The emergence of novel SARS-CoV-2 genetic variants with increased transmissivity and reduced antibody neutralization efficiency is a threat to global public health. Reverse transcription polymerase chain reaction (RT-PCR) with the use of fluorescent probes, which make it possible to detect the single nucleotide substitutions, is a technique suitable for screening the SARS-CoV-2 RNA-containing samples for the already known functionally significant mutations in the S-gene, identification of which allows to define and differentiate the most epidemiologically significant genetic variants. The study was aimed to develop an assay for the large-scale monitoring of the spread of the SARS-CoV-2 top-priority variants. Based on the whole-genome alignment of the SARS-CoV-2 sequences, deposited in the GISAID database, primers and LNA-modified probes were selected to detect mutations in the S gene, typical for the Alpha, Beta/Gamma and Delta variants of concern (VOC). The developed reagent kit for detection of the key mutations in the SARS-CoV-2 S gene by the real time RT-PCR has good analytical and diagnostic characteristics and was authorized as a medical device (reagent) for in vitro use. The results of detecting the VOC and the key mutations with the use of the developed reagent kit were consistent with the data of the whole genome sequencing of 1,500 SARS-CoV-2 RNA samples. The developed reagent kit and the subsequent SARS-CoV-2 RNA sequencing assay used to perform the epidemiological monitoring of SARS-CoV-2 variants made it possible to promptly report the emergence of the Delta genetic variant in Russia, and to trace the dynamic changes in the prevalence of Delta in Moscow Region in April–September 2021. 

The clinical spectrum of SARS-CoV-2 infection continues to expand, raising  important fundamental issues regarding the SARS-CoV-2 cellular tropism and pathogenic mechanisms. Liver damage is observed in patients with all forms of  COVID-19, especially severe and critical forms, which could be due to the direct viral damage, immune dysregulation (systemic inflammatory response and cytokine storm), hypoxia-ischemia, drug-induced hepatotoxicity, and concomitant chronic disorders. Liver damage, defined primarily by elevated transaminase levels, is often observed in patients with COVID-19 and correlates with clinical outcomes, including mortality. Diagnostic criteria, pathogenesis, clinical characteristics, treatment, and prognosis of liver injury in COVID-19 should be clarified in further clinical trials. Currently, there is a critical shortage of proven treatment options for patients with COVID-19, resulting in an urgent need to study the multiple organ failure and liver damage pathogenesis in patients with this disease. The review provides information about the pathophysiological mechanisms of the SARS-CoV-2-induced liver damage and the development of liver failure in COVID-19. Information sources were searched in the PubMed database using the keywords “liver damage in COVID-19” and “immune liver damage in COVID-19”.

Development of drug delivery systems based on branched biocompatible polymers is one of the most promising areas of modern nanopharmaceutics. Researchers have been exploring this area several decades now, and the results of their efforts quickly find their way into production. Dendrimers, a new class of universal synthetic polymers with a highly functional surface, have a number of unique properties: constant size, high degree of branching, multivalence, solubility in water, definite molecular weight, internal cavities. With the release of VivaSol gel, the first dendrimer-based commercialized product, the "model range" of dendrimer carriers has grown significantly. Poly(amide-amine) (PAMAM) dendrimers, which consist of an alkyldiamine core and tertiary amine branches, are believed to be among the most promising compounds that can be used in the development of the new generation drugs. However, they were kept out of the list of clinically acceptable compounds for a long time because of their toxicity, unclear behavior in living systems and pharmacokinetic profile, as well the difficulties associated with establishing a therapeutic dose. This review presents basic information about PAMAM dendrimers and attempts to assess the prospects of their application in treatment of various diseases, including COVID-19.

In the beginning of 2020 there appeared an urgent need for substantial advancement of the medical and psychological support for medical personnel involved in medical care provided to patients with the new coronavirus infection (COVID-19) in hospital settings. This need originated from the necessity to diagnose the risks of doctors developing mental states that adversely affect their professional performance and, subsequently, lead to disorders. In addition, there are under-researched matters of dependence of the prevalence of destructive mental states on the intensity of workload experienced by doctors in the "red zones", where the risk of patient fatalities is high. This study aimed to investigate the workload-dependent dynamics of psycho-emotional exhaustion among the medical staff of a COVID hospital. We analyzed the psychological tests (MBI, Maslach Burnout Inventory) that 121 people completed during a four-week assignment in the "infectious" zone and two weeks in the observation department. Seventy-nine doctors comprised the heavy workload group and 42 were in the moderate workload group. The study showed that healthcare workers experiencing heavier workloads exhibit high values of the psycho-emotional exhaustion indicators more often. We registered significant differences (р ≤ 0.05) by the Emotional Exhaustion scale at the third and fifth weeks of the study. By the fifth week, i.e., when the assignment in the "infectious zone" was over, heavy workload group had the median of 25 (23.5; 27), while in the moderate workload group it was 14 (14; 15), which is 56% lower.

Micropolarization was already proved an effective method for restoring impaired brain functions and improving intracerebral processes in the absence of impairments. Combining stimulation methods is a promising approach: a combination of electrode positioning methods can increase the efficacy of the procedures and find application in various fields, from sports through machinery operation to support of operatives of the Ministry of Emergency Situations, etc. This study aimed to assess the effect of a single combined micropolarization procedure on the functional state of the autonomic nervous system and sensorimotor reactions of conventionally healthy individuals. It involved 31 people and relied on the methods enabling evaluation of sensorimotor reactions, cardiorhythmography with spectral analysis of heart rate variability and pupillary reflexes assessment. Volunteers underwent the combined micropolarization procedure once, the duration of the procedure was 40 minutes. The most effective combinations were transspinal plus transcranial micropolarization with positioning in the region of premotor cortex (short-term shift of the autonomic balance towards parasympathetic influence by 48.7%; optimization of the pupil recovery function by 26.4%; increase in interference immunity by 32.2%) and "solar" plus transcranial micropolarization in the area of the temporal zone of cerebral cortex (15.8% increase of the orthostatic test transition period ratio; 6.2% deceleration of the visual-motor reaction).

Chlorhexidine bigluconate (CНX) is widely used as a disinfectant, but it is not effective against spore-forming microorganisms, as well as viruses. In this work, a method has been found to increase the biocidal activity of chlorhexidine by using it as part of a complex including ethylenediaminetetraacetic acid (EDTA) and zinc chloride. The structure of the three-component complex СНX-EDTA-zinc is proved by the MALDI-MS method. The biocidal activity of the chlorhexidine complex has been studied in vitro and in vivo experiments. It is shown that the complex is significantly superior to chlorhexidine alone, both in terms of activity level and in the breadth of biocidal action. In relation to the studied bacterial and fungal strains, the СНX-EDTA-Zn complex was 4–5 times more active than chlorhexidine bigluconate. In concentrations from 1.0 mg/ml to 0.008 mg/ml (depending on the type of micro-organism), in vitro the complex showed both bacteriostatic and bactericidal effects against the main pathogens of bacterial diseases of birds. In clinical conditions, the complex has shown high efficiency in the treatment of dermatitis in small domestic and farm animals. Also, in vitro and in vivo, the complex showed unexpectedly high antitubercular activity comparable to that of monofloxacin, including on drug-resistant strains of mycobacteria. in vitro experiments involving polio virus and adenovirus have shown that the СHX-EDTA-Zn complex possesses virulent action.

Cyclophosphamide is used for the treatment of lymphoma, leukaemia, some solid tumours, and autoimmune disorders. When carrying out myeloablative cytostatic therapy, the doses of cyclophosphamide are prescribed, which cause irreversible pancytopenia. Early toxic effects of such doses are manifested by asthenic and emetic syndromes, limiting the treatment tolerance. Administration of cyclophosphamide in a dose of ≥ 600 mg/kg is accompanied by hyperammonaemia and symptoms, specific to the acute ammonium salt intoxication. Endotoxemia, resulting from the increase in the intestinal barrier permeability due to the impaired gastrointestinal motility, is considered the possible mechanism underlying these phenomena. The study was aimed to test this hypothesis. Radiographic assessment of the rat gastrointestinal peristalsis was performed within 25 h after administration of cyclophosphamide in a dose of 1000 mg/kg, which was equivalent to myeloablative dose for humans. Intraperitoneal, subcutaneous or intragastric administration of cyclophosphamide slowed down the gastrointestinal transit of bariumsulfate. In the case of subcutaneous cyclophosphamide injection, a moderate effect was observed. In the case of cyclophosphamide administered by gavage, the effect was manifested by a complete halt of transit. Thus,  modelling myeloablative cytostatic therapy with cyclophosphamide in rats is associated with gastrointestinal stasis. The changes reported may promote the entry of the gut microbial products into the bloodstream and ensuing endotoxemia.

In extreme situations, reliable detection of the minimum therapeutic concentrations of psychotropic substances is important, since this allows one to provide adequate resuscitation. The group of benzodiazepine derivatives, which includes bromodihydrochlorophenylbenzodiazepine (phenazepam), is widely used in clinical practice. Along with the positive clinical effect, phenazepam has numerous side effects, capable of causing poisoning, even death. The study was aimed to develop the method for detection of the phenazepam metabolites by high-resolution HPLC–TMS suitable for achieving the aims and objectives of forensic medical expertise in case of the ultra-low urine substance concentrations. Urine of six patients (males and females aged 28–40), who were prescribed phenazepam and took the drug at minimum therapeutic concentrations on an ad hoc basis, was used during the study. Optimum conditions for the analyte chromatography after the urine sample preparation were defined with the phenazepam retention time of 7.05 ± 0.06 min; specific ions (m/z) 179, 183, 206, 242, 271, 285, 320, 348 (main) were defined for identification of phenazepam.

Biomedical support is aimed at provision of the athletes' training at various stages of the training and competition process. Withholding of access to this process due to health problems resulting from hepatitis virus infection is a demanding task. The study was aimed to assess the detection rate of the hepatitis B virus, hepatitis C virus and TT virus infection markers in highly trained athletes. A total of 384 blood serum samples were collected from 240 males and 144 females aged 14–49 (athletes engaged in playing sports, precision sports, technical sports, etc.) within the framework of the multicenter open-label cross-sectional clinical trial. All athletes answered a questionnaire, which included demographic information, characteristics of sports, information about the infection risk factors, information about the fact of  past acute viral hepatitis and vaccination. Markers of infection with hepatitis B virus, hepatitis C virus and TTV were identified in blood serum by enzyme immunoassay. HbsAg was detected in two surveyed athletes. Anti-HBcore (surrogate marker of latent HBV infection) was detected in 7% of samples (27/384); 1% of athletes (4/384) had a positive hepatitis C virus total antibody test (anti-HCV). Аnti-HCV in combination with anti-HBcore was detected in one female athlete (14 years of age, tennis player). DNA of TTV, TTMDV and TTMV was detected in blood serum samples of 89.1%, 83.1% and 85.4% of athletes, respectively. High detection rate of the hepatitis virus markers was observed.

Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus and one of the major causes of blindness in the developed world. Retinal laser photocoagulation is a gold standard for the treatment of DR. Despite its high efficiency, laser therapy has a number of limitations. The emergence of drugs, designed to inhibit the growth of the newly formed blood vessels, in ophthalmic practice made it possible to change treatment strategy in patients with retinal neovascularization. However, this method also has some adverse effects. Given the limitations on the repeated sessions of laser photocoagulation and the risks of ophtalmic complications after the intravitreal injection of the angiogenesis inhibitors, extraordinary situations, when there are negative results of treatment with the use of the described above techniques in one eye and disease progression in the single eye with preserved vision, become a serious problem when performing treatment. The clinical case reported has shown the feasibility of staged laser treatment in patient with the optic disc peripapillary neovascularization. Therapy has resulted in the regression of the newly formed blood vessels and visual function preservation.