Homogeneity of the structural glycoprotein from European isolates of tick-borne encephalitis virus: comparison with other flaviviruses.

Isolates of tick-borne encephalitis (TBE) virus from Finland, Germany, Czechoslovakia, Switzerland and Austria were compared with strains of the Far Eastern subtype isolated in Russia as well as Louping ill virus and other flaviviruses belonging to a different serocomplex: West Nile, Murray Valley encephalitis and Rocio viruses. Analysis of the structural polypeptides by SDS--polyacrylamide gel electrophoresis (SDS--PAGE) revealed identical mol. wt.

[Epidemiology of tick-borne encephalitis in Southern Germany (author's transl)].

A recently developed sensitive enzyme immunoassay for the detection of IgM antibodies to tick-borne encephalitis (TBE) virus was used to reinvestigate sera of patients with the clinical diagnosis of meningitis or encephalitis but without conclusive results in the complement fixation assay for TBE virus. 62 cases with sera positive for IgM antibodies to TBE virus collected from 1976 to 1980 were evaluated with regard to clinical and epidemiological aspects of the disease. Of the 62 cases, 37 had apparently been bitten by ticks.

A new enzymatic method for the determination of glucose.

A method for the determination of glucose is described. H2O2, produced by the action of glucose oxidase, is measured from the change in absorbance due to oxidation of NAD(P)H in the presence of catalase, aldehyde dehydrogenase and a high concentration of ethanol. The quality data of the method are equivalent to those of the hexokinase-glucose-6-phosphate dehydrogenase method used as reference.

Purification and characterisation of the cyclic AMP-dependent protein kinase, the C- and the R-protein from bovine liver.

A cyclic AMP-dependent protein kinase, its regulatory (R) and catalytic (C) protein were isolated from bovine liver, The cyclic AMP-dependent protein kinase showed two protein bands on SDS-polyacrylamide gel electrophoresis with molecular weights of 54 000 and 40 000. They correspond to the data for the separately isolated R-and C-protein. The molecular weight of the holoenzyme ranged from 172 000-179 000, depending on the estimation method.

Comparison of two different enzyme immunoassays for detection of immunoglobulin M antibodies against tick-borne encephalitis virus in serum and cerebrospinal fluid.

Two enzyme immunoassays for the detection in immunoglobulin M (IgM) antibodies against tick-borne encephalitis virus were compared, employing a solid phase coated either with antigen or with mu-chain-specific antiserum to human IgM. The latter IgM-capturing assay system proved to be more sensitive, and its superiority was especially prominent when high titers of tick-borne encephalitis virus-specific IgG antibodies in addition to specific IgM antibodies were present in the sample. The application of this test is a valuable extension of the diagnostic tools for the rapid diagnosis of tick-borne encephalitis by IgM detection.

Antigenic and immunogenic properties of defined physical forms of tick-borne encephalitis virus structural proteins.

Polymeric, delipidated glycoprotein complexes of defined size and composition were prepared from tick-borne encephalitis virus by solubilization with Triton X-100 or cetyltrimethylammonium bromide, followed by centrifugation into detergent-free sucrose density gradients. The antigenic reactivities and immunogenicities of these complexes were compared with those of complete inactivated virus. These glycoprotein preparations induced hemagglutination-inhibiting and neutralizing antibodies which proved to be protective in passive mouse protection tests and monospecifically reacted only with the viral envelope and not with the internal core.

Autoimmune rat T lymphocytes monospecific for acetylcholine receptors: purification and fine specificity.

We prepared highly purified acetylcholine receptor (AChR)-specific T lymphocytes from rats with experimental autoimmune myasthenia gravis (EAMG). Inbred rats were primed with AChR frm 3 different sources: from the electric organs of Electrophorus electricus and Torpedo californica and from denervated rat muscle. After 20 to 30 days, lymphocytes from regional lymph nodes (primary cells) were challenged with soluble AChR in vitro.

Serological diagnosis of acute tick-borne encephalitis by demonstration of antibodies of the IgM class.

A sensitive enzyme immunoassay is described for demonstrating specific antibodies of the IgM class to tick-borne encephalitis virus (anti-TBEV IgM). Anti-mu-coated, flat-bottomed microtiter plates are incubated with diluted patients' serum (2 hr at 37 degrees C), then with purified TBEV, and later with peroxidase-coupled anti-TBEV immunoglobulin for a further 2 hr. After washing the plates, orthophenylenediamine is added and the optical density is measured at 510 nm.

[Efficacy of Vaccination Against Tick-Borne Encephalitis].

Since 1973 blood samples have been investigated at random for the presence of antibodies to tick-borne encephalitis (TBE) virus in persons vaccinated with the Austrian TBE vaccine. The immunization schedule was to doses given 1 to 3 months apart and a third dose injected 9 to 12 months later. This resulted in a seroconversion rate of 96% (n=444) in the haemagglutination-inhibition (HI) test and of 99% in the ELISA.

A new spectrophotometric method for the determination of 5'-nucleotidase.

A spectrophotometric method is described for the determination of 5'-nucleotidase. In combination with the enzymes nucleoside phosphorylase and xanthine oxidase, inosine, formed by hydrolysis of 5'-IMP by 5'-nucleotidase, is cleaved phosphorolytically to hypoxanthine, which is oxidized to uric acid. In the presence of ethanol, the hydrogen peroxide formed is reduced by catalase and equivalent amounts of acetaldehyde are produced.

Formation of polymeric glycoprotein complexes from a flavivirus: tick-borne encephalitis virus.

Treatment of tick-borne encephalitis (TBE) virus with Triton X-100 (TX-100), octylglucoside (OG) or cetyltrimethylammonium bromide (CTAB) caused dissociation of the virus envelope into dimers or monomers of the glycoprotein V3. By centrifugation into detergent-free sucrose density gradients, these subunits were found to reassociate and to form haemagglutinating homogeneous glycoprotein complexes sedimenting at 15 to 16, 16 to 18 and 11 to 23S after TX-100, OG and CTAB treatment, respectively. Glycoprotein complexes obtained after TX-100 solubilization contained less than 1% lipid and detergent by weight.

Chemical crosslinking of tick-borne encephalitis virus and its subunits.

Tick-borne encephalitis (TBE) virus was crosslinked by dimethylsuberimidate (DMS) and the cleavable dimetyl 3,3'-dithiobispropionimidate (DTBP). Analysis by SDS-PAGE revealed polymers of the virus core protein V2 and the glyco protein V3 in continuously decreasing amounts. The formation of higher order complexes was not favoured over the formation of lower order complexes.

Isolation of dimeric glycoprotein subunits from tick-borne encephalitis virus.

Crosslinking of tick-borne encephalitis virus with dimethylsuberimidate followed by SDS-PAGE analysis yielded polymers of the core protein V2 and the viral glycoprotein V3, both in continuously decreasing amounts. As the two structural entities of flaviviruses - cores and viral envelope - are apparently crosslinked independently from one another, we employed this property to study the action of different detergents at various concentrations on either the viral envelope or core. Triton X-100 and octylglucoside had no influence on the core but did dissociate the envelope into a V3-dimer.

A new spectrophotometric assay for enzymes of purine metabolism. IV. Determination of adenosine deaminase.

A new spectrophotometric method for the determination of adenosine deaminase is described. Adenosine is deaminated to inosine, the latter is cleaved by an inosine-guanosine specific nucleoside phosphorylase to hypoxanthine and ribose-1-phosphate. Hypoxanthine can be oxidized further to uric acid by xanthine oxidase or to allantoin by xanthine oxidase and uricase.

Immunogenicity and reactogenicity of a highly purified vaccine against tick-borne encephalitis.

Immunogenicity and reactogenicity of a vaccine containing inactivated tick-borne encephalitis virus prepared by continuous flow zonal ultracentrifugation were compared with those of a previously used, less purified vaccine. Antibody response as measured by hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) was 93% after two vaccinations and 100% after a third dose. The zonally purified vaccine impressively reduced the incidence of side reactions.

[Preliminary results of a pilot study on the influence of pemoline on cerebral concentrations of lactate, pyruvate, creatine, creatinephosphate, ATP, AMP, and ADP (author's transl)].

Cerebral lactate, pyruvate, ATP, ADP, creatine and phosphocreatine concentrations were determined in old, 600 g, rats during daily application of 20 mg pemoline (Tradon) (n = 11) and placebo (n = 10). After application for 21 days there were observed no significant differences in ATP, ADP, AMP, creatine and phosphocreatine concentrations between pemoline and placebo treated rats. On the other hand, in pemoline-rats, there was a significant decrease in pyruvate, lactate concentrations and in lactate/pyruvate ratio.