Rationate: In recent years, global warming, climate change, environmental pollution driven by human activities, expansion of settlement areas, and mining operations within the Tuul river basin have been increasingly recognized as major factors affecting the river’s water quality, pollution levels, and flow regime [1, 3].
In particular, air and soil pollution in Ulaanbaatar, the quality and composition of effluent from the central wastewater treatment plant, water use by thermal power plants and boilers, as well as increasing domestic and industrial water consumption, continue to exert pressure on the Tuul river system [4, 6]. In addition, gold mining activities in the Zaamar area further contribute to the deterioration of water quality.
These combined pressures highlight the growing vulnerability of the Tuul river ecosystem and underline the need for detailed, spatially differentiated assessment of water quality along its course, especially within and downstream of urbanized areas. Objective: The objective of this study is to assess and evaluate the level of pollution in the Tuul river by spatially dividing the river into zones based on the results of chemical analysis. Materials and Methods: This study utilized water quality data obtained from laboratory analyses of Tuul River water samples conducted by the Information and Research Institute of Meteorology, Hydrology and Environment between 2022 and 2024. The data were accessed and used with official permission from the relevant authority.
The study was designed as a descriptive cross-sectional analysis. The research area was divided into three zones and 14 monitoring sites. A total of 373 water samples were analyzed based on 15 chemical parameters. Ethics: Before initiating the study, the research methodology and procedures were reviewed and approved by the Ethics Committee of Ach Medical University. An official request was submitted to the National Agency for Meteorology and Environmental Monitoring to obtain permission for the use of research data, and the data were used upon receiving approval.
To assess the water quality of the Tuul river, a statistical analysis was conducted on 15 key parameters across Zones 1, 2, and 3 using SPSS and Microsoft Excel. The study calculated arithmetic means and standard deviations to evaluate the data. A total of 373 samples, collected from 14 monitoring points within these three zones over a three-year period, were included in the analysis. Results: The three-year average concentrations of water quality indicators differed across Zones 1, 2, and 3. In Zones 2 and 3, key indicators including dissolved oxygen, biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonium nitrogen, mineral phosphorus, and chromium corresponded to Class IV and V levels of surface water quality classification, indicating heavy to extreme pollution. Conclusion
1. The chemical indicators reflecting the water quality and pollution level of the Tuul River show clear spatial variation along its course. The upper reach entering the city is relatively unpolluted, the central urban section experiences noticeable contamination, and the downstream section accumulates the highest level of pollution.
2. The main surface water pollution indicators in Zones 2 and 3 fall within heavily polluted (IV) and very heavily polluted (V) categories, indicating a strong influence of human activities and urbanization.
3. The average fluoride concentration in all zones exceeds the permissible limit defined by relevant standards by 2.5–3.9 times. Consumption of surface water with elevated fluoride levels may lead to fluorosis in humans, while livestock drinking water along the Tuul River may experience reduced productivity and disruption of normal bone structure development.

Introduction: Occupational diseases remain a significant public health concern, especially among workers exposed to hazardous environments such as the railway sector. Materials and Methods: A descriptive cross-sectional study design was employed using three official data sources, including national and institutional registries. Data were processed using Microsoft Excel and SPSS software. Ethical approval for this study was obtained from the Research Ethics Committee of “Ach” Medical University. Results: A total of 29 occupational disease cases were registered during the study period, of which 86.1% were male workers. The highest prevalence was observed in the 40–59 age group. Neurological disorders (51.7%) were the most common, followed by respiratory diseases and ear, nose, and throat disorders. A sharp increase in cases was observed in 2024, likely associated with improved detection and reporting systems. Conclusion:
1. The relatively high prevalence of occupational diseases among male workers aged 40 59 suggests a strong association with occupational conditions and workplace risk factors, indicating that prolonged exposure to hazardous working environments increases the risk of developing occupational diseases.
2. The relatively frequent occurrence of occupational diseases among locomotive drivers and repair workers is associated with physical, chemical, and ergonomic workplace risk factors.
3. The structure of occupational diseases is predominantly characterized by neurological disorders, respiratory diseases, ear, nose, and throat diseases, and occupational poisoning.

Background: Human papillomavirus (HPV) is the primary cause of cervical cancer, with HPV genotypes 16 and 18 classified as high-risk types. In Mongolia, HPV testing has been increasingly implemented in recent years, alongside updates to the national screening program. These developments highlight the need for additional testing approaches to encourage regular participation in the national screening program, improve diagnostic accuracy, and facilitate timely treatment planning. These considerations provided the rationale for this study. Aim: To detect HPV infection in cervical samples collected by healthcare professionals and vaginal samples self-collected by women, determine the concordance between the test results, and evaluate the feasibility of self-sampling for cervical cancer screening. Materials and Methods: A total of 206 women aged 25–68 years participated in the study. Two types of samples for HPV testing and one sample for PAP smear were collected from the participants. 14 high-risk of HPV genotypes were classified into three groups, and cytological findings were evaluated according to the 2014 Bethesda System. Statistical analyses were performed using SPSS version 30.0. Results: The concordance between the two sampling methods for HPV detection kappa was 0.949. High-risk HPV genotypes were detected in 50 women (35.2%) among the participants with available test results. Cytological abnormalities were identified in 51% of women who tested positive for HPV. Conclusion Self-sampling is a reliable method for HPV detection, demonstrating good concordance with healthcare professional-collected cervical samples. It has considerable potential to increase cervical cancer screening coverage and improve access to screening, particularly in geographically remote areas.

Background: The corneal endothelium, the innermost layer of the cornea, is composed of hexagonal cells that maintain corneal transparency and provide essential nutrients to the stroma. These cells play a critical role in preserving visual acuity. Previous studies have demonstrated that endothelial cells do not regenerate, and their density progressively declines with age, accompanied by morphological alterations. Given the individual variability in corneal thickness and endothelial morphology, establishing normative reference values is crucial for diagnosing corneal diseases, planning corneal transplantation, and optimizing surgical strategies for cataract surgery. However, there is a scarcity of data regarding central corneal thickness, endothelial cell density, and cell morphology among Mongolian adults. This knowledge gap provided the rationale for the present study. Aim: To study the central corneal thickness and endothelial cell morphology in Mongolian adults. Materials and Methods: This study was conducted using an analytical cross-sectional design. A total of 198 individuals aged 20 to 79 years were randomly selected, and comprehensive ophthalmic examinations were performed. Corneal parameters—including central corneal thickness, endothelial cell density, mean cell area, coefficient of variation of cell size, and the percentage of hexagonal cells—were quantitatively assessed using a non-contact specular microscope. Ethical approval was obtained from the Research Ethics Committee of the Mongolian National University of Medical Sciences (Approval No. 2024/3-06), and written informed consent was obtained from all participants prior to enrollment. Results: The mean age of the study participants was 48.4±14.5 years, with 48.9% (n=97) being male and 51.1% (n=101) female. In the central cornea, the mean endothelial cell density (ECD) was 2857.14±291.49 cells/mm², the mean central corneal thickness (CCT) was 526.25±33.67 µm, the mean cell area was 335.11±37.82 µm², the percentage of hexagonal cells was 64.81±3.94%, and the coefficient of variation (CV) in cell size was 0.31±0.04. With increasing age, both ECD and the percentage of hexagonal cells showed a statistically significant decline, while the mean cell area and CV demon strated a significant inverse correlation (P=0.0001). No statistically significant differences were observed in corneal thickness or endothelial morphometric parameters between the right and left eyes or between sexes. Among the Mongolian adults, the endothelial cell density decreases by approximately 0.3% annually (r=0.2107, p<0.0001). Conclusion 1. The mean central corneal thickness (CCT) in adult Mongolian individuals was 526.25±33.67 μm, which is comparable to reported averages from other populations. However, the mean endothelial cell density (ECD) was relatively higher, measured at 2857.14±291.49 cells/mm². 2. With advancing age, a progressive decline in central endothelial cell density and the proportion of hexagonal cells was observed, whereas the coefficient of variation (CV) in cell size and the mean cell area showed a corresponding increase

Background: Azoospermia is the most severe form of male infertility, affecting approximately 1% of male population and 10–15% of infertile men. In azoospermia cases, sperm retrieval from the testis or epididymis through surgical procedures is used for assisted reproductive treatments. When no sperm is retrieved, recent approaches in medicine suggest using immunohistochemical methods to evaluate spermatogenesis in testicular tissue and plan further treatments. Aim: To evaluate spermatogenesis in testicular tissue of azoospermic patients using immunohistochemistry and compare the findings with the clinical outcomes of sperm retrieval procedures. Materials and Methods: This study included 71 azoospermic men who underwent micro-TESE procedures at the IVF center (RMC) between 2019 and 2023. The excised testicular tissues were fixed, processed histologically, and evaluated using Johnson’s score. The presence of spermatozoa in seminiferous tubules was detected by immunohistochemical and immunofluorescence staining, using markers such as TEX101 and LDHC. Results: Johnson’s score was categorized into three groups: poor, moderate, and good spermatogenesis. These were statistically compared with hormonal levels and surgical sperm retrieval outcomes. There were significant differences in Johnson’s scores and serum FSH and LH levels among the three groups (p < 0.005). TEX101 and LDHC proteins were strongly expressed in the good group, weakly in the moderate group, and absent in the poor group. The success rate of sperm retrieval was 100% (17/17) in the good group, 96.29% (26/27) in the moderate group, and only 29.62% (8/27) in the poor group. Conclusion Histological evaluation of spermatogenesis in azoospermic patients can help predict the outcome of surgical sperm retrieval, indicating its clinical value in treatment planning.

Background: The development of accurate and non-invasive diagnostic tools is essential for improving early detection of cancers. Recent studies have shown that serum biomarkers may be useful for early detection of gastric cancer. Aim: We aimed to evaluate the diagnostic accuracy of PGI and PGR biomarkers for detection of the gastric cancer and atrophic gastritis. Materials and Methods: To identify relevant studies, the MEDLINE (PubMed) database was searched using the keywords (((“Gastritis, Atrophic”[Mesh]) OR “Stomach Neoplasms”[Mesh]) AND “Pepsinogen A”[Mesh]) AND “Sensitivity and Specificity”[Mesh]). Based on the inclusion and exclusion criterias, studies were selected according to the PRISMA guidelines. Meta-analysis was performed using Review Manager 5.4.1 and STATA/IC 15.0 (StataCorp LLC, USA, 2017). Results: According to the PRISMA guidelines, we selected a total of 18 studies in this meta-analysis. The meta-analysis results showed that the sensitivity of the PGI for the detection of atrophic gastritis was 58.5% (95% CI, 44.5-71.3), specificity was 90.2% (95% CI, 68.4-97.5), and DOR was 13.0 (95% CI, 2.6-64.6); the sensitivity of the PGR was 69.9% (95% CI, 58.1-79.5), specificity was 80.9% (95% CI, 52.4-94.2), and DOR was 9.8 (95% CI, 2.6-36.9). However, the sensitivity of the PGI biomarkers for detecting gastric cancer was 72.6% (95% CI, 54.7-85.3), specificity was 66.9% (95% CI, 52.5-78.7), DOR was 5.4 (95% CI, 3.1-9.3); PGR sensitivity was 77.8% (95% CI, 64.4-87.4), specificity was 65.0% (95% CI, 53.2-75.1), DOR was 6.6 (95% CI, 3.7-11.7); PGI+PGR sensitivity was 62.3% (95% CI, 51.1-72.2), specificity was 87.6% (95% CI, 78.0-93.3), DOR was 11.6 (95% CI, 6.8-19.8). Conclusion PGI and PGR tests demonstrated high specificity but moderate sensitivity. Although serum pepsinogen cannot replace endoscopy, it is considered to be an additional test and can be used to select high-risk populations.

Background: Gastroesophageal reflux disease (GERD) composes up to 28% of the esophageal disorders, and diagnosis of GERD is associated with a 10-15% of risk of Barrett’s esophagus, change of normal squamous epithelium of the distal esophagus to a columnar-lined intestinal metaplasia. It is reported that gastrointestinal (GI) disorders are the second out of five leading diseases in ambulatory diagnosed diseases and in 2022, esophageal adenocarcinoma is ranked in the fourth of the 10 most prevalent cancers among Mongolian population. When the Barrett’s esophagus changes shift to dysplasia, risk of esophageal adenocarcinoma development rises 30-125 folds and every year, 0.8% of population with dysplastic changes suffer from esophageal carcinoma. Although specific staining methods for histochemical analysis has been introduced into pathological laboratories detecting protein, fat, nucleic acid and enzymes that contained in cells, there isn’t study has been conducted to investigate the diagnostic specificity of Alcian blue and PAS staining method among population with Barrett’s esophagus. Aim: We aimed to make a differential diagnosis with basic and histochemical staining method in esophageal biopsies from Second Central Hospital of Mongolia (SCHM) and Mongolia-Japan hospital of MNUMS. Results: A total of 589 biopsies were collected from the SCHM and Mongolia-Japan Hospital of MNUMS and hematoxylin and eosin-stained results were Barret’s esophagus (43 biopsies or 7.3%), followed by Squamous cell carcinoma (46 or 7.8%), GERD (60 or 10.2%), hyperplastic polyp (92 or 15.6%), chronic erosive lesions (242 or 41%), polyp (94 or 15.9%), adenocarcinoma (12 or 2%), respectively. We have re-examined 43 cases with Barrett’s esophagus staining with Alcian blue and PAS and as a result, acidic mucin will be blue, neutral mucin will be purple, mixed mucin will be blue-purple and nucleus will be stained blue, respectively. Immunohistochemical re-staining of 43 biopsies with BE, Alcian blue were 87.8% and PAS were 97.4%. Conclusion Barrett›s esophagus, esophageal papilloma and hyperplastic polyps are comprising most of the esophageal precancerous disorders, and 9.8% of esophageal carcinoma was diagnosed. Histochemical re-staining of esophageal intestinal metaplastic changes is significantly beneficial to confirmation of the diagnosis.

Background: Multidrug-induced long QT syndrome is a serious heart rhythm disorder where multiple medications prolong the QT interval on an electrocardiogram, increasing the risk of a potentially fatal arrhythmia. Long QT syndrome is characterised by heart rate corrected QT interval prolongation and life-threatening arrhythmias, such as polymorphic ventricular tachycardia, Torsades de pointes leading to syncope and sudden death. Case: 21-year-old woman required resuscitation from an apparent cardiac arrest that had occurred after status epilepticus. The woman was diagnosed with long QT syndrome, cardiac channelopathy. She had a long history of syncope, seizure and palpitations. Family history was non-contributory. Home medications included levetiracetam 500 milligrams orally twice and fluoxetine 20 milligrams orally once a day which the patient reported non-compliance with. Levetiracetam is a widely used anti-epileptic medication secondary to its favorable safety profile. To our knowledge, there are few other case reports documenting torsades de pointes after levetiracetam administration, and specifically our case report will be the first documenting cardiac arrest after multidrug administration. Long QT syndrome is not often included in the differential diagnosis of epileptic and non-epileptic seizures. Early recognition of the syndrome is very important because of prognostic and therapeutic consequences. Conclusion Although no hereditary cause was confirmed, this case represents Torsades de Pointes triggered by multiple medications—including long-term low-dose carbamazepine, fluoxetine, diazepam, and high-dose levetiracetam—on a background of probable Romano–Ward syndrome or predisposition to QT prolongation. The arrhythmia progressed to cardiac arrest, requiring ICD implantation.

: Pleurotus ostreatus (Jacq) P. Kumm) is the second cultivated and most popular edible mushroom after Agaricus bisporus in the world. The fruiting bodies of these mushrooms have high nutritional value and are beneficial for health. Pleurotus ostreatus are an interesting source of bioactive glucans and other polysaccharides. This study focuses on the isolation and structural characterization of glucans from the fruiting bodies and stems cultivated mushrooms Pleurotus ostreatus. Methods: Physicochemical properties of fruiting bodies and stems cultivated Pleurotus ostreatus in Mongolia, were studied using standard methods. Glucans were extracted and purified using the precipitation method and Sevag reagent, and functional groups were determined by FT-IR. Conclusion The characteristic absorption bands of the water and alkali-soluble fractions were found near 1070, 1044, 869 and 777-769 cm-1. These IR bands are characteristic of fungal (1→3)(1→6)-β-D- glucans, and indicating these fractions are glucan-type polysaccharides

: Background: According to the statistics, Gastrointestinal disorders (GIDs) are the second of the leading five diseases among Mongolians, with an estimated 20% of GIDs by pathological diagnosis in 2022. Additionally, esophageal adenocarcinoma is ranked in the 4^th of the 10 most common cancer. Esophageal adenocarcinoma and its predispositions, and pathological changes are mostly located lower part of esophagus. Barret’s esophagus (BE) is consequences of goblet cell replaces the stratified squamous epithelium due to chronic gastroesophageal reflux disease. If BE transfers to the dysplasia, its probability of carcinogenesis is 30-125 times higher, and 0.8% of dysplastic patients with BE diagnosed with esophageal adenocarcinoma. Pathologists play a critical role in confirming the diagnosis of BE and BE-associated dysplasia. Goblet cells are almost always identifiable on routine hematoxylin and eosin-stained sections with Alcian blue (at pH 2.5). Purpose: To diagnose the esophageal biopsies via pathological immunohistochemical assay. Methods and materials: We investigated 130 biopsies in 2017-2019 years from NFCH, and 254 biopsies in SSCH. Result A total of 384 biopsies were collected from both national central hospitals and hematoxylin and eosin-stained results were Barret’s esophagus (50 biopsy or 13%), followed by dysplasia (66 or 17%), GERD (55 or 14%), squamous cell carcinoma (49 or 13%), chronic erosive lesions (41 or 11%), chronic esophagitis (40 or 10%), polyp (19 or 5%), adenocarcinoma (15 or 4%), acute esophageal erosion (5 or 1%), hyperplastic polyp (36 or 9%), and were others (8 or 2%), respectively.
As a result of immunohistochemical re staining of 50 biopsies with BE, Alcian blue were 87,8% and PAS were 97,4%.