Abstract 5-Ethyl-2′-deoxyurldine (EDU) is phosphorylated to a much greater extent by herpes simplex virus (HSV)-infected Vero cells than by mock-infected cells. Within the infected cells, EDU is preferentially incorporated into viral DNA and more inhibitory to viral than cellular DNA synthesis
The destruction of the immune system by progressive loss of CD4 T cells is the hallmark of AIDS. CCR5-dependent (R5) human immunodeficiency virus type 1 (HIV-1) isolates predominate in the early, asymptomatic stages of HIV-1 infection, while CXCR4-dependent (X4) isolates typically emerge at later stages, frequently coinciding with a rapid decline in CD4 T cells. Lymphocyte killing in vivo primarily occurs through apoptosis, but the importance of apoptosis of HIV-1-infected cells relative to apoptosis of uninfected bystander cells is controversial. Here we show that in human lymphoid tissues ex vivo, apoptosis of uninfected bystander CD4 T cells is a major mechanism of lymphocyte depletion caused by X4 HIV-1 strains but is only a minor mechanism of depletion by R5 strains. Further, X4 HIV-1-induced bystander apoptosis requires the interaction of the viral envelope glycoprotein gp120 with the CXCR4 coreceptor on CD4 T cells. These results emphasize the contribution of bystander apoptosis to HIV-1 cytotoxicity and suggest that in association with a coreceptor switch in HIV disease, T-cell killing evolves from an infection-restricted stage to generalized toxicity that involves a high degree of bystander apoptosis.
Antiviral therapy and, particularly, anti-HIV therapy has definitely come of age [1]. There are now more than 30 compounds that have been formally approved for the therapy of virus infections. The nucleoside reverse transcriptase inhibitors (NRTIs) zidovudine, didanosine, zalcitabine, stavudine, lamivudine and abacavir are used in the treatment of human immunodeficiency virus (HIV) infections and lamivudine is also licensed for the treatment of hepatitis B virus (HBV) infections. The nucleotide reverse transcriptase inhibitor (NtRTI) tenofovir has been approved for the treatment of HIV infections and is also effective againstHBVinfections. The non-nucleoside reverse transcriptase inhibitors (NNRTIs) nevirapine, delavirdine and efavirenz are exclusively used in the treatment of HIV infections, and so are the HIV protease inhibitors (PIs) saquinavir, ritonavir, indinavir, nelfinavir, amprenavir and lopinavir.
Le but de cette etude est d'analyser les performances des differentes sources laser disponibles pour le frittage selectif direct au laser des poudres metalliques sans aucun liant polymere. Pour cela, on a fritte des pieces bidimensionnelles (c'est-a-dire en une seule couche) de differents melanges de poudres acier-cuivre; et les differentes proprietes de ces pieces ont ete analysees. Dans cet article, on a compare en detail le laser Nd:YAG avec le laser Co 2 . On a pu en conclure que le laser Nd:YAG donnait de meilleurs resultats que le laser Co 2 pour le frittage direct en phase liquide de pieces en acier-cuivre.
An experimental model of herpetic infection based on intranasal challenge of 12-day-old mice with herpes simplex virus (type 1) has been developed for assessment of the efficacy of a variety of antiviral compounds with clinical potential: cytosine arabinoside, adenine arabinoside, iododeoxyuridine, ribavirin, chloriteoxidized oxyamylose, polyriboinosinic-polyribocytidylic acid, and interferon. The model employed is reminiscent of herpetic encephalitis in humans in both the portal of entry (nasopharyngeal cavity) and the mode of transmission (nerve route) of the virus to the target organ (brain). The mortality rate from viral infection was significantly reduced (greater than or equal to 30%) by the following treatment regimens: cytosine arabinoside, adenine arabinoside, iododeoxyuridine, and ribavirin, administered daily for seven consecutive days starting immediately after inoculation of virus, at dosage levels of 4-20 mg/kg, 20-100mg/kg, 100mg/kg, and 20-100 mg/kg, respectively; and chlorite-oxidized oxyamylose, polyriboinosinic-polyribocytidylic acid, and mouse interferon, administered 24 hr before viral challenge, as single doses of 100-500 mg/kg, 20mg/kg, and 10(7)-10(8) international reference units/kg respectively. Similar doses of polyriboinosinic-polyribocytidylic acid and mouse interferon administered after inoculation of virus did not alter the final mortality rate.
SUMMARY Various double-stranded RNAs of either synthetic or natural origin have been compared for their interferon-inducing potency in human skin fibroblasts ‘primed’ with interferon and ‘superinduced’ with cycloheximide and actinomycin D. While natural double-stranded RNAs (extracted from either Penicillium chrysogenum mycophage, f2 bacteriophage or reovirus) and alternating copolymers [(A-U)n.(A-U)n, (G-C)n.(G-C)n, (I-C)n.(I-C)n]* proved relatively less effective in inducing interferon than (I)n.(C)n, a variety of synthetic homopolymer pairs, including (I)n.(br5C)n, (I)n.(s2C)n, (A)n.(rT)n and (A)n.(U)n, showed an interferon-inducing activity comparable to that of (I)n.(C)n.
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