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1.
Appl Radiat Isot ; 205: 111171, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38181577

RESUMO

Absolute gamma-ray emission intensities for 36 characteristic gamma rays from the decay of 224Ra, 212Pb, and their progeny were determined by measuring sources calibrated for activity by means of primary methods based on well-defined high-purity germanium (HPGe) detectors at both NIST and NPL. Results from the two laboratories agree with recent data evaluations, except for gamma rays with low emission intensities. The decay schemes have been re-balanced based on the new results. In addition, the half-life for 212Pb was measured using several HPGe detectors, ionization chambers, and a well-type NaI(Tl) detector.

2.
Vopr Virusol ; 68(6): 526-535, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38156568

RESUMO

INTRODUCTION: Polymerase proteins PB1 and PB2 determine the cold-adapted phenotype of the influenza virus A/Krasnodar/101/35/59 (H2N2), as was shown earlier. OBJECTIVE: The development of the reporter construct to determine the activity of viral polymerase at 33 and 37 °C using the minigenome method. MATERIALS AND METHODS: Co-transfection of Cos-1 cells with pHW2000 plasmids expressing viral polymerase proteins PB1, PB2, PA, NP (minigenome) and reporter construct. RESULTS: Based on segment 8, two reporter constructs were created that contain a direct or inverted NS1-GFP-NS2 sequence for the expression of NS2 and NS1 proteins translationally fused with green fluorescent protein (GFP), which allowed the evaluation the transcriptional and/or replicative activity of viral polymerase. CONCLUSION: Polymerase of virus A/Krasnodar/101/35/59 (H2N2) has higher replicative and transcriptional activity at 33 °C than at 37 °C. Its transcriptional activity is more temperature-dependent than its replicative activity. The replicative and transcriptional activity of polymerase A/Puerto Rico/8/34 virus (H1N1, Mount Sinai variant) have no significant differences and do not depend on temperature.


Assuntos
Alphainfluenzavirus , Vírus da Influenza A Subtipo H1N1 , Orthomyxoviridae , Vírus da Influenza A Subtipo H1N1/genética , Orthomyxoviridae/genética , Orthomyxoviridae/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Temperatura , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo
3.
J Endocrinol Invest ; 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38010598

RESUMO

PURPOSE: Hashimoto's thyroiditis (HT) is an autoimmune thyroid disease characterized by T lymphocyte-mediated destruction of thyroid follicles. To study the pathogenesis of HT and the efficacy of new substances for its treatment, an easily obtained and adequate to the human disease experimental model is needed. The aim of our study was to find out whether it is possible to induce experimental autoimmune thyroiditis (EAT) similar to Hashimoto's thyroiditis by injecting with thyroglobulin (Tg) without using agents that enhance its thyroiditogenicity and without taking into account the genetic sensitivity of animals. METHODS: Wistar rats were immunized with freshly isolated rat Tg or porcine Tg. In 8 weeks, histological studies of the thyroid and parathyroid glands were performed. Thyroid function and total serum calcium level were also evaluated. RESULTS: Immunization with both rat and porcine freshly isolated Tg caused T lymphocytic infiltration of the thyroid gland, thyroid follicle atrophy and degradation in Wistar rats. EAT caused by porcine Tg was characterized by greater severity than EAT induced with rat Tg. In 55% of rats with porcine Tg-induced EAT, oxyphilic metaplasia was detected in the parathyroid glands. In addition, low total serum calcium was observed in these rats. CONCLUSION: Two rat models of autoimmune thyroiditis were obtained. EAT caused in Wistar rats by immunization with rat Tg is similar to Hashimoto's thyroiditis. EAT induced with porcine Tg was accompanied by oxyphil cell metaplasia in the parathyroids and hypocalcemia.

4.
Appl Radiat Isot ; 202: 111044, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37797447

RESUMO

Terbium-152 is one of four terbium radioisotopes that together form a potential theranostic toolbox for the personalised treatment of tumours. As 152 Tb decay by positron emission it can be utilised for diagnostics by positron emission tomography. For use in radiopharmaceuticals and for activity measurements by an activity calibrator a high radionuclide purity of the material and an accurate and precise knowledge of the half-life is required. Mass-separation and radiochemical purification provide a production route of high purity 152Tb. In the current work, two mass-separated samples from the CERN-ISOLDE facility have been assayed at the National Physical Laboratory to investigate the radionuclide purity. These samples have been used to perform four measurements of the half-life by three independent techniques: high-purity germanium gamma-ray spectrometry, ionisation chamber measurements and liquid scintillation counting. From the four measurement campaigns a half-life of 17.8784(95) h has been determined. The reported half-life shows a significant difference to the currently evaluated half-life (ζ-score = 3.77), with a relative difference of 2.2 % and an order of magnitude improvement in the precision. This work also shows that under controlled conditions the combination of mass-separation and radiochemical separation can provide high-purity 152Tb.

5.
Mol Biol (Mosk) ; 57(5): 898-906, 2023.
Artigo em Russo | MEDLINE | ID: mdl-37752655

RESUMO

As an alternative to the classical method of erythrocyte hemagglutination, a latex agglutination assay based on the interaction of influenza viruses with the sialoglycoprotein fetuin immobilized on the surface of polystyrene microspheres has been developed. Twelve influenza A virus strains of different subtypes and two influenza B viruses of different lines were tested. Simultaneous titration of viruses using the classical hemagglutination test and the proposed latex agglutination assay showed similar sensitivity and a high degree of correlation (R = 0.94). The obtained microspheres can be used for titration of viruses that recognize and bind sialylated glycans as receptors. In particular, latex aggregation was also induced by the Newcastle disease virus.


Assuntos
Vírus da Influenza A , Orthomyxoviridae , Animais , Hemaglutinação , Testes de Fixação do Látex , Testes de Hemaglutinação
6.
Mol Biol (Mosk) ; 57(4): 632-646, 2023.
Artigo em Russo | MEDLINE | ID: mdl-37528783

RESUMO

A panel of 106 insertion/deletion (InDel) polymorphisms and a method of their genotyping on biochips were proposed as a new approach to genetic personal identification. Short lengths and low mutation rates are basic properties of InDel markers, which thus have significant advantages over short tandem repeats (STRs) widely used in forensics. The allele frequency distributions of all known InDel polymorphisms were studied in the five largest world populations (European, East Asian, South Asian, African, and American). Markers were selected to meet the following criteria: the minor allele frequency (MAF) is higher than 0.30; the physical distance between markers is greater than 3 Mb; there are no polymorphisms, tandem repeats, and palindromes in the flanking sequences; the AT/GC ratio is close to 1. A panel of 106 polymorphisms was thus formed; the average MAF was estimated at 0.396 in the five populations. The method developed for panel genotyping included one-step multiplex PCR and subsequent hybridization on a biological microarray. The average amplicon length was 72 bp. A sample of 201 residents of Moscow and St. Petersburg was tested to determine the main characteristics of the panel: the random matching probability (MP) was 1.89x 10^(-43) and the combined probability of paternity exclusion (CPE) was 0.99999999063. The method provides an alternative to molecular genetic personal identification based on the STR length variations.


Assuntos
Genética Populacional , Mutação INDEL , Polimorfismo Genético , Humanos , Frequência do Gene , Repetições de Microssatélites
7.
Data Brief ; 48: 109158, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37095758

RESUMO

This data article is related to the previous research, which addressed the development of a COVID-19 recombinant vaccine candidate. Here, we present the additional data in support of the safety and protective efficacy evaluation of two COVID-19 vaccine candidates based on the coronaviruses' S protein fragments and a structurally modified plant virus - spherical particles. The effectiveness of the experimental vaccines was studied against the SARS-CoV-2 virus in an in vivo infection model in female Syrian hamsters. The body weight of vaccinated laboratory animals was monitored. The histological assessment data of the infected with the SARS-CoV-2 virus hamsters' lungs are provided.

8.
Appl Radiat Isot ; 190: 110480, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36209648

RESUMO

Terbium-155 has been identified for its potential for single-photon emission computed tomography (SPECT) in nuclear medicine. For activity measurements, an accurate and precise half-life of this radionuclide is required. However, the currently evaluated half-life of 5.32(6) d with a relative standard uncertainty of 1.1% determines the precision possible. Limited literature for the half-life measurements of this radionuclide is available and all reported investigations are prior to 1970. Further measurements are therefore needed to confirm the accuracy and improve the precision of the half-life for its use in the clinical setting. Two samples produced and mass separated at the CERN-MEDICIS facility have been measured at the National Physical Laboratory by two independent techniques: liquid scintillation counting and high-purity germanium gamma-ray spectrometry. A half-life of 5.2346(36) d has been determined from the weighted mean of the half-lives determined by the two techniques. The half-life reported in this work has shown a relative difference of 1.6% to the currently evaluated half-life and has vastly improved the precision.


Assuntos
Medicina Nuclear , Radioisótopos , Meia-Vida , Radioisótopos/análise , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Espectrometria gama
9.
Mol Biol (Mosk) ; 56(5): 860-880, 2022.
Artigo em Russo | MEDLINE | ID: mdl-36165022

RESUMO

This paper presents a method for genotyping a panel of 60 single nucleotide polymorphisms (SNPs) using single-stage PCR followed by hybridization on a hydrogel biochip. The pool of analyzed polymorphisms consists of 41 SNPs included in the HIrisPlex-S panel, 4 SNPs of the AB0 gene (261G>Del, 297A>G, 657C>T, 681G>A), markers of the AMELX and AMELY genes, and 14 SNP markers of the Y chromosome haplogroups: B (M60), C (M130), D (CTS3946), E (M5388), G (P257), H (M2920), I (U179), J (M304), L (M185), N (M231), O (M175), Q (M1105), R (P224) and T (M272). These genetic data allow one to predict the phenotype of the desired person according to the characteristics of eye, hair, skin color, AB0 blood group, sex, and genogeographic origin in the male line. The setting protocol is simplified as much as possible to facilitate the introduction of the method into practice. The distribution of allele frequencies of the studied polymorphisms, as well as AB0 blood groups among the Slavs (N = 482), originating mainly from central Russia, was established.


Assuntos
Sistema ABO de Grupos Sanguíneos , Cromossomos Humanos Y , Cor de Olho , Técnicas de Genotipagem , Cor de Cabelo , Análise de Sequência com Séries de Oligonucleotídeos , Pigmentação da Pele , Sistema ABO de Grupos Sanguíneos/genética , Cromossomos Humanos Y/genética , Cor de Olho/genética , Cor de Cabelo/genética , Haplótipos , Humanos , Hidrogéis , Masculino , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Polimorfismo de Nucleotídeo Único , Pigmentação da Pele/genética , População Branca/genética
10.
Sovrem Tekhnologii Med ; 12(3): 77-81, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34795983

RESUMO

The aim of the study was to assess the effectivity of PMGMU2018h scale for evaluation of the state severity degree of patients suffering from obstructive jaundice relative to other common assessment scales. MATERIALS AND METHODS: Thirty physical parameters have been studied and compared according to different assessment scales in each of 258 patients with obstructive jaundice treated in three medical settings. RESULTS: The main drawback of the examined scales is the necessity to use the parameters for calculations not included in the medical and economic standards of the Russian Federation. This feature makes these scales unsuitable for making decisions on the tactics of managing a concrete patient in the hospitals of the Russian Federation. The scale developed by us for the assessment of the state severity of patients suffering from obstructive jaundice is completely devoid of subjectivism, does not depend on a surgeon's qualifications, and possesses high specificity to the given disease.


Assuntos
Icterícia Obstrutiva , APACHE , Humanos , Unidades de Terapia Intensiva , Icterícia Obstrutiva/diagnóstico , Federação Russa
11.
Biochem Mosc Suppl B Biomed Chem ; 15(2): 147-152, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34007413

RESUMO

The review considers complex, controversial, and individual effects of heparin and its derivatives on the bone and circulatory systems in dependence of the dose, the state of the cells and tissues of the recipient. General data on the anticoagulant activity of heparin and its derivatives are presented; special attention is paid to the effect of heparin on mesenchymal cells and tissues and its role in angiogenesis. We also discuss the ability of heparin to bind osteogenic and angiogenic biomolecules in the context of the development of systems for their delivery and sustained controlled release and propose a schematic representation of the positive and side effects of heparin as a delivery system for biomolecules in tissue engineering.

12.
Nature ; 590(7847): 566-570, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33627809

RESUMO

When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning1; this phenomenon has been a mystery in nuclear physics for over 40 years2,3. The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum4-12. Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors13,14, for the study of the structure of neutron-rich isotopes15,16, and for the synthesis and stability of super-heavy elements17,18.

13.
Sci Rep ; 11(1): 4, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420126

RESUMO

Bacteriophage communities associated with humans and vertebrate animals have been extensively studied, but the data on phages living in invertebrates remain scarce. In fact, they have never been reported for most animal phyla. Our ultrastructural study showed for the first time a variety of virus-like particles (VLPs) and supposed virus-related structures inside symbiotic bacteria in two marine species from the phylum Bryozoa, the cheilostomes Bugula neritina and Paralicornia sinuosa. We also documented the effect of VLPs on bacterial hosts: we explain different bacterial 'ultrastructural types' detected in bryozoan tissues as stages in the gradual destruction of prokaryotic cells caused by viral multiplication during the lytic cycle. We speculate that viruses destroying bacteria regulate symbiont numbers in the bryozoan hosts, a phenomenon known in some insects. We develop two hypotheses explaining exo- and endogenous circulation of the viruses during the life-cycle of B. neritina. Finally, we compare unusual 'sea-urchin'-like structures found in the collapsed bacteria in P. sinuosa with so-called metamorphosis associated contractile structures (MACs) formed in the cells of the marine bacterium Pseudoalteromonas luteoviolacea which are known to trigger larval metamorphosis in a polychaete worm.


Assuntos
Bacteriófagos/isolamento & purificação , Briozoários/microbiologia , Briozoários/virologia , Simbiose , Vírion/isolamento & purificação , Animais , Bacteriófagos/ultraestrutura , Briozoários/anatomia & histologia , Interações entre Hospedeiro e Microrganismos , Microbiota , Microscopia Eletrônica de Transmissão , Vírion/ultraestrutura
14.
Biomed Khim ; 66(6): 431-436, 2020 Nov.
Artigo em Russo | MEDLINE | ID: mdl-33372899

RESUMO

The review discusses the complex, ambiguous and individual effects of heparin and its derivatives on the bone and circulatory systems, in dependence of the dosage, the state of the cells and tissues of recipients. General data on the anticoagulant activity of heparin and its derivatives are presented; aspects of the effect of heparin on mesenchymal cells and tissues and its role in angiogenesis are considered in details. Particular attention is paid to the ability of heparin to bind osteogenic and angiogenic biomolecules: thus us especially important for the development of systems for their delivery and sustained controlled release. A schematic representation of the positive and side effects of heparin as a delivery system for biomolecules in tissue engineering is proposed.


Assuntos
Osteogênese , Bioengenharia , Heparina , Células-Tronco Mesenquimais , Engenharia Tecidual
15.
Mol Biol (Mosk) ; 54(6): 980-989, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33276361

RESUMO

The continued circulation of influenza A virus subtype H5 may cause the emergence of new potential pandemic virus variants, which can be transmitted from person to person. The occurrence of such variants is mainly related to mutations in hemagglutinin (HA). Previously we discovered mutations in H5N1 influenza virus hemagglutinin, which contributes to virus immune evasion. The purpose of this work was to study the role of these mutations in changing other, non-antigenic properties of the virus and the possibility of their maintenance in the viral population. Mutations were introduced into the HA gene of a recombinant H5N1 influenza A virus (VNH5N1-PR8/CDC-RG) using site-specific mutagenesis. The "variant" viruses were investigated and compared with respect to replication kinetics in chicken embryos, thermostability, reproductive activity at different temperatures (33, 37 and 40°C), and virulence for mice. Amino acid substitutions I155T, K156Q, K156E+V138A, N186K led to a decrease in thermal stability, replication activity of the mutant viruses in chicken embryos, and virulence for mice, although these effects differed between the variants. The K156Q and N186K mutations reduced viral reproduction at elevated temperature (40°C). The analysis of the frequency of these mutations in natural isolates of H5N1 influenza viruses indicated that the K156E/Q and N186K mutations have little chance to gain a foothold during evolution, in contrast to the I155T mutation, which is the most responsible for antigenic drift. The A138V and N186K mutations seem to be adaptive in mammalian viruses.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1 , Virulência/genética , Animais , Embrião de Galinha , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Virus da Influenza A Subtipo H5N1/fisiologia , Camundongos , Mutação , Infecções por Orthomyxoviridae/virologia , Replicação Viral
16.
Biochemistry (Mosc) ; 85(2): 224-233, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32093598

RESUMO

Recently we obtained complexes between genetically modified Tobacco Mosaic Virus (TMV) particles and proteins carrying conserved influenza antigen such as M2e epitope. Viral vector TMV-N-lys based on TMV-U1 genome was constructed by insertion of chemically active lysine into the exposed N-terminal part of the coat protein. Nicotiana benthamiana plants were agroinjected and TMV-N-lys virions were purified from non-inoculated leaves. Preparation was analyzed by SDS-PAGE/Coomassie staining; main protein with electrophoretic mobility of 21 kDa was detected. Electron microscopy confirmed the stability of modified particles. Chemical conjugation of TMV-N-lys virions and target influenza antigen M2e expressed in E. coli was performed using 5 mM 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and 1 mM N-hydroxysuccinimide. The efficiency of chemical conjugation was confirmed by Western blotting. For additional characterization we used conventional electron microscopy. The diameter of the complexes did not differ significantly from the initial TMV-N-lys virions, but complexes formed highly organized and extensive network with dense "grains" on the surface. Dynamic light scattering demonstrated that the single peaks, reflecting the complexes TMV-N-lys/DHFR-M2e were significantly shifted relative to the control TMV-N-lys virions. The indirect enzyme-linked immunosorbent assay with TMV- and DHFR-M2e-specific antibodies showed that the complexes retain stability during overnight adsorption. Thus, the results allow using these complexes for immunization of animals with the subsequent preparation of a candidate universal vaccine against the influenza virus.


Assuntos
Antígenos Virais/química , Vírus do Mosaico do Tabaco/química , Proteínas da Matriz Viral/química , Agrobacterium tumefaciens/citologia , Agrobacterium tumefaciens/virologia , Antígenos Virais/imunologia , Humanos , Influenza Humana/imunologia , Vírus do Mosaico do Tabaco/genética , Vírus do Mosaico do Tabaco/imunologia , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/imunologia
17.
G Chir ; 41(1): 66-72, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32038014

RESUMO

INTRODUCTION: The delayed diagnosis in emergency surgery can be associated with significant morbidity and mortality and often lead to litigations. The aim of the present work is to analyse the outcome in cases with non-trauma surgical emergencies wrongly admitted in non-surgical departments. METHODS: A retrospective trial in two independent University hospitals was conducted. The first group encompassed the patients worked-up in the Surgical unit of Emergency department (2014-2018). The second one included all cases visited Emergency department (2018). Only cases with acute abdomen and delayed diagnosis and operation were included. The analysis included the proportion of the delayed diagnosis, time between admission and operation, intraoperative diagnosis, complications and mortality rate. RESULTS: In the first group there were 30 194 visits in the surgical unit with 15 836 hospitalizations (52.4%). Twenty patients of the last (0.13%) were admitted in the Clinic of Infectious disease and subsequently operated. The mean delay between hospitalization and operation was 3 days (1-10). Seventeen patients (85%) were operated with mortality of 10%. In the second group, there were a total of 22 760 visits with 11 562 discharged cases. Of the last, 1.7% (n=192) were re-admitted in a surgical ward, 25 of which underwent urgent surgery (0.2%). CONCLUSIONS: The missed surgical cases represent only a small proportion of the patients in emergency department. The causes for wrong initial admissions in our series were misinterpretation of the symptoms, insufficient clinical examination and underuse of US and CT. The careful clinical assessment, point-of care US and CT may decrease the rate of the delayed diagnosis.


Assuntos
Abdome Agudo/diagnóstico , Abdome Agudo/cirurgia , Diagnóstico Tardio/estatística & dados numéricos , Serviço Hospitalar de Emergência/estatística & dados numéricos , Erros Médicos/estatística & dados numéricos , Admissão do Paciente/estatística & dados numéricos , Abdome Agudo/mortalidade , Emergências/epidemiologia , Hospitalização/estatística & dados numéricos , Humanos , Alta do Paciente/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos , Exame Físico , Estudos Retrospectivos , Avaliação de Sintomas , Tempo para o Tratamento/estatística & dados numéricos , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Ultrassonografia/estatística & dados numéricos
18.
Appl Radiat Isot ; 157: 109021, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31889679

RESUMO

High-energy tailing is an often-overlooked component in high-purity germanium gamma-ray spectrometry when performing the non-linear least squares fit of a full-energy peak. This component comes from the incomplete restoration of the baseline prior to the next pulse being processed and therefore is an issue of increased count rates. In the current work, the impact of this oversight is shown through the dynamics and decay characteristics of 224Ra and its radioactive decay progeny. Multiple measurements of two samples, separated from the decay progeny and at differing activities, have been made. The results of full-energy peak fitting of the convoluted 238.6 keV and 241.0 keV full-energy peaks with and without the high energy tailing component are presented. Trends in the observed activity that approximate the ingrowth of 212Pb have been observed where no high-energy tailing component is used, with maximum relative differences of 2% and 5% determined.

19.
Mol Biol ; 54(6): 861-869, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33424035

RESUMO

The continued circulation of influenza A virus subtype H5 may cause the emergence of new potential pandemic virus variants, which can be transmitted from person to person. The occurrence of such variants is mainly related to mutations in hemagglutinin (HA). Previously we discovered mutations in H5N1 influenza virus hemagglutinin, which contributes to virus immune evasion. The purpose of this work was to study the role of these mutations in changing other, non-antigenic properties of the virus and the possibility of their maintenance in the viral population. Mutations were introduced into the HA gene of a recombinant H5N1 influenza A virus (VNH5N1-PR8/CDC-RG) using site-specific mutagenesis. The "variant" viruses were investigated and compared with respect to replication kinetics in chicken embryos, thermostability, reproductive activity at different temperatures (33, 37 and 40°C), and virulence for mice. Amino acid substitutions I155T, K156Q, K156E+V138A, N186K led to a decrease in thermal stability, replication activity of the mutant viruses in chicken embryos, and virulence for mice, although these effects differed between the variants. The K156Q and N186K mutations reduced viral reproduction at elevated temperature (40°C). The analysis of the frequency of these mutations in natural isolates of H5N1 influenza viruses indicated that the K156E/Q and N186K mutations have little chance to gain a foothold during evolution, in contrast to the I155T mutation, which is the most responsible for antigenic drift. The A138V and N186K mutations seem to be adaptive in mammalian viruses.

20.
Appl Radiat Isot ; 154: 108863, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31513990

RESUMO

The nuclide 231Pa is a member of the 235U decay chain. It is a complex alpha emitter with 25 identified alpha emissions. Formerly published alpha-particle emission probabilities were derived from measurements taken with magnetic spectrometers. This work presents the first measurements made with semiconductor detectors. High-resolution alpha-particle spectrometry was carried out at CIEMAT and JRC using ion-implanted planar silicon detectors. Alpha-particle emission probabilities of 23 transitions were derived from deconvolutions of the spectra. For the major lines, uncertainties are lower than 1%, a significant improvement to existing data. The new data set will allow a more accurate evaluation of the decay scheme of 231Pa.

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