The Institute for Nuclear Problems of the Belarusian State University (INP BSU) has developed equipment  and optimized the technology for synthesizing boron-doped pyrocarbon, a material for application in heart valve endoprostheses.

The purpose of this work was to evaluate the general and biochemical blood tests, mass coefficients of animal organs  and the dynamics of reactions of rat tissues to implantation of pyrocarbon material in the subcutaneous tissues of the interscapular region.

 Animals were monitored for 90 days. According to the morphometric data, the boron-doped pyrocarbon, synthesized  in INP BSU, was found to be non-irritating to the tissue in comparison with the control sample during all periods of observation. There was no significant effect of implantation of pyrolytic carbon on the parameters of the blood general and biochemical  analysis in rats compared with healthy animals. The results of necropsy showed that the mass of organs and mass coefficients  of animals did not deviate from the physiological norm during different periods of pyrocarbon sample implantation.

Thus, the boron-doped pyrocarbon material synthesized in INP BSU can be used for manufacturing heart valve endoprostheses.

Peritonitis is a surgical and general pathological problem, the relevance of which does not decrease despite the achievements of modern clinical and experimental medicine. Peritonitis, being one of the most severe complications  of various diseases and injuries to the abdominal organs, triggers a complex cascade of pathogenetic reactions with disruption of vital processes. The mortality rate for peritonitis is 20‒30 %, and in its most severe forms it reaches 50–80 %. High mortality is caused by endotoxemia, multiple organ failure and sepsis. To date, sufficient data have been accumulated, indicating  the importance of liver arginase in the processes of detoxification and vital activity of the body in normal conditions  and in pathology. There were reasons to believe that its activity would be significant in the pathogenesis of peritonitis. However, the elucidation of significance of the liver arginase activity in detoxification processes and in the pathogenesis  of septic conditions and peritonitis in particular has been still little studied.

The purpose of the study was to determine the significance of the liver arginase activity in the processes of detoxification, the formation of thyroid status and dyslipidemia in rats with experimental peritonitis (CLP-model).

In experiments on rats, it was found that liver arginase and nitrogen monoxide are involved in changes in the content of total cholesterol in the liver and lipoproteins in the blood serum, the level of iodine-containing thyroid hormones in the blood plasma and body temperature during CLP-peritonitis. Developing CLP-peritonitis in the conditions of liver argina- se depression by N^ω-hydroxy-nor-L-arginine at a dose of 10 mg/kg is accompanied by a more pronounced inhibition  of the detoxification function of the liver, worsening changes in the content of total cholesterol in the liver and lipoproteins  in the blood serum, and the level of iodine-containing hormones in the blood plasma and contributes to the development  of secondary dislipoproteinemia.

The aim of the study is to establish the association of variants of a number of genes involved in the reninangiotensin system with the severity of SARS-CoV-2 infection.

The study included 206 hospitalized patients with COVID-19: Group 1 – 99 patients with severe COVID-19; Group 2 ‒ 107 with moderate and mild forms of the disease.

Polymorphic variants of the ACE rs4646994, ACE2 rs2074192 rs2285666 and rs413031713 and LZTFL1 rs10490770 genes were analyzed using quantitative PCR with TaqMan probes (Primetech, Belarus) on a CFX96 thermocycler (Bio-Rad, USA). AGT rs699 and AGTR1 rs5186 gene variants were determined using a Rotor-Gene Q thermocycler (QIAGEN, Germany),  in accordance to the protocols of the manufacturer (Litekh, Russia).

We revealed that the genetic markers of the severe COVID-19 infection in the Belarusian patients are the heterozygous T/C genotype of the LZTFL1 rs10490770 variant, as well as the A-A haplotype of the ACE2 rs2074192 and rs2285666 loci, and the A-A-C allelic combination of the ACE2 rs2074192, rs2285666 and AGT rs699 genes. Genetic markers associated with mild/moderate severity of COVID-19 were also identified: heterozygous A/C genotype of the AGTR1 rs5186 variant,  G-G-T allelic combination at the ACE2 rs2074192 and rs2285666, AGT rs699 loci (among carriers of these gene variants,  the risk of severe disease is reduced).

The loci of the genes encoding the renin-angiotensin system – ACE2 rs2074192 and rs2285666, AGTR1 rs5186,  and the LZTFL1 rs10490770 genes, as well as allelic combinations between the ACE2 rs2074192, rs2285666 and AGT rs699 loci are informative markers for predicting the severity of COVID-19.

The influence of thyroid hormone (TSH) on the probability of pregnancy is a controversial issue in modern scientific literature, since impressive scientific data has been published lately questioning previously undoubtful fact that preconception levels of TSH must be decreased to target values not exceeding 2.5 mIU/l.

The aim of the research was to investigate the influence of elevation of TSH in the range of 2.5–4.0 mIU/l in women  on the outcomes of in-vitro fertilization (IVF) procedures by analyzing the parameters of controlled ovarian stimulation (COS) and embryological indicators of its efficacy, as well as the percentage of pregnancy and reproductive losses.

The work was based in “Centre for Reproductive Medicine”. The study included 195 married couples that under- went IVF due to infertility. Two groups were formed: Group 1 consisted of 94 women with pre-IVF TSH ranging between 2.5–4.2 mIU/l, while Group 2 included 101 women with the initial level of TSH before the beginning of ovarian stimulation less than 2.5 mIU/l.

It was established that in women with TSH ranging between 2.5–4.2 mIU/l with normal levels of free thyroxine, embryological parameters of COS efficiency showed comparable results of follicle growth, oocyte maturation, percentage  of blastocyst formation in both groups. The efficiency of in vitro fertilization was found to be independent of the preconception TSH level if this index was in the range of 2.5–4.2 mIU/l: comparable incidence of pregnancy (60.64 and 51.49 %; p = 0.254), incidence of spontaneous abortion in the 1st trimester (15.79 and 9.62 %; p = 0.500), incidence of late spontaneous miscarriage at gestational age 12–22 weeks (3.51 and 11.54 %; p = 0.709 were observed).

Electrophysiological research methods, in particular late nerve conduction responses, play an important role  n the diagnosis of a number of neurogenic disorders and, in particular in lumbosacral radiculopathy. Late responses include the F-wave, H-reflex, and A-wave.

The purpose of this study was to determine the diagnostic value of late responses to tibial nerve stimulation in patients with isolated S1 radiculopathy in comparison with clinical findings. We examined 32 patients with isolated S1 radiculopathy (16 women, 16 men), their average age was 43.5 ± 9.3 years.

An electroneuromyographic study of the tibial nerve on the injured side revealed the presence of an A-wave in 20 patients (62.5 %, p < 0.001). It was significantly more often combined with tests for spinal root irritation, and its localization before the F-wave was a characteristic feature of this pathology. The analysis of the F-wave parameters showed an increase  in its duration (p = 0.001) compared to the uninjured side, and compared to the control group there was a prolongation of both duration and latency (p < 0.001). Patients with the presence of an A-wave had more pronounced changes in the duration  and latency of the F-wave on the injured and uninjured sides. When analyzing the H-reflex, it was found to be absent  in 14 (43.8 %) and decreased in amplitude in 9 (28.1 %) patients on the injured side. The absence of the H-reflex was significantly more often detected in patients with the absence of the Achilles reflex (p < 0.05). The number of patients with the presence of an A-wave did not differ from that of patients with an increased duration of the F-wave or a decrease in the amplitude of the H-reflex (p > 0.05).

Despite the progress achieved in dental implantation, the problems of reducing the number of complications after implants placement and increasing their service life remain relevant. It is known that inflammatory complications that arise after intraosseous dental implantation serve as a serious aggravating factor affecting the stability and safety of the implant, which creates unfavorable conditions for further prosthodontics.

The aim of the study is to conduct a comparative analysis of the different-method effectiveness of dental alveoli preparation based on molecular-genetic microbiological research.

Research methods: clinical, molecular genetic, microbiological.

A comparative analysis of the different-method effectiveness of dental alveoli preparation based on the results  of a molecular genetic microbiological study is presented in the research. A mandatory stage of sanitation of the operating area is found by the presented research results. The mechanical method using a spherical bur and a physiodispenser,  the piezosurgical method using a spherical nozzle with a diamond coating can be a method of choice for dental alveoli preparation.

The gut microbiota plays an important role in the formation of the body’s regulatory systems (nervous, endocrine, immune), which is especially important at an early age. Hence, gut dysbiosis can lead to an impaired development of both the intestinal microbiota and these regulatory systems. Prebiotics can have a positive effect on the development of the intestinal microbiome, which can correct negative changes.

The aim of this study is to investigate the features of development of antibiotic-associated dysbiosis in the early postnatal period in rats and to evaluate the effect of 2′-fucosyllactose in health and during dysbiosis.

The study was conducted on Wistar rats aged 12–26 days. To develop dysbiosis at an early age, the following mixtures were used: a mixture of ampicillin trihydrate 75 mg/kg and metronidazole 50 mg/kg and a mixture of amoxicillin 30 mg/kg and cephalexin 20 mg/kg for three days, starting on the 12th day of life. As a prebiotic 2′-fucosyllactose at a dose of 1 g/kg was used, starting on the 12th day and to the last experiment day.

In healthy animals, there is a decrease in the gut content of Bifidobacterium spp. and Enterococcus spp. at the age  of 26 days. A mixture of ampicillin trihydrate 75 mg/kg and metronidazole 50 mg/kg leads to gut dysbiosis – growth suppression of bifidobacteria, lactobacilli and enterococci. After the end of antibiotics application and continued lactation,  the titer of the described bacteria is restored. 2′-fucosyllactose has an effect on the preservation of the titer of Bifidobacterium spp. and Enterococcus spp., both in healthy animals and after early dysbiosis.

Our results indicate that antibiotic-associated dysbiosis at an early age is characterized by a temporary but powerful effect. At the same time, the use of 2′-fucosyllactose leads to preserving important probiotic groups of intestinal bacteria, both in health and after dysbiosis.

The antihypoxic effect of a combination of bemethyl and thymoquinone after single intraperitoneal injection was studied in a model of hypercapnic hypoxia in a hermetic volume in mice. Thymoquinone had a dose-dependent protective effect by increasing the resistance of animals to hypoxia. At a dose of 10 mg/kg, it increased the life expectancy by 75.9 % compared with the control group, and at a dose of 30 mg/kg – by 90.2 %. The average effective dose of thymoquinone calculated by the regression analysis in this model was 14.1 mg/kg and the average effective dose of bemethyl was 148 mg/kg.  As part of a combination of bemethyl and thymoquinone in the ratio of 5 : 1, the activity of the compounds increases significantly, ED50 of bemethyl decreases to 39.0 mg/kg, the same indicator for thymoquinone becomes 7.8 mg/kg. Administration of a combination of 100 mg/kg of bemethyl and 20 mg/kg of thymoquinone to mice leads to increasing their lifespan under the standard hypoxic conditions up to 41.2 ± 5.7 minutes, which is 120.5 % more than in animals receiving placebo. The analysis of pharmacodynamics of a combination of drugs according to T. Chou showed an additive type  of interaction typical for compounds with different mechanisms of primary action. It was established that a combination  of bemethyl and thymoquinone in the weight ratio of 5 : 1 demonstrate synergism, which makes it possible to reduce 1.8–4.0 times the doses of components in their combined use.