Objective. To perform a morphological evaluation of the efficacy of radiofrequency pulmonary artery denervation using immunohistochemical staining of ganglionic nerve plexuses and autonomic nerve fibers with antibodies against S-100 protein.

Materials and Methods. Thirty pulmonary trunks from individuals who died of extracardiac pathology, aged 31 to 65 years (autopsy material), were studied. Five pulmonary trunks served as controls, while 25 were treated with radiofrequency pulmonary artery denervation (RFA-PA) using an experimental generator (440 kHz, power 10 W). Paraffin sections of 4 μm thickness were stained on a Leica Bond MAX immunostainer with polyclonal antibodies against S-100 protein. The relative area of nerve fibers (Srel.) was used as the statistical parameter.

Results. In control specimens, pulmonary nerve fibers after S-100 protein staining were predominantly detected along the left lateral edge of the pulmonary trunk: median Srel.=5.72% (95% CI 4.27–8.95). A small number of fine nerve fibers were found in the anterior and posterior walls of the pulmonary trunk:
Srel.=0.99% (95% CI 0.48–0.93), p<0.0001. In sections of pulmonary trunks subjected to RFA-PA, nerve fibers did not stain for S-100 protein, indicating thermal coagulation of proteins with loss of specific three-dimensional structure and antigenic properties.

Conclusion. Quantitative immunohistochemical evaluation using antibodies against S-100 protein is an objective method for verifying irreversible thermal damage to autonomic nerve fibers of the pulmonary artery and allows assessment of radiofrequency denervation efficacy. This method can be used in clinical and experimental work to evaluate ablation efficacy in both autopsy and biopsy material.

Background. Tissue myeloid cells occupy a unique position among immune response cells and form cooperative connections with the nervous, endocrine, and immune systems. The liver, being a central metabolic organ, is actively involved in adaptive processes during physical exercise; however, the role of mast cells in these processes remains insufficiently studied.

Aim. To evaluate the response of mast cells in different liver zones and the levels of IL-6 and TNF-α in blood plasma under conditions of simulated physical exercise of varying intensity.

Materials and Methods. Experiments were conducted on male rats (n=32, body weight 240 g) divided into
4 groups: control (n=8), light exercise (n=8), moderate exercise (n=8), and heavy exercise (n=8). Physical exercise was modeled by forced swimming in a water bath at 29–32°C for 15, 30, and until exhaustion
(55–59 minutes), respectively. A total of 10 exercise sessions were performed. Liver samples were fixed in 10% neutral formalin, paraffin sections were prepared and stained with hematoxylin and eosin, as well as toluidine blue to detect mast cells. The distribution density of mast cells, mast cell degranulation index (MCDI), and cell area were determined. TNF-α and IL-6 levels in blood plasma were measured by ELISA.

Results. Light exercise did not cause statistically significant changes in mast cell parameters or cytokine levels. Moderate exercise increased the number of mast cells by 1.6-fold, decreased the density of compact forms by 1.1-fold, and increased MCDI by 1.4-fold. Heavy exercise increased the number of mast cells by 2.8-fold, decreased the proportion of compact forms by 1.2-fold, increased MCDI by 1.9-fold, and increased cell area by 1.6-fold (p<0.05). In blood plasma after heavy exercise, TNF-α levels increased by 4.4-fold and IL-6 by 2.6-fold (p<0.001). Histologically, degenerative changes in hepatocytes and inflammatory cellular infiltrates were detected. Strong correlations were found between TNF-α, IL-6, and MCDI (r=0.9, p<0.05), and between TNF-α, IL-6, and mast cell levels (r=0.8, p<0.05).

Conclusion. Hepatic mast cells participate in the development of inflammatory responses during intense physical exercise, manifested by increased numbers, activation of degranulation, and correlation with elevated levels of proinflammatory cytokines in blood.

Objective: to demonstrate the existence of various morphological variants of neurovascular relationships in Background. The greater sciatic foramen is a region of practical interest to a wide range of specialists due to the numerous nerve trunks that pass through it, which may be subjected to compression in this area or be damaged during invasive medical procedures.

Aim. To analyze the sources of literature on the anatomy of the greater sciatic foramen and its related anatomical structures to identify underexplored issues.

Materials and Methods. A literature search was conducted in electronic databases (PubMed, Scopus, Web of Science, eLibrary) and monographs available in scientific medical libraries. Inclusion criteria: publications in Russian and English containing original data on the anatomy of the greater sciatic foramen, piriformis muscle, sciatic nerve, and pelvic bones. Search period – 1937–2024.

Results. The literature analysis showed that the most studied structure of the greater sciatic foramen is the piriformis muscle. Various classifications of this muscle have been proposed, taking into account the sites of its attachment to the sacrum, the length of its muscle bellies, and the position of the sciatic nerve relative to this muscle. The data presented demonstrate that the question of the influence of the morphology of this muscle on the development of piriformis syndrome remains a topic of discussion and is unresolved. At the same time, the bony structures forming the edges of the sciatic foramen are insufficiently studied. The greater sciatic notch of the pelvic bone shows pronounced sexual dimorphism in size and shape; however, its influence on the parameters of the foramen as a whole is not covered in the literature.

Conclusion. There is a need to determine the sizes and shapes of the greater sciatic foramen in relation to the sizes of the piriformis muscle, taking into account individual characteristics of the body (sex, age, anthropometric and ethnic parameters).

Background. Primary choriocarcinoma of the mediastinum is a rare aggressive malignant germ cell tumor with poor prognosis. The disease predominantly affects young men and is characterized by high metastatic activity.

Case Presentation. We present a case of primary metastatic choriocarcinoma of the mediastinum in a 26-year-old man. The disease manifested with acute onset of cough, dyspnea, fever, and pulmonary hemorrhage. Computed tomography revealed a mediastinal mass measuring 131×60 mm with multiple lung lesions. Serum human chorionic gonadotropin level was 1308.0 mIU/ml. Video-assisted thoracoscopy with atypical resection of the upper lobe of the left lung was performed. The patient died in the postoperative period. Autopsy revealed a mediastinal tumor measuring 7.0×6.0×5.5 cm, dark red in color, with soft-elastic consistency and multiple hemorrhages, with metastases to the lungs, liver, kidneys, spleen, brain, and lymph nodes. Histological examination revealed atypical syncytiotrophoblasts and cytotrophoblasts with high mitotic activity. Immunohistochemical study showed positive staining for PanCK, hCG, Inhibin, p63, Glypican3 and negative for CD30, confirming the diagnosis of choriocarcinoma. Total examination of the testes revealed no pathological changes.

Conclusion. Primary choriocarcinoma of the mediastinum requires early diagnosis based on comprehensive evaluation of clinical, laboratory, and instrumental data, but definitive verification is only possible through morphological examination with a broad panel of immunohistochemical markers. The prognosis remains extremely poor.

Objective: to evaluate morphological and molecular biological changes in the myocardium of male BALB/c mice on days 14, 28, 42, and 60 of experimental autoimmune myocarditis.

Materials and Methods. Experimental autoimmune myocarditis was induced in adult male BALB/c mice (n=60) by three subcutaneous immunizations with porcine myocardial homogenate in complete Freund's adjuvant. Animals were sacrificed on days 14, 28, 42, and 60. Morphological examination was performed using hematoxylin and eosin staining, Mallory's trichrome staining, immunohistochemical analysis (CD3, CD68), and real-time quantitative PCR to assess the expression of Hif1a, Nfkb, Il1b, Il6, Il10, and Tgfb genes.

Results. On day 14, signs of acute inflammation were detected: lymphohistiocytic infiltration with CD3+ T lymphocytes and increased expression of Hif1a, Nfkb, Il1b, and Tgfb. By day 28, a decrease in pro-inflammatory gene expression and formation of fibrosis foci were observed. On day 42, expression levels of Il6, Il10, Hif1a, and Tgfb increased; morphologically, signs of cardiomyocyte damage were identified. By day 60, high expression of Il6 and Il10 persisted in the presence of myocytolysis.

Conclusion. The identified dynamics of molecular biological changes indicate the formation of a chronic inflammatory process with a predominance of anti-inflammatory cytokines IL-6 and IL-10 at late stages of autoimmune myocarditis in male BALB/c mice, which may contribute to disease progression and development of dilated cardiomyopathy.

Background. The digestive system is one of the main systems ensuring vital activity of the organism. Assessment of structural and functional changes in the organs of this system is important for identifying compensatory-adaptive reactions during space flight. Mast cells play a key role in regulating local homeostasis and adaptive processes; however, their morphofunctional state under weightlessness remains insufficiently studied.

Aim. To study the morphofunctional features of mast cells in the digestive system organs of Mongolian gerbils after orbital flight.

Materials and Methods. The experiment was performed on male Mongolian gerbils Meriones unguiculatus as part of the Foton-M No. 3 spacecraft research project (flight September 14–26, 2007). Three groups of animals were formed: flight group, synchronous ground experiment group in flight equipment mockup, and vivarium control group. Additionally, a 12-day ground experiment with antiorthostatic suspension using the Ilyin-Novikov method in the Morey-Holton modification was conducted. Fragments of the fundal stomach were fixed in 10% neutral formalin, with some material fixed in formalin containing 0.5% cetylpyridinium chloride. Histochemical (toluidine blue staining, chloroacetate esterase activity determination) and immunohistochemical methods (detection of tryptase, chymase, c-Kit/CD117) were used. Mucosal and connective tissue mast cell subpopulations were studied separately.

Results. In control animals, the main mass of mast cells was localized in the gastric mucosa, predominantly in the lower third of the glands. The synchronous experiment showed increased frequency of mast cell detection in the upper third of the mucosa and enhanced degranulation processes. After space flight, a decrease in the total number of metachromatic and tryptase-positive mast cells in the mucosa was observed, but an increase in chloroacetate esterase-positive, chymase-positive, and CD117+ cells occurred. Chymase expression was enhanced, particularly pronounced in the mucosa. Secretory processes were activated with an increase in the proportion of mast cells in the state of exocytosis and granule lysis. During antiorthostatic suspension, an increase in mast cell numbers in all stomach layers, enhanced chymase expression, and activation of secretory mechanisms were noted.

Conclusion. Space flight factors and simulation of weightlessness effects cause significant changes in the mast cell population of Mongolian gerbil stomach, manifested by subpopulation redistribution, changes in protease profile with enhanced chymase expression, activation of secretory activity, and migration of CD117-positive progenitor cells. These changes reflect active participation of mast cells in adaptive processes of the digestive system to space flight conditions.

Background. Oocyte competence is a determinant of successful fertilization and embryo development. Poor oocyte quality may lead to fertilization failure or in vitro embryo developmental arrest. Artificial oocyte activation (AOA) using calcium ionophores has been proposed to overcome oocyte activation deficiency in patients with fertilization failure and unsatisfactory embryo quality. The effectiveness of this technology is of interest to fundamental medicine specialists and ART clinics.
Aim. To evaluate the effectiveness of calcium ionophore-mediated oocyte activation at the embryological stage of assisted reproductive technology (ART) programs in patients with previous unsuccessful infertility treatments.
Materials and Methods. A retrospective cohort comparative study was conducted at the Clinical Hospital "Mother and Child" (Samara) from January to December 2024. Study group (n=35): cycles with AOA using calcium ionophore (A23187, Sigma) after ICSI by medical indications (low fertilization rate in history). Control group (n=61): cycles with standard ICSI procedure without activation. Inclusion criteria: age 18–43 years, partner sperm use, complete data on culture up to day 5. Vitrolife media (Sweden) were used for cell preparation and ICSI. Cells were obtained by transvaginal follicular aspiration 36–37 hours after ovulation trigger. After ICSI, cells were in-cubated in medium with Ca²⁺ ionophore (10 mM concentration) for 8–10 minutes at 6% CO₂, 5% O₂, and +37°C. Embryo quality was assessed using a scoring system based on Gardner et al. (1999) criteria, modified with additional morphological parameters.
Results. Main parameters–fertilization rate, cleavage rate, and blastocyst formation rate–showed no significant differences between groups (p>0.05). A significant difference was observed only in mean embryo score at trans-fer (2.91±2.09 vs 3.98±1.41, p=0.008). Clinical pregnancy rate confirmed by ultrasound (36.0% vs 30.4%) and implantation rate (27.3% vs 23.8%) remained comparable (p>0.05). A clinically significant trend toward re-duced difference between positive hCG and clinical pregnancy rate (4% vs 10.7% in control) was revealed, sug-gesting higher embryo competence in the AOA group and reduced early reproductive loss.
Conclusion. Calcium ionophore artificial oocyte activation does not lead to statistically significant improvement in main embryological parameters but demonstrates a trend toward reducing the gap between biochemical and clinical pregnancy, which may indicate improved embryo quality in patients with adverse reproductive history. Data accumulation and multicenter randomized studies with increased sample size are required for more reliable conclusions.

Objective: To demonstrate the existence of various morphological variants of neurovascular relationships in the human enteric nervous system.

Materials and Methods. Autopsy fragments of the small and large intestines from newborns (n=9) and adults of first mature age (n=12) were studied using classical histological methods (hematoxylin and eosin staining, pararosaniline with toluidine blue, Azure II-eosin) and a modified universal method for impregnation of argyrophilic structures. The topography, morphology, and blood supply of ganglia of the myenteric and submucosal nerve plexuses were examined.

Results. A modular principle of blood supply to ganglia and interganglionic cords of the human enteric nervous system was established. In newborns, 79% of ganglia are located within the lumen of lymphatic microvessels, and neurocyte nutrition is provided by lymph (neurolymphatic variant). In 21% of ganglia, a neurolymphohematic variant with blood microvessels was identified. In adults of first mature age, an extraneural microvascular bed with a network-type module functions (neurohematic variant). Microvascular modules of interganglionic nerve tracts are organized according to a magistral type with intra- and extraneural microvessels. Arteriovenular anastomoses and countercurrent gas exchangers were detected.

Conclusion. At all stages of differentiation of enteric nervous system neurocytes in humans (neuroblast stage, growth stage, and maturation stage), corresponding morphological variants of neurovascular relationships function: interstitial, neurolymphatic, neurolymphohematic, and neurohematic, which ensures optimal conditions for differentiation and long-term stable survival of a heterogeneous population of neurocytes.