Despite the enormous interest in COVID-19, there is no clear understanding of the mechanisms underlying the neurological symptoms in COVID-19. Microglia have been hypothesized to be a potential mediator of the neurological manifestations associated with COVID-19. In most existing studies to date, morphological changes in internal organs, including the brain, are considered in isolation from clinical data and defined as a consequence of COVID-19. We performed histological immunohistochemical (IHC) studies of brain autopsy materials of 18 patients who had died from COVID-19. We evaluated the relationship of microglial changes with the clinical and demographic characteristics of the patients. The results revealed neuronal alterations and circulatory disturbances. We found an inverse correlation between the integral density Iba-1 (microglia/macrophage-specific marker) IHC staining and the duration of the disease (R = −0.81, p = 0.001), which may indicate a reduced activity of microglia and do not exclude their damage in the long-term course of COVID-19. The integral density of Iba-1 IHC staining was not associated with other clinical and demographic factors. We observed a significantly higher number of microglial cells in close contact with neurons in female patients, which confirms gender differences in the course of the disease, indicating the need to study the disease from the standpoint of personalized medicine.

The aim of the study was to develop a prematurity score model for predicting morbidity in premature infants in the neonatal period. Material and methods. To build an analytical model, such parameter as gestational age is used, measured in weeks with the range of changes in the score between 0 to 10, where a score of 38 - 40 weeks should correspond to 0 points, i.e., at this gestational age, the morbidity rate due to morphological immaturity of organs and systems is minimal, because by this gestational age the organ development is almost completed. The maximum score is 9.9, at gestational age of 22 weeks, which is associated with severe morphological immaturity and, therefore, high morbidity in a premature infant. Results. Based on mathematical calculations, we built a model of prematurity score, which helps estimate the degree of abnormality of a premature baby depending on gestational age. The lower it is, the higher is the score of prematurity and the likelihood of morbidity due to morphological immaturity of organs and systems. Conclusion. The proposed analytical model of prematurity score can be used to uniformly assess the prematurity factor in order to further determine the medical strategy. The model can be effectively used in scientific research and to identify statistically necessary relationships in a wide variety of studies. The main value of the model lies not in obtaining specific numerical values, but in the suggested analytical relationship reflecting the degree of morphological maturity and allowing probability estimation of the newborn morbidity.

Better understanding of ischemic brain injury mechanisms is important for the development and improvement of diagnostic and therapeutic modalities for management of ischemic stroke. As experimental studies are on demand, there’s a need for relevant models of focal brain lesions. Photochemically induced thrombosis remains one of the most popular models of ischemic stroke.The purpose of the review is to consider the pathogenesis and applicational relevance of the photochemical thrombosis in ischemic stroke modeling.Material and methods. The information was searched using PubMed and Google Scholar databases and keywords «photothrombotic stroke» without language restrictions. 74 papers out of more than 600 sources were found the most relevant for the purpose of this review and selected for the analysis. Of these, more than 50% have been published in the last five years. The criterion for excluding a source was an inconsistency with the objectives of the review and low information content.Results. We outlined a variety of features in modeling photothrombotic stroke, analyzed the advantages and disadvantages of the model, presented data on current method’s modifications, as well as approaches to evaluation of brain lesions in ischemic stroke induced by photothrombosis, and summarized information about the mechanisms of brain damage induced in this model.Conclusion. Several advantages of the photothrombotic stroke model, such as low invasiveness, high reproducibility, inherent control of brain infarction volume and low mortality, determine its active use in experimental studies of ischemic stroke. Pathological processes in the brain modeled by photochemical thrombosis are similar to the processes occurring in acute ischemic cerebral circulation events. Therefore, this model provides insights into cellular and molecular mechanisms of ischemic brain damage, and can be used for developing novel therapeutic approaches for management of ischemic stroke.