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Biomedical subjects

M Chevallier

Publications and source records attributed to M Chevallier.

At least 37 records · Page 2Linked to original sources
PubMed1999

Recurrence of hepatocellular carcinoma as a mixed hepatoblastoma after liver transplantation.

BACKGROUND: Hepatoblastoma is an exceptional cause of primary malignant liver tumour in the adult. PATIENT: The case is reported of an adult patient transplanted for alcoholic cirrhosis complicated by multifocal hepatocellular carcinoma in whom a recurrence in the form of a mixed hepatoblastoma invading the whole transplanted liver developed three months after liver transplantation. METHODS: Complete clinical, histopathological, and immunohistochemical data were reviewed. RESULTS: The recurrent tumour invaded the whole liver. The major component was a mixed hepatoblastoma, with an epithelial component expressing cytokeratin and a mesenchymal component expressing vimentin. The tumour also contained a minor hepatocarcinomatous component expressing alpha fetoprotein. The rapid growth of the tumour prevented any attempt at treatment. Although direct evidence is lacking, the most likely hypothesis to explain the observations is a marked phenotypic change in the initial malignant population at recurrence. CONCLUSION: This case supports a possible filiation between hepatocellular carcinoma and hepatoblastoma in adults.

Carcinoma, Hepatocellular↗
PubMed1998

Ribavirin monotherapy in patients with chronic hepatitis C: a retrospective study of 95 patients.

Ribavirin is a purine nucleoside that inhibits the replication of a variety of RNA viruses and was shown to have a transient efficacy in chronic hepatitis C during short-term therapy. We have analysed retrospectively its efficacy in 95 patients with liver biopsy-proven chronic hepatitis C. Patients received oral ribavirin (600-1200 mg daily) for a mean duration of 11 months. Alanine aminotransferase (ALT) levels returned to normal values in 38 patients (40%) and decreased by more than 50% in 20 other patients (21%). HCV RNA clearance from serum was observed in seven patients (8%). The biochemical response rate was higher in patients with chronic hepatitis (54%) than in those with cirrhosis (24%) (P = 0.003). Clearance of HCV RNA was observed in 10% of the patients with chronic hepatitis vs 4% of the patients with cirrhosis. In non-responders to interferon (IFN) therapy, ALT levels returned to normal values in 11 (26%) and HCV RNA became negative in one (2%), as compared to 48% and 3%, respectively, in those contraindicated for IFN. In 17 patients in whom paired liver biopsy specimens were available, the histology activity index (HAI) improved in 12. Therapy was generally well tolerated although 11 patients had to stop therapy because of side-effects, which were more common in cirrhotic patients. In conclusion, our results suggest that long-term administration of ribavirin is well tolerated and may be beneficial in controlling the progression of chronic hepatitis C. This may represent an alternative therapy in patients who have contraindications for interferon therapy or as a palliative approach in non-responders to IFN.

Adult↗
PubMed1998

Clinical evaluation of the branched DNA assay for hepatitis B virus DNA detection in patients with chronic hepatitis B lacking hepatitis B e antigen and treated with interferon-alpha.

The aim of this study was to evaluate the Chiron branched DNA (bDNA) assay for detection of serum hepatitis B virus (HBV) DNA in patients with chronic hepatitis B lacking hepatitis B e antigen (HBeAg) and undergoing interferon (IFN) therapy. Results obtained with the bDNA assay were compared with those obtained using the Abbott liquid hybridization (LH) assay and the polymerase chain reaction (PCR). Serial samples (274) from 34 patients were analysed. Analysis of variance results indicated that bDNA values were more significantly correlated than LH values with both PCR positive/negative results (probability of artifact (Prob > F) = 0.7 and 0.09 for LH and bDNA assays, respectively) and presence/absence of precore mutations (Prob > F = 0.21 and 0.001 for LH and bDNA assays, respectively). Both bDNA and LH results correlated highly with alanine aminotransferase (ALT) values (both had Prob > F values of 0.0) while PCR was not correlated with ALT (Prob > F = 0.05). In 26 evaluable patients, a model based on a generalized Knodell score was used to predict response to IFN therapy, as defined by normalization of ALT values during therapy. This model discriminated well between non-responders and responders. The bDNA results correlated well with the generalized Knodell score, while the LH results did not (Prob > F = 0.04 and 0.19 for the bDNA and LH assays, respectively). In conclusion, the bDNA assay appears to be useful for quantification of HBV DNA levels in HBeAg-negative chronic hepatitis as it correlates with biochemical and histological indications of disease severity as well as with response to IFN therapy.

Analysis of Variance↗
PubMed1998

Inhibitory effect of 2'-fluoro-5-methyl-beta-L-arabinofuranosyl-uracil on duck hepatitis B virus replication.

The antiviral activity of 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil (L-FMAU), a novel L-nucleoside analog of thymidine known to be an inhibitor of hepatitis B virus (HBV) replication in hepatoma cells (2.2.1.5 cell line), was evaluated in the duck HBV (DHBV) model. Short-term oral administration (5 days) of L-FMAU (40 mg/kg of body weight/day) to experimentally infected ducklings induced a significant decrease in the level of viremia. This antiviral effect was sustained in animals when therapy was prolonged for 8 days. The histological study showed no evidence of liver toxicity in the L-FMAU-treated group. By contrast, microvesicular steatosis was found in the livers of dideoxycytidine-treated animals. L-FMAU administration in primary duck hepatocyte cultures infected with DHBV induced a dose-dependent inhibition of both virion release in culture supernatants and intracellular viral DNA synthesis, without clearance of viral covalently closed circular DNA. By using a cell-free system for the expression of an enzymatically active DHBV reverse transcriptase, it was shown that L-FMAU triphosphate exhibits an inhibitory effect on the incorporation of dAMP in the viral DNA primer. Thus, our data demonstrate that L-FMAU inhibits DHBV replication in vitro and in vivo. Long-term administration of L-FMAU for the eradication of viral infection in animal models of HBV infection should be evaluated.

Administration, Oral↗
PubMed1998

Liver fibrosis in unisexual murine Schistosomiasis: quantitative study and morphological changes in mice with chronic infection.

The main complication of Schistosomiasis is the development of liver fibrosis as a result of periovular granuloma in portal tract. This study was undertaken to evaluate the role of the worms in the liver, using the unisexual murine schistosomiasis model. Hepatic fibrosis and histopathological lesions were sequentially followed for 65 weeks in mice experimentally infected with male Schistosoma mansoni. Morphological study revealed that, from the 25th week post-infection, a diffuse fibrosis affected the main branches of the portal vascular system following the host inflammatory reaction, associated with the proliferation of myofibroblasts in situ. Quantitative methods confirmed that an increase of fibrotic deposit occurred during chronic unisexual infection from 25 to 50 weeks post-infection, as compared to controls (35.06 +/- 3.55% versus 27.41 +/- 2.56%) suggesting that antigenic substances secreted by adult schistosomes, in the absence of any eggs, might initiate periportal and perisinusoidal fibrous reaction. The cytokine production and the evolution of inflammation towards fibrosis involves stellate cells and myofibroblasts stimulation. This fibrotic process consequently traduces a reparative phenomenon of the liver.

Actins↗
PubMed1998

Differential pathogenic effect of two Helicobacter-like organisms in dog gastric mucosa.

Two forms of Helicobacter were detected in the gastric mucosa of twelve healthy beagle dogs. According to ultrastructural criteria they could be classified as Helicobacter bizzozeronii-like and Helicobacter felis-like species. In five animals, the light fundic load of Helicobacter bizzozeronii-like did not affect the integrity of the glandular epithelium. In three animals, the heavy bacterial load extended in the lumens of antral glands and coincided with increased intraepithelial lymphoid infiltrate. The heavy bacterial load observed in 4 animals was mixed (Helicobacter bizzozeronii-like and Helicobacter felis-like), fundic and antral, luminal and intracellular. Adherence of Helicobacter felis-like to epithelial cells and intracellular penetration were responsible for focal necrosis, and glandular atrophy might be observed. Helicobacter bizzozeronii-like thus appeared non pathogenic in beagle dogs, even when the heavy bacterial load extended to the antrum. By contrast, Helicobacter felis-like showed a constant pathogenic effect linked to its properties of adhesion and penetration into epithelial cells. A wider comparative study in humans and domestic carnivorous will determine if the latter may play a role of reservoir-host for pathogenic bacteria.

Animals↗
PubMed1997

Pilot study of the combination of interferon alfa and ribavirin as therapy of recurrent hepatitis C after liver transplantation.

Recurrent hepatitis C virus (HCV) in liver transplant patients is a major cause of graft loss, liver failure, and need for retransplantation. The results available to date with the use of interferon alfa (IFN-alpha) in the treatment of recurrent HCV in liver transplant patients have been disappointing. The aim of this study was to evaluate the efficacy and clinical utility of post-transplant combination therapy with IFNalpha2b (3 million units 3 times weekly) and oral ribavirin (1,200 mg/d) for a duration of 6 months, followed by maintenance with ribavirin alone for an additional 6 months. Twenty-one liver transplant recipients with recurrent hepatitis C infection (HCV-RNA-positive; active hepatitis without rejection on biopsy) were enrolled in this study. Pretreatment serum alanine transaminase (ALT) levels were at least two times the upper limit of normal. Before treatment, all patients were HCV-RNA-positive and mean HCV-RNA titers were 125 million genome-equivalents/mL. Mean pretreatment histological score was 6.3 +/- 2. After 6 months of combination therapy, all 21 patients had normal ALTs. Ten patients (48%) cleared HCV-RNA from their serum, as assessed by polymerase chain reaction (PCR), and HCV-RNA levels decreased significantly in the others (P = .0001). Improvement in histological score was seen in all patients after combination therapy (P = .0013). During maintenance ribavirin monotherapy, ALT remained normal in all but 1 of the 18 patients who tolerated therapy. HCV-RNA reappeared in 5 patients, but HCV-RNA levels did not return to pretreatment levels (P = .0004). Comparison of pretreatment and postribavirin monotherapy liver biopsies revealed improvement in all but 1 of the 18 patients who tolerated ribavirin (P = .0002). Side effects were restricted to anemia, which necessitated cessation of ribavirin therapy in 3 patients. No patient experienced graft rejection during the study period. These results are significantly better than those reported with IFN-alpha monotherapy. Most importantly, there was a complete absence of graft rejection. These results suggest that the combination of IFN-alpha and ribavirin is effective in reducing HCV-RNA levels and ameliorating hepatocellular injury in recurrent HCV after liver transplantation, and that maintenance therapy with ribavirin monotherapy can maintain the biochemical and histological response.

Adult↗
PubMed1997

The isolated perfused porcine liver: assessment of viability during and after six hours of perfusion.

Isolated liver perfusion was developed for the study of liver physiology and preservation. The recent development of new perfusion devices and appropriate liver preservation solutions prompted us to reconsider liver perfusion for the specific purpose of evaluating viability in terms of biochemical changes, paying special attention to modifications in the histological ultrastructure. Twenty-two isolated pig livers were perfused with autologous blood. Arterio-portal perfusions were carried out using an extracorporeal perfusion circuit with a hollow fibre membrane oxygenator. Four groups of pig livers were studied using three different liver flushing solutions [Ringer's lactate, ELOHES, and University of Wisconsin (UW)] and two different oxygenation modalities. Liver function tests and histological studies were done. Our results revealed that a high partial oxygen pressure (PO2) level was deleterious to the ultrastructural elements of hepatocytes, in particular to the mitochondria. It was also associated with deficient metabolic performance, i.e., poor bile production and lack of aerobic metabolism. Normal blood gas values could be obtained with the use of air for liver oxygenation. Flushing of the liver with Ringer's lactate or a macromolecular solution such as ELOHES was associated with severe liver cell injuries, as reflected by a marked rise in liver enzymes and histological lesions. Satisfactory results were obtained when UW solution was used for liver harvesting. We conclude that an appropriate liver preservation solution, normal blood gas values, and normal physiological arterio-portal pressure and blood flow are essential for appropriate liver function with preservation of liver architecture and of hepatocyte ultrastructures. Total bilirubin in bile and Factor V are sensitive indicators of good liver function.

Animals↗
PubMed1997

Quantitative studies on liver fibrosis and alpha-smooth muscle actin expression in heroin abusers.

Lobular hepatic fibrosis and the presence of myofibroblasts were studied in heroin abusers, by quantitative automatic image analysis. Nineteen addicts (DA) and thirteen patients having stopped consumption (exDA) were compared to a non-addict group (CONTROL). Addicts, all anti-HIV and HBsAg negative, showed increased transaminase levels. Hepatitis C markers were ot available, at the time of biopsy. The surface of the centrolobular fibrosis, measured on picrosirius stained slides, was respectively 1.9 and 3.5 times larger in DA and exDA than in CONTROL (p < 0.0001). Immunolabelling with an alpha-smooth muscle actin antibody (alpha-SMA) revealed stellate cells in a perisinusoidal location, mainly in areas of matrix thickening in the space of Disse. Morphometric analysis of alpha-SMA expression showed significant differences between the three groups of patients, p < 0.0001 (CONTROL: 198.06 +/- 5.59 microns2; DA: 2227.91 +/- 88.02 microns2; exDA: 3469.10 +/- 154.98 microns2). The surface density of collagen and of alpha-SMA reactivity was also significantly different between these groups (p < 0.0001). These data strongly suggest that heroin is responsible for an early and progressive centrolobular liver fibrosis, occurring simultaneously with a myofibroblastic response. It might represent a reparative phenomenon arising from a direct vascular injury, leading to an impairment of blood-hepatocyte exchange.

Actins↗
PubMed1997

[Efficacy of interferon alpha in primary prevention of preneoplastic lesions in a transgenic murine model of hepatocellular carcinoma related to the interaction between woodchuck hepatitis viruses and c-myc oncogene].

OBJECTIVES: C-myc oncogene overexpression by near insertion of hepatitis B virus is important in woodchuck hepatocarcinogenesis. This DNA fragment was transferred in mice who developed hepatocellular carcinoma via preneoplastic lesions. In the present study, we tested the preventive effect of alpha interferon on the incidence of hepatocyte dysplasia. METHODS: Human recombinant alpha interferon hybrid B/D was continuously administered at increasing doses (0 to 10,000 IU/g) in a transgenic mouse model. One cohort was treated from day 21 to day 80. A histological liver examination was performed and the transgene expression was assessed by hybridization with or without previous genic amplification, and by indirect immunofluorescence. RESULTS: At day 15, histological liver examination was normal. Interferon treatment decreased the expression of viral sequences, but not of c-myc. At day 80, interferon treatment resulted in a reduction of the incidence and severity of dysplasic lesions, and a marked decrease in c-myc overexpression. CONCLUSION: In this transgenic mouse model, alpha interferon treatment decreased the incidence and severity of precancerous lesions, due to a reduction in c-myc overexpression. This prophylaxis could be of interest in human hepatocarcinogenesis where c-myc overexpression is frequent.

Animals↗
PubMed1997

[Para-aortic paraganglioma found by arteriography. Apropos of a case and review of the literature].

A 53 years old man had an angiography for suspected renovascular hypertension (arteritis, renal insufficiency, duplex scanning). It showed a narrow right renal artery streched by a 45 mm mass arising from the adrenal. The computed tomography showed the tumor and the nuclear magnetic resonance imaging indicated a pheochromocytoma. The patient had no complain of headaches, palpitations or sweating. Biochemistry was normal except for a slight serum creatinin elevation and a non significant urinary noradrenaline level. A diagnostic of non functioning pheochromocytoma was made. The therapeutics consisted in a surgical ablation of the tumor and the right kidney (non functioning) and the patient became normotensive thereafter without treatment. The histologic feature was an aortico-sympathetic paraganglia, the adrenal was normal. Paraganglias are arising from the paraganglion system including chemodectoma and glomus jugulare tumor. Non functioning retroperitoneal paraganglias are uncommon: less than 50 in the literature between 1902 and 1992.

Aorta, Abdominal↗
PubMed1997

[Favorable course of hepatitis B virus reactivation with hepatocellular insufficiency by a treatment combining corticoids, foscarnet and ganciclovir].

Reactivation of hepatitis B virus replication is a rare event during the natural history of chronic hepatitis B. However, the clinical presentation may be severe and an effective therapeutic protocol must be established. We report a case of spontaneous reactivation of hepatitis B virus infection with liver failure. For the moment, no medical treatment has been defined in this situation. A combination of corticosteroids and antiviral drugs (foscarnet and ganciclovir) resulted in clinical and biological recovery, and HBV elimination. If the efficacy of this combined treatment is confirmed in a larger population, this new physiopathological approach should be considered whenever life threatening liver failure occurs.

Adult↗
PubMed1996

The carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) is a potential serum marker of ongoing liver fibrosis.

We report for the first time the measurement of the serum concentration of the carboxy-terminal cross-linked telopeptide of type I collagen in patients with various liver diseases. This breakdown product of type I collagen, which is the major collagen type found in fibrotic liver, was measured by a radioimmunoassay in the serum of 149 patients with various liver diseases and in 67 controls. Its concentration is significantly elevated (P < 0.05) above reference intervals in sera from patients with liver diseases, except in patients with chronic active hepatitis of unknown origin and in patients with acute hepatitis A. In the 143 patients with liver fibrosis, the serum level of the carboxy-terminal telopeptide of type I collagen is correlated with the extent of fibrosis, as assessed by a histological scoring system (r = 0.3899, P < 0.0001), but not with inflammation and necrosis.

Adult↗
PubMed1996

In situ detection of human cytomegalovirus DNA in gastrointestinal biopsies from AIDS patients by means of various PCR-derived methods.

The development of new in situ assessment of HCMV disease on endoscopical gastrointestinal biopsies from AIDS patients is described and compared with the viral load measured by semiquantitative solution-phase PCR (SQ-PCR). Ten biopsies were examined by viral isolation, standard histology, in situ hybridization (ISH), in situ PCR-hybridization (PCR-ISH) and SQ-PCR, using the same target sequence. The methods developed for in situ HCMV detection were HCMV primers, the plasmid pCMV 406-S, a vector-free-digoxigenin-labelled HCMV-362 probe and the pSK + MCS nonsense probe. Paraffin-embedded MRC5 cells, either HCMV-infected or uninfected served as controls of specificity for ISH. beta-Actin primers were designed as markers of DNA integrity. Computerized models of the PCR, solution-phase and in situ PCR on formalin-fixed DNA indicated that HCMV and beta-actin primers were efficient and specific. Nine biopsies were negative for HCMV by histology and virus isolation. SQ-PCR revealed 80,000; 80 and < 80 HCMV genomic equivalents in 6, 2 and 2 biopsies, respectively. In 8 biopsies, both ISH and PCR-ISH identified positive nuclei in the intestinal epithelium, with sparing of the lamina propria. This indicates that an improvement in in situ methods can help the timely diagnosis of HCMV infection. Direct in situ PCR with beta-actin primers showed a positive signal in all the nuclei in the tissue sections, whereas omission of Taq polymerase resulted in an absence of signal, implying optimal in situ PCR. The data suggest an early-stage reactivation of HCMV, possibly harboured in the intestinal epithelium.

AIDS-Related Opportunistic Infections↗