Vol 32, No 1 (2026)

BACKGROUND: Serum immunoglobulin A (IgA) concentration is an important yet controversial marker of immune status in athletes. Data on its concentration the off-season and the influence of factors such as the level of physical contact and the individual/team nature of the sport are scarce.

AIM: To evaluate the combined effect of the level of physical contact (contact vs low-contact) and sport modality (individual vs team) on serum IgA concentration in elite athletes during the off-season period.

METHODS: A retrospective, cross-sectional study was conducted using anonymized data from 12,317 Russian national team athletes in boxing, tennis, basketball, and volleyball from 2012–2020. Groups were formed using a 2×2 factorial design: "contact" (boxing, basketball) vs "low-contact" (tennis, volleyball) and "individual" (boxing, tennis) vs "team" (basketball, volleyball) modality.

RESULTS: Statistically significant differences were found in the median serum IgA concentrations, with all values remaining within the reference range. Athletes in contact sports (basketball: 1.81 g/L; boxing: 1.72 g/L) had significantly higher IgA levels than athletes in low-contact disciplines (volleyball: 1.57 g/L; tennis: 1.55 g/L). The factor analysis mathematically confirmed the existence of two independent constructs differentiated on the basis of physical contact. No significant effect of sport modality (individual/team) or factor interaction was observed.

CONCLUSION: In the inter-competitive phase, the degree of physical contact acts as a key determinant modulating basal serum IgA within physiological limits, with elevated concentrations observed in contact sport athletes. The practical significance of these findings lies in the necessity of a sport-specific approach to immunological monitoring: the lower bound of the reference range considered normal for low-contact disciplines may be inadequate for athletes practicing contact-intensive sports.

BACKGROUND: Identifying predictors of mortality risk in patients receiving hemodialysis in the medium term enables the development of measures aimed at reducing this risk. However, data obtained from different dialysis centers may be highly heterogeneous, which reduces the reliability of the resulting estimates. In such cases, statistical tools for aggregating results, traditionally used in meta-analyses, may be helpful. This approach can substantially increase confidence in the findings.

AIM: To identify predictors of mortality risk in patients receiving maintenance renal replacement therapy in the medium term, with adjustment for data heterogeneity in a multicenter study.

METHODS: The study included data from a retrospective, continuous November 1, 2017, to April 30, 2020, involving patients aged ≥18 years who had been receiving outpatient maintenance hemodialysis for at least 3 months and had a functioning vascular access. Censoring criteria included transition to peritoneal dialysis or kidney transplantation during the 30-month follow-up period. At the first stage, hierarchical Bayesian Cox proportional hazards models were estimated separately for four clusters of dialysis centers formed territorially. At the second stage, significant predictors of survival were selected, and generalizing models with fixed or random effects were estimated for these predictors (models were selected based on Cochran’s Q test).

RESULTS: Retrospective data over 2.5 years were collected for 2120 patients who met the inclusion and exclusion criteria across 30 dialysis centers. Over the 30-month follow-up, 468 patients died (22.08%); 7 patients (0.33%) were transferred to peritoneal dialysis (all in Ufa); and 42 patients (1.98%) underwent kidney allotransplantation. The analysis demonstrated that only patient age was a risk factor for mortality (hazards ratio [HR], 1.02; 95% confidence interval [CI], 1.01–1.03). All other factors were associated with a reduced risk of death as their values increased: duration of dialysis therapy (HR, 0.95; 95% CI, 0.92–0.99), body mass index (HR, 0.93; 95% CI, 0.87–1), duration of anti-anemic therapy in months (HR, 0.91; 95% CI, 0.86–0.97), and duration of therapy aimed at correction of calcium–phosphate metabolism in months (HR, 0.94; 95% CI, 0.92–0.96). The mean single-pool (sp) ratio of dialyzer urea clearance (K) multiplied by dialysis time (t) to the volume of urea distribution in the patient’s body (V) (spKt/V) showed no significant association with mortality risk: although the HR was 0.35, the CI was very wide (0.08–1.57), indicating that an increase in spKt/V was associated with a reduced risk of death in some patients and an increased risk in others.

CONCLUSION: Based on preliminary differences in survival among dialysis patients, four clusters belonging to different constituent entities of the Russian Federation were identified. An approach that aggregates modeling results across territorially defined clusters of dialysis centers resulted in greater confidence in the estimated survival outcomes of patients receiving outpatient maintenance hemodialysis.

Propionic acidemia is a rare inherited metabolic disorder associated with impaired function of propionyl-CoA carboxylase, encoded by the PCCA and PCCB genes. Despite the inclusion of propionic acidemia in international neonatal screening programs, cases of delayed diagnosis continue to occur, particularly in countries where population-based screening does not cover the full spectrum of metabolic disorders. The clinical manifestations of propionic acidemia may mimic common somatic or surgical conditions, which complicates timely diagnosis and increases the risk of an unfavorable course. The present report describes a case of successful diagnosis and management of propionic acidemia in a newborn whose initial clinical presentation was interpreted as a gastrointestinal condition.

During the first month of life, the patient exhibited frequent regurgitation, poor appetite, failure to gain weight, as well as episodes of lethargy and tremor, prompting evaluation for pyloric stenosis and other gastrointestinal disorders. However, further biochemical and instrumental investigations revealed elevated propionylcarnitine (C3) levels, increased propionylcarnitine-to-acetylcarnitine (C3/C2) and propionylcarnitine-to-palmitoylcarnitine (C3/C16) ratios, raising suspicion of an organic acidemia. Whole-exome sequencing identified compound heterozygous variants of uncertain clinical significance in the PCCA gene: c.734C>T (p.Ser245Leu) and c.1351A>G (p.Lys451Glu). Sequencing of the unaffected parents and sibling confirmed heterozygous carrier status: c.734C>T (p.Ser245Leu) in the father, c.1351A>G (p.Lys451Glu) in the mother, and c.1351A>G (p.Lys451Glu) in the sister. The diagnosis of propionic acidemia was established based on the totality of clinical, biochemical, and genetic findings. Appropriate therapy, including a specialized amino acid-restricted diet, carnitine and biotin supplementation, hydration, and symptomatic management, was initiated. Following treatment, the patient’s condition stabilized, and at 7 months of age, development was consistent, with no neurological impairment.

This clinical case highlights the importance of early diagnosis of propionic acidemia and underscores the role of tandem mass spectrometry in neonatal screening. Despite nonspecific initial symptoms, heightened clinical awareness and a comprehensive diagnostic approach allow for diagnosis before the development of irreversible complications. The case demonstrates the diagnostic value of integrating biochemical and molecular methods and emphasizes the need for a multidisciplinary approach.

Central serous chorioretinopathy is characterized by focal dysfunction of the retinal pigment epithelium associated with choroidal vascular hyperpermeability, which causes subretinal fluid to accumulate and serous detachment of the neurosensory retina to form, accompanied by detachments, defects, or other alterations of the retinal pigment epithelium. Optical coherence tomography (OCT) and OCT angiography are indispensable in central serous chorioretinopathy for diagnostic verification, exclusion of complications, determination of management strategies, and subsequent patient monitoring.

Based on the conducted exploratory and analytical review, it should be noted that, despite the large body of research on OCT diagnostics in central serous chorioretinopathy, many issues remain insufficiently investigated. In particular, further clarification is required regarding the criteria for distinguishing acute and chronic disease courses, the capabilities of OCT for verification of presumed leakage areas, and its role in detecting choroidal neovascularization. Further research is also necessary to refine the criteria for disease progression, recurrence, positive and negative treatment response, and the development of complications.

To structure the data on diagnostic and management approaches to central serous chorioretinopathy, the investigation of OCT biomarkers appears especially relevant. Owing to numerous clinical studies in recent years, the potential clinical applications of OCT biomarkers in central serous chorioretinopathy have expanded. OCT biomarkers of recurrence, as well as predictive and prognostic OCT biomarkers of favorable and unfavorable disease outcomes, have been identified. Thus, the primary clinical value of OCT biomarkers lies in their ability to support individualized patient management, enabling a personalized approach to treatment based on the specific characteristics of disease course.

This review examines contemporary strategies of cardiorespiratory monitoring and predictors of complications in abdominal and thoracic surgery. The relevance of this topic is driven by the high incidence of perioperative cardiorespiratory complications, which substantially worsen clinical outcomes by prolonging hospitalization and increasing mortality.

Three key stages of perioperative patient management are analyzed. In the preoperative period, the necessity of comprehensive risk stratification beyond standard clinical scoring systems is substantiated, including the Revised Cardiac Risk Index and the National Surgical Quality Improvement Program model. High prognostic value is demonstrated for biomarkers (such as N-terminal pro–B-type natriuretic peptide and high-sensitivity troponin), as well as for advanced instrumental diagnostics (echocardiography, stress testing, and cardiopulmonary exercise testing) aimed at assessing functional reserve. In the intraoperative period, the effectiveness of goal-directed hemodynamic optimization based on changing parameters (stroke volume variation and pulse pressure variation) is highlighted for the prevention of perioperative myocardial injury and hypoperfusion. In terms of respiratory protection, the focus has shifted from isolated reduction of tidal volume to comprehensive monitoring of lung mechanics, with driving pressure identified as a key determinant. The importance of individualized positive end-expiratory pressure settings and the use of recruitment maneuvers guided by objective monitoring methods is emphasized to prevent atelectasis and ventilator-associated lung injury. In the postoperative period, the efficacy of respiratory support strategies (including noninvasive ventilation and high-flow nasal oxygen therapy) is substantiated for the prevention of acute respiratory failure. Particular attention is paid to active complication surveillance using serial measurements of biomarkers (high-sensitivity troponin) for early diagnosis of myocardial injury.

The review concludes that integration of modern cardiorespiratory monitoring strategies into enhanced recovery after surgery protocols, including adequate analgesia and early mobilization, is a necessary condition for improving surgical outcomes.

The publication Human Aging and Longevity presents the most relevant issues in modern gerontology, ranging from theories and mechanisms of aging to the development of age-associated diseases, with translation of theoretical approaches in biogerontology into clinical practice.