Background: Tuberculosis (TB) remains a major public health concern worldwide and continues to be a leading cause of morbidity and mortality. Delays in diagnosis and care seeking exacerbate disease severity and increase financial burdens on healthcare systems and patients. In Mongolia, comprehensive evidence on diagnostic delays and direct hospitalization costs for TB patients remains limited. Aim: To evaluate the duration of diagnostic delay and estimate direct medical costs incurred during hospitalization among TB patients, as well as to identify associated factors. Materials and Methods: A retrospective cross-sectional study was conducted using medical records of 285 newly diagnosed TB patients hospitalized at the National Center for Communicable Diseases (NCCD) in 2024. Statistical analyses were performed using SPSS version 26 and MS Excel. A p-value of <0.05 was considered statistically significant. Result: The mean age of participants was 42.6±16.0 years, and 56.5% (n=161) were male. Median patient delay was 14 days (IQR: 5–31), median diagnostic delay was 4 days (IQR: 0–14), and mean hospital stay was 21.0±16.0 days. Median direct costs per patient were: diagnostic cost 262.0 thousand MNT (IQR: 187.0–363.0), treatment cost 490.9 thousand MNT (IQR: 234.4–884.1), and total cost 761.7 thousand MNT (IQR: 460.4–1247.6). Multivariate linear regression revealed that patient delay >14 days was significantly associated with higher total costs (=659.333, p=0.004). Conclusion 1. The median patient delay among patients with tuberculosis was 14 days (IQR, 5–31), while the median diagnostic delay was 4 days (IQR, 0–14). Overall, 61.6% of patients experienced patient delay, and 63.5% experienced diagnostic delay. 2. The median total direct medical cost among hospitalized patients was 761.7 thousand Mongolian Tugriks (MNT). A patient delay of more than 14 days was significantly associated with increased total direct medical costs (β=659.333, P=.004).

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.

Backround: The university period is a unique phase in students’ lives, often marked by independent living, changes in lifestyle, diet, sleep patterns, increased psychological stress, and the development of unhealthy behaviors. Among students, particularly those studying in the medical field, research on dietary habits and influencing factors is scarce in our country, which serves as the rationale for this study. Aim: The aim of this study is to investigate the dietary habits of medical students and the factors influencing them, including sleep, impulsivity, depression, anxiety, and stress. Materials and Methods: A cross-sectional study was conducted among 358 students from years 1 to 6 across 7 schools of the Mongolian National University of Medical Sciences (MNUMS). Data were collected using internationally standardized and validated questionnaires, including the Three-Factor Eating Questionnaire Revised-18 (TFEQ-R18), the Short UPPS-P Impulsive Behavior Scale-20 (SUPPS-P-20), the Depression, Anxiety, and Stress Scale-21 (DASS-21), and the Pittsburgh Sleep Quality Index (PSQI). Statistical analysis was performed using SPSS 25.0. Results: In terms of eating behavior, uncontrolled eating (UE) and cognitive restraint (CR) were similar between male and female students, while emotional eating (EE) was more prevalent among male students. Students’ eating behaviors were associated with body mass index (BMI). As BMI increased, levels of depression, anxiety, and stress also tended to rise. Sensation-seeking and positive urgency were higher among female students. Overall, 83.5% of students had poor sleep quality, which contributed to increased depression, anxiety, stress, and impulsivity. Psychological burden and impulsivity were independent of the field of study but decreased as students progressed through their academic years, while sleep quality improved. Conclusion The dietary habits of medical students were similar across genders but varied by academic year and field of study. Poor sleep quality, observed in 83.5% of students, was associated with increased depression, anxiety, stress, and impulsivity. Psychological burden and impulsivity were unrelated to the field of study but decreased with advancing academic years, alongside improved sleep quality. As BMI increased, cognitive restraint in eating behaviors decreased.

Background: According to the World Health Organization (WHO), the shortage of human resources in the healthcare sector has shown a growing trend year by year. Notably, there is a significant shortage, inadequate distribution, and high turnover of licensed professionals, influenced by various factors. Aim: This study aimed to examine healthcare workers’ turnover intentions and the influencing factors in referral healthcare organizations in Ulaanbaatar city. Materials and Methods: The study employed a cross-sectional study using quantitative research methods was conducted during 2024–2025. A total of 150 healthcare workers from central hospitals, maternity hospitals, and district health centers participated. The standardized questionnaire developed by Auerbach et al. (2013) was used to assess turnover intention. Data were analyzed using SPSS 26.0 software. Results: Of the participants, 38% were from central hospitals, 33.3% from maternity hospitals, and 28.6% from district health centers. The majority (85.3%) were female. In terms of profession, 44.6% were doctors, 34.6% nurses, and 20.6% comprised paramedics, public health specialists, laboratory physicians, pharmacists, and midwives. Regarding retention, 78% of participants intended to continue working in the healthcare sector until retirement, while 35.3% expressed an intention to leave in the near future. Statistically significant differences in turnover intention were observed by age and profession. Younger employees demonstrated a higher intention to leave, whereas middle-aged employees with longer work experience showed greater stability within the healthcare sector. Additionally, 76% of participants emphasized salary and incentives, 68% workplace atmosphere, and 73.3% opportunities for career advancement as key factors influencing job retention. Conclusion The study revealed that one in five healthcare workers intends to leave the healthcare sector, while one in four is considering leaving their current organization. Turnover intention varied significantly by age and profession.

Background: Vitamins are nutrients essential for human health. They act as coenzymes that help trigger important chemical reactions necessary for energy production. Reference values for vitamins help physicians evaluate the health status of patients and make clinical decisions. The aim of this study was to determine the mean values and reference intervals for some water-soluble vitamins of Mongolian adults. Materials and Methods: Three hundred and forty healthy adults (170 males and 170 females) of 17 to 69 years of age were selected for the study based on CLSI C28-P3 criteria Defining, establishing & Verifying reference interval in the clinical laboratory; Proposed Guidelines. The study was approved by the Resolution No.76 of 2018 of the Medical Ethics Review Committee of the Ministry of Health. Informed consents were taken from the selected individuals. Morning blood samples of the participants were collected under aseptic conditions. Levels of vitamins B₆, B₉, B₁₂ and vitamin C were measured using a high performance liquid chromatography method. The lower- and upper reference limits were defined as the 2.5th and 97.5th percentiles, respectively. The data were analyzed using SPSS and Excel programs. Results: The mean blood level of vitamin C was 11.88 mg/L (95% CI 10.47-13.29) for men and 9.62 mg/L (95% CI 8.11-11.13) for women. The calculated reference interval for males was 1.40-19.40 mg/L and 1.17-18.04 mg/L for females. The mean concentration of vitamin B₁₂ in the blood of males was 938.45 ng/L (95% CI 747.22-1129.68) and that of females was 864.03 ng/L (95% CI 603.81-1124.25). The reference interval for vitamin B₁₂ was 233.03-1597.00 ng/L in men and 132.45-1623.86 ng/L in women. The mean level of vitamin B₉ was 8.47 ng/mL (95% CI 5.64-11.30) for men and 6.91 ng/mL (95% CI 4.89-8.93) for women. The calculated reference interval for this vitamin in males was 1.04-24.74 ng/mL and that in females was 1.04-21.46 ng/mL. As for vitamin B₆, the mean concentration for men was 44.42 ng/mL (95% CI 37.01-51.83) and for women was 34.67 ng/mL (95% CI 29.97-39.39) with the reference intervals of 5.90-79.02 ng/mL for men and 5.27-61.72 ng/mL for women. Conclusion The reference values for vitamins B₆, B₉, B₁₂ and vitamin C of Mongolian adults do not differ significantly from those observed in other populations. The calculated reference intervals can be used in the practice of health laboratories.

Background: Soil pollution in Ulaanbaatar has increased in recent years, causing infectious and non-communicable diseases, both benign and malignant.
Therefore, in order to reduce soil pollution, it is necessary to isolate strains resistant to heavy metals and use these microorganisms capable to degrade or accumulate heavy metals for bioremediation purposes. Methods: Bacterial pure cultures were isolated from soil and water samples and incubated in a Nutrient Broth medium with a lead concentration of 1000 mg/L in a thermostat with a shaker at 37°C. The growth rate was determined at a wavelength of 600 nm using a Spectrophotometer. Results: In total 69 pure cultures were isolated from the soil samples and 65 pure cultures from them were able to grow at the concentration of lead of 1 mmol/L. 4 pure cultures (UBLF1, UBLF3, UBMF2, and SUBZ4) were able tolerate lead concentrations up to 8 mM. These cultures were determined by semi-automatic VITEK®2 analyzers and identified as Bacillus sp. (83%) and UBMF2 identified as Bacillus thuringiensis (93%) respectively. Conclusion The lead content in water samples were found to be acceptable, and isolated pure cultures were not able to withstand the lead concentrations.
Pure culture UBLF3 isolated from the soil capable to reduce lead concentration (500 mg/L) up to 302 mg/L and 230 mg/L in the medium, and pure culture UBMF2 up to 340 mg/L and 279 mg/L respectively

Introduction: Researchers have found that people living in polluted areas have a lower ability to resist skin bacteria and increase the number of skin microflora. Decreased immune function increases the risk of sore throat, influenza, respiratory infections, pneumonia and gastrointestinal diseases. One of the main indicators of the human immune system is the normal microflora. Goal: To study the relationship between normal human microflora and specific immunity. Material and Methods: This study was conducted within the framework of the project “Effects of non-specific immune factors on injectable infectious disease immune system”. The survey sampled 10 households from Dornod aimag, 8th khoroo of Chingeltei district, Ulaanbaatar city, and 3rd khoroo of Baganuur district. A total of 176 people aged 6 months to 50 years were involved. A total of 528 swab samples and 31 blood samples were collected from the throat, tonsils, skin and mucous membranes to study the relationship between normal human microflora and specific immunity.
The research methodology was discussed at the meeting of the Academic Council of the Ministry of Social Welfare and the Medical Ethics Review Committee under the Ministry of Health (January 5, 2018, Resolution 646) and the research was approved. Results: The total number of normal microorganisms in the skin and mucous membranes of the study participants changed, and the number of hemolytic strains and fungi increased. 58%-67% of the participants had normal and long-term immunity against diphtheria and tetanus, while 5% -14% were not. This result was as high as in urban and rural areas. Conclusion This result was as high as in urban and rural areas. As the age group increases, the level of the body’s specific immunity decreases, the structure of the normal microflora changes, and the number of fungi and hemolytic bacteria increases. Furthermore, it is necessary to study specific and nonspecific immunity in detail in relation to environmental pollution indicators.

Background: Minerals are important for the proper body functioning. They also play a role in preventing and fighting diseases. Reference values for minerals help physicians evaluate the mineral status of patients and make clinical decisions. The aim of this study was to determine the mean values and reference intervals for some minerals to be used for evaluation of the nutrition status of Mongolians. Materials and Methods: Two hundred and forty healthy adults (120 males and 120 females) of 17 to 70 years of age were selected for the study based on CLSI C28-P3 criteria Defining, establishing & Verifying reference interval in the clinical laboratory; Proposed Guidelines. The study was approved by the ethical committee of the Ministry of Health of Mongolia. Informed consents were taken from the selected individuals. Morning blood samples of the participants were collected under aseptic conditions. Levels of iron (Fe), zinc (Zn) and copper (Cu) were measured by graphite furnace atomic absorption spectrometry. The lower and upper reference limits were defined as the 2.5th and 97.5th percentiles, respectively. The data were analyzed using SPSS and Excel programs. Results: The mean level of blood iron was 30.50 µmol/L (95% CI 29.71-31.29) for men and 30.91 µmol/L (95% CI 30.03-31.79) for women. The calculated reference interval for males was 21.39-37.72 µmol/L and 19.87-39.67 µmol/L for females. The mean concentration of zinc in the blood of males was 11.00 µmol/L (95% CI 10.69-11.31) and that of females was 11.79 µmol/L (95% CI 11.39-12.19). The reference interval for blood zinc was 8.20-14.92 µmol/L in men and 8.52-16.67 µmol/L in women. The mean level of blood copper was 15.28 µmol/L (95% CI 14.64-15.89) for men and 18.08 µmol/L (95% CI 17.30-18.86) for women. The calculated reference interval for copper in males was 9.72-22.34 µmol/L and that in females was 11.18-27.27 µmol/L. Conclusion The reference values for zinc, copper and iron of Mongolian adults do not differ significantly from those observed in other countries. The calculated reference intervals can be used for evaluation of the nutrition status and making clinical decisions.

Background: Reference values are very important for the clinical decisions in laboratory diagnosis and clinical management of patients. Method: A total of 340 adults (apparently healthy individuals) between 18 to 70 years resident in the Ulaanbaatar city were randomly selected and enrolled in this survey. 340 adults made up of 170 males, 170 females were assessed by a clinician to be healthy. About 5 ml of blood was collected with EDTA test tube and analyzed using automated analyser to enumerate the hematological parameters (red blood cell, white blood cell, hemoglobin and haematocrit). Reference values were determined at 2.5^th and 97.5^th percentiles. Results: Reference values estabilished include: red blood cell 4.69-6.04×1012/L, white blood cell 3.98-9.11×109/L, haemoglobin 145-176 g/L, haematocrit 42.6-52.9% for males and red blood cell 4.10-5.20×1012/L, white blood cell 3.50-9.08×109/L, haemoglobin 121.8-148.2 g/L, haematocrit 36-44.7% for females. Conclusion We were determined mean and reference range of haematological parameters (red blood cell, white blood cell, haemoglobin, haemotocrit) which are important for assessing the nutritional status of adults according to the international standard methodology. The international reference range shows that white blood cells counts do not indicate gender and our data (р=0.0964 are statistically insignificant) also offers no significant difference was found between samples for male and female subjects.

Background: We set the average value and reference range of blood plasma proteins (total protein, albumin, transferrin, retinol binding protein, prealbumin) to be used to assess the nutritional status of Mongolian adult. According to step by step research methodology, 170 women, 170 men and a total of 340 people were surveyed using a combination of questionnaires and analytic methods. Methods: The total protein and albumin content of the collected samples was analyzed by colorimetric method using “Humalyzer 2000” semi automatic analyzer and prealbumin, transferring and retinol binding protein was analyzed by ELISA method of “ELX 880”. The lower limit of the reference value of the identified parameters was calculated to be 2.5 per centil and the upper limit was 97.5 per centil. Results: Determining average and reference range of proteins in the plasma of a total 340 participants, the average of total protein was 74.54(CI 95%; 72.67-76.38) g/l for men, and 73.59(CI 95%; 72.39-74.79) g/l for women, while the reference range was 55.26-95.79 g/l for men and 58.38-84.72 g/l for women. According to determined above, there is no statistically significant difference in gender (p>0.40). The average albumin level is 48.20(CI 95%; 47.04-49.36) g/l for men and 46.28(CI 95%; 45.32-47.24) g/l for women, while reference range is 37.14-60.01 g/l for men and 34.97-57.60 g/l for women. It means there is a statistically significant difference for the gender (p=0.012). The average prealbum level is 332.43(CI 95%; 311.28-353.58) mg/l for men, 381.67(CI 95%; 360.98-402.36) mg/l for women, while reference range is 171.3-485.0 mg/l for men and 215.5-535.0 mg/l for women. It means there is a statistically significant difference for the gender (p=0.0012). The average range of transferrin 4.01(CI 95%; 3.76-4.26) g/l for men and 4.43(CI 95%; 4.20-4.66) g/l for women while reference range is 2.20-6.92 g/l for men and 2.58-7.05 g/l for women, is a statistically significant difference for the gender (p=0.017). The average level of retinol binding protein is 1.73(CI 95%; 1.61-1.85) μmol/l for men and 2.01(CI 95%; 1.89-2.13) μmol/l for women, while reference range is 0.73-3.08 μmol/l for men and 0.73-3.08 μmol/l for women, is a statistically significant difference for the gender (p=0.0017). Conclusions For the first time we conducted a study to determine the average amount and reference range of proteins needed to assess the nutritional status of adults (total protein, albumin, prealbumin, transferring, retinol binding protein) according to international standard methods, which is relatively high compared to other researchers. According to the result of the study, it is not possible to directly follow the result of researchers from other countries and the reference range of blood proteins directly to Mongolians. The result of this study has become an important innovation in practice and treatment, as medical professionals have been able to use it in their diagnosis and treatment.