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T Pietsch

Publications and source records attributed to T Pietsch.

10 recordsLinked to original sources
PubMed1992

Effects of human stem cell factor (c-kit ligand) on proliferation of myeloid leukemia cells: heterogeneity in response and synergy with other hematopoietic growth factors.

A novel hematopoietic growth factor, the stem cell factor (SCF), for primitive hematopoietic progenitor cells has recently been purified and its gene has been cloned. In this study we tested the mitogenic activity of recombinant human SCF on myeloid leukemia cells as well as the expression of its receptor. We have investigated the proliferation of 31 myeloid leukemia cell lines as well as fresh myeloid leukemic blasts from 17 patients in a 72-hour 3H-thymidine uptake assay in the presence of various concentrations of recombinant human (rh) SCF alone or in combination with saturating concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, M-CSF, interleukin-3 (IL-3), or erythropoietin (EPO). Only five of 31 lines, but fresh leukemic blasts from 12 of 17 patients with acute myeloid leukemia (AML), significantly responded to SCF. The responding cell lines were of the acute promyelocytic, chronic myeloid, megakaryoblastic, and erythroleukemia origin, the responding blast preparations of all French-American-British subtypes. Synergistic activities of SCF were found with G-CSF, GM-CSF, EPO, and IL-3. To determine the SCF binding sites on leukemic cells, we used 125I-radiolabeled SCF in Scatchard analysis and cross-linking studies. The leukemic cell lines responding to SCF expressed from 2,300 up to 29,000 binding sites per cell. The SCF receptor expression was downregulated in vitro by the presence of its ligand. Cross-linking studies demonstrated a 150-Kd SCF receptor on the surface of all responding myeloid leukemias. This study suggests that SCF may be an important factor for the growth of myeloid leukemia cells, either as a direct stimulus or as a synergistic factor for other cytokines. Furthermore, using polymerase chain reaction analysis of total RNA from the myeloid leukemia lines, we found expression of SCF-mRNA in 17 of 30 lines, suggesting autocrine mechanisms in the growth of a subgroup of leukemic cells by coexpression of SCF and its receptor.

Cell Division↗
PubMed1992

Expression of receptors for granulocyte colony-stimulating factor on neutrophils from patients with severe congenital neutropenia and cyclic neutropenia.

We studied granulocyte colony-stimulating factor (G-CSF) binding sites on neutrophils from patients with severe congenital neutropenia (SCN; Kostmann-syndrome) and cyclic neutropenia (CN) during treatment with recombinant human (rh) G-CSF. G-CSF receptor expression was measured by scatchard analysis. Neutrophils from six healthy controls expressed between 480 and 1,210 binding sites per cell, whereas neutrophils from five SCN patients expressed increased numbers of G-CSF binding sites ranging between 2,100 and 3,900 per cell. Neutrophils from four patients with CN expressed 350 to 1,600 binding sites per cell. The affinity of rhG-CSF to its receptor was similar in patients and controls. These data suggest that SCN patients and CN patients are not defective in G-CSF receptor expression as judged by the numbers of G-CSF binding sites and binding affinity; however, we cannot exclude defects in parts of the G-CSF receptor that may be involved in the signal transduction pathway.

Adolescent↗
PubMed1992

Dolastatin 10 and dolastatin 15: effects of two natural peptides on growth and differentiation of leukemia cells.

The effects of two natural peptides, dolastatin 10 and dolastatin 15, on growth and differentiation of hematopoietic cells were studied using freshly explanted leukemia cells and continuous leukemia cell lines. The proliferation of several myeloid cell lines and of growth-factor-stimulated peripheral blood cells from patients with acute myeloid leukemia (AML) was efficiently inhibited by the two agents at concentrations between 1 and 0.01 nM. Growth inhibition was dose-dependent and reversible. Neither of the dolastatins exhibited significant cytotoxicity on dividing cells, nor did they interfere with the viability of resting cells. The 12-O-tetradecanoylphorbol 13-acetate or bryostatin I induced differentiation of AML cells was not affected by the dolastatins. Short-term exposure to the phorbol ester conferred reduced sensitivity of the cell line HL-60 to the antiproliferative effect of the drugs. Our data suggest that the dolastatins alone or in combination with other drugs could exert a role in the treatment of human myeloid leukemia.

Antineoplastic Agents↗
PubMed1991

Increased serum levels of granulocyte colony-stimulating factor in patients with severe congenital neutropenia.

Severe congenital neutropenia (SCN), also known as Kostmann Syndrome, is characterized by a maturation arrest of myelopoiesis at the level of promyelocytes with absence of neutrophils in bone marrow (BM) and blood. Hypotheses of the pathophysiology of SCN include (1) defective production of granulocyte colony-stimulating factor (G-CSF), and/or (2) defective response to G-CSF. To exclude defective G-CSF production we tested sera from patients with SCN for the presence of G-CSF using Western blot analysis and NFS-60 proliferation assay. Using these assays we were able to detect increased G-CSF serum levels in SCN patients (150 to 910 pg/mL) as compared with normal controls (between undetectable and 100 pg/mL). These results suggest that patients with SCN have no defect in G-CSF production but a defective response of neutrophil precursors to endogenous G-CSF.

Adult↗
PubMed1991

Blood mononuclear cells from patients with severe congenital neutropenia are capable of producing granulocyte colony-stimulating factor.

Severe congenital neutropenia (SCN) is a disorder of myelopoiesis characterized by severe neutropenia or absence of blood neutrophils secondary to a maturational arrest at the level of promyelocytes. We examined peripheral blood mononuclear cells (PBMC) of SCN patients who demonstrated normalization of their blood neutrophil counts in a phase II clinical study with recombinant human granulocyte colony-stimulating factor (rhG-CSF). When stimulated in vitro with bacterial lipopolysaccharides (LPS), PBMC of those SCN patients produced G-CSF activity, as judged by proliferation induction of the murine leukemia cell line, NFS-60. Western and Northern blot analysis showed G-CSF protein and G-CSF-mRNA indistinguishable in size from those of normal controls. We conclude that PBMC of the SCN patients tested are capable of synthesizing and secreting biologically active G-CSF in vitro.

Adult↗
PubMed1989

Monoclonal antibody T-199 directed against human medulloblastoma: characterization of a new antigenic system expressed on neuroectodermal tumors and natural killer cells.

A monoclonal antibody (mAb) (T-199) of IgG1 isotype was raised against medulloblastoma by immunizations of mice with the medulloblastoma cell line TE-671. Studies of the specificity of mAb T-199 on cell lines as well as fresh frozen sections of normal and malignant tissues revealed the antigen in high amounts on the cell surface of neuroectodermally derived tumors such as medulloblastoma, neuroblastoma, retinoblastoma, and astrocytoma. Some melanomas and a subgroup of rhabdomyosarcomas also expressed the antigen. In contrast, mesenchymal tumors, osteosarcomas, and Ewing's sarcomas did not bear the T-199 antigen. Reactivity of T-199 with normal tissues has not been found with few exceptions; in certain areas of the brain, especially in the cerebellum and part of the hypothalamus, in the adrenal glands, and in the pancreatic islet cells small amounts of antigen were detectable. Natural killer cells could also be demonstrated to express the T-199 antigen similar to the NKH-1 antigen. However, despite some striking similarities, the antigens or antigen epitopes recognized by mAbs T-199 and NKH-1 are not identical. Therefore, mAb T-199 seems to detect a unique differentiation antigen on neuroectodermal tumors, coexpressed in low amounts on normal neuroectodermally derived cells and natural killer cells. The pattern of reactivity and the biochemical properties of the T-199 antigen are different from other cell surface markers for neuroectodermal cells coexpressed on natural killer cells or T-cells (HNK-1, NKH-1, or Thy-1). Biochemical analysis of the T-199 antigen showed that it is a heat-labile protein.

Antibodies, Monoclonal↗
PubMed1989

Embryonic neural cell adhesion molecules on human natural killer cells.

The neural cell adhesion molecules (NCAM) are surface glycoproteins that were first described in brain tissue. NCAM mediate adhesion in a variety of cell-cell interactions. In the present study we show that the so-called "embryonic" NCAM, i.e., the highly polysialylated forms of these proteins, are expressed on natural killer cells and some CD3+ cells in man. Homotypic binding of NCAM, believed to be of importance for cell-cell adhesion in neural tissues, appears not to be essential for NK cell-mediated killing. Yet, NCAM might be involved in NK cell migration, homing or related functions.

Antibodies, Monoclonal↗
PubMedDate not supplied

Medulloblastoma cells constitutively produce granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor (G-CSF) was previously shown to be produced constitutively by malignant epithelial cells and by monocytes/macrophages, fibroblasts and endothelial cells following stimulation. In this study we investigated the ability of medulloblastoma cells, representing malignant embryonal neuroectodermal cells, to produce G-CSF. Conditioned medium was freshly prepared from unstimulated explanted tumor tissue from two patients with medulloblastoma as well as from the medulloblastoma cell lines TE-671 and DAOY, and as controls normal glial cells. Following 72 hours of culture at a density of 5 x 10(5) cells/ml in RPMI 1640 with 10% FCS, the supernatants were harvested and tested for the presence of G-CSF in (1) the CFU-GM asay, (2) proliferation assay using the G-CSF dependent cell line NFS-60, and (3) Western blot analysis using an anti-G-CSF monoclonal antibody. Biological active and immunological detectable G-CSF was secreted by the medulloblastoma cell line DAOY and by one of the explanted tumor biopsies. The cell line TE-671 as well as normal glial cells did not produce G-CSF under identical culture conditions. We conclude that in addition to previously described sources of G-CSF, neuroectodermally derived medulloblastoma cells are also able to produce G-CSF constitutively. The G-CSF production was increased after stimulation with IL-1 alpha or TNF alpha. The role of G-CSF in neuroectodermal tissues remains to be further investigated.

Bone Marrow↗
PubMedDate not supplied

Characterization of a continuous cell line (MHH-NB-11) derived from advanced neuroblastoma.

A continuous cell line was established from an explanted tumor biopsy obtained from a patient with advanced neuroblastoma, which showed no response to chemotherapy. This cell line MHH-NB-11 retained most properties of the original immature tumor, even after xenotransplantation into nude mice. The cell line consisted of small dense cells with scant cytoplasm and thin; long processes and expressed neuron-specific enolase and synaptophysin, but neither GFAP nor S-100 protein. Karyotyping showed karyograms with 49 to 54 chromosomes, with a modal at 52. Most cells had trisomy 2,7,8,20, but only few structural aberrations were observed. Two of four chromosomes 1 showed a rearrangement of the terminal 1p segment, and all cells had a long HSR on the long arm of one of the chromosomes 13. This region hybridized in situ with the N-myc probe pNB-1. N-myc was amplified 20-fold in this neuroblastoma cell line as determined in Southern blot analysis. This cell line should be a useful tool in vitro or as a xenograft model for neuroblastoma research.

Animals↗