Aim: The aim of the study is to summarize the current knowledge on the causes of liver dysfunction in patients with rheumatoid arthritis (RA), with particular emphasis on viral infections, nonalcoholic fatty liver disease (NAFLD), autoimmune liver diseases, and treatment-related hepatotoxicity. Methods: A review of the literature published between 2015 and 2025 was conducted using PubMed and Google Scholar. Studies on hepatic complications in patients with RA were analyzed. Additional relevant studies were identified through reference screening, and selection was based on titles and abstracts. Results: In RA, liver dysfunction mainly reflects comorbid liver disease and metabolic risk rather than drug toxicity. NAFLD is the most frequent hepatic abnormality in RA, with a prevalence exceeding the general population, strongly associated with obesity, insulin resistance, and inflammatory activity. Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections remain clinically relevant due to their potential to mimic or modify RA manifestations and the risk of reactivation during immunosuppressive therapy. Autoimmune liver diseases occur less frequently, though primary biliary cholangitis (PBC) is reported more often in RA than in the general population. Methotrexate (MTX) most commonly causes transient, reversible enzyme abnormalities. Biological therapies and Janus kinase (JAK) inhibitors have varied liver safety profiles, with HBV reactivation in patients without adequate prophylaxis remaining a key concern. Conclusion: Liver dysfunction in RA reflects coexisting liver disease, chronic inflammation or immunogenetic predisposition. Safe long-term management requires regular liver function assessment, mandatory HBV and HCV screening, and identification of metabolic risk factors to minimize hepatic complications.

This article examines the role of international law in ensuring Mongolia’s national security from the perspective of small-state security policy. The contemporary international security environment is no longer limited to traditional military threats, border disputes, and armed conflict. It is increasingly shaped by multidimensional factors such as human rights, information and cyber domains, economic and energy security, environmental risks, migration, transnational crime, and hybrid threats. Under such conditions, the legal system for ensuring national security must develop not only within the scope of domestic legislation but also in close connection with the generally recognized principles and norms of international law, international treaties, multilateral institutional mechanisms, international courts and dispute settlement systems, and legal regimes relating to human rights and collective security. As a landlocked small state located between two great powers, with relatively limited demographic, economic, and material military resources, Mongolia has a particular need to use international law as a strategic instrument of national security. International law plays a crucial role in safeguarding Mongolia’s independence, sovereignty, territorial integrity, inviolability of borders, human rights, multi-pillared foreign policy, international cooperation, peace support operations, disarmament commitments, and nuclear-weapon-free status. The study applies document analysis, systemic legal analysis, comparative legal analysis, small-state security policy analysis, and theoretical synthesis of international law. The findings suggest that international law performs five key functions within Mongolia’s legal system for ensuring national security: first, a guarantee function for protecting independence, sovereignty, and territorial integrity, second, a normative function for strengthening human security, human rights, democratic governance, and the rule of law, third, a strategic function for supporting the external security of a small state through multilateral cooperation, international organizations, diplomacy, and legal mechanisms, fourth, a cooperation function for addressing non-traditional and transnational threats, and fifth, a regulatory function for guiding domestic legal and institutional reform. The article concludes that Mongolia needs to strengthen the incorporation of international legal norms into domestic legislation, assess the implementation of international treaties, enhance professional capacity in international law, introduce international legal risk analysis into national security policymaking, and increase Mongolia’s active contribution to the development and implementation of international law.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, and despite significant improvements in survival with intensive chemotherapy, relapse and minimal residual disease (MRD) remain major clinical challenges. Blinatumomab is a bispecific T-cell engager (BiTE) antibody targeting CD19-positive B-cell precursor ALL. By simultaneously binding CD3 on T lymphocytes and CD19 on leukemic cells, it enables major histocompatibility complex (MHC)-independent activation of cytotoxic T cells and targeted elimination of malignant cells. Clinical studies have demonstrated that blinatumomab is effective in inducing remission in relapsed or refractory pediatric ALL and in achieving molecular remission in MRD-positive patients. Compared with conventional chemotherapy, it shows improved efficacy and a more favorable toxicity profile, although cytokine release syndrome and neurotoxicity remain clinically relevant adverse events. Blinatumomab is increasingly used as a bridge to hematopoietic stem cell transplantation and is being investigated in combination regimens and earlier treatment settings. However, therapeutic resistance, including CD19 antigen loss and T-cell dysfunction, remains a limitation. Overall, blinatumomab represents a significant advancement in immunotherapy for pediatric ALL, bridging conventional chemotherapy and cellular therapies such as CAR-T.

Background: Traditional mathematical education primarily engages the verbal-phonological loop of working memory. This systematic review evaluates the cognitive impact of Abacus-Based Mental Calculation (AMC), a specialized mental arithmetic (MA) training that facilitates a transition from linguistic processing to a dynamic "mental blackboard" representational format. The study aims to characterize the causal relationship between systematic practice and the optimization of neurocognitive plasticity, fluid intelligence, and executive functions. Methods: A thematic synthesis was conducted on high-quality, peer-reviewed studies (primarily 2019–2026), including randomized controlled trials (RCTs) and longitudinal interventions involving children aged 6–12. The review integrates behavioral outcomes, such as standardized IQ scores (Raven’s Matrices), with neurobiological markers obtained via fMRI and Diffusion Tensor Imaging (DTI). Results: Evidence confirms that long-term MA training (12–24 months) induces significant "far-transfer" effects, notably enhancing fluid intelligence and visuospatial reasoning. Neuroimaging data reveal structural reorganization, including increased gray matter volume in the superior parietal lobule (SPL) and medial temporal lobe (MTL), alongside improved white matter integrity in the superior longitudinal fasciculus. Furthermore, experts demonstrate higher neural efficiency in prefrontal regions and enhanced specialized activation in the frontal pole (BA10) during executive tasks. Conclusion: Mental arithmetic serves as a powerful, low-cost cognitive technology that fundamentally reshapes the brain's functional architecture. The findings underscore the importance of intervention intensity, where sustained practice leads to permanent neurocognitive reorganization. Integrating MA into early childhood education offers a strategic framework for enhancing intellectual potential and fostering cognitive resilience in an information-dense world.

Peptide receptor radionuclide therapy (PRRT) has emerged as an established treatment option for selected patients with advanced somatostatin receptor (SSTR) – positive neuroendocrine neoplasms, particularly well – differentiated gastroenteropancreatic neuroendocrine tumors (GEP – NETs). In this setting, imaging is central not only to treatment selection, but also to biological risk stratification and post-treatment response evaluation. This structured narrative review examines the role of SSTR PET/CT, 18F – FDG PET/CT, and conventional cross – sectional imaging in PRRT candidate selection and response assessment. The literature search was performed in PubMed and focused on studies published from 2015 onward, with additional targeted identification of landmark clinical trials, consensus statements, and practice recommendations. Available evidence indicates that baseline SSTR PET/CT is essential for PRRT eligibility assessment, however, receptor positivity alone may be insufficient in biologically heterogeneous disease. In selected patients, particularly those with intermediate- or high-grade tumors, rapid progression, or discordance between clinical behavior and receptor imaging findings, 18F-FDG PET/CT provides complementary information on tumor aggressiveness and lesion-level heterogeneity. After PRRT, response assessment continues to rely predominantly on CT or MRI and RECIST 1.1, although this framework remains suboptimal in indolent, multifocal, bone-predominant, or mixed-response disease. Overall, current evidence supports a multimodal imaging strategy in which SSTR PET/CT remains the central theranostic tool, but is interpreted in conjunction with clinical context, cross-sectional imaging, and selective use of 18F-FDG PET/CT.

Childhood obesity represents a serious and steadily increasing global health problem, and early life feeding practices, particularly during infancy, may contribute to the subsequent development of obesity. Breastfeeding is regarded as the most appropriate method of infant feeding, and a growing body of evidence indicates that breastfeeding exerts a protective effect against overweight and obesity later in life. This article is based on a narrative review of the literature. Medical databases, including PubMed and Google Scholar, were systematically searched using the keywords breastfeeding, physical activity, exercise, obesity and adolescence. Due to heterogeneity in study designs and outcome measures, a quantitative meta-analysis was not performed. The available evidence suggests that engagement in physical activity during pregnancy and lactation does not adversely affect milk production, milk composition, or infant growth. A considerable body of research suggests that engagement in physical activity during lactation confers substantial health benefits to both the mother and the infant and may attenuate the risk of overweight and obesity in offspring later in life.

Background: Preterm infants, particularly those with very low birth weight (VLBW) and extremely low birth weight (ELBW), have substantially increased nutritional requirements. Although human milk provides many protective benefits, it does not fully meet the nutritional needs of this population, which justifies the routine use of human milk fortifiers. Traditionally used bovine milk–based fortifiers (BMBF) have raised concerns regarding their potential association with necrotizing enterocolitis (NEC), which led to the development of human milk–based fortifiers (HMBF). Objective: This narrative review aimed to present the current state of knowledge regarding the clinical benefits and limitations of HMBF in preterm infants, with particular emphasis on NEC, sepsis, growth, and mortality. Materials and Methods: A narrative literature review was conducted including randomized controlled trials, observational studies, and systematic reviews and meta-analyses comparing HMBF and BMBF in preterm infants. The analysis focused on clinically relevant outcomes, particularly in ELBW infants and in the context of an exclusive human milk diet. Results: The reviewed studies indicate a lower incidence of NEC among infants receiving HMBF, particularly within exclusively human milk–based diets. Mortality was also reported to be lower in some cohorts, particularly among ELBW infants. Rates of late-onset sepsis and other major morbidities were generally comparable between groups. Some studies reported slower short-term weight gain with HMBF, whereas long-term growth outcomes showed no consistent differences between feeding strategies. Conclusions: Current evidence suggests that HMBF may reduce the risk of NEC and mortality in highly vulnerable preterm infants, particularly those with ELBW. Although some studies report slower short-term weight gain, randomized trials have not demonstrated clinically meaningful differences in long-term growth or body composition. Overall, the potential clinical benefits appear to outweigh these temporary differences in growth velocity.

Background. Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition that frequently persists into adolescence and adulthood, affecting attention regulation, impulsivity, emotional control, sleep and overall functioning. In elite/competitive sport, these domains are tightly linked to training adherence, tactical decision-making, injury risk and recovery. Pharmacotherapy is one of the most effective evidence-based treatments for ADHD, yet in high-performance sport it must be implemented within additional constraints: potential cardiovascular and sleep-related adverse effects under heavy training load, elevated risk of non-medical use and diversion of prescription stimulants in athlete-adjacent environments and anti-doping regulations that may require a Therapeutic Use Exemption (TUE) for prohibited stimulant medications. Aim: To summarize evidence and practical guidance on pharmacological treatment of ADHD in elite/competitive athletes with specific focus on medication selection and monitoring under high training demands, TUE and anti-doping compliance, and prevention and management of stimulant misuse/diversion risk. Materials and Methods: A narrative literature review was conducted using a structured search strategy in PubMed/MEDLINE, supplemented by targeted retrieval of relevant World Anti-Doping Agency (WADA) TUE/ISTUE documents. The search covered the period from January 2011 to January 2026. The final search was executed on 16 February 2026. Eligible publications included original research, systematic reviews/meta-analyses, and regulatory guidance addressing ADHD pharmacotherapy, athlete contexts, TUE/anti-doping implications, and/or stimulant misuse/diversion. Results: The evidence supports that core pharmacotherapy principles for ADHD are broadly similar in athletes and non-athletes; however, elite sport requires additional implementation safeguards. Stimulants remain highly effective for symptom control but warrant careful monitoring of heart rate/blood pressure, sleep, appetite/energy availability, and anxiety—particularly during titration and high-load training periods. Non-stimulants (e.g., atomoxetine; selected cases guanfacine) may be appropriate when stimulants are not tolerated, contraindicated or when misuse/diversion risk is high. In tested sport, clinically necessary stimulant use often necessitates early, well-documented TUE planning to avoid inconsistencies between prescribing and regulatory submissions. Misuse and diversion are most commonly documented in young adult and collegiate settings, where sport-relevant drivers such as performance pressure, peer “sharing,” and weight-control motives may be present; this highlights the need for proactive education, secure storage, and structured follow-up. Conclusions: ADHD pharmacotherapy can be appropriate and beneficial in elite athletes, but it must be embedded in a sport-specific framework that integrates safety monitoring, stable competition-period planning, anti-doping/TUE documentation, and misuse/diversion risk mitigation. High-quality athlete-specific comparative studies - particularly stimulant versus non-stimulant strategies using objective outcomes - remain a key research priority.

Percutaneous coronary intervention (PCI) has become one of the most commonly performed cardiovascular procedures worldwide and represents a cornerstone therapy for the treatment of coronary artery disease and acute coronary syndromes. Over the past decades, significant technological and pharmacological advances have improved the safety and effectiveness of PCI procedures. Despite these developments, acute vascular complications remain an important clinical concern and may negatively affect procedural success and long-term outcomes. Acute complications associated with PCI include coronary artery dissection, coronary perforation, acute vessel closure, stent thrombosis, and bleeding events related to vascular access or antithrombotic therapy. Although the overall incidence of such complications has declined with the introduction of modern drug-eluting stents, intravascular imaging, and radial artery access techniques, the increasing complexity of treated coronary lesions continues to present challenges for interventional cardiologists. This review provides a comprehensive overview of the mechanisms, epidemiology, risk factors, prevention strategies, and management approaches for acute vascular complications following PCI. The analysis integrates findings from contemporary clinical trials, meta-analyses, international registries, and guideline documents. Particular attention is given to complications occurring during complex procedures such as chronic total occlusion interventions and treatment of heavily calcified coronary lesions. Understanding the mechanisms underlying PCI-related complications and implementing appropriate preventive strategies are essential for improving procedural safety and optimizing clinical outcomes in patients undergoing coronary revascularization.

Background: Sepsis is a life-threatening condition characterised by organ dysfunction caused by a dysregulated host response to infection and remains a major cause of morbidity and mortality worldwide. Early recognition is clinically challenging because initial symptoms are non-specific and commonly used inflammatory markers have limited diagnostic performance. Consequently, there is ongoing interest in biomarkers that enable faster and more accurate identification of sepsis. Aim: To discuss selected sepsis biomarkers: interleukin-6 (IL-6), soluble TREM-1 (sTREM-1), and neutrophil CD64 expression, with particular emphasis on biological mechanisms, clinical utility, and diagnostic limitations. Materials and methods: A narrative review of the literature was undertaken. Publications from 2016 to 2025 indexed in PubMed/MEDLINE, Scopus, and Google Scholar were analysed, including clinical studies, reviews, and meta-analyses. Evidence was assessed with respect to biological mechanisms, diagnostic and prognostic performance, and limitations of the biomarkers. Results: Neutrophil CD64 expression shows high specificity for bacterial infection and sepsis; however, routine use is constrained by limited assay standardisation and the absence of validated cut-off values. IL-6 rises very early and has prognostic value, correlating with the severity of organ dysfunction and mortality risk, but it has low specificity. sTREM-1 reflects activation of the TREM-1 axis and the intensity of the inflammatory response; however, its ability to distinguish sepsis from non-infectious SIRS is limited. Conclusions: None of the reviewed biomarkers should be used as a stand-alone diagnostic test. The greatest clinical value is likely to be achieved with a multiparametric approach that combines clinical assessment and organ dysfunction scores with biomarkers representing different stages of the immune response. This strategy may improve early recognition, risk stratification, and monitoring of sepsis.