Endogenous Regeneration of Alveolar Bone by Decellularized Tooth Matrix

The efficiency of bone tissue regeneration by decellularized tooth matrix, demineralized tooth matrix, and commercial xenograft Bio-Oss Spongiosa was compared on the model of a critical-size circular defect in the alveolar bone of the upper jaw of adult Wistar rats. The defect healing dynamics was assessed using histological, histomorphometrical, and immunohistochemical methods on days 30 and 60. In contrast to demineralized matrix and commercial xenograft, decellularized matrix induces the formation of the new bone tissue by day 60. Decellularized matrix can be considered as a biomaterial for cell-free tissue engineering for alveolar bone restoration in dentistry and maxillofacial surgery.

Identification of Chimeric NTRK3 Genes in Papillary Thyroid Cancer Cells by Analyzing the Imbalance of the Expression of 5' and 3' mRNA Fragments

The standard for detecting chimeric genes of neurotrophic receptor tyrosine kinases (NTRK) is next generation sequencing (NGS). However, this analysis is expensive and takes several days. As a rapid screening method for the detection of NTRK3-dependent papillary thyroid cancer, an analysis of the expression imbalance between 5' and 3' NTRK3 mRNA fragments was used (5'/3' RT-PCR). The reference method for detection of NTRK3 rearrangements was fluorescent in situ hybridization (FISH), and the most frequent rearrangements in papillary thyroid cancer were tested using reverse transcription PCR (RT-PCR). Using 5'/3' RT-PCR, 18 samples of papillary thyroid cancer carrying chimeric transcripts of NTRK3 mRNA were detected. The sensitivity of the developed technique was 88.9% and specificity was 99.3%. Thus, a fast and cost-effective method of screening samples of papillary thyroid cancer in paraffin blocks is proposed with acceptable sensitivity and specificity.

Differences in Transcriptomic Profiles of Brain and Thyroid Tumors with NTRK Gene Rearrangement

For tumors with chimeric NTRK genes, entrectinib and larotrectinib can be prescribed regardless of tumor localization. We compared changes in the transcriptional activity of genes in brain tumors (BT) and thyroid cancer (TC) with rearrangement (NTRK+) and without rearrangement (NTRK-) of the NTRK genes using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. We revealed an increase in the transcription of the JUN gene in NTRK+ samples in comparison with NTRK- samples: by 1.6 times for BT (p=0.239) and by 2.5 times for TC (p=0.003). The transcription of eight HOX genes in NTRK+ BT samples was also increased (by 85-725 times, p<0.05) in comparison with NTRK-. In NTRK+ TC samples, the level of miR-31 and miR-542 was statistically significantly higher (by 3 and 2.5 times, respectively) than in NTRK-samples. For the NTRK+ BT samples, the levels of miR-10b, miR-182, and miR-21 more than 5-fold surpassed the corresponding values in NTRK-samples (p<0.05). These findings reflect differences in activation of gene transcription resulting from NTRK gene rearrangement in BT and TC.

Histological Variants of Papillary Thyroid Cancer in Relation to Clinical and Morphological Parameters and Prognosis

The correlation of histological features of papillary thyroid cancer with clinical and morphological prognostic factors and cause-specific mortality was analyzed in a case-control study within a cohort of patients from the Altai Regional Oncology Center (25 cases with lethal outcome and 64 follow-up controls). Significant variability was revealed in the histological structure of papillary thyroid cancer with the prevalence of classic (62%) and less frequent follicular (19%), tall cell (8%), and solid (7%) variants. In comparison with the classic variant, the solid variant was more often associated with male sex and large tumor size; follicular and tall cell variant was associated with more frequent metastases to regional lymph nodes; follicular and solid variants were associated with an increased proportion of cases with disease stages III-IV. The main differences reflecting the effect of histological factor on the disease outcome were associated with the solid variant of papillary thyroid cancer that was detected in 21% of lethal cases and only in 2% of control subjects. The detection of this variant can be of importance as an additional prognostic factor of the postoperative survival in papillary thyroid cancer.

DNA Damage in Splenocytes of Mice Exposed to Secondary Radiation Created by 650 MeV Protons Bombarding a Concrete Shielding Barrier

The proportion of splenocytes with a high level of DNA double-strand breaks was determined in mice exposed to primary and secondary radiation created by bombarding of a concrete barrier (thickness 20, 40, and 80 cm) by 650 MeV protons. The proportion of splenocytes with a high level of DNA double-strand breaks was assessed by flow cytometric analysis of γH2AX⁺ and TUNEL⁺ cells. It is shown that concrete barrier can significantly reduce primary proton radiation; the severity of negative biological effects in mice irradiated in the center of the proton beam decreased with increasing the thickness of this barrier. However, the spectrum of secondary radiation changes significantly with increasing the barrier thickness from 20 to 80 cm and the distance from central axis of the beam from 0 to 20 cm, and the proportion of the neutron component increases, which also causes negative biological effects manifesting in a significant (p<0.05) increase in the percentage of splenocytes with a high level of DNA damage in mice irradiated at a distance of 20 cm from the center of the proton beam and receiving relatively low doses (0.10-0.17 Gy).

Solidification of ternary melts with a two-phase layer

This review is concerned with the nonstationary solidification of three-component systems in the presence of two moving phase transition regions-the main (primary) and cotectic layers. A non-linear moving boundary problem has been developed and its analytical solutions have been defined. Namely, the temperature and impurity concentration distributions were determined, the solid phase fractions in the phase transition regions and the laws of motion of their boundaries were found. It was shown that variations in the initial impurity concentration affect significantly the ratio between the lengths of the two-phase layers. A non-linear liquidus surface equation is theoretically taken into account as well.

Prediction of EVT6-NTRK3-Dependent Papillary Thyroid Cancer Using Minor Expression Profile

Solid tumors resulting from oncogenic stimulation of neurotrophin receptors (TRK) by chimeric proteins are a group of rare tumors of various localization that respond to therapy with targeted drugs entrectinib and larotrectinib. The standard method for detecting chimeric TRK genes in tumor samples today is considered to be next generation sequencing with the determination of the prime structure of the chimeric transcripts. We hypothesized that expression of the chimeric tyrosine kinase proteins in tumors can determine the specific transcriptomic profile of tumor cells. We detected differentially expressed genes allowing distinguishing between TRK-dependent tumors papillary thyroid cancer (TC) from other molecular variants of tumors of this type. Using PCR with reverse transcription (RT-PCR), we identified 7 samples of papillary TC carrying a EVT6-NTRK3 rearrangement (7/215, 3.26%). Using machine learning and the data extracted from TCGA, we developed of a recognition function for predicting the presence of rearrangement in NTRK genes based on the expression of 10 key genes: AUTS2, DTNA, ERBB4, HDAC1, IGF1, KDR, NTRK1, PASK, PPP2R5B, and PRSS1. The recognition function was used to analyze the expression data of the above genes in 7 TRK-dependent and 10 TRK-independent thyroid tumors obtained by RT-PCR. On the test samples from TCGA, the sensitivity was 72.7%, the specificity - 99.6%. On our independent validation samples tested by RT-PCR, sensitivity was 100%, specificity - 70%. We proposed an mRNA profile of ten genes that can classify TC in relation to the presence of driver NTRK-chimeric TRK genes with acceptable sensitivity and specificity.

[Is there a claudin-low phenotype of breast cancer?]

The novel molecular subtype of breast cancer (BC), named "claudin-low", was described in 2007. It was characterized by the consistently low expression of genes involved in the formation of epithelial tight junctions in combination with the high activation of genes associated with the epithelial-to-mesenchymal transition, as well as tumor stem cell markers. The similar claudin- low subtype was later identified at the transcriptional level in bladder cancer, gastric cancer, and serous ovarian cancer. However, only in relation to BC, attempts were made to create a surrogate panel for immunohistochemical identification of this subtype in a manner like the intrinsic molecular BC subtypes identified using three main markers, such as ER, PR, and HER-2. At the same time, the ambiguity in the expression of claudins among the subtypes of BC, which is defined by various authors at the immunohistochemical level, as well as the absence of both the confirmed set of immunohistochemical criteria and a unified approach to their assessment, complicate these efforts. The purpose of the review is to show that the immunohistochemical identification of claudin-low subtype of BC is a separate problem that has significant limitations, needs standardization and has not yet reached diagnostic value.

[Epithelial-stromal interactions in pancreatic adenocarcinoma: the role of stroma in disease progression]

Pancreatic ductal adenocarcinoma (PDAC) is the most common and difficult to treat form of pancreas cancer. PDAC and other solid cancers contain both tumor cells and normal connective tissue cells called stromal cells, which are responsible for the excess production of extracellular matrix. It is known that in more than 90% of PDAC tumors and in many other types of cancer, mutations of the KRAS gene are observed, the reciprocal signaling of which has been shown between tumor and stromal cells in vitro. Pancreatic stromal stellate cells are considered precursors of activated or tumor-associated fibroblasts (CAFs), which are an increasing population of cells that proliferate in situ or are recruited into the tumor. CAFs are a heterogeneous population of stromal fibroblasts with different molecular profiles that change during tumorigenesis. Both immunosuppressive and immunosuppressive subsets of CAFs can coexist in the stroma of a single tumor. Based on the heterogeneity of the intertumor stroma, attempts are being made to classify PDAC and predict the course of the disease.

[The first experience of endovascular treatment of chronic subdural hematomas with non-adhesive embolization materials of various viscosities: Squid 12 and 18]

Chronic subdural hematomas (CSH) usually require surgical evacuation via a burr hole or craniotomy. Certain incidence of recurrent postoperative CSH is known. Middle meningeal artery (MMA) embolization has been described as an alternative surgery for new or recurrent CSH or as a preventive measure to reduce the risk of postoperative recurrence. The authors report successful MMA embolization with 2 non-adhesive embolic agents of various viscosities (SQUID 12 and SQUID 18, Balt USA, Irvine, CA, USA) for recurrent postoperative CSH in a 44-year-old woman.

Rat Blood Leukocytes after Intravenous Injection of Magnetoliposomes on the Basis of Nanomagnetite

The structure of blood neutrophils, eosinophils, monocytes, and lymphocytes and differential white blood count in adult rats were studied over 120 days after a single intravenous injection of magnetoliposomes based on nanomagnetite. Magnetoliposomes had no effect on the structure of neutrophils, eosinophils, monocytes, and lymphocytes. At the same time, injection of a suspension of magnetoliposomes based on magnetite nanoparticles led to a decrease in lymphocyte count and an increase in the count of monocytes and band and segmented neutrophils in the blood. These changes were transient and the parameters returned to normal by day 40-60 after injection.

Single-beam multimodal nonlinear-optical imaging of structurally complex events in cell-cycle dynamics

We demonstrate a multimodal nonlinear-optical imaging that combines second- and third-harmonic generation (SHG and THG) with three-photon-excited fluorescence (3PEF) as a means to resolve fine details of the cell structure and trace its transformations throughout structurally complex episodes of cell-cycle dynamics, including the key stages and signatures in cell division. When zoomed in on cell mitosis, this technique enables a high-contrast multimodal imaging of intra- and extracellular signatures of cell division, detecting, via a multiplex, 3PEF/SHG/THG readout, a remarkable diversity of shapes, sizes, and symmetries in a truly single-beam setting, with no need for beam refocusing or field-waveform re-adjustment.

Evaporation kinetics of a polydisperse ensemble of drops

A mathematical model of the evaporation of a polydisperse ensemble of drops, with allowance for a nonlinear 'diffusion' term in the kinetic equation for the population density distribution function, is developed. The model describes the interaction of a gas phase with vaporizing drops: it has great potential for application in condensed matter physics, thermophysics and engineering devices (e.g. spray drying, cooling, power engineering). The kinetics of heat transfer between phases is theoretically studied. An analytical solution to the integro-differential equations of the process of droplet evaporation is found in a parametric form. Analytical solutions in the presence and absence of the 'diffusion' term are compared. It is shown that the fluctuations in particle evaporation rates ('diffusion' term in the Fokker-Planck equation) play a decisive role in the evolutionary behaviour of a polydisperse ensemble of vaporizing liquid drops. This article is part of the theme issue 'Transport phenomena in complex systems (part 1)'.

Multimodal nonlinear-optical imaging of nucleoli

Multimodal nonlinear microscopy combining third-harmonic generation (THG) with two- and three-photon-excited fluorescence (2PEF and 3PEF) is shown to provide a powerful resource for high-fidelity imaging of nucleoli and nucleolar proteins. We demonstrate that, with a suitably tailored genetically encoded fluorescent stain, the 2PEF/3PEF readout from specific nucleolar proteins can be reliably detected against the extranucleolar 2PEF/3PEF signal, enabling high-contrast imaging of the key nucleolar ribosome biogenesis components, such as fibrillarin. THG is shown to provide a versatile readout for unstained nucleolus imaging in a vast class of biological systems as different as neurons in brain slices and cultured HeLa cells.

[Endovascular treatment of extracranial dissecting aneurysms of cervical arteries]

BACKGROUND

Dissecting aneurysms of extracranial cervical arteries are a rare vascular pathology. To date, there is no consensus on the choice of optimal surgical approach for these aneurysms.

OBJECTIVE

To evaluate the effectiveness of endovascular treatment of various extracranial dissecting aneurysms.

MATERIAL AND METHODS

There were 19 patients with 21 extracranial dissecting aneurysms for the period from January 1, 2013 to October 19, 2020. Clinical examination, ultrasound and neuroimaging data were considered to determine surgical intervention.

RESULTS

Nineteen patients underwent 20 intravascular interventions: aneurysm embolization with detachable coils with stent-assistance (n=9), flow-diverting stent implantation (n=5), arterial reconstruction with a stent for carotid stenting (n=3), aneurysm embolization with balloon assistance (n=1), aneurysm embolization with detachable coils without assistance (n=2). There were no complications. All patients were discharged without neurological impairment after 1-5 days. Long-term results of control angiography were analyzed within 1-19 months in 12 patients. All aneurysms were completely occluded. Asymptomatic occlusion of flow-diverting stent together with aneurysm occurred in 1 patient with low compliance to antiplatelet therapy. Other 6 patients are scheduled for elective angiography.

CONCLUSION

Extracranial dissecting aneurysms of cervical arteries require vigilance due to their rare occurrence and risk of severe complications. In our opinion, intravascular interventions are advisable for these patients as effective and safe procedures.

Osteogenic Potential of Decellularized Tooth Matrix

We studied the possibility of using decellularized tooth matrix as a scaffold to restore bone tissue. It was found that mesenchymal stem cells underwent spontaneous osteogenic differentiation on the decellularized tooth matrix, which makes it possible to use it as a natural allograft in the treatment of resorption of alveolar bone tissue.

Behavioral Responses and Immune and Cytogenetic Parameters of Food-Restricted Mice

The experiments on mice showed that subchronic food restriction to 40 and 8% of unrestricted ration is a strong stressor inducing devastation of lymphoid organs, primarily the thymus and spleen. The mice in the group with severe food restriction (8% of normal ration) demonstrated increased front paw grip force. We also observed an increase in spontaneous motor activity in these animals correlated with food restriction. Food deprivation led to inhibition of proliferative activity of the bone marrow cells and suppression of erythropoiesis. Moreover, severe food restriction was accompanied by a decrease in the number of double-strand DNA breaks evaluated by the release of γH2AX⁺-cells and the ratio of polychromatophilic erythrocytes.

Dissolution of polydisperse ensembles of crystals in channels with a forced flow

A non-stationary integro-differential model describing the dissolution of polydisperse ensembles of crystals in channels filled with flowing liquid is analysed. The particle-size distribution function, the particle flux through an arbitrary cross-section of the channel, the particle concentration profile, as well as the disappearance intensity of particles are found analytically. It is shown that a nonlinear behaviour of solutions is completely defined by the source term of particles introduced into the channel. In particular, the model approximately describes the processes of dissolution and transport of drug microcrystals to the target sites in a living organism, taking into account complex dissolution kinetics of drug particles. This article is part of the theme issue 'Patterns in soft and biological matters'.

Cell-specific three-photon-fluorescence brain imaging: neurons, astrocytes, and gliovascular interfaces

We present brain imaging experiments on rat cortical areas, demonstrating that, when combined with a suitable high-brightness, cell-specific genetically encoded fluorescent marker, three-photon-excited fluorescence (3PEF), enables subcellular-resolution, cell-specific 3D brain imaging that is fully compatible and readily integrable with other nonlinear-optical imaging modalities, including two-photon-fluorescence and harmonic-generation microscopy. With laser excitation provided by sub-100-fs, 1.25-µm laser pulses, cell-specific 3PEF from astrocytes and their processes detected in parallel with a three-photon-resonance-enhanced third harmonic from blood vessels is shown to enable a high-contrast 3D imaging of gliovascular interfaces.

Update of ion-optical system of neutral beam of Tokamak à Configuration Variable

An injector of fast deuterium atoms for plasma heating was designed and installed at the Tokamak à Configuration Variable (TCV). The neutral beam can deliver 1 MW power to the plasma in 2 s pulses. An ion beam of the injector is formed by a triode multislit ion-optical system with spherical electrodes which provide ballistic focusing. Tests at TCV revealed that the total angular divergence of the neutral beam across the slits exceeded the expected value more than twice. It was finally established that this increase in divergence was caused by the asymmetry of the chamfers at the slit edges of the plasma electrode. The redesigned shape of the slits of the plasma grid together with precise machining significantly improved the beam quality. Experimental testing proved that the neutral beam profile in the direction across the grid slits became very close to the expected value.

Phase transformations in metastable liquids combined with polymerization

This paper is concerned with the theory of nucleation and growth of crystals in a metastable polymer melt with allowance for the polymerization of a monomer. A mathematical model consisting of the heat balance equation, equations governing the particle-radius distribution function and the polymerization degree is formulated. The exact steady-state analytical solutions are found. In the case of unsteady-state crystallization with polymerization, the particle-size distribution function is determined analytically for different space-time regions by means of the Laplace transform. Two functional integro-differential equations governing the dimensionless temperature and polymerization degree are deduced. These equations are solved by means of the saddle-point technique for the evaluation of a Laplace-type integral. The time-dependent distribution function, temperature and polymerization degree at different polymerization rates and nucleation kinetics are derived with allowance for the main contribution to the Laplace-type integral. In addition, the general analytical solution by means of the saddle-point technique and an example showing how to construct the analytical solutions in particular cases are given in the appendices. The analytical method developed in the present paper can be used to describe the similar phase transition phenomena in the presence of chemical reactions. This article is part of the theme issue 'Heterogeneous materials: metastable and non-ergodic internal structures'.

[Dimeric bisbenzimidazoles suppress the herpes simplex virus and human cytomegalovirus infections in cell сultures]

Antiviral activity of new AТ-specific fluorescent symmetric dimeric bisbenzimidazoles of DBА(n) series was assessed in the cell models of infections caused by type 1 herpes simplex virus (HSV1) and human cytomegalovirus (CMV). In DBA(n) molecules bisbenzimidazole fragments are bound to an oligomethylene liner with varied number of methylene groups in the linker (n = 1, 3, 5, 7, 9, 11). In contrast to DB(n) dimeric bisbenzimidazoles, in DBA(n) series terminal fragments of macromolecules contain N-dimethylaminopropylcarboxamide groups instead of N-methylpiperazine groups. DBА(n) compounds better dissolve in water, pass across plasma and nuclear membrane, and stain DNA in living cells. DBA(1) and DBA(7) produced therapeutic effects in HSV1 infection; DBA(7) completely suppressed the infection. DBA(11) displayed in vitro therapeutic activity in HSV1 and CMV infections. In addition, DBA(7) and DBA(1) showed microbicidal activity. Thus, DBA(11), which is active against two viruses causing severe diseases with serious health consequences for immunodeficient individuals, should be further investigated. High antiviral activity of DBA(7) in all test models indicates that this compound is a promising active agent for innovative antiviral drugs.

Peculiarities of Osteogenesis by Periosteal Cells after Experimental Ectopic Transplantation

We carried out a comparative study of the features of osteogenesis from the progenitor osteogenic periosteal cells in rabbit and human. At the initial stages, high osteogenic potential of both human and rabbit periosteal cells was observed. However, at the later stages, the cell response favors resorption of the new bone tissue formed from periosteal cells in rabbits, but does not affect the bone tissue formed from human progenitor osteogenic periosteal cells. These functional characteristics of rabbit periosteal cells should be considered when planning the experiment.

Analytical solutions of mushy layer equations describing directional solidification in the presence of nucleation

The processes of particle nucleation and their evolution in a moving metastable layer of phase transition (supercooled liquid or supersaturated solution) are studied analytically. The transient integro-differential model for the density distribution function and metastability level is solved for the kinetic and diffusionally controlled regimes of crystal growth. The Weber-Volmer-Frenkel-Zel'dovich and Meirs mechanisms for nucleation kinetics are used. We demonstrate that the phase transition boundary lying between the mushy and pure liquid layers evolves with time according to the following power dynamic law: [Formula: see text], where Z₁(t)=βt^7/2 and Z₁(t)=βt² in cases of kinetic and diffusionally controlled scenarios. The growth rate parameters α, β and ε are determined analytically. We show that the phase transition interface in the presence of crystal nucleation and evolution propagates slower than in the absence of their nucleation.This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'.

Symmetric dimeric bisbenzimidazoles DBP(n) reduce methylation of RARB and PTEN while significantly increase methylation of rRNA genes in MCF-7 cancer cells

BACKGROUND

Hypermethylation is observed in the promoter regions of suppressor genes in the tumor cancer cells. Reactivation of these genes by demethylation of their promoters is a prospective strategy of the anticancer therapy. Previous experiments have shown that symmetric dimeric bisbenzimidazoles DBP(n) are able to block DNA methyltransferase activities. It was also found that DBP(n) produces a moderate effect on the activation of total gene expression in HeLa-TI population containing epigenetically repressed avian sarcoma genome.

PRINCIPAL FINDINGS

It is shown that DBP(n) are able to penetrate the cellular membranes and accumulate in breast carcinoma cell MCF-7, mainly in the mitochondria and in the nucleus, excluding the nucleolus. The DBP(n) are non-toxic to the cells and have a weak overall demethylation effect on genomic DNA. DBP(n) demethylate the promoter regions of the tumor suppressor genes PTEN and RARB. DBP(n) promotes expression of the genes RARB, PTEN, CDKN2A, RUNX3, Apaf-1 and APC "silent" in the MCF-7 because of the hypermethylation of their promoter regions. Simultaneously with the demethylation of the DNA in the nucleus a significant increase in the methylation level of rRNA genes in the nucleolus was detected. Increased rDNA methylation correlated with a reduction of the rRNA amount in the cells by 20-30%. It is assumed that during DNA methyltransferase activity inhibition by the DBP(n) in the nucleus, the enzyme is sequestered in the nucleolus and provides additional methylation of the rDNA that are not shielded by DBP(n).

CONCLUSIONS/SIGNIFICANCE

It is concluded that DBP (n) are able to accumulate in the nucleus (excluding the nucleolus area) and in the mitochondria of cancer cells, reducing mitochondrial potential. The DBP (n) induce the demethylation of a cancer cell's genome, including the demethylation of the promoters of tumor suppressor genes. DBP (n) significantly increase the methylation of ribosomal RNA genes in the nucleoli. Therefore the further study of these compounds is needed; it could lead to the creation of new anticancer agents.

DNA sequence-specific dimeric bisbenzimidazoles DBP(n) and DBPA(n) as inhibitors of H-NS silencing in bacterial cells

DNA sequence-specific fluorescent dimeric bisbenzimidazoles DBP(n) and DBPA(n), noncovalently interacting with A-T pairs in the minor groove of double-stranded DNA were used for studying and monitoring the expression of histone-like H-NS-dependent promoters. Histone-like H-NS selectively binds to AT-rich segments of DNA and silences a large number of genes in bacterial chromosomes. The H-NS-dependent promoters of Quorum Sensing (QS)-regulated lux operons of the marine bacteria mesophilic Aliivibrio fischeri, psychrophilic Aliivibrio logei were used. Escherichia coli lux biosensors were constructed by cloning fragments bearing QS-regulated promoters into the vector, thereby placing each fragment upstream of the promoterless Photorhabdus luminescens luxCDABE genes. It was shown that the dimeric bisbenzimidazoles DBP(n) and DBPA(n) counteract the H-NS silencing activity. Thus, the presence of DBP(n) or DBPA(n) in the medium leads to an approximately 10-100-fold increase in the level of transcription of QS promoters in E. coli hns⁺. The largest decrease in the level of H-NS repression was observed using ligands containing a linker with a length of ca. 18Å, such as DBP(2) and DBPA(2). Ligands containing linkers with n=1 and 3 are an order of magnitude less active; ligands with n=4 are inactive. DBPA(2) exhibits activity starting with a concentration of 0.5μM; the minimum concentration of DBP(2) is 5-7 times higher. It is suggested that A-T pairs located at five nucleotide pair intervals, which correspond to the linker length in highly active ligands with n=2, play a key role in the structure of H-NS-binding sites in QS-regulated promoters.

[Role of tenascin С in triple-negative breast cancer]

AIM

to establish a relationship between the main markers tumor stem cells (TSCs), CD44, and CD24, the level of tenascin C production, and chemoresistance in triple-negative breast cancer (BC).

SUBJECTS AND METHODS

Thirty biopsy specimens from triple-negative BC patients who had conventionally received preoperative chemotherapy followed by surgery were selected in the investigation. All the selected patients were conventionally assigned to neoadjuvant polychemotherapy (PCT) with paclitaxel and carboplatin. The surgical specimens were analyzed in relation to the degree of a tumor morphological response to PCT. The magnitude of the health-promoting effect of neoadjuvant therapy was evaluated according to the residual cancer burden (RCB) system using an on-line calculator; RCB was categorized into classes (from RCB-0 to RCB-III). The markers CD44, СD24, and tenascin C were identified by the standard immunoperoxidase method in the primary biopsies.

RESULTS

Varying morphological responses of triple-negative breast cancer to PCT were revealed, which showed resistance in 60% of the cases. The chemoresistance found in most (87%) cases coincided with the identification of the CD44+/CD24low/- profile. The detection of the higher production of the extracellular matrix tenascin C participating in the formation of the TSC niche fully combined with the CD44+/CD24low/- phenotype; while the maximum response to tenascin C was noted in the cases differing in not only a lack of responses to PCTs, but also in the most aggressive course in conjunction with metastatic disease.

CONCLUSION

Immunohistochemical analysis shows that the unique association between the CD44+/CD24low/- phenotype and the pronounced production of tenascin C may have a prognostic potential, prospectively indicating the inefficiency of neoadjuvant PCT, in particular that with platinum derivatives, which is used for the standard treatment of triple-negative BC. Taking into account the role of tenascin C in invasion, metastasis, and chemoresistance, it per se may be considered as a promising target for the targeted and/or combined therapy of triple-negative BC.

[Extrapontine myelinolysis developed after aneurysmal subarachnoid hemorrhage (a case report and literature review)]

TOPICALITY

Central pontine and extrapontine myelinolysis is a rare and dangerous form of the demyelinating process of undefined origin, the development of which is associated with a very low sodium level in the blood (hypernatremia).

OBJECTIVE

To describe a rare case of extrapontine myelinolysis as a complication occurring in the hemorrhagic period of anterior communicating artery aneurysm rupture as well as to demonstrate that this condition can be diagnosed intravitally.

CONCLUSION

Clinical vigilance of extrapontine myelinolysis may promote the timely diagnosis and treatment of this disease, which is a potential cause of death. Pulse-therapy with glucocorticoids provides the opportunity to achieve regression of neurological symptoms and to stabilize the patient's condition.

[The highly specific and sensitive analysis of repertoire of serum antibodies using peptide microchips in patients with diagnosis of breast cancer.]

Nowadays, the search for new biomarkers of cancer is actual for early diagnostic. The antibodies against antigens associated with tumors arouse an interest as an alternative to the present biomarkers. The alteration of quantity and specificity of antibodies in blood serum indicates processes occurring in the organism, including development of oncologic diseases. The article presents the results of analysis of repertoire of antibodies (immunosignatures) using peptide micro-chips in patients with diagnosis of breast cancer. The study established 119 informative peptides out of 330 034 peptides, presented on the microchip. The binding of antibodies with them demonstrates statistically significant intergroup values (p<0.001). This panel of peptides is effective in discerning sera of patients and healthy donors with high sensitivity and specificity. The evaluation of repertoire of antibodies interacting with panel of synthetic peptides can be used in development of diagnostic tests in case of detection of breast cancer at early stages.

[STUDYING GASTRIC ULCERATION EFFECT OF A NEW DRUG INTENDED FOR TREATMENT OF CHRONIC INFLAMMATORY DISEASES OF KIDNEYS AND URINARY TRACT.]

Gastric ulceration properties (gastrointestinal toxicity) of the sodium salt of 4-(0-β-D-glucopyranosyloxy) benzoic acid, a new nonsteroidal anti-inflammatory drug (NSAID) intended for the treatment of chronic inflammatory diseases of the kidney and urinary tract, have been tested on laboratory animals. Acute NSAID-induced gastropathy was induced in rats by oral administration of indomethacin, nimesulide, diclofenac, acetylsalicylic acid and the new drug. Test animals were killed by instantaneous decapitation 4 h after treatment and their gastrointestinal tracts were studied by pathomorphological methods on micropreparations and histological sections of gastric mucosa. It was established that the new drug, in contrast to reference NSAIDS, did not exhibit gastropathic action on the gastric mucosa.

ANTI-INFLAMMATORY ACTIVITY OF SODIUM SALT OF 4-(O-β-D-GLUCOPYRANOSYLOXY)BENZOIC ACID

We have evaluated the anti-inflammatory activity of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid in comparison to well-known nonsteroidal anti-inflammatory drugs (NSAIDs). Carrageenan suspension (1%, 0.1 mL) was injected into subplantar region of the right hindpaw of rats (n = 12) pretreated (7 days and 60 min before carrageenan injection) intragastrically with methyl ester of 4(β-D-glucopyranosyloxy)benzoic acid (20 mg/kg), acetylsalicylic acid (20 mg/kg), 4-hydroxybenzoic acid (20 mg/kg), or vehicle (2 mL of purified water). Paw edema volume was measured plethysmographically at 1, 2 and 4 h after carrageenan injection. The results showed that intragastric administration of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid in a dose of 20 mg/kg for 7 days decreased the intensity of experimental inflammation.

Early Response of Mouse Bone Mrrow Cells to Short-Term Irradiation in a Wide Range of Doses

Experiments on mice irradiated with γ-rays in a wide range of doses, from 0.5 to 400 cGy and the bone marrow have shown cytogenetic and cytological effects ranging from I cGy dose 24 hours after exposure to radiation. Dose-independent reduction of the number of nucleated cells in the bone marrow, normal or even elevated levels of mitotic activity, and extreme dependence of the type of chromosomal aberrations on the radiation dose with the maximum in the region of 7.5 cGy were observed in the dose range from 1 to 20 cGy. A linear dose-dependent decrease of the cell.number in the bone marrow, a decreased mitotic activity and increased number of aberrant mitosis were marked in the dose range from 20 to 400 cGy. The findings are discussed in terms of their application for explaining the mechanisms of hormesis, adaptive response, as well as the appropriateness of accounting the parameters studied for solving problems of regulation of permissible doses.

Waves of c-Fos and Arc Proteins Expression in Neuronal Populations of the Hippocampus in Response to a Single Episode of New Experience

Accumulation of c-Fos and Arc proteins in neurons in different regions of the hippocampus after single trial of contextual fear conditioning was studied by using immunohistochemical staining. We found that the dynamics of the c-Fos and Arc expression has a biphasic pattern: the first peak was observed in 15-30 min after learning and the second less pronounced peak in 1-3 h. Induction of Arc occurred earlier than c-Fos and the overall dynamics of the two waves slightly varied in the dentate gyrus and hippocampal CA1 and CA3 fields. The findings open the possibility of mapping the cognitive neural networks of the brain with higher temporal resolution and draw attention to fluctuations of hippocampal activity after a single brief episode of new experience.

Note: Arc discharge plasma source with plane segmented LaB6 cathode

A plane cathode composed of close-packed hexagonal LaB6 (lanthanum hexaboride) segments is described. The 6 cm diameter circular cathode is heated by radiation from a graphite foil flat spiral. The cathode along with a hollow copper anode is used for the arc discharge plasma production in a newly developed linear plasma device. A separately powered coil located around the anode is used to change the magnetic field strength and geometry in the anode region. Different discharge regimes were realized using this coil.

[Tumor stem cells in breast cancer]

High mortality from breast cancer is associated with the high heterogeneity of tumor and the frequent recurrences of the pathological process, which are due to the presence of tumor stem cells. The review considers the biological properties of tumor stem cells, the molecular mechanisms of their regulation, interaction with the microenvironment, and their role in the heterogeneity of the morphological and clinical forms of breast cancer.

[Modern problems and main ways of imorovement of disinfecting art in Armed Forces]

The article states the reasons defining the high relevance and significance of disinfection measures in modern conditions, reports general and specific problems of ensuring disinfection during medical service day-to-day activities. The directions of development of chemical and technical disinfectants and methods for'their use on different objects and under various climatic conditions are determined. It was shown that the crucial condition for implementation of theoretical and practical ways of improving disinfection affairs is a comprehensive approach based on concerted efforts of all authorities of Russian Armed Forces Medical Services, research and sanitary-epidemiological institutions, as well as relevant chars of the Military Medical Academy in close cooperation with representatives of domestic industry.

[CYTOGENETIC EFFECTS IN MICE BONE MARROW AFTER IRRADIATION BY FAST NEUTRONS]

Mechanisms of damaging mice bone marrow cells by 1.5 MeV neutrons at the dose of 25-250 cGy, dose rate of 23.9 cGy/s and γ-quants ⁶⁰Co as a standard radiation were studied. The mitotic index and aberrant mitoses in marrow preparations were counted in 24 and 72 hours after irradiation. Coefficients of relative biological effectiveness (RBE) of fast neutrons 24 and 72 hours post irradiation calculated from mitotic index reduction and aberrant mitoses formation were within the range from 4.1 ± 0.1 to 7.3 ± 0.1. Mean time of the existence of chromosomal aberrations in marrow cells was determined. For the specified doses from γ-rays, the period of aberrations existence was 1.4-1.1 cycles and for neutrons, 1.0-0.6 cycles. Morphologic analysis of neutron-induced damages and ratio of the most common breaks demonstrated a high production of bridges, which outnumbered cells with fragments in 3 to 4 times suggesting a more destructive effect on the genetic structures of cells. RBE of fast neutrons is a variable that grows with a radiation dose. Moreover, RBE estimated after 72 hours exceeded values it had 24 hours after irradiation.

[DIURETIC ACTIVITY OF 4-O-CARBOXYPHENYL-D-GLUCOPYRANOSIDE SODIUM SALT ADMINISTERED VIA DIFFERENT ROUTES]

It was compared the diuretic activity of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid for enteral (intragastric) and parenteral ways of administration. The test substance was administered enterally and parenterally (subcutaneously in the region of the withers) in a daily dose of 18 µmol/kg for the first seven days and in a dose of 54 mmol/kg for the next seven days. Diuretic activity of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid was evaluated in terms of urine volume. Urine was analyzed for creatinine and the concentration of sodium, potassium and chloride ions. Experiments showed that the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid produced a diuretic effect only for the enteral administration route.

Recurrence of Cerebral Arteriovenous Malformations Following Resection in Adults

BACKGROUND:

Complete surgical resection of arteriovenous malformations (AVMs), documented by postoperative angiography, is generally felt to represent cure, obviating the need for long-term follow-up imaging. Although AVM recurrence has been reported in the pediatric population, this phenomenon has only rarely been documented in adults. Recurrence after treatment solely with embolization, however, has been reported more frequently. Thus, patients undergoing multimodal therapy with surgery following preoperative embolization may also be at higher risk for recurrence.

OBJECTIVE:

To determine if preoperative embolization contributes to recurrences of AVMs after complete surgical resection.

METHODS:

A retrospective study of patients undergoing AVM resection was performed. Those with complete surgical AVM resection, confirmed by negative early postoperative cerebral angiography and with available follow-up angiographic imaging –6 months postoperatively were included.

RESULTS:

Two hundred three patients underwent AVM resection between 1995 and 2012. Seventy-two patients met eligibility criteria. There were 3 recurrences (4%). Deep venous drainage and diffuse type of AVM nidus were significantly associated with recurrence. Although preoperative embolization did not reach statistical significance as an independent risk factor, radiographic data supported its role in every case, with the site of recurrence correlating with deep regions of nidus previously obliterated by embolization.

CONCLUSION:

AVM recurrences in the adult population may have a multifactorial origin. Although deep venous drainage and diffuse nidus are clearly risk factors, preoperative embolization may also be a contributing factor with the potential for recurrence of unresected but embolized portions of the AVM. Follow-up angiography at 1 to 3 years appears to be warranted.

Progress in Mirror-Based Fusion Neutron Source Development

The Budker Institute of Nuclear Physics in worldwide collaboration has developed a project of a 14 MeV neutron source for fusion material studies and other applications. The projected neutron source of the plasma type is based on the gas dynamic trap (GDT), which is a special magnetic mirror system for plasma confinement. Essential progress in plasma parameters has been achieved in recent experiments at the GDT facility in the Budker Institute, which is a hydrogen (deuterium) prototype of the source. Stable confinement of hot-ion plasmas with the relative pressure exceeding 0.5 was demonstrated. The electron temperature was increased up to 0.9 keV in the regime with additional electron cyclotron resonance heating (ECRH) of a moderate power. These parameters are the record for axisymmetric open mirror traps. These achievements elevate the projects of a GDT-based neutron source on a higher level of competitive ability and make it possible to construct a source with parameters suitable for materials testing today. The paper presents the progress in experimental studies and numerical simulations of the mirror-based fusion neutron source and its possible applications including a fusion material test facility and a fusion-fission hybrid system.

[Use of diagnostic templates at stages of prosthetics treatment with implant-retained restorations]

The comparative analysis of efficiency of various types of diagnostic templates for planning orthopedic treatment of 50 patients with partial or complete absence of teeth was performed. The patients were divided in 3 groups according to template manufacturing technique. All diagnostic templates made in accordance with clinical conditions allowed transfering digital data of the scheduled prosthetic construction for virtual implantation planning. Advantages and pitfalls of each template type are discussed.

DNA specific fluorescent symmetric dimeric bisbenzimidazoles DBP(n): the synthesis, spectral properties, and biological activity

A series of new fluorescent symmetric dimeric bisbenzimidazoles DBP(n) bearing bisbenzimidazole fragments joined by oligomethylene linkers with a central 1,4-piperazine residue were synthesized. The complex formation of DBP(n) in the DNA minor groove was demonstrated. The DBP(n) at micromolar concentrations inhibit in vitro eukaryotic DNA topoisomerase I and prokaryotic DNA methyltransferase (MTase) M.SssI. The DBP(n) were soluble well in aqueous solutions and could penetrate cell and nuclear membranes and stain DNA in live cells. The DBP(n) displayed a moderate effect on the reactivation of gene expression.

[SEARCHING FOR NEW SYNTHETIC DIURETICS]

This study was aimed at estimation of the diuretic and saluretic activity of 4-nitrophenyl-O-β-D-glucopyranoside and its aglicon 4-nitrophenol in rats. Test animals daily received 4-nitrophenyl-O-β-D-glucopyranoside (group 1) and 4-nitrophenol (group 2) intragastrically in 2 mL of distilled water in a dose of 18 µmol/kg from 1st to 7th day and 54 µmol/kg from 8th to 14th days. During the experiment, the most pronounced diuretic activity was observed for 4-nitrophenyl-O-β-D-glucopyranoside in a dose of 54 µmol/kg, which increased the diuresis in rats 2.5 times as compared to the control value.

[Cytogenetic investigations of bone marrow cells from mice exposed onboard biosatellite "Bion-M1"]

The results of studying the mitotic activities and chromosomal aberrations in bone marrow cells from C57/BL6N mice with the help of the anaphase technique in 12 hours after completion of the 30-day "Bion-M1" mission and ground-based experiment using flight equipment are presented. A statistically reliable decline of the mitotic activity (0.74%) was found in cells taken from the space flown animals. In the ground-based experiment, a statistically reliable downward trend in proliferative activity (1.37%) was revealed after the comparison with groups of vivarium control (1.46-1.53%). In both experiments mice increased the number of initial mitotic phases (prophase + metaphase) relative to the sum of anaphases and telophases. The number of aberrant mitoses grew reliably in the group of flight animals by 29.7%, whereas in the ground-based experiment an upward trend was insignificant as their number increased up to 2.3% only. In the vivarium controls aberrant mitoses constituted 1.75-1.8%. An increase in chromosomal aberrations was largely due to such abnormalities as fragments. These findings seem to have been a result of summation of the effects of radiation and other stressful factors in space flight.

[ZINK IS ACTIVATOR OF ENTERAL CALCIUM METABOLISM]

Experiments on goats and rabbits showed that zinc supplement to the diet leads to calcium concentration rise in muscle, bone and blood of animals. However, this rise was not adequate to increase in.zinc consumption. The bulk of alimentary zinc stayed in soluble fraction, dense endogen fraction and infusoria fraction of digesta and stimulated calcium release from food particles, it's accumulation in digesta fractions and calcium utilization on the whole. Authors estimate animal digesta as homeostatic, spatial organized, endogenic formation in which zinc and calcium are functionally dependent through enteral mucosa.

[CYSTEAMINE-INDUCED MODIFICATION OF CYTOGENETIC DAMAGES TO THE CORNEAL EPITHELIUM OF MICE EXPOSED TO CORPUSCULAR RADIATION WITH VARYING LINEAR TRANSFER ENERGIES]

Cytogenetic damages to cells of the corneal epithelium were studied in mice exposed to protons (10, 25, 50 and 645 MeV), ions of boron, carbon and neon, and X-rays (180 keV) within the dose range from 25 to 750 cGy and injected with a radioprotector. Animals were subjected to a single exposure. The protective effect of β-mercaptoethylamine was tested in the experiment. The radioprotector (0.2 ml) was introduced intraperitoneally 30 minutes before exposure in 350 mI/kg dose. Control animals received the same amount of sodium chloride solution. The animals were sacrificed by cervical dislocation in 24 and 72 hrs. after exposure. It was shown that cysteamine effectively protects in vivo corneal epithelium cells of mice exposed to electromagnetic radiation or protons in a broad energy spectrum (10 to 645 MeV), and to a broad range of radiation doses (25 to 750 cGy), as judged from levels of aberrant mitosis and mitotic activity. The radioprotector exhibited the highest effectiveness in animals exposed to the doses of 50 to 300 cGy. These findings prove that cysteamine may potentially be used for pharmacological protection from protons. The radioprotector failed to prevent chromosomal aberrations after exposure to heavy charged particles of boron, carbon and neon, which implies the need to design radioprotectors against this type of corpuscular radiation specifically.

[Cytogenetic damage to the corneal epithelium of mice due to the in vivo exposure to ionizing radiation with different levels of linear energy transfer]

Damages to corneal epithelium cells were studied in mice irradiated by protons with the energies of 10, 25, 50 and 645 MeV, 60Co γ-quanta and accelerated ions of boron, carbon and neon with the energies of 7.5; 2.5 and 6.0 MeV/nucleon, respectively. X-rays (180 keV) were used as a standard radiation. Animals were exposed to a single dose in the range from 25 to 760 cGy. The mitotic index and aberrant mitoses were counted in corneal preparations in 24 hrs after irradiation. No matter the type of radiation, the mitotic index had an inverse dose dependence, i.e. the higher the dose, the lower the mitotic index. Exposure to all types of radiation resulted in a sharp increase in the number of chromosomal aberrations in the corneal epithelium; frequency of aberrations was a function of dose and type of radiation. The number of chromosomal aberrations displayed a peculiar direct dose dependence irrespective of type of radiation; however, heavy ions of carbon and boron are the most damaging to the cytogenetic apparatus of epithelial cells. Protons at the Bragg peak and ensuing fall, and of 50 MeV also contribute to the production of chromosomal aberrations as compared with sparsely ionizing gamma- and X-rays and high-energy protons with low linear energy transfer. Coefficients of relative biological effectiveness were calculated based on the mitotic index and evidence of aberrant mitosis.

[DEMONSTRATION OF LIKELIHOOD OF THE NEGATIVE EFFECT OF PHYSICAL PROTECTION DURING TOTAL PROTON IRRADIATION OF MICE]

The experiments were performed with outbred CD-1 male mice (SPF category). Total irradiation at 1.0; 2.5 and 5.0 Gy by protons with the average energy of 170 MeV was conducted in a level medical beam of the phasotron at the Joint Institute of Nuclear Investigations. Targets were 2 points of in-depth dose distribution, i.e. beam entrance of the object, and modified Bragg peak. As a physical protector, the comb filter increases linear energy transfer (LET) of 170 MeV entrance protons from 0.49 keV/μm to 1.6 keV/μm and, according to the bone marrow test, doubles the biological effectiveness of protons when comparing radiation doses that cause 37% inhibition of blood cell formation in the bone marrow. Physical protection increases dose rate from 0.37 Gy/min for entrance protons to 0.8 Gy/min for moderated protons which more than in thrice reduces time of irradiation needed to reach an equal radiobiological effect.