Background: The World Health Organization has projected that by 2050, the global number of new cancer cases will reach 35 million [1]. In 2024, Mongolia ranks first in cancer mortality worldwide. As of 2024, Mongolia ranks 3rd globally for esophageal cancer with a rate of 19.8% per 100,000 people, and 1st for stomach cancer with a rate of 28.6% per 100,000 people [2]. In recent years, the number of new cases of esophageal and stomach cancers recorded in the population of Mongolia has been steadily increasing compared to other countries. According to statistical data in Mongolia, 8169 new cancer cases were registered in 2024, of which 4755 people died from cancer-related causes [3]. In 2024, 64.4% of cancer patients in Mongolia were diagnosed at a late stage, while only 35.6% were diagnosed at an early stage [4]. Compared to the previous year, early-stage cancer diagnosis increased by 65%, indicating an improvement in cancer detection. This progress is closely related to advancements in diagnostic methods. The development of medical technology, particularly the integration of advanced imaging features such as LCI (Linked Color Imaging) and BLI (Blue Light Imaging) into flexible endoscopy, has brought significant breakthroughs in endoscopic examinations [5]. Since 2023, the General Hospital of Khan-Uul District has been using the FUJINON 6000 model flexible endoscope from Japan, equipped with advanced imaging functions such as LCI (Linked Color Imaging) and BLI (Blue Light Imaging). The evaluation of the effectiveness of these technologies in accurately diagnosing early-stage cancers served as the basis for this study. Objective: The objective is to evaluate the accuracy of early-stage cancer detection using special light modes — LCI (Linked Color Imaging) and BLI (Blue Light Imaging) — among patients who underwent esophageal and gastric endoscopic examinations at the General Hospital of Khan-Uul District." Material and Method: In 2023 and 2024, a total of 4,842 patients underwent flexible endoscopic examinations of the esophagus and stomach at the General Hospital of Khan-Uul District. Among them, 82 patients with mucosal abnormalities or microvascular pattern changes in the esophagus, stomach, or small intestine were selected for retrospective analysis. Biopsies were obtained using advanced imaging technologies, specifically LCI (Linked Color Imaging) and BLI (Blue Light Imaging), to assess the diagnostic value of these modalities in detecting early neoplastic changes. Result: In 2023 and 2024, a total of 4,842 patients underwent flexible endoscopic examination of the esophagus and stomach at the General Hospital of Khan-Uul District. Among them, 82 patients with mucosal abnormalities were selected for further evaluation using LCI (Linked Color Imaging) and BLI (Blue Light Imaging), and biopsy samples were obtained. The findings were as follows:
• 18 cases of esophageal cancer were identified, of which 15 cases (83.3%) were early stage and 3 cases (16.6%) were advanced-stage.
• 26 cases of gastric cancer were detected, with 13 cases (50%) in the early stage and 13 cases (50%) in the advanced stage.
• 1 case of early-stage small intestinal cancer was also newly diagnosed.
All 28 early-stage cancer cases underwent endoscopic mucosal resection (EMR). The advantages of this procedure include minimal patient discomfort, no visible external wounds, low risk of bleeding or complications, and most importantly, organ preservation, which is a major clinical benefit. Conclusion LCI (Linked Color Imaging) and BLI (Blue Light Imaging) demonstrate greater accuracy in detecting mucosal abnormalities compared to conventional WLI (White Light Imaging) in the early diagnosis of esophageal and gastric cancers. Early detection of malignancies significantly improves patients’ quality of life and increases the 5-year survival rate to over 90%.

Background: Regularly participate international High-level in sports athletes national and competitions and engage in intense training, developing endurance and resilience. Measuring blood lactate levels is crucial for improving an athlete’s performance, assessing sports performance, and enhancing the effectiveness of future training. Aim: To study the relationship between lactate levels in the blood plasma and lactate dehydrogenase enzyme activity in Mongolian National Team athletes. Materials and Methods: The study involved 51 athletes from the Mongolian National Team. Anaerobic capacity was assessed using a Monark 894E Ergomedic Peak Bike, designed to apply exercise load. Blood serum lactate level and lactate dehydrogenase enzyme activity were determined using a Biobase BK-280 fully automated biochemical analyzer. Heart rate, peripheral blood oxygen levels, and oxygen saturation were measured using a pulse oximeter. Results: The average age of the participants was 24.04 ± 4.15 years, with an average height of 168 ± 8.78 cm and an average weight of 71.01 ± 7.69 kg. The average BMI was 24.82 ± 4.12 kg/m². Pre exercise lactate levels averaged 3.84 ± 0.75 mmol/L, while post-exercise lactate levels averaged 9.67±3.52 mmol/L. The average heart rate before exercise was 66.04±8.9 bpm, while post-exercise heart rate was 123.6±16.06 bpm. The average VO₂ max was 95.18±2.48. Conclusion The lactate levels before and after exercise among the athletes participating in the study showed significant differences in the age groups 20-29 (p<0.0001). When comparing lactate levels before and after exercise by sport, statistically significant increases were observed in freestyle wrestling and judo athletes (p<0.0001)

Background: According to the World Health Organization (WHO), 6.7 million people die annually due to air pollution caused by solid fuel use, with the majority of deaths resulting from respiratory diseases and cardiovascular conditions. In Mongolia, air pollution ranks as the fourth leading risk factor contributing to mortality, following hypertension, diabetes, and other major health risks. Although there have been numerous studies on outdoor air pollution in Mongolia, research linking indoor air pollution at the household level with the health status of residents remains limited. Aim: To compare indoor PM2.5 concentrations in households of Ulaanbaatar and Darkhan and examine their association with hypertension during the winter season. Materials and Methods: The study was conducted during November and December 2023, and January 2024, involving 240 households in Ulaanbaatar and Darkhan. Indoor PM2.5 concentrations were measured using Purple Air real-time sensors continuously for 24 hours over approximately one month. After measuring indoor air pollution, individuals aged 18–60 years living in the selected households were recruited based on specific inclusion criteria. Blood pressure was measured three times and the average value was recorded. Information on respiratory illnesses was collected through structured questionnaires. Statistical analysis was performed using STATA version 19.0. Results: A total of 241 households participated in the study, with 116 from Ulaanbaatar and 125 from Darkhan. Of the participants, 46.5% were male and 53.5% were female. In terms of housing type, 96 households (39.8%) lived in gers, 97 (40.2%) lived in stove-heated houses, and 48 (19.9%) lived in apartments. Among all participants, 66.0% (n=159) had hypertension and 34.0% (n=79) had normal blood pressure. Among participants aged over 40, 69.9–88.5% had hypertension, which is statistically significantly higher compared to younger individuals (p=0.0001). By body mass index, 75.3% (n=72) of overweight individuals and 78.4% (n=58) of obese participants had hypertension, showing a statistically significant difference compared to participants with normal weight (p=0.0001). The 24-hour average concentration of indoor PM2.5 was measured using the Purple Air device, and the levels in gers and stove-heated houses exceeded the limit set by the MNS 4585:2025 standard (37.5 µg/m³) Conclusion This study identified a relationship between environmental factors, such as air pollution and housing type, and the prevalence of hypertension. The indoor PM2.5 concentration in gers and stove-heated houses was above the standard limit, indicating a negative impact on the health of those residents. Furthermore, the high prevalence of hypertension among participants over the age of 40 and those who are overweight suggests a possible link to lifestyle and environmental conditions.

Background: Particulate matter with an aerodynamic diameter of 2.5 micrometers or smaller (PM2.5) penetrates deep into the alveoli through the respiratory tract and is characterized by its ability to induce oxidative stress, systemic inflammation, and vascular inflammation. Mongolia ranks among the countries with the highest levels of air pollution. In Ulaanbaatar, where more than half of the country’s population resides, wintertime PM2.5 concentrations often exceed 200 μg/m³, which is about eight times higher than the World Health Organization (WHO) guideline value. A study involving 1,200 adults in Ulaanbaatar showed that quality of life deteriorated sharply during periods of high air pollution, with effects more pronounced among individuals who already had impaired respiratory function. Aim: To examine the relationship between indoor household PM2.5 concentrations and lung function indicators among adults in Ulaanbaatar and Darkhan. Materials and Methods: This analytical cross-sectional study recruited adult participants from Ulaanbaatar and Darkhan through targeted sampling. Household air quality was measured using PurpleAir sensors, which were installed in participants’ homes for one month. After exposure measurement, lung function was assessed via spirometry. Statistical analyses were conducted using SPSS version 25.0. Results: A total of 236 participants were included: 114 (48.3%) from Ulaanbaatar and 122 (51.7%) from Darkhan. The sample consisted of 111 men (47.0%) and 125 women (53.0%). The mean indoor PM2.5 concentration was 66.24 μg/m³ (SD 44.87 μg/m³), ranging from a minimum of 7.79 μg/m³ to a maximum of 264.55 μg/m³. Stratification by housing type showed the highest PM2.5 levels in gers (82.34 μg/m³), followed by detached houses (67.34 μg/m³), while apartments had the lowest concentrations (32.24 μg/m³). Correlation analysis revealed statistically significant negative associations between PM2.5 levels and measures of expiratory function, including the FEV1/FVC ratio, peak expiratory flow (PEF), and mid-expiratory flow (FEF25–75). Reduced forced vital capacity (FVC) was observed in 9.4% of participants, reduced forced expiratory volume in one second (FEV1) in 15.3%, and a decreased FEV1/FVC ratio in 3.8%. Conclusion Indoor household PM2.5 concentrations were highest in gers, and expiratory flow-related lung function parameters showed significant negative associations with particulate exposure. This suggests that indoor PM2.5 primarily affects airflow limitation rather than overall lung volumes in this population.

Background: According to the World Health Organization (WHO), oral cancer is one of the most common malignancies of the head and neck region, ranking 16th among all cancers worldwide. Approximately 90% of oral cancers are oral squamous cell carcinomas. The development of this malignancy is influenced by multiple factors, and some genes plays a crucial role in development of the cancer. In recent years, the potential association between lncRNA GSEC and cancer has attracted significant research interest. Aim: This study aimed to investigate some functions of lncRNA GSEC in oral squamous cell carcinoma (OSCC) in vivo experimental model. Materials and Methods: To examine the role of GSEC in the proliferation of human oral cancer cells (CAL27), fifteen healthy 5-week-old BALB/c nude mice were divided into three groups: group Blank (CAL27 cells alone), NC (control si-NC CAL27 cells), and si-GSEC (si-GSEC CAL27 cells). The mice were subcutaneously injected with CAL27 cells alone, control si-NC CAL27 cells and si-GSEC CAL27 cells. Body weight and tumor size of the mice were measured throughout the experiment. On day 13, the mice were sacrificed, tumor tissues were excised and weighed, and the tumor tissues were stained using hematoxylin–eosin (HE) and immunohistochemistry to examine the expression of proliferation-related proteins Ki-67 and PCNA. Results: No significant differences in body weight were observed among the three groups of the mice up to day 13. However, the excised tumors from the si-GSEC CAL27 group were significantly smaller and lighter than those from the si- NC CAL27 and CAL27-only groups (p < 0.001). HE staining showed that tumor tissues in the si-GSEC group had more organized structure, better cellular differentiation, fewer malignant cells, decreased nuclear division, and reduced tumor transformation compared with the other groups. Immunohistochemical analysis revealed that Ki-67 and PCNA expression in tumor tissues was heterogeneously distributed, with higher density in peripheral and poorly differentiated regions, and lower expression in keratinized and necrotic areas. Notably, expression levels of both Ki-67 and PCNA were markedly reduced in the si-GSEC group compared with the other two groups. Conclusion lncRNA GSEC promotes tumor cell proliferation in vivo in oral squamous cell carcinoma.

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.

Background: According to the World Health Organization (WHO), 99 percent of the world’s population is exposed to air that exceeds WHO recommendations, with low- and middle-income countries being the most affected. The main causes of indoor air pollution include human activities such as fuel burning, cooking, cleaning, and smoking; housing characteristics such as walls, floors, ceilings, and furniture; ventilation; and outdoor air pollution. Aim : To assess PM1 and PM10 concentrations in 120 selected households in Ulaanbaatar. Materials and Methods : Indoor PM1 and PM10 concentrations were measured using Purple Air real-time sensors in randomly selected Ulaanbaatar households between October 2023 and January 2024. Supplementary data on factors affecting the PM2.5 concentration were collected via questionnaires. Each measurement was taken in 10-minute intervals, yielding 51,309 data for analysis. Results : PM1 concentrations were measured at 55.5±53.2 μg/m³ in gers, 54.9 ± 46.7 μg/m³ in houses, and 31.6±40.1 μg//m³ in apartments (p<0.001) and measuring PM10 concentrations were 110.6±108.6 μg/m³ in gers, 110.6±96.7 μg/m³ in houses, and 62.2±83.0 μg/m³ in apartments (p<0.001) When considering the concentration of PM1, PM10 by heating type, PM1 was 55.3±50.1 μg/m³ and PM10 was 110.6±103.0 μg/m³ in households with stoves and furnaces, and PM1 was 31.6±40.1 μg/m³ and PM10 was 62.2±83.0 μg/m³ in households connected to the central heating system (p<0.001). Regarding the months of measurement, the highest concentration was observed in December 2023, at 77.1±94.1 μg/m³. The highest concentrations for both PM₁ and PM₁₀ were recorded in January 2024, at PM₁: 64.8±55.1 μg/m³, PM₁₀: 131.4±116.0 μg/m³. Conclusion 1. Indoor PM10 concentrations in residential environments in Ulaanbaatar city were within the MNS4585:2016 Air Quality Standard, however, it was exceeded the WHO air quality guidelines, indicating an excessive risk of increasing morbidity and mortality among the population. 2. Indoor PM1 and PM10 concentrations in residential environments in Ulaanbaatar varies depending on location, type of housing, type of heating, and month of measurement.

Background: The first supposition of a possible relationship between occlusion and TMJ (temporomandibular joint) function was suggested by Costen, who hypothesized that changes in dental condition (loss of vertical dimension) can lead to symptoms of temporomandibular disorders (TMD). Symptoms of temporomandibular disorders are more common in women, with a female-to-male ratio ranging from 2:1 to 8:1. Temporomandibular disorders occur in 25-38% of the general population. The reason for conducting this study is that no research has been conducted in Mongolia on the relationship between malocclusion and TMJ. Aim: This study aimed to investigate the association between malocclusion and temporomandibular disorders. Materials and Methods: The study was conducted using a case-control design, and patients requiring orthodontic treat ment who visited the Orthodontics Department of the Center Hospital of the Dentistry, Mongolian National University of Medical Sciences were included in the case group, while relatively healthy individuals with normal occlusion who had not undergone orthodontic treatment were included in the control group. The sample size for each case and control group was calculated to be 20 people, for a total of 40 people aged 20-30. The need for orthodontic treatment was determined by the IOTN index (Index of Orthodontic Treatment Need). Relatively healthy occlusion was defined according to Andrew’s six keys. The condition of the temporomandibular joint was determined using a questionnaire and physical examination. Results: The mean age of the study participants was 24.4±3.7 years in the malocclusion group and 26.0±3.6 years in the control group, 45% (n=8) of the malocclusion group were male and 40% (n=9) of the control group were male. The indicators of malocclusion, such as increased overjet, decreased overjet, increased overbite and mouth breathing were statistically significantly different between the malocclusion group and the control group (p<0.05). Logistic regression analysis showed that CII (OR=11.66, p=0.007) and CIII (OR=16.33, p=0.017) occlusion, increased overbite (OR=6.87, p=0.025) and mouth breathing (OR=4.22, p=0.042) had an impact on the occurrence of TMJ noise in both vertical and horizontal directions. Conclusions 1. Among the study participants, Angle’s Class I accounted for 50% (the highest percentage), while Angle’s Class III accounted for 20% (the lowest percentage). But Angle’s Class II accounted for 30%. 2. Symptoms of temporomandibular joint disorder were statistically significantly higher in the case group (p<0.05). 3. People with Angle’s Class II and Class III were 11-16 times more likely to develop temporomandibular joint (TMJ) noise, a symptom of TMD, compared to people with normal occlusion.

Background: Class III malocclusion is considered to be one of the most difficult and complex orthodontic problems to treat. For patients whose orthodontic problems are so severe that neither growth modification nor camouflage offers solution, surgery to realign the jaws or reposition dentoalveolar segments is the only possible treatment option left. Aim: The treatment objectives were to: (1) level and align the dental arches; (2) obtain an ideal overbite and overjet, to establish correct anterior guidance; and (3) improve the facial profile. Case: Patient is present with skeletal Class III malocclusion, concave facial profile, facial proportion 0.96:1:1.04, loss of occlusion due to early molar teeth loss, molar and canine relationship were Class III, overbite 0 mm, overjet -1 mm, midline shifted into the 6 mm left side. Results: Excellent facial and occlusal results were achieved with this surgical-orthodontic management, post-treatment results showed a Class I relationship and ideal overjet and overbite. The facial profile became straight type. Conclusion This case report describes the treatment of a female with dental and skeletal class III relationships. Surgical- orthodontic treatment was the best option for achieving an acceptable occlusion and a good esthetic result in this case. An experienced multidisciplinary team approach ensures a satisfactory outcome.

Background: A 2018 study on the global burden of disease, accidents, and risk factors reported that 1.6 million peo ple died in 2017 due to household air pollution. Poor indoor air quality has been highlighted as a contributing factor to respiratory diseases, cardiovascular conditions, and exacerbation of asthma and allergies. A 2019 study estimated that long-term exposure to fine particulate matter (PM2.5) with a diameter of 2.5 micrometers or less reduces average life expectancy by 1.8 years, with more severe effects in highly polluted regions. Additionally, a study by Miller et al. (2007) found that prolonged exposure to PM2.5 increases the risk of cardiovascular diseases, particularly among women. Direct measurement devices are highly effective in determining indoor PM2.5 concentrations, identifying sources of pollution, tracking pollutant dispersion, and monitoring temporal variations. Studies suggest that direct measurement is an accurate, cost-effective method that provides detailed data suitable for local conditions. Aim: To investigate the indoor air quality of houses and apartments in Darkhan city during the winter season using the Purple Air monitoring device. Materials and Methods: A cross-sectional study was conducted with a targeted sample of 128 households in Darkhan city. The study examined factors such as stove type, type of coal used, annual and daily coal consumption, frequency of heating, and chimney sealing conditions. To collect data, the Purple Air monitoring device was installed in each house hold for a month, after which it was retrieved. During retrieval, participants completed a questionnaire. The questionnaire consisted of 55 questions across 7 pages at the time of device installation and 25 questions across 3 pages at the time of device retrieval. The collected data was analyzed using SPSS 25.0. Results: A total of 128 households in Darkhan city participated in the study. The average duration of residence in the current home was 9.5 years, with no statistically significant variation. The distribution of housing types was as follows: traditional Mongolian gers (40.6%), houses (39.1%), and apartments (20.3%). The 24-hour average PM2.5 concentration was highest in gers (70.9 μg/m³), followed by houses (46.8 μg/m³) and apartments (22.8 μg/m³), with a statistically significant difference (p=0.0001). PM2.5 levels were most variable in gers, followed by houses and then apartments. House holds using central heating (apartments) had an average 24-hour PM2.5 concentration of 22.8 μg/m³, whereas households using stoves (gers and houses) had a significantly higher concentration of 59.4 μg/m³ (p=0.0001). However, there was no statistically significant difference between traditional and improved stoves. Among study participants, 21.4% reported that someone in their household smoked indoors. Additionally, 86.5% regularly burned incense, candles, or herbs, while 99.2% did not use an air purifier. Conclusion The indoor particulate matter concentration in houses and gers in Darkhan was 59.4μг/m3. Variations in stove types, poor chimney sealing limited space, and frequent gaps and cracks contribute to increased spread of indoor air pollutants.