[Polytypic strains in the genofund of tick-borne encephalitis virus].

Eighteen polytypic tick-borne encephalitis virus (TBEV) strains containing the fragments of E and NS1 protein genes of Siberian and Far Eastern, occasionally Siberian and European subtypes were isolated in the European and Asian parts of the tick-borne encephalitis (TBE) area. They were identified using real-time polymerase chain reaction, hybridization-fluorescence detection with genotype-specific probes, restriction fragment length polymorphism analysis, and E protein sequencing. The polytypic strains were isolated from individual Ixodes persulcatus ticks, their pools, from the blood of patients and the brain of dead patients.

Non-hemagglutinating flaviviruses: molecular mechanisms for the emergence of new strains via adaptation to European ticks.

Tick-borne encephalitis virus (TBEV) causes human epidemics across Eurasia. Clinical manifestations range from inapparent infections and fevers to fatal encephalitis but the factors that determine disease severity are currently undefined. TBEV is characteristically a hemagglutinating (HA) virus; the ability to agglutinate erythrocytes tentatively reflects virion receptor/fusion activity.

[Evolution of tick-borne encephalitis and a problem of evolution of its causative agent].

The evolution of tick-borne encephalitis (TBE) is marked by the expanded nosological area, the transformation of landscapes, the formation of anthropurgic foci, the change of environmental systems, the increase of mortality rate mainly among urban dwellers, as well as pathomorphism. The evolution of natural TBE virus (TBEV) populations was studied in Eastern and Western Siberia, Middle Urals, and the European part of the nosological area. The paper first describes the types of evolutionary transformations of viral populations under the conditions of a varying environmental and epidemiological situation.

[Comparative analysis of virulence of the Siberian and Far-East subtypes of the tick-born encephalitis virus].

The Siberian subtype of the tick-borne encephalitis virus (TEV) is different from the Far-East subtype by a moderate virulence observed in Siberian hamsters and by a low infection development rate (100 strains were compared). No differences were found in neuro-invasiveness. Clinical findings and experiments with monkeys denote the ability of the Siberian subtype to provoke severe forms of tick-borne encephalitis (TBE).

[The Siberian and Far-Eastern subtypes of tick-borne encephalitis virus registered in Russia's Asian regions: genetic and antigen characteristics of the strains].

Agar gel precipitation test with cross-adsorbed immune sera was used for the antigenic differentiation of strains of tick-borne encephalitis virus (TBEV). Fifty strains of the Far East TBEV serotype and 46 strains of the Siberian (Aina) TBEV serotype were isolated from Ixodes persulcatus, which is the main vector of the above TBEV subtypes in the Asian and European parts of Russia. The fragment of the envelope protein gene was sequenced for TBEV strains.

[Specific determination of flaviviruses by molecular hybridization with synthetic deoxyoligonucleotide probes].

Molecular probes were designed for the purpose of specific determination of flavioviruses transmitted by the ticks of tick-borne encephalitis (TBE) and Omsk hemorrhagic fever (OHV) as well as by mosquitoes of Japanese encephalitis (JE), North Nile (NN), Murrey Valley encephalitis (MVE), Saint-Lois encephalitis (SLE), dengue 1-4 and of yellow fever (YF). The probes are synthetic deoxyoligonucleotides with the 18-20 long basis and complementary for the RNA fragments defined by computer analysis. The thus obtained probes, which specifically hybridize themselves with the sets of the TBE virus or of the OHV virus and do not hybridize themselves with other TBE viruses' sets.

[A comparative analysis of proteins from persistent and antigen-defective strains of tick-borne encephalitis virus].

Structural (E) and three nonstructural (NS1, NS3, and NS5) proteins of persistent and antigen-defective strains of tick-borne encephalitis virus are compared by immunoblotting with monoclonal antibodies to the corresponding proteins of strain Sofyin. Appreciable phenotypical differences were revealed between antigen-defective strains, but no immunological modifications as concerns the studied antigenic structures. The size of the reference NS3 protein differed from that of the persistent virus strains.

[Japanese encephalitis in citizens of Russia who travel abroad].

Typical and atypical forms of Japanese encephalitis (JE) in the Russians visiting Asian countries endemic for JE are described. A patient who contracted the disease in China developed 5 months after returning to Russia acute meningoencephalitis with mental disorders and a lethal outcome on day 5 with bulbar symptoms. JE virus (strain SP-69) was isolated from his brain.

[Vergina-like strains of tick-borne encephalitis in Russia].

The Greek strain Vergina representing an individual third serotype of tick-borne encephalitis (TBE) virus has been compared with 13 TBE strains isolated on the territory of Russia and Central Asia (in Kirghizia). A kit of deoxyoligonucleotide probes complementary to genome sites of Neudorfle strain of the TBE Central European subtype (protein C and prM genes) and of strain Sofyin of the Eastern subtype (protein E, C, M, prM, ns 1, ns 2b, ns 4b genes) was used in molecular hybridization of nucleic acids. Vergina strain was referred to the genetic variant VI prevalent in the western part of the East European plain, in Udmurtia, in the Altai mountains, and in West Siberia.

[The genetic characteristics of the Vergina serotype of the tick-borne encephalitis virus and its pathogenetic traits].

The Greek Vergina strain of tick-borne encephalitis (TBE) virus was studied in comparison with 7 other strains by molecular hybridization of nucleic acids and by clinicomorphological markers of pathogenicity for monkeys and Syrian hamsters. By the genetical features the Vergina strain differed from the eastern and western TBE subtypes but was found to be similar to the strains of other subtypes of the Urals-Siberian, east-Siberian (Aina-1448) and Central Asian antigenic variant. This group of strains hybridized with cDNA at 65 degrees C only in the absence of 50% formamide, reacted with probe 1115 complementary to protein E gene, with 1-3 probes complementary to the conservative region of the genome but did not react with the probes corresponding to the variable regions of the genome.

[The phenomenon of antigenic defectiveness in naturally circulating strains of the tick-borne encephalitis virus and its possible connection to seronegative forms of the disease].

Ten strains of tick-borne encephalitis (TBE) virus isolated from single specimens of I. persulcatus ticks were studied. The strains were divided into antigenically complete (AC) and antigenically defective (AD), depending on the presence or absence of some virus antigens in concentrated virus preparations, characteristics in rocket immune electrophoresis (RIEP), rate and intensity of humoral immune response in monkeys and rabbits, and plaque size in SPEV cell culture.

[Deoxyoligonucleotide probes that differentiate antigenic and pathogenetic variants of the tick-borne encephalitis virus].

Experiments on molecular hybridization were carried out using a panel of 11 deoxyoligonucleotide probes complementary to different parts of tick-borne encephalitis (TBE) virus, strain Sophyin, genome. Under study were the TBE virus strains differing by 3 criteria: (1) source of isolation (patients with acute and chronic TBE, Ixodes persulcatus and D. nuttalli ticks, small mammals); (2) serotype (eastern and Siberian Aina/1448), (3) virulence for Syrian hamsters.

Bioartificial liver using hepatocytes on biosilon microcarriers: treatment of chemically induced acute hepatic failure in rats.

An artificial liver support procedure based on hemoperfusion via hepatocytes cultured on microcarriers is described. The efficiency of the system was assessed by the survival rate of rats treated with either lethal dosage of 7% CCl4 [30 ml/kg body weight (b.w.

LDL- and agonist-induced Ca(2+)-mobilization in platelets of healthy subjects and in patients with familial hyperlipoproteinemia type II.

LDL induced a reversible increase in [Ca2+]i in platelets of healthy subjects and FH-patients. In both groups the effects of LDL were potentiated 2.3-fold by epinephrine.

Large-scale production and cultivation of hepatocytes on Biosilon microcarriers.

A method for large-scale production of hepatocytes on microcarriers have been developed for the purpose of bioartificial liver support system. Hepatocytes obtained by collagenase treatment of rat liver were efficiently attached and spread on a microcarrier surface in the presence of O2-saturated perfluorodecalin. In order to compare the metabolic activities of hepatocytes under long-term cultivation on microcarriers with those of cells under conventional monolayer culture, some liver-specific functions were investigated.

[Immunogenicity and stability of a Soviet inactivated cultured vaccine against Japanese encephalitis].

Six immunologically active vaccine batches inducing a specific antibody to Japanese encephalitis (JE) virus were obtained in serial manufacture of the preparation. In HI tests, the minimal antibody titre was 1:80, the maximal 1:320, neutralization index 1g was 3.7 to 5.

[Use of hepatocytes cultured in microcarriers for correction of acute hepatic insufficiency].

The ability of hepatocytes cultured on Biosilon microcarriers to secrete albumin and to conjugate bilirubin were examined for the purpose of developing an artificial liver support system. Cultured hepatocytes were able to synthesize 100-120 micrograms albumin per 10(5) cells in 24 hours and to conjugate about 20 micrograms/hr of bilirubin for at least 5 days. Rats with liver failure caused by i.

[Simultaneous separation of creatine kinase and lactate dehydrogenase isoenzymes using an electrophoresis method].

A specific and sensitive rapid method for simultaneous electrophoretic separation of the blood serum creatine kinase (CK) and lactate dehydrogenase (LDH) isoenzymes is described, fit for rapid diagnosis. A common electrophoresis scheme was used for the separation of both enzymes on the same cellulose acetate plate. Then the isoenzymes were separately detected by their enzymic activities.

[The Aĭna/1448 serotype of the tick-borne encephalitis virus].

The antigenic structure of 48 tick-borne encephalitis virus (TBE) strains isolated in the Irkutsk region and the Buryat ASSR in 1960-1981 was studied. Antigenic analysis was performed by the agar gel diffusion-precipitation test using adsorption of the immune sera. A new group of 31 TBE virus strains was found to belong to the Aina/1448 antigenic type.

[Characteristics of tick-borne encephalitis virus strains isolated from patients with chronic diseases of the central nervous system].

Two groups of tick-borne encephalitis (TBE) virus strains were studied: Group 1, 5 strains isolated from patients with chronic TBE with progressive course, Group 2, 13 strains isolated from residents of an endemic locality, with chronic diseases of the CNS (amiotrophic lateral sclerosis, epidemic encephalitis, polyoencephalomyelitis, syringomyelia, etc.). Strains of both groups belong to two serotypes of TBE virus: mid-Siberian and Transbaikal (synonym Aina/1448) and eastern.