Vol 21, No 6 (2023)

Introduction. Recurrent pregnancy loss (RPL) is an early spontaneous termination of pregnancy before 20 weeks, which is defined as two or more miscarriages. Most of the known causes associated with the pathophysiology of RPL include endocrine disorders, antiphospholipid syndrome, intrauterine infection, anatomical defects of the uterus, etc. However, in approximately 50% of cases, the cause of the pathogenesis of RPL remains unclear and may be associated with a violation of immune mechanisms, such as maternal tolerance to fetal alloantigens and controlled inflammation, which play a decisive role in successful pregnancy.

Purpose of the review. To summarize current knowledge about the molecular cellular immune mechanisms that ensure the induction and maintenance of maternal-fetal tolerance and highlight the association between impaired immunoregulation and the development of RPL.

Methods. The materials were the results of research on the topic over the past 23 years. Publications included in the Pubmed and eLibrary.ru databases were analyzed.

Results. This review provides information about the immune regulation of pregnancy, which is carried out through the interaction of molecular mediators and effector cells of the innate and adaptive immunity. Current evidence points to a key role of the immune system in the pathophysiology of RPL. Successful pregnancy requires a finely regulated and tightly controlled balance between immune activation and tolerance to fetal antigens.

Conclusion. The main events occur in the uteroplacental zone, where trophoblast cells and maternal lymphocytes come into close contact. The search for biomarkers for pregnancy complications is the focus of scientists.

Introduction. The developed domestic dipeptide retro-analog of cholecystokinin (CCK) tetrapeptide (N-(6-phenylhexanoyl)-glycyltryptophan amide, compound GB-115) with antagonistic properties towards CCK1 receptors has anxiolytic activity, previously shown in preclinical and clinical studies.

Purpose of the study. Evaluation of the anxiolytic effect of GB-115 in tablet dosage form with subchronic oral administration in comparison with phenazepam in laboratory primates.

Methods. The experiment was performed on four male rhesus monkeys (Macaca mulatta) aged 5.7–6.7 years. After a 30-day period of adaptation to the conditions of individual housing, an experiment was performed with GB-115 (0.001 g tablets) and then with phenazepam (0.0005 g tablets). Both drugs were given one at a time (7 days), and then 2 tablets (7 days). Behavior was assessed by observing the object with registration according to the “Yes-No” principle of ethogram elements in the background periods, during the administration of drugs and during their withdrawal. Using enzyme immunoassay, the content of stress response biomarkers: cortisol and dehydroepiandrosterone sulfate (DHEA-S) was determined in blood serum.

Results. GB-115 (0.001 g each) and phenazepam (0.001 g each) reduced the stay of animals in the upper part of the cage compared to the background period, which indicates a decrease in the stress response. GB-115 (0.002 g each) decreased the cortisol/DHEA-S ratio. Phenazepam dose-dependently reduced serum cortisol levels without affecting DHEA-S levels; with the administration of phenazepam (0.001 g), a decrease in the cortisol/DHEA-S ratio was also recorded.

Conclusion. A positive effect of GB-115, when administered subchronically, on the weakening of the emotional stress reaction and restoration of adaptive behavior in rhesus monkeys was revealed, comparable to the effect of phenazepam, which confirms the possibility of using blockade of CCK1 receptors as one of the approaches for the treatment of anxiety disorders.

Introduction. It is known that in the pathogenesis of caries and non-carious lesions of teeth, an important role is played by enamel resistance, which is determined by numerous factors, among which the structure and physical and mechanical properties of tooth tissues are considered to be among the most important. This report summarizes the literature data on the Poisson’s ratio of fluorapatite (FAp), a biomaterial and one of the mineral components of dental hard tissues. The literature search was carried out in electronic databases Scopus, Web of Science, PubMed, Medline, Elibrary, MatWeb for the period from January 1970 to March 2023 inclusive. Some of the data are supplemented by our own calculations based on formulas for crystalline hexagonal systems (systems). As is known, Poisson’s ratio determines the volumetric response of materials and biological tissues to mechanical load, but its anisotropic properties have not been studied in detail.

Material and methods. Calculations of the Poisson’s ratio of fluorapatite were carried out in the computer algebra system Mathcad 15.0, using the online analysis of elasticity tensors ELATE, and an integrated molecular modeling system was used - the graphic package VESTA (Visualization for Electronic and STructural Analisis).

Results and discussion. The Poisson’s ratio values of fluorapatite crystals varied: minimum values 0.057–0.283, maximum values 0.302–0.494, average values obtained by integration in all directions 0.24–0.308. The coefficient of elastic anisotropy of the fluorapatite crystal lattice, calculated based on the values of Poisson’s ratio, is 1.21–5.29. The results obtained were compared with those of hydroxyapatite (HAp) crystals, dentin, enamel and filling materials. The highest values of the parameters μ and μ_max are found in dentin (0.312 and 0.54), the lowest μ_min are also found in dentin (0.13).

Conclusions. Fluorapatite crystals are elastically anisotropic, and Poisson’s ratio μ_max/μ_min varies over a wide range. The Poisson’s ratio of fluorapatite showed similarity with the transverse strain coefficient of isomorphic hydroxyapatite crystals (0.207–0.374), dentin (0.13–0.54), enamel (0.16–0.47) and dental composite filling materials (0.24–0 ,35). The latter should help improve the quality of restorations using filling materials for replacing hard dental tissues. It has been established that the organic component of dentin increases its Poisson’s ratio as a biocomposite and the anisotropy of elastic properties.

Introduction. An increasing number of reports of long-term negative consequences of COVID-19, characterized by chronic inflammation, tissue hypoxia, oxidative stress, metabolic changes at the level of all body systems, determines the search for criteria for assessing long-term post-Covid syndrome. A high level of information content of saliva as samples for laboratory diagnosis of respiratory syndromes has been shown. The fact that SARS-CoV-2 is present in saliva in high concentrations suggests that saliva studies will provide rapid acquisition of useful information about the pathogenesis of post-Covid syndrome, allows us to identify the most vulnerable areas of metabolic processes and target them in combination with other rehabilitation measures.

Purpose of the study: to evaluate the state of antioxidant protection and indicators of resistance to hypoxia in patients in the post-Covid period 6 monthes after the manifestation of the infectious process caused by SARS-CoV-2, according to biochemical analysis of saliva.

Material and methods. 58 people participated in the study. 28 people

control group, who denied the fact of the disease; 30 people

a comparison group who suffered a new coronavirus infection of moderate severity, confirmed by PCR. The concentrations of pyruvic acid, lactic acid, reduced glutathione, the activity of glutathione reductase, glutathione peroxidase, myeloperoxidase, and ceruloplasmin were determined in saliva.

Results. In the saliva of patients in the post-Covid period, there is a pronounced increase in myeloperoxidase activity, which indicates a chronic inflammatory process. An increase in ceruloplasmin activity indicates a deficiency of iron and copper, which are necessary for oxidative phosphorylation and cellular respiration. A change in the ratio of lactate to pyruvate indicates the accumulation of NADH2, so to change the Redox status of the body, characteristic of hypoxic conditions. A decrease in the activity of enzymes of the glutathione system was noted, which reflects the inhibition of the processes of AOD and mitochondrial oxidation.

Conclusion. A set of indicators characterizing AOD, the ratio of aerobic and anaerobic processes, iron and copper transport, provides information about the peculiarities of the course of the post-Covid syndrome, which substantiates the correction paths associated with restoring glutathione levels, indicators of iron and copper metabolism and increasing resistance to hypoxic processes.

Material and methods. The subjects of the study were nonlinear mice that received intraperitoneal injections of LPS at a dose of 1 mg/kg or sterile 0.9% NaCl. Serial frontal sections of the brain were prepared using a cryostat. To identify mast cells, sections were stained with brilliant green and methylene blue.

Results. The findings suggest that intraperitoneal administration of LPS increases the number of resident mast cells in the mouse brain, especially in the perivascular areas between the hippocampus and thalamus. The increase in the number of cells appears to be the result of their division or directed migration under conditions of developing inflammation.

Conclusion. Administration of LPS leads to an increase in the number of mast cells in the brain of mice. Mast cells are likely to be an important source of immune mediators in LPS-induced neuroinflammation, as evidenced by their active degranulation process.