Search PubMed⌕ Search

Biomedical subjects

C Trepo

Publications and source records attributed to C Trepo.

At least 127 records · Page 7Linked to original sources
PubMed1995

A comparative evaluation of the sensitivity of seven anti-hepatitis C virus screening tests.

The sensitivity of the most recent generation of anti-hepatitis C virus (anti-HCV) screening tests from seven manufacturers was evaluated with a common panel of 530 specimens from 320 HCV-infected subjects. This panel included 221 samples from 57 seroconverters (53 pre-sero conversion negative specimens and 168 positive samples) and 309 selected specimens from 263 other HCV-infected patients of which 19% exhibited NS3 or core reactivity alone with the presence of HCV-RNA assessed by PCR. None of the seven screening tests detected all infectious and antibody-positive specimens. However, important differences were observed between these assays in the number of false-negative results, which seemed mainly due to nonreactivity of antibody to the NS3 antigen.

Antigen-Antibody Reactions↗
PubMed1995

The French experience of treatment of chronic type D hepatitis with a 12-month course of interferon alpha-2B. Results of a randomized controlled trial.

Hepatitis due to hepatitis delta virus (HDV) infection is generally associated with severe histological abnormalities and rapid progression of the disease. To assess the efficacy of recombinant interferon-a2b in treatment of chronic delta hepatitis, 22 patients were entered into a randomized controlled trial: 11 received interferon-a2b subcutaneously three times weekly for 12 months (5 MU/m2 for 4 months and then 3 MU/m2 for a further 8 months) and 11 were untreated. All patients were followed up for 6 months after the completion of therapy. Nine treated patients completed the trial: one was withdrawn with hyperthyroidism and one committed suicide. Serum ALT levels were normalized or significantly reduced, always within 3 months of initiating treatment, and remained so in 73% of treated patients at the 4th month and in 54.5% at the 12th month, compared with 18% and 18%, respectively, in the untreated group. Moreover, in seven of nine treated patients, interferon was associated with the clearance of serum HDV-RNA, associated with amelioration of the histological picture, whereas this occurred in only four of 11 untreated patients. On cessation of therapy, all patients but one experienced a biological and/or virological relapse over the 6-month follow up. In conclusion, our data confirm that HDV is sensitive to inhibition by interferon-a2b, although the schedule used did not achieve permanent control of the disease. The adverse effects of interferon require consideration; in particular, care will be needed to avoid serious psychiatric side effects.

Adult↗
PubMed1995

Hepatitis B, C, and D virus infections in patients with chronic hepatitis, cirrhosis, and hepatocellular carcinoma: a comparative study in Niger.

Eighty-nine Sahelian African patients with chronic active hepatitis (CAH) (14), cirrhosis (49), hepatocellular carcinoma (HCC) (26), and 47 controls were tested for hepatitis B virus (HBV, hepatitis B surface antigen [HBsAg]) and hepatitis D virus (HDV, anti-HDV antibody). Seventy-three percent of the patients were positive for HBsAg versus 29.8% of the controls (P < 0.0001). With anti-HDV test, 55.0% of the patients were positive versus 17.0% of the controls (P < 0.0001). To assess the prevalence of antibody to hepatitis C virus (HCV), we used an enzyme-linked immunosorbent assay for screening (anti-HCV2): 19.1% of the patients were positive versus 6.4% of the controls (P < 0.05). An association between HBsAg and anti-HDV-positive test results was found in 46.1% of the patients versus 6.4% of the controls (P < 0.0001). A combination of HBsAg and anti-HCV2-positive test results was found in 13.5% of the patients versus 2.2% of the controls (P < 0.05). Anti-HDV and anti-HCV2 test results were positive in 13.5% of the patients versus 2.2% of the controls (P < 0.05). Triple-positive test results (HBsAg, anti-HDV, and anti-HCV2) were found in 11.2% of the patients but in none of the controls (P < 0.025). Triple-negative test results were found in 14.6% of the patients versus 57.4% of the controls (P < 0.0001). The predominant association of the chronic HBV infection with CAH, cirrhosis, and HCC is confirmed in Sahelian Africa. The HDV superinfection (chronic HBV plus HDV infections) may be a major etiology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Spectrum of liver disease and duck hepatitis B virus infection in a large series of Chinese ducks with hepatocellular carcinoma.

The striking difference in the geographical distribution of liver cancer in ducks raised the question of whether duck hepatitis B virus (DHBV), like mammalian hepadnaviruses, could be an oncogenic agent. Hepatocellular carcinomas (HCCs) have been found only in domestic ducks in Qidong, China, where hepatitis B virus infection and aflatoxin B1 (AFB1) are both risk factors and where a high frequency of human HCCs has been reported. To date, the study of liver pathology occurring in Chinese ducks has been hampered by the small number of samples available. We describe here a series of 59 Chinese brown duck livers that were collected in Qidong more than 20 years ago and formalin fixed. Thirty-six HCCs, which ranged from well-differentiated trabecular to highly anaplastic type, were identified in relatively young ducks (average age, 3.3 years). Several unique features not previously reported, such as tumor giant cells, tumor necrosis, tumor thrombi in blood vessels, and inactive cirrhosis, were observed. Bile ductule proliferation, known to be a prominent feature of AFB1 exposure in ducks, was present in 86% of livers. Using polymerase chain reaction (PCR) and two primer pairs, located within conserved portions of the DHBV S and C genes, we demonstrated the presence of DHBV DNA in 23 of 34 HCCs analyzed (68%). The spectrum of liver pathology that we report in brown ducks from Qidong was never observed in Pekin ducks of the same age chronically infected with DHBV and followed under controlled conditions outside China, suggesting that causative factors other than virus infection may be involved in duck liver carcinogenesis observed in this area.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Treatment of hepatitis C].

The treatment of hepatitis C virus (HCV) infections is essentially known for chronic hepatitis C and is mainly restricted to interferon alpha. Initial trials have indicated that around 50% of the patients with chronic hepatitis C respond to alpha interferon (administered at 3 MU, thrice weekly, during 6 months) by normalizing alanine aminotransferase at the end of therapy, although 25% were found to relapse after therapy. Normalization of biochemical tests is associated with an improvement in liver histological features and with decrease or loss of HCV from serum and liver. Response to therapy is influenced by both duration and dose levels of the treatment. Following studies which showed that higher doses and longer duration were more effective than the current recommendations of 3MU thrice weekly for 6 months have recently conducted to the recent recommendation of a 12 month course of therapy using 3 MU. The outcome of therapy was also shown to be negatively influenced by longer duration of disease and presence of cirrhosis. More recently, the critical role of virological markers has been emphasized with a lower rate of response in patients infected with the genotype 1 b and a high viral load. However, these factors do not certainly predict for an individual patient the quality of the response. Therapeutical goals are: to precisely define pre-treatment scores of response able to give each individual patient the optimal treatment regimen, non responders to interferon alpha and patients with a transient benefit of therapy. Thus, development of new treatments appears critical among which those with other interferons and above all the bitherapy using ribavirin and interferon alpha which may have a marked increase in efficacy in comparison with interferon alpha used as monotherapy.

Antiviral Agents↗
PubMed1994

Mutagenesis of ras proto-oncogenes in rat liver tumors induced by vinyl chloride.

Vinyl chloride is a DNA-damaging carcinogen which induces liver angiosarcomas in humans and animals. Activation of the Ki-ras 2 gene by a GC-->AT transition at the second base of codon 13 in human liver angiosarcomas associated with occupational exposure to vinyl chloride has been reported recently. In order to compare the molecular pathways of carcinogenesis in humans and animals, Sprague-Dawley rats were exposed to vinyl chloride and hepatic tumors, including two hepatocellular carcinomas and five liver angiosarcomas, were investigated for mutations at codons 12, 13 and 61 of the Ha-ras, Ki-ras and N-ras genes. High molecular weight DNA was amplified by the polymerase chain reaction and point mutations were analyzed by allele specific oligonucleotide hybridization, direct sequencing of polymerase chain reaction products and sequencing after cloning. None of the tumors exhibited a mutation in codons 12, 13 and 61 of the Ki-ras gene, nor in codons 12 of the Ha-ras gene or 61 of the N-ras gene. However, an activating AT-->TA transversion at base 2 of codon 61 of the Ha-ras gene was detected in the two hepatocellular carcinomas. Mutations involving codon 13 (GGC-->GAC) and codon 36 (ATA-->CTA) of the N-ras A gene were detected in two liver angiosarcomas, suggesting that the nature of the ras gene affected by a given carcinogen depends on host factors specific to cell types. Several additional base pair substitutions were found in exon 1 of the N-ras B and C sequences. NIH 3T3 transfection assays and Southern blot analysis of DNA from transformed NIH 3T3 cells confirmed the presence of a dominant activated N-ras gene. These results emphasize the differences in the molecular pathways leading to tumors in humans and rats and within a given species between different cell types.

3T3 Cells↗
PubMed1994

Human hepatocellular carcinoma transplanted in nude mice: a relevant experimental model to assess tumoral destruction by alcoholization.

Intratumor ethanol injection was studied in the treatment of small hepatocellular carcinoma (HCC). One of the major drawbacks of this technique remains the lack of objective information about its efficiency and the practical conditions of injection. To ensure accurate evaluation of alcoholization, we developed a model based on the tumor obtained after subcutaneous injection of human hepatoma cell lines into nude mice. Each of three cell lines (Hep G2, Hep 3B, PLC/PRF/5) was tested on 24 mice. A total of 0.1 ml of a solution containing 5 x 10(6) cells was injected under the abdominal skin of a male nude mouse weighing 30 g. The Hep G2 cell line appeared to be the most suitable for the model. It enabled us to obtain tumors of 20 mm in diameter within a mean delay (m +/- SD) of 45 +/- 16 days (range: 29-60) with only a 25% failure rate. No visceral spreading of the carcinoma was noticed and the tumors obtained, similar to human HCC, were convenient to be measured, monitored, and treated by alcoholization. To validate this model for alcoholization, 38 tumors ranging in diameter from 10 to 20 mm were treated using either a unique centrotumoral injection (n = 27) or five cross-shaped injections (n = 11). Intratumor absolute ethanol injection resulted in tumoral necrosis which was easily quantified as a percentage of the tumor volume, using a semiquantitative method. It is concluded that the Hep G2 cell line transplanted in nude mice resulted in a relevant model to assess tumoral destruction by alcoholization.

Animals↗
PubMed1994

Identification of major antigenic domains of duck hepatitis B virus pre-S protein by peptide scanning.

Neutralization epitopes of duck hepatitis B virus (DHBV) have been previously mapped within the N-terminal portion of the pre-S protein using monoclonal antibodies. However, the immune response of ducks to this region is not well characterized at the amino acid level. To this end, we have immunized adult Pekin ducks with either DHBV positive serum or bacterially expressed DHBpre-S polypeptide representing the N-terminal portion of the DHBV pre-S region. We have demonstrated that adult ducks inoculated with either antigen developed antibodies to the DHBV pre-S region starting 5 to 10 days postinjection. The sera of all ducks, irrespective of the immunogen used, exhibited a significant protective activity against DHBV, as assessed in vivo. To identify which pre-S domains bind antibodies from these duck sera, we have used the Pepscan methodology with overlapping octapeptides spanning the DHBV pre-S sequence from amino acids 1 to 145. Using this approach, five major antigenic domains, 7KSMDVRRI14, 22NQLAGRMIP30, 58TLQNQGAW65, 71RRVGLSNPT79, and 127GDDPLLGNQ135 were identified within the DHBV pre-S region.

Amino Acid Sequence↗
PubMed1994

Hepatitis C: description of a highly sensitive method for clinical detection of viral RNA.

To improve the sensitivity of hepatitis C virus RNA (HCV RNA) detection in serum by 'nested' polymerase chain reaction (PCR), primers belonging to 5' non-coding (5'NC) regions were used to compare the classical phenol/chloroform technique by using the proteinase K and silica gel technique with guanidinium thiocyanate. The silica gel techniques was found to be more efficient and sensitive for the extraction and purification of viral RNA from serum samples. The silica gel technique also avoids contact with hazardous volatile chemicals like phenol and chloroform and provides a better protection for viral RNA. Furthermore, the RNA detection sensitivity was greatly improved by modifying the buffer for reverse transcription and PCR. Using silica gel extraction, and the modified buffer, viral RNA was detected in 699 sera from anti-HCV second generation ELISA positive patients. These sera were distributed in second generation RIBA confirmed, indeterminate and non confirmed groups with PCR positive rates of 71.4%, 45.7% and 15.8%, respectively. Two out of 227 ELISA negative patients showed the presence of HCV RNA in serum. An association between the presence of antibodies against a determined viral peptide and viremia was not detected.

Adult↗
PubMed1994

[Limits of immunoserologic and molecular diagnosis of hepatitis C].

Hepatitis C is the most common cause of post-transfusion hepatitis, as well as of the viral chronic liver disease in the western world. However since it is even more often asymptomatic than HBV, this is not truly recognized. The detection of hepatitis C can only rely on serological and virological methods and require their extensive use in screening programs. Following the molecular identification characterisation of HCV, it became possible to detect virus specific antibodies. The first generation Elisas were limited in their scope and have been replaced by second and third generation tests with better sensitivity and specificity. These assays detect antibodies to several sets of HCV protein including the C22 core, the C33 and C100, which correspond to the non structural regions (NS3 and NS4 respectively). More recently, NS5 proteins have also been added and synthetic peptides have replaced some of the recombinant proteins used initially. In spite of improved sensitivity and specificity, last generation Elisas still require confirmation by supplemental assays which can be of different types (immunoblot or combined Elisas) and include sets of structural and non structural recombinant proteins or peptides. New tests are needed to improve sensitivity and proficiency of this mandatory confirmation procedure. It is unclear at this stage whether the dogma inherited from HIV to request two sets of reactive antibodies will be also warranted by experience in HCV infection. The biggest limitation of present HCV tests is the delayed appearance of anti-HCV following primary infection. Even more worrisome is the fact that 10% of chronic infection with liver disease still remain seronegative, despite circulating HCV RNA in serum and/or liver as well as expressing HCV antigen demonstrable in liver tissue by immunostaining. Such a proportion is even more common in settings with immune deficiencies including organ transplantation and HIV infection. DNA amplification methods, such as PCR or others, must be used in order to demonstrate HCV RNA in combination with reverse transcription steps. This new powerful technology must be however applied under stringent quality control procedures and cannot be yet considered for screening or routine diagnosis although it can detect viremia as early as a week after exposure and help to monitor interferon treatment. During acute hepatitis, the delay in the appearance of anti-HCV hampers acute phase diagnosis. The early detection of HCV RNA in peripheral blood, confirms the diagnosis and opens up therapeutic possibilities. In chronic hepatitis, the diagnosis of seronegative forms may only be resolved by PCR. Moreover, the presence of HCV RNA in peripheral blood represents the only marker of on going viral replication and coincides with the severity of liver damage. During treatment with interferon, the follow up of HCV RNA sequences makes it possible to monitor its efficacy. The search for HCV RNA sequences directly in liver tissue shows that HCV may replicate in the liver in the absence of viremia. The presence of HCV RNA in the liver and the serum of liver transplanted patients is essential for the etiological diagnosis and management of hepatitis and bone marrow failure occurring after transplantation. Epidemiological study using PCR is a major tool in documenting vertical transmission between mother and child. Finally, PCR is important for the analysis of the HCV genome. Thus, in France there are at least three main strains, one close to the US prototype, the other close to the Japanese strain, possibly responsible for a more severe illness, and a third one distinct from the previous two. Two major HCV genotypes, F1 and F2, corresponding to HCV type I and II (USA prototype and Japanese) with prevalence of 45% and 55% respectively, were found in France. F1 infected patients were younger and more often male than F2 group. Nine of 28 patients in F1 genotype infected group had history of drug abuse but none i

Antibodies, Viral↗
PubMed1994

A randomized, controlled trial of interferon alfa-2b alone and with simultaneous prednisone for the treatment of chronic hepatitis B. French Multicenter Group.

The aim of the study was to evaluate the safety and effectiveness of interferon alpha-2b with or without concomitant corticosteroid treatment in patients with chronic hepatitis B. Fifty-six patients were randomly allocated to two treatment groups. Group I (n = 25) received interferon alpha-2b (INTRON A, Schering-Plough Corporation) 5 million unit subcutaneously, three times a week for 24 weeks. Group II (n = 31) received interferon according to the same protocol and prednisolone in decreasing doses of 60, 40, 20 mg for 6 weeks. The two groups were well matched for demographic, biochemical, virological and histologic features. Both groups were followed up for 24 weeks after treatment. No statistical difference was observed between the two groups at the end of the follow-up in alanine aminotransferase values, HBV DNA negativation, HBeAg loss, anti-HBe seroconversion and the Knodell score. The greater proportion of HBsAg clearance in the combination group, particularly in patients with low alanine aminotransferase values, was, however, not significant. In patients with low alanine aminotransferase values, only the Knodell score was significantly decreased in patients treated with interferon and prednisolone. The only factor which was found to be a predictor of response was the assumed duration of hepatitis. These findings showed that a concomitant short administration of corticosteroids during the first weeks of interferon therapy did not improve results with interferon alone.

Adult↗
PubMed1994

The treatment effect of alpha interferon in chronic hepatitis B is independent of pre-treatment variables. Results based on individual patient data from 10 clinical controlled trials. European Concerted Action on Viral Hepatitis (Eurohep).

Alpha interferon induces HBeAg seroconversion in about one third of treated patients and has become an established treatment of chronic hepatitis B. A number of smaller studies have suggested that response to treatment is more likely to occur in patients with higher levels of transaminases, with recent (adult) onset, a history of acute hepatitis, low levels of HBV DNA and in heterosexual males. The aim of this European co-operative study was to estimate the effect of alpha interferon more accurately and to evaluate the influence of host pre-treatment variables on the effect of interferon. Individual data were collected from 751 patients from 10 controlled clinical trials on alpha interferon (lymphoblastoid or recombinant) treatment for chronic hepatitis B. Alpha interferon was administered to 496 patients, while 255 were untreated controls. Individual patient data were analysed by survival analysis (log rank test and Cox regression analysis), stratified by trial, with the disappearance of HBeAg as the major endpoint. The results showed that the HBeAg disappearance rate with or without interferon treatment was higher in patients with high aminotransferase levels, with a history of acute hepatitis and in male heterosexual patients disregarding HIV status. If HIV-positive patients were excluded, the effect of sexual orientation was not significant. Therapy with alpha interferon increased the a priori HBeAg disappearance rate by a factor of 1.76; the relative treatment effect of alpha interferon was independent of the tested pretreatment host variables, but dependent on the total (intended) interferon dose (low dose < or = 200 MU/m2 increased HBeAg disappearance by a factor 1.37; medium/high dose > or = 200 MU/m2 increased HBeAg disappearance by a factor 2.05). In conclusion, this meta-analysis suggests that the effect of alpha interferon is less than previously assumed and independent of pretreatment host variables tested. It confirms the higher therapeutic benefit of a total dose exceeding 200 MU/m2 and of selection of patients based on disease activity and immune reactivity. Although all patient seem to have the same relative benefit, the absolute benefit of alpha interferon treatment seems to be greatest in patients with high transaminase levels and with a history of acute hepatitis.

Adult↗
PubMed1994

Duck hepatitis B virus infection, aflatoxin B1 and liver cancer in domestic Chinese ducks.

The oncogenicity of Duck hepatitis B virus (DHBV) is unclear since hepatocellular carcinomas (HCCs) have been reported only in domestic ducks in Qidong, an area of China where hepatitis B virus (HBV) and aflatoxin B1 (AFB1) are risk factors for liver cancer in man. In order to better define the association between DHBV infection, AFB1 and HCC we analysed a series of 16 duck liver samples collected from local farms in Qidong. HCC was found in eight and cirrhosis in one of these samples. Furthermore bile duct proliferation, characteristic of AFB1 exposure in ducks and other animal species, was found in these ducks. Integration of DHBV DNA into cellular DNA was observed in only one out of four DHBV positive HCCs, indicating that viral integration is not prerequisite for tumour development. In four remaining HCCs the polymerase chain reaction (PCR) failed to show any DHBV DNA suggesting that liver tumours do occur in polymerase chain reaction (PCR) failed to show any DHBV DNA suggesting that liver tumours do occur in these ducks in the absence of DHBV infection. In addition, AFB1-DNA adducts were detected by hplc-immunoassay in one such DHBV-negative tumour. In summary we demonstrate that risk factors other than DHBV, including AFB1 exposure, may be important in duck liver carcinogenesis in Qidong.

Aflatoxin B1↗