Antiviral therapy
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The clinical management of H5N1 influenza virus infection in humans remains unclear. Combination chemotherapy with drugs that target different viral proteins might be more effective than monotherapy. ⋯ Combination chemotherapy provided a survival advantage over single-agent treatment of mice inoculated with neurotropic H5N1 influenza virus. This strategy might be an option for the control of pandemic influenza viruses that are sensitive to amantadine. Combinations that include other drugs should be explored.
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Oseltamivir phosphate is a prodrug of oseltamivir carboxylate, a highly specific inhibitor of influenza virus neuraminidases. Given that oseltamivir carboxylate binds to highly conserved, essential amino acids in the catalytic site of the enzyme, and that the activity of neuraminidase is critical for virus release from infected cells and subsequent virus spread, the drug was expected to have a low propensity to select for viable resistant mutants. Indeed, viruses with neuraminidase (and haemagglutinin) substitutions conferring reduced susceptibility to oseltamivir have been generated with difficulty in vitro, and these mutants generally have reduced infectivity and transmissibility compared with wild-type virus in animal models. ⋯ Higher incidences of resistance were observed in two small Japanese studies, in which children received a different dosing schedule from their Western counterparts. In summary, the overall incidence of influenza virus resistance associated with the seasonal use of oseltamivir is currently low and resistant viruses might be of little clinical significance, except perhaps in immunocompromised individuals. However, continued vigilance, especially of emerging avian H5N1 strains, combined with careful, systematic laboratory-based monitoring, is essential.
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Highly pathogenic H5N1 influenza viruses have become endemic in poultry populations throughout Southeast Asia and continue to infect humans with a greater than 50% case fatality rate. So far, human-to-human transmission of these viruses has been limited. Here, we discuss the molecular features of H5N1 influenza viruses that might affect their pathogenicity, and explain the current lack of efficient human-to-human transmission. Such knowledge is critical in evaluating the pandemic risk these viruses pose.
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A wide range of viruses affect the respiratory tract of transplant recipients, including adenovirus, influenza, human metapneumovirus, parainfluenza virus, respiratory syncytial virus (RSV) and rhinovirus. Prospective studies using contemporary diagnostic techniques have recently improved our understanding of the epidemiology and importance of these respiratory viruses among transplant recipients. From these studies, rhinovirus, in particular, has been shown to be one of the most common causes of infection in stem cell and lung transplant recipients. In addition to epidemiological data, recent studies have also advanced our understanding of management of influenza, adenovirus, and RSV infections among transplant recipients.
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Comparative Study Clinical Trial
The influence of HIV infection and antiretroviral therapy on the mitochondrial membrane potential of peripheral mononuclear cells.
Clinical disorders occurring in HIV-infected patients on antiretroviral therapy (ART) have been linked to mitochondrial dysfunction, for example, lactic acidosis and lipodystrophy. Mitochondrial membrane potential (delta psi m) is the most direct measure of the state of energization of the mitochondria. We analysed delta psi m, of peripheral blood mononuclear cells (PBMCs) in HIV-negative, healthy subjects (n=8), HIV-infected, treatment-naive patients (n=30), and HIV-infected patients on ART (n=58). The influence of ART was analysed in six patients who started their first regimen. ⋯ In HIV-infected persons delta psi m is significantly reduced. Patients with lipoatrophy have significantly reduced delta psi m. This is the first study showing that the delta psi m of PBMCs is highly correlated with CD4+ T-cell count in HIV infection.