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Biomedical subjects

P Bedossa

Publications and source records attributed to P Bedossa.

At least 73 records · Page 4Linked to original sources
PubMed1997

MHC-dependent cytolysis of autologous tumor cells by lymphocytes infiltrating urothelial carcinomas.

Tumor-infiltrating lymphocytes (TIL) were grown from 23 urothelial carcinomas. Phenotyping analysis showed that the TIL cultures were mainly CD3+. Although CD4+ and CD8+ T-cell sub-sets were grown in culture, CD4+ T-cell sub-sets predominated over CD8+ T cells. Immunohistochemical studies performed on 5 tumor specimens confirmed this observation, and indicated that CD4+ T cells surrounded the tumor islets, whereas CD8+ T lymphocytes were localized among the tumor cells. Five short-term carcinoma cell lines established from these urothelial tumors were used as target cells in cytolysis assays in order to investigate the functional anti-tumor activity of autologous TIL. TIL from 4/5 tumors were lytic and 3 TIL lines displayed MHC-class-I-dependent cytotoxicity directed against autologous tumor cells. CD4+ T-cell-depletion experiments performed on TIL line 07 confirmed that CD8+ MHC-class-I-dependent CTL were the predominant effectors. Finally, experiments performed on 6 allogeneic urothelial-cancer cell lines matched for HLA-class-I molecules showed that TIL07 exhibited selective lytic activity toward tumor 07. These data indicate that CD8+ MHC-class-I-dependent CTL present in urothelial carcinomas are functional and may participate in the anti-tumor immune response.

CD3 Complex↗
PubMed1997

Concerted nonsyntenic allelic losses in hyperploid hepatocellular carcinoma as determined by a high-resolution allelotype.

Although the occurrence of loss of genetic material in hepatocellular carcinoma (HCC) has been documented both by cytogenetic analysis and by monitoring of allelic losses, a global overview of the extent and frequency of deletion occurring throughout the genome is not yet available. To contribute to this information, DNAs extracted from flow-sorted aneuploid nuclei from HCC and matched normal DNAs were typed for 275 microsatellite loci that were distributed along the autosomes. An average of 190 (69%) informative loci per case were generated on 48 HCC. Complete loss of heterozygozity in the tumor DNA was observed for 15.6% of the typed loci. The chromosome segments that were most frequently affected by deletion were: 8p (60%), 17p (48%), 1p (44%), 4q (42%), 16p (40%), 16q (39%), 6q (35%), 9p (30%), and 13q (29%). On average, 8 of the 39 chromosome segments studied per tumor carried at least one locus that demonstrated loss of heterozygosity (ie., the fractional allelic loss was 0.21). Groups of concerted nonsyntenic losses were observed for 16p and 1p and for 16p and 4q. The location of putative tumor suppressor genes on the most frequently deleted regions was confirmed and, in some cases, refined.

Adult↗
PubMed1997

Natural history of liver fibrosis progression in patients with chronic hepatitis C. The OBSVIRC, METAVIR, CLINIVIR, and DOSVIRC groups.

BACKGROUND: Our aim was to assess the natural history of liver fibrosis progression in hepatitis C and the factors associated with this progression. METHODS: We recruited 2235 patients from the Observatoire de l'Hépatite C (OBSVIRC) population, the Cohorte Hépatite C Pitié-Salpétrière (DOSVIRC) population, and the original METAVIR population. All the patients had a biopsy sample compatible with chronic hepatitis C as assessed by the METAVIR scoring system (grades the stage of fibrosis on a five-point scale, F0 = no fibrosis, F4 = cirrhosis, and histological activity on a four-point scale, A0 = no activity, A3 = severe activity). No patient had received interferon treatment before the liver biopsy sample was obtained. We assessed the effect of nine factors on fibrosis progression: age at biopsy; estimated duration of infection; sex; age at infection; alcohol consumption; hepatitis C virus C (HCV) genotype; HCV viraemia; cause of infection; and histological activity grade. We defined fibrosis progression per year as the ratio between fibrosis stage in METAVIR units and the duration of infection (1 unit = one stage, 4 units = cirrhosis). FINDINGS: The median rate of fibrosis progression per year was 0.133 fibrosis unit (95% CI 0.125-0.143), which was similar to the estimates from previous studies (0.146 to 0.154). Three independent factors were associated with an increased rate of fibrosis progression: age at infection older than 40 years, daily alcohol consumption of 50 g or more, and male sex. There was no association between fibrosis progression and HCV genotype. The median estimated duration of infection for progression to cirrhosis was 30 years (28-32), ranging from 13 years in men infected after the age of 40 to 42 years in women who did not drink alcohol and were infected before the age of 40. Without treatment, 377 (33%) patients had an expected median time to cirrhosis of less than 20 years, and 356 (31%) will never progress to cirrhosis or will not progress for at least 50 years. INTERPRETATION: The host factors of ageing, alcohol consumption, and male sex have a stronger association with fibrosis progression than virological factors in HCV infection.

Adult↗
PubMed1997

Malignant transformation of nontrophoblastic cells is associated with the expression of chorionic gonadotropin beta genes normally transcribed in trophoblastic cells.

The beta subunit of human chorionic gonadotropin (hCGbeta) is encoded by four nonallelic CGbeta genes. An assay was developed for distinguishing type I CGbeta allelic genes beta7 and beta6, which possess a GCC codon corresponding to an alanine at position 117 of hCGbeta, from type II CGbeta genes beta8, beta5, and beta3 and its allele beta9, which possess a GAC codon corresponding to an aspartic acid at the same position. In normal trophoblast, hCGbeta is encoded by type II CGbeta genes, whereas normal nontrophoblastic tissues of differing histological origin (breast, prostate, skeletal muscle, bladder, adrenal glands, thyroid, colon, and uterus) express only type I CGbeta genes. We studied the expression of CGbeta genes in 86 tumor specimens collected from patients with breast, bladder, prostate, and thyroid cancer and found that up to 61% of these nontrophoblastic tumors expressed type II CGbeta genes. Experiments performed on tumor tissues and their normal counterparts confirmed that the malignant transformation of nontrophoblastic cells is associated with the expression of type II CGbeta genes. These findings provide the basis for a simple test (the CG117 assay) that may be useful for the diagnosis of the most frequent malignancies.

Cell Line↗
PubMed1997

Evidence for the polyclonal nature of focal nodular hyperplasia of the liver by the study of X-chromosome inactivation.

Focal nodular hyperplasia (FNH) of the liver is a benign tumor commonly considered as a reactive disorder related to a pre-existing vascular malformation. However, the pathogenesis of this lesion has been recently discussed. To determine whether FNH is a polyclonal or a clonal lesion, we investigated the inactivation pattern of the X chromosome, using molecular genetic analysis of the DNA methylation pattern at a polymorphic site on the human androgen receptor gene (HUMARA). Fifteen FNH were studied, and results were compared with those obtained from 7 hepatic adenomas (HA) and 2 hepatocellular carcinomas (HCC). DNA was extracted from both lesional and nonlesional livers, fixed, and paraffin-embedded. To assess the methylation pattern, we used a quantitative fluorescent polymerase chain reaction (PCR) procedure that allows for the accurate measurement of the peak intensities of each allele. Three patients were noninformative because they were homozygous at the HUMARA locus. According to the threshold for monoclonality established by a titration curve, all FNH showed a random pattern of X-chromosome inactivation consistent with a polyclonal lesion. In contrast, all but 1 hepatic adenoma and all hepatocellular carcinomas were clonal, as shown by the nonrandom pattern of X-chromosome inactivation observed in these cases. In conclusion, these results suggest that FNH should be considered as a reactive disorder rather than as a tumoral proliferation. Discordant results recently observed in the literature could be at least in part explained by methodological differences in the PCR procedure.

Adenoma↗
PubMed1997

Age and platelet count: a simple index for predicting the presence of histological lesions in patients with antibodies to hepatitis C virus. METAVIR and CLINIVIR Cooperative Study Groups.

The aim of this study was to identify clinical and biological factors associated with histological lesions in patients with chronic hepatitis C and to construct a simple diagnostic index. A database consisting of 500 patients with untreated biopsy-proven chronic non-A non-B hepatitis was used. Liver biopsies were reviewed, blind, by a panel of pathologists. Patients were classified according to the presence of necroinflammatory lesions (histological activity) and fibrosis. The diagnostic value of nine clinical and 10 biological factors was assessed using logistic regression analysis, sensitivity, specificity and predictive values, and a score was constructed combining the most significant factors identified. The validation used an independent population of 120 patients. Serum platelet concentration and age were the two main factors significantly and independently correlated with the presence of fibrosis and/or histological activity. A simple score referred to as AP, combining age and platelet count, varied from 0-10. For the presence of significant histological disease (moderate to severe necroinflammatory lesions and/or septal fibrosis to cirrhosis), an AP score of 6 or more had a specificity of 0.93 and a sensitivity of 0.52%. In the validation population, the area under the curve was 0.690 +/- 0.085, not significantly different from that of the first population, 0.763 +/- 0.043. Hence, a simple score combining age and platelet count enabled the accurate prediction of the presence of activity and fibrosis in patients infected with the hepatitis C virus. When this score reached 6, liver biopsy could be avoided owing to its high predictive value. However, the negative predictive value was not high enough to prevent a liver biopsy in patients with a lower score.

Adult↗
PubMed1997

Noninvasive diagnosis of hepatic fibrosis or cirrhosis.

BACKGROUND & AIMS: The evaluation of the degree of hepatic fibrosis is especially important in patients with chronic liver disease. The aim of this study was to study the diagnostic accuracy of noninvasive means. METHODS: Sixty-three clinical, biochemical (prothrombin index, gamma-glutamyl transpeptidase and apolipoprotein A1 levels [PGA score]; and hyaluronate, alpha2-macroglobulin, N-terminal peptide of type III procollagen, laminin, and transforming growth factor beta1 levels), Doppler ultrasonic, and endoscopic variables were recorded in 243 patients who were divided into four groups: whole, compensated, alcohol-compensated, and viral-compensated liver disease. Diagnostic accuracy was evaluated by discriminant analysis; first globally, then by stepwise analysis. RESULTS: In three groups, hyaluronate and prothrombin index were the best predictive factors (accuracy, > or =85%). Accuracy for the diagnosis of cirrhosis varied from 89.5% to 95% with global discriminant analysis and from 91% to 94% with stepwise analysis according to the group. In the compensated group, hyaluronate concentration of > or =60 microg/L had a sensitivity of 97% and a specificity of 73%. Diagnostic accuracy was 87% globally for extensive fibrosis. Prothrombin index and hyaluronate were two independent variables predictive of the area of fibrosis (r2 = .66). CONCLUSIONS: With the use of a few noninvasive criteria, cirrhosis can be correctly diagnosed in 91%-94% of patients with chronic liver disease. Serum hyaluronate concentration is the most sensitive variable for screening.

Aged↗
PubMed1997

In situ detection of lipid peroxidation by-products in chronic liver diseases.

Lipid peroxidation is an autocatalytic mechanism leading to oxidative destruction of cellular membranes. The deleterious consequences of this mechanism are related in part to the formation of reactive aldehydic products that bind to intra- or extracellular molecules to form adducts. Specific antibodies directed against malondialdehyde (MDA) and 4-hydroxynonenal (HNE) adducts, major aldehydic metabolites of lipid peroxidation, allowed us to investigate in situ, with an immunohistochemical procedure, the occurrence of lipid peroxidation in a panel of different chronic liver diseases. Intracellular HNE and MDA adducts were detected respectively in 24 of 39 cases (62%) and in 12 of 34 cases investigated (35%). They were localized mainly in the cytoplasm of hepatocytes, with the strongest staining observed in hemochromatosis, Wilson's disease, and in areas of acute alcoholic hepatitis in cases of alcoholic liver diseases. A peculiar pattern of immunostaining was observed in primary biliary cirrhosis where biliary cells of destroyed but also intact bile ducts strongly expressed HNE adducts. The liver extracellular matrix also displayed MDA adducts (30 of 34 cases, 88%) and HNE adducts (23 of 39 cases, 59%). While HNE adducts were specifically localized on large bundles of collagen fibers, MDA adducts were detected in a thin reticular network and in sinusoidal cells around portal tracts or fibrous septa. In conclusion, lipid peroxidation by-products are detectable in chronic liver diseases. Immunohistochemical results suggest that this mechanism is implicated very early in the pathogenesis of some of these diseases.

Adolescent↗
PubMed1997

Chromosomal aberrations in hepatocellular carcinomas: relationship with pathological features.

Fluorescence in situ hybridization performed on tissue sections can reveal chromosomal abnormalities related to histopathological features. This technique was performed on serial frozen sections from seven normal livers and 29 hepatocellular carcinomas (HCCs) using pericentromeric repeat-specific probes for chromosomes 1, 4, 6, 7, 8, 16, and 17. For each HCC and each probe, the percentage of cells showing one, two, or more than two signals was counted and compared with the distribution in the normal liver. According to these results, HCCs were categorized as monosomic, disomic, or polysomic (more than two signals) for the chromosome tested. These data were compared with the main histopathological characteristics of HCC. Chromosome gains were very common, preferentially affecting chromosome 1 (23 of 27 cases, 85%), chromosome 16 (16 of 27 cases, 59%), chromosome 7 (16 of 29 cases, 55%), chromosome 6 (15 of 29 cases, 52%) and chromosome 8 (14 of 29 cases, 48%). Monosomy was seen more rarely, affecting preferentially chromosome 16 (19%), chromosome 17 (14%), and chromosome 4 (10%). A significant correlation was observed between aneusomy of chromosome 4 and tumor size (P < .05) or the presence of vascular embolism (P < .05). In conclusion, chromosomal gains are frequent genetic events in human HCC. A significant association between a gain in chromosome 4 and large tumor size or vascular embolism suggests that this genetic abnormality is a late event in liver carcinogenesis.

Adult↗
PubMed1997

In situ detection of lipid peroxidation in chronic hepatitis C: correlation with pathological features.

AIMS: To assess the occurrence of lipid peroxidation in chronic hepatitis C and to evaluate its relation to pathological features and liver iron concentrations. METHODS: Liver biopsy samples of 43 patients with untreated chronic hepatitis C were studied by immunohistochemistry using specific antibodies directed against two major aldehyde metabolites of lipid peroxidation, malondialdehyde (MDA), and 4-hydroxynonenal (HNE). RESULTS: MDA and HNE adducts (aldehydes covalently linked to another molecule) were detected in the liver samples in 77% and 30% of cases, respectively. MDA adducts were detected both in the extracellular matrix and sinusoidal cells localised in areas of periportal and lobular necrosis. HNE adducts appeared in the cytoplasm of only a few hepatocytes. Comparison of the semiquantitative assessment of adducts (MDA and HNE indexes) with the grading and the staging of chronic hepatitis showed that the MDA index was correlated with fibrosis score (p < 0.001) and the grade of activity (p < 0.01). There was also a tendency to correlation with liver iron concentration (p = 0.09). No correlation was observed between the HNE index and pathological features or liver iron concentration. CONCLUSION: Lipid peroxidation products are detectable in the liver of chronic hepatitis C patients. The presence of MDA adducts in areas of active fibrogenesis and the correlation between the MDA index and fibrosis score suggest a role for lipid peroxidation in liver fibrosis.

Adult↗
PubMed1997

Identification of pro-EPIL and EPIL peptides translated from insulin-like 4 (INSL4) mRNA in human placenta.

Recently, a new member of the insulin gene superfamily termed insulin-like 4 (INSL4) was identified in the human placenta and uterus. The present study investigated whether placenta translates INSL4 mRNA into a putative peptide named early placenta insulin-like (EPIL). Among antibodies elicited against the C chain of pro-EPIL, one antibody (AB7381) was specifically directed against the C chain 59-88 portion, and among those elicited against the A and B chains of EPIL, one antibody (Ab1661) was directed against the A chain 115-139 and the B chain 23-52 portions. Immunohistochemistry based on antibody 7381 to pro-EPIL and antibody 1661 to EPIL demonstrated that the cytotrophoblast from early placenta preferentially expresses the pro-EPIL peptide, whereas the EPIL peptide is expressed by both the cytotrophoblast and the syncytiotrophoblast. At term, the pro-EPIL peptide was detected in villous cytotrophoblast cells, whereas the EPIL peptide was not detected. Moreover, in vitro experiments performed on term placenta showed that the steady state levels of INLS-4 mRNA in the cytotrophoblast are 10 times (one log unit) lower than in the differentiated villous syncytiotrophoblast cells. Taken together, these findings reveal that expression of EPIL peptides in the villous cytotrophoblast is different from that displayed by the syncytiotrophoblast. Finally, these data are the first demonstration that INSL4 mRNA are translated into pro-EPIL and EPIL peptides.

Amino Acid Sequence↗
PubMed1997

[Localization of a tumor suppressor gene distal to D22S270 in colorectal cancers].

Recurrent allelic losses on chromosome 22q have been reported in colorectal cancer, distal to the NF2 gene, suggesting that another tumor suppressor gene might be involved. We report here the typing of 256 sporadic colorectal tumors and 18 colonic cancer cell lines using a set of chromosome 22 polymorphisms, ranging from 20 to 45. A panel of somatic cell hybrids, that allows to distinguish 11 bins in the 22q13 region, was used to localize 19 of the 45 selected markers and the putative tumor suppressor gene BZRP. Allelic-loss was observed in 43% of tumors. The minimal region of deletion that could be determined, telomeric to locus D22S270, refines significantly the position of the gene. The localization of the BZRP gene in this region led to a systematic screening for somatic point mutation. Direct sequencing of its coding sequence in 36 tumors hemizygous for chromosome 22 allowed the identification of three polymorphisms but failed to detect somatic mutation.

Adenocarcinoma↗