25 µg/mL), as well as aqueous extracts of honeysuckle fruits (≥6.25 µg/mL) and stems (≥25 µg/mL), exhibited dose-dependent cytotoxicity. Conversely, aqueous extracts of lingonberry leaves (≤200 µg/mL), strawberry leaves (≥100 µg/mL), and black radish (≤200 µg/mL), alongside ethanolic extracts of lingonberry leaves (≥50 µg/mL), demonstrated non-cytotoxic profiles. Furthermore, ethanolic extracts of honeysuckle stems (≤300 µg/mL) and fruits (≥12.5 µg/mL), as well as the aqueous extract of honeysuckle leaves (≤50 µg/mL), significantly enhanced RBL-2H3 cell viability. Conclusion The tested plant extracts influenced RBL-2H3 cell viability in a solvent polarity and plant organ dependent manner. Ethanolic extracts of strawberry leaves, black radish, and honeysuckle leaves, along with aqueous extracts of honeysuckle fruits and stems, demonstrated relatively high cytotoxicity, reducing cell viability by >40% starting at concentrations of 12.5, 25, and 50 µg/mL. In contrast, aqueous extracts of strawberry leaves and black radish, as well as both aqueous and ethanolic extracts of lingonberry leaves, maintained low cytotoxicity at concentrations below 200 µg/mL. Notably, ethanolic extracts of honeysuckle stems and fruits (>12.5 µg/mL) and its aqueous leaf extract (<100 µg/mL) enhanced cell viability, exhibiting significant cell proliferation promoting activity.

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: 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.

Background: Allergic and atrophic forms of chronic rhinitis are common among the population, characterized by a chronic progressive course with a tendency toward increasing prevalence. Worldwide, allergic rhinitis affects approximately 10–40% of adults and 2–25% of children. According to a study conducted in Mongolia, the prevalence of allergic rhinitis among adults in Ulaanbaatar was reported to be 23.6%, with an increasing trend anticipated in the future. In allergic and atrophic rhinitis, structural alterations occur in the nasal mucosa, including disruption of the normal architecture of the pseudostratified epithelium and ciliated cells, accompanied by changes in goblet cell number and dysfunction of their activity, resulting in a complex pathological process. In otorhinolaryngology practice in Mongolia, there is a relative lack of studies investigating the ultrastructural changes of the nasal mucosa in allergic and atrophic rhinitis. Aim: To compare ultrastructural and histological changes of the nasal mucosa in allergic and atrophic rhinitis. Materials and Methods: Ethical approval was obtained from the Research Ethics Review Committee of the Mongolian National University of Medical Sciences at the meeting held on April 24, 2020 (Protocol No. 2020/З-04). Appropriate ethical permission was also obtained from the EMJJ ENT Hospital. Nasal mucosal tissue samples were collected from surgically resected specimens of patients aged 20–45 years diagnosed with allergic and atrophic rhinitis. The mucosal specimens were processed at the Institute of Biomedical Sciences of the Mongolian National University of Medical Sciences. Samples were fixed and dehydrated according to the protocol, coated with 100 Å gold, and examined using a scanning electron microscope (FEI Quanta FEG 250, USA). In addition, paraffin blocks were prepared, sectioned at 4 μm thickness, stained with Hematoxylin and Eosin, and analyzed histologically. Results: In allergic rhinitis, the pseudostratified epithelium was relatively preserved; however, disorganization of ciliated cells, partial loss of cilia, and goblet cell hyperplasia were observed. In contrast, atrophic rhinitis showed epithelial thinning, near-complete loss of ciliated structures, glandular atrophy, and submucosal fibrosis. Conclusion Allergic rhinitis is associated with relatively mild and predominantly functional mucosal alterations, whereas atrophic rhinitis demonstrates severe structural damage with irreversible impairment of mucosal protective function.

Background: The Anatomy course, which provides general foundational knowledge on the structure of all organ systems of the human body, is a core professional course in the bachelor’s curricula of Pharmacy, Biomedical Science, Hygiene and Epidemiology, Public Health, Occupational Safety and Health, and Nutrition and Dietetics. Student satisfaction is not only an important indicator of the quality of medical education, but also influences graduates’ knowledge, skills, and attitudes; therefore, continuous research in this area is necessary. Aim: To determine the level of satisfaction with the Anatomy curriculum among first-year students in basic health science programs and to identify factors influencing their satisfaction, with the aim of improving the quality of teaching. Materials and Methods: An analytical cross-sectional study was conducted from September 2025 to February 2026 among 182 first-year students enrolled in the following programs at Mongolian National University of Medical Sciences (MNUMS): Biomedical Research, Pharmacy, Health Epidemiology, Public Health, Health Informatics, and Traditional Medicine Therapy. Student satisfaction with the quality of the Anatomy course was assessed using a 24-item questionnaire. Data were analyzed using SPSS version 26, applying descriptive statistics, independent-samples t-test, one-way analysis of variance (ANOVA), Pearson correlation, factor analysis, and multiple regression analysis. A p-value of <0.05 was considered statistically significant. Results: The internal consistency of the satisfaction scale was very high (Cronbach’s α=0.928). The mean overall satisfaction score of the participants was 4.61±0.67. There was no significant difference in overall satisfaction by gender (p > 0.05). Factor analysis identified two main factors influencing the evaluation of teaching quality (KMO=0.894; Bartlett’s test p<0.001), which together explained 52.73% of the total variance. The first factor was “Teachers’ professional competence, communication, attitude, and assessment,” and the second factor was “Course organization, learning environment, and instructional materials.” Correlation analysis showed that better course organization and higher teacher engagement were positively associated with students’ satisfaction (p<0.01). Conclusions 1. Among first-year basic health science students, satisfaction with the Anatomy course was influenced by teachers’ professional competence, ethics, interpersonal communication, and fair, objective assessment. 2. Adherence to professional ethics and maintaining respectful communication with students were found to be closely related to teachers’ knowledge and professional skills.

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by epidermal barrier dysfunction, immune dysregulation, and significant clinical burden. In Mongolia, research on AD has increased over the past decade; however, findings remain fragmented across various areas. Aim: To synthesize evidence from studies conducted in Mongolia over the last 10 years regarding the pathogenesis, clinical features, diagnosis, and treatment of atopic dermatitis. Materials and Methods: A narrative review was conducted, including original studies on Mongolian populations published within the last decade. Studies addressing skin barrier function, immunological mechanisms, genetic factors, environmental exposures, clinical severity, diagnostic tools, and treatment approaches were included. Results: The study findings show that genetic studies identified polymorphisms in the filaggrin gene and, more recently, mutations in the GCDH gene, suggesting these are linked to AD severity and allergen sensitization. Research on the immunopathogenesis of AD revealed that Th2-type cytokines, especially IL-3 and IL-4, are associated with pruritus and disease severity. Additionally, decreased skin hydration and increased transepidermal water loss in individuals with AD were linked to greater disease severity. Disease severity was evaluated using the SCORAD, EASI, and POEM tools, with most studies reporting that mild-to-moderate AD was most common. Clinically, symptoms like pruritus and sleep disturbances were evident. Additionally, clinical severity was associated with laboratory markers, particularly total IgE levels. The high rate of sensitization to inhalant and food allergens suggests that extrinsic atopic dermatitis (AD) may be common in the Mongolian population. In treatment studies using locally relevant natural products in Mongolia, such as seabuckthorn oil and Shargaljuut mineral spring spray, these products were associated with clinical improvement, suggesting they could serve as additional therapeutic options. Conclusion Research on atopic dermatitis in Mongolia has progressed in several areas; however, the current evidence remains limited and is mostly based on cross-sectional, small-sample, single-center, hospital-based studies. Therefore, there is a need for future comprehensive studies that are multicenter, long-term, and involve larger populations.

Background: HepG2 cells are widely used as an in vitro model for investigating alterations in hepatic cellular metabolism. Studies evaluating the biological activities of plant-derived compounds using HepG2 cells have also increased. Strawberry (Fragaria orientalis), lingonberry (Vaccinium vitis-idaea), radish (Raphanus sativus), and blue honeysuckle (Lonicera caerulea L.) contain polyphenols, flavonoids, anthocyanins, and other secondary metabolites. The biological activities of these plants may vary depending on species, plant tissue, growing conditions, and extraction methods. Prior to evaluating the biological activities of plant extracts, it is essential to assess their cytotoxic effects on cells and determine appropriate concentrations for subsequent experiments. Therefore, evaluating the effects of plant extracts on the viability of HepG2 cells, a human hepatocellular carcinoma cell line, is of considerable importance. Aim: To evaluate the effects of aqueous and ethanolic extracts of strawberry, lingonberry, radish, and cultivated and wild blue honeysuckle on HepG2 cell viability and to determine concentrations exhibiting cytotoxic effects. Materials and Methods: A total of 18 plant extracts were prepared using water and ethanol as extraction solvents. The extracts were obtained from strawberry leaves, lingonberry leaves, radish, and the fruits, stems, and leaves of cultivated and wild blue honeysuckle. The extracts were subsequently dried. HepG2 cells maintained in the Cell Biology Laboratory of the Institute of Biomedical Sciences were revived, stabilized, and used for the experiments. The plant extracts were prepared at concentrations of 6.25, 12.5, 25, 50, 100, 200, and 300 μg/mL and used to treat HepG2 cells. Cell viability was assessed using the Cell Counting Kit-8 (CCK-8) assay. Cytotoxicity was defined as a reduction in cell viability of more than 30% compared with the control group. Results: The aqueous extract of cultivated blue honeysuckle and the ethanolic extracts of its fruits and stems maintained HepG2 cell viability above 70% across the concentration range of 6.25–300 μg/mL, indicating relatively low cytotoxicity. In contrast, the ethanolic extract of cultivated blue honeysuckle leaves reduced cell viability at higher concentrations. The aqueous and ethanolic extracts of fruits and stems of wild blue honeysuckle showed no apparent cytotoxic effects, whereas both aqueous and ethanolic extracts of its leaves reduced cell viability to approximately 65% at 300 μg/mL, indicating relatively higher cytotoxicity. Most aqueous and ethanolic extracts of strawberry, radish, and lingonberry maintained cell viability above 70% and showed no cytotoxic effects. The ethanolic extract of strawberry leaves reduced cell viability to approximately 63% even at the lowest concentration of 6.25 μg/mL; however, cell viability tended to increase with increasing extract concentration. Conclusion The effects of plant extracts on HepG2 cell viability varied depending on plant species, tissue type, extraction solvent, and concentration. Most extracts of strawberry, lingonberry, radish, and the fruits and stems of cultivated and wild blue honeysuckle exhibited relatively low cytotoxicity at concentrations ranging from 6.25 to 300 μg/mL. However, the ethanolic extract of cultivated blue honeysuckle leaves at 200 μg/mL and the aqueous and ethanolic extracts of wild blue honeysuckle leaves at 300 μg/mL reduced cell viability by more than 30%, indicating relatively higher cytotoxicity.

Background: Currently, colorectal cancer (CRC) ranks as the third most common cancer and the second leading cause of cancer-related mortality worldwide. CRC frequently metastasizes to the liver (50%), lungs (10–15%), peritoneum (4%), bones (10.7%–23.7%), brain (0.3%–6%), and spinal cord. Approximately 35% of CRC cases are diagnosed before distant metastasis, 36% upon lymph node involvement, and 23% after distant organ metastasis. Although several studies have established primary tumor models in mice in our country, there are limited studies on experimental lung metastasis models, prompting the need for this research. Aim: To establish and evaluate a lung metastasis model of colorectal cancer in C57BL/6J mice using the MC38 cell line. Materials and Methods: This study was conducted at the Institute of Biomedical Sciences, Mongolian National University of Medical Sciences. Approval was obtained from the Ethics Review Board of the Mongolian National University of Medical Sciences (2023/3-09) and all laboratory safety regulations and protocols were strictly followed. Male C57BL/6J mice bred at the Experimental Animal Center of Mongolian National University of Medical Sciences were used. MC38 murine colorectal carcinoma cells were cultured and injected intravenously (via the tail vein) at a concentration of 0.25×10⁶ cells per mouse (n=12) to induce lung metastasis. Histological analysis was subsequently performed. Results: Histological examination revealed significant alterations in lung tissue architecture, characterized by areas of dense infiltration by pleomorphic, hyperchromatic cells, disrupting the normal alveolar structure. No histological abnormalities were observed in other organs. Conclusion Intravenous injection of MC38 colorectal adenocarcinoma cells into the tail vein of C57BL/6J mice successfully induced lung metastases, characterized by hyperchromatic, pleomorphic cell infiltrates forming glandular structures within the lung parenchyma.