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Biomedical subjects

E Thiel

Publications and source records attributed to E Thiel.

At least 109 records · Page 6Linked to original sources
PubMed1998

De novo expression of the alpha5beta1-fibronectin receptor in HT29 colon-cancer cells reduces activity of C-SRC. Increase of C-SRC activity by attachment on fibronectin.

Changes in integrin expression during malignant transformation have been observed in many tumors. Colon-carcinoma cells show reduced expression or even loss of the alpha5beta1 integrin compared to normal or adenoma cells. To determine the significance of absent alpha5beta1 integrin signaling, we transfected the cDNA coding for the alpha5 integrin sub-unit into the human colon-carcinoma cell line HT29, which constitutively lacks this subunit but does express the beta1 subunit. We show here that the newly expressed fibronectin receptor alpha5beta1 generates multiple signals, causing marked changes in cytoskeletal arrangements within a few minutes of adhesion to fibronectin. Cells expressing the alpha5beta1 integrin exhibit the formation of actin stress fibers and focal adhesions, as well as the induction of tyrosine phosphorylation of several proteins, within 10 min. We identified the focal adhesion kinase pp125FAK and the cytoskeletal protein paxillin as major phosphorylation substrates in these cells. These proteins remained hypophosphorylated when alpha5-negative control cells were plated on fibronectin. The tyrosine kinase pp60c-src, regarded as central in the regulation of cellular proliferation and constitutively over-expressed in HT29 and in colon-carcinoma cells, showed reduced intrinsic kinase activity in unstimulated HT29alpha5 cells. In contrast, fibronectin-induced signaling through alpha5beta1 increased pp60c-src activity. Moreover, immunoprecipitation of pp60c-src from extracts of HT29alpha5 cells cultivated on fibronectin for 20 min revealed complex formation of pp60c-src and tyrosine-phosphorylated pp125FAK. Our data suggest that de novo expression of the alpha5beta1 integrin in HT29 colon-cancer cells restores signaling via pp125FAK and pp60c-src. Thus, loss of this receptor during malignant transformation may contribute to tumor-cell autonomy, while reduced activity of pp60c-src in HT29alpha5-cells may participate directly in growth control.

Cell Adhesion↗
PubMed1998

Cryptococcosis in Hodgkin's disease: description of two cases and review of the literature.

Systemic mycosis caused by Cryptococcus neoformans frequently becomes life threatening in patients with cellular immunodeficiencies. In contrast to AIDS patients, there are only a few reports of concurrent systemic cryptococcosis in patients with Hodgkin's disease (HD). Only two of 75 (2.7%) patients with HD who were consecutively admitted to our hospital in the past decade developed Cryptococcus neoformans infection. Both had stage IVB (Ann Arbor) HD with bone marrow involvement and absolute lymphopenia (< 1/nl). We have reviewed the literature and analyzed the data of 54 cases with concurrent cryptococcosis and HD. Presence of HD for > or = 12 months, stage IV disease, absolute lymphopenia (< 1/nl), and extensive pretreatment were the most common features among these patients and must be regarded as predisposing for acquiring a cryptococcal infection. In our patients antimycotic therapy was successful using liposomal amphotericin B (lipAmB) simultaneously with cytotoxic therapy for HD. Drug level measurements performed in one patient revealed a higher level of amphotericin B in CSF when the liposomal formulation was administered as compared with the level in CSF after administration of conventional amphotericin B. To our knowledge, this is the first report on antimycotic treatment of cryptococcosis with lipAmB in patients with HD. Regarding the favorable therapeutic index of lipAmB as compared with conventional amphotericin B, the drug should be considered as a less toxic and perhaps more effective alternative in the therapy of acute cryptococcosis, especially when cytotoxic treatment is administered simultaneously.

Adult↗
PubMed1998

Integrin alpha5beta1: a potent inhibitor of experimental lung metastasis.

The integrin alpha5beta1 seems to be the most relevant receptor of tumor cells for binding to fibronectin. Although numerous studies suggest a role of tumor cell fibronectin interaction in tumor metastasis, differential integrin expression on tumor cells has, however, not been correlated with metastatic capabilities. We addressed this question by transfection of the integrin alpha5beta1 cDNA into HT-29 human colon carcinoma cells which led to de novo expression of functional integrin alpha5beta1. Similar to other reports, expression of the integrin alpha5beta1 in HT-29 tumor cells exerted an inhibitory action on cell proliferation as indicated in our study by formation of fewer colonies in soft agar. The tumor growth inhibitory property of the integrin alpha5beta1 was also shown by reduction of subcutaneous xenograft growth in nude mice to approximately 50% of that of control transfectants. For the first time, we found that several clones of integrin alpha5 subunit transfectants displayed dramatically reduced formation of lung colonies and cutaneous metastasis after intravenous injection into nude mice. While most animals inoculated with control transfectant cells formed macroscopically visible lung colonies ranging from 12.6 +/- 2.6 to 22.0 +/- 6.6 (mean colony number +/- SEM), mice inoculated with HT-29 cell clones expressing the integrin alpha5beta1 were almost completely free of lung colonies (ranging from 0.0 +/- 0 to 0.2 +/- 0.1). Our results imply that integrin alpha5beta1 expression inhibits circulating tumor cells in pursuing late steps of the metastatic process as represented by the artificial metastasis (lung colonisation) model.

Animals↗
PubMed1998

Adhesion molecules on peripheral blood-derived CD34+ cells: effects of cryopreservation and short-term ex vivo incubation with serum and cytokines.

The homing of hematopoietic precursor cells (HPC) within the bone marrow is most likely to be mediated by specific adhesion via surface receptors to cellular and extracellular matrix (ECM) components and to be regulated by cytokines. We investigated the effects of serum and cytokines on the expression of adhesion molecules on cryopreserved and fresh peripheral blood-derived progenitor cells (PBPC) and on the adhesion of PBPC to various ECM proteins. PBPC were collected from patients by leukapheresis during G-CSF-supported recovery from conventional cancer chemotherapy. Freezing markedly reduced the fraction of CD34+ cells with L-selectin (CD62L) expression from 62 to 11% and also diminished the fluorescence intensity for the integrin subunits CD29 and CD49d on CD34+ cells. A 14 h incubation of thawed PBPC with serum induced re-expression of adhesion molecules. The addition of the cytokine cocktails (G-CSF + SCF + IL-3 + IL-11 or IL-4 + IL-1beta + IFN-gamma) or MGDF, however, exerted no effects in addition to serum alone. Furthermore, when compared to serum alone, the addition of cytokine cocktails or MGDF did not alter the fraction of fresh PB-CD34+ cells adhering to collagen I, collagen IV, fibronectin, laminin or vitronectin. HPC adhesion to ECM components might be refractory to short-term alterations of the cytokine environment. Alternatively, longer incubation times or other cytokines may be necessary to modulate the expression of adhesion molecules on hematopoietic progenitor cells or adhesion itself under ex vivo conditions.

Antigens, CD34↗
PubMed1998

High rate of chromosome abnormalities detected by fluorescence in situ hybridization using BCR and ABL probes in adult acute lymphoblastic leukemia.

The value of dual-color fluorescence in situ hybridization (FISH) with BCR and ABL probes for the detection of the Philadelphia (Ph) translocation and of other alterations involving ABL and/or BCR was evaluated in adult acute lymphoblastic leukemia (ALL). One hundred and four patients were studied prospectively using interphase nuclei FISH, chromosome analysis (CA), and PCR assays for the chimeric BRC/ABL transcript. FISH detected a Ph translocation in 24 cases (23.1%), as was confirmed by CA and/or PCR. FISH revealed a false positive diagnosis of a Ph translocation in four cases (5% false positive rate). Among 54 cases with combined FISH, CA and PCR assays, FISH failed to establish a correct diagnosis in 3.7%, PCR in 5.6%, and CA in 7.4%. The combination of two screening methods led to discrepant results in 9.3% (FISH + PCR), 11.1% (FISH + CA), or 13% (CA + PCR) of the cases. In seven of 80 (8.8%) Ph-negative patients, gain of BCR and/or ABL was identified. Overall, FISH detected alterations of the BCR and/or ABL genes with an incidence of 29.8% of the current study. Due to the possibility of false positive diagnosis of a Ph translocation using dual-color FISH the combination with chromosome and/or RT-PCR analyses is recommended in adult ALL patients.

Adolescent↗
PubMed1998

Distinction of eosinophilic leukaemia from idiopathic hypereosinophilic syndrome by analysis of Wilms' tumour gene expression.

In patients presenting with immature eosinophilic precursors it is notoriously difficult to distinguish acute eosinophilic leukaemia (EoL) from the benign idiopathic hypereosinophilic syndrome (HES), based on morphological, cytochemical and immunophenotyping criteria, alone. Cytogenetic analysis or fluorescence in situ hybridization (FISH) can help in discriminating between these rare haematological disorders, but often treatment decisions cannot wait for the results of these time-consuming techniques. Recently, we and others found Wilms' tumour (WT1) gene expression to be increased in virtually all patients with acute leukaemias, whereas normal haemopoietic progenitors express the WT1 gene at much lower levels or not at all. To determine whether detection of WT1 gene expression is useful to distinguish EoL from HES patients, we analysed, by RT-PCR, bone marrow or blood mononuclear cells from EoL (n=3), HES (n=3) and reactive eosinophilia patients (n = 4) for WT1 gene expression. Using our WT1-RT-PCR protocol, we found WT1 gene expression to be restricted to EoL patients. By detecting WT1 mRNA transcripts in the cerebrospinal fluid using RT-PCR, we were also able to diagnose isolated CNS-relapsed leukaemia, initially confused with bacterial meningitis, in an EoL patient. In conclusion, we show that WT1-RT-PCR is a powerful complementary diagnostic tool to distinguish acute eosinophilic leukaemia from the hypereosinophilic syndromes. This observation needs confirmation in a larger series of EoL and HES patients.

Adult↗
PubMed1998

Successful treatment of non-Hodgkin's lymphoma of the central nervous system with BMPD chemotherapy followed by radiotherapy.

The treatment of patients with primary non-Hodgkin's lymphoma of the central nervous system (PCNSL) is still of limited success, as compared with other extranodal sites. The poor results obtained with radiotherapy alone can be improved by adding chemotherapy reaching a median survival up to over 30 months and 5-years-survival rate up to 35%. The optimal management for patients with CNS relapse of systemic lymphoma remains uncertain and their prognosis is even worse. Here, we describe our preliminary data on the treatment of patients with CNS lymphoma with a new regimen composed of CNS-penetrating drugs, namely: carmustine (BCNU) 80 mg/m2 i.v. dl, methotrexate 1500 mg/m2 over 24h i.v. d2, procarbacine 100 mg/m2 p.o. d1-8, and dexamethasone 3 x 8 mg p.o. d1-14. An average of 3 treatment courses were given under response control seen using CT-scan or NMR. Patients with positive CSF cytology received additionally intrathecal therapy with methotrexate. Until now between March 1994 and September 1997, 7 patients with PCNSL and 4 patients with CNS relapse of systemic lymphoma have been treated. The median age of the patients was 56 (range, 39-74); 5 patients were > or =60 years old. Three patients had multifocal disease. Whole brain radiotherapy with 4000 to 5000 cGy was given in 7 patients (cerebrospinal in 1 patient). Complete response at the end of chemotherapy was achieved in 6 patients, and a partial response in two. Most remarkably, 2 elderly patients (70 and 57 years), 1 patient with multifocal disease and 1 with simultaneous CNS and systemic relapse after chemotherapy had a complete remission lasting for 40 months, and a partial remission lasting for 37 months, respectively.

Adult↗
PubMed1998

Phase I clinical and pharmacokinetic study of titanocene dichloride in adults with advanced solid tumors.

This Phase I dose-escalation clinical trial of a lyophilized formulation of titanocene dichloride (MKT4) was conducted to determine the maximum tolerated dose, the dose-limiting toxicity (DLT), and pharmacokinetics of titanium (Ti) after a single i.v. infusion of MKT4. Forty patients with refractory solid malignancies were treated with a total of 78 courses. Using a modified Fibonacci scheme, 15 mg/m2 initial doses of titanocene dichloride were increased in cohorts of three patients up to level 11 (560 mg/m2) if DLT was not observed. The maximum tolerated dose was 315 mg/m2, and nephrotoxicity was DLT. Two minor responses (bladder carcinoma and non-small cell lung cancer) were observed. The pharmacokinetics of plasma Ti were assessed in 14 treatment courses by atomic absorption spectroscopy. The ratio for the area under the curve(0-infinity) in plasma and whole blood was 1.2. The following pharmacokinetic parameters were determined for plasma, as calculated in a two-compartment model: biological half-life t1/2beta in plasma was 22.8+/-11.2 h (xh +/- pseudo-SD), peak plasma concentration cmax approximately 30 microg/ml at a dose of 420 mg/m2, distribution volume Vss= 5.34+/-2.1 L (xa +/- SD), and a total clearance CItotal = 2.58+/-1.23 ml/min (xa +/- SD). There was a linear correlation between the area under the curve(0-infinity) of Ti in plasma and the titanocene dichloride dose administered with a correlation coefficient r2 of 0.8856. Plasma protein binding of Ti was in the 70-80% range. Between 3% and 16% of the total amount of Ti administered were renally excreted during the first 36 h. The recommended dose for Phase II evaluation is 240 mg/m2 given every 3 weeks with i.v. hydration to reduce renal toxicity.

Adult↗
PubMed1998

Activation of autologous lymphocytes of patients with chronic myelogenous leukemia in the chronic phase with cytokines and CD3 monoclonal antibody results in bcr/abl- blood leukocyte cultures as determined by reverse transcriptase-polymerase chain reaction.

To investigate the potential of autologous lymphocytes to eliminate chronic myelogenous leukemia (CML) cells following activation and targeting by CD3-monoclonal antibody, we cultured Ficoll-isolated peripheral blood cells from 11 patients with CML in the chronic phase in permutated combinations of interleukin (IL)-2, CD3-monoclonal antibody (OKT3), and interferon (IFN)gamma. The efficiency of CML cell elimination was studied by means of flow cytometry and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Cultures containing only OKT3 and IL-2, with or without IFNgamma, resulted in tumor cell reduction to the level of RT-PCR negativity. The length of the culture period required to reach a RT-PCR-negative state ranged from 3 to 33 days. A 1- to 2-log reduction in leukemic cells could be achieved by culture medium alone. In contrast, 3- to 4-log reductions in CML cells were observed following in vitro culture and ex vivo T cell activation with a given sensitivity for RT-PCR detection of 1 bcr/abl+ cell in 10(4). The feasibility of purging chronic myelogenous leukemia cells in a short time was associated with a low number of platelet counts (r=0.6457; p < 0.05). CML cell reduction was associated with expansion of CD25+/CD4+//CD8+/-/CD56+/- lymphocytes. These findings may be of relevance for immunotherapy procedures.

Adult↗
PubMed1997

Autocrine interleukin-1 receptor antagonist can support malignant growth of glioblastoma by blocking growth-inhibiting autocrine loop of interleukin-1.

In situ hybridization (ISH) of human glioblastoma tissue sections revealed expression of interleukin-1 (IL-1)alpha and/or beta and IL-1 receptor types I and II (IL-1R I and II) in the majority of cases evaluable. To understand the function of IL-1-family members in human glioblastomas, we have studied 6 glioblastoma cell lines. RT-PCR, ISH, ELISA and 125I-IL-1-binding assays revealed expression of IL-1 and high-affinity receptors for human (h)IL-1 in all but 1 cell line. Using a colony growth assay in semi-solid media for testing serial plating efficacy (PE, number of colonies per number of cells seeded in %), only the IL-1R-negative cell line was not influenced by recombinant human (rh)IL-1alpha or -beta, whereas IL-1 down-regulated the self-renewal of clonogenic cells of the other glioblastomas. Tritiated thymidine uptake was down-regulated by rhIL-1 in all cell lines studied. Cell viability remained unchanged by rhIL-1. Wherever growth modulation by rhIL-1 was detected, it could be reversed by either soluble IL-1R I or II or by rhIL-1 receptor antagonist (ra). IL-1ra not only was able to reverse rhIL-1-induced growth modulation but alone could modulate glioblastoma growth in comparison with control in cell lines producing IL-1. Our results show the presence of public autocrine loops for IL-1 leading to growth inhibition in some glioblastomas. To understand these loops, we have studied expression and function of IL-1ra in glioblastomas. ISH of human glioblastoma tissue sections revealed expression of hIL-1ra in all 8 cases evaluable. In 4 of 6 cell lines, IL-1ra was found in the supernatant under constitutive conditions, the IL-1R-negative line being among the 2 non-producers. The other non-producing cell line, HTB 17, showed expression of hIL-1R II. Most interestingly, a neutralizing antibody against IL-1ra down-regulated growth of IL-1- and IL-1ra-producing glioblastoma cells to approx. 30% of the controls. Thus, public autocrine loops for IL-1 in human glioblastomas exist and result in growth inhibition. An autocrine production of IL-1-antagonizing molecules such as IL-1ra by these tumors can counteract this IL-1 function and represent a basic escape mechanism supporting malignant growth in some glioblastomas.

Binding Sites↗
PubMed1997

Subclassification of diffuse large B-cell lymphomas according to the Kiel classification: distinction of centroblastic and immunoblastic lymphomas is a significant prognostic risk factor.

Among high-grade malignant non-Hodgkin's lymphomas the updated Kiel classification identifies three major B-cell entities: centroblastic (CB), B-immunoblastic (B-IB), and B-large cell anaplastic (Ki-1+) (now termed anaplastic large cell [CD30+], [B-ALC]). The clinical prognostic relevance of this distinction was evaluated in a randomized prospective treatment trial (COP-BLAM/IMVP-16 regimen randomly combined +/- radiotherapy in complete responders) conducted in adult (age 15 to 75) patients with Ann Arbor stage II-IV disease (n = 219) diagnosed by optimal histomorphology (Giemsa staining) and by immunohistochemistry. Overall survival was significantly better in CB lymphoma as compared to B-IB (P = .0002) or B-ALC (P = .046). Relapse-free survival was worse for B-IB (P = .0003) as compared to CB lymphomas. The prognostic differences between CB and B-IB were confirmed by multivariate analyses including the risk factors of the International Index. Overall survival was significantly determined by performance status (P = .0003), serum-LDH (P = .036), and B-IB histology subtype (P = .036). Relapse-free survival was influenced by age (P = .007) and histological subtype (P = .007). Thus, the diagnosis of the CB and B-IB lymphomas by the histological criteria of the Kiel classification was identified as an independent prognostic factor in diffuse large B-cell lymphomas.

Adolescent↗
PubMed1997

Detection by monoclonal antibodies of the Wilms' tumor (WT1) nuclear protein in patients with acute leukemia.

The WT1 gene encodes a transcriptional regulator which during embryogenesis is involved in growth control and differentiation of diverse tissues. It is also expressed in few human malignancies, including acute leukemia. We tested 3 different monoclonal antibodies (MAbs H2, H7, HCl7) and the polyvalent serum WTC-19 for WT1 protein detection in mononuclear cell (MNC) preparations of 104 newly diagnosed acute leukemia patients. Using RT-PCR, these MNC preparations were also analyzed for WT1 gene expression. MAbs H2, H7 and HCl7 and the polyclonal WTC-19 exhibited nuclear immunoreactivity in 63 of 99, 28 of 56, 38 of 60 and 22 of 43 WT1 gene-expressing leukemia samples, respectively. With these antibodies, no WT1 immunoreactivity was found in MNCs from blood of healthy volunteers, from CD34+ progenitor cell-enriched leukapheresis products of patients conditioned for peripheral stem cell harvest or from reactive bone marrow. Contrary to WTC-19, all MAbs reacted highly specifically with the WT1 protein (0.71 vs. 1.0). The WT1 protein was heterogeneously detected in leukemia blast preparations by all antibodies, irrespective of cell morphology. Very few HL60 cells and blasts from newly diagnosed leukemia patients interspersed among normal blood MNCs (50 blasts among 5 x 10(5) MNCs) were easy to identify by indirect immunofluorescence using MAbs H2 and HCl7. Taken together, MAbs H2 and HCl7 were superior to MAb H7 and the polyvalent WTC-19 in detecting the WT1 nuclear protein.

Antibodies, Monoclonal↗
PubMed1997

Five-day continuous infusion of 5-fluorouracil and pulsed folinic acid in patients with metastatic colorectal carcinoma: an effective second-line regimen.

OBJECTIVE: A previous phase I trial in 14 pretreated patients with progressive advanced colorectal cancer demonstrated 750 mg/m2 to be the maximum tolerable dose of 5-fluorouracil (5-FU) administered as a five-day continuous infusion modulated by short infusions of 100 mg/m2 folinic acid twice daily. The dose-limiting toxicities were hand-foot syndrome and severe mucositis. A response rate of 21% and 50% stable disease could be achieved. In order to determine the effectiveness and tolerability, we initiated a multicenter phase II trial applying a 650 mg/m2 recommended dose of 5-FU and 100 mg/m2 folinic acid twice daily every three weeks. PATIENTS AND METHODS: From January 1994 to July 1996, 88 advanced and progressive colorectal cancer patients either previously treated with a bolus schedule of 5-FU and folinic acid (34 patients) or without (54 patients) previous chemotherapy were included in this trial. RESULTS: In the group of previously treated patients, therapy led to 6% (2 of 34 patients) remissions while stable disease could be observed in 68% (23 of 34 patients) of the patients. The median survival time was 14 months. The main toxicity was mucositis grade 3 in 15% of the previously treated patients and 10% in the nonpretreated patients. In the population of nonpretreated patients, the overall response rate was 15% (eight of 54 patients) and stable disease could be induced in 67% (36 of 54 patients). The median survival time was 13.7 months. CONCLUSION: This regimen is an active second-line therapy in advanced colorectal cancer with minimal toxicity, thus preserving the quality of life during palliative chemotherapy. Antitumor activity in previously untreated patients does not seem superior to that obtained with weekly regimens applying 24- or 48-hour continuous infusions of 5-FU and folinic acid.

Adult↗
PubMed1997

The efficiency of tumor cell purging using immunomagnetic CD34+ cell separation systems.

Immunomagnetic separation with anti-CD34 monoclonal antibodies and paramagnetic microbeads has been used to enrich hematopoietic stem cells from human bone marrow (BM) or mobilized peripheral blood mononuclear cells (PBMNC). The introduction of this technique also constitutes a new principle of tumor cell purging. The efficiency in terms of purging tumor cells from PBMNC was evaluated in seven different experiments. Mobilized (chemotherapy and G-CSF) PBMNC were collected from patients with solid tumors (n = 6) and multiple myeloma (n = 1) by leukapheresis using an automated MNC separation system and contaminated with 1% (n = 5) or 10% (n = 2) tumor cells from different epithelial cell lines being CD34-negative. The cell mixture was sensitized with anti-CD34 (9C5) antibodies and sheep anti-mouse IgG1 paramagnetic microspheres and enriched for CD34+ cells using an Isolex 50 magnetic separator. Purify of CD34+ cells was studied by flow cytometry (FACScan) and tumor cell depletion was evaluated by comparative human tumor cloning assays (HTCA) containing methylcellulose and agar. We achieved a median purity of CD34+ cells of 85.9% (range 69.8-92.9%) and a median yield of 48.1% (range 21.0-85.2%). From these data in each case the estimated log depletion of tumor cells was calculated and compared with the experimentally achieved (HTCA) log depletion (log delta depletion = log experimental depletion--log calculated depletion). In our experiments we achieved a median depletion of 2.75 log (range 1.55-3.69 log). When corrected for CD34+ cell yield of each experiment we observed a median 'yield corrected depletion' of 2.38 log (range 1.48-3.15 log). The following delta depletion values were obtained: +0.32 log (HTB 129, breast), +0.21 log (HTB 26, breast), +0.04 log (HTB 26) for experiments with higher experimental depletion, and -0.23 log (HTB 26), -0.9 log (HTB 26, PBMNC from patient with multiple myeloma), -0.82 log (HTB 131, breast) and -1.66 log (HTB 131) for lower depletion efficacy than calculated. These data suggest that depletion may depend on specific cell surface characteristics of tumor cells. Moreover, plasma factors (eg paraprotein) may also have some impact. In summary, the Isolex 50 provides a high purity of CD34+ cells and depletion of tumor cells was efficient. However, calculated and experimental purging efficiencies are not necessarily identical.

Antigens, CD34↗