Bulletin of RSMU

ISSN Print 2500–1094 ISSN Online 2542–1204

Bulletin of RSMU

BIOMEDICAL JOURNAL OF PIROGOV UNIVERSITY (MOSCOW, RUSSIA)

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Suntsova AYu, Guliev RR, Popov DA, Vostrikova TYu, Dubodelov DV, Shchegolikhin AN, Laypanov BK, Priputnevich TV, Shevelev AB, Kurochkin IN

The need for novel techniques of rapid identification of pathogenic microorganisms arises from the massive spread of drug-resistant nosocomial strains and the emergence of centers for biohazard control. Fourier-transform infrared spectroscopy is a promising alternative to mass spectrometry as it is cost-effective, fast and suitable for field use. The aim of this work was to propose an algorithm for the identification of microorganisms in pure cultures based on the analysis of their Fourier transform infrared spectra. The algorithm is based on the automated principal component analysis of infrared spectra. Unlike its analogues described in the literature, the algorithm is capable of identifying bacteria regardless of the culture medium or growth phase. The training sample included the most prevalent causative agents of infections and sepsis in humans: Staphylococcus aureus (n = 67), Enterococcus faecalis (n = 10), Enterococcus faecium (n = 10), Klebsiella pneumoniae (n = 10), Escherichia coli (n = 10), Serratia marcescens (n = 10), Enterobacter cloacae (n = 10), Acinetobacter baumannii (n = 10), Pseudomonas aeruginosa (n = 10), and Candida albicans (n = 10). The model we built successfully passed a series of blind tests involving clinical isolates of 10 methicillin-resistant (MRSA) and 10 methicillin-sensitive (MSSA) Staphylococcus aureus strains as well as pair mixes of these cultures with clinical isolates of Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae.

Received: 2018-08-01

Published online: 2018-09-29

DOI: 10.24075/brsmu.2018.046

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VIEWS 5700

Vaneev AN, Alova AV, Erofeev AS, Gorelkin PV, Aleksashkin AD, Beznos OV, Chesnokova NB, Kost OA, Majouga AM, Korchev Y, Klyachko NL

Reactive oxygen species (ROS) are vital metabolites in numerous biological functions. Disorders of cellular mechanisms can cause overproduction of ROS and, subsequently, oxidative damage to DNA, proteins, cells and tissues, which is associated with the pathogenesis of a number of neurodegenerative and inflammatory diseases. Development of highly sensitive, relatively simple and fast-to-implement innovative methods to detect oxidative stress requires understanding of how such disorders relate to the level of ROS. This research aimed to apply the biological fluids' ROS detection method we have developed (using the stable platinum nanoelectrode that allows assessing the level of hydrogen peroxide (H2O2) down to 1 μM) and determine the level of H2O2 in lacrimal and intraocular fluids of rabbits, as well as to investigate how the level of H2O2 changes under the influence of antioxidant therapy. The effect superoxide dismutase (SOD) nanoparticles produce on biological fluids' ROS level was shown. The level of H2O2 in lacrimal fluid increased 10 and 30 min after instillation of SOD nanoparticles. As for the intraocular fluid, H2O2 concentration starts to grow only 30 min after instillation of SOD nanoparticles, which suggests that the they penetrate the internal structures of the eye gradually. The method seems to be of value in the context of eye diseases diagnosing and treatment.

Received: 2018-06-28

Published online: 2018-09-28

DOI: 10.24075/brsmu.2018.045

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VIEWS 5334

Kurnosova OP, Odoevskaya IM, Petkova S, Dilcheva V

Toxocariasis is the type of helminthic infection found in dogs and cats most often. It is a zoonotic disease that presents a serious threat to the national public health. Urban environment favors transmission of toxocara from animals to people; soil is the key element of such transmission. To learn the degree of toxocara invasion in domestic cats and dogs living in Moscow, we studied their feces for 7 years applying the flotation method. We found that in domestic dogs the intensity of toxocara invasion was 2.43%, but there is a big difference between puppies and adult animals: 5.53% of the former, twice as much as the latter, suffered from the invasion. The intensity of infection in adult cats was 3.97%; kittens, same as puppies, were more prone to host toxocara: 10.44% of those examined did. In general, 5.75% of cats had toxacara, which is twice as much compared to dogs; the figure applies to all ages. Stable infestation of domestic animals with this species of helminths makes them a constant source of toxocara eggs contamination in urban environments, which ups the risk of larvae toxocariasis for people.

Received: 2018-06-16

Published online: 2018-09-25

DOI: 10.24075/brsmu.2018.044

Comments 0

VIEWS 4613

Shevelev AB, Isakova EP, Trubnikova EV, La Porta N, Martens S, Medvedeva OA, Trubnikov DV, Akbaev RM, Biryukova YuK, Zylkova MV, Lebedeva AA, Smirnova MS, Deryabina YI

Due to the spreading and increasing drug resistance of pathogens, the search for novel antibiotics is becoming ever more important. Plant-derived polyphenols are a vast and promising class of compounds with a potential to fight infectious diseases. Still, they are not routinely used in clinical practice. No reports on the in vivo studies of these compounds have been presented. The aim of our work was to compare the antimicrobial activity of resveratrol (stilbene), dihydroquercetin and dihydromyricetin (flavonols) extracted from the bark and wood of conifers against the dermatophytes Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Using the radial diffusion assay, we established that dihydroquercetin, resveratrol and dihydromyricetin exhibit high activity against S. aureus even at the smallest possible concentrations of 0.22, 0.15, and 0.15 mM, respectively. In contrast, the highest achievable concentrations of these compounds in the solutions (21.5, 15.5 and 15.0 mM for dihydroquercetin, resveratrol and dihydromyricetin, respectively) have no effect on the growth of P. aeruginosa and C. albicans. These findings suggest that polyphenols derived from conifers could have a potential to be used as a medicine for topical application to treat bacterial infections of the skin caused by S. aureus.

Received: 2018-06-13

Published online: 2018-09-19

DOI: 10.24075/brsmu.2018.043

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VIEWS 5386

Rustamova YK, Imanov GG, Azizov VA

The efficacy of cardiac MRI in the diagnosis of hibernating myocardium remains understudied. The existing body of evidence on this matter comes mainly from observational studies carried out in heterogenous (in terms of cardiac pathology) cohorts of patients, which complicates the interpretation of the results. The aim of our study was to evaluate the efficacy of cardiac imaging techniques in 144 patients with a history of myocardial infarction, multivessel coronary artery disease and a low ejection fraction of the left ventricle. All participants underwent stress echocardiography and cardiac MRI examinations. The following parameters were factored into: a) the number of identified segments with abnormal myocardial contractility; b) the transmurality index (scar thickness); c) the volume of the viable myocardium relative to its total mass. The study revealed that on average there were 2.72 ± 0.82 segments with contractile dysfunction per patient. Cardiac MRI was able to detect significantly more hibernating segments than stress echocardiography. On average, the difference in the number of detected segments was 36 (56; 86) at 95% CI and р < 0.01. We established that as the transmurality index increases, the number of hypokinetic segments decreases (r = –0.78; р = 0.0314) while the number of akinetic segments (r = –0.84; р = 0.0282) goes up. This needs to be accounted for when selecting a treatment strategy for such patients. We conclude that cardiac MRI is a more effective and sensitive diagnostic technique in patients with hibernating myocardium that allows detecting significantly more cardiac segments with contractile dysfunction than stress echocardiography. Delayed contrast enhancement is instrumental in estimating the thickness and extent of cardiac fibrosis, the parameters that should be accounted for when deciding on the treatment strategy in such patients.

Received: 2018-01-16

Published online: 2018-09-17

DOI: 10.24075/brsmu.2018.042

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VIEWS 5161

Avetisova KG, Kostyuk SV, Kostyuk EV, Ershova ES, Shmarina GV, Veiko NN, Spiridonov DS, Klimenko PA, Kurtser MA

Placental pathology is accompanied by the activation of apoptosis in the trophoblast and the subsequent increase in the concentrations of microvesicles containing placental (or fetal) DNA accumulating in the maternal blood. Fragments of fetal DNA stimulate the release of nuclear and/or mitochondrial DNA fragments by neutrophils. Therefore, one can expect that complicated pregnancies will be characterized by the dramatic elevation of total cell-free DNA (cfDNA) levels in maternal plasma. The aim of this work was to study the dynamics of plasma cfDNA concentrations and the activity of DNase I, an enzyme involved in the elimination of cfDNA from the bloodstream, in nonpregnant and pregnant women. Our study recruited 40 healthy nonpregnant women, 40 women with uncomplicated pregnancies and 35 women with the intrauterine growth restriction (IUGR) of the fetus. We did not observe the elevation of the total cfDNA concentrations in the patients with complicated pregnancies. Moreover, cfDNA concentrations in their plasma were even lower (though this difference was statistically insignificant) than in healthy pregnant and nonpregnant women. The median values of cfDNA concentrations in the group of healthy nonpregnant women were 75.5 ng/ml; in the group of healthy pregnant women, 78.0 ng/ml; and in the patients with IUGR, it was 42.1 ng/ml. At the same time, we observed a significant increase in DNase I activity in the plasma of women with IUGR. The median DNase I activity in the groups of healthy pregnant and nonpregnant women was 3.0 and 3.4 IU/ml, respectively. In patients with different grades IUGR of the fetus this parameter was as high as 6.3 IU/ml (р < 0.001). Increased DNase I activity in the plasma of women with complicated pregnancies indirectly suggests a transient elevation of circulating cfDNA levels. Our study shows that the high level of activity exhibited by the cfDNA elimination system impedes the analysis of cfDNA concentrations in complicated pregnancies and skews its results. However, if cfDNA, DNase I activity and cfDNA/DNase I ratio were all taken into account, it could be possible to develop a tool for the monitoring of cell death in the mother throughout the entire pregnancy.

Received: 2018-03-15

Published online: 2018-09-15

DOI: 10.24075/brsmu.2018.041

Comments 0

VIEWS 5686

Shur KV, Umpeleva TV, Bekker OB, Maslov DA, Zaychikova MV, Vakhrusheva DV, Danilenko VN

Evolution of Mycobacterium tuberculosis have lead to the development of a number of lineages that have unique phenotypes and genotypes and are associated with certain geographical regions. Thus, compared to the reference strains of M. tuberculosis, Beijing and LAM genotypic lineages, which are the most common in the world, are highly virulent and transmissible. However, the extensive use of antibiotics over the past 50 years has caused the next evolutionary leap, which yielded new, epidemiologically dangerous sublineages: Beijing-B0 in Russia, Beijing-modern-4 in China and KZN in South Africa. This study aimed at investigating the effect the immune dysfunction predictors registered in patients have on the severity of tuberculosis (TB) developing after contracting M. tuberculosis Beijing-B0. We compiled a sample of patients with newly diagnosed TB caused by M. tuberculosis Beijing-B0, searched for the immune-suppressing diseases/conditions in their medical history and developed their immunograms. No connection was found between the state of the immune system and the characteristics of the disease we considered.

Received: 2018-06-02

Published online: 2018-08-24

DOI: 10.24075/brsmu.2018.040

Comments 0

VIEWS 5137

Maslov DA, Bekker OB, Shur KV, Vatlin AA, Korotina AV, Danilenko VN

The spread of multidrug and extensively drug-resistant Mycobacterium tuberculosis urges the development of novel antituberculosis drugs. Previously, we studied the compounds representing the class of substituted imidazo[1,2-b][1,2,4,5] tetrazines capable of inhibiting serine/threonine protein kinases (STPK) in the original M. smegmatis aphVIII+ test-system. To unveil the mechanism of action of drug candidates, it is necessary to search for mutations in the mycobacterial genome that confer resistance to these compounds. The aim of our work was to find and describe such mutations in M. smegmatis strains. We carried out the whole-genome sequencing of 9 mutants resistant to 3 imidazo[1,2-b][1,2,4,5]tetrazines. Seven of 9 mutant strains were found to have the Y52H mutation in the highly conserved mycobacterial gene MSMEG_1601 encoding a protein with an unknown function. Additionally, three of those 7 strains were shown to have two mutations in the MSMEG_1380 encoding a transcriptional regulator. The remaining 2 mutant strains had mutations in MSMEG_0641 and MSMEG_2087 genes encoding transporter-proteins. No mutations were found in STPK genes, meaning that they might be not the primary targets of the studied compounds. Further investigation of MSMEG_1601 function may be of interest as this protein might be the biological target or a part of a new mechanism underlying resistance to antituberculosis drug candidates.

Received: 2018-05-30

Published online: 2018-08-23

DOI: 10.24075/brsmu.2018.039

Comments 0

VIEWS 4724