[Impact of mutations in nucleoprotein on replication of influenza virus A/Hong Kong/1/68/162/35 reassortants at different temperatures].

The nucleoprotein (NP) of influenza virus is a multifunctional RNA binding protein. The role of NP in the adaptation of influenza viruses to a host has been experimentally proved. Ambiguous data are available on the role of nucleoprotein in the attenuation of influenza A viruses, which is characterized by ability to replicate at low temperature (26°C) and inability to replicate at high temperature (39°C). Influenza virus donor strain A/Hong Kong/1/68/162/35 (H3N2), adapted to growth at low temperature, differs from the wild type virus by 14 amino acid mutations in the internal and non-structural proteins. Two mutations occurred in the NP: Gly102Arg and Glu292Gly. We have obtained viruses with point reverse-mutations in these positions and compared their replication at different temperatures by measuring infectious activity in chicken embryos. It has been shown that reverse mutation Gly292Glu in the NP reduced virus ability to replicate at low temperature, the introduction of the second reverse mutation Arg102Gly completely abolished virus cold adaptation.

Combined nitrogen, hexane, and benzene adsorption characterization of pores and surfaces of lyophobic mesoporous silicas.

For lyophobic porous surfaces, structural analysis by vapor adsorption is complicated due to weak adsorbate-adsorbent interactions and limited wetting of the pores (nonzero contact angles). To investigate further, adsorption isotherms of three distinct adsorbates (nitrogen - 77 K, n-hexane and benzene - 298 K) were studied for SBA-15 ordered mesoporous silica where the surface was functionalized with lyophobic perfluoroalkyl groups (C6F13 termini). The results demonstrated a clear advantage of the combined use of the adsorption isotherms of less surface sensitive (nitrogen) and more surface sensitive (hydrocarbons) adsorbates. The adsorption of nitrogen provided basic structural characteristics like surface area, pore volume, and pore size distribution, while the isotherms of benzene and n-hexane were used to characterize wetting (contact angles) and surface energy of the C6F13 surfaces within the pores. For the first time, the statistical film thickness for nitrogen, benzene, and n-hexane are being reported for the adsorption on fluorinated surfaces, thereby providing critical data for the pore size and the contact angle determination of the lyophobic materials.

First detection of influenza A virus subtypes H1N1 and H3N8 in the Antarctic region: King George Island, 2023.

RELEVANCE: Influenza A virus is characterized by a segmented single-stranded RNA genome. Such organization of the virus genome determines the possibility of reassortment, which can lead to the emergence of new virus variants. The main natural reservoir of most influenza A virus subtypes are wild waterfowl. Seasonal migrations gather waterfowl from all major migration routes to nesting areas near the northern and southern polar circles. This makes intercontinental spread of influenza A viruses possible. Objective ‒ to conduct molecular genetic monitoring and study the phylogenetic relationships of influenza A virus variants circulating in Antarctica in 2023. MATERIALS AND METHODS: We studied 84 samples of biological material obtained from birds and marine mammals in April‒May 2023 in coastal areas of Antarctica. For 3 samples, sequencing was performed on the Miseq, Illumina platform and phylogenetic analysis of the obtained nucleotide sequences of the influenza A virus genomes was performed. RESULTS: The circulation of avian influenza virus in the Antarctic region was confirmed. Heterogeneity of the pool of circulating variants of the influenza A virus (H3N8, H1N1) was revealed. Full-length genomes of the avian influenza virus were sequenced and posted in the GISAID database (EPI_ISL_19032103, 19174530, 19174467). CONCLUSION: The study of the genetic diversity of influenza A viruses circulating in the polar regions of the Earth and the identification of the conditions for the emergence of new genetic variants is a relevant task for the development of measures to prevent biological threats.

[The assessment of mechanical heart valves stenosis in adults after aortic valve replacement: the advantage of full-flow design of mechanical valve].

The analysis of transprosthetic hemodynamics in adults after aortic valve replacement in the Bakoulev Center for Cardiovascular Surgery in 2007-2010 demonstrated the hemodynamic advantage of the concept of new full-flow mechanical aortic valve prosthesis "CorBeat". Having the same size of internal orifice and tissue annulus diameters, the values of transprosthetic parameters (peak and mean gradients, blood flow velocities) through "CorBeat" were close to physiological values of transvalvular native aortic parameters and had a tendency to be not dependent on the size of prosthesis (p = 0.63). In the article for the first time a morphometric database of geometric values of internal orifice area of normal native aortic valves in adults was used taking into account both the gender and the body surface area's of a patient. There was also used the standardized prosthesis size Z-score which represents the number of SDs by which the internal prosthesis area differs from the mean normal native aortic valve area for the patient's body surface area. The article emphasizes the need of the personal selection of the size and the type of prosthesis for any patient as well as the need for new design development of prosthetic heart valves.

[Progress in cardiovascular surgery: new analytical, experimental, and technological approaches].

Blood flow in heart and main vessels is a self-organizing eddy flow described by Kiknadze-Krasnov's non-stationary hydrodynamic equations. Their exact solutions are applicable to simulation of blood circulation in normal and pathological conditions, quantitative evaluation of efficiency of surgical treatment of cardiovascular diseases, and designing implantable devices for cardiovascular surgery to support physiological blood flow structure. An essentially new all-flow three-leaflet CorBit artificial heart valve from pyrolyitic carbon has been proposed to maintain physiological blood flow with minimal regurgitation and transvalvular pressure gradient. The CorBit valve allows to normalize hemodynamic parameters soon after implantation. Also, manufacture is underway of a wide range of original stented and stentless bioprostheses of heart valves and valve-containing BioLab conduits from allogenic and xenogenic biological tissues. BioLab bioprostheses are currently widely used to treat complicated congenital and acquired forms of cardiopathology.

[The electrode for selective nociceptive stimulation: use experience and prospect for application in nociception studies in a human].

Electrode for selective nociception specific stimulation was described by H. Kaube et al. in 2000. The aim of this work was to test this electrode in assessment of nociceptive reactions of the segmental and suprasegmental levels. The method of nociception specific blink reflex based on the use of this electrode was applied in a modified variant for examination of patients with a tension type headache. A decrease in the nociceptive reflex threshold was revealed in patients with episodic headaches (as compared to healthy volunteers). Both the reflex and pain thresholds were decreased in patients with a chronic headache. These results indicate the sensitization of nociceptive structures in patients with a headache. Cerebral evoked potentials elicited by skin stimulation of face and extremities with Kaube electrode were studied in healthy volunteers. The dominance of the late components (100-300 ms) considered to be of nociceptive origin was revealed in the pattern of evoked potentials. Thus, the electrode assures a high degree of selectivity of the pain-specific stimulation. Its adaptation for assessment of various nociceptive reactions can perfect the neurophysiological methods of nociception studies.

[Preliminary results of radical surgery and radiotherapy of locally advanced prostate cancer (basal PSA >50 ng/ml)].

Despite recent progress made in early diagnosis of prostate cancer, medical advice is sought mostly at locally advanced stage. Both surgery and radiotherapy (distant or contact) are used. Yet, such methods have limited application, namely, in patients with basal level of prostate-specific antigen (PSA) under 50 ng/ml, without distant metastases. Even in those with excess of that value and without apparent distant metastases, i.e. cases at high risk of tumor process generalization, local treatment may be carried out on a limited scale. Tentative data are discussed on the results of combined treatment of such a group of patients as, compared with hormone therapy.

GENETIC AND ANTIGENIC CHARACTERISTICS OF RESPIRATORY SYNCYTIAL VIRUS STRAINS ISOLATED IN ST. PETERSBURG IN 2013-2016.

Antigenic and genetic characteristics of Russian RSV isolates are presented for the first time. Of the 69 strains isolated in St. Petersburg, 93% belonged to the RSV-A antigenic group. The antigenic variations in the F-protein RSV were analyzed using a panel from 6 monoclonal antibodies by the method of micro-cultural ELISA. Depending on the decrease in the effectiveness of interaction with monoclonal antibodies (relative to the reference strain Long), RSV-A isolates were divided into 4 antigenic subgroups. The results of 24 isolates sequencing showed that more than 60% of them had substitutions in significant F-protein sites compared to the ON67-1210A reference strain of the current RSV genotype ON1/GA2. The most variable were the signal peptide and antigenic site II. When comparing the results of ELISA and sequencing, it was not possible to identify any specific key substitutions in the amino acid sequence of the F-protein that affect the interaction of the virus with antibodies. The nucleotide sequence of the F-gene from 19 of the 24 characterized isolates was close to that of ON67-1210A reference virus and was significantly different from RSV-A Long and A2 viruses. A separate group consisted of 5 strains, in which the F-protein structure was approximated to RSV Long.

Emergency cesarean section in a patient with Fontan circulation using an indwelling epidural catheter.

Management of parturients with a history of Fontan procedure requires careful monitoring of cardiovascular parameters and anticipation of potential complications. We describe potential pitfalls in a parturient with atriopulmonary Fontan circulation, who received epidural analgesia for labor and who later required emergency cesarean section. Low-dose local anesthetic in combination with meperidine provided excellent perioperative epidural analgesia and cardiovascular stability. Epidural analgesia during labor offered optimal pain relief and facilitated conversion to surgical anesthesia for an emergency cesarean section.

[Uterine pathomorphology in abruptio placentae].

15 uteri removed surgically because of abruptio placentae (AP) were studied morphologically. AP develops as a process due to a combination of maternal (endometritis, gestosis, adenomyosis), placental (pathology of microvilli, hypercoagulation of venous blood) and hemorheological (thrombosis of placental bed veins, partial blockade of venous circulation) factors. These factors result in the formation of retroplacental hematoma and progressing intrauterine fetal hypoxia.

[Comparative characteristics of pathogenesis of chronic gastroduodenetic pathology in servicemen from different professional groups].

345 servicemen from Air Forces were being examined. That group consisted of 105 servicemen working in deepened special constructions (DSC), 62 from flying staff and 178 from compact sampling. Statistical processing of questionnaire results and the data of gastroenterological examination have shown that main well-known ethiopathogenetic factors influence negatively during the course of chronic gastroduodenetic pathology in servicemen. By the way the main element of pathogenesis in DSC personnel is Helicobacter pylori invasion, and in flying staff is an alimentary factor and unhealthy habits.

[The importance of specialised pathology service in diagnosis of ascending infection of the reproductive system in pregnant women].

Practical results of screening cytological diagnosis of urogenital infections in pregnant women and mass pathomorphological investigations of newborn placentas performed by bureaus of pathology in Leningrad region and Cheboksary city are reviewed. Important place of the ascending bacterial infection in the structure of reproductive mortality is emphasized.

Elution behavior of polyethylene in polar mobile phases on a non-polar sorbent.

Linear polyethylene standards in the range of 1-500 kg/mol, dissolved in 1,2,4-trichlorobenzene, were injected into a column packed with oligo(dimethylsiloxane) modified silica gel. Fifteen polar solvents (cyclohexanone, cyclohexylacetate, cyclohexanol, nonylalcohol, dimethylformamide, dimethyl sulfoxide, ethylene- and diethylene glycol monobutyl ether, benzylalcohol, hexylacetate, bis(2-ethyl-hexyl)phthalate, N,N-dimethylacetamide, propylene carbonate, dipropylene glycol and N-methyl-pyrrolidone) were evaluated as mobile phases. Depending on the type of mobile phase evaluated, different elution behaviors are observed for polyethylene: (1) polyethylene was eluted in the size exclusion mode, (2) polyethylene was eluted together with the sample solvent peak at constant elution volume, (3) polyethylene was partially or fully retained on the column. The retained polymer was easily removed from the column by injecting a small volume of trichlorobenzene. The use of ethylene glycol monobutyl ether as the mobile phase enabled separation of the polyethylene from polypropylene. In this case polypropylene is eluted in the size exclusion mode, while polyethylene is eluted at a constant elution volume or remains in the column.

Adsorption study of alkyl-silicas and methylsiloxy-silicas.

We report the synthesis and adsorption study of the lyophobic porous silicas. Four adsorbents were prepared and tested: (1) octyl-silica, (2) hexadecyl-silica, (3) bis(trimethylsiloxy)-silica, and (4) oligo(dimethylsiloxane)-silica. Octyl- and hexadecyl-silicas were prepared via the reaction of silica with (CH3)2NSi(CH3)2CnH(2n+1) (n=8 and 16), the reactions were carried under the optimized conditions yielding high bonding densities of alkyl groups approximately 2.9-3.0 groups/nm2 and highly uniform non-polar adsorbents. Bis(trimethylsiloxy)-silica was prepared via the reaction silica with ClSi(CH3)2(CH2)10Si(CH3)[OSi(CH3)3]2. Oligo(dimethylsiloxane)-silica was prepared via the reaction of silica with ClSi(CH3)2-[OSi(CH3)2]2-Cl. Adsorption of small organic compounds (n-alkanes, alkylbenzene, benzene, diethyl ether) was investigated using two methods, classical static adsorption and gas chromatography. Thermodynamic parameters (heat, Gibbs energy, and entropy) of the adsorption of organic compounds were studied as a function of the nature of adsorbate and of the nature of the bonded layer as well. The results obtained suggest penetration of the adsorbate molecules into the bonded layer and the importance of this process in the retention mechanism in gas chromatography. Energy of the dispersion interactions with the surface decreases in the following order: n-C16H33(CH3)2Si- > n-C8H17(CH3)2Si- > [(CH3)3SiO]2Si(CH3)-(CH2)10(CH3)2Si- > -[[(CH3)2SiO]2]x-(CH3)2Si-. Energy of the electrostatic and hydrogen bonding interactions with the surface, as assessed from the adsorption of benzene and diethyl ether molecules, decreases in the opposite direction, indicating that alkyl-silicas are less polar adsorbents than methylsiloxy-silicas.

[The accelerated method of paraffin embedding in pathohistological practice]. / Uskorennaia metodika parafinovoi zalivki v patogistologicheskoi praktike.

An accelerated method of paraffin embedding of placentas in pathohistological practice is suggested allowing to get micropreparations stained with hematoxylin and eosin and other methods from 500 500 and more blocks 4-5 hours after cutting. This enables to analyze material from groups of risk among children born alive and rapid informing neonatologists and pediatricians. The method is based on rejection of formaldehyde fixation (this excludes a toxic effect on the personnel). Use of acetone combines fixation and dehydration. The reagents usable for technical reasons make the proposed method cost effective.

[Infantile type of Niemann-Pick disease with developmental defects of the central nervous system]. / Infantil'nyi tip bolezni Nimana-Pika s porokom razvitiia tsentral'noi nervnoi sistemy.

Clinical and morphologic manifestations of a rare disease developing, as a rule, in early life--an infantile variant of Niemann-Pick disease--are illustrated with a fatal case of a 6.5-month-old child. The diagnosis was established histochemically using, in particular, Smith-Dietrich method which provided differential diagnosis with cerebroside lipidosis (Gaucher's disease). In addition to typical enlargement of the liver, spleen and lymph nodes, cerebral and adrenal affection there appeared true porencephalia.

[Study of functional parameters of prosthetic cardiac valves]. / Issledovaniia funktsional'nykh kharakteristik iskusstvennykh klapanov serdtsa.

A set of methods is offered, which enables to examine, with more details, the functional characteristics of the valves and to analyze them comparatively. The thus obtained functional characteristics make it possible to compare the valves and to select the best one prior to implantation. The results of a clinical study of the functioning of a valve, implanted by a new method involving a high-sensitivity solid sensor, are described.

[Occupational hygiene in production and use of multicomponent metal compounds]. / Gigiena truda pri poluchenii i primenenii mnogokompozitsionnykh soedinenii metallow.

The article deals with results obtained in hygienic evaluation of production and application of new monocrystalline compounds based on cesium, sodium, iodine, lead, scandium, fluorine. The evaluation covered work conditions and health state of those engaged into production of monocrystalline compounds, revealed the main occupational hazards. The experiments determined fundamental toxicometric parameters, studied characteristics of general toxic and specific effects induced by lead fluoride and cesium iodine. The results formed basis for sanitary measures, establishment of MACs for 4 monocrystalline compounds in the air of workplace.

[The role of military medical expertise in preserving the mental health of servicemen]. / Rol' voenno-vrachebnoi ékspertizy v sokhranenii psikhicheskogo zdorov'ia voennosluzhashchikh.

The authors examine factors of mental dysadaptation, neurotic disorders' formation and psychopathy criminal reactions in draftees. An emphasis has been made on the clinical and psychological stages of dysadaptation and psycho-dysadaptation cases of pre-nosolologic levels. Some measures of improvement for military-medical panels have been offered.

[The late effects of exposure to lead fluoride]. / Otdalennye éffekty vozdeistviia ftorida svintsa.

Effect of lead fluoride dust on the micronuclear reticulocyte content in the bone marrow was shown. Some functional changes in the testicles and increase in the fetal death rate in exposure to 50 mg/m3 of lead fluoride dust were noted.