This article is dedicated to the memory of Professor Igor Eduardovich Esaulenko (18.03.1956 – 19.08.2025), Rector of the Voronezh State Medical University named after N.N. Burdenko (2000–2025), Doctor of Medical Sciences, and a prominent organizer of medical education and science. Based on archival materials and documentary evidence, the article analyzes the multifaceted activities of the scientist aimed at the development of the morphological school at the Voronezh State Medical University named after N.N. Burdenko. Key initiatives of I.E. Esaulenko are examined: the creation of university research infrastructure (Research Institute of Experimental Biology and Medicine), the modernization of the educational process at the Department of Normal Human Anatomy, and the support of scientific and historical-medical research dedicated to outstanding representatives of the Voronezh school of morphologists. A separate section of the article reveals I.E. Esaulenko's contribution to establishing a systematic dialogue between medical education and the Russian Orthodox Church. The professor's work is viewed as an integrated system that unites the academic understanding of the human being with the cultivation of the moral foundations of the medical profession. This article is intended for historians of medicine, medical university educators, researchers in the field of morphology, and anyone interested in the development of medical education and its spiritual and moral foundations.

The aim of the study was to study the ultrastructural characteristics of the thyroid gland (TG) in diffuse toxic goiter (DTG) in patients from a control group and in those with moderate and severe thyrotoxicosis.

Material and methods. Surgical specimens of the thyroid gland (TG) from 12 patients with diffuse toxic goiter (DTG) were examined. Control samples consisted of fragments of non-neoplastic tissue (n=12) taken from the resected thyroid lobe of patients with follicular neoplasms (Bethesda IV). The material was obtained by excising a tissue fragment of 2–3 mm³, which was then fixed in glutaraldehyde and osmium tetroxide. The ultrastructure of the thyroid epithelium within the follicles and in areas of proliferation, as well as the vascular bed, was studied using transmission electron microscopy. At the light-optical level, paraffin sections stained with hematoxylin and eosin, and semi-thin sections stained with toluidine blue, were examined.

Results. In DTG, changes were detected in the follicular epithelium and stroma of the thyroid gland. Heterogeneity of thyrocytes was noted: from columnar cells with smooth nuclear contours and minimal chromatin changes to thyrocytes with numerous protrusions of the nuclear membrane, chromatin hypercondensation, and dystrophic changes in the cytoplasm. The morphology of the granular endoplasmic reticulum varied from fragmentation and cisternal dilation to its destruction. In thyrocytes, degradation of mitochondrial cristae and clearing of the matrix were observed, especially in cells with hyperchromatic nuclei and signs of dystrophy. Thyrocytes were elongated in the basal-apical direction, characterized by lengthening of microvilli and the formation of long cytoplasmic processes of the apical membrane. Accumulations of phagosomes and colloid vesicles at the apical pole and throughout the cytoplasm reflect the high intensity of colloid uptake. The proliferating epithelium was represented by clusters of thyrocytes with signs of high synthetic activity. In the follicular epithelium, dissociation of tight junctions at the apical membranes was noted, leading to impaired follicle integrity. The basement membrane was thickened and folded. Vessels were grouped at the base of thyrocytes and between follicles, represented by fenestrated capillaries with stasis and sludging of erythrocytes. The endothelium was thinned, containing lysosomes, microvesicles, and secretory granules.

Conclusion. The morphological heterogeneity of the follicular epithelium in DTG is due to the different functional states of thyrocytes. The key changes affect the synthetic and energy-generating apparatus of the cells, which is caused by hyperfunction. Dystrophic changes in the cytoplasm of thyrocytes indicate an imbalance between the processes of colloid uptake and the hydrolysis of hormones dissolved within it. The enhancement of metabolic exchange between thyrocytes and capillaries, which mediates the toxic effect of hormones in DTG, is ensured by increased permeability of the basement membrane and endothelium, as well as the formation of new capillaries. The vascular component may represent a promising target for mitigating the toxic effects of thyroid hormones, alongside antithyroid therapy.

Autotransplantation of the thoracodorsal flap with complete preservation of its sensitivity is a pressing issue in reconstructive mammoplasty.

The aim was to study the structural features and spatial relationships of the lateral cutaneous branches (LCBs) of the intercostal nerves Th₅, Th₆, Th₇, Th₈, Th₉ and the thoracodorsal nerve (TDN) in women from the perspective of innervation of the thoracodorsal flap.

Material and methods. Anatomical dissection of the LCBs of the intercostal nerves Th₅, Th₆, Th₇, Th₈, Th₉ and the TDN along their entire course was carried out in 39 female cadavers (57–97 years of age). The coordinates of the nerve origin points were determined in relation to the clavicle and topographic landmarks. The diameter, length, direction, and angles of inclination in the anatomical planes were measured. Intrafascicular dissection was performed to identify the number of fascicles in the thoracodorsal nerve, along with their diameter, location, and functional type.

Results. In women, the LCBs of the intercostal nerves Th₅, Th₆, Th₇, Th₈, Th₉ measure 2.6 [1.5; 3.2] cm in length. They arise from the main nerve trunks between the midclavicular and anterior axillary lines, run laterally, and divide into anterior and posterior branches. The anterior branches are directed medially in an oblique downward course at an angle of 50° [42°; 55°], supplying the skin up to the parasternal line. The posterior branches turn posteriorly, follow an oblique upward course at an angle of 44° [36°; 49°] (p<0.001), and supply the skin up to the posterior axillary line. The combined length of the LCBs and their anterior branches is 7.7 [6.4; 8.5] cm; the combined length of the LCBs and their posterior branches is 7.5 [6.6; 8.6] cm (p=0.825); and the combined length of the anterior and posterior branches is 10.3 [10.0; 10.6] cm (p<0.001). The TDN is a mixed nerve. It arises from the posterior cord of the brachial plexus between the midclavicular and anterior axillary lines, located 3.0 [2.2; 3.5] cm below the clavicle and at a depth of 4.3 [3.8; 5.0] cm. In the frontal plane, the nerve deviates laterally from the vertical line at an angle of 40° [30°; 45°]; in the sagittal plane, it deviates posteriorly at an angle of 30° [20°; 35°]. The nerve consists of one motor fascicle with a diameter of 0.3 [0.30; 0.35] mm, located in the posterolateral portion, and one to three sensory fascicles with a diameter of 0.25 [0.25; 0.30] mm (p=0.005), which are situated anteromedially.

Conclusion. The differences in size, spatial distribution, and function between the LCBs of the intercostal nerves Th₅, Th₆, Th₇, Th₈, Th₉ and the thoracodorsal nerve provide the anatomical basis for preserving sensation when the split thoracodorsal flap is used in reconstructive breast surgery.

The aim of the study was to assess the morphological, ultrastructural, and immunohistochemical features of multinucleated giant trophoblast cells (MGTCs) within the myometrium of women (at 34– 38 weeks of gestation) presenting with abnormally invasive placenta.

Material and methods. The study included 31 pregnant women aged 27–43 years, of whom 19 women (at 34–38 weeks of gestation) had pathological placental attachment, with identified placenta accreta (n=7) and placenta increta (n=12) into the uterine wall. The comparison group consisted of women (n=12) without pathological placental attachment. Myometrial fragments were fixed in 10% formalin solution, embedded in paraffin, and stained with hematoxylin and eosin. Immunohistochemical examination was performed on paraffin sections of the placenta using primary antibodies to cytokeratin 8, CD₆₈, TF (tissue factor), CD₁₆₃, CD₂₀₆, CD₁₄, CD₁₆, IGFBP-1, placental lactogen (PL), and bhCG; ultrastructural features of MGTCs were also studied.

Results. The epithelial phenotype of MGTCs was confirmed by the detection of cytokeratin 8, weak expression of placental lactogen, b-hCG, tissue factor, and the absence of expression of both macrophage lineage markers (CD₆₈, CD₂₀₆, CD₁₄, CD₁₆, CD₁₆₃) and the decidual cell marker (IGFBP-1). In samples from the comparison group, MGTCs were sparse. The identified ultrastructural features MGTCs such as a significant number of granular endoplasmic reticulum cisternae, the presence of numerous mitochondria, and Golgi complex structures — indicate their high synthetic and secretory activity. At the same time, the presence of multiple microvilli on their surface suggests the capacity for further invasion, which may be particularly important in placenta increta.

Conclusion. Thus, the epithelial origin of MGTCs was confirmed, and their high synthetic activity, as well as their ability to invade and migrate into the uterine wall, was demonstrated.

The aim of the study was to study the morphometric parameters of growth plate cells in the proximal tibia in Blount's disease.

Material and methods. The study was conducted on cells isolated from the medial growth plates of the proximal tibia in Blount's disease grade III–IV. The material was obtained from 12 children (4 boys and 8 girls) (n=12) aged 3–9 years at the clinic of pediatric orthopedics of the Ya.L. Tsivyan Novosibirsk Research Institute of Traumatology and Orthopedics. The cells were cultured from passages 1 to 4, fixed, and stained for key chondrogenic (collagen type II and SOX₉) and neural (SOX₂, SOX₁₀, PAX₃, PAX₆, MSI₁, Nestin, HNK₁, TUBB₃, NF₂₀₀) markers. Morphometric analysis of immunopositive cells was performed using ImageJ software. The obtained data were processed using standard statistical methods with the application of the Shapiro–Wilk test and Student's t-test.

Results. Fluorescence staining of most growth plate cells revealed a positive reaction for the studied chondrogenic markers. Among these immunopositive cells, bipolar and multipolar cells with two or more processes expressing early (SOX₂, SOX₁₀, PAX₃, PAX₆, MSI₁, Nestin, HNK₁) and late (TUBB₃, NF₂₀₀) neural markers were identified. During cultivation, an increase in the proportion of positively stained cells for the majority of the studied neural markers was observed, along with an increase in fluorescence intensity, an increase in the number of processes, and an increase in the mean process length. Statistically significant differences in morphometric parameters (nuclear area, cytoplasmic area, and cell area) combined with differences in the nuclear-to-cytoplasmic ratio were found between cells expressing chondrogenic and neuronal markers.

Conclusion. The results indicate the presence of cells of neural origin in the growth plate of the proximal tibia in Blount's disease. Positive staining for the transcription factors PAX₃, PAX₆, SOX₂, SOX₁₀, as well as for the markers HNK₁, MSI₁, Nestin, and TUBB₃, supports the hypothesis regarding the role of neural crest cells in the development of this pathology.

The aim of the study was to investigate the cytoarchitectonic dynamics and cause-and-effect relationships between changes in layers III and V of the sensorimotor cortex of white rats during chronic cerebral ischemia.

Material and methods. Chronic cerebral ischemia was modeled in 72 male Wistar rats by bilateral ligation of the common carotid arteries. Animals were sacrificed at the control time and after 30, 90, 150, 210, and 270 days (n=6 in each group). Histological and morphometric examination of frontal sections of layers III and V was performed using Nissl staining. Statistical processing was performed using single-factor, correlation, regression, and lag analysis using both parametric and nonparametric criteria.

Results. Statistically significant specific differences in the dynamics of neurodegenerative changes were found in layers III and V. In layer III, a nonlinear, wave-like dynamics of the total numerical density of neurons and the numerical density of normochromic neurons was revealed with a pronounced decrease on the 30th day (40.6±1.9 versus 70.7±2.1 in the control and 14.2±0.6 versus 67.3±1.4 in the control; p<0.001), followed by partial recovery by the 150th day and repeated deterioration by the 270th day. In layer V, the changes were less pronounced and were predominantly linear. A strong positive correlation was found between of the total numerical density of neurons and the numerical density of normochromic neurons within each layer (layer III: r=0.78; layer V: r=0.85; p<0.001 for both). Regression and lag analyses confirmed the cascade nature of cytoarchitectonic reorganization: changes in layer III statistically significantly predicted subsequent changes in layer V (β=0.287, p=0.003 for the numerical density of normochromic neurons).

Conclusion. Chronic ischemia causes a cascade of neurodegeneration that initiates in the upper parvocellular layer III and involves the underlying layer V. The identified specific patterns of damage in layers III and V of the sensorimotor cortex are of key importance for better understanding the pathogenesis of ischemic brain lesions and can serve as a basis for the development of neuroprotective strategies.

The aim of the study was to assess the morphofunctional state of the supraoptic and paraventricular nuclei of the hypothalamus in rats following long-term intragastric administration of formalin and hydrogen peroxide, as well as additional oxytocin exposure.

Material and methods. A comparative assessment of the morphofunctional state of the magnocellular (supraoptic and paraventricular) hypothalamic nuclei was performed in two groups of rats (n=30, male Wistar rats, weighing 190–210 g). Over a period of 6 months, each group of animals received intragastric administration of a mixture of 0.4% formaldehyde solution and 0.4% hydrogen peroxide solution in a 1:1 ratio. The second group of animals additionally received an intramuscular injection of oxytocin at a dose of 0.5 μg. Paraffin sections, 4–5 μm thick, were stained with Mayer's hematoxylin and eosin, as well as with Gomori–Gabe stain. Nonparametric statistical methods using STATISTICA 6.0 software were employed for data analysis. Statistical processing included the calculation of quantitative data presented as median and interquartile range (25th and 75th percentiles) in the format Me [Q1; Q3].

Results. After 6 months of administration of the formalin and hydrogen peroxide mixture in the group of animals without additional oxytocin administration, a comparative assessment of the morphofunctional state of neurosecretory cells (NSCs) of the supraoptic and paraventricular hypothalamic nuclei was performed. It was found that under conditions of prolonged exposure to formaldehyde and hydrogen peroxide in experimental animals, blockade of neurosecretory release and depletion of secretory mechanisms of the magnocellular hypothalamic nuclei (particularly NSCs of the paraventricular nuclei) were observed. Against the background of oxytocin administration, adaptive processes were noted in the hypothalamic–pituitary neurosecretory system in response to exposure to the formalin and hydrogen peroxide mixture.

Conclusion. Oxytocin administration altered the morphofunctional state of the studied hypothalamic NSCs: the proportion of pyknomorphic cells decreased, and the vessels of the microvasculature and ependymocytes of the third ventricle showed no destructive changes.

The aim of the study was to develop a technique for examining the intracranial part of the tri- geminal nerve using sectional material, to study the variational anatomy of its roots, morphometric characteris- tics and topographic-anatomical relationships of the nerve trunk with blood vessels, and the possibility of in vivo visualization using magnetic resonance imaging.

Material and methods. The study of the anatomical and topographic relationships between the trigeminal nerve trunk and blood vessels was conducted on 30 non- embalmed human cadavers (13 males and 17 females) of the second period of adulthood and elderly age (60–70 years). For this purpose, an original technique for opening the cranial vault was proposed. This approach allows for unilateral removal of the tentorium cerebelli, opening of the cerebellopontine cistern, preservation of the integrity of anatomical structures, and provides the opportunity to study their relationships in detail. The study of variational anatomy was carried out on 72 specimens (31 male, 41 female) of the brain obtained from individu- als of the second period of adulthood and elderly age.

Results. Three variants of the exit of the roots forming the trigeminal nerve trunk were demonstrated: in 63% of cases, separate emergence of two roots (sensory and mo- tor) was observed; in 32%, formation of a single root; and in 5%, two motor roots. Morphometric characteristics of the intracranial part of the trigeminal nerve were obtained (length and width of the trigeminal nerve trunk, anteroposterior and lateromedial dimensions of the trigeminal ganglion, length and width of the main branches of the trigeminal nerve (ophthalmic, maxillary, and mandibular nerves) before their entry into the foramina of the skull base. The topographic-anatomical relationships of the trigeminal nerve with the superior cerebellar artery and the superior petrosal vein were described.

Conclusion. An original dissection technique was devel- oped, allowing the study of the intracranial part of the trigeminal nerve while preserving the integrity of all ana- tomical structures. The conducted study clarified possible predisposing factors for the development of neurovas- cular conflict involving the trigeminal nerve trunk with the superior cerebellar artery and the superior petrosal vein. Three variants of the emergence of the trigeminal nerve roots were identified, with separate emergence of the sensory and motor roots being predominant. Using MRI, the possibilities of in vivo visualization of the tri- geminal nerve trunk and ganglion, as well as the study of their morphometric and topographic-anatomical rela- tionships, were demonstrated.

Neurological complications of COVID-19, particularly as part of the post-COVID-19 syndrome, represent a major global public health concern. The pathophysiological underpinnings of these conditions remain incompletely understood. The aim of this review is to systematize and analyze the current data on the interconnected cellular and molecular mechanisms of excitotoxicity, neurodegeneration, and impaired neuroplasticity underlying the central nervous system (CNS) damage in SARS-CoV-2 infection. For this review, a systematic literature search was conducted in the PubMed, Scopus, and Web of Science databases, as well as using the Google Scholar search engine to broaden the scope and include Russian scientific publications. The search was performed using keywords in both English and Russian ("COVID-19", "neuroinflammation", "excitotoxicity", "нейродегенерация", "neuroplasticity", and their combinations), which initially yielded 762 publications. After removing duplicates and screening titles and abstracts, 215 articles were selected for in-depth analysis. During the full-text review, articles lacking data on fundamental mechanisms and brief communications were excluded. The final synthesis included 80 of the most relevant sources, comprising both international and Russian studies. The analysis revealed that virus-induced neuroinflammation is a pivotal element that triggers glutamate dysregulation and an excitotoxic cascade, leading to acute neuronal death. These processes, in turn, contribute to the development of long-term neurodegenerative changes. The cumulative effect of these factors was found to cause a profound disruption of synaptic and structural neuroplasticity, which constitutes the molecular basis for persistent cognitive and affective disorders. Understanding this pathological continuum is essential for developing effective neuroprotective strategies.

The enzyme systems of living organisms catalyse biochemical reactions and are an important component of the functioning of organs and systems. Alkaline phosphatase is localised on the plasma membranes of cells and catalyses the hydrolysis of the phosphoester bond. This enzyme is found in liver, bone, kidney, intestine, placenta and many other organs and tissues. Levels of alkaline phosphatase activity can be altered in various diseases. Despite the universality of the mechanism of action, the function of alkaline phosphatase is poorly understood. Characteristics of alkaline phosphatase isoenzymes, both tissue-specific and tissue-specific: intestinal, germinal, placental. The analysis of literature data on the study of tissue-specific alkaline phosphatase function in bone calcification, in the accumulation of triglycerides by adipose tissue cells, in embryonic development and in spermatogenesis is performed. This review presents an analysis of data on the localisation of alkaline phosphatase in mammalian testes. Alkaline phosphatase was detected in the peritubular cells of the seminiferous tubules and in spermatogonia. Weak reactivity to alkaline phosphatase was observed in Sertoli cells. The enzyme is species-specific: it has been detected in the testes of rats, mice, dogs, guinea pigs, and human testes. Hamsters, rabbits, and bats do not express alkaline phosphatase. The molecular structure of alkaline phosphatase and its properties in relation to standard inhibitors have been characterised. However, the effect of the enzyme on the differentiation of primary germ cells and on the maturation of spermatogenesis cells in mammalian testes has not been studied. Further studies are needed to determine the role of alkaline phosphatase in the physiology of cells and tissues of the reproductive system, including germ cell meiosis.

The aim of the study was to investigate the electron microscopic and microscopic features of spermatids at the late stages of spermiogenesis (acrosome phase and maturation phase) in mammals.

Material and methods. Material from seven mammalian species (domestic bull, ram, northern fur seal, sea otter, Eurasian beaver, mink, black-brown fox) was used. For electron microscopy, testis samples were fixed in 2.5% glutaraldehyde and 1% osmium fixative. Sections were prepared using BS-490 and LKB-4800 ultramicrotomes. The sections were stained with uranyl acetate and lead citrate and examined with a Tesla BS-500 electron microscope.

Results. During the acrosome phase, the nucleus elongates and assumes an elongated shape, while the cells change their orientation within the seminiferous tubule: they are positioned so that the acrosomic structure faces the basal membrane of the tubule. The acrosomal cap further develops into the acrosome. In the final maturation phase, mitochondria are arranged in a spiral pattern around the axoneme of the flagellar apparatus. In the caudal part of the elongated spermatid, the flagellar apparatus of the spermatozoon, which is the main component of the future sperm tail, is formed from the distal centriole.

Conclusion. At the late stages of spermiogenesis, chromatin condensation in the nucleus and acrosome formation are completed. By the end of spermiogenesis, the contact between late spermatids and Sertoli cells diminishes, and spermatozoa move into the lumen of the seminiferous tubule and subsequently into the epididymal duct.