PubMed Health⌕ Search

Biomedical subjects

N Boyer

Publications and source records attributed to N Boyer.

At least 19 recordsLinked to original sources
PubMed2006

Quantitative measurement of hepatitis C virus core antigen is affected by the presence of cryoglobulins.

Mixed cryoglobulinaemia is associated strikingly with HCV infection. The aim of this study was to assess whether the adherence to proper methods of collecting samples for cryoglobulin detection was critical or not on virological parameters in hepatitis C virus (HCV) patients. We studied 56 consecutive patients. Blood samples were collected using a conventional method and a blood collection method at 37 degrees C adapted to cryoglobulin detection. HCV core antigen and HCV RNA were measured in sera and cryoglobulins issued from both blood collection methods. In cryoglobulin-positive patients, serum concentrations of HCV core antigen, but not that of HCV RNA, were significantly higher when a conventional method was used, compared to a blood collection method at 37 degrees C (P = 0.001). In the cryoprecipitates, concentration of HCV core antigen was optimum when the blood collection method at 37 degrees C, rather than the conventional method, was applied for cryoglobulin detection (P < 10(-4)). The recovery of HCV core antigen in the cryoprecipitate was improved when cryoglobulins were isolated using the blood collection method at 37 degrees C rather than the conventional method (P < 0.001). HCV parameter measurements and cryoglobulin study should not be performed on the same serum samples due to the potential impact of blood collection methods on results.

Blood Specimen Collection↗
PubMed2006

Accurate model predicting sustained response at week 4 of therapy with pegylated interferon with ribavirin in patients with chronic hepatitis C.

Current models used to predict response to peginterferon plus ribavirin treatment, based on viral decline during the first 12 weeks of therapy, have focused on creating an early stopping rule to avoid unnecessary prolongation of therapy. We developed a multivariate model that predicted sustained virological response and nonresponse at baseline and during the first 12 weeks of therapy using collected data from 186 unselected patients with chronic hepatitis C treated with peginterferon plus ribavirin. This model employed ordinal regression with similarity least squares technology to assign the probability of a given outcome. Model variables include sex, age, prior treatment status, genotype, baseline serum alanine aminotransferase levels, histologic necroinflammation and fibrosis scores and serum hepatitis C virus RNA concentration at baseline and weeks, 4, 8, and 12. A multivariate model demonstrated high performance values at all time points. At baseline, the model demonstrated a negative predictive value (NPV) and a positive predictive value (PPV) of 91% and 95%, respectively. At week 4, these values improved to 97% and 100%, respectively, with 95% sensitivity, 89% specificity and 93% accuracy. At week 4, the model was equally efficient for naïve or previously treated patients. Internal validation demonstrated 90% PPV, 94% NPV, 95% sensitivity, 88% specificity and 92% accuracy. A week 4 stopping rule for patients with chronic hepatitis C treated with peginterferon with ribavirin might be proposed by using the model developed in our study.

Adult↗
PubMed2006

Medical therapy of patients affected by HBeAg-negative chronic hepatitis B.

Five agents are currently approved for the treatment of chronic hepatitis B: standard interferon-alpha (IFN-alpha), pegylated interferon-alpha 2a (PEG-IFN-alpha 2a), lamivudine, adefovir and entecavir. Each agent has inherent limitations. IFN and PEG-IFN-alpha 2a are effective in a minority of patients and have frequent side effects that limit their tolerability. The efficacy of lamivudine is limited by the emergence of drug-resistant hepatitis B virus (HBV) mutants, restricting its utility as a long-term therapy. Adefovir is well tolerated and associated with a low incidence of resistance but its antiviral effect is not optimal. Entecavir, which has been recently registered, has a more potent anti-viral effect but its long term efficacy and resistance profile is still not known. These antivirals induce a sustained response after withdrawal of therapy in only a minority of patients and therefore the treatment needs to be indefinitely administered in the majority of patients. After a brief summary of the natural history of chronic hepatitis B in order to understand the indications and the objectives of therapy, this review focuses on treatment of HBeAg-negative chronic hepatitis B with IFN and PEG-IFN-alpha 2a.

Adenine↗
PubMed2005

Treatment of chronic hepatitis B.

In the last years, marked progress has been made in the treatment of chronic hepatitis B. The efficacy of lamivudine, the first nucleoside analogue available, is limited by the high incidence of resistance. Adefovir, which was recently approved has a comparable efficacy with a very low frequency of resistance. However, adefovir needs to be indefinitely administered as withdrawal of therapy is generally associated with reactivation and sustained response is uncommon. Recent large randomized controlled trials showed that PEG IFNs induce relatively high sustained response rates both in HBeAg positive and HBeAg negative chronic hepatitis B. So far, the combination of PEG IFN with lamivudine, used simultaneously, is disappointing in terms of short-term efficacy. However, long-term efficacy needs to be assessed and different schedules of combination (for example sequential) need to be evaluated. A number of nucleoside analogues, with favourable toxicity profiles and a promise of increased effectiveness against HBV, are at various stages of clinical development. Results of phase III trials of entecavir and emtricitabine confirmed their efficacy. However, while entecavir is associated with a low incidences of resistance, emtricitabine is associated with a relatively high incidence of resistance which limits its use as a monotherapy. The efficacy and safety of new and more potent drugs like telbivudine and clevudine need to be confirmed. The future of chronic hepatitis B therapy seems to be in the combination of different drugs. Ideally, the optimal drugs to combine would meet the following criteria: they should have different sites of action on HBV DNA replication, a potent antiviral effect, an excellent safety profile and they should induce a sustained response with a limited duration of therapy. Indeed, the concept of combination therapy has been recently developed in order to increase efficacy and to decrease the occurrence of viral resistance. However, so far few combinations have been evaluated. No combination therapy demonstrated a benefit as compared with monotherapy. More potent drugs and new combinations together with the understanding of the mechanisms of resistance to therapy are important challenges to improve the efficacy of treatment and decrease in the future the global burden related to chronic hepatitis B.

Animals↗
PubMed2005

Safety and efficacy of peginterferon plus ribavirin in patients with chronic hepatitis C and bridging fibrosis or cirrhosis.

The combination of pegylated interferon and ribavirin is the most effective therapy in patients with chronic hepatitis C. We evaluated this combination in unselected patients with bridging fibrosis or cirrhosis. Eighty patients were treated with peginterferon alpha-2b plus ribavirin. Hepatitis C virus serum RNA was monitored. Tolerance and safety were evaluated by the rate of treatment's discontinuation for any reason, and occurrence of serious clinical adverse events, respectively. Sustained virologic response (SVR) rate was 36.3% overall, and was observed in every group of patients except those who had previously failed to respond to the combination of interferon and ribavirin. No serious clinical adverse event occurred. Treatment was withdrawn in 18.7% of patients. Variables associated with discontinuation of treatment were low prothrombin index [OR: 1.16 (1.05;1.27)] and low body mass index [OR: 1.47 (1.12;1.92)]. Initial blood count abnormalities were not associated with cessation of treatment. Furthermore, early virologic response at week 8 and week 12 of treatment had similar predictive value for SVR. Combination therapy with peginterferon plus ribavirin seems effective in this group of patients, except in those who had previously failed to respond to the combination of interferon and ribavirin. This therapy is safe with appropriate monitoring, but tolerance seems worse in patients with the most advanced liver disease.

Adult↗
PubMed2005

Natural history of hepatitis B.

The natural course of hepatitis B virus (HBV) chronic infection is variable, ranging from an inactive HBsAg carrier state to a more or less progressive chronic hepatitis, potentially evolving to cirrhosis and hepatocellular carcinoma (HCC). Chronic hepatitis may present as typical HBeAg-positive chronic hepatitis B or HBeAg-negative chronic hepatitis B. HBeAg-positive chronic hepatitis is due to wild type HBV; it represents the early phase of chronic HBV infection. HBeAg-negative chronic hepatitis is due to a naturally occurring HBV variant with mutations in the precore or/and basic core promoter regions of the genome; it represents a late phase of chronic HBV infection. The latter form of the disease has been recognized as increasing in many countries within the last decade and it represents the majority of cases in many countries. HBeAg-negative chronic hepatitis B is generally associated with a more severe liver disease with a very low rate of spontaneous disease remission and a low sustained response rate to antiviral therapy. Longitudinal studies of patients with chronic hepatitis B indicate that, after diagnosis, the 5-year cumulative incidence of developing cirrhosis ranges from 8-20%. Morbidity and mortality in chronic hepatitis B are linked to evolution to cirrhosis or HCC. The 5-year cumulative incidence of hepatic decompensation is approximately 20%. The 5-year probability of survival is approximately 80-86% in patients with compensated cirrhosis. Patients with decompensated cirrhosis have a poor prognosis (14-35% probability of survival at 5 years). HBV-related end-stage liver disease or HCC are responsible for at least 500,000 deaths per year.

Adolescent↗
PubMed2004

Long term clinical outcome of chronic hepatitis C patients with sustained virological response to interferon monotherapy.

BACKGROUND: The key end point for treatment efficacy in chronic hepatitis C is absence of detectable virus at six months after treatment. However, the incidence of clinical events during long term follow up of patients with sustained virological response is still poorly documented and may differ between the Eastern and Western world. AIMS: To assess clinical end points during long term follow up of European patients with a sustained virological response to interferon monotherapy. METHODS: Meta-analysis of individual patient data from eight European protocolled follow up studies of interferon treatment for chronic hepatitis C. RESULTS: A total of 286 sustained virological responders and 50 biochemical responders (detectable virus but normal alanine aminotransferase levels) were followed up for 59 months. Fifteen sustained virological responders (5.2%) had cirrhosis before treatment and 112 (39%) had genotype 1. The late virological relapse rate after five years of follow up was 4.7% (95% confidence interval (CI) 2.0-7.4) among sustained virological responders; all late relapses occurred within four years after treatment. Among sustained virological responders, the rate of decompensation after five years of follow up was 1.0% (95% CI 0.0-2.3) and none developed hepatocellular carcinoma (HCC). Survival was comparable with the general population, matched for age and sex, the standard mortality ratio being 1.4 (95% CI 0.3-2.5). Clinical outcome of patients with cirrhosis was similar to other sustained virological responders. For biochemical responders, the rates of development of decompensation and HCC during long term follow up were 9.1% (95% CI 0.5-17.7) and 7.1% (95% CI 0-15.0), respectively. CONCLUSIONS: Five year survival of European sustained virological responders was similar to the overall population, matched for age and sex. No HCCs were detected during long term follow up.

Adolescent↗
PubMed2004

Treatment of chronic hepatitis c.

Since the discovering of the hepatitis C virus in 1989, the treatment of hepatitis C has considerably improved. Initially, with interferon alpha used as a single drug, the sustained virological response rate was below 20%. Then, with the use of combination therapy of interferon a with ribavirin, the response rate increased to 41%. More recently, combination of pegylated interferons with ribavirin give a response rate of about 54-63%. The long-term follow-up studies showed that sustained virological response is generally associated with clinical and histological improvement. The indication of therapy is mainly based on the results of the liver biopsy which is the best way to assess the prognosis of the liver disease. Therefore, treatment is indicated in patients with moderate or severe necroinflammation or fibrosis. The tolerability of combination therapy is relatively poor with a frequent flu-like syndrome and an impaired quality of life. Factors associated with a poor response to treatment are essentially genotype 1 and high viral load. To further improve the efficacy of therapy, different new drugs are under investigation (amantadine, cytokines). These drugs may be candidates for new combinations. In addition, intensive research is currently done for the development of inhibitors of viral enzymes (helicase, protease or polymerase) and anti-sense oligonucleotides, ribozymes and therapeutic vaccine.

Hepatitis C, Chronic↗
PubMed2003

Liver fibrosis is not associated with steatosis but with necroinflammation in French patients with chronic hepatitis C.

BACKGROUND: In chronic hepatitis C, it has been suggested that steatosis could accelerate progression of fibrosis. However, results of the few published studies are controversial. AIM: To determine the characteristics (epidemiological, biological, and histological) associated with steatosis and its relationship with liver lesions (grade of necroinflammation and stage of fibrosis) in patients with chronic hepatitis C. METHODS: From November 2000 to July 2001, untreated consecutive adults with chronic hepatitis C admitted for liver biopsy were included in this study. On the day of liver biopsy, a questionnaire for risk factors was completed prospectively, and a blood sample was obtained for laboratory analysis. RESULTS: Our study included 290 patients (143 men, 147 women). Mean body mass index (BMI) was 24 (3.8) kg/m(2). Proportions of patients with genotypes 1 and 3 were, respectively, 48% and 18%. A total of 135 patients (46.6%) had steatosis. Liver steatosis, in multivariate analysis, was associated with hepatitis C virus genotype 3, higher grade of necroinflammation, and higher BMI. There was no significant association between stage of fibrosis and liver steatosis. In multivariate analysis, high stage of fibrosis was associated with male sex, age over 50 years, high BMI, and high grade of necroinflammation. CONCLUSION: In our population of patients with chronic hepatitis C, steatosis does not seem to be an important determinant of liver fibrosis. High grade of necroinflammation is associated with a high stage of fibrosis.

Adult↗
PubMed2003

Second infection with a different hepatitis C virus genotype in a intravenous drug user during interferon therapy.

The prevalence of antibodies against hepatitis C virus (anti-HCV) among intravenous drug users (IVDU) has consistently been very high. Cross challenge studies in chimpanzees provide evidence that reinfection with different HCV strains may occur. In humans, reinfection with different HCV strains has been reported in multitransfused haemophiliacs and recently in IVDU but no case has been reported while on interferon (IFN) therapy. We report on a 22 year old woman who was treated with IFN alpha for HCV genotype 3a chronic infection. At six months, HCV RNA was undetectable by reverse transcription-polymerase chain reaction. In October 1997, while still on IFN, she developed an acute hepatitis after an intravenous drug injection and HCV genotype 1a infection was identified using genotyping and sequencing methods. IFN therapy was continued until August 1998, and in January 1999 HCV-RNA was not detectable. Our case indicates that the previous HCV infection might have prevented development of chronicity. An alternative explanation is that IFN, while not preventing acute hepatitis C, may prevent chronicity. The risk of multiple infection in IVDU underlines the need for preventive strategies.

Acute Disease↗
PubMed2002

Hypervariable region 1 quasispecies in hepatitis C virus genotypes 1b and 3 infected patients with normal and abnormal alanine aminotransferase levels.

The role of hepatitis C virus (HCV) heterogeneity in the severity of chronic hepatitis C infection remains unclear. Our aim was to study the hypervariable region 1 (HVR1) heterogeneity in patients with chronic hepatitis C infected with genotype 1b or 3 and with normal or abnormal alanine aminotransferase (ALT). HVR1 quasispecies were assessed by single strand conformational polymorphism (SSCP) in 67 patients with chronic hepatitis C, including 35 with persistently normal ALT and 32 with abnormal ALT. Sixty-two patients underwent a liver biopsy. Among the 67 patients, 40 were infected with genotype 1b and 27 with genotype 3. In univariate analysis, low heterogeneity (<or= 3 bands at SSCP) was significantly associated with normal ALT (P < 0.001), milder histological lesions (activity, P=0.02; fibrosis, P=0.04), and at the limit of significance for genotype 1b (P=0.07). In multivariate analysis, low heterogeneity was significantly and independently associated with normal ALT (P=0.09) and genotype 1b (P=0.03). In patients with chronic hepatitis C, a low viral heterogeneity is significantly and independently associated with normal ALT and genotype 1b. These results are consistent with the view that patients with normal ALT have a different immune response against HCV resulting in a low HCV heterogeneity.

Adult↗
PubMed2001

Cytokines as predictors for sustained response and as markers for immunomodulation in patients with chronic hepatitis C.

OBJECTIVES: (i) To characterize serum cytokine levels of tumor necrosis factor alpha (TNF alpha), interleukin 6 (IL 6), IL 8 and IL 12 in non-cirrhotic patients with chronic hepatitis C, (ii) to correlate the levels of these cytokines with the degree of the disease at the basal level, (iii) to correlate these levels with the response to therapy, (iv) to compare profiles of cytokines in monotherapy (MT) versus combination therapy (CT), and (v) to compare the immunomodulatory effects of MT versus CT. DESIGN AND METHODS: 47 patients were enrolled in the study. The controls were 120 volunteers (recruited from students and staff) that did not present HCV RNA positive and were not known to suffer any other metabolic disease. Thirty patients formed the other group of controls, with alcoholic liver disease (ALD). Serum cytokine levels were assessed using enzyme-linked immunosorbent assay (ELISA). RESULTS: The sustained responders (SRs) have basal values much lower than relapsed responders (RRs) and non-responders (NRs) regardless of the therapy. CONCLUSIONS: Cytokines can be used as non-invasive markers for sustained response and as monitors for the outcome of therapy.

Adult↗
PubMed2001

Hepatitis after intravenous buprenorphine misuse in heroin addicts.

BACKGROUND: Sublingual buprenorphine is used as a substitution drug in heroin addicts. Although buprenorphine inhibits mitochondrial function at high concentrations in experimental animals, these effects should not occur after therapeutic sublingual doses, which give very low plasma concentrations. CASE REPORTS: We report four cases of former heroin addicts infected with hepatitis C virus and placed on substitution therapy with buprenorphine. These patients exhibited a marked increase in serum alanine amino transferase (30-, 37-, 13- and 50-times the upper limit of normal, respectively) after injecting buprenorphine intravenously and three of them also became jaundiced. Interruption of buprenorphine injections was associated with prompt recovery, even though two of these patients continued buprenorphine by the sublingual route. A fifth patient carrying the hepatitis C and human immunodeficiency viruses, developed jaundice and asterixis with panlobular liver necrosis and microvesicular steatosis after using sublingual buprenorphine and small doses of paracetamol and aspirin. CONCLUSIONS: Although buprenorphine hepatitis is most uncommon even after intravenous misuse, addicts placed on buprenorphine substitution should be repeatedly warned not to use it intravenously. Higher drug concentrations could trigger hepatitis in a few intravenous users, possibly those whose mitochondrial function is already impaired by viral infections and other factors.

Administration, Sublingual↗
PubMed2001

Quantitation of hepatic hepatitis C virus RNA in patients with chronic hepatitis C. Relationship with severity of disease, viral genotype and response to treatment.

BACKGROUND/AIMS: To determine the correlation between hepatic hepatitis C virus (HCV) RNA and histological lesions, viral genotype or response to alpha interferon therapy. METHODS: Forty-three patients with chronic hepatitis C (14 sustained responders (SR) and 29 non-sustained responders (NSR)) were studied. A liver tissue sample was obtained before and 1 year after treatment. Quantitation of hepatic HCV-RNA was performed by competitive PCR. RESULTS: Before treatment, HCV-RNA was detectable in all liver samples. There was no association between hepatic HCV-RNA and the severity of liver lesions. There was a significant association between old age and hepatic HCV-RNA (P = 0.03). There was an association, at the limit of significance, between genotype 1 and high hepatic HCV-RNA amounts (15 x 106 and 4.1 x 10(6) copies/g, P = 0.05). Pre-treatment hepatic HCV-RNA amounts were lower in SRs than in others (0.65 x 10(6) and 13.2 x 10(6) copies/g, P = 0.0002). After treatment, no liver HCV-RNA was detectable in the SRs while in the NSRs, the HCV-RNA amounts were unchanged. CONCLUSIONS: The amount of hepatic HCV-RNA is correlated to genotype and response to interferon therapy but not to histologic lesions. Hepatic HCV-RNA clearance is observed in SRs, suggesting viral eradication.

Adult↗
PubMed2001

Prospective study on anti-hepatitis C virus-positive patients with persistently normal serum alanine transaminase with or without detectable serum hepatitis C virus RNA.

A significant proportion of patients with detectable antibodies to hepatitis C virus have normal serum alanine transaminase levels. Our aim was to study the outcome of this group. Between 1992 and 1999, 135 consecutive anti-HCV-positive patients with persistently normal ALT were followed for 3.6 +/- 2.3 years (0.5 to 8.5 years), 108 had a liver biopsy at inclusion, and 24 had a second liver biopsy 3.5 +/- 1.0 years later. Serum HCV RNA was detectable with PCR in 94 patients (69%) and not detectable in 41 patients (31%). Patients with and without detectable serum HCV RNA had similar epidemiological characteristics. Serum ALT levels and anti-HCV ratio were lower (P =.001), and histological lesions had lower grade and stage in patients without detectable serum HCV RNA (P =.001). Liver HCV RNA was not detectable with PCR in the 12-serum HCV RNA-negative patients tested. During follow-up, all patients without detectable serum HCV RNA remained HCV RNA-negative and kept normal serum ALT; all patients with detectable serum HCV RNA remained HCV RNA-positive, 20 (21%) had a slight fluctuation of serum ALT above the upper limit of normal. No significant changes were observed in the liver lesions of the 24 patients who underwent a second liver biopsy. In anti-HCV-positive patients with persistently normal serum ALT, histological lesions are significantly lower in HCV RNA-negative than in HCV RNA-positive patients. During follow-up, the HCV RNA status of patients remained unchanged; 21% of the patients with detectable serum HCV RNA had slight increase in serum ALT levels, but histological lesions remained stable.

Adult↗
PubMed2001

The influence of human immunodeficiency virus coinfection on chronic hepatitis C in injection drug users: a long-term retrospective cohort study.

In this study we analyzed the influence of human immunodeficiency virus (HIV) infection on the course of chronic hepatitis C through multivariate analysis including age, alcohol consumption, immune status, and hepatitis C virus (HCV)-related virologic factors. Eighty HIV-positive and 80 HIV-negative injection drug users included between 1980 and 1995 were matched according to age, gender, and duration of HCV infection and followed-up during 52 months. The progression to cirrhosis was the primary outcome measure. The impact of HIV on HCV-RNA load, histologic activity index, response to interferon therapy, and liver-related death was also considered. In HIV-positive patients, chronic hepatitis C was characterized by higher serum HCV-RNA levels (P =.012), higher total Knodell score (P =.011), and poorer sustained response to interferon therapy (P =.009). High serum HCV-RNA level was associated with low CD4-lymphocyte count (P =.001). Necroinflamatory score was higher in HIV-positive patients (P =.023) independently of the CD4-lymphocyte count, whereas increased fibrosis was related to decreased CD4-lymphocyte count (P =.011). The progression to cirrhosis was accelerated in HIV-positive patients with low CD4 cell count (RR = 4.06, P =.024) and in interferon-untreated patients (RR = 4.76, P =.001), independently of age at HCV infection (P =.001). Cirrhosis caused death in 5 HIV-positive patients. The risk of death related to cirrhosis was increased in heavy drinkers (RR = 10.8, P =.001) and in HIV-positive patients with CD4 cell count less than 200/mm(3) (RR = 11.9, P =.007). In this retrospective cohort study, HIV coinfection worsened the outcome of chronic hepatitis C, increasing both serum HCV-RNA level and liver damage and decreasing sustained response to interferon therapy. Age and alcohol were cofactors associated with cirrhosis and mortality. Interferon therapy had a protective effect against HCV-related cirrhosis no matter what the patient's HIV status was.

Adult↗
PubMed2001

Tolerability of treatments for viral hepatitis.

Interferon-alpha is the most widely used antiviral drug in chronic hepatitis B and C. Tolerability is usually good and serious adverse effects are rare. Most of the adverse effects are mild or transient and do not necessitate drug withdrawal. More than 90% of patients who are given interferon-alpha achieve 6 months to 1 year of treatment without serious adverse effects. The serious adverse effects usually occur in predisposed patients with pre-existing organ dysfunction. Nevertheless, careful selection of patients for therapy and observation during therapy are recommended. Nucleoside analogues are promising drugs in the treatment of chronic hepatitis B through inhibition of viral DNA polymerase. Lamivudine has been licensed for use in this indication. Its tolerability is excellent even when used for periods of 1 year or more. The main concern is the relatively high incidence of viral resistance resulting in breakthrough during or relapse after therapy. In the treatment of chronic hepatitis C, ribavirin, in combination with interferon-alpha is currently the reference therapy. The main adverse effect is haemolytic anaemia, which necessitates careful monitoring and adjustment of dosage in many cases. Recently, large trials showed the better efficacy of pegylated interferons as compared with standard interferon. The combination of pegylated interferon with ribavirin is under evaluation.

Antiviral Agents↗