Changes in the Number of Residual γH2AX Foci in Ki-67-Positive and Ki-67-Negative Human Fibroblasts Irradiated with X-Rays in Doses of 2-10 Gy

We studied changes in the number of residual γH2AX foci in cultured human fibroblasts with different expression of the cell proliferation marker protein Ki-67 24, 48, and 72 h after exposure to X-ray radiation in doses of 2-10 Gy. It was shown that, regardless of the expression of Ki-67, the number of residual γH2AX foci in irradiated cells linearly depends on the absorbed dose of X-ray radiation. However, the quantitative yield of residual γH2AX foci per unit of the absorbed dose in Ki-67+ cells 24 and 48 h after irradiation was higher than in Ki-67- cells by 1.8 and 2.0 times, respectively. In Ki-67- cells, the quantitative yield of residual γH2AX foci per unit of absorbed dose decreases by ~1.7 times with increasing the time after irradiation from 24 to 72 h. For the purposes of practical radiation biodosimetry, it can be recommended to quantify residual γH2AX foci in non-proliferating cells at least 72 h after irradiation.

Development of controlled nanosphere lithography technology

This work is devoted to the development of nanosphere lithography (NSL) technology, which is a low-cost and efficient method to form nanostructures for nanoelectronics, as well as optoelectronic, plasmonic and photovoltaic applications. Creating a nanosphere mask by spin-coating is a promising, but not sufficiently studied method, requiring a large experimental base for different sizes of nanospheres. So, in this work, we investigated the influence of the technological parameters of NSL by spin-coating on the substrate coverage area by a monolayer of nanospheres with a diameter of 300 nm. It was found that the coverage area increases with decreasing spin speed and time, isopropyl and propylene glycol content, and with increasing the content of nanospheres in solution. Moreover, the process of controllably reducing the size of nanospheres in inductively coupled oxygen plasma was studied in detail. It was determined that increasing the oxygen flow rate from 9 to 15 sccm does not change the polystyrene etching rate, whereas changing the high-frequency power from 250 to 500 W increases the etching rate and allows us to control the decreasing diameter with high accuracy. Based on the experimental data, the optimal technological parameters of NSL were selected and the nanosphere mask on Si substrate was created with coverage area of 97.8% and process reproducibility of 98.6%. Subsequently reducing the nanosphere diameter lets us obtain nanoneedles of various sizes, which can be used in field emission cathodes. In this work, the reduction of nanosphere size, silicon etching, and removal of polystyrene residues occurred in unified continuous process of plasma etching without sample unloading to atmosphere.

OES diagnostics as a universal technique to control the Si etching structures profile in ICP

In this work, we demonstrate the high efficiency of optical emission spectroscopy to estimate the etching profile of silicon structures in SF₆/C₄F₈/O₂ plasma. The etching profile is evaluated as a ratio of the emission intensity of the oxygen line (778.1 nm) to the fluorine lines (685.8 nm and 703.9 nm). It was found that for the creation of directional structures with line sizes from 13 to 100 μm and aspect ratio from ≈ 0.15 to ≈ 5 the optimal intensities ratio is in the range of 2–6, and for structures from 400 to 4000 μm with aspect ratio from ≈ 0.03 to ≈ 0.37 it is in the range 1.5–2. Moreover, the influence of the process parameters on the etching rate of silicon, the etching rate of aluminum, the inclination angle of the profile wall of the etched window, the selectivity of silicon etching with respect to aluminum, and the influence on the overetching (Bowing effect) of the structure was investigated.

[Forensic medical characteristics of fatal injuries in a traffic accident in the car cabin]

The study objective is to identify the most common fatal injuries in car accidents and observe the trends of the proportion of deaths at the scene, in an ambulance, and a hospital. We analyzed all forensic examination reports (protocols) of those who died in the car due to a traffic accident in Moscow from 2018 to 2020. Male drivers died 15 times more often than female drivers, and male passengers died twice as often as females. Most of the victims were young and middle-aged. Both drivers and passengers most commonly had traumatic brain injury with fractures of the bones of the vault and base of the skull, intracranial hemorrhages, crushing, and dislocation of the damaged brain. At the scene of traffic accidents, the cause of death was fatal bodily injuries. An increased risk of fatal traffic accidents was identified in autumn and winter.

Comparative Study of the γH2AX Foci Forming in Human Lung Fibroblasts Incubated in Media Containing Tritium-Labeled Thymidine or Amino Acids

We compared the formation of γH2AX foci (marker of DNA double-strand breaks) in human lung fibroblasts (MRC-5 line) during their 24-h incubation in a medium containing ³H-labeled thymidine or amino acids (glycine, alanine, and proline) with specific radioactivity from 100 to 400 MBq/liter. A linear dependence of changes in the number of γH2AX foci on the specific radioactivity of the medium was revealed. The quantitative yield of DNA double-strand breaks under the influence of ³H-thymidine was more than 2-fold higher than under the influence of ³H-labeled amino acids. Comparative analysis of the yields of DNA double-strand breaks during cell incubation with ³H-labeled amino acids showed that ³H-alanine produced more pronounced effect that ³H-proline, which is consistent with the data on the content of their non-radioactive analogs in chromatin proteins.

High-temperature Raman spectroscopy

Raman spectroscopy has a long-standing reputation as a powerful tool for structural investigation of the various materials. However, application of this technique to study the melt structure directly under high-temperature requires its certain modification. The methods of the registration of high-temperature Raman spectra were considered. Particular attention was paid to considering the systems on time-resolved filtering of the thermal radiation.

Comparative Analysis of the Formation of γH2AX Foci in Human Mesenchymal Stem Cells Exposed to 3H-Thymidine, Tritium Oxide, and X-Rays Irradiation

We performed a comparative study of the formation of γН2АХ foci (a marker of DNA doublestrand breaks) in human bone marrow mesenchymal stem cells after 24-h incubation with ³Н-thimidin and tritium oxide with low specific activities (50-800 MBq/liter). The dependence of the number of γH2AX foci on specific activity of 3H-thymidine was described by a linear equation y=2.21+43.45x (R²=0.96), where y is the number of γH2AX foci per nucleus and x is specific activity in 1000 MBq/liter. For tritium oxide, the relationship was described by a linear equation y=2.52+6.70x (R²=0.97). Thus, the yield of DNA double-strand breaks after exposure to ³H-thymidine was 6.5-fold higher than after exposure to tritium oxide. Comparison of the effects of tritium oxide and X-ray radiation on the yield of DNA double-strand breaks showed that the relative biological efficiency of tritium oxide in a dose range of 3.78-60.26 mGy was 1.6-fold higher than that of X-ray radiation. Improvement of the methods of analysis of DNA double-strand breaks repair foci is highly promising in the context of creation of highly sensitive biodosimetry technologies for tritium compounds in humans.

[PARTICIPATION OF AROMATIC MICROBIAL METABOLITES IN THE DEVELOPMENT OF SEVERE INFECTION AND SEPSIS.]

Background Actuality of the problem of infection in critically ill patients remains high. Addition a local infectious processes have a tendency to rapid generalization and sepsis. Neutrophilsfunction failure plays a key role in the patho- genesis of infectious complications and sepsis. The hypothesis about the role of microbial metabolites in the formation of immunosuppression, in particular in the inhibition of phagocytic activity of neutrophils as the first line of defense against bacteria is acquiring more and more supporters. Among the microbial metabolites aromatic compounds, such as phenylcarbinol acid (PCA) are of particular interest. Their concentration in the blood reaches a maximum in case of generalized infection, and correlates with mortality in patients in critical conditions, and PCA biological activity confirmed by earlier researches in vitro. The purpose of the study was to reveal the relationship of the PCA with the severity of bacterial infections and to assess the effect of PCA on neutrophils phagocytic activity.

MATERIALS AND METHODS

At the first stage the levels of PCA (GCh-FID method) in the serum ofpatients (n=57) with a documented bacterial infection of varying severity, confirmed APACHE II and SOFA scales were analyzed comparing with healthy donors (n=72). During the second stage the effect of clinically-relevant concentrations of PCA on neutrophils phagocytic activity ofperipheral blood was analyzed in vitro.

RESULTS

The levels ofphenylacetic (PAA), phenyllactic (PLA), hydroxyphenylacetic (p-HPAA) and hydroxyphenyllactic (p-HPLA) acids in patients were significantly higher than in healthy donors, reaching the highest values in severe infection. High direct correlation of PCA levels with the indicators ofscales APACHE II and SOFA was detected. A significant decrease in the number ofphagocytic neutrophils under the influence PAA, p-HPAA and PLA was identified in vitro experiment on average 11%. The most significant influence p-HPAA, PLA and p-HPLA have made on the intensity of the neutrophils absorption capacity reducing this parameter by an average of 26%. Also noted that phenylpropionic acid (PPC) which is in blood of healthy donors, disappears in critical ill patients.

CONCLUSION

Phenolcarbonic acids level in the blood serum shows the severity of bacterial inflammatory process. Ex- periment in vitro shows that the PCA in clinically-relevant concentrations is able to suppress the neutrophilsphagocytic activity.

[Biological properties of some sepsis-associated low molecular aromatic microbial metabolites]

Physico-chemical and biological properties of sepsis-associated low molecular aromatic compounds are summarized and analysed in the review. Phenylcarbonic acids (PCAs), such as para-hydroxyphenyllactic acid (p-HPLA), phenyllactic acid (PLA), para-hydroxyphenylacetic (p-HPAA), phenylacetic acid (PAA), benzoic acid (BA), and phenylpropionic acid (PPA) are shown to have biorequlatory activity and be able to affect both bacteria and eukaryotic cells. In the review there are presented data on the diagnostic and pathogenetic value of PCAs, their bacteriostatic and bacteriocidal properties and biosynthesis by clinically significant bacterial species, as well as description of the mechanisms of microbial resistance to PCAs, the pathways of PCAs metabolism by prokaryotes, PCAs membrane transport and excretion pathways in humans, the data on the use of PCAs in clinical practice. The authors are of the opinion that PCAs of microbial origin share the metabolic and signal pathways in integration of the microbiome and man. On the basis of the literature data and personal studies the authors validated the hypothesis of possible development of new therapeutic strategies, grounded on regulation of the local and systemic balance of aromatic microbial metabolites in the human body.

[Electrostatic map of bacteriophage T7 genome. Comparative analysis of electrostatic properties of sigma70-specific T7 DNA promoters recognized by RNA-polymerase of Escherichia coli]

The distribution of the electrostatic potential of T7 bacteriophage genome has been calculated. Promoter sites were localized in the electrostatic profile of T7-DNA. The electrostatic patterns of sigma70-specific promoters interacting with Escherichia coli RNA-polymerase were analyzed and compared with their functional behavior. Some specific electrostatic motifs were found in the upstream region of the promoters that may be involved in the differential recognition of promoter DNA by RNA-polymerase.

[Analysis of the distribution of the nucleotide sequence and electrostatic potential of the Escherichia coli genome]

The oligonucleotide composition of the E. coli genome and its sigma70-specific promoters has been analyzed. The promoter DNA was shown to contain mainly AT-rich hexanucleotides having functionally important physical properties such as the ability to form easily melting sites and induce the bending of the double helix. A comparative analysis of the electrostatic characteristics of hexanucleotides within the whole sequence of the E. coli genome and its promoter regions was made. Hexanucleotides possessing a more electronegative surrounding were found to predominate in the nucleotide sequence of the promoter DNA.

[Regulation of promoter activity through electrostatic interactions with RNA-polymerase]

Electrostatic profiles for sigma70-specific promoters of T4 bacteriophage and four consensus-like synthetic promoters have been calculated. It was shown that the promoters can be classified according to the presence of some specific electrostatic elements located in the far upstream region of their DNAs. A correlation between the electrostatic elements specific for promoters and their functional behaviour was established. A general scheme of promotor activity regulation through electrostatic interactions between the upstream region of promoter DNA and the RNA-polymerase a-subunit was suggested.

[Some principles in the organization of sigma70-specific promoters on the E. coli genome on the basis of electrostatic patterns of promoter DNA]

The distribution of electrostatic potential of the complete sequence of the E. coli genome was calculated. It was found that DNA is not a uniformly charged molecule. There are some local inhomogeneities in its electrostatic profile, which correlate with the position of promoters in the genome. Electrostatic patterns of promoter DNAs can be specified due to the presence of some distinctive motifs, which may be involved as promoter signal elements in RNA-polymerase-promoter recognition.

[The etiological and pathogenetic bases of nephrolithiasis]

A new outlook on etiology and pathogenesis of nephrolithiasis regards renal tubular acidosis (RTA) as the basic pathogenetic factor of nephrolithiasis. These conclusions were made basing on the findings on blood and urine glycolysis enzymes, lactic acid, acid-base metabolism, titrated acids, ammonium. RTA stages responsible for the variety of the forming concrement and two groups of nephrolithiasis etiological factors (acting on epithelial cell of the nephron and involved in urinary processes) are distinguished.