Effect of Changes in the Redox Status on Biofilm Formation in Escherichia coli.

Changes in the redox balance in the medium and in Escherichia coli cells significantly affect the ability of bacteria to form biofilms. An increase in the level of aeration in the culture of wild-type bacteria led to a 3-fold decrease in the mass of biofilms. Mutants lacking components of the glutathione and thioredoxin redox systems, as well as transporters involved in the transmembrane cycling of glutathione, demonstrated increased biofilm formation ability. The effect of exogenous glutathione on biofilm formation depended on the culturing conditions. The addition of 0.1-1 mM Trolox (a water-soluble analog of vitamin E) was accompanied by a 30-40% reduction in biofilm formation.

[Immunological safety and sensitizing effect of an MB-7-based vaccine against hepatitis A]. / Immunologicheskaia bezopasnost' i sensibiliziruiushchee deistvie vaktsiny protiv gepatita A na osnove shtamma MB-7.

The influence of a vaccine based on the MB-7 strain of hepatitis A virus (VP-MB-7) designed at the "Vector" Center of Virology and Biotechnology was studied. VP-MB-7 was found to provoke no allergic response and to have an activating effect on the specific and non-specific responses of cell and humoral immunity similar to those evoked by hepatitis A vaccine "Hep-A-in Vac".

[Safety research of a vaccine preparation in hepatitis A derived from the MB-7 rapidly growing strain]. / Izuchenie bezvrednosti vaktsinnogo preparata protiv gepatita A iz bystrorastushchego shtamma MB-7.

A study was undertaken to prove that a vaccine drug based on the fast-growing MB-7 (MB-7 VD) of hepatitis A virus (HAV) is safe. It was established that MB-7 VD, when once injected to white outbred mice and when 4 times injected to Hartley guineas pigs, did not cause any hematological and biochemical changes in the peripheral blood or in the condition of the central nervous system of experimental animals, which shows that MB-7 VD is free of any toxic properties.

[Detection of antibodies to HIV virus in saliva by express-tests in Uzbekistan]. / Opredelenie antitel k virusu immunodefitsita cheloveka v sliune s pomoshch'iu ékspress-testa v Uzbekistane.

Saliva tests, when used in screening for antibodies to HIV virus (anti-HIV), makes testing safer, easy-to-fulfill (even outside clinic) and acceptable for a majority of examinees. The main quality parameters of express-test for the detection of anti-HIV in saliva were evaluated for the purpose of using the related approach in the HIV epidemiological supervision. Saliva samples and sera of 81 HIV-infected patients and of 99 presumably non-infected persons were investigated by the "OraQuick" express-test. The data obtained were compared with the results of ELISA-based serum testing. The sensitivity of "OraQuick" made 95% and its specificity was 100%. The test is appropriate for epidemiological investigations and HIV epidemiological supervision but it cannot be recommended for the blood transfusion service.

[Subtypes of HBsAg of the hepatitis B virus in Western Siberia]. / Subtipy HBsAg virusa gepatita B v Zapadnoi Sibiri.

HBs antigens were subtyped in blood samples of intravenous drug-addicts (IDA) and of donors from as many as 10 cities of Western Siberia by using the immune-enzyme assay with 6 high-specific monoclonal antibodies. Two HBsAg subtypes were found, in a ratio of 3% ayw2: 97% ayw3 (varA and varB), in IDA blood samples from Novosobirsk. Three HBsAg subtypes were found, in a ratio of 57% ayw2: 42% ayw3 (varA and varB): 1% adw2, in the donors' blood samples. The obtained data are sufficient for developing the first national sera panel containing different HBsAg subtypes of hepatitis B virus typical of Russia.

[Characteristics of reactogenic and immunogenic properties of the children's variant of the domestic vaccine, "Gep-A-in-Vak", against hepatitis A]. / Kharakteristika reaktogennykh i immunogennykh svoistv detskogo varianta otechestvenoi vaktsiny protiv gepatita A "Gep-A-in-Vak".

Russian cultural concentrated inactivated vaccine protecting from hepatitis A--Hep-A-in-vac was used for immunization of children. The vaccine is slightly reactogenic and completely safe in children aged 3-17 years vaccinated twice in a dose of 0.25 ml. Double immunization of seronegative children with a 1-month interval led to conversion in 89.7% children. In 64.1% children titers of antibodies to hepatitis A virus reached 20 mIU/ml and higher, which indicates rather high antigenic activity of the vaccine.

[Evaluation of the effectiveness of substance for diagnosing rotaviral infection under field conditions]. / Otsenka éffektivnosti preparatov dlia diagnostiki rotavirusnoi infektsii v usloviiakh naturnykh ispytanii.

A universal mathematical approach (algorithm) to assessment of the efficacy of new preparations for the diagnosis of rotavirus infection, analysis and processing of the results involves assessment of the detection rate of infection, specificity of preparations, probability of positive and negative diagnoses, total index of coincidence of results of diagnosis with the reference method, and chi 2 and phi2 coefficients indicating the reliability of relation to the reference method and the strength of this relation. Diatest software is proposed for accelerating statistical processing of the results. Use of the algorithm and software permits assessing the efficacy of diagnostic agents for rotavirus and other infections.

[Hep-A-in-Vac, a Russian cultured concentrated inactivated vaccine against hepatitis A]. / Izuchenie otechestvennoi kul'tural'noi kontsentrirovannoi inaktivirovannoi vaktsiny protiv gepatita A "Gep-A-in-Vak".

The results of the study of the reactogenicity, safety and immunological activity of Russian cultural vaccine against hepatitis A are presented. The vaccine was found to have specific safety, moderate reactogenicity and pronounced immunological activity. In addition, the study of the prophylactic efficiency of the vaccine in the pre-epidemic period of the outbreak of hepatitis A morbidity in a group exceeding 14,000 adults was carried out. The study revealed high prophylactic efficiency of the vaccine (its efficiency rate was equal to 97.7%). On the basis of materials thus obtained vaccine "Hep-A-in-Vac" was recommended for use in medical practice for the prophylaxis of hepatitis A among adults.

[Comparative study of the immunogenicity of the inactivated hepatitis A vaccine Hep-A-in-vac from experimental and clinical data]. / Sravnitel'noe izuchenie immunogennosti inaktivirovannoi vaktsiny protiv gepatita A gep-A-in-vak po dannym éksperimental'nykh i klinicheskikh issledovanii.

Comparative analysis of the specific activities of various batches of Hep-A-in-Vac vaccine showed that the immunologic efficacy of the agent directly depended on the content of hepatitis A virus antigen in the vaccine dose. The results of studying the immunogenicity of the agent on volunteers are compatible with the results of experimental studies and indicate that the test of guinea pigs adequately assesses this characteristic. Assessment of the immunogenic properties of Hep-A-in-Vac prepared using improved technology indicates that Russian vaccine injected three times in a dose containing at least 40 U EIA ensures 87.5% seroconversion in adult seronegative volunteers with the mean geometrical titer of antibodies to hepatitis A virus equal to 683 mIU/ml.

[Optimization of preparation conditions of an inactivated hepatitis A vaccine and its characteristics]. / Optimizatsiia uslovii polucheniia inaktivirovannoi vaktsiny protiv gepatita A i ee kharakteristika.

Modernization of the protocol and optimization of the technology of preparation of inactivated hepatitis A vaccine helped prepare the experimental lots of inactivated vaccine meeting all the requirements to such preparations and the WHO recommendations.

[Evaluation of reactivity and immunogenicity of a cultured concentrated inactivated vaccine against hepatitis A "Hep-A-In-Vak"]. / Otsenka reaktogennosti i immunogennosti kul'tural'noi kontsentrirovannoi inaktivirovannoi vaktsiny protiv gepatita A "Gep-A-In-Vak".

Clinical trials of inactivated hepatitis A vaccine Hep-A-in-Vac demonstrated its specific safety and moderate reactogenicity, manifesting by short-term fibrillar twitching of musculus deltoideus at the site of injection. After a course of three immunizations 87.5% seronegative vaccines developed a high level of specific antibodies to hepatitis A virus with at least 100 reverse values of titers. In controls antibody titers remained seronegative in 90% cases. These data indicate evident immunologic activity of Hep-A-in-Vac vaccine.

[The isolation and study of the characteristics of a cytopathic strain of the hepatitis A virus]. / Vydelenie i izuchenie kharakteristik tsitopaticheskogo shtamma virusa gepatita A.

A fast-growing cytopathic isolate of human hepatitis A virus (strain MB-7) was derived from fecal samples of infected patients and adapted to growth in FRhK-4 cell culture. A positive serum standard against HAV and electron microscopy were used to demonstrate that MB-7 belonged to human hepatitis A virus. The strain MB-7 induced plaque formation in FRhK-4 under agar overlay after 10-12 days of incubation. The PCR products of gene VP1 were cloned in E. coli and its primary structure was determined. MB-7 was shown to have more homology with HAV strains isolated in the USA and China.

[The results of a controlled field trial of a dried erythrocytic immunoglobulin diagnostic agent for detecting the hepatitis A virus antigen]. / Rezul'taty polevogo kontroliruemogo ispytaniia diagnostikuma éritrotsitarnogo immunoglobulinovogo sukhogo dlia vyiavleniia antigena virusa gepatitia A.

The results of the controlled field trial of lyophilized erythrocytic immunoglobulin diagnosticum for the detection of hepatitis A virus antigen in the urine and feces of patients are presented. This diagnosticum was used for the study of urine and fecal samples from 225 patients (of these, 176 had hepatitis A) and 54 healthy persons in the passive hemagglutination (PHA) test. Their blood sera were studied in the PHA test (to detect HBsAg) and the radioimmunoassay (to detect anti-HAV IgM). The immunoglobulin diagnosticum under study was found to be nonspecific and faintly sensitive and, therefore, unsuitable for use in medical practice.

[A comparative study of the sensitivity and specific activity of an immunoenzyme test system for determining class-M antibodies to the hepatitis A virus]. / Sravnitel'noe izuchenie chuvstvitel'nosti i spetsificheskoi aktivnosti immunofermentnoi test-sistemy dlia opredeleniia antitel klassa M k virusu gepatita A.

The diagnostic value of the first experimental production batches of assay kit "DIAGN-A-HEP", produced at the Institute of Poliomyelitis and Viral Encephalitides (USSR Acad. Med. Sci.) and intended for the determination of IgM to hepatitis A virus (HAV) in the enzyme immunoassay (EIA), has been studied in comparison with that of the internationally known and widely approved commercial EIA system "HAVAB-MEIA" for the determination of antibodies to HAV (the product of Abbott, USA). The study has revealed that the EIA kit "DIAGN-A-HEP" is highly sensitive and specific, and the diagnostic value of this kit is not inferior to that of the commercial assay system "HAVAB-MEIA". On the basis of this study the use of the EIA kits "DIAGN-A-HEP" in medical practice has been allowed by the decree of the Ministry of Health of the USSR.

[Immune status of subjects inoculated with inactivated influenza vaccines]. / Izuchenie immunnogo statusa liudei, privitykh inaktivirovannymi grippoznymi vaktsinami.

Inactivated whole-virion and split-virion influenza vaccines adsorbed on aluminium hydroxide did not suppress the immune system of the vaccinees. Immunization with these vaccine preparations induced the formation of both cell-mediated and humoral immunity in over 60% of the vaccinees.