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Biomedical subjects

G Dusheiko

Publications and source records attributed to G Dusheiko.

At least 19 recordsLinked to original sources
PubMed2004

Adefovir dipivoxil: review of a novel acyclic nucleoside analogue.

Adefovir dipivoxil (ADF) is a novel acyclic nucleoside analogue that has recently been approved for the treatment of chronic hepatitis B virus (HBV). Adefovir was initially assessed at higher doses for the treatment of human immunodeficiency virus (HIV) infection. However, in these studies, nephrotoxicity proved a dose-limiting side effect. Large randomised controlled studies have recently shown that ADF results in histological, virological and biochemical improvement in both hepatitis B e antigen (HBeAg)-positive and HBeAg-negative chronic HBV. While the rate of HBeAg seroconversion at 1 year (12%) was lower than both lamivudine and interferon, this increases with prolonged treatment. The clinical improvements occurred without serious side effects or the development of resistance at the dose of 10 mg daily, in treatment trials of up to 2 years, although resistance has now been observed. In addition, the drug is efficacious in HBV/HIV co-infection and hepatitis B-infected liver transplant recipients, particularly in those who have developed lamivudine resistance. ADF can be added as a treatment option to existing treatment options (interferon-alpha and lamivudine) and assumes a role in the ongoing management of chronic HBV. The optimal use of ADF as either a monotherapy or as part of combination therapy requires further assessment.

AIDS-Related Opportunistic Infections↗
PubMed2003

Hepatitis C and B-cell lymphoma.

The association between the hepatitis C virus and B-cell non-Hodgkin's lymphomas is controversial. We review the epidemiological evidence behind the association, and look at the reasons behind the variation in study findings. There is increasing evidence of the pathogenesis of hepatitis C-associated lymphoma. Treatment of the hepatitis C virus with antiviral therapy may lead to the regression of some low-grade lymphomas. The management of other hepatitis C-associated lymphomas is similar to that of conventional lymphoma, although viral reactivation and subsequent immune reconstitution hepatitis can complicate chemotherapy.

Hepatitis C↗
PubMed2002

The natural history and antiviral treatment of hepatitis C in haemophilia.

People with haemophilia who received non-virucidally treated large-pool clotting factor before 1986 were infected with hepatitis C virus (HCV), previously referred to as non-A, non-B hepatitis. Approximately one-tenth of patients have been shown to clear infection naturally and shown persistently negative HCV PCR. Patients have been infected with genotypes 1, 2 and 3 reflecting the plasma donors in Northern Europe and the United States. Several studies have shown that HCV mono-infection has a very slow progression. Co-infection with human immunodeficiency virus (HIV), however, can hasten the progression to cirrhosis and liver failure. Genotype 1 and older age at first infection also increase the progression rate. Candidates with detectable HCV RNA are candidates for therapy. The combination of standard interferon-alpha and ribavirin doubles the effectiveness of interferon-alpha alone and is the current standard of care for the treatment of chronic hepatitis C. The duration of therapy depends on the genotype and level of viraemia. Patients with genotypes 2 or 3 should have 6 months' therapy while those with genotype 1 and > 2 million copies mL-1 should have 1 year of therapy. Pegylated interferon is an emerging therapy. Patients co-infected with HIV, in whom treatment has stabilized the HIV infection, may be able to tolerate therapy for HCV infection. Liver transplantation is indicated for patients with haemophilia who have decompensated hepatitis C infection.

Acquired Immunodeficiency Syndrome↗
PubMed2001

The role of different immunosuppression in the long-term histological outcome of HCV reinfection after liver transplantation for HCV cirrhosis.

BACKGROUND: The effect of the type of immunosuppression on the course of posttransplant hepatitis C virus (HCV) infection is unclear. The aim of this study was to evaluate the histological outcome of posttransplant HCV infection with respect to initial immunosuppressive therapy in a cohort of 59 of 65 HCV positive transplant patients who survived at least 12 months. METHODS: Initial immunosuppressive therapy was triple (cyclosporine or tacrolimus and azathioprine and prednisolone) in 41, double (cyclosporine and prednisolone) in 5, and single (cyclosporine or tacrolimus) in 13 patients. There was blinded histological evaluation, based on necroinflammatory activity (grading score:0-18) and fibrosis (staging score: 0-6). The median histological follow-up was 36 (12-72) months. RESULTS: In the last liver biopsy, high necroinflammatory activity indicating chronic hepatitis (grading score > or =4) was found in 42 (71%) and severe fibrosis or cirrhosis (staging score > or =4) in 18 (30.5%) patients. High necroinflammatory activity was associated significantly with absence of pretransplant alcohol abuse (P=0.01) and relatively with occurrence of posttransplant acute lobular hepatitis C (P=0.055). Development of severe fibrosis or cirrhosis was significantly associated only with the type of initial immunosuppressive therapy. In particular, severe fibrosis or cirrhosis developed significantly more frequently in patients treated with triple or double (17/46 or 37%) than with single initial immunosuppressive therapy (1/13 or 7.7%) (adjusted for biopsy time: P=0.045). CONCLUSIONS: Severe fibrosis or cirrhosis appears to develop in 30% of HCV transplant patients in a median of 3 years and to be associated with heavier initial immunosuppression.

Adult↗
PubMed2001

Human CD1d-glycolipid tetramers generated by in vitro oxidative refolding chromatography.

CD1 molecules are specialized in presenting lipids to T lymphocytes, but identification and isolation of CD1-restricted lipid specific T cells has been hampered by the lack of reliable and sensitive techniques. We here report the construction of CD1d-glycolipid tetramers from fully denatured human CD1d molecules by using the technique of oxidative refolding chromatography. We demonstrate that chaperone- and foldase-assisted refolding of denatured CD1d molecules and beta(2)-microglobulin in the presence of synthetic lipids is a rapid method for the generation of functional and specific CD1d tetramers, which unlike previously published protocols ensures isolation of CD1d tetramers loaded with a single lipid species. The use of human CD1d-alpha-galactosylceramide tetramers for ex vivo staining of peripheral blood lymphocytes and intrahepatic T cells from patients with viral liver cirrhosis allowed for the first time simultaneous analysis of frequency and specificity of natural killer T cells in human clinical samples. Application of this protocol to other members of the CD1 family will provide powerful tools to investigate lipid-specific T cell immune responses in health and in disease.

Animals↗
PubMed2000

Lamivudine without HBIg for prevention of graft reinfection by hepatitis B: long-term follow-up.

BACKGROUND: This open, multicenter study was conducted to evaluate the efficacy and safety of lamivudine prophylaxis given to chronic hepatitis B virus-(HBV) infected patients before and after orthotopic liver transplantation (OLT). We now present long-term data that follow our previous short-term report. METHODS: Twenty-three patients were treated with lamivudine (100 mg orally, daily); 13 (57%), were serum HBV DNA positive (Abbott Genostics, Abbott Laboratories, Chicago, IL) at study entry. Patients received lamivudine for at least 4 weeks before OLT, and for up to 50 months (median 25 months) after OLT. RESULTS: Of the 23 treated patients, 17 survived to undergo OLT. Eleven patients (65%) survived up to 4 years (median 36 months) after OLT. One of the survivors stopped lamivudine because of a possible adverse reaction 9 months post-OLT, and prophylaxis with HBV immune globulin was then established. Ten survivors continue lamivudine. Eight long-term survivors have normal liver function without evidence of HBV reinfection. Of the 17 transplanted patients, 6 died. Four patients died (3 days to 5 months post-OLT) without evidence of graft reinfection. Two further patients died at 19 and 23 months post-OLT from graft failure. Both patients had YMDD variant detected at 12 months post-OLT. Two other patients with YMDD-variant HBV remain alive on lamivudine, 9 and 15 months after development of the variant. CONCLUSIONS: Lamivudine, given before and after OLT, prevents significant graft reinfection for the majority of treated patients. The study has also shown that lamivudine is extremely well tolerated by liver failure patients and for a prolonged period after transplantation.

Biopsy↗
PubMed2000

Why do cytotoxic T lymphocytes fail to eliminate hepatitis C virus? Lessons from studies using major histocompatibility complex class I peptide tetramers.

Hepatitis C virus (HCV) infection is a major public health problem, affecting an estimated 3% of the world's population, and over 10% in some countries. Infection in most cases becomes persistent, and can lead to hepatic inflammation, fibrosis and liver failure. The T lymphocyte reponse, in particular that mediated by cytotoxic T lymphocytes (CTLs), is likely to be involved in determining the outcome of infection, although its overall role is not clear. The use of major histocompatibility complex (MHC) class I peptide tetrameric complexes (tetramers) to study antiviral CTL responses has revolutionized our approach to the study of human infection. We have used a panel of MHC class I tetramers to analyse immune responses in HCV-infected individuals at various stages of disease. We find that the CTL response against HCV is vigorous in its early phases but dwindles over time both in terms of lymphocyte number and function. A number of potential explanations for this 'CTL failure' are discussed.

Adult↗
PubMed2000

HCV genotypes--role in pathogenesis of disease and response to therapy.

Hepatitis C virus (HCV) shows considerable variation in its genomic structure, allowing classification into six main genotypes. Epidemiological studies have shown marked differences in genotype distribution by geographical region, and between patient groups. Improved understanding of the rate of nucleotide sequence mutation in HCV has allowed the approximate time of divergence of major genotypes to be estimated, and the origin and spread of the present epidemic of hepatitis C to be better defined. Improved methods of genotype definition over the last few years have enabled the importance of genotype in the progression of HCV-related disease and response to anti-viral therapy to be studied. Present data strongly indicates that HCV genotype is an important determinant of response to treatment, but the effect of genotype on disease progression has been harder to clarify. This is largely due to the absence of model systems of HCV infection, the epidemiological differences in patient groups infected with the different genotypes, and the lack of good prospective longitudinal clinical data. As a result of advances in methodology, and recent results of large clinical trials of combination therapy, a knowledge of HCV genotype is now central to the clinician in the management of patients with chronic hepatitis C.

Antiviral Agents↗
PubMed2000

The natural history of HCV in a cohort of haemophilic patients infected between 1961 and 1985.

AIM: This study describes the long term follow up of haemophilic patients infected with hepatitis C virus (HCV) between 1961 and 1985. METHODS: Clinical and treatment records from 310 patients with inherited coagulation disorders treated with blood product before 1985 were reviewed. Standard survival analysis methods were used to model progression to liver failure and death. RESULTS: A total of 298/305 (98%) patients tested were anti-HCV positive. Twenty seven (9%) individuals consistently HCV polymerase chain reaction negative were considered to have cleared the virus. By 1 September 1999, 223/310 (72%) were alive, 26 (8%) had died a liver related death, and 61 (20%) had died from other, predominantly human immunodeficiency virus (HIV) related, causes. Kaplan-Meier progression rates to death from any cause and liver related deaths 25 years after exposure to HCV were 47% (95% confidence intervals (CI) 34-60) and 19% (95% CI 10-27), respectively. After 13.3 years from 1985, by which time all patients had seroconverted to HIV, progression rates to death from any cause and liver related deaths were, respectively, 8% (95% CI 4-13) and 3% (95% CI 0.4-6) for those HIV negative, and 57% (95% CI 48-66) and 21% (95% CI 13-31) for those HIV positive (p=0.0001). Using Cox proportional hazard models, the adjusted relative hazard of death for individuals coinfected with HIV compared with those infected with HCV alone was 19.47 (95% CI 9.22-41.10), 0.99 (95% CI 0.39-2.53), 3.47 (95% CI 1.40-8.63), and 9.74 (95% CI 3.91-24.26) for the age groups at infection 10-19 years, 20-29 years, and >30 years, respectively, compared with the age group <10 years. The adjusted relative hazard for genotype 1 compared with other genotypes was 2.7 (95% CI 1.36-5.15). CONCLUSIONS: While 25 year follow up of 310 haemophilic patients has shown the potentially lethal combination of HIV and HCV coinfection, HCV singly infected individuals show slow progression of liver disease.

Adolescent↗
PubMed1999

Long-term efficacy of treatment of chronic hepatitis C with alpha interferon or alpha interferon and ribavirin.

The major objective of treatment of chronic hepatitis C virus (HCV) infection is to prevent progression to cirrhosis, and thereby prevent complications of end-stage liver disease. The established treatment of chronic HCV is with alpha interferon. Recent results with ribavirin and alpha interferon together suggest that combination antiviral therapy will become the benchmark treatment. For both naive and relapsed patients, however, it has become important to assess the long-term outcome of treatment, in order to gauge whether treatment has indeed modified the natural history of chronic hepatitis C virus infection. It seems likely that most sustained responders (85-90%) treated with combination ribavirin and alpha interferon will continue to have a long-term biochemical and virological response, as has been demonstrated with alpha interferon alone, but further long-term follow-up of patients treated with combination therapy is required.

Antiviral Agents↗
PubMed1999

Predictors of a favorable response to alpha interferon therapy for hepatitis C.

The most consistently identified predictive factors for a response to both IFN-alpha monotherapy and IFN-alpha in combination with ribavirin are a low HCV RNA level, the absence of fibrosis, infection with HCV genotype 2 and 3, and a prolonged duration of treatment. In addition, an early response to IFN-alpha predicts response to IFN-alpha monotherapy but not necessarily to combination therapy. There does not appear to be any major gain in treating IFN-naive patients with HCV genotype 2 or 3 infection with a combination of IFN-alpha and ribavirin for longer than 6 months. The identification of these predictive factors has allowed improvement in study design and assessment and may provide a patient with an idea of the likelihood of response, making possible a more informed decision regarding treatment. At present, none of these factors, either alone or in combination, completely predicts response to IFN-alpha. Thus, individual patients should not be denied treatment on the basis of these factors.

Alanine Transaminase↗