Publications by authors named "Tanja Heller"

Mutations in Patched (PTCH) have been associated with tumors characteristic both for children [medulloblastoma (MB) and rhabdomyosarcoma (RMS)] and for elderly [basal cell carcinoma (BCC)]. The determinants of the variability in tumor onset and histology are unknown. We investigated the effects of the time-point and dosage of Ptch inactivation on tumor spectrum using conditional Ptch-knockout mice.

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The antiproliferative immunosuppressive drug mycophenolic acid (MPA) is an uncompetitive inhibitor of inosine monophosphate dehydrogenase, a key enzyme in de novo synthesis of purine nucleotides. The latter are not only required for synthesis of DNA and RNA but also are essential for the regulation of numerous cellular signaling pathways modulated by guanine nucleotide binding proteins (G proteins). We undertook an analysis of the influence of MPA on protein expression in a T-lymphoblast cell line (CCRF-CEM), which displays concentration-dependent inhibition of proliferation by MPA to obtain insight into the influence of MPA on the cellular proteome.

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The aim of the present study was to investigate whether the acyl glucuronide of mycophenolic acid (AcMPAG) directly affects gene expression independent of guanosine (G) depletion. Human native mononuclear cells from healthy volunteers were studied. A concentration of 100 micromol/L (50 mg/L) AcMPAG, which provided effective inhibition of cell proliferation according to dose-response curves, was selected for gene expression analysis on microarray, verified by quantitative real-time polymerase chain reaction on the LightCycler.

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Objective: To evaluate the Abbott CELL-DYN Sapphire cytometer for cerebrospinal fluid (CSF) cell count and differentiation.

Methods: One hundred three analyses of CSF cells by the CELL-DYN Sapphire were compared with routine cell count and microscopic differentiation and correlation coefficients calculated.

Results: The total cell count of both methods correlated well.

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Background: Diarrhea and anemia are side effects of mycophenolic acid (MPA), but underlying mechanisms are not fully understood. Gene expression of major-alpha-hemoglobin and catalase was suppressed in livers of mycophenolate mofetil (MMF)-treated rats, suggesting MPA attenuates cellular defense against reactive oxygen species (ROS). We investigated whether the antioxidant idebenone might alleviate MPA-related side effects.

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A first step in hematopoiesis is the specification of the lymphoid and myeloid lineages from multipotent progenitor cells in the bone marrow. Using a conditional ablation strategy in adult mice, we show that this differentiation step requires Patched (Ptch), the cell surface-bound receptor for Hedgehog (Hh). In the absence of Ptch, the development of T- and B-lymphoid lineages is blocked at the level of the common lymphoid progenitor in the bone marrow.

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Methods for Cytochrome P450-2D6 (CYP2D6) genotyping are often time-consuming and laborious, which can restrict their use in pretherapeutic screening programs. Gene chip technology could overcome this problem. The aim of this study was to evaluate CYP2D6 genotyping by a new improved gene chip compared to a PCR-RFLP method.

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Immune complex (IC)-induced inflammation is integral to the pathogenesis of several autoimmune diseases. ICs activate the complement system and interact with IgG FcgammaR. In this study, we demonstrate that activation of the complement system, specifically generation of C5a, initiates the neutrophilic inflammation in IC peritonitis.

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