A prospective study of the evolution of lamivudine resistance mutations in patients with chronic hepatitis B treated with lamivudine.

Lamivudine resistance has been described in subjects with chronic hepatitis B infections, associated with mutations in the viral polymerase gene. The objective of this study was to estimate the emergence rate of lamivudine-resistant viral strains and their consequences over a 2-year period. We evaluated 283 lamivudine-naïve subjects with chronic hepatitis B. Clinical and virological features were assessed at inclusion and every 6 months thereafter. Viral DNA was characterized using polymerase chain reaction (PCR)-based sequencing. Potential risk factors for the emergence of lamivudine resistance mutations were assessed using logistic regression analysis. The annualized incidence rate for viral polymerase mutations was 22%. The only independent risk factor identified was high viral load, at inclusion. Detectable viral DNA and elevated transaminases were more frequent in subjects harbouring mutant viral strains, and these underwent a lower rate of hepatitis B e seroconversion. All subjects responded favourably to treatment, with no difference in symptoms between the two groups. This prospective cohort study identified lamivudine-resistant mutations emerging in 22% of subjects, yearly, which were apparently not associated with clinical aggravation over the study period.

Long term histological improvement and clearance of intrahepatic hepatitis C virus RNA following sustained response to interferon-ribavirin combination therapy in liver transplanted patients with hepatitis C virus recurrence.

BACKGROUND AND AIMS: A proportion of liver transplanted patients with recurrent chronic hepatitis have a sustained virological response to combination therapy with interferon plus ribavirin. However, the long term benefit of antiviral therapy with regard to hepatitis C virus (HCV) RNA clearance remains unknown in patients with HCV recurrence. This study examined the long term biochemical, virological, and histological outcome in transplanted patients with recurrent chronic hepatitis who had a sustained virological response to antiviral therapy. PATIENTS AND METHODS: Fifty four patients with recurrent hepatitis C were treated with antiviral therapy involving induction by combination therapy (interferon (IFN) plus ribavirin) for six months and maintenance ribavirin therapy for 12 months. Fourteen patients who had recurrent chronic hepatitis and sustained virological response to antiviral therapy were followed for three years after the end of antiviral therapy. Serum alanine aminotransferases were assessed every three months during the observation period. Serum hepatitis C RNA detected by polymerase chain reaction was evaluated every six months during follow up, and protocol biopsy procedures were performed routinely every year. Semiquantitative histopathological assessment of allograft hepatitis was performed using the Knodell score and HCV was also detected by polymerase chain reaction on frozen graft tissue samples. RESULTS: At the end of antiviral therapy, the sustained response rate was 26%. A complete response (normal serum alanine aminotransferase level and undetectable serum HCV RNA) was achieved in 13/14 (93%) patients three years after the end of treatment. A comparison of liver histology findings before and after a mean of three years after antiviral therapy showed a clear improvement in 12/14 (86%) patients. In 5/14 (36%) patients, the last biopsy showed normal or near normal histological findings. After three years of follow up, the total Knodell score was 3.2 (range 1-8) versus 8.3 (range 5-12) before treatment (p=0.001). Graft HCV RNA was detectable before treatment in all 14 patients and was undetectable at the end of follow up in 13/14 (93%) patients tested. CONCLUSION: In patients with biochemical and virological responses induced by ribavirin and interferon, a complete response was sustained in 93% for at least three years after cessation of therapy. This long term response was associated with absence of detectable intrahepatic hepatitis C RNA and marked histological improvement.

A rapid and easy PCR-RFLP method for genotyping Serratia marcescens strains isolated in different hospital outbreaks and patient environments in the Lyon area, France.

A new genotyping method for Serratia marcescens is described. This method uses the flagellin gene as target for polymerase chain reaction amplification and Alu I restriction fragment length polymorphism. The strains tested belonged to 13 different hospital clusters of S. marcescens isolated between 1983 and 1988, concerning outbreaks and/or patient environments in different hospital units in Lyon and the Rhone-Alpes region of France. Initially, the classification had been performed by marcescinotyping. These strains were then tested by ribotyping and genotyping of the flagellin gene. Genotyping showed similar classification to ribotyping. The genotyping method is the easiest technique, as reproducible as ribotyping, and with almost the same ability to discriminate different strains. It does not need expensive equipment, is more rapid, and is less labor intensive than ribotyping. With this method, all strains of S. marcescens including sporadic isolates could be amplified and typed. Antibiotic sensitivity determination was found to be a useful complementary and confirmation test for all these typing methods.

Fibroblast growth factor receptor 1 (FGFR1) is over-expressed in benign prostatic hyperplasia whereas FGFR2-IIIc and FGFR3 are not.

OBJECTIVE: Benign prostatic hyperplasia (BPH) is one of the major public health problems among men: 50% of men over 55 are concerned with this disease. Prostate growth is under the control of androgens which act by means of several growth factors such as fibroblast growth factors (FGFs), epidermal growth factor and transforming growth factor beta. Basic FGF (bFGF) has been shown to stimulate prostatic stromal growth. In BPH, bFGF concentration is two- to threefold higher than in normal prostate. In this work, the bFGF receptors (FGFR1, FGFR2-IIIc and FGFR3) genes expression was evaluated to study the correlation between the expression of bFGF receptors and induction of BPH. METHODS: The expression of FGFRs was analyzed by RT-PCR, FGFR1 was localized by immunohistochemistry and protein expression was evaluated by Western blot. RESULTS: A two- to eightfold over-expression of FGFR1 was observed in BPH compared with normal prostates. FGFR1 was localized in the stroma both in BPH and in normal prostates and 1.5- to 2.5-fold over-expression of the protein was observed. The expression of FGFR2-IIIc and FGFR3, more secondary receptors, was not significantly different between BPH and normal prostates. CONCLUSIONS: bFGF receptors and particularly FGFR1 seem to be involved in the induction and evolution of BPH and probably potentiate bFGF over-expression effects in BPH.

Thiram-induced cytotoxicity is accompanied by a rapid and drastic oxidation of reduced glutathione with consecutive lipid peroxidation and cell death.

The toxic effect of thiram, a widely used dithiocarbamate fungicide, was investigated in cultured human skin fibroblasts. Cell survival assays demonstrated that thiram induced a dose-dependent decrease in the viable cell recovery. Thiram exposure resulted in a rapid depletion of intracellular reduced glutathione (GSH) content with a concomitant increase in oxidized glutathione (GSSG) concentration. Alteration of glutathione levels was accompanied by a dose-dependent decrease in the activity of glutathione reductase (GR), a key enzyme for the regeneration of GSH from GSSG. Thiram-exposed cells exhibited increased lipid peroxidation reflected by enhanced thiobarbituric acid reactive substances (TBARS) production, suggesting that GSH depletion and the lower GR activity gave rise to increased oxidative processes. To investigate the role of decreased GSH content in the toxicity of thiram, GSH levels were modulated prior to exposure. Pretreatment of fibroblasts with N-acetyl-L-cysteine (NAC), a GSH biosynthesis precursor, prevented both lipid peroxidation and cell death induced by thiram exposure. In contrast, thiram cytotoxicity was exacerbated by the previous depletion of cellular GSH by L-buthionine-(S,R)-sulfoximine (BSO). Taken together, these results strongly suggest that thiram induces GSH depletion, leading to oxidative stress and finally cell death.

An evaluation of thiram toxicity on cultured human skin fibroblasts.

Thiram is widely used in agriculture as a fungicide and, to a lesser extent, as a vulcanizing agent in the rubber industry. In spite of the extensive use of thiram, knowledge on its toxicity and health risk remains limited, and few investigations have been performed to assess specific damage at the cellular and subcellular level. We report here the cytotoxic effects of thiram on cultured human skin fibroblasts. Our results demonstrated that thiram exposure induced a dose- and time-dependent decrease in the viable cell recovery with 100% cell death observed with a concentration of 5.0 mg/l. As judged by morphological changes and biochemical criteria, thiram-mediated cell death was not of the apoptotic but seemed to be of the necrotic type. This cell death was not associated with a modification of gene expression of different constituents of the extracellular matrix. A late increase of lactate production was evident after thiram treatment, suggesting a mitochondrial metabolic pathway dysfunction as reported by other authors using similar compounds. However, this phenomenon appeared as a secondary response to the toxic action of thiram. The cytotoxic effect of thiram is possibly due to an oxidant effect inherent to the structure of thiram and the interaction between thiram and vital cellular molecules.

Quantitation of reduced and total glutathione at the femtomole level by high-performance liquid chromatography with fluorescence detection: application to red blood cells and cultured fibroblasts.

A new rapid and highly sensitive HPLC method with ortho-phthalaldehyde (OPA) pre-column derivatization has been developed for determination of reduced glutathione (GSH) and total glutathione (GSHt) in human red blood cells and cultured fibroblasts. OPA derivatives are separated on a reversed-phase HPLC column with an acetonitrile-sodium acetate gradient system and detected fluorimetrically. An internal standard (glutathione ethyl ester) is added to facilitate quantitation. Total glutathione is determined after reduction of disulfide groups with dithiothreitol; the oxidized glutathione (GSSG) concentration is calculated by subtraction of the GSH level from the GSHt level. The assay shows high sensitivity (50 fmol per injection, the lowest reported), good precision (C.V. <5.0%), an analytical recovery of GSH and GSSG close to 100%, and linearity (r > 0.999). This HPLC technique is very simple and rapid. Its wide applicability and high sensitivity make it a convenient and reliable method for glutathione determination in various biological samples.

The up-regulation of vascular endothelial growth factor in mutated Ha-ras HaCaT cell lines is reduced by a farnesyl transferase inhibitor.

The induction of tumor angiogenesis is mediated in particular by an increased production of VEGF. As ras oncogene is implicated in tumorigenesis, the inhibition of farnesyl transferase activity has recently been developed. The purpose of this study was to evaluate whether expression of mutated Ha-ras oncogene is associated with an altered expression of VEGF in an in vitro model of human skin carcinogenesis and to appreciate the effect of a new farnesyl transferase inhibitor on this VEGF expression. The amounts of VEGF secreted by an HaCaT cell line and two cell clones (metastatic or not) obtained after mutated c-Ha-ras transfection were compared. Our findings showed that the release of VEGF is greater for HaCaT-ras than for HaCaT cells and could be down-regulated using a protein farnesyl transferase inhibitor, in a reversible and dose-dependent manner. These results confirm that the Ha-ras oncogene can contribute to tumor development and progression of epidermal tumors through neoangiogenesis and that farnesyl transferase inhibitors as anticancer drugs may be efficient for the reduction of skin tumor growth.

Variability of Ha-ras (codon 12) proto-oncogene mutations in diverse thyroid cancers.

Structural alterations to proto-oncogene sequences may be involved in the pathogenesis of human thyroid neoplasms. We studied 128 thyroid tumours (35 benign and 93 malignant) for ras gene point mutations in three different codons (12, 13 and 61) using a restriction fragment length polymorphism technique and direct sequencing of double-stranded DNA on polymerase chain-reaction-amplified tumour DNA. We found a high frequency of ras mutation for the Ha-ras codon 12 in follicular adenomas (7 of 35), particularly in atypical adenomas (5 of 17), in follicular carcinomas (6 of 19), with a high percentage for Hurthle cell carcinomas (6 of 11), and in papillary carcinomas (4 of 66). Point mutations for other ras genes in different codons studied were weak to absent. No mutation was found in undifferentiated carcinomas (n = 8). The predominant amino acid substitution both in the adenomas and in the differentiated tumours was glycine to valine (GGC to GTC) at position 12 of the Ha-ras gene. Our results obtained on a large series confirm the frequent occurrence of Ha-ras codon 12 gene mutations both in adenomas and in carcinomas. The frequency of ras mutations is linked to the geographical origin of the population studied and varies (0-85%) from one cancer type to another according to published data. Therefore, these mutations are merely an expression of cellular transformation.

Ha-ras oncogene (codon 12) mutation in thyroid carcinogenesis: analysis of 60 benign and malignant thyroid tumors.

Protooncogene Ha-ras codon 12 mutations are frequently observed in thyroid cancers. However, their role in the initiation and development of this pathology remains to be clarified. Here we present a preliminary study using 60 samples corresponding to different types of cancer. DNA amplification by PCR (polymerase chain reaction) followed by RFLP (restriction fragment length polymorphism) analysis enabled the detection of a point mutation in codon 12 of the Ha-ras oncogene in human thyroid adenomas and carcinomas. Our results confirm the high frequency of codon 12 Ha-ras oncogene mutation in thyroid tumors: adenomas 33%, with a particularly high rate for atypical adenomas 71%, follicular carcinomas 33%, and papillary carcinomas 19% (n = 18, 7, 12, 26, respectively). No mutation was detected in undifferentiated carcinomas (n = 4). The Ha-ras codon 12 gene point mutation can exist at all stages of development of both benign and malignant thyroid tumors. It may be a necessary part of the thyroid tumorigenesis process, but it is not the only carcinogenic factor. Additionally, the association with other molecular anomalies should be sought depending on the thyroid cancer type.

[HBV-DNA assay by hybridization in solution. Value of low levels measured with the Abbott-Genostics device]. / Dosage de l'ADN du VHB par hybridation en milieu liquide. Valeur des taux faibles mesurés avec la trousse Abbott-Genostics.

Quantitation of HBV-DNA is the most precise test for measuring viral replication. A commercial liquid phase hybridation test (Abbott) is now commonly used for diagnosis and monitoring of chronic hepatitis B. Interpretation of weak positive results obtained with this test are often difficult. Fifty-four sera with a concentration lower than 12 pg/ml with the Abbott HBV-DNA assay were tested with another commercial hybridation assay (Digene-Murex) and with an in-house PCR test. PCR is positive in 24 sera among the 35 HBs antigen positive sera, but is always negative in HBs Antigene negative sera. All the HBe Antigen positive sera were positive with the PCR test. A positive result was obtained with the Digene test in only 14 sera, 13 of them were confirmed by PCR. Ten sera among the remaining 11 PCR positive sera had a low HBV-DNA concentration but under the Digene cut-off level (10 pg/ml). The sensitivity could be greatly enforced with a lower cut-off level without any lack of specificity. The PCR test remains very helpful for sera with low concentration of HBV-DNA.

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.

Preparation of an anti-acid sphingomyelinase monoclonal antibody for the quantitative determination and polypeptide analysis of lysosomal sphingomyelinase in fibroblasts from normal and Niemann-Pick type A patients.

An anti-acid sphingomyelinase monoclonal antibody has been prepared using an in vitro booster technique. The antigen, acid sphingomyelinase, was purified from human placentas by sequential chromatographic steps in the presence of the non-ionic detergent Nonidet P40. This monoclonal antibody (MAB 236) precipitates specifically the enzyme activity by immunoadsorption techniques and presents the same specificity to normal and mutated sphingomyelinase in Niemann-Pick type A patients. MAB 236 is the first antibody able to precipitate the protein in the presence of detergent thereby permitting the quantitative determination of normal and mutated sphingomyelinase in tissue and cell extracts. Polypeptide analysis and quantitative determination experiments using this monoclonal antibody showed no difference between patients and normal controls.

Study of a monoclonal antibody specific to epithelial cells of mammalian thymuses.

Hybridomas between spleen cells from BALB/c mice and Sp2/O-Ag14 mycloma cell line are performed by PEG fusion. An in vitro booster is realized with human thymic reticulo-epithelial cell cultures as antigen. A monoclonal antibody (3H9) directed against the thymic epithelium and stratified epithelia of mammals has been obtained and characterized.

Production of monoclonal antibodies to dehydroepiandrosterone-sulphate after immunization of mouse with dehydroepiandrosterone-bovine serum albumin conjugate.

Monoclonal antibodies with a much higher specificity for DHA-S than for DHA were obtained from a BALB/c mouse immunized with a non-sulphated DHA-7CMO-BSA antigen. An improved fusion technique using PEG containing 10% DMSO instead of PEG alone increased the number of positive hybridomas. One of the five monoclonal antibodies obtained, showed a high affinity for DHA-S (Ka = 10(10) M-1) and very low cross-reactions with androsterone (0.62%) and androsterone sulphate (0.83%) which made it potentially useful for direct quantitation of DHA-S in human serum.

[Nosocomial septicemia and pseudobacteremia caused by Serratia marcescens]. / Septicémies nosocomiales et pseudo-bactériémies à Serratia marcescens.

An epidemiological survey was carried out which included a dual epidemic of septicaemia and pseudo-bacteremia caused by Serratia marcescens. The survey enabled 15 septicaemias and 43 pseudobacteremias to be detected in a regional hospital between March and August, 1983. Two mishandlings were at the origin of the outbreak: citrated tube normally reserved for coagulation tests were severely contaminated by Serratia marcescens, and inaccurate samplings had been made. Once the mechanisms of contamination were found, specific preventive measures put an end to the epidemic. The authors insist on the need for uncontaminated tubes and citrate solutions and for the development of precise sampling methods which are essential to avoid the occurrence of pseudo-bacteremia or septicaemia. It is important to detect such epidemics at an early stage by an efficient control of nosocomial infections, thus avoiding their extension.

Prevalence and significance of hepatitis B virus antigens: expression in peripheral blood mononuclear cells in chronic active hepatitis.

One-hundred four chronic active hepatitis (CAH) patients were investigated for the expression of the hepatitis B virus (HBV) surface and core gene products (HBs Ag, HBc/HBe Ags) in peripheral blood mononuclear cells (PBMC). Two-thirds of 59 HBs antigenemic patients expressed HBs Ag in PBMC but 26% of cases positive for both anti-HBs and anti-HBc also expressed HBs Ag while none of the controls reacted. Among HBs antigenemic patients, only those who replicated HBV express the core gene products (HBc and/or HBe Ag) in PBMC, and high replicators did so more often than low replicators (P less than 0.05). The HBs Ag prevalence in PBMC, although slightly higher among HBe Ag/DNAp-positive cases could not be correlated with the intensity of HBV replication. In 16 cases (8 replicants and 8 nonreplicants) HBV DNA was detected by DNA hybridization spot test, while 8 controls devoid of HBV markers were negative. Both T and non-T cells reacted similarly for antigenic or genomic HBV markers. When the expression of HBV gene products in PBMC among 43 cases with HBs antigenemia was compared with that in the liver, a good correlation was found in 70% of cases for HBs Ag but in only 40% for HBc and HBe Ags. By contrast, among 38 cases lacking HBs Ag in the serum but positive for anti-HBc with or without anti-HBs, concordance between liver and PBMC expression of core gene products (69%) was better than for HBs antigenemic patients (40%). These data suggest that PBMC including T lymphocytes may represent the second-best HBV target and may mimic the steps of HBV cycle within hepatocytes.

Combined tetanus-rabies vaccination.

Studies in mice have shown that Calcium Phosphate adsorbed tetanus toxoid (IPADT) can be used as a vehicle for freezedried rabies vaccine. Trials were undertaken in human volunteers and patients receiving a post-exposure treatment using the same vaccines to evaluate tolerance and antibody response to both vaccines.

Antigenic competition between two sequentially acting antigens. II.--The life-span and sensitivity to corticosteroids or to irradiation of T suppressor cells.

We have studied the immunosuppressive function of T cells using the antigenic competition system. A first antigen (inhibitory antigen) consisting of horse red blood cells is given as a primary or a secondary stimulus. This is followed 4 days later by a second antigen (test antigen) consisting of sheep red blood cells. Both antigens are given intraperitonealy. We have estimated the life-span of T suppressor cells by studying the time necessary for the abolition of antigenic competition after adult thymectomy. We find the response disappears after 6 weeks. The cortico- and radio-sensitivity of T suppressor cells were studied by the effect of hydrocortisone or of irradiation on antigenic competition. Lymphocytes from treated mice were transferred to compatible Nude mice whose ability to show antigenic competition was then studied. By these tichniques we have shown that T suppressor cells are not destroyed by hydrocortisone but their immunosuppressive function is merely temporarily inhibited during the time of high level of this hormone. Furthermore hydrocortisone only inhibits the T suppressor cells when the inhibitory antigen is given as a primary stimulus and shortly after the administration of the steroid. Irradiation on the other hand destroys or inactivates one out two or both cells with a suppressive activity (T suppressor cell and macrophage).