Drugs online research references
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Acyclovir is an acyclic guanine analog with a considerable activity against herpes simplex viruses. We studied the antiherpetic activity of acyclovir in macrophages and fibroblast cell lines. Utilising a plaque reduction assay we found that acyclovir potently inhibited the HSV-1 replication in macrophages (EC50) = 0.0025 microM) compared to Vero (EC50 = 8.5 microM) and MRC-5 (EC50 = 3.3 microM) cells. The cytotoxicity of acyclovir was not detected at concentrations < or = 20 microM, thus the selective index in macrophages was >8000. This marked difference in antiherpetic activity between macrophages and fibroblasts was not observed with Foscarnet and PMEA. We suggest that this potent antiviral effect of acyclovir is mainly due to a proficient phosphorylation of the drug and/or a favourable dGTP/acyclovir triphosphate ratio in macrophage cells.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11521752&dopt=Abstract
J Virol. 2001 Nov;75(22):11178-84.
Gamma interferon can prevent herpes simplex virus type 1 reactivation from latency in sensory neurons.
Liu T, Khanna KM, Carriere BN, Hendricks RL.
Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213-2588, USA.
We recently demonstrated that CD8(+) T cells could block herpes simplex virus type 1 (HSV-1) reactivation from latency in ex vivo trigeminal ganglion (TG) cultures without destroying the infected neurons. Here we establish that CD8(+) T-cell prevention of HSV-1 reactivation from latency is mediated at least in part by gamma interferon (IFN-gamma). We demonstrate that IFN-gamma was produced in ex vivo cultures of dissociated latently infected TG by CD8(+) T cells that were present in the TG at the time of excision. Depletion of CD8(+) T cells or neutralization of IFN-gamma significantly enhanced the rate of HSV-1 reactivation from latency in TG cultures. When TG cultures were treated with acyclovir for 4 days to insure uniform latency, supplementation with recombinant IFN-gamma blocked HSV-1 reactivation in 80% of cultures when endogenous CD8(+) T cells were present and significantly reduced and delayed HSV-1 reactivation when CD8(+) T cells or CD45(+) cells were depleted from the TG cultures. The effectiveness of recombinant IFN-gamma in blocking HSV-1 reactivation was lost when its addition to TG cultures was delayed by more than 24 h after acyclovir removal. We propose that when the intrinsic ability of neurons to inhibit HSV-1 gene expression is compromised, HSV-specific CD8(+) T cells are rapidly mobilized to produce IFN-gamma and perhaps other antiviral cytokines that block the viral replication cycle and maintain the viral genome in a latent state.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11602757&dopt=Abstract
Nucl Med Biol. 2000 Feb;27(2):157-62.
Synthesis of 8-[(18)F]fluoroguanine derivatives: in vivo probes for imaging gene expression with positron emission tomography.
Namavari M, Barrio JR, Toyokuni T, Gambhir SS, Cherry SR, Herschman HR, Phelps ME, Satyamurthy1 N.
Division of Nuclear Medicine, Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, California 90095-6948, USA.
A new method for the preparation of 8-[(18)F]fluoroguanine derivatives based on a direct radiofluorination reaction has been developed. The radiofluorination of ganciclovir (1a) with [(18)F]F(2) was carried out in absolute ethanol in the presence of tetraethylammonium hydroxide at room temperature to give 8-[(18)F]fluoroganciclovir (3a) in an approximately 1% radiochemical yield. Similarly, 8-[(18)F]fluoropenciclovir (3b), 8-[(18)F]fluoroacyclovir (3c), and 8-[(18)F]fluoroguanosine (3d) were synthesized from penciclovir (1b), acyclovir (1c), and guanosine (1d), respectively, using [(18)F]F(2). The structural analyses of the final products (3a, 3b, 3c, and 3d) were carried out after (18)F decay by (1)H, (13)C, and (19)F nuclear magnetic resonance and high resolution mass spectroscopy.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10773544&dopt=Abstract
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