Viral hepatitis and liver transplantation
ABSTRACT Hepatitis C is the one of the most common indications for liver transplantation. Infection of the allograft after transplantation is universal, and recurrent hepatitis C progresses at an accelerated rate. Antiviral therapy in selected patients on the transplant waiting list may reduce the rate of hepatitis C virus reinfection. Preemptive antiviral therapy after transplantation has been disappointing. However, treatment of established histological disease with a combination of pegylated interferon and ribavirin is associated with sustained virologic response rates of 25 to 40%. Significant advances have been made in the prevention of hepatitis B reinfection after transplantation. Results are now excellent, with graft infection rates less than 10%. The challenges for the future include designing strategies to optimize the use of antiviral agents to prevent the need for transplantation and to avoid antiviral resistance and to determine the dose and duration of hepatitis B immunoglobulin needed in the era of multiple nucleoside analogs.
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ABSTRACT: Hepatitis C virus (HCV) is a global public health problem that mediates a persistent infection in nearly 200 million people. HCV is efficient in establishing chronicity due in part to the inefficiency of the host immune system in controlling and counteracting HCV-mediated evasion strategies. HCV persistence is linked to the ability of the virus to suppress the RIG-I pathway and interferon production from infected hepatocytes, thus evading innate immune defenses within the infected cell. This review describes the virus and host processes that regulate the RIG-I pathway during HCV infection. An understanding of these HCV-host interactions could lead to more effective therapies for HCV designed to reactivate the host immune response following HCV infection.Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 09/2009; 29(9):489-98. DOI:10.1089/jir.2009.0063 · 3.90 Impact Factor
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ABSTRACT: Two decades ago, chronic hepatitis B virus (HBV) infection was a contraindication to liver transplantation because of graft HBV reinfection rates as high as 80%. With advances in antiviral therapy, the rate of HBV reinfection after liver transplantation has declined to less than 10%. The 5-year survival rate after transplantation increased from 53% before 1990 to 76% by 2002. Moreover, the arrival of newer antiviral therapy has expanded the treatment armamentarium before and after transplantation. With extended survival, new challenges have emerged, such as the development of antiviral resistance and the uncertain duration of hepatitis B immunoglobulin after transplantation.Current Hepatitis Reports 02/2008; 7(1). DOI:10.1007/s11901-008-0018-y
Conference Paper: Time varying lattices and autoregressive models : Parameter estimation[Show abstract] [Hide abstract]
ABSTRACT: Modeling of non-stationary signals can be achieved through time-dependent lattices and auto-regressive models. This method leads to an extension of several well-known techniques of stationary spectral estimation to the non-stationary case. Time varying AR models are identified by means of a fast Levinson algorithm, while the time-dependent reflexion coefficients of the lattice are estimated through an algorithm which is similar to Burg's. The context of these methods is off-line (blockwise) estimation.Acoustics, Speech, and Signal Processing, IEEE International Conference on ICASSP '82.; 06/1982