ISSN Print 2713-2757    ISSN Online 2713-2765
Extreme Medicine

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Assessment of individual responses of cells, tissues and the whole body to radiation exposure is an important challenge for radiobiology and radiation safety. The study was aimed to develop the method for estimation of the human hematopietic stem cell (HSC) individual response in the humanized mouse model. The cord blood or peripheral blood HSCs were administered to the NOD SCID immunodeficient mice. The number of maturing HSCs (CD34+ cells) and mature CD45+ leukocytes was assesed after the acute gamma exposure to the doses of 0.5 Gy, 1 Gy, and 1.5 Gy, along with the HSC share among all CD45low/+ cells within three days (period of maximum mortality) and 14 days (period of active restoration) after exposure. The relationship between the indicato values and the exposure dose was calculated by regression analysis. There was exponential relationship between the human HSC survival rate in humanized mice and the dose on day three after exposure (R2 = 0.93; F = 211; p < 0.01), while the relationship between the number of HSCs and the dose on day 14 after exposure was linear (R2 = 0.65; F = 12.9; p = 0.01). The C14/3 coefficient calculated as a ratio of the HSC share among all human CD45low/+ cells on day 14 after exposure to the same parameter on day three after exposure was proposed as an indicator of HSC mortality and HSC number restoration. C14/3 negatively correlated with the exposure dose (R2 = 0.57; F = 13.3; p = 0.004), it was higher in radioresistant mice and the model of  cysteamine-induced radioresistance in humanized mice. The model mice humanized using the peripheral blood HSCs can be used to assess individual HSC response to acute external gamma exposure based on C14/3 and the data on the HSC survival and restoration.
Mathematical modeling is a promising method enabling in silico calculations with subsequent suggestion of cell membrane protective agents used to reduce the consequences of exposure to hydrogen sulfide-containing gas in emergency situations. This study aimed to investigate the nature of interaction of hydrogen sulfide (H2S) and N-Acetyl-L-Cycteine (NAC) with the components of cell membranes. We built a mathematical model of interatomic interactions of cell membrane components with H2S and NAC (two separate models), then made the quantum-chemical calculations using our proprietary technique and set up GAMESS Z-matrices reflecting type and position of atoms in the molecules. The structure of the molecules was optimized with the help of MOPAC package built into ChemOffice. Lecithin-based liposomes in a sulfide solution (with Na2S being the donor of H and HS ions) were used as an experimental model of the biological membrane. Redox potential in mV was the comparison parameter in assessment of interaction of the H2S system components and NAC with phospholipid. The results include patterns showing the phospholipid reactive centers blocked by NAC under toxic exposure to H2S. Liposomal models of cell membranes were formed and redox parameters measured. Biological experiment confirmed the acceptable accuracy of the designed method of calculation of intermolecular interactions when used as a basis for further selection of agents capable of adjusting toxic doses of hydrogen sulfide. Membrane models of H2S interaction with protein and lecithin were visualized in silico and in vitro. The possibility of using NAC as an H2S inhibitor has been confirmed.
Chronic hepatitis B (CHB) is a common infectious disease that represents one of the main causes of liver cirrhosis (LC) and hepatocellular carcinoma (HCC). CHB is still difficult to treat due to  the lack of drugs that completely eliminate hepatitis B virus (HBV) from hepatocytes. The study was aimed to describe the CHB clinical and laboratory features, assess the efficiency of antiviral therapy and identify the factors associated with the response to antiviral therapy. The results of clinical and laboratory assessment, instrumental examination, serological and molecular testing of the patients (n = 201) followed up between 2007–2021 in the Viral Hepatitis Diagnosis and Treatment Center at the Clinical Hospital No. 85 of FMBA of Russia were assessed based on primary sources. Most of the patients in the group were males (56.7%); the HBeAg-negative patients predominated (93%). LC was diagnosed in nine patients (4.5%), among them one patient had HCC. The HBV D genotype was determined in 95.4% of cases, А genotype in 3.1% of cases, and С genotype in 1.5% of cases. After a year of treatment with the nucleos(t)ide analogues (entecavir or tenofovir) 88% of patients showed no viremia and their biochemical parameters were back to normal (88%). The overall seroconversion rate was 41.7% for HBeAg and 3% for HBsAg. Thus, high rates of virological response and enzyme activity normalization were obtained. Low baseline viremia level is an independent prognostic factor of achieving a virological response. The HBsAg level in the end of therapy makes it possible to predict relapse after the treatment cessation. 

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One of the approaches to cartilage tissue restoration problem relies on cellular technologies that use iPSCs, induced pluripotency stem cells that are an unlimited source of cellular material for tissue engineering with significant differentiation potential. However, there are no standardized protocols for chondrogenic differentiation of iPSCs. This study aimed to make cartilage tissue samples using 3D spheroid cultures and following four chondrogenic differentiation protocols, then compare characteristics of the cartilage samples made under different protocols and isolate the most effective way of differentiation. The iPSCs were differentiated chondrogenically, the four protocols were "long", "short", "combined" and with conditioned medium from a primary culture of autologous chondrocytes; the combinations of TGFβ1, BMP2, Chir 99021, and PK factors varied. Microwell plates were used to make spheroids. Immunocytochemical staining, real-time PCR and histological staining enabled assessment of the synthesis and expression profiles. High rates of synthesis and expression of chondrogenic markers Sox9, aggrecan, type II collagen were observed in spheroids experimented with under the "long", "combined" protocols and the conditioned medium protocol. The "combined" differentiation protocol made chondrogenesis most effective, and conditioned medium was highly efficient in inducing and supporting chondrogenic differentiation.
The rapid switch on of the transient short-term responses involved in adjustment of homeostasis plays a key role in human adaptation to low temperatures that is essential for adjustment to low-temperature environment. The network of signaling pathways together with metabolic regulators provide sufficient plasticity of the cells of immune system, the normal function of which is extremely important for successful human adaptation. Sufficient energy supply to immunocompetent cells makes it possible to form an adequate immune response to any negative factor and to ensure adaptive functional rearrangements. The study was aimed to assess the variants of the immunocompetent cell metabolic pathways involved in acquiring individual cold sensitivity. A total of 180 people aged 25–55 (130 females, 50 males) were assessed before and after the short-term whole body cooling. Enzyme immunoassay was used to define the levels of IL10, IL6, TNFα, irisin, transferrin, sTfR, HIF-1α, Sirt3 in peripheral blood and cell lysate. The levels of glycogen (cytochemical methods) and ATP (luciferin-luciferase assay) in lymphocytes were defined. The decrease in peripheral blood lymphocyte levels after cooling was indicative of the formation of immediate adaptive response and activation of glycolysis amid less intense inflammatory response. The increase in the levels of circulating lymphocytes after the cold esposure was associated with activation of inflammatory responses. The lower ratio of HIF-1α/SIRT3 metabolic regulators was found in the surveyed volunteers who showed no changes in the levels of lymphocytes. This indicated predominance of mitochondrial activity in adaptation to low temperatures.