[Pediatric sensorineural hearing loss related COVID-19. Clinical cases]. / Sensonevral'naya tugoukhost' v detskom vozraste, assotsiirovannaya s COVID-19. Klinicheskie nablyudeniya.

COVID-19 is an acute respiratory coronavirus infection in 2019 caused by the SARS-CoV-2 virus. Currently, the number of neurological complications in the acute or delayed period of coronavirus disease is increasing, including peripheral disorders of the auditory analyzer. OBJECTIVE: To present clinical cases of sensorineural hearing loss in children under 5 years of age after a novel coronavirus infection. MATERIAL AND METHODS: We report 3 cases of unilateral and 1 case of bilateral acquired deep sensorineural hearing loss, while the association with SARS-CoV-2 has been confirmed anamnetically and/or laboratory. RESULTS: The SARS-CoV-2 virus can have a depressing effect on the cochlea on its own or enhance the toxic effect of viruses during the recovery period after COVID-19. The true frequency of acute sensorineural hearing loss of infectious origin in childhood and, as its outcome, the formation of persistent hearing impairment has not been determined. CONCLUSION: Viruses are volatile, contagious, and clinically dangerous due to their complications. Vaccination is the most effective measure for the prevention of infectious diseases.

Comparative Pharmacoeconomic Effectiveness of Interleukin-17 Inhibitors for the Treatment of Ankylosing Spondylitis.

The objective of this study was to compare the clinical efficacy and cost-effectiveness of IL-17 inhibitors (SEC, IXE, NTK) in the treatment of adult patients with ankylosing spondylitis (AS) in the healthcare system of the Russian Federation. Materials and methods. The study is a sub-analysis of a previously published systematic review and network meta-analysis of the comparative efficacy of biologics in adult patients with AS in the Russian Federation. NNT values were calculated for BASDAI 50 and ASAS 20/40 after 16 weeks of therapy for all studied drugs. CpR was estimated for each biologic after 16 weeks and one year of therapy. Additionally, we carried out an assessment of the financial burden of the most cost-effective strategies for the treatment of AS. The use of NTK is characterized by an average of no more than three patients needed to treat to achieve one ASAS 20/40 or BASDAI 50 response, while on IXE and SEC no more than 4-5 patients need to be treated, depending on the estimated effectiveness criterion. According to CpR estimate, NTK is the most cost-effective IL-17 inhibitor for the treatment of AS, both after 16 weeks and after one year of therapy. The obtained results make it possible to compare the effectiveness of IL-17 inhibitors from a clinical and economic points of view and can be used both in decision making on treatment strategies for individual patients and at the population level when deciding on the reimbursement of drugs.

[Myoclonus of the middle ear]. / Mioklonus myshts srednego ukha.

The objective of the present study was to overview the foreign literature concerning middle ear myoclonus (MEM) known to be the most common cause of the manifestations of objective tinnitus. The authors reports two typical clinical cases of myoclonus of the middle ear. The present article is aimed at the enhancement of the awareness of the otorhinolaryngologists, audiologists, and neurologists of the condition of interest as a way to promote the further progress in its treatment.

[The modern view of the radiodiagnostic methods applied for determining the position of the electrode array in cochlear implantation surgery]. / Sovremennyi vzgliad na metody luchevoi diagnostiki, primeniaemye dlia opredeleniia polozheniia élektrodnoi reshetki pri kokhlearnoi implantatsii.

The objective of the present work was to overview the currently available literature publications dealing with the radiodiagnostic techniques applied to evaluate the position of the electrode array used for the purpose of cochlear implantation surgery including both the conventional methods and the recently proposed approaches. It is shown that the intraoperative control guarantees the timely identification of the possible complications and should meet both the safety criteria and the requirements for obtaining high-quality images and intraoperative usability of the surgical instruments being employed. Moreover, the intraoperative monitoring can be exercised under control of fluoroscopy as well as with the use of the portable computed radiography scanners and navigation systems. The postoperative monitoring is carried out with the use of transorbital X ray visualization, multi-slice computed tomography, cone beam computed tomography, and digital tomosynthesis. Each of the listed methods has specific advantages and disadvantages, but there is yet neither a universally recognized systematic approach to the assessment of their effectiveness nor the generally acceptable criteria for the evaluation of the image quality.

[The psychogenic hearing disorders in the children and adolescents]. / Psikhogennoe narushenie slukha u detei i podrostkov.

The psychogenic loss of hearing is characterized by its impairment in the absence of anatomically and physiologically significant changes. These disorders are poorly represented in the scientific literature in comparison with the organic lesions. They are especially frequently overlooked in the children and adolescents. The objective of the present review was to analyze the literature publications concerning this problem and to report two clinical observations of the pathology in question. It is concluded that the clinically significant discrepancy between the audiological symptoms and the results obtained by the objective methods for hearing evaluation should be interpreted with great caution and raise the suspicion of the disease. The diagnosis and the identification of the involved psychogenic factors are of utmost importance for the success of the treatment.

[Distribution in early mouse embryos of foreign mtDNA transmitted along the paternal lineage].

Transmission of foreign mtDNA along the paternal lineage founded by male mice (F0), and distribution of that mtDNA in their progeny at early stages of prenatal development were studied. Transmitochondrial males of F0 obtained after injection of human mitochondria into mouse zygotes has been shown to transmit foreign mtDNA to subsequent generations. Individual peculiarities among the males studied, concerning transmission of foreign mtDNA to the progeny, are likely to exist. Besides, the distribution of human mtDNA among blastomeres of transmitochondrial embryos under study differed from that observed in previous investogation of its inheritance along the maternal lineage.

[Prospects of Levofloxacin Use in Therapy of Patients with Bronchopulmonary Diseases or Skin and Soft Tissue Pyo-Inflammatory Lesions].

The results of the clinico-microbiological investigation of the levofloxacin efficacy in the treatment of 38 patients with respiratory infections or various pyo-inflammatory lesions are presented. The positive results were stated in 29 (76.3%) patients. No adverse reactions were observed.

[Treatment approaches for bronchopulmonary infection in myasthenia gravis patients].

Nineteen patients with bronchopulmonary infection and myasthenia gravis were enrolled in the study. The microbiological analysis of the specimens of phlegm and bronchial secretion revealed both grampositive and gramnegative bacteria. All the isolates were susceptible to the antibiotic used (cefoperazone/sulbactam). Intravenous immunoglobulins (IvIgs) were used to increase the treatment efficacy, to opsonize the infection foci and to decrease the hospitalization terms. The antibiotic therapy and simultaneous use of intravenous immunoglobulins provided higher clinical efficacy in 16 out of 19 patients (84.2%).

[Neuropathy in n-hexane poisoning]. / Neiropatiya pri otravlenii n-geksanom.

N-Hexane is a solvent widely used in manufacturing as a cleaner, degreaser and component of rubber cement. Chronic exposure to n-hexane either through contact with unprotected skin or inhalation can lead to the development of clinical symptoms and electrophysiological changes similar to those of inflammatory demyelinating polyneuropathy which requires careful differential diagnosis. This article presents three cases of severe predominantly motor polyneuropathy with demyelinating features in 15- and 16-year-old adolescents. The results of laboratory tests were within normal limits; electroneuromyography revealed symmetrical involvement of sensory and motor fibers of the nerves of the legs and arms with a decrease in the speed of propagation of excitation and conduction blocks. Sural nerve biopsy revealed intraneural and perineural swelling without any signs of inflammation or fibrosis confirming the genesis of the neuropathy. Despite a relatively favorable prognosis there is no specific therapy for hexane poisoning and the recovery period can last up to several years.

Barium sulphate microparticles are taken up by three different cell types: HeLa, THP-1, and hMSC.

Cytotoxicity and cellular uptake of spherical barium sulphate microparticles (diameter 1 µm) were studied with three different cell lines, i.e. THP-1 cells (monocytes; model for a phagocytosing cell line), HeLa cells (epithelial cells; model for a non-phagocytosing cell line), and human mesenchymal stem cells (hMSCs; model for non-phagocytosing primary cells). Barium sulphate is a chemically and biologically inert solid which allows to distinguish two different processes, e.g. the particle uptake and potential adverse biological reactions. Barium sulphate microparticles were surface-coated by carboxymethylcellulose (CMC) which gave the particles a negative charge. Fluorescence was added by conjugating 6-aminofluorescein to CMC. The cytotoxicity of these microparticles was studied by the MTT test and a live/dead assay. The uptake was visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The particle uptake mechanism was quantified by flow cytometry with different endocytosis inhibitors in THP-1 and HeLa cells. The microparticles were easily taken up by all cell types, mostly by phagocytosis and micropinocytosis, within a few hours. STATEMENT OF SIGNIFICANCE: The interaction of particles and cells is of primary importance in nanomedicine, drug delivery, and nanotoxicology. It is commonly assumed that cells take up only nanoparticles unless they are able to phagocytosis. Here, we demonstrate with chemically and biologically inert microparticles of barium sulphate that even non-phagocytosing cells like HeLa and hMSCs take up microparticles to a considerable degree. This has considerable implication in biomaterials science, e.g. in case of abrasive debris and particulate degradation products from implants like endoprostheses.

Tissue engineering at the dentin-pulp interface using human treated dentin scaffolds conditioned with DMP1 or BMP2 plasmid DNA-carrying calcium phosphate nanoparticles.

Hard dental tissue pathologies, such as caries, are conventionally managed through replacement by tooth-colored inert biomaterials. Tissue engineering provides novel treatment approaches to regenerate lost dental tissues based on bioactive materials and/or signaling molecules. While regeneration in the form of reparative dentin (osteo-dentin) is feasible, the recapitulation of the tubular microstructure of ortho-dentin and its special features is sidelined. This study characterized in vitro, and in vivo human EDTA-treated, freeze-dried dentin matrices (HTFD scaffolds) conditioned with calcium phosphate nanoparticles (NPs) bearing plasmids encoding dentinogenesis-inducing factors (pBMP2/NPs or pDMP1/NPs). The uptake and transfection efficiency of the synthesized NPs on dental pulp stem cells (DPSCs) increased in a concentration- and time-dependent manner, as evaluated qualitatively by confocal laser microscopy and transmission electron microscopy, and quantitatively by flow cytometry, while, in parallel, cell viability decreased. HTFD scaffolds conditioned with the optimal transfectability-to-viability concentration at 4 µg Ca/mL of each of the pBMP2/NPs or pDMP1/NPs preserved high levels of cell viability, evidenced by live/dead staining in vitro and caused no adverse reactions after implantation on C57BL6 mice in vivo. HTFD/NPs constructs induced rapid and pronounced odontogenic shift of the DPSCs, as evidenced by relevant gene expression patterns of RunX2, ALP, BGLAP, BMP-2, DMP-1, DSPP by real-time PCR, and acquirement of polarized meta-mitotic phenotype with cellular protrusions entering the dentinal tubules as visualized by scanning electron microscopy. Taken together, HTFD/NPs constitute a promising tool for customized reconstruction of the ortho-dentin/odontoblastic layer barrier and preservation of pulp vitality. STATEMENT OF SIGNIFICANCE: In clinical dentistry, the most common therapeutic approach for the reconstruction of hard dental tissue defects is the replacement by resin-based restorative materials. Even modern bioactive materials focus on reparative dentinogenesis, leading to amorphous dentin-bridge formation in proximity to the pulp. Therefore, the natural microarchitecture of tubular ortho-dentin is not recapitulated, and the sensory and defensive role of odontoblasts is sidelined. This study approaches the reconstruction at the dentin-pulp interface using a construct of human treated dentin (HTFD) scaffold and plasmid-carrying nanoparticles (NPs) encoding dentinogenic factors (DMP-1 or BMP-2) with excellent in vitro and in vivo properties. As a future perspective, the HTFD/NPs constructs could act as bio-fillings for personalized reconstruction of the dentin-pulp interface.

Covalent coupling of HIV-1 glycoprotein trimers to biodegradable calcium phosphate nanoparticles via genetically encoded aldehyde-tags.

The usage of antigen-functionalized nanoparticles has become a major focus in the field of experimental HIV-1 vaccine research during the last decade. Various molecular mechanisms to couple native-like trimers of the HIV-1 envelope protein (Env) onto nanoparticle surfaces have been reported, but many come with disadvantages regarding the coupling efficiency and stability. In this study, a short amino acid sequence ("aldehyde-tag") was introduced at the C-terminus of a conformationally stabilized native-like Env. The post-translational conversion of a tag-associated cysteine to formylglycine creates a site-specific aldehyde group without alteration of the Env antigenicity. This aldehyde group was further utilized for bioconjugation of Env trimers. We demonstrated that the low acidic environment necessary for this bioconjugation is not affecting the trimer conformation. Furthermore, we developed a two-step coupling method for pH-sensitive nanoparticles. To this end, we conjugated aldehyde-tagged Env with Propargyl-PEG3-aminooxy linker (oxime ligation; Step-one) and coupled these conjugates by copper-catalyzed azide-alkyne cycloaddition (Click reaction; Step-two) to calcium phosphate nanoparticles (CaPs) functionalized with terminal azide groups. CaPs displaying orthogonally arranged Env trimers on their surface (o-CaPs) were superior in activation of Env-specific B-cells (in vitro) and induction of Env-specific antibody responses (in vivo) compared to CaPs with Env trimers coupled in a randomly oriented manner. Taken together, we present a reliable method for the site-specific, covalent coupling of HIV-1 Env native-like trimers to the surface of nanoparticle delivery systems. This method can be broadly applied for functionalization of nanoparticle platforms with conformationally stabilized candidate antigens for both vaccination and diagnostic approaches. STATEMENT OF SIGNIFICANCE: During the last decade antigen-functionalized nanoparticles have become a major focus in the field of experimental HIV-1 vaccines. Rational design led to the production of conformationally stabilized HIV-1 envelope protein (Env) trimers - the only target for the humoral immune system. Various molecular mechanisms to couple Env trimers onto nanoparticle surfaces have been reported, but many come with disadvantages regarding the coupling efficiency and stability. In this paper, we describe a highly selective bio-conjugation of Env trimers to the surface of medically relevant calcium phosphate nanoparticles. This method maintains the native-like protein conformation and has a broad potential application in functionalization of nanoparticle platforms with stabilized candidate antigens (including stabilized spike proteins of coronaviruses) for both vaccination and diagnostic approaches.

CHEK2 I157T and colorectal cancer in Bulgaria.

PURPOSE: Germline variants of the CHEK2 gene have been shown to act as low-penetrance cancer susceptibility alleles for a wide range of human malignancies. CHEK2 I157T has particularly been linked to colorectal cancer (CRC) risk. We aimed at establishing the population frequency and contribution of this variant to colorectal carcinogenesis in Bulgaria. METHODS: We have genotyped 802 population controls and 343 CRC patients from Bulgaria for the CHEK2 I157T variant. RESULTS: Heterozygous were 9 of 343 patients (2.62%, odds ratio/OR=1.0, 95% confidence interval/CI = 0.42 - 2.33, p=0.99% and 21 of 802 controls (2.62%). Higher frequencies were found among patients with multiple polyposis (2/40, 5%, p=0.28) and the rarer mucinous histology (1/11, 9.09%, p= 0.26). CONCLUSION: We conclude that CHEK2 I157T is not relevant for CRC risk in Bulgaria, but studies on a larger scale might help evaluate its possible significance in respect to disease characteristics.

A Novel Nanoconjugate of Landomycin A with C60 Fullerene for Cancer Targeted Therapy: In Vitro Studies.

INTRODUCTION: Landomycins are a subgroup of angucycline antibiotics that are produced by Streptomyces bacteria and possess strong antineoplastic potential. Literature data suggest that enhancement of the therapeutic activity of this drug may be achieved by means of creating specific drug delivery systems. Here we propose to adopt C60 fullerene as flexible and stable nanocarrier for landomycin delivery into tumor cells. METHODS: The methods of molecular modelling, dynamic light scattering and Fourier transform infrared spectroscopy were used to study the assembly of C60 fullerene and the anticancer drug Landomycin A (LA) in aqueous solution. Cytotoxic activity of this nanocomplex was studied in vitro towards two cancer cell lines in comparison to human mesenchymal stem cells (hMSCs) using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test and a live/dead assay. The morphology of the cells incubated with fullerene-drug nanoparticles and their uptake into target cells were studied by scanning electron microscopy and fluorescence light microscopy. RESULTS: The viability of primary cells (hMSCs, as a model for healthy cells) and cancer cell lines (human osteosarcoma cells, MG-63, and mouse mammary cells, 4T1, as models for cancer cells) was studied after incubation with water-soluble C60 fullerenes, LA and the mixture C60 + LA. The C60 + LA nanocomplex in contrast to LA alone showed higher toxicity towards cancer cells and lower toxicity towards normal cells, whereas the water-soluble C60 fullerenes at the same concentration were not toxic for the cells. CONCLUSIONS: The obtained physico-chemical data indicate a complexation between the two compounds, leading to the formation of a C60 + LA nanocomposite. It was concluded that immobilization of LA on C60 fullerene enhances selectivity of action of this anticancer drug in vitro, indicating on possibility of further preclinical studies of novel C60 + LA nanocomposites on animal tumor models.

[Distribution of foreign mitochondrial DNA during the first splittings of the transmitochondrial mouse embryos].

Distribution of human mitochondrial DNA (mtDNA) among separate murine blastomeres was analyzed during the splitting of embryos in which the suspension of human mitochondria had been injected at the one- or two-cell stage. Human mtDNA was detected by PCR with species specific primers. The total amount of the two- and four-cell murine embryos analyzed in the study was 339. In all embryos examined the copies of human mitochondrial genome were revealed along with murine mtDNA, which indicated the phenomenon of an artificially modeled heteroplasmy. The foreign mtDNA was not ubiquitous among the blastomeres of transmitochondrial embryos. Mathematical analysis of the results showed that in the period between the injection of human mitochondria and the subsequent splitting no equal distribution of the human mtDNA occurred in the cytoplasm. These results also point at the presence of more than 2-3 segregation units of mtDNA in the entire pool of mitochondria (about 5 x 10(2)) introduced into an embryo by microinjection.

A systematic electron microscopic study on the uptake of barium sulphate nano-, submicro-, microparticles by bone marrow-derived phagocytosing cells.

Nanoparticles can act as transporters for synthetic molecules and biomolecules into cells, also in immunology. Antigen-presenting cells like dendritic cells are important targets for immunotherapy in nanomedicine. Therefore, we have used primary murine bone marrow-derived phagocytosing cells (bmPCs), i.e. dendritic cells and macrophages, to study their interaction with spherical barium sulphate particles of different size (40 nm, 420 nm, and 1 µm) and to follow their uptake pathway. Barium sulphate is chemically and biologically inert (no dissolution, no catalytic effects), i.e. we can separate the particle uptake effect from potential biological reactions. The colloidal stabilization of the nanoparticles was achieved by a layer of carboxymethylcellulose (CMC) which is biologically inert and gives the particles a negative zeta potential (i.e. charge). The particles were made fluorescent by conjugating 6-aminofluoresceine to CMC. Their uptake was visualized by flow cytometry, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and correlative light and electron microscopy (CLEM). Barium sulphate particles of all sizes were readily taken up by dendritic cells and even more by macrophages, with the uptake increasing with time and particle concentration. They were mainly localized inside phagosomes, heterophagosomes, and in the case of nanoparticles also in the nearby cytosol. No particles were found in the nucleus. In nanomedicine, inorganic nanoparticles from the nanometer to the micrometer size are therefore well suited as transporters of biomolecules, including antigens, into dendritic cells and macrophages. The presented model system may also serve to describe the aseptic loosening of endoprostheses caused by abrasive wear of inert particles and the subsequent cell reaction, a question which relates to the field of nanotoxicology. STATEMENT OF SIGNIFICANCE: The interaction of particles and cells is at the heart of nanomedicine and nanotoxicology, including abrasive wear from endoprostheses. It also comprises the immunological reaction to different kinds of nanomaterials, triggered by an immune response, e.g. by antigen-presenting cells. However, it is often difficult to separate the particle effect from a chemical or biochemical reaction to particles or their cargo. We show how chemically inert barium sulphate particles with three different sizes (nano, sub-micro, and micro) interact with relevant immune cells (primary dendritic cells and macrophages). Particles of all three sizes are readily taken up into both cell types by phagocytosis, but the uptake by macrophages is significantly more prominent than that by dendritic cells. The cells take up particles until they are virtually stuffed, but without direct adverse effect. The uptake increases with time and particle concentration. Thus, we have an ideal model system to follow particles into and inside cells without the side effect of a chemical particle effect, e.g. by degradation or ion release.

[Prediction of respiratory complications after radical surgeries for non-small cell carcinoma of the lung].

A predictive role of volume-velocity (VV) indices of ventilation in prognosis of respiratory complications after radical surgeries for non-small cell carcinoma of the lung was evaluated. It is demonstrated that decreased VV indices of ventilation before surgery directly correlate with a respiratory complication rate after surgery. New methods of diagnosis of ventilation disorders and of monitoring are regarded as promising.

[RECOGNITION OF ADULTS EMOTIONAL STATE OF TYPICALLY DEVELOPING CHILDREN AND CHILDREN WITH AUTISM SPECTRUM DISORDERS].

The goal of the study was the definition of adult's possibilities of recognition the emotional state of typically developing (TD) and children with autism spectrum disorders (ASD), by facial expression, vocalizations and speech signals. Participants in the study were children with ASD (F 84.0 according to ICD-10), aged 5-16 years (n = 25) and typically developing (TD) children aged 4-7 years (n = 60). The analysis of child behavior, vocalizations and speech was performed for the purpose of stimulus selection. The peculiarities of emotion state recognition of TD children and ASD children by adults (n = 514) were revealed. It is shown that the emotional states of ASD children are better recognized by the features of vocalizations and speech than by facial expression. This finding is promising in terms of development of children with methods for assessing the characteristics of their voices, and to create an automatic speech recognition system for the purpose of teaching children with atypical development.

Interaction of C60 fullerene complexed to doxorubicin with model bilipid membranes and its uptake by HeLa cells.

With an aim to elucidate the effects of C60 fullerene complexed with antibiotic doxorubicin (Dox) on model bilipid membranes (BLM), the investigation of the electrical properties of BLM under the action of Dox and C60 fullerene, and of their complex, C60+Dox,was performed. The complex as well as its components exert a clearly detectable influence on BLM, which is concentration-dependent and also depends on phospholipid composition. The mechanism of this effect originates either from intermolecular interaction of the drug with fatty-acid residues of phospholipids, or from membranotropic effects of the drug-induced lipid peroxidation, or from the sum of these two effects. By fluorescence microscopy the entering of C60 + Dox complex into HeLa cells was directly shown.