Background: Copper is a mineral that is involved in many functions og the human body and copper has antibacterial reaction. However many scientists have studied the antibacterial activity of nano copper, in our country, the lack of research is the basis of our research. Aim: Determination of antibacterial activity of colloidal copper (CuNP) Materials and Methods: The study protocol was reviewed and approved by the Research Ethics Review Committee of the Mongolian National University of Medical Sciences on February 18, 2022 (Protocol No. 2022/3-02). An ionized copper solution was produced by passing an electric current (19–20 V, 3–5 A, for 24 h) through sterilized distilled water using copper plates. Ascorbic acid was then added to prepare colloidal copper. The concentration was determined using a PPM meter, and the solution was filtered through a 0.22 µm bacterial filter. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against standard bacterial strains were determined by the broth dilution method. To determine the bactericidal time, bacterial cultures were exposed to the bactericidal concentration and subcultured hourly for 10 hours. Additionally, antibacterial activity was evaluated on Mueller–Hinton agar using the disk diffusion method according to CLSI standards, where 20 µL of colloidal copper was applied onto antibiotic disks. The plates were incubated at 37°C for 24 hours, and the diameter of the inhibition zones was measured. Result: The concentration of the prepared colloidal copper was 0.7 ppm. Using the broth dilution method, complete bactericidal activity was observed at 0.006 ppm against Klebsiella pneumoniae, Escherichia coli, and Salmonella enteritidis, while Pseudomonas aeruginosa was completely killed at 0.008 ppm. In terms of exposure time, complete bacterial killing occurred after 2 hours for S. enteritidis and K. pneumoniae, after 6 hours for E. coli, and after 11 hours for P. aeruginosa. In addition, antibacterial activity was evaluated on Mueller–Hinton agar using the disk diffusion method according to CLSI standards. Colloidal copper increased the inhibition zone diameter of most antibiotics by 1–5 mm, particularly against P. aeruginosa. In K. pneumoniae, the activity of aztreonam and ceftriaxone was enhanced. When evaluating the inhibition zone diameter of cefotaxime against E. coli, the susceptibility result changed from intermediate to susceptible, while no significant change was observed for the other antibiotics tested. For K. pneumoniae, the addition of colloidal copper increased the inhibition zone diameter of aztreonam and ceftriaxone by approximately 1–2 mm. In P. aeruginosa, the inhibition zone diameters of most antibiotics increased by 1–5 mm; however, the activity of imipenem decreased. For S. enteritidis, most antibiotics showed an increase in susceptibility of approximately 1–2 mm, while ceftriaxone showed no observable effect. Conclusion 1. Colloidal copper solution, at low concentrations, exhibits bactericidal activity against some Gram-negative rod-shaped bacteria. 2. Colloidal copper solution shows a synergistic effect with certain drugs, enhancing their activity; however, it exhibits an inhibitory effect on the activity of imipenem.

Background: Globally, gastric cancer accounts for 1,089,000 new cases and 769,000 deaths annually, ranking fifth in overall cancer incidence and third in cancer-related mortality. The aim to determine HER2 expression in patients with gastric cancer and to evaluate its correlation with clinical and immunological biomarkers, as well as the need for further laboratory diagnostics. Aim: To determine HER2 expression in patients with gastric cancer and to evaluate its association with clinical and immunological biomarkers, as well as the potential need for further laboratory diagnostics. Materials and Methods: A retrospective study was conducted using archived materials from patients with gastric cancer at the Clinical Pathology, Molecular Genetics, and Pathology Laboratories of the National Cancer Center of Mongolia, covering the period from 2019 to June 2025. HER2 protein expression in tumor tissue was assessed using immunohistochemistry (IHC), and chromogenic in situ hybridization (CISH-HER2) was employed to confirm gene amplification. Statistical analysis was performed using the Prisma-10 software. Results: In our study, among 210 cases of gastric cancer evaluated by IHC for HER2, 46 (21.9%) were HER2-positive and 164 (78.1%) were HER2-negative. When comparing patients with gastric cancer stratified into HER2 1+ (negative) and HER2 3+ (positive) groups, no statistically significant differences (p < 0.05) were observed in age, sex, tumor location (surgically resected tissue), morphology, or disease stage. However, a higher proportion of males was noted in the HER2 3+ group (80.9%), though this did not reach statistical significance (p = 0.0879). Significant associations were found with tumor markers. Elevated serum CA-72-4 (>5 ng/mL) was more frequent in the HER2 3+ group (58.8%; p = 0.0069). In contrast, elevated CA-19-9 (>35 U/mL) was more common in the HER2 1+ group (93.5%; p = 0.0117), and elevated CEA (>6.9 U/mL) was also predominant in the HER2 1+ group (90.6%; p = 0.002). These findings suggest that HER2 3+ status predominates in cases with elevated CA-72-4, which may influence diagnostic strategies and HER2-targeted therapies (e.g., trastuzumab). Conversely, elevated CA-19-9 and CEA were more associated with HER2 1+ status, indicating a need for further detailed investigation of these markers in relation to HER2 expression. In patients evaluated by CISH for HER2 expression, stratification into HER2-positive and HER2-negative groups revealed no statistically significant differences (p < 0.05) in age, sex, tumor location, morphology, stage, or serum tumor markers (CA-72-4, CA-19-9, CEA). This suggests that HER2 status (positive/negative) may be independent of these variables. Although HER2 positivity was higher in poorly differentiated tumors (48% vs. 30.6% negative; p=0.1414) and in stage IV disease (50% vs. 39.3% negative; p=0.2607), these differences were not statistically significant. Elevated serum markers (CA-72-4, CA-19-9, CEA) were observed but showed no significant correlation with HER2 status. Conclusion Determining the molecular profile of gastric cancer patients can significantly contribute to refining clinical diagnosis, developing treatment strategies, enhancing therapeutic outcomes, and improving patients’ quality of life.

BACKGROUND OF STUDY: According to WHO report estimation, 76.3 million people have been diagnosed with disorder related to alcohol use which has been root cause for over 60 types of disease in the world.1 Smoking causes death to4 million people every year, 11 people every day and 6 every minute. This number is estimated to double reaching 10 million by 2030.2 The study conducted by the ‘World Vision Mongolia’ international organization and the Anti-alcoholism and Drug Association of the Ministry of Justice show 76% of all teenagers has drunk alcohol to some extent. AIMS: To determine alcohol, tobacco and psychoactive drug use by school teenagers of Sukhbaatar district in Ulaanbaatar MATERIAL AND METHODOLOGY: The survey on inquiry of alcohol, tobacco and psychoactive drug use (ASSIST) was conducted among a total of randomly selected 800 (374 boys, 426 girls) students of 8-12th grade from 7 secondary schools of Sukhbaatar district. Statistical data was put into Microsoft office applications (excel, word) and processed by SPSS application with 95% of probability of information and 5.0% of trust level. RESULT OF STUDY: Out of all respondents 32% (256) use tobacco, 43.8% (350)alcoholic drinks, 2.6% (21)cannabis,1.1% (9) cocaine, 1.5% (12) amphetamine, 3%(24)volatile substance, 4.3% (34)sedative and tranquilizer drug, 0.6% (5)hallucinogenic drug, 0.5% (4) opioid, and 0.1% (1) uses other types of drug. Among the survey participants, there are a total of 214 teenagers (in duplicated number) who need short-term action and 2 teenagers who are smoker and need intensive treatment. CONCLUSION: Among total teenagers, the survey participants, 1 in 3 used tobacco, 1 in 2 alcoholic drinks and 1 in 7 used psychoactive drug. Male students smoke twice more than female students and there is no difference in use of alcoholic drink in both sexes. The alcohol and tobacco use among teenagers at the age of 12-18 who participated in the survey showed that they use more when they grow older. 1 in 4 students of all participants belongs to a group with average risk and needs intensive treatment.

BACKGROUND: Toll like receptors (TLRs) are a class of proteins that key role in the innate immune system. TLR7 is expressed on monocytes, macrophages and dendritic cells, T cell, B cell and eosinophiles. TLR7, originally identified as recognizing imidaquinoline, loxibrine, broprimine and ssRNA, ssRNA viruses such as vesicular stomatitis virus, influenza A virus and human immunodefiency virus. It is known that virus ssRNA affects signaling molecule of IFN-y. Objective: To determine gene and protein activation of IFN-y signal transduction by TLR7 ligand in the endothelial cells. MATERIAL: In study we used mouse aortic linear endothelial cell which is cultured (END-D) in 5% heat- inactivated fetal calf serum (FCS), medium (DMEM) containing antibiotic mix(penicillin G, streptomycin, amphotericin B) at 37°C (5% CO2). Endothelial cells treated with synthetic IFN-γ and imiquimodligands, then the NO (nitric oxide) concentration in the supernatant is determined by Griess reagent. Endothelial cells are cultured in 6 well cell culture plate and in each well 2*104cells are expected to be grown for 24 hours of culture. Then, the cells are treated with synthetic IFN-γ and имиквимод ligand for 6 hours and the NO signaling gene activation iNOS mRNA expression which is induced by IFN-γ is determined by RT-qPCR. Endothelial cells are cultured in 12 well cell culture plate and in each well 2*104 cells are expected to be grown for 18 hours of culture. Then, the cells are treated with synthetic IFN-γ and imiquimodligands for 24 hours and the NO signaling protein iNOS expression which is induced by IFN-γ is determined by western blotting. The experiment was conducted as representation mean of at least three test results. The difference between statistical probabilities is determined by the “Students” t test. The p<0.01 value is assumed to be statistically different. RESULTS: TLR7 ligand imiquimodaugmented interferon gamma induced nitric oxide production TLR7 ligand imiquimodincreased interferon gamma induced iNOS mRNA gene expression. TLR7 ilgand imiquimodup-regulated interferon gamma induced iNOS protein expression. CONCLUSIONS: TLR7 ligand imiquimod augments IFN-γ signaling in the endothelial cells. This synergistic effect has revealed in the levels of gene and protein expression.