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Biomedical subjects

R Hoff-Jørgensen

Publications and source records attributed to R Hoff-Jørgensen.

10 recordsLinked to original sources
PubMed1997

Examination of virus shedding in semen from vaccinated and from previously infected boars after experimental challenge with porcine reproductive and respiratory syndrome virus.

Danish artificial insemination (AI) centres house several boars antibody positive to porcine reproductive and respiratory syndrome virus as well as PRRSV-naive boars which may become acutely infected. The risk of transmission of PRRSV by semen may therefore constitute a serious problem to the Danish pig industry. The use of a vaccination-program may be a way to avoid or reduce the problem. This study evaluates the use of two vaccines: One live, attenuated vaccine and one inactivated vaccine. A pronounced reduction in viremia and shedding of virus in semen was demonstrated by use of the live vaccine compared to the non-vaccinated control animals. In contrast, no changes in onset, level and duration of viremia and shedding of virus in semen were observed using the inactivated vaccine. Neither viremia nor seminal shedding of virus was detected in previously PRRSV-infected, PRRSV-antibody positive boars after challenge with a Danish field strain of PRRSV.

Animals↗
PubMed1994

Combined polymerase chain reaction-hybridization microplate assay used to detect bovine leukemia virus and Salmonella.

Here we describe the use of an assay that integrates the polymerase chain reaction (PCR) with hybridization of the amplified product for detection in the same microwell. Traditional PCR requires transportation of the amplified product to another system for characterization of samples. Transportation means time-consuming manipulation and risk of contaminating the laboratory with amplified product. Integration of amplification and specific product detection greatly reduces sample manipulations and the risk of contamination. We used the assay for detection of bovine leukemia virus and Salmonella. The results were identical with those produced by two traditional PCR methods. This assay could easily be adapted for other organisms, simply by using other primers and probes.

Base Sequence↗
PubMed1991

Demonstration of antibodies against bovine leukemia virus (BLV) by blocking ELISA using bovine polyclonal anti-BLV immunoglobulin.

A blocking enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against bovine leukemia virus (BLV) is described. The test is based on the biotin-streptavidin system using unlabelled polyclonal bovine IgG against BLV as catching antibody and biotinylated bovine anti-BLV IgG as detecting antibody. The sensitivity was found to be 50-100 times higher than the agar gel immunodiffusion test, with a specificity of practically 100%. The blocking ELISA proved to be suitable for detection of antibodies against BLV in serum and milk. In 34 paired milk/serum samples, the average ratio of BLV antibody titres was 1:26. So far, more than 700,000 sera have been screened by blocking ELISA for BLV antibodies in the course of the Danish surveillance programme for BLV infection.

Animals↗
PubMed1990

Antibody reactivity against animal retroviruses in multiple sclerosis.

A total of 27 MS patients and 82 controls were studied for presence of antibodies reacting with maedi-visna virus and bovine leukemia virus by means of 2 ELISA techniques. Furthermore, the differentiated antibody response against BLV antigens was evaluated by immunoblotting. People with elevated activities against MVV were detected in the MS group as well as controls. Elevated antibody activity against BLV as determined by biotinylated protein A and peroxidase-labelled streptavidin tended to occur more frequently in MS patients than in controls. No such difference was found, however, when peroxidase-conjugated antibodies against human kappa chain were used for detection of antibodies reacting with BLV. Immunoblotting revealed no difference between the MS and the control group when anti-kappa antibodies were used to detect antibody binding to BLV antigens. The protein A method revealed significantly decreased antibody activity against a BLV antigen with molecular weight of about 29 kD in MS compared with controls, whereas a significant rise in number of MS patients responding to a component of about 53 kD was observed. The differences between the 2 detection systems could be due to unspecific reactions. The present data indicate that MS patients exhibit an inhomogeneous and, in some cases elevated, antibody activity against BLV.

Adult↗
PubMed1990

Detection by enzyme-linked immunosorbent assay of Aujeszky's disease virus in tissues of infected pigs.

An enzyme-linked immunosorbent assay was developed for the detection of Aujeszky's disease virus antigen in tissue extracts and in nasal swabs. The enzyme-linked immunosorbent assay is based on two different monoclonal antibodies with specificity for the gII glycoprotein of Aujeszky's disease virus. Viral antigen was detected in 81 of 93 tissue extracts prepared from virus-infected organs. Fifteen outbreaks of Aujeszky's disease were analyzed in this study, and they were all identified by the gII antigen enzyme-linked immunosorbent assay.

Animals↗
PubMed1990

Diagnosis of enzootic bovine leucosis in single and pooled samples.

Diagnosis of enzootic bovine leucosis is based on detection of antibodies against bovine leukemia virus, BLV. Some ELISA modifications have proved sensitive enough for use in the examination of pooled blood samples from slaughterhouses, milk and pooled milk samples. Suggestions for the standardisation of different ELISA modifications using a common reference serum are presented.

Animals↗
PubMed1989

An international comparison of different laboratory tests for the diagnosis of bovine leukosis: suggestions for international standardization.

A collaborative study was conducted to compare the detection limit of different laboratory tests for antibodies against bovine leukemia virus (BLV). Serum and milk samples were tested in agar gel immunodiffusion (AGID), different modifications of indirect ELISA, blocking ELISA and ELISA procedures using monoclonal antibodies to BLV gp51 or BLV p24. The detection limit of reference serum E4 diluted 2-fold in negative serum gave a median value of 1:16 in AGID, indirect ELISA, and monoclonal ELISA p24, 1:128 in monoclonal ELISA gp51, and 1:1024 in blocking ELISA. The detection limit of a 4% immunoglobulin preparation of E4 diluted in negative milk showed median values of 1:800 in indirect ELISA, 1:1000 in monoclonal ELISA, and 1:2400 in blocking ELISA. None of the ELISA procedures could detect all the positive individual milk samples diluted 1:50. The AGID test is the official reference test for detection of antibodies against BLV. Reference serum E4 diluted 1:10 in negative serum must be scored positive in the AGID test. It is suggested that an international reference serum standard be established rather than an official recommendation of a particular ELISA test.

Animals↗
PubMedDate not supplied

Testing blood plasma from cattle in leukosos-free herds for antibodies against bovine leukemia virus (BLV).

As a prelude to the introduction of serological methods in the Danish leukosis eradication programme, an examination for antibody to Bovine Leukemia Virus (BLV) was carried out in 215 randomly selected leukosis-free herds in three areas where 3 routine haematological screening tests had bee made over a period of 6 years. A gel diffusion test was applied to plasma samples. Of 3319 animals screened, none were found to have detectable levels of antibody to BLV in their plasma. This would seem to indicate that false positive reactions are not a serious problem in connection with this test, and also that herds classified as leukosis-free after a series of haematological herd tests carried out within a period of some years, are in fact free from infection with Bovine Leukemia Virus.

Animals↗