Surface waves and crustal structure on Mars.

We detected surface waves from two meteorite impacts on Mars. By measuring group velocity dispersion along the impact-lander path, we obtained a direct constraint on crustal structure away from the InSight lander. The crust north of the equatorial dichotomy had a shear wave velocity of approximately 3.2 kilometers per second in the 5- to 30-kilometer depth range, with little depth variation. This implies a higher crustal density than inferred beneath the lander, suggesting either compositional differences or reduced porosity in the volcanic areas traversed by the surface waves. The lower velocities and the crustal layering observed beneath the landing site down to a 10-kilometer depth are not a global feature. Structural variations revealed by surface waves hold implications for models of the formation and thickness of the martian crust.

Geometry and Segmentation of Cerberus Fossae, Mars: Implications for Marsquake Properties.

The NASA InSight mission to Mars successfully landed on 26 November 2018 in Elysium Planitia. It aims to characterize the seismic activity and aid in the understanding of the internal structure of Mars. We focus on the Cerberus Fossae region, a giant fracture network ∼1,200 km long situated east of the InSight landing site where M ∼3 marsquakes were detected during the past 2 years. It is formed of five main fossae located on the southeast of the Elysium Mons volcanic rise. We perform a detailed mapping of the entire system based on high-resolution satellite images and Digital Elevation Models. The refined cartography reveals a range of morphologies associated with dike activity at depth. Width and throw measurements of the fossae are linearly correlated, suggesting a possible tectonic control on the shapes of the fossae. Widths and throws decrease toward the east, indicating the long-term direction of propagation of the dike-induced graben system. They also give insights into the geometry at depth and how the possible faults and fractures are rooted in the crust. The exceptional preservation of the fossae allows us to detect up to four scales of segmentation, each formed by a similar number of 3-4 segments/subsegments. This generic distribution is comparable to continental faults and fractures on Earth. We anticipate higher stress and potential marsquakes within intersegment zones and at graben tips.

[Comparative study of MDCK and CaCo-2 cell lines for influenza virus isolation].

Study of effectiveness of CaCo-2 cell line for influenza virus isolation was carried out. It was shown that the properties of this cell line strongly depended on the source of its origin and cultivation conditions. The infectious activity of the influenza viruses on CaCo-2 cell line was virtually the same as in the MDCK cell line. The rate of the viral isolation was virtually identical for both cell lines tested, but viruses from post-mortem materials were isolated only in CaCo-2 cell line. In general, the CaCo-2 line is believed to be a valuable cell line for virological research, particularly for influenza virus isolation.

[Molecular-biological properties of the rubella virus strains isolated in St. Petersburg].

In the surveillance of rubella in the northwest region of Russia samples of nasopharyngeal swabs from 37 patients with rubella, which were treated in the 442nd district military hospital named after Z.P. Solovyov in autumn 2007 were screened for the rubella virus using RK-13 cell line, 22 strains of rubella virus were isolated. Gene sequencing of E1 region of rubella virus isolates was carried out. Rubella virus strains isolated in St. Petersburg during the 2007 outbreak belonged to rubella virus genotype 1E. The morphogenesis of RK-13 cells with formation of replication complexes and enveloped virions of rubella virus was shown.

[Evolutionary variability of influenza B viruses in Russian Federation in 2005-2012].

Specific traits of influenza B viruses circulation in Russia and worldwide in 2005-2012 were studied and the amount of influenza B viruses in the whole population of influenza viruses isolated in Russia was estimated. The trend toward antigenic drift for both Victoria and Yamagata lineages was characterized. The genetic analysis revealed amino acid changes that influenced the antigenic properties of the viruses. The match of the epidemic isolates and vaccine strains was corroborated.

[Development of influenza surveillance in Russia in the system of the WHO national influenza center].

Analysis of development influenza activity season 2010-2011 is presented. Significant participation of influenza A(H1N1)pdm09 virus and influenza B of Victoria lineage virus in the epidemic morbidity structure with minor participation ofA(H3N2) virus was revealed. The influenza viruses isolated in Russia according to antigenic properties were similar to the strains included in the vaccine composition. Drift variants of influenza A(H1N1)pdm09 viruses isolated in Astrakhan and St.-Petersburg were recognized using WHO CC in London as representatives of three new genetic groups.

[Analysis of pandemic influenza in Russia as a part of the global process based on data of an influenza monitoring reference center].

AIM: Characterization of features of influenza pandemic development in Russia in relation to global process. MATERIALS AND METHODS: Pandemic monitoring was performed by using results of integrative analysis of laboratory diagnostic and population morbidity data from 49 supporting bases of Federal center of influenza from various cities in Russian Federation. Isolation of influenza virus was carried out in MDCK cells and chicken embryos under BSL-3 conditions. Reference virus A/California/07/09 obtained from CDC (Atlanta, USA) and antisera against this strain contained in WHO kit were used for antigenic analysis; rat antisera, new monoclonal antibodies against pandemic influenza virus developed by Research institute of influenza were also used. RESULTS: Based on PCR monitoring during epidemic peak, rate of pandemic influenza identification reached 45-49% of examined patients. About 53% of lethal cases of respiratory infections were caused by pandemic influenza virus, while predominately young people died from pneumonia and acute respiratory distress syndrome. Russian isolates generally were antigenically and genetically similar to the parent pandemic strain--influenza virusA/California/07/09, but contained S203T substitution in hemagglutinin. A number of strains contained D222G mutation that is responsible for the expansion of substrate specificity, as well as strain specific substitutions in hemagglutinin and neuraminidase molecules. The investigated isolates were resistant to remantadin, but sensitive to oseltamivir. CONCLUSION: Due to the formation of population immunity after the end of the first pandemic wave new drift variants of the virus capable of overcoming this formed immunity should be expected that apparently will require the correction of vaccine composition for the 2011 - 2012 season.

[Pandemic influenza 2009 in Russia. Characteristics of the isolation and biological properties of viruses].

Research Institute of Influenza, Ministry of Health and Social Development of Russia, Saint Petersburg The characteristics of the isolation of pandemic influenza A(H1N1)v viruses were studied on chick embryos (CE) and MDCK cell culture. The materials (nasal swabs and autopsies) were collected in different regions Russia in the period from 20 July to 30 December 2009. The paper gives the data of the antigenic analysis of isolates, their capacity to multiply in different species-specific and tissue cell cultures. The viruses isolated on CE were shown to have higher hemagglutination titers and to be more stable. Isolation from the autopsies was effective only on CE. All the test cell lines other than MDCK were insensitive to the isolated pandemic influenza strains. The antigenic analysis showed no significant antigenic drift of the viruses isolated during the first wave of the pandemic in the Russian Federation.

[The 2009 pandemic influenza in Russia. I. Diagnosis and molecular biological characteristics of the virus].

The analysis of 1558 clinical samples revealed influenza virus A(H1N1v) RNA in 339 patients with influenza and 163 fatal cases,which was made in May to December 2009. Data on the antigenic properties of more than 250 of pandemic virus strains isolated at the Research Institute of Influenza and the molecular genetic characteristics of 31 strains are presented. All the test isolates were found to have the S203 substitution in hemagglutinin, which was characteristic of one of 5 minor genome A(H1N1v) virus variants found in the United States and Mexico in 2009. All the test strains contain the S31N substitution in the M2 protein, which determines viral resistance to adamantine, and have no H275Y substitution in neuraminidase, which determines oseltamivir resistance. The substitution of amino acid residue of Asp to Gly at position 222 of HA was found in 8 (73%) of 11 isolates from postmortem lung and trachea samples and in 2 (10%) of 20 isolates from nasopharyngeal swabs. The determination of the pathogenic role of this substitution calls for further investigations.

[Comparative study of the differential susceptibility of different cell lines to pandemic H1N1v influenza viruses and avian influenza, swine influenza, and human influenza viruses].

The proliferation characteristics of influenza viruses of different origin were tested in various human and animal cell cultures. Pandemic H1N1v influenza and swine influenza viruses were shown to have a low infectious activity in virtually all the test lines. In spite of this, the replication of this group of viruses may be detected by de novo NP synthesis. These viruses are able to activate programmed cell death. Moreover, a low inoculative virus dose exerts a stimulating effect on cell proliferation in both suspension and monolayer cell lines.

[Etiological characteristics of the influenza epidemics of 2006-2009 in the Russian Federation (according to the data of the Research Institute of Influenza, North-Western Branch, Russian Academy of Medical Sciences)].

The basic trends in the evolution of influenza A and B in the Russian Federation during the epidemic seasons of 2006-2009 were studied on the basis of an antigenic analysis of 1774 Influenza isolated at the Research Institute of Influenza (RII), North-Western Branch, Russian Academy of Medical Sciences, and sent from resting bases (the regional centers of the Russian Inspectorate for the Protection of Consumer Rights and Human Welfare, which collaborate with the RII). Although the trends in the substitution of representative strains generally coincide with the world patterns, the authors revealed some specific features of the antigenic drift of influenza viruses in the Russian Federation and regional varieties. Data on some biological properties and those of the antigenic analysis of the first pandemic influenza A(H1NI)v strains isolated at the RII from Saint Petersburg patients in July-August 2009 are also given in the paper.

[Epidemic process of rubella during mass vaccination of children].

AIM: To reveal features of rubella epidemic process during start of mass immunization and to determine rubella virus genotypes circulating in Saint-Petersburg. MATERIALS AND METHODS: Official data on rubella morbidity during 1995-2007 and number of vaccinated against rubella children and adults were used in this study. During 2006-2008 males aged 17-20 years with rubella diagnosis were eligible for laboratory test on rubella. Nasopharyngeal swabs and blood specimenswere tested by PCR and virus isolation on cell culture (PK13). Genotyping of isolates was performed on the basis of 600 nucleotide sequence of E1 gene from 8731 to 9653 n.p. RESULTS: It was shown that mass vaccination of children and young women against rubella during 4 years resulted in 3-fold drop of rubella incidence inwhole population, which diminishes the probability of infection in pregnant women and born of children with congenital rubella syndrome. In age structure of rubella morbidity the proportion of children aged 3-6 and 7-14 years decreased by 1.5-fold. Epidemic process loss the features of autoregulating system (periodicity and seasonal incidence peaks). Results of genotyping showed that isolates belonged to genotype 1E. High degree of homology (97.7-99.6%) to isolates from Barnaul and Belorussia was demonstrated. CONCLUSION: Issues on isolates' origin and success of measures on elimination of endemic rubella could be resolved by further studies on isolation and genotyping of rubella virus strains in Saint-Petersburg and North-East region of Russian Federation in the whole.

Synthesis and biological activity of water-soluble polymer complexes of arbidol.

We have synthesized water-soluble complexes between the antiviral drug arbidol and polymer compounds with molecular masses of 19-31 kDa representing copolymers of acrylamide (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AAMPS). The complexes are less toxic than arbidol and retain the high level of antiviral activity of this drug. The content of arbidol in the obtained complexes is within 26.4-32.1 mass%. The antiviral activity of the synthesized polymeric complexes against all studied viruses, including human epidemic influenza virus A (H3N2), bird highly pathogenic influenza virus A (H5N1), herpes type 1 virus (HSV-1), and adenovirus type III (AV-III) is comparable to the antiviral effect of nonmodified arbidol. The in vitro toxicity of the obtained complexes is about one order of magnitude lower than that of nonmodified arbidol; the pharmacological index, four times that of the initial low-molecular-weight drug. The synthesized water-soluble polymer complexes of arbidol can be useful in pharmacology since they can serve as the basis for new effective and safe parent antiviral substances and related formulations.

[Antiviral action of some antioxidants/antihypoxants and their combinations with remantadine against human influenza A(H3N2) virus studied in in vitro models].

The possible antiviral activity of preparations with antioxidant and/or antihypoxant properties was studied on two in vitro models of influenza infection: (i) in cultures of chorio-allantoic membranes of chicken embryos and (ii) in MDCK cells. Preparations under study were hypoxene, reduced glutathione, dihydroquercetin, trolox, coenzyme Q10, and the enzymatic preparation of superoxide-dismutase (recsod). Preparations possessing combined antioxidant/antihypoxic and detoxicating properties (reduced glutathione and hypoxene) produced a significant antiviral effect and enhanced the antiviral effect of rimantadine. The antiviral effect of these preparations was manifested by a decrease in the production of viral particles and, to a more pronounced degree, by the inhibition of cytopathogenic action of virus on cultured cells, which was revealed in the tests for the activity of respiratory enzymes. In contrast to the compounds containing thio or sulfo groups, the antioxidants of "direct action" (free radical scavengers) - coenzyme Q 10, trolox, quercetin and the enzymatic preparation recsod did not show any pronounced protective effect and in some cases even enhanced the production of viral particles and decreased the antiviral action of rimantadine.

Etiology of influenza viruses isolated in Russia from 1998 up to present time.

Influenza epidemic events in Russia from 1998 up to 2005 were associated with the circulation of influenza A (H3N2), A (H1N1) and B viruses. The antigenic analysis revealed that the evolution of A (H3N2) viruses proceeded as following: A/Sydney/05/97-->A/Panama/2007/99-->A/Fujian/411/02-->A/Wellington/01/04; A (H1N1) viruses: A/Bayern/07/95-->A/Bejing/262/95-->A/New Caledonia/20/99; B viruses evolved as two distinct lineages: Victoria- and Yamagata-like viruses. Our results have shown that the evolution in Russia coincided the World trends.

[Development and application of immunoenzyme test-system for the diagnosis of acute cytomegalovirus infection]. / Razrabotka i primenenie immunofermentnoi test-sistemy dlia diagnostiki ostroi tsitomegalovirusnoi infektsii.

Enzyme immunoassay for the detection of IgM antibodies to human cytomegalovirus (CMV) has been developed. Use of horseradish peroxidase conjugated monoclonal antibodies to human IgM helped create a highly specific test system. The rheumatoid factor was removed from the serum by staphylococcal reagent containing protein A. The results of the newly developed assay are in good correlation with the clinical course of the disease and data of polymerase chain reaction and the test making use of the Labsystem. Cytomegalovirus IgM EIA Kit.

[The genomic variability of adenovirus serotype 7]. / Genomnaia izmenchivost' adenovirusov serotipa 7.

Genetic heterogeneity and evolutionary relationships among selected strains of adenovirus type 7 (Ad7) isolated in the former USSR were examined using the restriction endonuclease Cfr131 with a 4-base recognition cleavage site. The population of adenovirus type 7 showed less expressed genome polymorphism and significant structural distinctions as compared with that of adenovirus type 3. The Ad7 evolution in the USSR (1976-1988) independent on that demonstrated in other countries is discussed.

[Changes in central hemodynamics in persons with borderline arterial hypertension during work-related activities]. / Izmenenie tsentral'noi gemodinamiki u lits s pogranichnoi arterial'noi gipertoniei v usloviiakh trudovoi deiatel'nosti.

Changes in the function of the cardiovascular system were studied in 30-39- and 40-49-year-old healthy subjects and patients with borderline arterial hypertension (BAH) who worked 8 or 12 hours every day. During an 8-hour working day, altered central hemodynamics was shown to be detected both in healthy subjects and BAH patients only at the age of 30-39 years and reflected by higher stroke volume (SV), higher cardiac output (CO) and lower total peripheral resistance (TPR) in healthy subjects and diminished heart rate (HR), CO in BAH patients. With this, the distribution of hemocirculatory patterns remained the same as it had been before work. After 12-hour work, the central hemodynamic changes were unindirectional in all the groups in question: decreased HR, SV, CO, cardiac index and increased TPR. There was a decrease in hyperkinetic hemodynamic incidence and an increase in eu- and hypokinetic hemodynamic one.