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Biomedical subjects

E Thiry

Publications and source records attributed to E Thiry.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparative pathogenesis of acute and latent infections of calves with bovine herpesvirus types 1 and 5.

This study was conducted to compare the pathogenesis of acute and latent infections with closely related bovine herpesvirus types 1 (BHV-1) and 5 (BHV-5) in their natural host. Two groups of eight calves were inoculated intranasally with BHV-1 or BHV-5. Although BHV-1 and BHV-5 similarly replicate in the nasal mucosa after inoculation, both viruses differ markedly in their ability to cause disease, BHV-5 being responsible of some fatal encephalitis while BHV-1 inducing rhinotracheitis. Virus isolation and immunohistochemistry demonstrated that BHV-5 replicates extensively in neurons of the central nervous system (CNS) and in respiratory cells of lungs, tracheal and nasal mucosae. Invasion of the CNS likely occurs through the trigeminal and olfactory pathways. Both groups developed cross-neutralising antibodies during this experiment suggesting partial clinical cross-protection afforded by the two infections. Three months after primary infection, experimental reactivation showed that BHV-5 was able to establish latency in the trigeminal ganglia but also the CNS of surviving calves. Moreover, laboratory findings suggested that BHV-5 could also persist in the tracheal and nasal mucosae. These results indicate that, after primary infection, BHV-1 and BHV-5 displayed similar biological features and consequently need to be considered together for the control of BHV-1 infection.

Acute Disease↗
PubMed2001

Use of PCR and immunofluorescence to detect bovine herpesvirus 1 recombinants.

Homologous recombination occurs frequently between strains of the same alphaherpesvirus species. Studies of this phenomenon require techniques that can differentiate parental strains from putative recombinant progeny viruses. Usually, progeny viruses generated by co-infection of two distinguishable parental strains are first cloned by selection of a single plaque and then characterised by PCR. An assay designed to investigate recombination between two bovine herpesvirus 1 (BHV-1) strains lacking either the glycoprotein gC or gE ORF is described. A PCR assay was developed in which a single step co-amplifies both BHV-1 glycoprotein-encoding sequences. Because the usual procedure for virus isolation, viral plaque picking, can lead to polyclonal virus preparations, a PCR protocol alone does not differentiate between samples containing recombinant viruses (gC+/gE+) and those containing a mixture of both single deleted parental strains (gC-/gE+ and gC+/gE-), and false positives resulting from recombination could occur. To reduce this possibility, double-label immunofluorescence staining of isolated plaques was developed, which coupled with PCR, allows straightforward discrimination between parental strains and progeny recombinant viruses. This assay will be useful for further studies of recombination, especially those evaluating the potential emergence of recombinants between BHV-1 marker vaccine and wildtype strains.

Animals↗
PubMed2000

Specific passive immunity reduces the excretion of glycoprotein E-negative bovine herpesvirus type 1 vaccine strain in calves.

We investigated the excretion of either a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BHV1) vaccine strain or a conventional modified-live vaccine strain in both naïve and passively immunised calves. The replication of gE-negative strain was considerably reduced in the maternally immunised calves, in comparison with the non-immune calves. On the other hand, the excretion of the gE-positive conventional vaccine strain was not reduced and even seemed to be prolonged in the presence of maternal antibodies. These results suggest that BHV1 gE may play a role in virus survival in the presence of antibodies.

Animals↗
PubMed2000

A multipotential beta -1,6-N-acetylglucosaminyl-transferase is encoded by bovine herpesvirus type 4.

The beta-1,6-N-acetylglucosaminyltransferase (beta1,6GnT) gene family encodes enzymes playing crucial roles in glycan synthesis. Important changes in beta1,6GnT expression are observed during development, oncogenesis, and immunodeficiency. The most characterized beta1,6GnTs in this gene family are the human (h) C2GnT-L and h-IGnT, which have core 2 [Galbeta1-->3(GlcNAcbeta1-->6)GalNAc] and I branching [GlcNAcbeta1-->3(GlcNAcbeta1-->6)Gal] activities, respectively. Recently, h-C2GnT-M was shown to be unique in forming core 2, core 4 [GlcNAcbeta1-->3(GlcNAcbeta1-->6)GalNAc], and I structures. To date, the beta1,6GnT gene family has been characterized only in mammals. Here, we describe that bovine herpesvirus type 4 (BHV-4) encodes a beta1,6GnT expressed during viral replication and exhibiting all of the core 2, core 4, and I branching activities. Sequencing of the BHV-4 genome revealed an ORF, hereafter called BORFF3-4, encoding a protein (pBORFF3-4) exhibiting 81.1%, 50.7%, and 36.6% amino acid identity with h-C2GnT-M, h-C2GnT-L, and h-IGnT, respectively. Reverse transcriptase-PCR analysis revealed that BORFF3-4 is expressed during BHV-4 replication. Expression of BORFF3-4 in Chinese hamster ovary cells directed the expression of core 2 branched oligosaccharides and I antigenic structures on the cell surface. Moreover, a soluble form of pBORFF3-4 had core 4 branching activity in addition to core 2 and I branching activities. Finally, infection of a C2GnT-negative cell line with BHV-4 induced expression of core 2 branched oligosaccharides. This study extends the beta1,6GnT gene family to a viral gene and provides a model to study the biological functions of a beta1,6GnT in the context of viral infection.

Amino Acid Sequence↗
PubMed2000

Production of bovine herpesvirus type 1-seronegative latent carriers by administration of a live-attenuated vaccine in passively immunized calves.

The consequences of the vaccination of neonatal calves with the widely used live-attenuated temperature-sensitive (ts) bovine herpesvirus type 1 (BHV-1) were investigated. The ts strain established acute and latent infections in all vaccinated calves either with or without passive immunity. Four of seven calves vaccinated under passive immunity became clearly BHV-1 seronegative by different serological tests, as did uninfected control calves after the disappearance of maternal antibodies, and they remained so for long periods. A cell-mediated immune response was detected by a BHV-1 gamma interferon assay, but this test failed to detect the seronegative latent carriers (SNLCs). While they are not detected, SNLCs represent a threat for BHV-1-free herds or countries. This study demonstrates that SNLCs can be easily obtained by inoculation with a live-attenuated BHV-1 under passive immunity and that latent carrier animals without any antibody do exist. Consequently, this situation could represent a good model to experimentally produce SNLCs.

Animals↗
PubMed2000

Effects of bovine herpesvirus type 1 infection in calves with maternal antibodies on immune response and virus latency.

The presence of maternally derived antibodies can interfere with the development of an active antibody response to antigen. Infection of seven passively immunized young calves with a virulent strain of bovine herpesvirus type 1 (BHV-1) was performed to determine whether they could become seronegative after the disappearance of maternal antibodies while latently infected with BHV-1. Four uninfected calves were controls. All calves were monitored serologically for 13 to 18 months. In addition, the development of a cell-mediated immune response was assessed by an in vitro antigen-specific gamma interferon (IFN-gamma) production assay. All calves had positive IFN-gamma responses as early as 7 days until at least 10 weeks after infection. However, no antibody rise was observed after infection in the three calves with the highest titers of maternal antibodies. One of the three became seronegative by virus neutralization test at 7 months of age like the control animals. This calf presented negative IFN-gamma results at the same time and was classified seronegative by enzyme-linked immunosorbent assay at around 10 months of age. This calf was latently infected, as proven by virus reexcretion after dexamethasone treatment at the end of the experiment. In conclusion, this study demonstrated that BHV-1-seronegative latent carriers can be obtained experimentally. In addition, the IFN-gamma assay was able to discriminate calves possessing only passively acquired antibodies from those latently infected by BHV-1, but it could not detect seronegative latent carriers. The failure to easily detect such animals presents an epidemiological threat for the control of BHV-1 infection.

Aging↗
PubMed2000

[Professional civil responsibility of physicians: towards a modification of the law in the year 2000?].

For more than twenty years, physicians, lawyers, insurers and patients stress the wrong working of civil medical liability in our country. After surveying the most important slacknesses of the current system, the author examines the answers or proposals on the one hand of the jurisprudence and on the other hand of the governing authorities and finally of the scientific sector. The study emphasizes also the current community of interest which leads to implementation of a new law which content is however difficult to define. At last, the author tries to show the most clearly expected modifications and suggests also some practical pieces of advice regarding the evolution of the jurisprudence.

Belgium↗
PubMed1999

Channel catfish virus gene 50 encodes a secreted, mucin-like glycoprotein.

Cells infected with the wild-type (WT) strain of channel catfish virus (CCV) secreted a glycoprotein with an apparent molecular mass (MM) superior to 200 kDa into the culture medium. This protein, designated gp250, was the sole viral glycoprotein detected in the culture medium after [3H]mannose labeling of the infected cells. When cells were infected with the attenuated V60 strain, a glycoprotein of 135 kDa (designated gp135) was detected instead of gp250. Because WT gene 50 is predicted to encode a secreted, mucin-type glycoprotein, we expressed this gene transiently and detected a glycoprotein of the same apparent MM as gp250 in the culture medium of transfected catfish cells. The increased mobility in SDS-PAGE of the secreted V60 glycoprotein correlated with the presence of a major deletion in V60 gene 50. Therefore, we concluded that gp250 in the WT and gp135 in the V60 strains are both likely encoded by gene 50. An important shift in the relative mobility of gp250 in SDS-PAGE was observed after tunicamycin treatment of infected cells labeled with [3H]glucosamine, confirming the presence of N-linked sugars on gp250. We observed variations in the size of PCR products derived from gene 50 amplification in three different field isolates. Such genetic variations are a characteristic feature of mucin genes and are linked to crossing-over events between internal repeated sequences, such as those present in gene 50.

Animals↗
PubMed1999

A specific PCR to differentiate between gE negative vaccine and wildtype bovine herpesvirus type 1 strains.

In the context of infectious bovine rhinotracheitis (IBR) control programmes using glycoprotein E (gE) deleted marker vaccines, a PCR assay was developed to allow the genotypic differentiation between wildtype bovine herpesvirus type 1 (BoHV-1) and gE negative strains. This assay is based on the PCR amplification of a 281 bp DNA fragment within the gE gene. The specificity of the amplification was confirmed by restriction endonuclease analysis and nucleotide sequencing of the PCR product. Its ability to determine the gE genotype of BoHV-1 strains was demonstrated on isolates coming from 20 experimental calves infected with four different BoHV-1 strains. This PCR assay may be a useful tool for monitoring the spread of live marker vaccine and the gE genotype of viral field isolates.

Animals↗
PubMed1999

Antibody response to glycoprotein E after bovine herpesvirus type 1 infection in passively immunised, glycoprotein E-negative calves.

This study was conducted to determine whether young calves with maternal antibodies against bovine herpesvirus type 1 (BHV-1) but without antibodies against glycoprotein E (gE) can produce an active antibody response to gE after a BHV-1 infection. Five calves received at birth colostrum from gE-seronegative cows which had been vaccinated two or three times with an inactivated BHV-1, gE-deleted marker vaccine. After inoculation with a wild-type virulent strain of BHV-1, all the passively immunised gE-negative calves shed virus in large amounts in their nasal secretions. All the calves seroconverted to gE within two to four weeks after inoculation and then had high levels of gE antibodies for at least four months. The development of an active cell-mediated immune response was also detected by in vitro BHV-1-specific interferon-gamma assays. All the calves were latently infected, because one of them re-excreted the virus spontaneously and the other four did so after being treated with dexamethasone. The results showed that under the conditions of this work the gE-negative marker could also distinguish between passively immunised and latently infected calves.

Animals↗
PubMed1999

Association between coding variability in the LRP gene and the risk of late-onset Alzheimer's disease.

We have sequenced the entire (89 exons) open reading frame of the LRP gene in 12 cases of Alzheimer's disease (AD) from Northern France. We have found no novel changes but confirm the occurrence of a polymorphism in exon 6 of the gene (A216V). This polymorphism is rare (2.8% of controls) and is in linkage equilibrium with previously reported polymorphisms. The V216 allele is negatively associated with the disease in a large case-controlled series. These data suggest that the LRP receptor may be involved in the pathobiology of AD, but the association that we report here cannot explain the previously reported genetic data implicating the LRP gene in AD. If the LRP gene is a major site of genetic variability leading to AD, there must be other biologically relevant variability in promoter or other regulatory elements of this large gene.

Aged↗
PubMed1999

Identification and characterization of bovine herpesvirus type 5 glycoprotein H gene and gene products.

Bovine herpesvirus type 5 (BHV-5) is the causative agent of a fatal meningo-encephalitis in calves and is closely related to BHV-1 which causes infectious bovine rhinotracheitis. The gene encoding BHV-5 glycoprotein gH was sequenced. A high degree of conservation was found between BHV-1 and BHV-5 deduced gH amino acid sequences (86. 4%), which is also observed for all alphaherpesvirus gH sequences. Transcriptional analysis revealed a 3.1 kb mRNA as the specific gH transcript which was detected 2 h post-infection (p.i.). Twelve out of twenty-one MAbs directed against BHV-1 gH immunoprecipitated a 108-110 kDa glycoprotein, which was then designated BHV-5 gH. Synthesis and intracellular processing of BHV- 5 gH was analysed in infected MDBK cells using gH cross-reacting MAbs. Glycoprotein gH was expressed as a beta-gamma protein, detected by radioimmunoprecipitation as early as 3 h p.i. Glycosylation studies indicated that BHV-5 gH contains N-linked carbohydrates which are essential for the recognition of the protein by the MAbs. This suggests that N-linked glycans are involved in protein folding or are targets for the gH cross-reacting MAbs. Plaque- reduction neutralization assays showed that at least one BHV-1 gH antigenic domain is lacking in BHV-5 which may possibly relate to in vivo differences in virus tropism.

Alphaherpesvirinae↗
PubMed1999

[The rights of patients--medical concerns].

The protection of patients rights is neither a new concern nor a limited to Belgium one. The study shows that, at all times, the doctors have been worried about the necessity of respect of the patients. This respect is inherent to the confidence patients have in the doctors. The study also explains that the policy framework on the rights of the patients has been developed in the world and in particular, in Europe, after World War II. In a third part, the belgian legislative initiatives are commented according to the opinions of famous legal writers. Finally, the study emphasizes the fact that it is necessary to stimulate dialogue-structures for doctors and patients and that we have to avoid too rigid rules.

Belgium↗
PubMed1998

Strategy to sequence the 89 exons of the human LRP1 gene coding for the lipoprotein receptor related protein: identification of one expressed mutation among 48 polymorphisms.

The human lipoprotein receptor related protein (LRP) binds and internalizes a diverse set of ligands, making LRP the most multifunctional endocytic receptor known. This is possible due to the large size, i.e., 600 kDa, of the receptor protein containing three clusters of putative ligand binding domains, each structurally comparable to the classical LDL receptor. Based on previous structural analysis of the human LRP1 gene (Van Leuven et al., 1994, Genomics, 24: 78-89), a strategy was developed to sequence the 89 exons of the LRP1 gene, including partial intron sequences. The gene was amplified from individual genomic DNA by long-range PCR, in 14 amplicons sized between 0.4 and 11 kb that were used as templates for 110 sequencing primers. In total, 48 mutations and intronic polymorphisms were identified. Two previously reported polymorphisms, i.e., in the promoter region and in exon 3, were precisely defined by sequencing. The first expressed mutation, i.e., an alanine to valine transition at position 217 of the LRP precursor protein, was detected on one allele in 2 of 33 individuals. Although the strategy is still subject to refinement, this approach is reported to allow others to analyze genetic differences in the human LRP1 gene, with particular reference to the recently reported association with late-onset Alzheimer disease.

Contig Mapping↗
PubMed1998

Analysis of the human LRPAP1 gene coding for the lipoprotein receptor-associated protein: identification of 22 polymorphisms and one mutation.

The lipoprotein receptor-associated protein (RAP) is considered a chaperone protein for the lipoprotein receptor-related protein (LRP) and for the other members of the LDL receptor family. Genetic analysis is anticipated to help in delineating groups or individuals with potential defects or problems in this regard. A combined amplification/sequencing strategy was developed to analyze the human LRPAP1 gene for polymorphisms and mutations. The LRPAP1 gene was amplified from genomic DNA in four long-range PCR amplicons, 2.4 to 7.6 kb in size. Three amplicons were finally used as templates with 14 sequencing primers to obtain the sequence of the eight exons and large portions of adjacent introns from individual DNA. This strategy, applied to sequence the LRPAP1 gene of 14 unrelated, normal individuals revealed, in total, 23 distinct mutations and polymorphisms, mostly intronic substitutions and deletions. In this small group 1 expressed mutation was encountered on one allele in 2 unrelated individuals: a G to A transition results in the replacement of valine by methionine in exon 7 at position 311 of the human RAP precursor protein.

Amino Acid Substitution↗
PubMed1998

An association exists between bovine herpesvirus-4 seropositivity and abortion in cows.

The prevalence of cattle seropositive to bovine herpesvirus-4 (BHV-4) is high in Belgium. In Belgian farms, clinical signs associated with BHV-4 infection essentially involve the genital tract and consist mainly of postpartum metritis or metroperitonitis. The role of BHV-4 in abortion has not been definitively demonstrated but epidemiological and experimental facts suggest its involvement. A seroepidemiological investigation was therefore conducted as a case-control study to compare the seroprevalences of BHV-4 infections in the aborted-cow population and in a randomly selected control group in the province of Liège (Belgium). The seroprevalence (17.2%) in aborted cows was significantly higher than that of the control group (10.0%). The odds ratio (OR) was 1.87 (1.06 < 3.30). BHV-4 infection is therefore considered as a risk factor for abortion in cows.

Abortion, Veterinary↗
PubMed1998

Virulence, immunogenicity and reactivation of bovine herpesvirus 1 mutants with a deletion in the gC, gG, gI, gE, or in both the gI and gE gene.

Within the framework of developing a marker vaccine against bovine herpesvirus 1 (BHV1), several mutants with deletions in non-essential glycoprotein genes were constructed. Glycoprotein gC, gG, gI and gE single deletion mutants, a gI/gE double deletion mutant and a gE frame-shift mutant were made. The virulence and immunogenicity of these mutants were evaluated in specific-pathogen-free calves. Except for the gC deletion mutant, all mutants were significantly less virulent than the parental wild-type (wt) BHV1 strain Lam. The virulence of the gI and the gI-/gE- mutants was almost completely reduced. Upon challenge infection, the calves of the control group became severely ill, whereas all other calves remained healthy. The reduction of the virus shedding after challenge infection was related to the virulence of the strain of primary inoculation. Virus shedding was almost completely reduced in calves first inoculated with Lam-wt or with gC- and the least reduced in calves inoculated with gI- or gI-/gE-. Six weeks after challenge, all calves were treated with dexamethasone to study whether mutant or challenge virus or both could be reactivated. The gC- and the gG- mutants were reactivated, whereas none of the other mutants were reisolated. Reactivation of challenge virus was reduced in all calves inoculated with mutant viruses. The gC deletion mutant was too virulent and the gI and the gI/gE deletion mutants were the least immunogenic, but based on residual virulence and immunogenicity, both the gG and the gE deletion mutants are candidates for incorporation in live BHV1 vaccines. However, it also depends on the kinetics of the anti-gG and anti-gE antibody response after wild-type virus infection, whether these deletion mutants are really suitable to be incorporated in a marker vaccine.

Animals↗