Heuristic statistical analysis of fluorescence fluctuation data with bright spikes: application to ligand binding to the human serotonin receptor expressed in Escherichia coli cells.

A statistical method for the analysis of fluorescence fluctuation amplitudes including bright spikes is presented. This situation arises e. g.

Reproductive failure in sows following experimental infection with a Belgian EMCV isolate.

In this study, a transplacental infection with fetal death was demonstrated following inoculation of pregnant sows with a Belgian encephalomyocarditis virus (EMCV) isolate. Eight multiparus sows were inoculated between 60 and 92 days of gestation with this EMCV-isolate to investigate its ability to cause reproductive failure in sows. Virus persistence and antibody titre in their offspring were also studied.

Simultaneous vaccination of piglets against foot-and-mouth disease and classical swine fever.

Six-week-old piglets, born of unvaccinated sows, were vaccinated against foot-and-mouth disease (FMD) with a trivalent, inactivated vaccine containing an adjuvant or vaccinated against classical swine fever (CSF) with a live attenuated vaccine or against both diseases simultaneously at two different sites. The antibody response to the FMD vaccine was not significantly influenced by the simultaneous vaccination against CSF. FMD vaccine administered simultaneously with the CSF vaccine produced a significantly higher antibody response to CSF than occurred with CSF vaccination only.

The serological response to foot-and-mouth disease vaccination is not affected by simultaneous infectious bovine rhinotracheitis/adenovirus/parainfluenza 3 vaccination.

Young calves were simultaneously vaccinated by subcutaneous route against foot-and-mouth disease (FMD) and against infectious bovine rhinotracheitis/adenovirus/parainfluenza-3 (IBR/Adeno/PI-3) by intranasal route. The serological response against the 3 FMD virus types of the FMD vaccine was clearly positive. There was no significant difference between results of simultaneous FMD and IBR/Adeno/PI-3 vaccination and FMD vaccination only.

Serological response to a booster foot-and-mouth disease vaccination with strains different from the primary vaccine.

Young calves were vaccinated with belgian foot-and-mouth disease (FMD) vaccine and revaccinated with either the same vaccine or with a foreign FMD vaccine. There was a significant serological response to the primary vaccine strains after the first vaccination which was greater following revaccination. At one and two months after revaccination there was no significant difference between the responses to revaccination with vaccine identical to the primary vaccine or with the foreign FMD vaccine.

Reduction of animal usage in the control of foot-and-mouth disease vaccines.

FMD vaccines were evaluated by comparing the results of a series of assays made on virus suspensions and on the final product, to mean values derived from a data base containing information on more than 300 accepted vaccine lots. The potency was estimated from the average percentage characterizing the vaccine, using the general mean in vivo protective dose, also provided by the data base. The correlation between the in vitro estimated potency and the in vivo tested potency as made routinely, was relatively low.

Use of short analytical ultracentrifugation runs for the isopycnic determination of foot-and-mouth disease virus concentration and density in autoformed caesium chloride gradients.

Short analytical ultracentrifugation runs of less than six hours with autoformed CsCl density gradients were used for routine FMDV density and concentration analysis. The values obtained after short runs were slightly higher for concentration and lower for density than after classical 22 h runs. These differences between the 6 and the 22 h values were related to virus strain and did not seem to result of the incomplete stabilisation of the CsCl gradient, but of the shorter virion/CsCl contact period.

[Evolution of anti-rota virus antibodies in the milk of cows treated in the last month of pregnancy either by adjuvated rotavirus vaccine or by the adjuvant fraction of the vaccine (author's transl)].

The authors describe the evolution of the secretion of anti-Rotavirus antibodies vaccine given three weeks before and repeated at the moment of parturition. Rota virus antibodies were detected at a high level during the three months test period with the Indirect Immunofluorescence Test, the seroneutralisation test and the immunofluorescence test. The four untreated animals excreted only rota-antibodies till day 6 .

Capacity of attenuated swine fever vaccines to prevent virus carriers in the vaccinated pigs, after contact with field virus.

Virus carriers have been detected in pigs vaccinated with attenuated Swine Fever vaccines after challenge with field virus. Virus carriers were found only if the vaccination was made with 20 PD50 or less. Clinical protection was obtained already with 8 PD50.

Routine titration of foot-and-mouth disease virus suspensions by analytical ultracentrifugation 2nd communication: sedimentation equilibrium method.

A routine method for the determination of the virus concentration in FMD virus cultures and vaccines was developed. This method was based on sedimentation equilibrium in the analytical ultraviolet scanning ultracentrifuge. The virus suspension was first clarified.

Immunogenic quality of foot-and-mouth disease virus.

Routine analysis of suspensions of foot-and-mouth disease virus and eluates of vaccine by the isopycnic method in analytical ultracentrifuge demonstrates the important heterogeneity of the viral population. This heterogeneity increases during inactivation of the virus by formol. In view of this dispersion of the physical characteristics of viral particles it may be asked (a) whether the immunogenic value is linked to the total quantity of particles which, we know, are very different from each other and of which we can determine only the partial or total parameters or (b) whether, on the contrary, the immunogenic value is linked to the activity of marginal particles, very small in number, and perhaps even quantitatively indistinguishable by the physical methods available.

Routine titration of foot and mouth disease virus suspensions by analytical ultracentrifugation. 1: Sedimentation method.

Infectivity and Complement Fixation (CF) tests are commonly used for the routine titration of Foot and Mouth Disease (FMD) virus suspensions. Only recently were techniques published for the routine determination of the virus concentration by the physical properties of the virions (Fayet et al., 1971; Barteling et al.

Studies about the adjuvant activity of saponin fractions in foot and mouth disease vaccine. III. Comparison of the irritant, adjuvant and hemolytic activities of six commercial saponins and their hemolytic fractions obtained by chromatography on sephadex G 100.

12 experimental vaccines were prepared to compare the irritant and adjuvant activity in cattle of 6 commercial saponin preparations and their hemolytic fractions. It is still not known if a single substance is responsible for the irritant, adjuvant and hemolytic activities of the saponin preparations. The quantities of saponin added were standardised on the base of a constant hemolytic activity rather than on a weight of powder per dose of vaccine base.