EEG Microstate Analysis and the EEG Inverse Problem Solution as a Tool for Diagnosing Cognitive Dysfunctions in Individuals Who Have Had a Mild Form of COVID-19.

The term "postcovid syndrome" is firmly entrenched in medical terminology, however, many aspects of its clinical manifestations are not well understood. The aim of this work was to find the causes of the development of cognitive dysfunctions in individuals who had a mild form of SARS-CoV-2 using high-density EEG technology and solving an inverse neurophysiological problem. A dynamic study was conducted of 38 people who had COVID-19 and returned to work. Neurophysiological studies were carried out using the EGI-GES-300 system (128 channels). The descriptive characteristics of electroencephalograms were built on the method of studying the spectral density of the EEG signal on the surface of the scalp, and the dynamic characteristics of the signal were studied by fixing EEG microstates, using the method of D. Lehmann and T. Koenig (2018). In the study, a relatively new diagnostic technique for studying cognitive impairments based on the analysis of EEG microstates was implemented, which made it possible to identify signs of functional restructuring of the neuronal macronetworks of the brain and trace the characteristic adaptation of a person during the period of convalescence. The results obtained made it possible to detect a violation of the implementation of the speech function, as a violation of the perception system (ventral information flow system), as well as the connection between the fields of Wernicke's center and Broca's center (dorsal information flow system), leading to the development of communicative dysfunctions that cause characteristic clinical symptoms due to impaired perception of new information and difficulties in implementing the solution. Thus, the survey showed that SARS-Co-V2 causes objective changes in the functional activity of the brain, which are manifested by the syndrome of cognitive dysfunction and require the development of more sensitive clinical tests than currently used.

Preclinical Studies of Immunogenity, Protectivity, and Safety of the Combined Vector Vaccine for Prevention of the Middle East Respiratory Syndrome.

The Middle East Respiratory Syndrome (MERS) is an acute inflammatory disease of the respiratory system caused by the MERS-CoV coronavirus. The mortality rate for MERS is about 34.5%. Due to its high mortality rate, the lack of therapeutic and prophylactic agents, and the continuing threat of the spread of MERS beyond its current confines, developing a vaccine is a pressing task, because vaccination would help limit the spread of MERS and reduce its death toll. We have developed a combined vector vaccine for the prevention of MERS based on recombinant human adenovirus serotypes 26 and 5. Studies of its immunogenicity have shown that vaccination of animals (mice and primates) induces a robust humoral immune response that lasts for at least six months. Studies of the cellular immune response in mice after vaccination showed the emergence of a specific CD4+ and CD8+ T cell response. A study of the vaccine protectivity conducted in a model of transgenic mice carrying the human DPP4 receptor gene showed that our vaccination protected 100% of the animals from the lethal infection caused by the MERS-CoV virus (MERS-CoV EMC/2012, 100LD50 per mouse). Studies of the safety and tolerability of the developed vaccine in rodents, rabbits, and primates showed a good safety profile and tolerance in animals; they revealed no contraindications for clinical testing.

Assessment of the Parameters of Adaptive Cell-Mediated Immunity in Naïve Common Marmosets (Callithrix jacchus).

Common marmosets are small New World primates that have been increasingly used in biomedical research. This report presents efficient protocols for assessment of the parameters of adaptive cell-mediated immunity in common marmosets, including the major subpopulations of lymphocytes and main markers of T- and B-cell maturation and activation using flow cytometry with a multicolor panel of fluorescently labelled antibodies. Blood samples from eight common marmosets were stained with fluorescently labeled monoclonal antibodies against their population markers (CD45, CD3, CD20, CD4, CD8) and lymphocyte maturation and activation markers (CD69, CD62L, CD45RO, CD107a and CD27) and analyzed by flow cytometry. Within the CD45+ population, 22.7±5.5% cells were CD3- CD20+ and 67.6±6.3% were CD3+CD20-. The CD3+ subpopulation included 55.7±5.5% CD3+CD4+CD8- and 34.3±3.7% CD3+CD4-CD8+ cells. Activation and maturation markers were expressed in the following lymphocyte proportions: CD62L on 54.0±10.7% of CD3+CD4+ cells and 74.4±12.1% of CD3+CD8+ cells; CD69 on 2.7±1.2% of CD3+CD4+ cells and 1.2±0.5% of CD3+CD8+ cells; CD45RO on 1.6±0.6% of CD3+CD4+ cells and 1.8±0.7% of CD3+CD8+ cells; CD107a on 0.7±0.5% of CD3+CD4+ cells and 0.5±0.3% of CD3+CD8+ cells; CD27 on 94.6±2.1% of CD3+ cells and 8.9±3.9% CD20+ cells. Female and male subjects differed in the percentage of CD3+CD4+CD45RO+ cells (1.9±0.5 in females vs 1.1±0.2 in males; p < 0.05). The percentage of CD20+CD27+ cells was found to highly correlate with animals' age (r = 0.923, p < 0.005). The basal parameters of adaptive cell-mediated immunity in naïve healthy marmosets without markers of systemic immune activation were obtained. These parameters and the described procedures are crucial in documenting the changes induced in common marmosets by prophylactic and therapeutic immune interventions.