PubMed Health⌕ Search

Biomedical subjects

F Herrmann

Publications and source records attributed to F Herrmann.

At least 109 records · Page 6Linked to original sources
PubMed1994

Regulation of MCP-1/JE gene expression during monocytic differentiation.

We examined the expression of the MCP-1/JE gene in freshly prepared human monocytes and again after either in vitro or in vivo maturation of these cells. We show that previously unstimulated blood monocytes of healthy individuals prepared by adherence procedures display high levels of MCP-1/JE mRNA and protein. Monocytes that were not previously exposed to activational plastic surfaces but were separated from other blood cells by counter-flow centrifugal elutriation expressed severalfold lower MCP-1/JE transcript and protein levels. Treatment of these cells with endotoxin was associated with the down-regulation of MCP-1/JE mRNA and protein levels. In contrast, exposure to IFN-gamma resulted in increased MCP-1/JE gene expression. During the process of in vitro maturation of monocytes into macrophages, a gradual decrease of MCP-1/JE mRNA and protein expression was noted. Both mature (day 8) blood monocyte-derived culture macrophages and peritoneal macrophages completely failed to express the MCP-1/JE gene, which could be restored after exposure to IFN-gamma and cross-linking of macrophage Fc gamma R with murine solid phase IgG2a mAbs; however, endotoxin failed to induce MCP-1/JE expression in these cells.

Blotting, Northern↗
PubMed1994

[Trends in the prescription of cardiovascular drugs in a geriatric hospital].

Analysis of drug prescriptions in a geriatric hospital between 1988 and 1993 shows a high prescription rate for cardiovascular drugs (50 to 60%). Moreover, multiple prescriptions are more frequent for patients receiving cardiovascular drugs. The most widely prescribed drugs are coronary vasodilators and diuretics, followed by digoxin and calcium antagonists. The prescription of coronary vasodilators and ACE-inhibitors was clearly increasing over the last 6 years. Beta blockers are rarely used in very old people.

Aged↗
PubMed1994

Ribozyme-mediated cleavage of the MDR-1 transcript restores chemosensitivity in previously resistant cancer cells.

How cancer cells become resistant to chemotherapy is not completely understood, but it is believed that resistance is usually associated with overexpression of drug resistance genes. Drug resistance mediated by the MDR-1 gene is the first well characterized form of drug resistance in human cancer. MDR-1 encodes a phosphoglycoprotein, P-GP, that serves as an energy-dependent drug efflux pump, reducing intracellular drug accumulation and thereby cytotoxicity. We have used ribozymes to reverse the multiple drug resistance phenotype. A hammerhead ribozyme recognizing the GUC sequence at position -6 to -4 close to the translation start site of the 4.5 kb MDR-1 mRNA was prepared by in vitro transcription (MDR-1-RZiv) or chemical synthesis (MDR-1-RZs). Both MDR-1-RZiv and MDR-1-RZs specifically cleaved the MDR-1 mRNA into two parts of the expected size under physiological conditions in an extracellular system with MDR-1-RZiv being more effective. Site-specific cleavage was dependent on time, temperature and [MgCl2]. To examine the in vivo potential of MDR-1-RZ, MDR-1-RZiv and MDR-1-RZs were transfected into a human pleural mesothelioma cell line and into one adriamycin-resistant and one vindesine-resistant subline thereof by liposome-mediated transfer. Incorporation of ribozymes resulted in significantly reduced expression of the MDR-1 gene, with MDR-1-RZs being more potent than MDR-1-RZiv in vitro. MDR-1-RZ reduces P-GP overexpression at the protein level. Liposome-mediated transfer of MDR-1-RZiv or MDR-1-RZs reversed the multiple drug resistance phenotype and restored sensitivity towards chemotherapeutic drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Transforming growth factor-beta relieves stem cell factor-induced proliferation of myelogenous leukemia cells through inhibition of binding of the transcription factor NF-jun.

Transforming growth factor-beta (TGF-beta) is a potent inhibitor of growth factor-stimulated hematopoiesis in normal and leukemic conditions. Using the factor-dependent myelogenous leukemia cell lines GF-D8 and Mo7, we show that TGF-beta interferes with stem cell factor (SCF)-induced proliferation by downmodulating c-jun gene expression. The ability of SCF to induce accumulation of c-jun transcripts was abolished when TGF-beta was present in culture. Transcriptional nuclear run-on assays indicated that TGF-beta relieved the capacity of SCF to enhance the transcriptional rate of the c-jun gene. Deletion analysis of the c-jun promoter furthermore showed that SCF was activating the c-jun promoter via the NF-jun transcription factor. Gel mobility shift assays showed that SCF increased the binding activity of NF-jun to its recognition site within 5 to 15 minutes. Binding activity peaked at 1 hour after exposure to SCF and declined to starting levels within 4 hours. The ability of SCF to enhance NF-jun binding activity was also dose-dependent in the range of 5 to 100 ng/mL. Exposure of GF-D8 and Mo7 cells to TGF-beta before the addition of SCF antagonized SCF-induced NF-jun binding. Moreover, whereas SCF was capable of functionally activating a heterologous promoter containing the NF-jun binding site, pretreatment of GF-D8 cells with TGF-beta abolished transcriptional activation of this heterologous promoter. These findings indicate that SCF-mediated activation of c-jun via NF-jun is crucial for the SCF-inducible proliferative response and is inhibited by TGF-beta. In additional experiments, the antisense technique was used. Treatment of GF-D8 and Mo7 cells with an antisense oligodeoxyribonucleotide directed against the translation initiation site of c-jun abolished the capacity of SCF to induce a proliferative response, whereas sense and nonsense oligomers had no effect. Taken together, our data indicate that the counteracting modulation of the binding activity of NF-jun by SCF and TGF-beta regulates the expression of the c-jun gene and thereby the proliferative state of the GF-D8 and Mo7 target.

Binding Sites↗
PubMed1994

Discordant adaptation of human peritoneal macrophages to stimulation by lipopolysaccharide and the synthetic lipid A analogue SDZ MRL 953. Down-regulation of TNF-alpha and IL-6 is paralleled by an up-regulation of IL-1 beta and granulocyte colony-stimulating factor expression.

Human peritoneal macrophages were exposed to increasing doses of LPS or a synthetic lipid A analogue (SDZ MRL 953) and production of the cytokines IL-1 beta, IL-6, TNF-alpha, and G-CSF was assessed at the protein and mRNA level. Cells were also prestimulated with low doses of LPS and SDZ MRL 953 to study their adaptation to a secondary challenge with high doses of LPS. The ability of macrophages to produce high levels of TNF-alpha and IL-6 after stimulation with LPS could be relieved almost completely by preincubating cells with low doses of LPS. Decreases of TNF-alpha and IL-6 production resulted from inhibition of gene transcription and/or changes in mRNA stability, as transcript levels of these cytokines were down-modulated by the process of LPS adaptation. Surprisingly, however, adapted cells were able to synthesize even larger quantities of G-CSF and IL-1 beta when exposed to a secondary LPS challenge. mRNA levels of the adapted cells remained unaltered for IL-1 beta, but were slightly increased for G-CSF as assessed by Northern blot analysis. High doses of the synthetic lipid A analogue SDZ MRL 953 were also able to adapt macrophages to a secondary LPS challenge by down-regulating TNF-alpha and IL-6 production, whereas priming secretion of G-CSF and IL-1 beta as well. We describe here the discordant adaptation of human peritoneal macrophages to a secondary LPS stimulus in vitro. These findings appear to have ramifications for the in vivo endotoxin response during inflammation and also Gram-negative septicemia.

Dinoprostone↗
PubMed1994

Interleukin-3 and granulocyte-macrophage colony-stimulating factor induce activation of the MAPKAP kinase 2 resulting in in vitro serine phosphorylation of the small heat shock protein (Hsp 27).

Interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have previously been reported to induce rapid phosphorylation of the mitogen-activated protein (MAP) kinase. However, little is known about signaling events initiated by both hematopoietins that occur downstream of the MAP kinase. MAP kinase has been shown to phosphorylate the AP-1 transcription factor and also to activate two kinases designated insulin-stimulated protein kinase-1 and MAP kinase-activated protein (MAP-KAP) kinase 2. We show here that IL-3 and GM-CSF induce MAPKAP kinase 2 activity in the human megakaryoblastic leukemia cell line MO7 and phosphorylate the human small heat shock protein Hsp 27 on serine residues in vitro. GM-CSF also induced Hsp 27 phosphorylation in neutrophils in a range similar to that observed in MO7 cells, suggesting that MAPKAP kinase 2-mediated Hsp 27 activation occurs independently of proliferation. Hsp 27 phosphorylation was dose-dependent, occurred as early as 5 minutes after factor exposure, and was inhibited by the tyrosine kinase inhibitors genistein and herbimycin A. Furthermore, the protein phosphatase A2 abolished IL-3- and GM-CSF-induced serine phosphorylation of Hsp 27. Taken together, our findings indicate that tyrosine phosphorylation of MAP kinase is a prerequisite for serine phosphorylation of Hsp 27, which is mediated by MAPKAP kinase 2. Hsp 27 has shown activation-dependent translocation from the cytosolic to the nuclear region and has been linked to the cellular stress response. However, its precise function is largely unknown. Our data identify Hsp 27 as a target of the IL-3/GM-CSF stimulation pathway that involves MAP kinase and MAPKAP kinase 2. In addition, our results indicate that Hsp 27 may be target of phosphorylation events not only in the stress response but also in unstressed cells responding to cytokine stimulation.

Benzoquinones↗
PubMed1994

Expression of the transforming growth factor-alpha gene by human eosinophils is regulated by interleukin-3, interleukin-5, and granulocyte-macrophage colony-stimulating factor.

Transforming growth factor (TGF)-alpha is a pleiotropic polypeptide which mediates a variety of tissue-specific cellular responses such as induction of proliferation, cell migration, vascularization, and formation of extracellular matrix. TGF-alpha is produced by certain tumor cells and embryogenic tissues, as well as by normal cells of different origin. Within the granulocytic lineage, TGF-alpha production has been shown in promyelocytic leukemia cells induced to differentiate, as well as in blood eosinophils of patients with the idiopathic hypereosinophilic syndrome. The present study was carried out in order to examine expression of the TGF-alpha gene in polymorphonuclear (PMN) and mononuclear (MN) blood cells of normal healthy donors. While MN and neutrophilic PMN failed to synthesize TGF-alpha transcripts and protein, eosinophils constitutively exhibited TGF-alpha transcripts accompanied by the release of immunoreactive TGF-alpha protein. Exposure of PMN and MN cells to the leukocyte-activating cytokines interleukin (IL)-3, IL-5, and granulocyte-macrophage colony-stimulating factor resulted in a several-fold increase of TGF-alpha mRNA expression and protein release by eosinophils, but not by neutrophils and MN cells. PMN and MN were insensitive to induction of TGF-alpha release by IL-8 and granulocyte colony-stimulating factor. These results point to a functional role of eosinophils in disorders characterized by unbalanced TGF-alpha production such as disease states associated with abnormal matrix formation and neovascularization which may be explained by the present demonstration of TGF-alpha production in these cells.

Cycloheximide↗
PubMed1994

High-dose consolidation with local radiation and bone marrow rescue in patients with advanced neuroblastoma.

Twenty-six children with advanced neuroblastoma were consolidated with cisplatin, BCNU, etoposide, melphalan, 21 Gy of local radiotherapy, and bone marrow rescue in a multicenter study. All patients were over 1 year of age at diagnosis. Twenty-two patients were treated in first complete or partial remission and four in second complete or partial remission. Hematologic rescue was autologous (n = 23), allogeneic (n = 2), or syngeneic (n = 1). Extrahematological toxicity involved primarily the gastrointestinal mucosa. Among five fatal toxicities, three included intestinal hemorrhage. Fourteen patients relapsed after BMT, four of them at the primary site. Seven children survive progression-free after 16-56 months. These results are essentially not different from a single-center study with the same protocol or from other published studies. The value of megatherapy for patients with advanced neuroblastoma or for a subgroup of them can only be established on a larger number of patients than most national trials accrue.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

P-glycoprotein-mediated multidrug resistance in normal and neoplastic hematopoietic cells.

The multidrug transporter, P-glycoprotein (P-gp), is expressed by CD34-positive bone marrow cells, which include hematopoietic stem cells, and in other cells in the bone marrow and peripheral blood, including some lymphoid cells. Multidrug resistance mediated by P-gp appears to be a major impediment to successful treatment of acute myeloid leukemias and multiple myelomas. However, the impact of P-gp expression on prognosis has to be confirmed in several other hematopoietic neoplasms. The role of P-gp in normal and malignant hematopoiesis and clinical attempts to circumvent multidrug resistance in hematopoietic malignancies are reviewed. The recent transduction of the MDR1 gene into murine hematopoietic cells, which protects them from toxic effects of chemotherapy, suggests that MDR1 gene therapy may help prevent myelosuppression following chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Post-transcriptional regulation of interleukin-6 gene expression in human keratinocytes by ultraviolet B radiation.

Exposure to increasing doses (290-315 nm) of ultraviolet (UV) B radiation is thought to profoundly affect human health. Studies on the biologic and molecular effects of UVB radiation on human skin are therefore of particular interest. There is experimental and clinical evidence to assume that UVB radiation-induced local and systemic inflammatory reactions might be mediated at least in part by UVB-induced keratinocyte-derived interleukin (IL)-6. Previously, a UVB-induced increase of steady-state levels of IL-6 mRNA was found to be a prerequisite for keratinocyte IL-6 production after UVB irradiation. The present study was aimed at addressing the question of whether in vitro UVB irradiation would increase IL-6 mRNA expression in long-term cultured, normal human keratinocytes via transcriptional or post-transcriptional mechanisms. UVB exposure (0-100 J/m2) of keratinocytes increased low baseline expression levels of IL-6 mRNA in a time- and dose-dependent manner. Using nuclear run-on assays, transcription rates of the IL-6 gene in nuclei isolated from UVB-irradiated cells were found to be essentially identical to those seen in unirradiated cells, indicating that UVB light did not lead to increased transcription of the IL-6 gene. To determine a possible post-transcriptional mechanism in UVB-induced IL-6 mRNA expression, the effects of UVB irradiation on IL-6 mRNA stability were examined. To this end irradiated and unirradiated keratinocytes were treated with actinomycin D and subjected to Northern blot analysis to calculate IL-6 mRNA half-life. As compared with unirradiated cells, IL-6 mRNA stability was increased significantly (three- to four-fold) in UVB-irradiated cells, suggesting that UVB radiation upregulates IL-6 mRNA levels in human keratinocytes by increasing the stability of IL-6 transcripts. This is the first report indicating that UVB radiation at a physiologically relevant dose may affect gene expression in human cells at a post-transcriptional level.

Blotting, Northern↗
PubMed1994

Hodgkin's disease: a cytokine-producing tumor--a review.

Cytokines and hematopoietic growth factors are actively involved in regulation of proliferation, differentiation, and cellular functions of various cell lineages. Each cytokine exhibits pleiotropic biological functions on different target cells and subfamilies of cytokines often have redundant biological effects on the same target cell. Hodgkin's disease represents one of the most common human lymphoma entities, the molecular pathogenesis of which is not well understood. Hodgkin's disease is characterized by the presence of typical, presumed malignant Hodgkin and Reed-Sternberg cells in a hyperplastic background of normal reactive lymphocytes, plasma cells, histiocytes, neutrophils, eosinophils, and stromal cells. The histopathological presentation and characteristic clinical features of Hodgkin's disease correlate with an unbalanced production of multiple cytokines. Hodgkin and Reed-Sternberg cells express mRNA and proteins of various cytokines, growth factors, and cytokine receptors, implying a predominant role for cytokines in the pathophysiology of Hodgkin's disease as a tumor of cytokine-producing cells.

Cytokines↗
PubMed1994

Raf-1 is a necessary component of the mitogenic response of the human megakaryoblastic leukemia cell line MO7 to human stem cell factor, granulocyte-macrophage colony-stimulating factor, interleukin 3, and interleukin 9.

We have examined the role of Raf-1 in the mitogenic response of the factor-deprived human megakaryoblastic leukemia cell line MO7 to recombinant human granulocyte-macrophage colony-stimulating factor, interleukin 3, interleukin 9, and stem cell factor by using c-raf antisense oligodeoxyribonucleotides. Uptake of oligodeoxyribonucleotides by MO7 cells was maximal at 5-10 h in culture, and oligomers remained stable in these cells for at least 24 h. Treatment of MO7 cells with the antisense oligomer resulted in intracellular oligomer/mRNA duplex formation followed by efficient translation blockade of c-raf-1. In contrast, sense and non-sense oligodeoxyribonucleotides failed to form intracellular duplexes and did not interfere with translation of c-raf-1, suggesting specific elimination of c-raf-1 by the antisense oligodeoxyribonucleotide. Furthermore, exposure of MO7 cells to c-raf-1 antisense prevented factor-induced nuclear translocation of Raf-1. Most importantly, proliferation of MO7 cells ([3H]thymidine incorporation) enabled by these growth factors was significantly reduced when the c-raf-1 antisense oligodeoxyribonucleotide was added to cultures, whereas the mitogenic response to these factors remained almost unaffected in the presence of sense and non-sense oligodeoxyribonucleotides.

Base Sequence↗
PubMed1994

Mechanisms of p53 alteration in acute leukemias.

Disruption of normal p53 expression is the most frequent genetic change occurring in various human solid tumors; it is mostly due to sequence alterations of the p53 coding region by missense mutations or to loss of an entire, functional allele of this gene. In the present study, possible mechanisms resulting in a disruption of regulated expression of wild-type p53 were examined in acute leukemias of either lymphoid (ALL) or myeloid (AML) phenotype. p53 transcript accumulation, nucleotide sequence and gene structure were analyzed in primary leukemic cells from 50 patients. p53-specific transcripts were detected in 26/26 cases of ALL and 16/23 cases of AML using reverse transcriptase (RT)-PCR. Sequencing of transcripts did not reveal any point mutations or deletions. Heterozygosity at a polymorphic Bg/II site within intron 1 was found in 4/28 leukemic samples, and loss of one allele was noted in one of these. In addition, a novel, leukemia-associated structural abnormality located within the 5' flanking region of the p53 gene and associated with the loss of heterozygosity was observed in cells from this patient with ALL. The MDM2 gene which inactivates p53 by binding to it was neither amplified nor rearranged in 28 leukemias studied. Thus, disruption of regulated p53 expression resulting in lack of detectable p53 mRNA even by RT-PCR occurs in about 30% of cases of AML; however, p53 alterations typical for human solid tumors are an infrequent event in most types of human acute leukemias.

Acute Disease↗
PubMed1994

Interleukin-1-induced intracellular signaling pathways converge in the activation of mitogen-activated protein kinase and mitogen-activated protein kinase-activated protein kinase 2 and the subsequent phosphorylation of the 27-kilodalton heat shock protein in monocytic cells.

Interleukin (IL)-1 plays a central role in human host defense. Binding of IL-1 to its receptor is associated with phosphorylation of various cellular target proteins, most of which are unidentified. The kinases responsible for target protein phosphorylation after IL-1 stimulation are also still not completely understood. We report here that IL-1 induced activation of mitogen-activated protein (MAP) kinase in primary monocytes and in the human monocytic leukemia cell line U-937. Activation of MAP kinase was followed by activation of MAP kinase-activated protein (MAPKAP) kinase 2, a serine/threonine kinase, leading to subsequent phosphorylation of the small heat shock protein [27-kDa heat shock protein (Hsp27)]. Phosphorylation of Hsp27 triggered by IL-1 was both dose and time dependent. IL-1 failed to phosphorylate Hsp27 when cells had been previously deactivated with tyrosine kinase inhibitors such as genistein. In those cells, however, Hsp27 phosphorylation could be reconstituted when activated immunoprecipitated MAP kinase or purified MAPKAP kinase 2 was added. Phosphorylation of Hsp27 could also be inhibited when NaF, a serine/threonine phosphatase inhibitor, was omitted. Taken together, our findings indicate that IL-1-induced intracellular signaling pathways converge in the activation of MAP kinase and MAPKAP kinase 2 and the subsequent phosphorylation of Hsp27.

Cell Line↗
PubMed1994

Burkitt-like mutations in the c-myc gene locus in prolymphocytic leukemia.

The c-myc oncogene recently shown to act as a transcription factor, is involved in cellular proliferation. Deregulation of this gene can be one step in malignant transformation. In Burkitt's lymphoma (BL) the c-myc gene is consistently involved in chromosomal translocations and the first exon of the gene has been found to be a frequent target of somatic mutations. These mutations are believed to interfere with normal transcriptional regulation of the gene. We demonstrate a case of the rare prolymphocytic leukemia (PLL), a variant of chronic lymphocytic leukemia (CLL), that shows multiple Burkitt-like mutations in the first exon of c-myc and one nonconservative point mutation in the coding exon 2. Cytogenetic analysis revealed involvement of both chromosomes 8 in chromosomal translocations. Both chromosomes 8 are broken at (q23), the c-myc gene locus. Since the patient's leukemia cells exhibited high expression levels of the mutated allele of the c-myc mRNA, the point mutations alone may have accounted for transcriptional deregulation.

Amino Acid Sequence↗
PubMed1993

Equine infectious anemia virus Tat is a predominantly helical protein.

Nuclear magnetic resonance (NMR) spectroscopy revealed features of the secondary structure of the equine infectious anemia virus (EIAV) Tat protein in solution. We could show that this protein, which is required in the replication cycle of lentiviruses, forms a predominantly helical structure in trifluoroethanol/water (40% by vol.) solution. In particular, the basic RNA-binding region and the adjacent core domain, which are highly conserved among lentiviral Tat proteins, show helix-type secondary structure under these conditions. Our observations, in concert with recent biochemical data from other laboratories, suggest that the core sequence region and the basic sequence region form interdependent structural domains, both possibly necessary for correct RNA binding.

Amino Acid Sequence↗