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Biomedical subjects

H Tesch

Publications and source records attributed to H Tesch.

At least 127 records · Page 7Linked to original sources
PubMed1990

Analysis of bcr rearrangements in primary (essential) thrombocythaemia.

A clinical and molecular study was performed on 10 patients with the presumptive diagnosis of primary thrombocythaemia (PTH). In all cases conspicuous megakaryocytic proliferation in bone marrow smears was detected in the absence of the Philadelphia chromosome (Ph1), elevated red blood cell mass and evidence for a reactive cause of the thrombocytosis. We analyzed whether rearrangements of the bcr gene occurred in untreated patients. Bcr rearrangements were detected in the bone marrow cells but not in peripheral blood bells of one patient, indicating that this case might be related at the molecular level with Philadelphia chromosome negative CML, in which bcr rearrangements could be demonstrated.

Adult↗
PubMed1990

Cellular oncogenes in human teratocarcinoma cell lines.

We have analysed, by Northern blots, the expression of 14 cellular oncogenes in nine cell lines established from human teratocarcinomas. All lines expressed considerable amounts of p53, c-Ki-ras2, c-Ha-ras1, c-raf1, N-myc, and c-fos. Low level expression of c-myc was detected in some lines. Southern blot experiments revealed no amplification or rearrangement of the c-Ki-ras2, N-myc or c-fos genes. Using a rapid dot-blot screening procedure, based on a combination of in-vitro amplification of ras-specific sequences and oligonucleotide hybridization, we could detect no activation of Ha-ras or Ki-ras or any unexpressed N-ras sequences secondary to a point mutation at codons 12, 13, or 61.

Blotting, Northern↗
PubMed1990

Analysis of immunoglobulin, T cell receptor and bcr rearrangements in human malignant lymphoma and Hodgkin's disease.

Rearrangements of immunoglobulin and T cell receptor (TCR) genes have been demonstrated in malignant lymphoid tumors of B and T cell origin. In Philadelphia chromosome-positive chronic myeloid leukemia and acute lymphocytic leukemia cells the bcr and c-abl genes are reorganized and transcripts composed of both genes are expressed. We analyzed the organization of bcr, immunoglobulin and TCR genes in malignant lymphomas. Our data show that in all B cell lymphomas analyzed the JH genes and in some cases also the J kappa genes were rearranged. In a Burkitt lymphoma and in a Kil lymphoma distinct rearranged TCR gamma fragments were detected, in a second Burkitt lymphoma two rearranged TCR beta gene fragments occurred together with a rearranged JH gene fragment. In two T cell lymphomas rearranged TCR beta genes were observed; one of these lymphomas also carried rearranged TCR gamma and JH genes. In Hodgkin's disease in 3 out of 7 cases rearranged immunoglobulin genes were detected. In 1 case, which was diagnosed as a follicular hyperplasia, rearranged JH and TCR gamma fragments appeared. In none of the analyzed lymphomas could bcr rearrangements be observed.

Gene Rearrangement↗
PubMed1989

CD20 positive human B lymphocytes separated with the magnetic cell sorter (MACS) can be induced to proliferation and antibody secretion in vitro.

A method is described for the efficient purification of human B lymphocytes from peripheral blood by magnetic separation. Biotinylated, superparamagnetic particles were coupled to target cells by fluorescein isothiocyanate conjugated avidin and biotinylated monoclonal antibodies directed against cell surface antigens. This combination permitted flow cytometric control of the magnetic separation. Ficoll-Paque-separated peripheral blood mononuclear cells were first eliminated from monocytes by leucine-methyl ester treatment. B cells were enriched to 97% after magnetic depletion of CD3-positive T cells and magnetic enrichment of CD20-positive B cells. The separated B cells could be induced to proliferation and antibody production by various in vitro stimuli.

Antibody-Producing Cells↗
PubMed1989

Translocation of c-abl oncogene and PDGFB (c-sis) gene in a case of CML with 46,XY, t(22;22).

In a case of CML with a variant Philadelphia translocation (Ph1 or Ph) t(22;22) (q11;q13) in bone marrow cells and unstimulated peripheral blood cells, no cytogenetically detectable involvement of chromosome 9 was observed. Southern blot experiments using probes specific for bcr and c-sis however revealed rearrangement of the bcr, but not of PDGFB (c-sis) gene. Northern blot analysis of bone marrow RNA showed a very weak signal with the c-sis probe, while in a lymph-node biopsy PDGFB m-RNA could not be detected. Chromosomal in situ hybridization gave evidence for translocation of c-abl from chromosome 9 to Ph and of PDGFB from chromosome 22 to chromosome 9, as the result of a threefold translocation t(9;22;22).

Bone Marrow↗
PubMed1989

Analysis of immunoglobulin and T cell receptor gene rearrangements in the thymus of myasthenia gravis patients.

The thymus is an important site of sensitization of autoreactive B and T lymphocytes in myasthenia gravis (MG). We have investigated clonal diversity of B or T cells in the thymus of patients with MG by Southern blot experiments using probes specific for immunoglobulin heavy (IgH) and light chain (IgL) genes and for T cell receptor (TCR) beta- and gamma-chain genes. This method allows to detect individual clones of B or T cells if they represent at least 1% of the total cell population. We investigated thymus glands from 14 patients who underwent thymectomy. Single rearranged fragments could be demonstrated with a TCR gamma-specific probe in DNAs from both normal donors and MG patients. TCR beta gene rearrangements occurred mainly in the C beta 1 region. However, single rearranged bands could not be detected with either TCR beta, JH or with J kappa specific probes. Thus any single autoimmune B and T cell clone present in the myasthenic thymus represents presumably less than 1% of all thymocytes.

Blotting, Southern↗
PubMed1989

Increased levels of IgG subclasses specific for Pseudomonas aeruginosa exoenzyme and polysaccharide antigens in chronically infected patients with cystic fibrosis.

IgG subclass levels to Pseudomonas aeruginosa alginate, alkaline proteinase, elastase and exotoxin A in sera of healthy adults, non-infected and infected cystic fibrosis patients were investigated by enzyme linked immunosorbent assay. Whereas healthy adults and non-infected cystic fibrosis patients revealed mostly negative IgG subclass levels to the four antigens, infected cystic fibrosis patients had significantly elevated IgG1, IgG2, IgG3 and IgG4 levels to both the protein antigens as well as the polysaccharide antigen. The study does not support previous findings of an impaired natural IgG2 response to polysaccharide antigen. The study does not support previous findings of an impaired natural IgG2 response to polysaccharide in chronically infected cystic fibrosis patients.

ADP Ribose Transferases↗
PubMed1988

[Oncogenes in squamous epithelial cancers in the area of the head and neck].

Proto-oncogenes are a part of the genetic code of each human cell. Physiologically they code special enzymes, membrane receptors and growth factors which are necessary for cell growth and function. Alterations in these genes like amplification, rearrangements, mutations or chromosomal translocation appeared to be implicated in the induction of neoplasms. So these genes were called "oncogenes". Recent work has shown that increased expression of the c-myc oncogene in squamous cell carcinoma (SCC) of the head and neck is related to advanced SCC stages (TNM). We examined more than fourty human SCC of the head and neck with Southern blot analysis for c-myc amplification and rearrangement. Our preliminary results indicate that c-myc amplification is correlated with advanced tumour stages and highly aggressive tumour behaviour. Patients with c-myc amplification (15%) all show regional lymph node metastasis. No rearrangement has been seen. Further studies must confirm our results and examine whether c-myc amplification is correlated with the biological characteristics of SCC of the head and neck.

Carcinoma, Squamous Cell↗
PubMed1987

Phenotype versus immunoglobulin and T-cell receptor genotype of Hodgkin-derived cell lines: activation of immature lymphoid cells in Hodgkin's disease.

Three Hodgkin-derived cell lines (L428, L540, and CO) were studied for rearrangements and expression of immunoglobulin and T-cell receptor genes, and their genotype was compared to the phenotype. As far as the genotype is concerned, all 3 cell lines have characteristics of lymphoid cells; L428 of B, and L540 and CO of T-cell origin. L428 cells have one Ig heavy chain allele rearranged to C gamma and transcribed into RNA, while the second is deleted. Furthermore, L428 cells show an unusual immunoglobulin kappa light chain gene rearrangement involving deletion of the kappa constant gene in one allele, while the remaining kappa and lambda loci are in germline configuration. L540 and CO have, in contrast to L428 cells, the immunoglobulin genes in germline and T-cell receptor genes rearranged. The T-cell receptor beta and gamma genes are rearranged in both L540 and CO, whereas a rearrangement in the alpha locus was detected in L540 cells only. RNA of the size of functional beta chain transcripts was found in CO cells and of the size of functional alpha chain transcripts in L540 cells. All 3 cell lines are classified as immature lymphoid cells with respect to the limited expression of B- and T-cell antigens, respectively, and to the incomplete expression of their antigen receptor. The immaturity of lymphoid differentiation contrasts with the expression of activation antigens, i.e. Ki-1, Ki-24, HLA-DR, and IL-2 receptor. The immaturity of the cells excludes the possibility that the cells were activated along the physiological pathway, i.e. by interaction of the cell with antigen. The results obtained on the cell lines are in accordance with in vivo studies and suggest that Hodgkin and Sternberg-Reed cells are immature lymphoid cells which are activated by a still unknown mechanism.

Cell Line↗
PubMed1986

Lymphokines regulate immunoglobulin isotype expression in an antigen-specific immune response.

The control of immunoglobulin class switching appears to involve T cell-derived lymphokines. Such lymphokines have been shown to affect isotype expression in polyclonally activated B cells. We show in this paper that the same lymphokines similarly control isotype expression in an antigen-specific response acting in concert with a "T cell independent" antigen. In this situation, B cell growth factor II (BCGF II) enhances the production of antigen-specific IgM antibodies, whereas the production of antigen-specific IgG1 antibodies is only observed in the presence of B cell differentiation factor gamma (BCDF gamma). These results suggest that these lymphokines (and perhaps additional ones) are involved in the control of isotype expression in antigen-specific responses.

Animals↗
PubMed1985

Signal requirements for growth and differentiation of activated murine B lymphocytes.

Mouse B lymphocytes were stimulated at high cell concentrations with goat anti-IgM antibodies, which leads to the induction of B cell proliferation without the addition of any growth factors. After 48 hr, blast cells were purified and cultured at low cell concentrations. Proliferation and differentiation of purified B lymphocyte blasts is then dependent on the addition of either mitogens (e.g., LPS) or certain lymphokines derived from activated T cells or macrophages. One such lymphokine was isolated from supernatants of various activated T cells and characterized by gel filtration as a material with an apparent m.w. of 40,000 to 50,000, similar to BCGF II. It supports the proliferation of the B cell blasts and induces their differentiation into plaque-forming cells. Lymphokines such as BCGF I, interleukin 2, and BCDF gamma could neither maintain growth nor induce differentiation of B lymphocytes preactivated by goat anti-IgM.

Animals↗