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Biomedical subjects

M Fabre

Publications and source records attributed to M Fabre.

At least 127 records · Page 7Linked to original sources
PubMed1994

[Exudative gastropathy associated with cytomegalovirus infection after allogenic bone marrow transplantation].

The authors report a case of protein losing gastropathy associated with cytomegalovirus. This form which is extremely rare in adults occurred alone after allogenic bone marrow transplantation and become apparent by a hypoalbuminaemia causing oedema of the lower limbs. Gastrocopy showed large red folds of approximately a centimetre covered in a whitish hypersecretion coating. Biopsy demonstrated active gastritis which appeared on a hypertrophic and hypersecretive gastritis. Outcome was favourable within 3 months without treatment.

Adult↗
PubMed1993

Failure to obtain hybridomas between human macrophages and human tumoral U-937 cells is probably due to parental macrophages.

Despite more than 50 attempts and the use of various methods, it has been impossible to establish homologous hybridomas between human mature macrophages and 8-azaguanine-resistant U-937 clones prepared in the laboratory. To rule out the possibility that these clones were unsuitable for the selection of hybrids, a study of their properties was done. It was shown that U-937 wild type cells were able to produce HPRT, whereas 8-azaguanine (8-aza)-resistant clones did not. Curiously, exonic and intronic HPRT sequences were undetectable both in wild type and in 8-aza-resistant cell genomes, under conditions where they were detected in control cells. Chromosome analysis of the clone UM9, one of the most frequently used in fusion experiments, revealed many qualitative and quantitative differences with the U-937 wild type cells. 8-aza-resistant U-937 cells were capable of fusion with human macrophages and gave rise to heterokaryons and probably to synkaryons, which survived for weeks without dividing in hypoxanthine-aminopterin-thymidine medium. The results could be interpreted in terms of the existence of a transacting negative regulatory mechanism of the macrophage genome on the proliferative capacity of homospecific hybridomas.

Animals↗
PubMed1993

HBV infection in pediatric liver transplantation.

When hepatitis B virus (HBV) infection precedes orthotopic liver transplantation (OLT), an important issue is to avoid post-OLT HBV infection of the transplanted liver. When HBV infection is found after OLT, the main objective is to prevent the complication of cirrhosis. A study of HBV infection in 162 liver-transplanted children followed at Hôpital de Bicêtre is presented here. One hundred forty-one of these children were completely vaccinated against HBV; 89% of them still disposed of protective titers of serum antibodies to hepatitis B surface antigen (anti-HBs) (> 10 IU/L) 6-60 months after OLT. Four children had a HBV-associated liver disease that required OLT. In these children a passive immunoprophylaxis maintaining serum anti-HBs levels > 100 IU/L allowed three of them to remain free of serum hepatitis B surface antigen (HBsAg) and HBV-DNA during follow-up at 10, 20, and 36 months. Four other children have been found to be HBsAg+ after OLT, but it was not clear whether the source of HBV was a reactivation or a de novo infection. Low doses of cyclosporin and prednisone were administered, in order to avoid the complications of HBV infection. Liver needle biopsies in three of these patients 37, 42, and 46 months after OLT showed a moderate chronic active hepatitis and mild fibrosis. Immunostaining for HBs and hepatitis B core (HBc) antigens indicated active viral replication.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1993

The tumor promoter 12-O-tetradecanoylphorbol-13-acetate blocks differentiation of HT-29 human colon cancer cells.

Recently developed HT-29-derived cell lines, which display variable differentiated phenotypes provide an invaluable opportunity to analyze the mechanism by which cell differentiation is regulated in the intestine. We have studied the effects of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in the differentiation phenotype of mucus-secreting (HT-29 M6) and absorptive (HT-29 M3) cells. TPA prevented the accumulation of differentiation markers such as dipeptidylpeptidase IV, villin or mucins, down-regulated the expression of these molecules in post-confluent differentiated cell cultures and induced the loss of the functional integrity of the tight junction in the monolayer (i.e. decreased transepithelial resistance and inhibited dome formation). These effects were mediated by activation of protein kinase C (PK-C), as demonstrated using the specific inhibitor GF109203x. Analysis by immunoblotting of the PK-C isoforms present in HT-29 M6 cells revealed that the most abundant TPA-sensitive isoform was PK-C epsilon, although low levels of cPK-C were also detected. Further studies are necessary to elucidate the role of the different PK-C isoforms in the differentiation of HT-29 cells.

Biomarkers↗
PubMed1993

Phorbol ester-induced scattering of HT-29 human intestinal cancer cells is associated with down-modulation of E-cadherin.

The effects of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) on the growth characteristics of the colon cancer cell line HT-29 M6 were studied. TPA induced the scattering of proliferative HT-29 M6 cells: in the presence of the phorbol ester, HT-29 M6 colonies scattered and the cells acquired a flatter aspect with diminished cell-cell contacts. This effect of TPA required a persistent activation of PK-C and was accompanied by a slight decrease (30%) in the growth rate. Modifications by TPA of two scattering associated properties of these cells were also detected: TPA decreased cell-to-cell aggregation and enhanced the cellular attachment to matrix substrata (collagen, laminin). The decrease in cell-to-cell adhesion was correlated with a loss of cellular E-cadherin as evidenced by immunofluorescence or immunoblotting with a specific monoclonal antibody. Cell scattering was dependent on the extracellular concentration of Ca2+; an increase from 1.6 to 10 mM in the concentration of this ion completely blocked the morphological effects of TPA as well as its action on cell aggregation. This high concentration of Ca2+ also prevented the down modulation of E-cadherin as determined by immunofluorescence. However, the TPA-induced increase in cell attachment to the matrix was not affected by high calcium. These findings support the importance of altered cell-cell adhesion in the process of scattering and provide a good system for the study of down modulation of E-cadherin, a protein involved in the control of cell growth, differentiation and invasion of epithelial cells.

Cadherins↗
PubMed1993

[Chronic active hepatitis and cirrhosis induced by wild germander. 3 cases].

We report 3 cases of chronic liver injury that were observed after prolonged treatment with wild germander, a herbal medicine recently prohibited by French Ministry of Health, following several reports suggesting its hepatotoxicity. Chronic active hepatitis was found in 2 cases, and active cirrhosis in 1 case. The onset of hepatitis occurred after 6 to 7 months of treatment. Serum anti-nuclear and anti-smooth muscle antibodies were present in 2 patients. In 2 cases, wild-germander involvement was recognized several months after appearance of liver injury. Following treatment discontinuation, outcome was favorable in the 3 patients. These observations suggest that diagnosis of acute or chronic liver injury of unknown origin should always include the search for herbal medicine treatment.

Adult↗
PubMed1992

Intrahepatic bile duct damage in children with Kawasaki disease.

Three children with Kawasaki disease had liver biopsies because of evidence of hepatic disease. Cholangitis or bile duct injury and proliferation were found. Similar damage to the hepatic ductular system may explain the hydrops of the gallbladder sometimes seen in this disease.

Bile Ducts, Intrahepatic↗
PubMed1992

Effects of ascorbate-deficiency on collagen secretion and resorption in cultured mouse incisor germs.

The effects of ascorbic acid deficiency on mouse incisors, grown in vitro, has been investigated at the histological and cytological levels. In this model, continuously growing mouse incisors are characterized by the existence of different type of predentin-dentin matrix on its lingual (root-analogue) and labial (crown-analogue) surface and the absence of enamel on the lingual surface. Our observations indicated that ascorbate-deficiency affected the behavior of mouse tooth germs in vitro: odontoblast differentiation was disturbed and morphological evidence for odontoblast-mediated collagen resorption were observed. An abnormal amorphous predentin-dentin matrix existed and the basement membrane was prematurely disrupted. The dentin mineralization, as well as functional differentiation of ameloblasts were strongly hampered. Chronic deficiency led to disorganization of the dental tissues.

Absorption↗
PubMed1992

Unilateral benign medulloepithelioma associated with bilateral retinal detachment.

A two-month-old girl presented with a unilateral benign cystic medulloepithelioma from the ciliary body associated with bilateral retinal non-attachment. The authors discuss the histopathologic findings and the pathogenesis of the congenital retinal non-attachment: are these incidental occurrences or do they arise from a common pathogenetic mechanism?

Ciliary Body↗
PubMed1992

Overexpression of p53: a rare event in a large series of white patients with hepatocellular carcinoma.

Mutant p53 has been found in a wide variety of human malignancies including carcinomas of the lung, breast and colon. Because of the controversial mutational rate of the p53 gene in hepatocellular carcinoma, a large series of liver tumors from white patients with different risk factors was examined immunohistochemically for expression of the p53 mutant to assess its prevalence and the relationships between p53 overexpression and clinicopathological data. Nine of 58 specimens were found to have detectable evidence of p53 gene mutation by virtue of the immunohistochemical detection of mutant p53 protein. The p53 mutation was more frequent in patients with serological hepatitis B and C markers than in patients without these markers (p = 0.046). The prevalence of p53-positive tumors was also significantly higher in the group of tumors with invaded portal branches than in the group without (p = 0.02). Our results showed that p53-positive hepatocellular carcinoma is a rare finding in patients exposed to a low dietary aflatoxin intake and that p53 mutation seems to occur at a late stage of the tumoral process and could contribute to an aggressive tumoral phenotype.

Adult↗
PubMed1991

Ultrastructural similarities between epidermal Langerhans cell Birbeck granules and the surface-connected canalicular system of EDTA-treated human blood platelets.

Birbeck granules characterize under the electron microscope epidermal Langerhans cells. These distinctive pentalaminar organelles are indeed not detectable in the possible precursors of human Langerhans cells and tend to disappear in cultured human Langerhans cells. The mechanisms that lead to the appearance of Birbeck granules in epidermal Langerhans cells and to their later disappearance still remain unknown. In the present study we show that the more or less dilated elements of the surface-connected canalicular system of human blood platelets collapse after EDTA treatment. Made up of two parallel limiting membrane and central irregular striated density, these elements show great ultrastructural similarities with the Birbeck granules of human epidermal Langerhans cells. These platelet morphologic changes i) are directly dependent on the EDTA-induced dissociation of the glycoprotein GP IIb-IIIa, the platelet-specific calcium-dependent heterodimer complex, member of the beta 3 integrin subfamily (alpha IIb beta 3) and ii) apparently result from a cross-linking of the dissociated glycoproteins. These findings lead us to propose that in the same manner cells of the Langerhans lineage, on reaching the epidermis, will find themselves in contact with an epidermal specific ligand. Interactions between this epidermal ligand and Langerhans cell receptors could then induce, all along the circuit taken by the ligand-receptor complexes, morphologic modifications, i.e., appearance of structures of Birbeck granule type.

Blood Platelets↗
PubMed1991

[Nodular regenerative hyperplasia and primary biliary cirrhosis].

We report two cases of nodular regenerative hyperplasia of the liver associated with primary biliary cirrhosis. Cholestasis and presence of antimitochondrial antibodies were noted in both patients. In one patient, the diagnosis of nodular regenerative hyperplasia was supported by the demonstration of disseminated small hepatic nodules without perinodular fibrosis. Twelve years later, the histopathological picture was one of primary biliary cirrhosis. The other patient presented an histological picture of regenerative hyperplasia of the liver and primary biliary cirrhosis. The association of regenerative hyperplasia of the liver and primary biliary cirrhosis is discussed.

Biopsy↗
PubMed1991

[Hepatic cholesterol ester storage disease. Two new cases diagnosed in adults].

Cholesterol ester storage disease is a rare disorder characterized by an hereditary deficiency of lysosomal acid lipase that induces an accumulation of cholesterol ester in most tissues of the body, particularly in liver. The diagnosis is usually made during childhood. The aim of this article is to report two new cases diagnosed in adult age. Two patients, 25 and 20 years old, respectively, presented with hepatomegaly, a slight to moderate increase in serum transaminases, and esophageal varices. In both cases, diagnosis was based on the presence of hypercholesterolemia, fatty infiltration of the liver with lipid droplets in hepatic parenchymal cells, foamy macrophages, hepatic storage of cholesterol esters, and low activity of lysosomal acid lipase. Histological abnormalities were associated with portal and periportal fibrosis in one patient and a micronodular cirrhosis in the other; these lesions were probably the cause of portal hypertension. Fibrosis of varied degrees has been previously reported in cholesterol ester storage disease. Its mechanism remains unclear.

Adult↗