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Biomedical subjects

J F Mornex

Publications and source records attributed to J F Mornex.

At least 37 records · Page 2Linked to original sources
PubMed1998

Defective RNA packaging is responsible for low transduction efficiency of CAEV-based vectors.

Replication defective retroviral vectors are regularly used for transfer and expression of exogenous genes into dividing cells and in animals. Since lentiviruses are able to infect terminally differentiated and non-dividing cells, their use to produce replication defective vectors may overcome this limitation. We developed two replication-defective lentiviral vectors based on the genome of Caprine Arthritis Encephalitis Virus (CAEV). The first vector (pBNL2) carries the neo and lacZ marker genes. Neo gene is expressed from a genomic RNA and lacZ gene from a subgenomic RNA. The second vector (pCSHL) carries a single fusion gene encoding both phleomycin resistance and beta-galactosidase activity. Replication-competent CAEV was used as helper virus to provide the viral proteins for transcomplementation of these vectors. Our data demonstrated that the genomes of both vectors were packaged into CAEV virions and transduced into goat synovial membrane cells following infection. However, the vector titers remained 3 to 4 logs lower than those of CAEV. Further analysis showed a lack of accumulation of unspliced pBNL2 RNA into the cytoplasm of producer cells resulting in the packaging of pBNL2 sub-genomic RNA only. In contrast, RNA produced from pCSHL vector was correctly transported to the cytoplasm and more efficiently packaged than the pBNL2 sub-genomic RNA as revealed by slot-blot and quantitative RT/PCR analyses. However this higher packaging efficiency of pCSHL genome did not result in a higher transduction efficiency of lacZ gene.

Animals↗
PubMed1998

Self-expanding metal stents for the management of bronchial stenosis and bronchomalacia after lung transplantation.

BACKGROUND: Airway stenosis or malacia after lung transplantation, usually as a result of anastomotic ischemia, remains a major problem. METHODS: The authors report their experience with the Gianturco expandable stent for the management of 23 bronchial stenoses in 18 patients following lung transplantation. Stent placement occurred an average of 5.6 months after transplantation. RESULTS: Stents were well tolerated and produced immediate symptomatic and functional improvement. The mean follow-up after implantation was 21 months (range, 4 to 48 mo). The authors removed five stents by endoscopy and replaced them, and removed one stent entirely. Laser resection was used to control granulomas or partial fibrosis stenosis that occurred in four stents (14.3%) after an average of 4 months. One stent broke but was still in place and effective 32 months later. One patient died of hemorrhage 4 months after stenting. CONCLUSION: Although it can still be improved, this expandable metal stent is suitable for the treatment of posttransplantation proximal bronchial stenosis.

Adult↗
PubMed1998

Visna-maedi virus induces interleukin-8 in sheep alveolar macrophages through a tyrosine-kinase signaling pathway.

The mechanisms leading to the severe lung damage seen in some sheep naturally infected with the visna-maedi virus, and to pulmonary lesions in other lentiviral diseases, appear to involve the recruitment of large numbers of uninfected inflammatory cells. Only a few alveolar macrophages from experimentally infected lambs express virus, but high levels of interleukin (IL)-8 mRNA are present in the macrophage population. In vitro infection with visna-maedi virus at low multiplicity of alveolar macrophages from uninfected sheep also strongly induced the expression of IL-8 mRNA and the accumulation of IL-8 in the extracellular medium. An initial peak of IL-8 mRNA expression at 3 or 6 h after infection was followed by a fall, then a more persistent expression lasting at least 48 h after infection. The early peak was accompanied by expression of mRNA for IL-1beta, and a possible rise in tumor necrosis factor alpha (TNFalpha) mRNA, although this was frequently elevated in uninfected ovine alveolar macrophages. Interestingly, these events occurred identically in cells treated with non-infectious heat-treated virus, suggesting that interaction between viral components and cellular membrane receptors could suffice for both early and late IL-8 induction. The level of IL-8 mRNA induced by treatment with live or inactivated virus could be severely reduced by pretreatment of the macrophages with genistein but not with staurosporine, suggesting the involvement of a tyrosine-kinase signaling pathway. The early induction of IL-1beta and possibly of TNFalpha may explain the occurrence of a later persistent expression of IL-8 mRNA through an autocrine mechanism.

Animals↗
PubMed1998

[Pleuro-peritoneal Denver shunt in treatment of chronic pleurisy].

The first utilisation in our hospital of a pleuraperitoneal shunt for the treatment of chronic pleurisy enabled us to study, in the light of published data, the place for such a procedure in the management of resistant pleural effusion. The aetiology of the pleurisy in a 70-year old patient who underwent this mini-invasive surgery was unknown when the shunt was inserted, but his symtoms clearly improved afterwards. At the present time with a follow-up of 13 months, there are no local complications and the system is in good working order. In 1982, the material used for the first time in such a case was an adapted version of Denver's peritoneal venous shunt. This is composed of a pleural catheter linked by a pump that the patient controls himself, to a peritoneal catheter. This pump can be inserted under local anaesthetic. The principal indications in the literature, in which the series do not exceed 70 cases are: malignant pleurisy where it is preferable to introducing tale in the case of tissue retraction fastening to the underlying lung and also in chylous pleurisy, especially those secondary to congenital east disease in children. A complication rate of 25% is noted depending on the type of infection or obstruction leading to replacement of the shunt. No case of erosion has been noted. The long term patency, measured by radio-isotope injections (Tc99m), has not been studied but there is a significant reduction in the length of hospital stay which gives a clear economic advantage to such procedures.

Aged↗
PubMed1997

[Organ graft: indications and principle results in France].

Nearly 3,000 solid organ transplantations are performed each year in France. Transplantation constitutes a major and complex treatment procedure which mostly concerns patients with terminal organ failure. The selection of patients to transplant, amongst those with potential indications for transplantation, contributes to improve the whole results of transplantation. The evaluation of transplantation deals with transplants and patients survival as well as quality of life after transplantation which may be assessed by organ function improvement, professional activity restoration or pregnancy eventuality in transplanted women.

Evaluation Studies as Topic↗
PubMed1997

Alveolar macrophages from sheep naturally infected by visna-maedi virus contribute to IL-8 production in the lung.

Sheep naturally infected by visna-maedi virus often develop a chronic interstitial lung disease characterized by an alveolitis comprising lymphocytes, neutrophils and macrophages. The alpha chemokine interleukin-8 (IL-8) was detected in cell free bronchoalveolar lavage fluid from naturally infected animals, confirmed by RT-PCR, presenting typical lesions of maedi and elevated total alveolar cell counts. No detectable IL-8 was found in the fluid obtained from uninfected animals. IL-8 concentration in alveolar fluid is correlated with alveolar neutrophil counts. Bronchoalveolar lavage cells from infected animals were found to contain a large amount of IL-8 mRNA and may contribute to IL-8 production. In situ hybridization showed that macrophages were the predominant cell type expressing IL-8 mRNA. Sustained production of IL-8 by alveolar macrophages during visna-maedi infection could suffice for neutrophil attraction to the alveoli, and may contribute to the development of lesions.

Animals↗
PubMed1997

Genomic heterogeneity of small ruminant lentiviruses: existence of heterogeneous populations in sheep and of the same lentiviral genotypes in sheep and goats.

We have recently shown that French small ruminant lentiviruses (SRLV) from sheep are more similar to Caprine Arthritis Encephalitis Virus (CAEV) than to visna maedi virus (VMV) in a conserved region of the pol gene. To extend these results, we have examined sequences from a variable region of the env gene in French SRLV. We found that they were nearly equally distant from both CAEV and VMV strains, suggesting a considerable divergence since the initial introduction of the virus. Analysis of separate clones from individual animals showed that some carry a population of variant viruses. The study of further pol gene sequences from both goats and sheep suggests that viral variants show little or no host species specificity. A phylogenetic tree of pol gene sequences confirmed the presence of a novel genotype of SRLV in France.

Amino Acid Sequence↗
PubMed1997

T-lymphocyte populations in the blood of caprine arthritis encephalitis virus-infected goats.

The effect of natural infection by Caprine Arthritis Encephalitis Virus on the phenotypic pattern of T lymphocytes in peripheral blood was studied in a herd of 127 milking goats by flow cytometry. Total leukocyte and T-lymphocyte numbers tend to decrease with age, with only small changes in the CD4/CD8 ratio. The lymphocyte phenotypes show no strong correlation with seropositivity to CAEV or the presence of clinical symptoms, suggesting that this macrophagetropic lentivirus does not greatly effect the lymphocyte population.

Animals↗
PubMed1997

Presence of a unique parainfluenza virus 3 strain identified by RT-PCR in visna-maedi virus infected sheep.

The presence in farm sheep of a paramyxovirus closely related to parainfluenza virus type 3 (Pi3) from humans or cattle was confirmed using RT-PCR on RNA samples from lung cells from slaughtered animals. Sequencing and restriction enzyme patterns of the amplified fragment of the F gene confirms the distinctness of the isolate, and suitable PCR primers allow specific detection of the ovine virus. A study of the incidence of ovine Pi3 in samples from sheep with or without distinctive histopathological signs of maedi shows that it is uncommon in aged sheep with overt lentiviral disease, but it occurs at moderate frequency in lambs and may, in the presence of visna-maedi virus, contribute to early lesion formation.

Abattoirs↗
PubMed1997

Intracellular thiopurine nucleotides and azathioprine myelotoxicity in organ transplant patients.

AIMS: Despite widespread use of azathioprine in organ transplant recipients, the mechanism of its myelotoxicity remains unclear. The aim of this study was to assess the importance of thiopurine metabolites on bone marrow toxicity. METHODS: We investigated the relationship between intracellular concentrations of 6-thioguanine (6-TGN), 6-mercaptopurine (6-MPN) and 6-thioxanthine (6 TXN) nucleotides and the absolute count of white or red cells in forty-seven lung or heart/lung transplant patients after oral administration of azathioprine. RESULTS: No significant correlation between red cell concentrations of 6-TGN or total thiopurine metabolites and white or red cell counts was found, with no difference between the sexes. Likewise, high 6-TGN levels were not related to bone marrow depletion. CONCLUSIONS: These results suggest that red blood cell 6-TGN alone do not predict the haematopoietic toxicity of azathioprine.

Adolescent↗
PubMed1997

dUTPase-minus caprine arthritis-encephalitis virus is attenuated for pathogenesis and accumulates G-to-A substitutions.

The importance of the virally encoded dUTPase for CAEV replication, invasiveness, pathogenesis, and genetic stability was investigated in goats infected by viruses with single point (DU-G) and deletion (DU-1) mutations of the dUTPase gene (DU gene). The DU gene was found to be dispensable for CAEV replication in vivo as judged by times taken to seroconvert, frequencies of viral isolation, and tissue distribution of viral RNAs. DU- reversion at week 34 in one of three goats infected with the single point mutant DU-G, however, suggested that the viral dUTPase confers some advantages for replication in vivo. Moreover, we show that dUTPase is necessary for the timely development of bilateral arthritic lesions of the carpus. Finally, dUTPase was shown to efficiently prevent accumulation of G-to-A transitions in the viral genome.

Animals↗
PubMed1997

Early diagnosis of lentivirus-induced infiltrative lung disease in sheep by high resolution computed tomography.

The visna-maedi lentivirus can induce an interstitial pneumonitis in sheep, and provides a convenient example to study natural or experimental lentiviral pathology. We wanted to determine whether high resolution computed tomography (HRCT) is able to detect early morphological changes following lentiviral infection in the lungs. Spontaneously infected adult sheep (n=3) and experimentally infected lambs (n=5) were compared to uninfected controls (n=4). The HRCT scans generally showed abnormal features in infected animals, including: increased parenchymal density; alveolar oedema; thickened interlobular septa; and increased density in peribronchiolar areas. HRCT was more sensitive than chest radiography for the early diagnosis of interstitial pneumonitis, although one sheep with advanced disease and radiographic and histopathological abnormalities had a paradoxically normal scan. One control animal showed minor abnormalities on scanning, which were probably due to the procedure used for anaesthesia. The HRCT observations were confirmed by postmortem histological examination of the lungs. In conclusion, high resolution computed tomography provides a noninvasive means of following the development of lung pathology in a natural ovine model of lentiviral disease.

Animals↗
PubMed1997

RT-PCR detection of lentiviruses in milk or mammary secretions of sheep or goats from infected flocks.

In this study we evaluated a reverse transcriptase polymerase chain reaction (RT-PCR) technique for detecting lentiviral infection in milk or mammary secretions from small ruminants. Initial observations on seven goats infected with cloned caprine arthritis-encephalitis virus (CAEV) showed that RT-PCR on milk cells is as reliable as coculture for detecting viral infection, and is quicker and simpler. With a suitable choice of redundant primers followed by a semi-nested amplification, it proved possible to detect the virus in milk samples from naturally infected French sheep (8/8) or goats (9/9), and viral sub-groups could be identified by hybridization with discriminatory probes. All seropositive animals gave positive amplifications, as did one seronegative goat from a contaminated herd, suggesting greater sensitivity for RT-PCR. None of eight goats from a long-established seronegative herd ever gave a positive RT-PCR amplification. This technique provides a simple means for rapidly identifying potentially infectious animals and for epidemiological investigations, as long as the primers are selected according to the genetic structure of the local viral population.

Animals↗
PubMed1997

Immortalization of caprine fibroblasts permissive for replication of small ruminant lentiviruses.

OBJECTIVE: To establish immortalized caprine fibroblastic cell lines permissive for replication of small ruminant lentiviruses. ANIMALS: Carpal synovial membrane explants collected aseptically from a surgically delivered fetus of a lentivirus-seronegative goat. PROCEDURE: Immortalization of goat embryonic fibroblasts was performed by DNA transfection with plasmids coding for simian virus 40 large T antigen. The generated cell lines were phenotypically characterized. Cytogenetics, growth pattern, and sensitivity to viral infection were studied. RESULTS: 3 cell lines, designated TIGEF, mMTSV-54, and mMTSV-93, were generated. They had a more rapid doubling time than did fibroblasts from which they were derived, and retained morphologic and phenotypic fibroblastic characteristics. They were immortalized but not transformed because tumor formation was not promoted after their s.c. injection into athymic nude mice. The 3 cell lines were susceptible to caprine arthritis-encephalitis virus and visna-maedi virus infections, and supported a complete virus replication cycle. CONCLUSIONS: Cultured caprine fibroblastic cells were immortalized, using simian virus 40 large T antigen. The TIGEF, mMTSV-54, and mMTSV-93 immortalized cell lines were permissive to in vitro small ruminant lentivirus replication. CLINICAL RELEVANCE: Because lentivirus detection, as well as detailed studies of host-lentivirus interactions, are hampered by differences in viral susceptibility of each primary culture, permanent cell lines are essential tools for such analysis.

Animals↗