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L Bruckner

Publications and source records attributed to L Bruckner.

28 records · Page 2Linked to original sources

[The effectiveness of foot-and-mouth disease vaccines in Switzerland. I. Screening tests and herd immunity].

Protection of the Swiss national cattle herd against foot-and mouth disease is attempted by annual vaccination with inactivated trivalent (O, A, C) vaccines. With the serotype A5 as an example, this paper demonstrates the procedure of potency testing. Serological data obtained with two vaccines in primovaccinated feeder bulls showed that neutralizing antibodies developed within 7 to 14 days post vaccination. There was no statistically significant difference in the anti-serotype antibody titers induced by each of the vaccines; differences were seen between anti-O serotype and anti-A serotype antibody titers, regardless of which vaccine was used. Epidemiological analyses with about 3000 cattle demonstrated that single-vaccinated, and to a lesser degree twice-vaccinated, animals often had short lived immunity; that is, the antibody titers waned within a few months. In contrast, the majority of thrice and multiple vaccinated animals maintained relatively high antibody titers throughout the twelve month period of observation.

Animals↗

[The effectiveness of foot-and-mouth disease vaccines in Switzerland. II. Stability problems].

One of the vaccines that were used in 1988 to immunize the Swiss national cattle population against foot-and mouth disease (FMD) was apparently not stable. Data, provided by the manufacturer, indicated a high initial antigenic content for serotype O. Protection experiments at the end of the vaccination campaign, however, indicated a substantial loss of serotype O antigen in the vaccine. Serological data, obtained during the campaign indicated that only 12% of the primovaccinated animals and 63% of previously vaccinated animals received an amount of FMD viral antigen sufficient to induce protective immunity. The primovaccinated animals were revaccinated in fall 1988 with a new batch provided by the same manufacturer. The new vaccine induced high titers of neutralizing antibodies in primo- and an anamnestic response in revaccinated cattle.

Animals↗

[The control of infectious bovine rhinotracheitis (IBR) in Switzerland from 1978 to 1988].

The eradication of Infectious bovine rhinotracheitis/Infectious pustular vulvovaginitis (IBR/IPV) in Switzerland is reviewed. In 1978 IBR was reported in dairy cattle in the Eastern part of Switzerland. No preexisting eradication program was available at that time. In 1983, following a period of hesitation, the legal basis for the eradication of IBR was issued. This aim was achieved by: i) Controls and restrictions of the traffic of susceptible animals in order to prevent further transmission of IBR. ii) Slaughter of seropositive cattle, based on the assumption that animals with antibodies to BHV 1 were virus carriers and therefore an IBR-virus-reservoir. iii) The fact that besides the cattle population no BHV 1 reservoir existed in Switzerland. iv) Never licensing IBR-vaccines because they were not able to prevent the infection and the establishment of latency. The costs of the eradication program amounted to approx. SFr. 114,000,000. A total of 51,911 animals were slaughtered in order to eradicate IBR. An amount of SFr. 5,000,000 per annum is estimated to be necessary in order to maintain the favourable situation concerning IBR. In the future, the experience concerning IBR is applied for the prevention and control of other infectious diseases in the Swiss cattle population.

Animals↗

Reduction of the number of mice used for potency testing of human and animal rabies vaccines.

Eight different rabies vaccines were tested for their potency in the standard mouse potency test using 3-, 5- and 7-week-old mice. 5-week-old mice seem to be best suited for this purpose, variability from test to test could be reduced considerably. An ELISA was used in parallel for the evaluation of the rabies glycoprotein content of rabies vaccines. Results of the mouse potency test correlated well with those of the ELISA if highly purified human vaccines were tested. Unspecific reactions in the ELISA caused by adjuvanted veterinary vaccines could not be blocked. Further experiments will be needed in order to evaluate the potency of inactivated veterinary rabies vaccines by a in vitro test.

Aging↗

Upstream G gamma-globin and downstream beta-globin sequences required for stage-specific expression in transgenic mice.

The human G gamma-globin and beta-globin genes are expressed in erythroid cells at different stages of human development, and previous studies have shown that the two cloned genes are also expressed in a differential stage-specific manner in transgenic mice. The G gamma-globin gene is expressed only in murine embryonic erythroid cells, while the beta-globin gene is active only at the fetal and adult stages. In this study, we analyzed transgenic mice carrying a series of hybrid genes in which different upstream, intragenic, or downstream sequences were contributed by the beta-globin or G gamma-globin gene. We found that hybrid 5'G gamma/3'beta globin genes containing G gamma-globin sequences upstream from the initiation codon were expressed in embryonic erythroid cells at levels similar to those of an intact G gamma-globin transgene. In contrast, beta-globin upstream sequences were insufficient for expression of 5'beta/3'G gamma hybrid globin genes or a beta-globin-metallothionein fusion gene in adult erythroid cells. However, beta-globin downstream sequences, including 212 base pairs of exon III and 1,900 base pairs of 3'-flanking DNA, were able to activate a 5'G gamma/3'beta hybrid globin gene in fetal and adult erythroid cells. These experiments suggest that positive regulatory elements upstream from the G gamma-globin and downstream from the beta-globin gene are involved in the differential expression of the two genes during development.

Animals↗

Alternatives for potency testing of veterinary vaccines: rabies vaccine as a model.

Optimum information about potency of a vaccine is achieved by a protection test on the target animal species. However, application of this procedure to routine batch control requires a great number of target animals. In order to reduce the number of such animals, laboratory animal tests or in vitro tests have to be established. These tests must be correlated to target animal protection tests allowing the estimation of the vaccine potency with the same accuracy. With respect to testing the potency of rabies vaccines, alternatives are discussed, i.e. the mouse protection test, induction of antibodies in mice and in vitro tests.

Animals↗