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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Telysheva EN, Snigireva GP

Screening for cell-free DNA usually referred to as liquid biopsy holds great promise in cancer diagnosis and treatment. This article presents the results of the analysis of somatic tumor-specific mutations in circulating free DNA (cfDNA) isolated from the blood plasma of patients with stages I–IV colorectal cancer, based on the use of wild-type blocking allele-specific real-time polymerase chain reaction. This technique was specially designed for the analysis of biological specimens containing small amounts of mutant circulating tumor DNA. The study included 46 patients (18 female and 28 male participants) between 48 and 86 years of age (mean age was 67.1 ± 8.8 years). All patients underwent surgical treatment (radical surgery was performed on 85 % of the participants). Besides the molecular genetic analysis of cfDNA isolated from the blood plasma, standard histological staining was performed. Patients’ blood samples were collected before the surgery and on day 5 after it to test for KRAS and BRAF mutations. The applied PCR technique proved to be effective in detecting mutations in the RAS genes in stages II–IV of the disease, its sensitivity threshold being 0.1 %. Analysis of cfDNA before and after surgery may provide additional information on the surgical treatment outcome, development of new metastases, or presence of those previously overlooked. Wild-type blocking allele-specific real-time PCR is awaiting further validation in different clinical situations.

Received: 2017-08-08

Published online: 2017-10-29

DOI: 10.24075/brsmu.2017-04-02

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VIEWS 3333

Cell-free DNA (cfDNA) was discovered in human blood plasma as early as the middle of the 20th century, but it was not until a few decades ago that knowledge of human genome and epigenome in health and pathology became sufficient and methods of nucleic acid analysis became more advanced to encourage active research of the diagnostic potential of cfDNA. The use of cfDNA as a diagnostic biomarker is conventionally referred to as liquid biopsy. The following review tells a story of cfDNA discovery, summarizes contemporary views on cfDNA sources inside the body and touches upon possible prognostic and diagnostic applications of cfDNA analysis in medicine, specifically in cancer and prenatal screening, prediction of implant failure and sepsis development.

Received: 2017-08-25

Published online: 2017-10-29

DOI: 10.24075/brsmu.2017-04-01

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VIEWS 3983

Ryzhkin SA, Margulis AB, Kurinenko BM

Medical or occupational exposure of patients and healthcare personnel to ionizing radiation (IR) can be a cause of genetic disorders. In this article we discuss the efficiency of the following tests used to comprehensively assess the effects of ionizing radiation on the genetic apparatus of a cell: the Ames test, the micronucleus test and the FISH method. We provide examples of their use, outline their advantages and drawbacks, estimate the possibility of designing more advanced test systems and discuss requirements for their implementation.

Received: 2017-04-10

Published online: 2017-07-20

DOI: 10.24075/brsmu.2017-03-10

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VIEWS 3853

Understanding the role of the environment in the dynamics of gene-environment interactions shaping psychological traits of the child is one of the central issues of contemporary psychogenetics. The socioeconomic status of the parents (education in particular) is a critical factor regulating the share of environmental and genetic influences on the child’s cognitive abilities. This work is a study of phenotypic associations between the results of the subtests of the Heidelberg Speech Development Test designed to measure children’s speech and language competence, by computing genotypic and environmental correlations between its components. Children were divided into groups based on the educational level of their mothers (medium and high); each group was analyzed separately. For our analysis we used the twin method: the group of twins born to mothers with medium-level education included 17 monozygotic and 11 dizygotic twin pairs; the group of children born to highly educated mothers was comprised of 17 monozygotic and 22 dizygotic twin pairs. All children were aged from 7 years to 8 years and 11 months. Family report forms revealed an association between maternal education and individualized approach to the upbringing of each of the twins. It was shown that in families with highly educated mothers, differences in the upbringing strategies improve the development of language and speech competencies of the child, strengthen the relationship between various language competencies, increase the contribution of the genotype to and decrease the role of the general family environment in this relationship.

Received: 2017-04-14

Published online: 2017-07-20

DOI: 10.24075/brsmu.2017-03-09

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VIEWS 3827

Sergeenko EYu, Volovets SA, Darinskaya LYu, Zhitareva IV, Zhuravleva AI, Butorina AV, Yashinina YuA, Volkova OV

State-of-the-art rehabilitation equipment offers a wide range of static and dynamic exercise programs for fall prevention by improving balance control during standing or walking. Our study aimed to provide a rationale for the use of the BalanceTutor rehabilitation treadmill to improve static and dynamic balance in patients who had suffered an acute cerebrovascular accident. The study included 72 patients with postural balance impairments in their late recovery period. In the experimental group, center of pressure (COP) sway area and COP velocity decreased significantly, measured with patients’ eyes opened (р = 0.0476 and р = 0.0176, respectively) and closed (р = 0.0072 and р = 0.0037, respectively). At the end of the rehabilitation program, we observed a statistically significant increase in the electromyographic signal amplitude on the stroke-affected side of the body in m. peroneus longus (р = 0.0117), consistent with the regained muscle strength in the lower extremities of the affected body side measured by McPeak and Veyss 6-point scales. Tinetti gait and balance scores also improved (р = 0.0513 and р = 0.0274, respectively). Thus, the use of the BalanceTutor treadmill in the rehabilitation of poststroke patients proves to be effective and reasonable.

Received: 2017-06-22

Published online: 2017-07-20

DOI: 10.24075/brsmu.2017-03-08

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VIEWS 4284

Katkova NYu, Bodrikova OI, Sergeeva AV, Bezrukova IM, Pokusaeva KB

Preterm delivery (PD) is one of the central challenges faced by contemporary obstetrics. There has been growing evidence of the role of the innate immune response in triggering infection-associated preterm labor. Our study aimed to investigate the local immune status of women in different PD scenarios. The study enrolled 77 pregnant women; 25 of them constituted the control group (delivery at term). The experimental group was divided into two subgroups based on the PD type: Subgroup 1A included 28 women with spontaneous premature rupture of membranes in the absence of active labor, and Subgroup 1B included 24 women who went into genuine preterm labor. Cervical scrape specimens were collected from all patients to determine the level of expression of the following innate immunity genes: IL1B, IL10, IL18, TNFa, TLR4, GATA3, CD68, and B2M. The tests were performed using the ImmunoQuantex assay by DNA-Technology, Russia. Compared to the genuinely preterm women from Subgroup 1B and the controls, the women with premature rupture of membranes demonstrated statistically significant reduction in the expression of TLR4 and GATA3 and a higher inflammatory index (Me = 99.5 %, p < 0.01). No significant differences in these parameters were observed between Subgroup 1B and the controls. The revealed differences in the local immunity profiles of women indicate that pathways leading to the scenarios of premature labor studied in this work are not the same.

Received: 2017-04-10

Published online: 2017-07-19

DOI: 10.24075/brsmu.2017-03-07

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VIEWS 3842

Borisevich DI, Krasnenko AYu, Stetsenko IF, Plakhina DA, Ilinsky VV

Today, next generation sequencing (NGS) is extensively used in the research setting. However, high costs of NGS testing still prevent its routine use in clinical practice. One of the factors affecting the cost of sequencing is the number of reads per site, i.e. the number of times each nucleotide gets sequenced. On the one hand, lower coverage makes the whole process much faster and less time-consuming. On the other hand, it results in poor data quality. No unanimous opinion has been reached yet as to what minimum depth of coverage can produce reliable results. The aim of this study was to determine the minimum number of reads sufficient for accurate base calling of heterozygous and single nucleotide variants (SNV). Using bioinformatics methods, we demonstrate that accuracy can be achieved at a minimum depth of 12x.

Received: 2017-06-22

Published online: 2017-07-19

DOI: 10.24075/brsmu.2017-03-06

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VIEWS 3859

Chicherin IV, Levitskii SA, Krasheninnikov IA, Tarassov I, Kamenski P

Mitochondrial DNA mutations cause severe inherited disorders in humans. To date, there are a few therapeutic strategies for their correction; however, it is highly unlikely that they would be routinely used in clinical practice. The past few years have witnessed the rapid progress of a genome editing technology known as CRISPR/Cas9. The present review focuses on the current strategies to combat mitochondrial mutations and reveals their major drawbacks. The article also explores the possibility of creating a possible specific CRISPR/Cas9 tool for correcting mitochondrial DNA mutations and provides a rough description of its mechanism of action. A particular focus is paid to technical challenges. On the whole, we see no principal barriers to implementing a mitoCRISPR/Cas9 system for treating mitochondrial disorders.

Received: 2017-06-20

Published online: 2017-07-19

DOI: 10.24075/brsmu.2017-03-05

Comments 0

VIEWS 4413