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Extreme Medicine

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Skeletal muscle plasticity is the ability to change morphofunctional properties in response to changes in contractile activity. Strength training increases the size of muscle fibers and maximum strength with the activation of protein synthesis. Regulation of these changes at the gene level has not been investigated properly. This study aimed to identify transcription factors associated with changes in the transcriptome of the human skeletal muscle in the context of single and regular strength exercises. We assessed changes in the transcriptomic profile of m. vastus lateralis of 10 young men (mean age 23 (20.8 - 25.9) years) before and after 12-week leg extensor muscles strength training course, as well as before, 8 and 24 hours after a single exercise. Transcriptomic profiling involved RNA sequencing, search for binding motifs and the associated transcription factors. Bioinformatic methods of statistics, FastQC, GraphPad Prizm 8, DAVID, R enabled analysis of the data acquired. The strength training course resulted in the enrichment of the functional groups of genes "secreted proteins", "extracellular matrix" and "basal membrane" (p < 0.05). Transcriptomic responses and the associated transcription factors differed 8 and 24 hours after a single session as well as after regular training sessions. Transcription factors involved in adjustment to regular and one-time loads participate in myogenesis, angiogenesis, regulation of fiber phenotype, proteostasis and other processes. Thus, regulation of gene expression during adjustment to the resistance training loads is a complex process that involves many transcription factors with different functions. Investigation of the role played by these factors in the context of adjustment to exercising is a potentially rewarding task.
For residents of territories along the Techa River that was contaminated with radioactive substances in the 1950s, bone-seeking beta-emitting 89,90Sr were the main source of internal exposure of active (red ) bone marrow (AM). The dose of these radionuclides conditions the severity of leukemia risk for them. Improvement of the methods of internal AM dosimetry is an important task. Computational 3D phantoms of the skeleton sites are a component of the solution for this task. Simulation of radiation transfer in a heterogeneous bone model allows estimating the dose conversion factors from radionuclide activity to AM dose. This manuscript continues the series of papers covering the development of a set of computational phantoms of a reference human being of different age. The objective of the study was to develop a computational phantom of a one-year-old child skeleton for internal AM dosimetry (exposure due to incorporated beta emitters). Using the original SPSD (stochastic parametric skeletal dosimetry) model, we develop voxel 3D models of skeletal sites. Skeleton sites with active hematopoiesis were modeled as a set of phantoms of simple geometries. Distribution of AM throughout the skeleton and parameters of the phantoms were assessed on the basis of the published results of measurement done in real bones of children aged 9 months to 2 years. The generated computational phantom of a one-year-old child consisted of 39 segments. It simulates the structure of the bone tissue, location of AM, and population variability of the skeleton microstructure and size parameters.
According to the available data, the effect of high doses of ionizing radiation on the human central nervous system (CNS) takes form of cognitive dysfunction and increased risk of development of malignant neoplasms. At the same time, there is a growing concern about the possible effects of low, moderate doses of ionizing radiation and chronic irradiation, on cognitive functions, as well as their potential long-term consequences manifesting as neurodegenerative diseases. There is both epidemiological and experimental evidence confirming that low and moderate doses of ionizing radiation affect cognitive abilities. The underlying mechanisms include disruption of normal neurogenesis in the hippocampus, development of long-term sustained neuroinflammation, disorders of synaptic plasticity, energy metabolism, and oxidative status. On the part of CNS, the body is most sensitive to radiation during the period of active formation of the brain. Irradiated at that time, people may suffer consequences thereof for several months and years, or have them manifesting only much later, in old age. Improvement of radiation safety and development of means and ways of prevention and treatment of radiation-induced CNS disorders require further research efforts aimed at establishing causal relationships between chronic exposure to radiation and low-dose irradiation and their adverse effects on the part of CNS in the long term post-exposure.

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Curiosity about the activity of neural networks in the human brain results from the search for definition of human self-consciousness as an identifier of human personality. Today, the RS-fMRI technology occupies a leading position among methods used to study this problem. The widespread use of the technology is limited by certain drawbacks. Starting from 2010, there is a growing interest in the possibility of using neurophysiological methods for the diagnosis of the brain's default mode network (DMN) state based on the analysis of EEG microstates. The study was aimed to demonstrate the possibility of recording the activity of brain networks both at rest and under exposure to the stimulus evoking a known response. A total of 42 people underwent assessment in the relaxed wakefulness state with the eyes closed that involved extraction of certain EEG microstate sequences and the EEG inverse problem solution. The data obtained were tested for adequacy via comparison with the results obtained by the preset stimulation of auditory and language function. The conclusion was made about the possibility of assesing the brain's DMN’s activity by combining the analysis of EEG microstates with the EEG inverse problem solution. The proposed technology can be used in both scientific research and clinical practice in the form of new techniques and systems allowing one to determine alterations in neuropsychological processes.