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

New articles

Today, the cell-based technologies are one of the instruments used for the cartilage tissue repair. Creation of a universal hypoimmunogenic cartilage tissue graft from the differentiated derivatives of induced pluripotent stem cells (iPSCs) might solve the problem of the lack of the cartilage cell product. However, currently there is little data on immunogenicity of such tissue-engineered preparations. The study was aimed to create a cartilage implant from the differentiated derivatives of the B2M-deficient iPSCs and assess its immunogenicity. The previously developed protocol was used to ensure differentiation of both wild-type and B2M knockout iPSCs into chondrocyte-like cells. After quality control of the resulting cell lines by conducting polymerase chain reaction and immunocytochemical assessment, the resulting cell lines were co-cultured with the peripheral blood mononuclear cells of a healthy donor. When co-cultivation was over, activation and degranulation of CD8+ T cells was assessed by flow cytometry analysis based on the CD69 and CD107a expression on the cell surface, respectively. The iPSC-derived chondrocytes expressed the cartilage tissue markers. Flow cytometry analysis revealed no substantial differences in immunogenicity between the derivatives of wild-type and B2M knockout iPSCs, as well as from the cartilage tissue cells of a healthy donor. Immunogenicity of chondrocyte-like cells was higher than that of hypoimmunogenic non-edited iPSCs. The B2M knockout iPSCs demonstrated a trend towards greater activation of CD8+ T cells. Thus, the B2M knockout in the iPSC-derived chondrocytes had no significant effect on the tissue immunogenicity. It is necessary to further edit the genes encoding MHC II and CD47 to obtain a less immunogenic product.
Community-acquired pneumonia (CAP) is a major cause of pediatric morbidity and mortality. Currently, there is no common approach to determination of CAP severity in children, which hampers early diagnosis and treatment of the disease. The study was aimed to determine clinical and laboratory predictors of severe CAP in children under 4 years of age. Analysis of clinical data, parameters of complete blood count (CBC), C-reactive protein (CRP) using nonparametric methods for hypothesis testing, univariate correlation analysis, cross-tabulation (Statistica 10.0), logistic regression, and ROC analysis (SPSS Statistics 20.0) was performed in 72 children aged 1 month to 3 years 11 months admitted to hospital due to CAP. Severe CAP was diagnosed in 16.7% of children. Causes of severe CAP included respiratory distress (moderate — 58.3%, severe — 16.7% of cases) and sepsis (25%). We identified significant clinical predictors of severe CAP: vomiting (OR 4.2), tachypnea (OR 28.3), chest wall retractions (OR 6), wheezing (OR 4), and the absence of rhinitis (OR 0.21). Isolated assessment of the CBC and CRP did not allow to predict CAP severity. We have developed a prediction model predicting severe CAP in children under 4 years of age based on the presence of rhinitis, tachypnea, as well as leukocyte count (sensitivity and specificity 91.7%). Thus, currently the main cause of severe CAP in children under 4 years of age is respiratory distress, in which wheezing predominates. Physical examination with an emphasis on detection of rhinitis and respiratory distress is essential for diagnosing severe CAP. The use of a pneumonia severity prediction model may contribute to improvement of management of CAP in patients under 4 years of age.
The growing proportion of antibiotic-resistant Klebsiella pneumoniae strains raises challenges to the healthcare system and requires the development of alternative treatment options. Bacteriophage therapy is one of such options. The study was aimed to isolate and describe bacteriophages effective against K. pneumoniae strains of clinically significant capsular types. The bacteriophages were isolated from the sewage and river water samples using the enrichment culture technique. The spectrum of lytic activity of the phages was tested on the collection of K. pneumoniae clinical isolates (n = 279). The studied bacteriophages lysed 52.8–100% of K. pneumoniae strains of respective capsular types: phage VKV295 lysed 100% of strains with the capsular type KL1, SAA231 — 52.8 of strains with KL2, NNK-G4 — 100% of strains with KL39, VSG32 — 66.7% of strains with KL41, NKA196 — 87.5% of strains with KL47, Rappa3 — 87.5% of strains with KL57, PEA128 — 95.5% of strains with KL64, and ChM-G5 — 69.6% of strains with KL102. Whole-genome sequencing and subsequent bioinformatic analysis revealed that the phages belong to the Autographiviridae family and are classified into three genera.The lytic spectrum of phages was limited to specific capsular types due to the presence of specific receptor-binding proteins, polysaccharide depolymerases. The isolated bacteriophages were strictly virulent, did not carry harmful genetic determinants, and had a specific host range, making them applicable in therapeutic practice for combating antibiotic-resistant infections caused by K. pneumoniae.

Popular articles

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.
The model of severe poisoning with acetylcholinesterase inhibitors has shown the possibility of drug treatment of toxic effects with valproic acid containing a tertiary amino group. The study was aimed to assess potential mutagenic effects of the valproic acid derivative containing a tertiary amino group when studing its safety. Testing for toxicophores and assessment of the mutagenic effect probability were perfomed using the QSAR Toolbox offline software (v4.5 SP1). The Ames test with and without metabolic activation was used to estimate mutagenic potential of valproic acid containing a tertiary amino group in vitro. The computer prediction results predicted that the test substance would show no mutagenic effects in the Ames test. These data were confirmed by the in vitro Ames test for a broad range of concentrations of valproic acid containing a tertiary amino group (0.02–5.0 mg/mL). The concentrations of valproic acid containing a tertiary amino group exceeding 1.58 mg/mL have a bacteriostatic effect on the TA 100 S. typhimurium strain and the WP2 uvr A pKM 101с E. coli strain. Thus, the valproic acid derivative containing a tertiary amino group possesses no mutagenic effect, it can be recommended for further preclinical trials of therapeutic efficacy and safety.