Showing results 121 to 140 of 209
 Flow cytometric method for the detection of gpI antigens of varicella zoster virus and evaluation of anti-VZV agents; ; Sadzot-Delvaux, Catherine  et alin Journal of Virological Methods (1992), 38(2), 243-254 Varicella zoster virus (VZV) is responsible for a primary infection (varicella.) and, upon reactivation, zoster, which in immunocompromised patients, may both lead to life-threatening disseminated disease ... [more ▼] Varicella zoster virus (VZV) is responsible for a primary infection (varicella.) and, upon reactivation, zoster, which in immunocompromised patients, may both lead to life-threatening disseminated disease. There is a great need for antiviral compounds that are effective inhibitors of VZV replication and for rapid and accurate methods for evaluating viral sensitivity to candidate anti-VZV drugs. With the monoclonal antibody (mAb) (VL8), which is directed against the gpI of VZV, and using the fluorescence-activated cell sorter (FACS) we could readily demonstrate expression of the VZV gpI antigen at 3-4 days after VZV infection. (E)-5-(2-Bromovinyl)-2'-deoxyuridine (BVDU), (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA) and (S)-1-(3-hydro-xy-2-phosphonylmethoxypropyl)cytosine (HPMC) were shown to be potent inhibitors of VZV replication by this assay. HPMPA and HPMPC were also active against thymidine kinase-deficient (TK-) VZV whereas BVDU was not. The flow cytometric method based on the use of mAb VL8 may be of considerable help for the early diagnosis of VZV infection and evaluation of viral sensitivity to antiviral drugs. [less ▲] Detailed reference viewed: 8 (0 ULg)High-rate of multiple genital HPV infections detected by DNA hybridization; Piette, Jacques ; Lifrange, Eric et alin Journal of Medical Virology (1992), 36(4), 265-270 Cervical smears collected from 450 patients involved in a clinical follow-up of cervical human papillomaviruses (HPV) infections were screened for the presence of HPV 6b, 11, 16, and 18 DNA by both dot ... [more ▼] Cervical smears collected from 450 patients involved in a clinical follow-up of cervical human papillomaviruses (HPV) infections were screened for the presence of HPV 6b, 11, 16, and 18 DNA by both dot blot and southern blot hybridization methods. Using very high stringency hybridization assays, the four HPV types could be easily distinguished by dot blotting. After a preliminary clinical sorting, 42.9% of the samples were found to be HPV-positive. Among the samples infected by a single HPV, type 16 was the most frequent (25.4% of the positive samples) followed by 6b (19.7%), 11 (8.3%), and 18 (7.2%). Double or even multiple infections by the different HPV types were detected at a very high rate (39.4% of the positive samples). [less ▲] Detailed reference viewed: 8 (0 ULg)Etude ultrastructure de l'organisation du nucléoïde du virus de la varicelle et du zona; Piette, Jacques ; Rentier, Bernard in Bulletin de la Société Royale des Sciences de Liège (1992), 60(6), 373-383 Detailed reference viewed: 13 (0 ULg)Human papillomavirus type 33 upstream regulatory elements can control gene expression in human cervical keratinocytes; Rentier, Bernard ; Piette, Jacques in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100 Detailed reference viewed: 4 (2 ULg)La régulation de l'expression des gènes du virus de la varicelle et du zonaPiette, Jacques ; ; et alin Annales de Médecine Vétérinaire (1992), 136(8), 627-635 Varicella-zoster virus (VZV) belongs to the alphaherpesvirus family and shares many important structural and functional similarities with other members of the family such as herpes simplex virus type 1 ... [more ▼] Varicella-zoster virus (VZV) belongs to the alphaherpesvirus family and shares many important structural and functional similarities with other members of the family such as herpes simplex virus type 1 (HSV-1). VZV is responsible for two different clinical syndromes, varicella which is the result of the primary infection and zoster which is due to virus reactivation remaining latent in the peripheral nervous system. VZV DNA is 124,884 base pair long and encodes four regulatory proteins (IE4, IE61, IE62 and IE63). Using transient expression systems, we have shown that IE4, IE62 and IE63 can regulate the expression of an indicator gene driven by various VZV promoter regions, demonstrating that these proteins play important roles in the infectious cycle. [less ▲] Detailed reference viewed: 21 (0 ULg) Antibodies to varicella-zoster virus modulate antigen distribution but fail to induce viral persistence in vitro.Sadzot-Delvaux, Catherine ; ; et alin Journal of Virology (1992), 66(12), 7499-504 Varicella-zoster virus (VZV) persists in human sensory ganglia. One of the hypotheses to explain the induction or the maintenance of VZV latency is that it could be promoted by the immune response itself ... [more ▼] Varicella-zoster virus (VZV) persists in human sensory ganglia. One of the hypotheses to explain the induction or the maintenance of VZV latency is that it could be promoted by the immune response itself. It is known that in the case of viruses which bud off the infected cell membrane, virus-specific antibodies can induce antigenic modulation, i.e., spatial redistribution of viral antigens and modulation of their synthesis. To determine whether antigenic modulation occurs during VZV infection in vitro and could possibly be involved in viral persistence, we have grown infected cells in the presence of anti-VZV antibodies either transiently or permanently. The distribution of immune complexes and viral proteins was then analyzed. In transient immunomodulation experiments, the distribution of one or more viral antigens was modified not only in the cytoplasmic membranes but also in the cytoplasm and nucleoplasm of infected cells. When infected cells were kept permanently in the presence of antibodies, the same pattern of redistribution of immune complexes was observed and the localization of internal viral glycoproteins was significantly modified. However, antibodies did not prevent the lytic effect of infection; they altered neither the infectious virus yield nor the Western immunoblot pattern of viral proteins, suggesting that immunomodulation is not the primary effector of viral persistence. [less ▲] Detailed reference viewed: 17 (8 ULg)Restriction endonuclease patterns of HSV-1 and HSV-2 DNA isolated from 2 patients with relapsing episodesSadzot-Delvaux, Catherine ; Vaira, Dolorès ; et alPoster (1992) Detailed reference viewed: 14 (2 ULg)Two-dimensional study of varicella-zoster virus proteins; Duquesne, Patricia ; Sadzot-Delvaux, Catherine et alPoster (1992) Detailed reference viewed: 3 (1 ULg)Granulomatous reactions following herpes-zoster contain varicella-zoster glycoprotein GPINikkels, Arjen ; Sadzot-Delvaux, Catherine ; et alin Journal of Investigative Dermatology (1992), 98(4), 522 Detailed reference viewed: 7 (1 ULg)Characterization of regulatory functions of the varicella-zoster virus gene-63-encoded proteinJackers, Pascale ; ; et alin Journal of Virology (1992), 66(6), 3899-3903 Varicella-zoster virus (VZV) gene 63 encodes a protein (IE63) with a predicted molecular mass of 30.5 kDa which has amino acid similarities to the immediate-early (IE) protein 22 (ICP22) of herpes simplex ... [more ▼] Varicella-zoster virus (VZV) gene 63 encodes a protein (IE63) with a predicted molecular mass of 30.5 kDa which has amino acid similarities to the immediate-early (IE) protein 22 (ICP22) of herpes simplex virus type 1. ICP22 is a polypeptide synthesized in herpes simplex virus type 1-infected cells, and as is the case for its VZV counterpart, its regulatory functions are unknown. On the basis of the VZV DNA sequence, it has been shown that IE63 exhibits hydrophilic and acidic properties, suggesting that this protein could play a regulatory role during the infectious cycle. We report in this article cotransfection experiments which demonstrate that the VZV gene 63 protein strongly represses, in a dose-dependent manner, the expression of VZV gene 62. On the other hand, transient expression of the VZV gene 63 protein can promote activation of the thymidine kinase gene but cannot affect the expression of the genes encoding glycoproteins I and II. The results of transient expression experiments strongly suggest that the VZV gene 63 protein could play a pivotal role in the repression of IE gene expression as well as in the activation of early gene expression [less ▲] Detailed reference viewed: 37 (20 ULg)Varicella-zoster gene 63 encoded protein is an important regulatory factorJackers, Pascale ; ; et alin Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100 Detailed reference viewed: 22 (7 ULg)Study of a new presumed mitochondrial carrier, the product of the yeast RIM 2 gene; ; Duyckaerts, Claire et alin Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100 Detailed reference viewed: 14 (1 ULg)HIV-1 reactivation after an oxidative stressLegrand, Sylvie ; Vaira, Dolorès ; Rentier, Bernard et alin LinkVIII International Conference on AIDS/III STD World Congress, Amsterdam, the Netherlands 19-24 July 1992 (1992) OBJECTIVES: A common denominator shared by several HIV-1 reactivation agents such as certain cytokines, UV irradiation and heat shock is their ability to cause stress response. Consequently, we have ... [more ▼] OBJECTIVES: A common denominator shared by several HIV-1 reactivation agents such as certain cytokines, UV irradiation and heat shock is their ability to cause stress response. Consequently, we have investigated the effects of oxidative stress on HIV-1 reactivation, knowing that HIV-1 latently infected T cells can be exposed in vivo to such a stress when blood phagocytes are stimulated during inflammatory reactions. METHODS: The promonocytic (U1) and lymphocytic (ACH-2) cell lines, both HIV-1 chronically infected, were used to study the reactivation phenomenon. To test wether HIV-1 reactivation is mediated by LTR transactivation, the HeLa HIV-1 CAT cell line, which carries an integrated DNA cartridge containing CAT gene under control of HIV-1 LTR, was also exposed to an oxidative stress. RESULTS: Hydrogen peroxide exposure of U1 cells leads to an increased reverse transcriptase (RT) activity in supernatant fluid. Over the optimal concentrations range (0.5 to 1 mM), a four to fivefold stimulation level is reached. Below these concentrations, stress conditions are not sufficient and above, they induce a too important lethal effect. Immunofluorescence carried out on stressed U1 cells shows that H2O2 leads to HIV-1 gene expression activation and not to a release of viral particles from damaged cells. H2O2 also induces a stimulation of CAT activity in HeLa HIV-1 CAT cells. Intracellular singulet oxygen (1O2) is also able to induce an increase of RT activity in supernatant fluid of U1 and ACH-2 cells and a stimulation of CAT activity in HeLa HIV-1 CAT cells. A dose-response curve can also be demonstrated. In order to transpose these in vitro experiments to situations encountered in vivo, activated phagocytes were cocultivated with HeLa HIV-1 CAT cells. A weak stimulation of CAT activity was detected. CONCLUSIONS: Cellular oxidative damages induce HIV-1 LTR transactivation leading to viral gene expression and consequently to a burst of virus production. DNA damages induced by oxidative stress could be at the onset of HIV-1 reactivation. Experiments are now in progress to elucidate the mechanisms leading to HIV-1 reactivation after an oxidative stress. [less ▲] Detailed reference viewed: 15 (2 ULg)HIV-1 reactivation after an oxidative stressLegrand, Sylvie ; Hoebeke, Maryse ; Vaira, Dolorès et alin Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100 Detailed reference viewed: 9 (5 ULg)Varicella-zoster virus: an ultrastructural study of the assembly phases; Piette, Jacques ; Rentier, Bernard in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100 Detailed reference viewed: 5 (1 ULg)Two-dimensional study of varicella-zoster virus proteins; ; et al in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100(2), 39 Detailed reference viewed: 10 (2 ULg)Molecular characterization of varicella-zoster virus gene expression; ; Jackers, Pascale et alin Archives Internationales de Physiologie, de Biochimie et de Biophysique (1992), 100 Detailed reference viewed: 8 (2 ULg)VZV glycoproteins gpI and gpII are present in dermal cells without their corresponding genomeNikkels, Arjen ; Delvenne, Philippe ; et alin Journal of Cutaneous Pathology (1992), 19 Detailed reference viewed: 10 (3 ULg)Detection by PCR of varicella zoster virus DNA during primary infection in mice; Sadzot-Delvaux, Catherine ; et alin Archives Internationales de Physiologie et de Biochimie (1992), 100 Detailed reference viewed: 22 (17 ULg)Parasite communities: Patterns and ProcessesRentier, Bernard in Book Reviews, Biochemical Systematics and Ecology (G. Esch, A. Bush & J. Aho, eds., Chapman & Hall, 1990) (1991) Detailed reference viewed: 29 (2 ULg) |
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