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Biomedical subjects

A Moreau

Publications and source records attributed to A Moreau.

12 recordsLinked to original sources
PubMed1992

Cloning and expression in Escherichia coli of a xylanase-encoding gene from the yeast Cryptococcus albidus.

In the yeast, Cryptococcus albidus, a comparison between the sequence of the xylanase (XLN)-encoding chromosomal gene (XLN) and the cDNA sequence reveals the presence of seven introns, ranging in length from 51 to 69 bp. One of their 5' splice site sequences is similar to the consensus sequence for yeast, while the other six resemble the consensus sequence for higher eukaryotes. Their 3' end splice site sequences are representative of the conserved sequence found in eukaryotes. Their putative branching point sequences are different from the well-known conserved sequence, 5'-TACTAAC, observed in yeast, but again resemble the mammalian one. The cDNA encoding XLN is expressed by Escherichia coli, under the control of the lacZ promoter. The gene product remains inside the cell and has a molecular size of 40 kDa, which matches the size of the nonglycosylated protein. When compared to the glycosylated enzyme, the nonglycosylated XLN from E. coli shows twofold less affinity for substrate and its Vmax is 100-fold lower. Moreover, the nonglycosylated XLN only acts on large xylan polymers and very slightly on xylohexaose.

Base Sequence↗
PubMed1992

Secretion of a Cryptococcus albidus xylanase in Saccharomyces cerevisiae.

The xylanase(XLN)-encoding gene(XLN) of Cryptococcus albidus and its cDNA were each inserted into the vector, pVT100, for expression in Saccharomyces cerevisiae. Expression was under the control of either their own promoter or the gene encoding alcohol dehydrogenase (ADH1) promoter. Yeast transformed with plasmids containing the cDNA of the structural XLN gene and the XLN promoter produced active extracellular XLN when grown with galactose as carbon source. However, with glucose as carbon source, XLN was repressed. Using the ADH1 promoter, which is stimulated by glucose, XLN was secreted into the culture medium. In both cases, the secreted 48-kDa enzyme corresponded to the native XLN produced by C. albidus. With the plasmid bearing the genomic XLN gene, there was transcription, but the seven introns interrupting XLN were not spliced out by S. cerevisiae and no enzyme was produced.

Alcohol Dehydrogenase↗
PubMed1992

Drug-induced prolonged cholestasis in adults: a histological semiquantitative study demonstrating progressive ductopenia.

Drug-induced acute hepatitis may be followed by prolonged cholestasis despite the withdrawal of the drug. Eight patients suffering from prolonged cholestasis caused by several drugs were investigated with sequential liver biopsies. At the early stage, lesions of acute cholangitis were observed in most patients; at the chronic phase, ductopenia, defined by the absence of interlobular bile ducts in at least 50% of small portal tracts, was demonstrated in all patients. Ductopenia might be the consequence of acute cholangitis; the degree of ductopenia and the chronicity of the disease might be directly related to the severity of the early acute damage of bile ducts. Consequently, in patients with severe cholestasis related to drugs, research of early morphological signs of acute cholangitis and then of ductopenia seems to be important.

Adult↗
PubMed1992

Primary Epstein-Barr virus infection with clonal T-cell lymphoproliferation.

A case of fatal Epstein-Barr virus infection in a previously healthy girl who was first found to have severe infectious mononucleosis with spontaneous recovery is reported. Because an abnormal immune response to the virus persisted, the disease relapsed, manifesting in cutaneous and pulmonary lesions associated with hemophagocytic syndrome responsible for death. Pathologic findings were characterized by polymorphous atypical lymphoid infiltrate, prominent necrosis, and histiocytic hyperplasia. Lymphoid cells displayed CD8 phenotype and clonal T-cell receptor gene rearrangement. Viral genome was detected in lesions by Southern blot and located in nuclei of lymphoid cells by in situ hybridization. Pathologic findings suggested fatal infectious mononucleosis; however, phenotype and genotype favored a malignant diagnosis. Clonality was demonstrated to have arisen during primary infection. Virologic examination indicated that Epstein-Barr virus was a causative agent. Such a process belongs to the recently recognized spectrum of Epstein-Barr virus-related T-cell lymphoproliferative disorders that might overlap fatal infectious mononucleosis in patients who are especially vulnerable to the virus.

Adolescent↗
PubMed1992

A novel shuttle vector for Streptomyces spp. and Escherichia coli as a tool in site-directed mutagenesis.

This paper describes the construction and utilization of a novel shuttle vector for Streptomyces spp. and Escherichia coli as a useful vector in site-directed mutagenesis. The shuttle vector pIAFS20 (6.7 kb) has the following features: a replicon for Streptomyces spp., isolated from plasmid pIJ702; the thiostrepton-resistance gene as a selective marker in Streptomyces; the ColE1 origin, allowing replication in E. coli; and the ampicillin-resistance gene as a selective marker in E. coli. Vector pIAFS20 also contains the phage f1 intergenic region, which permits production of single-stranded DNA in E. coli after superinfection with helper phage M13K07. Moreover, the lac promoter is located in front of the multiple cloning sites cassette, allowing eventual expression of the cloned genes in E. coli. After mutagenesis and screening of the mutants in E. coli, the plasmids can be readily used to transform Streptomyces spp. As a demonstration, a 3.2-kb DNA fragment containing the gene encoding the xylanase A from Streptomyces lividans 1326 was inserted into pIAFS20, and the promoter region of this gene served as a target for site-directed mutagenesis. The two deletions reported here confirm the efficiency of this new vector as a tool in mutagenesis.

Base Sequence↗
PubMed1992

[Nephroblastomatosis and Wilms' tumor. Apropos of a case].

This case report illustrates the different anatomopathologic patterns and evolutive potentials of perilobar nephroblastomatosis described by Beckwith. The latter differs from those of an intralobar nephroblastomatosis. The evolutive possibilities of nephroblastomatosis underline the importance of imaging technology in the diagnosis and control of such lesions, as well as the role of chemotherapy and above all the caution required in the indications for surgery.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Immunohistochemical detection of cells positive for colony-stimulating factor 1 in lymph nodes from reactive lymphadenitis, and Hodgkin's disease.

Colony-stimulating factor 1 (CSF-1) is a cytokine involved in hematopoiesis and perhaps more importantly in the early stages of immunological defense mechanisms. Although numerous studies of in vitro CSF-1-producing cells have been published, in vivo data is totally lacking. According, we performed immunohistochemical detection of CSF-1-positive cells on frozen sections of reactive lymphadenitis (three cases) and Hodgkin's disease (13 cases) lymph node biopsies, using as antibody a highly specific polyclonal rabbit antiserum prepared in our laboratory. Endothelial cells from high endothelial venules and most fibroblasts were positive in all cases (reactive lymphadenitis and Hodgkin's samples), and most lymphocytes in interfollicular T cell areas showed faint granular positivity in reactive lymphadenitis lymph nodes. Hodgkin and Reed-Sternberg cells were positive in all cases tested, although staining intensity was highly variable and the percentage of positive cells differed from case to case. These data from in vivo biopsies confirm previous results for in vitro CSF-1 production by endothelial cells, fibroblasts, T lymphocytes, and Hodgkin cell lines. They are consistent with the role of this cytokine in immune response and raise the question of its significance in Hodgkin's disease.

Hodgkin Disease↗
PubMed1991

Assignment by in situ hybridization of a fibroblast growth factor receptor gene to human chromosome band 10q26.

A 2.3-kb cDNA probe for the human bek fibroblast growth factor receptor was used to determine the chromosomal localization of the corresponding gene by in situ hybridization. The results show that this gene, a form of which is amplified in some poorly differentiated stomach cancers, is localized on chromosome region 10q26. The two previously identified fibroblast growth factor receptor genes are thus not on the same chromosome, as the related flg ("fms-like gene") fibroblast growth factor receptor gene has previously been mapped to human chromosome region 8p12.

Autoradiography↗
PubMed1991

Progress in outgrowth culture from rabbit tracheal explants: balance between proliferation and maintenance of differentiated state in epithelial cells.

Primary cultures of rabbit tracheal cells were obtained as outgrowths from explants of tracheal mucosa. A 30% collagen substratum containing serum and minimal essential medium was required for obtaining an outgrowth of epithelial cells keeping their differentiated characteristics. The tracheal epithelial cells obtained near the explant in the first days of culture presented morphologic similarities with normal tracheal epithelium. Cultures contained basal cells and epithelial polarized cells that exhibited apical tight junctions and desmosomes. Ciliated cells stayed functional during all time culture. Their number slightly increased at the beginning of the culture and then stayed constant when the total number of cells increased. Development of the outgrowth was rapid and significant inasmuch as the outgrowth surface reached 30 times that of the explant after less than 8 days. This was linked to cellular proliferation, as demonstrated by the incorporation of bromodeoxyuridine (BrdU) in phase-S nuclei and the revelation of BrdU using an immunofluorescence technique. The epithelial nature of the outgrowth cells and the absence of contamination with fibroblasts were established by positive staining with anti-keratin antibody and by negative staining with anti-vimentin antibody, respectively.

Animals↗
PubMedDate not supplied

[A kibbutz group].

Kibbouts-group: three therapeutic or growth factors together: manual work, community life and group technics (group dynamic, Gestalt, psychodrama, bio-energetic) during two weeks. The work of growing and therapy is becoming more concrete and facilitated by the absence of difference between members and leader who share the work and the community life. Important and rapid changes are frequent: a particular attention is given to the "unmedicalisation" of symptoms (fatigue) and to the "unpsychiatrisation" of conflicts. A sample and authentical life style, together with a high degree of communication, favor the desinhibition of attitudes, the clarification of conflicts and the reenforcement of the personality.

Belgium↗
PubMedDate not supplied

Intralymphnode injection of human monocyte macrophage colony stimulating factor (CSF-1) as a method of obtaining high titer anti-CSF-1 antibodies.

We describe a rabbit intralymphnode immunization technique for obtaining a high titer antihuman CSF-1 antiserum with small amounts of antigen. This procedure provided a rapid (42 days after primo-injection), stable maximum immune response with a high titer antiserum precipitating 30% of 125I CSF-1 at a 1:25.000 dilution. The specificity of the immune serum was assessed by competitive binding experiments in RIA and neutralization of the CSF-1 biological activity in culture. The antiserum was also tested for its ability to detect CSF-1 in Western blotting, immunocytochemistry and immunohisto-chemistry. The results show that the immune serum specifically recognizes the biological active domain of human CSF-1 molecules from different origins and only detects dimeric forms. The potential uses of this anti CSF-1 antiserum are discussed.

Animals↗