[The levels of certain circulating microRNAs in hypertrophic cardiomyopathy are associated with echocardiographic parameters].

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease; it is characterized by left ventricular (LV) hypertrophy that cannot be explained by hemodynamic causes. It is believed that sarcomere dysfunction underlies the pathogenesis of this disease, however, only half of patients with the HCM phenotype have mutations in sarcomere-encoding genes. HCM is distinguished by both high genetic and clinical heterogeneity and therefore more studies are seeking to investigate a regulation of gene expression in HCM and how the abnormalities in this process can affect disease phenotype. One of the levels of regulation of gene expression - a post-transcriptional level - is mediated by short non-coding microRNAs that inhibit protein synthesis. AIM: To identify the correlations between levels of circulating microRNAs, previously shown to be associated with HCM, and clinical parameters of HCM patients. MATERIALS AND METHODS: Correlation analysis of miR-499a-5p, miR-454 and miR-339-5p plasma levels and clinical parameters of 33 HCM patients, examined from 2019 to 2021, has been performed. RESULTS: Variants in HCM-associated genes were found in 49% of patients. There were no clinical differences between genotype-positive and genotype-negative patients. MiR-499a-5p level correlated with LV ejection fraction, miR-454 level - with LV diastolic function parameters and miR-339-5p level - with left atrium dimension. CONCLUSION: Levels of certain circulating microRNAs correlate with echocardiographic parameters in HCM patients.

[DNA Methylation Profile of CD14+ Monocytes Changes in Primary Progressive Multiple Sclerosis].

Multiple sclerosis (MS) is a chronic autoimmune inflammatory and neurodegenerative disease of the central nervous system, which is characterized by significant clinical heterogeneity. Primary progressive MS (PPMS) develops in 10-15% of patients. Unlike the most common relapsing-remitting form of MS, PPMS involves steady progress of neurodegeneration and, as a consequence, a persistent gradual increase in neurological symptoms. The peculiarities of epigenetic regulation of gene expression may be one of the reasons for the differences in the pathogenesis of the two MS forms. DNA methylation is one of the key epigenetic mechanisms, which remains almost unexplored in different cell populations of PPMS patients. The goal of this work was to identify differential methylation profiles of the CpG sites in the CD14+ monocyte DNA, which characterize PPMS. A genome-wide analysis of DNA methylation in PPMS patients and healthy individuals has identified 169 differentially methylated positions (DMPs), 90.5% of which were hypermethylated in PPMS patients. More than half of all DMPs are located in/near known genes and within CpG islands and their neighboring regions, which indicates their high functional significance. We have found six differentially methylated regions (DMRs) in the OR2L13, CAT, LCLAT1, HOXA5, RNF39, and CRTAC1 genes involved in inflammation and neurodegeneration, which indicates active epigenetic regulation of their expression.

Delay-differential SEIR modeling for improved modelling of infection dynamics.

SEIR (Susceptible-Exposed-Infected-Recovered) approach is a classic modeling method that is frequently used to study infectious diseases. However, in the vast majority of such models transitions from one population group to another are described using the mass-action law. That causes inability to reproduce observable dynamics of an infection such as the incubation period or progression of the disease's symptoms. In this paper, we propose a new approach to simulate the epidemic dynamics based on a system of differential equations with time delays and instant transitions to approximate durations of transition processes more correctly and make model parameters more clear. The suggested approach can be applied not only to Covid-19 but also to the study of other infectious diseases. We utilized it in the development of the delay-based model of the COVID-19 pandemic in Germany and France. The model takes into account testing of different population groups, symptoms progression from mild to critical, vaccination, duration of protective immunity and new virus strains. The stringency index was used as a generalized characteristic of the non-pharmaceutical government interventions in corresponding countries to contain the virus spread. The parameter identifiability analysis demonstrated that the presented modeling approach enables to significantly reduce the number of parameters and make them more identifiable. Both models are publicly available.

[A comparison of DNA methylation profiles of blood mononuclear cells in patients with multiple sclerosis in remission and relapse]. / Sravnenie profilei metilirovaniya DNK mononuklearnykh kletok krovi bol'nykh rasseyannym sklerozom v stadiyakh remissii i obostreniya.

OBJECTIVE: To study the whole-genome DNA methylation profiles of peripheral blood mononuclear blood cells (PBMCs) of patients with relapsing-remitting multiple sclerosis (RRMS) in remission and relapse in order to assess the contribution of this epigenetic mechanism of gene expression regulation to the activity of the pathological process. MATERIAL AND METHODS: Eight patients with RRMS in remission and 6 patients in relapse were included in the study. Methylation levels of DNA CpG sites in PBMCs were analyzed using Infinium HumanMethylation450 BeadChip DNA microarrays. RESULTS: Seven differentially methylated positions (DMPs) were identified, of which 3 were hypermethylated (cg02981003, cg18486102, cg19533582) and 4 were hypomethylated (cg16814680, cg1964802, cg18584440, cg08291996) during RRMS relapse. Five DMPs are located in protein-coding genes (GPR123, FAIM2, BTNL2, ZNF8, ASAP2), one in microRNA gene (MIR548N), and one in an intergenic region. For all identified DMPs, we observed a change in DNA methylation levels of more than 20% (range 20.2-57.5%). Hierarchical clustering of DNA samples on the heatmap shows their clear aggregation into separate clusters corresponding to RRMS patients in the stages of relapse and remission. CONCLUSION: For the first time it was shown that during relapse and remission of RRMS there are differences in the DNA methylation profile that allow discrimination between these clinical stages. These data indicate the involvement of the epigenetic mechanism of DNA methylation in the activation of the pathological process in RRMS.

[Genome-Wide Analysis of DNA Methylation in Cd4+ T Lymphocytes of Patients with Primary Progressive Multiple Sclerosis Indicates Involvement of This Epigenetic Process in the Disease Immunopathogenesis].

The pathogenesis of multiple sclerosis (MS), a chronic disease of the CNS, includes autoimmune and neurodegenerative components. In most cases, patients develop relapsing-remitting MS (RRMS), while 10-15% of patients develop primary progressive MS (PPMS), which differs from RRMS in the mechanisms of the pathological process, some demographic, and some clinical characteristics. These differences may be explained by the epigenetic regulation of gene expression in PPMS including DNA methylation as one of the key epigenetic processes. The features of DNA methylation in various cell populations in PPMS patients remain understudied. The goal of this study is to identify differentially methylated CpG sites (DMSs) of the genome of CD4+ T lymphocytes, which characterize PPMS. The study included eight treatment-naive PPMS patients and eight healthy controls. Genome-wide analysis of DNA methylation of CD4+ T lymphocytes was performed using high-density DNA microarrays. We have identified 108 DMSs, which distinguish PPMS patients from healthy controls. In PPMS patients 81% of the DMSs are hypermethylated. More than a half of the identified DMSs are located in known genes in CpG islands and adjacent regions, which indicates a high functional significance of these DMSs in PPMS development. Analysis of the overrepresentation of DMS-containing genes in the main biological processes demonstrates their involvement in the regulation of cell adhesion to the extracellular matrix and the development of the immune response, i.e., antigen processing and presentation, and development of the immune system. Genome-wide analysis of DNA methylation in CD4+ T lymphocytes of PPMS patients indicates the involvement of this epigenetic process in the immunopathogenesis of the disease. These results may help better understand the pathogenesis of this severe form of MS.

[MiRNA miR-375 as a Multifunctional Regulator of the Cardiovascular System].

MicroRNA (miRNA) miR-375 acts as a multifunctional regulator of the activity of many physiological and pathological cellular processes by interacting with a large number of target genes. MiR-375 is involved in the regulation of the differentiation and functioning of cells of the nervous and immune systems, bone and adipose tissue, and even the life cycle of a number of viruses. Changes in miR-375 expression have been found in carcinogenesis, inflammation, and autoimmune and cardiovascular diseases. Every year, new studies appear that expand our understanding of the range of processes regulated by this miRNA. According to the latest data, miR-375 can be used as a biomarker and therapeutic target in some diseases. This review discusses the role of miR-375 in the functioning of the cardiovascular system in health and disease.

[Risk of Multiple Sclerosis: Analysis of Interactions Between Variants of Nuclear and Mitochondrial Genomes].

There is increasing evidence that the interaction of the mitochondrial and nuclear genomes substantially affects the risk of neurodegenerative diseases. The role of mitonuclear interactions in the development of multiple sclerosis, a severe chronic neurodegenerative disease of a polygenic nature, is poorly understood. In this work, we analyzed the association of multiple sclerosis with two-component mitonuclear combinations that include each of seven polymorphic variants of the nuclear genome localized in the region of the UCP2, and KIF1B genes and in the PVT1 locus (MYC, PVT1, and MIR1208 genes) and each often polymorphisms of the mitochondrial genome, as well as individual genetic variants that make up these combinations. Association of the individual components of these combinations with multiple sclerosis was also evaluated. 507 patients with multiple sclerosis and 321 healthy individuals were enrolled in the study, all participants were ethnic Russians. Two mitonuclear combinations associated with multiple sclerosis were identified: the UCP2 (rs660339)*A + MT-ATP6 (rs193303045)*G combination was characterized by p-value = 0.015 and OR= 1.39 [95% CI 1.05-1.87], and the PVT1 (rs2114358)*G + MT-ND1 (rs1599988)*С combination - by p-value = 0.012 and OR = 1.77 [95% CI 1.10-2.84]. Only one of the individual components of these combinations, allele rs660339*A of the nuclear gene UCP2 encoding uncoupling protein 2 of the mitochondrial anion carrier family, was independently associated with multiple sclerosis (p = 0.028; OR = 1.36 [95% CI 1.01-1.84]). This study expands the current understanding of the role of mitonuclear interactions and variance of nuclear genes, whose products function in mitochondria, and in risk of MS.

DNA Methylation As an Epigenetic Mechanism in the Development of Multiple Sclerosis.

The epigenetic mechanisms of gene expression regulation are a group of the key cellular and molecular pathways that lead to inherited alterations in genes' activity without changing their coding sequence. DNA methylation at the C5 position of cytosine in CpG dinucleotides is amongst the central epigenetic mechanisms. Currently, the number of studies that are devoted to the identification of methylation patterns specific to multiple sclerosis (MS), a severe chronic autoimmune disease of the central nervous system, is on a rapid rise. However, the issue of the contribution of DNA methylation to the development of the different clinical phenotypes of this highly heterogeneous disease has only begun to attract the attention of researchers. This review summarizes the data on the molecular mechanisms underlying DNA methylation and the MS risk factors that can affect the DNA methylation profile and, thereby, modulate the expression of the genes involved in the disease's pathogenesis. The focus of our attention is centered on the analysis of the published data on the differential methylation of DNA from various biological samples of MS patients obtained using both the candidate gene approach and high-throughput methods.

[Hypertrophic Cardiomyopathy as an Oligogenic Disease: Transcriptomic Arguments].

Hypertrophic cardiomyopathy (HCM) is the most common genetically determined heart pathology and is often accompanied by fatal complications. Today, the traditional view of the monogenic origin of HCM is being replaced by the idea of it as an oligogenic disease, the clinical phenotype of which is determined not only by mutations in the genes encoding sarcomere proteins in cardiomyocytes, but also by the contribution of other genes (other sarcomeric genes, non-sarcomeric protein-coding modifier genes, and regulatory non-coding RNA genes). Transcriptome analysis is an informative approach for elucidating the nature of HCM, which allows one to evaluate the expression of all genes, evaluate the effect of mutations in a gene on its transcript level, and reveal the mechanisms involved in the regulation of gene expression. This review presents an analysis of published data on the spectra of genes whose differential expression has been detected in the myocardium during the development of HCM in humans and model animals. Special attention is paid to the genes of non-coding regulatory RNAs: miRNAs and long non-coding RNAs, which may be involved in the pathogenesis of the disease. We analyzed studies devoted to the investigation of miRNA levels in the blood of HCM patients to explore the available diagnostic and prognostic biomarkers of the disease. The totality of the reviewed data, despite their relative scarcity, indicates the effectiveness of transcriptome profiling in studying the molecular mechanisms of HCM pathogenesis.

[Variability of the Mitochondrial Genome and Development of the Primary Progressing form of Multiple Sclerosis].

Recently, it has been shown that dysfunction of mitochondria is an important component of the molecular mechanisms of the development of many neurodegenerative diseases. These include multiple sclerosis, a chronic autoimmune and neurodegenerative disease of the central nervous system, which is characterized by clinical heterogeneity. The role of genetic variability of mitochondrial DNA in the development of various clinical forms of multiple sclerosis is poorly understood. The aim of present study was to analyze the association often mitochondrial DNA single nucleotide polymorphisms and the nine most common European mitochondrial haplogroups (H, J, K, U, T, I, V, W and X) with a severe and relatively rare multiple sclerosis disease form-primary progressive multiple sclerosis. 110 patients with primary progressive multiple sclerosis and 406 healthy controls were enrolled in the study, all ethnic Russians. For the first time association of the m.12308*G (rs2853498) variant (P = 0.024) and haplogroup U (P = 0.0004, passes the adjustment for multiple comparisons: Pcorr = 0.0076) with primary progressive multiple sclerosis was shown. Comparison of these data with the results of our previous study [1], that was focused on the role of mitochondrial genome variability in susceptibility to the most common form of multiple sclerosis, relapsing-remitting multiple sclerosis, leads to the conclusion that two different mitochondrial haplogroups, U and J, are involved in the development of two different clinical forms of multiple sclerosis. The results may contribute to the identification of new targets for the treatment of primary progressive multiple sclerosis, for which there is no effective pathogenetic treatment at the moment.

[Age-Dependent Approach to Search for Genetic Variants Associated with Myocardial Infarction].

Myocardial infarction (MI), one of the most common manifestations of cardiovascular system aging, is often fatal. The vast majority of studies on genetic susceptibility to age-dependent diseases are carried out using the case-control study design. However, its use involves a number of difficulties, most of which arise when establishing the control group of relatively healthy individuals. In this work, survival functions were analyzed for carriers of alternative polymorphic variants of 18 genes that had been tested for association with MI using the case-control approach in our previous study, and the magnitude of the shift in the age of the disease onset depending on individual variations of the genome was estimated. The following risk variants were associated with the age of MI: rs2430561*A of IFNG (HR = 1.3, P = 0.043), rs1799889*5 of PAI-1 (HR = 1.3, P = 0.039), rs1800896*GG of IL10 (HR = 1.5, P = 0.0048), rs1800471*C of TGFB1 (HR = 1.5, P = 0.043), and rs11614913*TT of MIR196A2 (HR = 1.5, P = 0.035). In carriers of these variants, the disease developed 3-6 years earlier than in carriers of alternative variants. The results of this study were compared with data on the associations with MI previously obtained on the same sample using the case-control approach. It turned out that the estimates based on the two methods mostly disagreed. However, the age-dependent approach relies on fewer assumptions that can be additionally verified. In our opinion, it makes this approach more promising than the case-control design.

Loading Rate of Exogenous and Autoantigenic Determinants on Major Histocompatibility Complex Class II Mediates Resistance to Multiple Sclerosis.

Genetic analysis of thousands of patients with multiple sclerosis (MS) and healthy Russian donors showed that the carriage of groups of HLA-DRB1*15 and HLA-DRB1*03 alleles is associated with the risk of MS, whereas the carriage of groups of HLA-DRB1*01 and HLA-DRB1*11 alleles is protective. Recombinant HLA-DRB1*01:01 with a high affinity can recognize the fragments of myelin basic protein (MBP), one of the autoantigens in MS. However, the comparison of the kinetic parameters of the load of MBP and viral HA peptides on HLA-DRB1*01:01, which is catalyzed by HLA-DM, showed a significantly lower rate of exchange of CLIP for MBP peptides. We assume that the observed protective properties of the group of HLA-DRB1*01 alleles may be directly associated with the ability of HLA-DRB1*01:01 to kinetically distinguish peptides of exogenous and endogenous nature.

[Variability of the MIR196A2 Gene as a Risk Factor in Primary-Progressive Multiple Sclerosis Development].

Multiple sclerosis is a chronic disease of the central nervous system, combining in its pathogenesis both autoimmune and neurodegenerative components, and is characterized by a highly heterogeneous clinical phenotype. Genetic susceptibility to the development of the most common relapsing-remitting course of the disease is extensively studied, while the genetic architecture of the aggressive primary progressive course of multiple sclerosis remains poorly understood. We analyzed the association of polymorphic variants in miRNA genes MIR146A, MIR196A2, and MIR499A with the risk of primary progressive multiple sclerosis one by one and in biallelic combinations with variants of immune-related genes; the analysis was performed in comparison with healthy individuals and with relapsing-remitting multiple sclerosis patients. The allele MIR196A2*C was useful in discriminating between two main courses of multiple sclerosis, one by one and in combination with alleles of the IFNAR2, IL7RA, IL6, PVT1, CD86, CCL5, and PSMB9 genes. The data presented in the current work may be used for the construction of a biomarker panel, to differentiate primary progressive and relapsing-remitting courses of multiple sclerosis on the initial stages of the disease.

The Contribution of Major Histocompatibility Complex Class II Genes to an Association with Autoimmune Diseases.

Genetic studies of patients with autoimmune diseases have shown that one of the most important roles in the developing of these diseases is played by a cluster of genes of the major histocompatibility complex (MHC), as compared with other genome areas. Information on the specific contribution of MHC alleles, mostly MHC class II ones, to the genetic predisposition to autoimmune diseases is crucial for understanding their pathogenesis. This review dwells on the most relevant aspects of this problem: namely, the correlation between carriage of certain MHC II alleles and an increased (positively associated allele) or reduced (negatively associated allele) probability of developing the most common autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, autoimmune thyroiditis, etc. The most universal haplotypes, DR3-DQ2 and DR4-DQ8, are positively associated with many of these diseases, while the universal allele HLA-DRB1*0701 is protective.

Variants of Mitochondrial Genome and Risk of Multiple Sclerosis Development in Russians.

For the first time in the history of ethnic Russians, an association analysis the development of multiple sclerosis (MS) was performed for the mitochondrial haplogroups H, J, K, and U, as well as for the individual mitochondrial DNA (mtDNA) polymorphisms discriminating these haplogroups (m.1719G > A, m. 7028C > T, m.9055G > A, m.10398A > G, m.12308A > G). A total of 283 unrelated patients with the relapsing-remitting form of MS and 290 healthy controls were enrolled in the study. Association of haplogroup J with MS was observed (P = 0.0055, OR = 2.00 [95% CI 1.21-3.41]). After gender stratification, the association remained significant in women (P = 0.0083, OR = 2.20 [95% CI 1.19-4.03]). A multilocus analysis of the association between combinations of mtDNA haplogroups with variants of 38 nuclear immune-related genes and MS risk was carried out. MS-associated biallelic combinations of haplogroup J with the alleles CCL5 rs2107538*A, PVT1 rs2114358*G, TNFSF14 rs1077667*C, and IL4 rs2243250*C, which were not associated with MS individually, were identified. For the combination of haplogroup J and the CCL5*A allele (P = 0.00043, OR = 5.47 [95% CI 1.85-16.15]), a epistatic (synergistic) interaction between the components was established using two statistical criteria: the PFLINT value in the Fisher-like interaction numeric test and the synergy factor, SF (PFLINT = 0.025, SF = 4.32 [95% CI 1.20-15.60]). The combination of haplogroup J and the PVT1*G allele is characterized by PFLINT = 0.084; SF = 3.05 [95% CI 1.00-9.31] and can also be epistatic. Thus, interaction between nuclear and mitochondrial genome components in the risk of developing MS was demonstrated for the first time.

[Polymorphic variants of the immune response genes as risk factors for primary progressive multiple sclerosis]. / Polimorfnye varianty genov immunnogo otveta kak faktory riska razvitiia pervichno-progressiruiushchego rasseiannogo skleroza.

AIM: To analyze the involvement of immune response genes in the pathogenesis of primary progressive multiple sclerosis (PPMS). MATERIAL AND METHODS: This multicenter study included 111 patients with PPMS from the Russian ethnic group. The association of PPMS with genes of immune system was analyzed by the study of polymorphic variants of genes of cytokines and genes of antigen-presenting cells. RESULTS AND CONCLUSION: The genotypes of IL-4 (rs2243250)*C/C and CLEC16A (rs6498169)*G/G were associated with PPMS in Russians. The association between the HLA-DRB1*15 and PPMS found out in other populations was confirmed in Russians.

Whole-Genome DNA Methylation Analysis of Peripheral Blood Mononuclear Cells in Multiple Sclerosis Patients with Different Disease Courses.

Multiple sclerosis (MS) is a severe neurodegenerative disease of polygenic etiology affecting the central nervous system. In addition to genetic factors, epigenetic mechanisms, primarily DNA methylation, which regulate gene expression, play an important role in MS development and progression. In this study, we have performed the first whole-genome DNA methylation profiling of peripheral blood mononuclear cells in relapsing-remitting MS (RRMS) and primary-progressive MS (PPMS) patients and compared them to those of healthy individuals in order to identify the differentially methylated CpG-sites (DMSs) associated with these common clinical disease courses. In addition, we have performed a pairwise comparison of DNA methylation profiles in RRMS and PPMS patients. All three pairwise comparisons showed significant differences in methylation profiles. Hierarchical clustering of the identified DMS methylation levels and principal component analysis for data visualization demonstrated a clearly defined aggregation of DNA samples of the compared groups into separate clusters. Compared with the control, more DMSs were identified in PPMS patients than in RRMS patients (67 and 30, respectively). More than half of DMSs are located in genes, exceeding the expected number for random distribution of DMSs between probes. RRMS patients mostly have hypomethylated DMSs, while in PPMS patients DMSs are mostly hypermethylated. CpG-islands and CpG-shores contain 60% of DMSs, identified by pairwise comparison of RRMS and control groups, and 79% of those identified by pairwise comparison of PPMS and control groups. Pairwise comparison of patients with two clinical MS courses revealed 51 DMSs, 82% of which are hypermethylated in PPMS. Overall, it was demonstrated that there are more changes in the DNA methylation profiles in PPMS than in RRMS. The data confirm the role of DNA methylation in MS development. We have shown, for the first time, that DNA methylation as an epigenetic mechanism is involved in the formation of two distinct clinical courses of MS: namely, RRMS and PPMS.

[Specific features of gastroesophageal reflux disease associated with obesity and overweight].

AIM: To reveal the specific features of gastroesophageal reflux disease (GERD) associated with obesity and overweight, by investigating the clinical and endoscopic manifestations of the disease, 24-hour pH-metry scores, and leptin levels. SUBJECTS AND METHODS: A total of 131 patients with GERD were examined. The data about complaints and those from life and medical histories were collected; anthropometric measurements and the results of blood biochemical tests, esophagoduodenoscopy (EPDS), and pH-metry were assessed; and the serum levels of leptin and its receptor were estimated. The patients were allocated into a study group (104 obese and/or overweight patients) and a comparison one (27 normal weight people). RESULTS: Waist circumference, hip circumference, and blood glucose levels proved to be statistically significantly higher in the study group (p<0.00000, p<0.00002, and p<0.02, respectively). The obese patients were found to have a statistically significantly higher level of leptin and a lower level of its soluble receptors: the median leptin levels were 30.42 (13.42-45.62) ng/ml in the study group and 5.47 (3.35-7.68) ng/ml in the comparison group; the median levels of the receptors were 18.83 (14.98-25.11) ng/ml and 30.93 (24.68-33.53) ng/ml, respectively). This group showed a moderate negative correlation between these indicators (rs=-0.451; p<0.0004). The study group displayed higher pH values in the gastric cardia and body (p<0.05 and p<0.04, respectively). The mucosal contact time with the refluxate having with a low pH value (<4) in the above segments turned out to be longer in the comparison group (p<0.05). There were weight-independent relationships of the leptin level to its spread, aggressiveness quotient, to the highest pH value in the gastric cardia and body, and to the mucosal contact time with the refluxate having a pH below 4.0 (rs=0.543; p<0.006; rs=0.432; p<0.04; rs=0.431; p<0.04; rs=-0.450; p<0.03, respectively), leptin receptors with a pH ratio in the gastric cardia and body, to the number of reflux episodes longer than 5 minutes in the esophagus, and to the De Meester index for this indicator (rs=0.471; p<0.04; rs=-0.455; p<0.04; rs=-0,454; p<0.04, respectively). CONCLUSION: Obese and overweight patients develop GERD in the presence of leptin resistance and biliary tract disease, which determines the specific features of the disease (alkaline or mixed refluxate) and the need for individualized therapy.

NEW DIRECTIONS FOR IMPROVEMENT OF BREAST CANCER SCREENING.

Objective: to improve breast cancer diagnosis using an independent mammographic teleassessment by two radiologists. Material and methods. The results of a dual independent assessment of 3440 X-ray mammographic examinations were analyzed. The first assessment was made by a radiologist from a therapeutic-and-prophylactic establishment who had less than one year of practical experience in a mammography screening room. The second assessment was carried out by a radiologist with more than 5 years of experience from a specialized cancer institution. Results. According to the developed specialized interpretation software, recommendations and statistics for mammographic breast cancer screening, the investigators identified a group of 31 women who were recommended to be additionally examined at an oncology dispensary to verify the diagnosis of breast cancer. Eight of 17 (47%) women with morphologically confirmed cancers after dual assessments of X-ray mammographs were called again and referred to the oncology dispensary. Conclusion. Dual independent assessment of X-ray mammographs improved the diagnosis of BC with a maximum size of 1.5 cm or less, as well as that of malignant tumors manifesting as microcalcifications or imitating a benign process.

Potassium polytitanate gas-sensor study by impedance spectroscopy.

Nanocrystalline potassium polytitanates K2O·nTiO2·mH2O represent a new type of semiconducting compounds which are characterized by a high specific surface that makes them promising for use in gas sensors. In this work, we have studied potassium polytitanate mesoporous nanoparticle agglomerates placed over a SiO2/Si substrate equipped with multiple coplanar electrodes to measure the electrical response to various organic vapors, 1000 ppm of concentration, mixed with air by impedance spectrometry in range of the 10(-2)-10(6) Hz. The recorded impedance data for each sensor segment are associated with RC components of an equivalent circuit which are applied to selectively recognize the test vapors exploiting a "multisensor array" approach.