Morphology

BACKGROUND: Circadian rhythms of body functions and processes are normally strictly coordinated with each other and environmental factors, which ensures optimal maintenance of the functioning of body organs and systems. However, no studies have assessed the circadian rhythms of hepatocyte organelles under experimental conditions.

AIM: To assess the daily dynamics of the cross-sectional area of rat hepatocyte mitochondria under conditions of dark deprivation, chronic alcohol intoxication, and their combination.

MATERIALS AND METHODS: The study analyzed 80 male and 80 female Wistar rats, divided into 4 groups of each sex: group 1 was kept under a fixed light regimen, group 2 under dark deprivation, group 3 in the same conditions as the control group but were subjected to chronic alcohol intoxication, and group 4 under dark deprivation and chronic alcohol intoxication. Liver samples, after fixation and wiring, were analyzed under a transmission electron microscope. Micromorphometric methods were used to assess the mitochondrial apparatus of hepatocytes.

RESULTS: In rat hepatocytes from the experimental groups of both sexes, the circadian rhythm of the cross-sectional area of the mitochondria with similar parameters was detected. Dark deprivation and chronic alcohol intoxication, acting both separately and together, resulted in the restructuring of mitochondrial size distribution, which was more pronounced in males.

CONCLUSION: The study indicates that the circadian rhythm of mitochondrial size is dependent on the lighting regimen and toxic effects of ethanol and its metabolites. The size ranges of the mitochondria in the hepatocytes of females, compared with those of males, are more resistant to the effects of dark deprivation and alcohol intoxication.

BACKGROUND: No studies have sufficiently evaluated the innervation of the mediastinal organs in the P1 period when the blood circulation switches from placental to pulmonary and the regulation of respiration and functioning of the cardiovascular system begin.

AIM: This study aimed to conduct a comparative immunohistochemical analysis of the innervation of the mediastinal organs of newborn rats.

MATERIALS AND METHODS: Immunohistochemical methods were employed for identifying neuronal markers: PGP 9.5 protein, tyrosine hydroxylase, and synaptophysin. Primary antibodies were applied to mediastinal sections after they had been deparaffinized.

RESULTS: Analysis of frontal sections of the cardiopulmonary complex of rats at P1 showed that the bronchi, esophagus, great vessels (aorta and pulmonary artery trunks), veins (pulmonary and caval), adipose tissue, lymph nodes, lung fragments, and heart occupied the upper and middle sections of the mediastinum. Closely adjacent parasympathetic and sympathetic ganglia, microganglia, nerve trunks, and plexuses of nerve fibers were identified using neuronal markers in the interstitium between organs. In the upper and middle mediastinum of newborn rats, synaptic structures were identified in the ganglia and paraganglia, mixed lobules of adipose tissue, esophageal and bronchial wall, around small arteries and arterioles for the first time using immunohistochemical methods.

CONCLUSION: This comparative study revealed that in the early period of postnatal development of rats, the walls of the esophagus, trachea, and main bronchi are most innervated in the mediastinum; in the myocardium and lungs, these nervous apparatuses are typically rare or absent. A high concentration of synaptic structures in the conducting myocardium has been described.

BACKGROUND: Radiotherapy for malignant neoplasms of the pelvic organs can lead to radiation-induced damage to healthy ovarian tissue, premature ovarian failure, and infertility. Research on reactive changes in the ovaries in response to electron irradiation and testing of radioprotective agents, such as platelet-rich plasma, remains relevant.

AIM: This study aimed to assess the inflammatory response in the ovary after platelet-rich plasma administration in a radiation-induced ovarian failure model.

MATERIALS AND METHODS: Fragments of the ovaries of four groups (I, control (n=10); II, fractional irradiation with electrons in a total dose of 20 Gy (n=10); III, fractional irradiation with electrons in a total dose of 20 Gy + platelet-rich plasma (n=10), and IV, platelet-rich plasma (n=10)) were studied histologically and immunohistochemically using antibodies to pro- (interleukin [IL]-1 and IL-6) and anti-inflammatory (IL-4, IL-10) cytokines, as well as CD3 and CD20.

RESULTS: The immunohistochemical study revealed that electron irradiation led to an increase in the expression of both pro- and anti-inflammatory cytokines and the number of CD3⁺ and CD20⁺ immunocompetent cells in the interstitial tissue of the ovaries, fractionally irradiated with electrons at a total dose of 20 Gy. The T-cell component was predominant over the B-cell component. Moreover, pre-irradiation administration of platelet-rich plasma contributed to a smaller change in the degree of morphological changes, expression of pro- (IL-1 and IL-6) and anti-inflammatory (IL-4 and IL-10) cytokines, and proportion of CD3⁺ and CD20⁺ immunocompetent cells in the interstitial tissue of the ovaries. In addition, the T-cell component of immunity was predominant.

CONCLUSION: Components of platelet-rich plasma, having anti-inflammatory and radioprotective properties, reduce the severity of inflammatory response (based on expression levels of pro- and anti-inflammatory cytokines) and number of T and Bimmunocompetent cells, which slow down the development of radiation-induced ovarian failure when exposed to fractional local irradiation with electrons in a total dose of 20 Gy.

The article analyzed data from relevant literature that focused on anatomical variations of the internal iliac vein (IIV), its structure, and morphometric characteristics.

P.A. LePage et al. (1991), D. Venieratos et al. (2012), and P. Kanjanasilp et al. (2019) have previously evaluated anatomical variations of the IIV using postvital materials. M. Shin et al. (2015) extensively analyzed the architectonics of the main trunk of the IIV according to vestibular methods (n=2488) and identified eight variants. This approach formed the basis of a similar work (n=1071) by A. Hekimoglu and O. Ergun (2021). D. Sat-Muñoz et al. (2020) and M.G. Shkvarko et al. (2021) also conducted a morphometric study of IIVs. D. Sat-Muñoz et al. categorized variants of IIV formation into three types, according to the classification of R. Gregoire (2007), based on the relationship of the IIV with its artery. According to D. Kachlik et al. (2010), in approximately 50% of cases, the root of the IIV is the internal genital vein, which penetrates the pelvis through the subclavian orifice; in 30%, the anterior and posterior trunks can be identified in the architectonics of the IIV by analogy with the internal iliac artery, which are the roots; in 20%, the IIV trunk is formed by many small tributaries, and roots and trunks could not be identified.

Our data revealed that the typical IIV variant is the one in which its roots and tributaries (except for the umbilical vein) correspond to the branches of the artery of the same name, and a typical variant of IIV architectonics should be considered the fusion of the anterior and posterior trunks, with the internal genital vein and superior gluteal vein as the roots, respectively. All visceral tributaries flow into the anterior trunk, and nearly all extramural tributaries accompanying branches of the internal iliac artery flow into the posterior trunk.

The majority of authors studied the architectonics of the main trunk of the IIV without the systematization of its tributaries. Based on the review of available literature, no modern clinically oriented classification of the variability of IIV architectonics has been established, satisfying the needs of modern surgery during interventions on the pelvic organs. Knowledge of the IIV anatomical variants and its tributaries is necessary when performing surgical interventions in the small pelvis, particularly during evisceration, to prevent blood loss.

This article outlined promising directions in the study of the IIV and its tributaries, namely, methods of three-dimensional modeling, including the use of augmented reality technology, at various stages of surgical treatment of locally advanced pelvic tumors.

The study analyzed the morphofunctional organization of the mammalian baculum (os penis). In many mammals, bone tissue caused the penis to harden, which forms the bone of the penis (os penis or baculum). This structure appeared later in evolution than others, and it is present only in representatives of the most evolutionarily young class of vertebrates, i.e., mammals. The baculum is present in the penis of marsupials and placental mammals (rodents, some bats, pinnipeds, cetaceans, individual predators, semi-monkeys, and some monkeys).

The bone tissue is usually located in the anterior region of the penis between the cavernous and spongy bodies. The baculum is an unpaired bone. On the cross-section of representatives of different species, the baculum can be rounded, square, triangular, or flat. Most often, the baculum is a cylindrical rod, expanded in the proximal and distal parts, and it has outgrowths of various shapes. Histogenesis of the bone tissue during os penis formation in embryogenesis occurs by indirect osteogenesis. In the area of the future os penis, a cartilaginous model is formed from the mesenchyme, in place of which the bone tissue then develops. The base of the baculum is formed by lamellar bone tissue, in which osteones are well expressed. Coarse fibrous (reticulofibrous) bone tissue and fibrous cartilage tissue are found on the surface of the baculum. The baculum was found to increase the overall hardness of the penis when bending during copulation.

Protein p53 is one of the most popular topics among researchers. Over the past 40 years since its discovery, more than 100 thousand scientific works have been written, and this is growing steadily. The increased interest in this protein among doctors lies in its participation in the development of malignant tumors, a socially significant group of diseases of the 21^st century. p53 is a tumor suppressor. Normally, when exposed to damaging factors, this protein promotes DNA repair or apoptosis, depending on the damage, which in turn prevents the accumulation of cells with mutant DNAs. When p53 mutates, it loses its function, leading to abnormal cell proliferation and tumor progression.

The role of p53 is not limited to carcinogenesis. It also participates in the regulation of the central nervous system; however, its role is ambiguous. Although p53 is also involved in the embryogenesis of nervous tissue and promotes the differentiation of neural stem cells, it can also have a damaging effect on neurons.

The literature review presents current data on the structure and function of p53, the main regulator of the human genome, and its homologs (p63 and p73). These proteins are considered to play a role in programmed cell death and carcinogenesis. The role of p53 family proteins in the functioning of the central nervous system and neuroprotection was also examined.

The issue of teaching brachial plexus anatomy to English-speaking foreign students remains confusing and uncoordinated these days because of significant differences in the presentation of materials in translated educational literature by Russian-speaking authors and in atlases, textbooks, and manuals used in other countries. This study aimed to analyze mind-mapping learning techniques and identify the advantages of their use when teaching “Brachial plexus anatomy” to foreign medical students. The materials included mind maps, textbooks, atlases, manuals, workshops, and workbooks on human anatomy for students of medical universities in Russian and English that describe the anatomy of the brachial plexus and personal experience of using mind maps. A mind map in human anatomy classes was provided in accordance with modern anatomical terminologies, discrepancies in the description of the anatomy of the brachial plexus in Russian and English were analyzed, and the advantages of their use in teaching foreign medical students were identified.

Professional development has come a long way that in 2023 we congratulated Natalia Rafailovna Karelina, Doctor of Medical Sciences, Professor, Member of the Board of the Scientific Medical Society of Anatomists, Histologists and Embryologists of Russia for her 80^th birth anniversary. For more than 21 years, she has served as the head of the Department of Human Anatomy at St. Petersburg State Pediatric Medical University and inspires the younger generation to scientific achievements. The staff of the Department of Human Anatomy of St. Petersburg State Medical University, friends and colleagues, and numerous students cordially congratulate Natalia Rafailovna and wish her a long life, good health, professional longevity, and continued enthusiasm for the benefit of her beloved medical science and pedagogy.