Introduction. Convalescent COVID-19 patients have various signs of central nervous system damage, including those directly associated with SARS-CoV-2. Hence, studies of SARS-COV-2 related morphological changes in neocortex are particularly relevant for understanding the mechanisms of their formation and development of approaches to preclinical evaluation of the effectiveness of antiviral drugs. The purpose of the research is a longitudinal study of the ultrastructural alterations in Syrian hamsters neocortex after experimental SARS-CoV-2 infection. Materials and methods. Male Syrian hamsters weighing 80100 g, aged 4 to 6 weeks, were infected with 26 l SARS-CoV-2 intranasally with 4104 TCD50/ml of viral particles. The animals were euthanized on days 3, 7 or 28 post-infection, the brain was extracted with the cortex excision. The material analysis was performed using transmission electron microscopy. Results and discussion. On day 3 post-infection, the number of moderately hyperchromic neurons in neocortex increased, while by the day 7 the number of apoptotic cells significantly increased. Simultaneously, an increased signs of neuronophagy and representation of atypical glia were observed. Increased number of altered oligodendrocytes was observed on day 28 post-infection. Viral invasion was accompanied by changes in neocortical cells since day 3 post-infection, such as transformation of their nucleus, the rough endoplasmic reticulum and the Golgi vesicles as well as microvascular spasm with perivascular edema. Conclusion. As a result of electron microscopic study, the ultrastructural alterations in neocortex were described in an experimental model of SARS-CoV-2 infection. The findings can be used to identify the mechanisms of infection pathogenesis and to search for the new directions in development of medicines.
Introduction. In experimental toxicology, the selection of criteria characterizing the toxicological process play an important role in evaluating the effectiveness of the means of prevention and treatment of intoxication. Aim of the study: study of the dynamics, informativity and prognostic significance of rectal temperature at sulfur mustard intoxication in rats. Results of the study. The results showed that intramuscular injection of sulfuric mustard in rats in the range of doses from minimally lethal to absolutely lethal is accompanied by a dose-dependent decrease in rectal temperature at 3-days of intoxication. In the studied sample, the dividing capacity (AUC) of the rectal temperature index at the intoxication peak (3-d day) for mortality was 0,94 (95 % CI 0,8–0,91), which corresponds to excellent predictive ability. The sensitivity and specificity parameters for rectal temperature were 0,86 (95 % CI 0,8–0,91) and 0,90 (95 % CI 0,83–0,95), respectively. Conclusions. Rectal temperature values reflect the dynamics and severity of sulfur mustard intoxication in rats. This criterion has a high informative and predictive value in relation to the death and can be reasonably included in the program of evaluation of the effectiveness of the developed means of prevention and treatment of sulfur mustard.
Sulfur mustard (SM) is a highly toxic blistering agent (vesicant) that has been widely used as a chemical weapon in wars and armed conflicts. Not only highly effective antidotes, but also tools for pathogenetic therapy of SM-induced lesions currently are not available, which necessitates further research in this field. Aim of the study: to examine the morphofunctional changes in gastrointestinal tract of rats during SM intoxication. Materials and methods. In experiments on rats during SM intoxication the severity of diarrhoea, propulsive activity and the specific mass of gastrointestinal tract were assessed, as well as performed a pathomorphological study of the small intestine. Results of the study. The obtained data indicate the development of the combined motor-evacuation, barrier, secretory-absorption and digestive intestinal dysfunction during SM intoxication. Conclusions. According to the authors, syndrome of intestinal insufficient is an important component of patho- and thanatogenesis of SM intoxication. Moreover, fluid sequestration and endocavitary pressure increase in gastrointestinal tract, which develop in consequence of its functional inability, should be considered as additional pathogenetic components of intoxication.
Pathogenic microorganisms and products of their metabolism, namely, bacterial protein exotoxins, are considered one of the main sources of biological threat. Microbial toxins are highly active and extremely dangerous to humans. Determining trace amounts of such compounds remains relevant in healthcare and biological protection sector. Timely qualitative- and quantitative-specific indication of biotoxins is a key component in the diagnosis and implementation of therapeutic and preventive measures. Pathogenic microorganisms and products of their metabolism, bacterial protein exotoxins, are considered one of the main sources of biological threat. Microbial toxins are highly active and extremely dangerous to humans. Determining trace amounts of such compounds remains relevant in healthcare and biological protection sector. Timely qualitative- and quantitative-specific indication of biotoxins is a key component in the diagnosis and implementation of therapeutic and preventive measures. The current state and prospects of development in formulating specific indications of microbial toxins that disrupt protein synthesis in cells are analyzed. Modern ideas about the structure and mechanism of action of these toxins are briefly presented. Possibilities were considered, the advantages and disadvantages of classical traditional and modern innovative methods for identifying bacterial toxins that inhibit protein synthesis in cells were compared, and classifications were provided. Examples of the use of various approaches to identify the most significant representatives of this group in both clinical material and in environmental objects, including regulated ones, were given. The review also listed modern domestic and foreign developments in formulating specific indications of microbial toxins inhibiting protein synthesis. The review summarizes the results of studies to determine the current directions in the development of tools and methods for rapid specific indication of microbial toxins. The main trends in the creation of new methods of toxicological screening as part of an effective national system for monitoring biological threats were analyzed. Prospects for the development and introduction to the market of domestic test systems and automatic analysis platforms for the detection of bacterial toxins in environmental objects and biological material were determined.
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