Biomedical subjects

F Muzeau

Publications and source records attributed to F Muzeau.

22 records · Page 2Linked to original sources

PubMed1992

Cytokine effects in a human colonic goblet cell line. Cellular damage and its partial prevention by 5 aminosalicylic acid.

The aim of the present study was to investigate the effects of cytokines on intestinal goblet cells in vitro. For this purpose, we examined the effects of recombinant interferon gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) on the human colonic goblet cell line Cl.16E by morphological and kinetic studies, and by the assessment of mucus production during IFN-gamma/TNF-alpha treatment. Control cultures of Cl.16E cells grown on nitrocellulose filters formed monolayers of polarized goblet cells, which had kinetic characteristics similar to those of a differentiated epithelium in steady state. The combined action of IFN-gamma and TNF-alpha caused a dose-related cellular exfoliation, leading to the formation of a mucoid cap made of mucus and cellular debris. The remaining viable cells underlying the mucoid cap were cuboidal and devoid of mucus granules. A dose-related increase in cellular incorporation of [3H]thymidine was reactive to the cytokine-induced cell loss. The synergistic effects of IFN-gamm and TNF-alpha were found to be reversible when the cells were reincubated in a culture medium without cytokines. Furthermore, 5-aminosalicylic acid partially protected Cl.16E cells against cellular injury caused by IFN-gamma and TNF-alpha. On the whole, these morphological and kinetic findings argue that the changes induced in Cl.16E cells by IFN-gamma and TNF-alpha closely parallel those observed during the acute phase of ulcerative colitis, and show that these cytokines can regulate intestinal mucus production by modulating cellular exfoliation, thus leading probably to a reinforced protection of the damaged mucosa.

Aminosalicylic Acids↗

PubMed1990

Infected cells and immune cells in the gastrointestinal tract of AIDS patients. An immunohistochemical study of 127 cases.

Human immunodeficiency virus (HIV) proteins were detected by immunohistochemistry in the duodenal and rectal mucosa of 30% of 127 AIDS patients studied. HIV-infected cells were present in the lamina propria in 95% of the positive biopsies. They were immune cells, either isolated lymphocytes and macrophages (1-4 per positive biopsy) or dendritic reticulum cells forming a network in the germinal centres of mucosal lymphoid follicles. HIV proteins were not found in the duodenal epithelium or in the superficial rectal epithelium. In two cases (5% of the positive biopsies), they were found in rectal glands: the HIV-infected cells could be either epithelial cells or immune cells. This study confirms that the gut can be a target organ for HIV and that HIV is mainly carried by gut immune cells. The phenotypic study of lymphoid populations and macrophages in the gut mucosa of AIDS patients showed an inverse CD4/CD8 ratio in the lamina propria, compared with normal controls. This was independent of the presence of HIV proteins and is probably responsible for the appearance of opportunistic infections in the mucosa. An increase in activated macrophages was also noted in the mucosa of AIDS patients.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Same peculiar subset of HML1 + lymphocytes present within normal intestinal epithelium is associated with tumoral epithelium of gastrointestinal carcinomas.

The present study shows that the distribution of T lymphocytes in gastrointestinal carcinomas and their metastases mimic the distribution of T lymphocytes in normal intestine. The composition of the peritumoral reaction resembled that of normal lamina propria with a predominance of CD3 + CD4 + T cells. In contrast, lymphocytes located between carcinomatous cells showed phenotypical features similar to those of intraepithelial lymphocytes (IEL) in normal intestine; in particu(abstractlar they expressed the antigen defined by HML-1, a monoclonal antibody raised against normal human intestinal IEL which reveals 95% IEL but very few cells in lymphoid (abstractorgans and blood. As normal intestinal IEL, the majority of intratumoral lymphocytes had the CD3+ CD8+ phenotype. A panel of monoclonal antibodies and double immunostaining techniques permitted a better characterisation of minor subsets of IEL. Two subsets of HML1 + CD3 + CD4- CD8- and of HML1+ CD3- cells, representing 2% and 3% of normal intestinal IEL respectively, did not significantly increase in carcinomatous epithelium. In contrast, in carcinomatous epithelium, but not in normal intestinal epithelium, we observed the appearance of a few lymphocytes displaying the phenotype of activated T cells (CD25+) or of natural killer cells (NKHI+) or of suppressor cells (CD11+). Such cells may participate in antitumoral defence. Although a similar population of HML1+ lymphocytes is associated with normal and carcinomatous intestinal epithelium, some interactions between lymphocytes and epithelial cells may not be maintained in tumoral epithelium. It has previously been shown that HLA-DR expression by enterocytes is modulated by intraepithelial lymphocytes. In our study, no correlation could be shown between the degree of lymphocytic infiltration and the expression of HLA-DR antigens on carcinomatous cells.

Adenocarcinoma↗

PubMedDate not supplied

[RNA isolation and purification methods].

Recent advances in human, bacterial and viral genome projects and the development of quantitative real-time reverse transcription-polymerase chain reaction methods offer the possibility of analysing a large number of gene transcripts. These molecular developments represent an important advancein the field of genetics, cancer, virology, bacteriology and hematology. A limiting step remains the isolation of high quality mRNA purified from biological samples. This review describes the different methods used to isolate mRNA from biological samples and to verify RNA integrity and gives precise details about RNA storage conditions.

Blotting, Northern↗