Paavo Väänänen

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An application of the haemolysis-in-gel (HIG) technique was developed to quantitate antibodies against the human coronavirus OC43. Preinfection and convalescent sera from two patients with verified OC43 infection showed a significant increase in antibody titres measured by HIG as well as by haemagglutination-inhibition (HI). 241 of the other 306 sera tested(More)
A voltage-controlled oscillator (VCO) based on double cross-coupled multivibrator structure with a center frequency of 4.3 GHz and a tuning range of 2 GHz has been designed and implemented in standard 0.35m BiCMOS technology. The measured phase noise is 113 dBc/Hz at 600-kHz offset frequency from the carrier. The VCO draws 14.6 mA from the 2.5-V supply.
Semliki Forest, Sindbis and rubella viruses can fuse erythrocytes from several different species. Large fusion vesicles consisting of tens to hundreds of red blood cells were seen under optical conditions. For the haemagglutination and cell fusion to occur the adsorption of virus and further incubation had to be carried out at pH 5.8. Haemagglutination took(More)
Purified preparations of Semliki Forest (SFV) and Sindbis virus haemolyse red blood cells from several species of animals and birds. The optimal haemolysis by SFV was obtained at pH 5.8 with 1-day-old chick erythrocytes incubated at room temperature. Considerable variation in haemolytic activity was observed between different virus preparations purified by(More)
Large-scale purification of rubella virus from tissue culture fluid and preparation of an experimental rubella subunit vaccine are described. The virus, purified isopycnically in sucrose gradients, was Tween 80-ether treated, and the product was filtered sterile. The vaccines were of two types, formalinized and nonformalinized. They were not infectious, had(More)
A stabilized modification of the single radial haemolysis-in-gel (HIG) technique was developed. Crude mumps or influenza virus preparations were coupled to erythrocytes with CrCl3 and mounted in agarose gel containing diluted guinea pig serum. Serial serum samples taken from 204 conscripts before and after vaccination with a killed mumps vaccine were(More)
The proportions of six immunoglobulin isotypes (IgA, IgM, IgG1, IgG2, IgG3, and IgG4) in rubella antibody responses were quantified in 40 serum samples (20 patients). The first sample from each patient was taken during the first days of the illness, and the second sample 10 +/- 1 days later. A tenfold average increase in antibody concentration was observed(More)
The hemolysis-in-gel (HIG) technique was adapted for rubella antibody determinations. Use of sucrose gradient purified virus and its coupling with CrCl3 to chicken erythrocytes resulted in gel plates that could be stored for several weeks and were suitable for reproducible antibody determinations. In a serological survey of young healthy adults the HIG(More)
Two tests were introduced recently for assessment of the avidity of rubella immunoglobulin antibodies. In the quantitative test--avidity-enzyme linked immunosorbent assay (ELISA)--IgG antibodies obtained from individuals shortly after primary infection with rubella virus are distinguished from those with past immunity by their antigen-elution(More)