Search PubMed⌕ Search

Biomedical subjects

R Hehlmann

Publications and source records attributed to R Hehlmann.

At least 19 recordsLinked to original sources

Detection of Aspergillus DNA in cerebrospinal fluid from patients with cerebral aspergillosis by a nested PCR assay.

Invasive aspergillosis (IA), a complication with high mortality rates, especially in disseminated IA with cerebral involvement, is difficult to diagnose. Biopsy of cerebral lesions is often not feasible, and culture of Aspergillus spp. from cerebrospinal fluid (CSF) is frequently negative. New molecular methods have emerged for diagnosing IA. So far, there are only few reports of Aspergillus DNA detection in CSF. After modifying the DNA extraction protocol, we detected Aspergillus DNA in CSF samples by a previously described nested PCR assay. In six patients with hematologic malignancy and cerebral aspergillosis, CSF samples were investigated for Aspergillus DNA. IA was classified according to the EORTC/MSG 2002 criteria. Two patients each had proven, probable, and possible IA. Thirty-five CSF samples were investigated for Aspergillus DNA by nested PCR. Samples with positive results in the nested PCR assay were quantified by LightCycler PCR assay. Fourteen CSF samples showed positive results in the nested PCR assay. Of these, six samples gave positive results in real-time PCR. The range of CFU per ml was 2,154 to 63,100,000. The highest number of CFU per ml was found in a CSF sample of a patient with acute lymphocytic leukemia and probable cerebral aspergillosis. Detection of Aspergillus DNA in CSF samples is thus possible and has the potential to improve diagnosis of cerebral aspergillosis. Further prospective studies with larger numbers of patients must be performed to evaluate the clinical significance of Aspergillus PCR with CSF samples.

Adolescent↗

Gene expression signature of primary imatinib-resistant chronic myeloid leukemia patients.

Although the selective tyrosine kinase inhibitor imatinib is successfully used in the treatment of chronic myeloid leukemia (CML), inherent mechanisms confer primary resistance to leukemic patients. In order to search for potentially useful genes in predicting cytogenetic response, a retrospective gene expression study was performed. Leukocyte RNA isolated before imatinib from interferon-alpha-pretreated chronic phase CML patients (n=34) with or without major cytogenetic remission (< or =35% Philadelphia (Ph)+ metaphases) during the first year of treatment was comparatively analyzed using Affymetrix U133A chips. Using support vector machines for gene classification, an outcome-specific gene expression signature consisting of 128 genes was identified. Comparative expression data of specific genes point to changes in apoptosis (e.g. casp9, tumor necrosis factor receptor-associated protein 1, hras), DNA repair (msh3, ddb2), oxidative stress protection (glutathione synthetase, paraoxonase 2, vanin 1) and centrosomes (inhibitor of differentiation-1) within primary resistant patients. Independent statistical approaches and quantitative real-time reverse transcriptase-polymerase chain reaction studies support the clinical relevance of gene profiling. In conclusion, this study establishes a candidate predictor of imatinib resistance in interferon-alpha-pretreated CML patients to be subjected to future investigation in a larger independent patient cohort. The resulting expression signature point to involvement of BCR-ABL-independent mechanisms of resistance.

Antineoplastic Agents↗

Cytogenetic response to prior treatment with interferon-alpha is predictive for survival after allogeneic hematopoietic stem cell transplantation in chronic myeloid leukemia.

We investigated the impact of a cytogenetic response (CyR) to IFN prior to and at the time of allogeneic hematopoietic stem cell transplantation (HSCT) on transplant-related mortality (TRM), relapse rate and survival probability after HSCT in 162 transplanted patients with chronic myeloid leukemia. One-hundred-one patients (62.3%) achieved a CyR prior to HSCT. Survival probabilities were higher in patients, who achieved any CyR prior to HSCT than in patients without CyR (63.6 vs 49.2%: P = 0.019). Survival probabilities in patients, who achieved a major CyR were better than in patients with minimal and minor CyR or in patients with no CyR (69.4 vs 58.8% vs 49.2%: P = 0.040). TRM and survival of chronic phase patients without CyR at the time of HSCT were similar to that of patients transplanted in advanced phase. Both groups combined had an outcome inferior to patients with at least minimal CyR (TRM, Gray test: P = 0.016, survival, log-rank test: P = 0.002). Univariate and multivariate analyses identified CyR prior to or at HSCT as a strong and independently favorable prognostic factor. We therefore conclude that allogeneic HSCT in CyR should be investigated prospectively as an alternative treatment option in defined patient groups.

Hematopoietic Stem Cell Transplantation↗

Gene expression profiling of CD34+ cells identifies a molecular signature of chronic myeloid leukemia blast crisis.

Despite recent success in the treatment of early-stage disease, blastic phase (BP) of chronic myeloid leukemia (CML) that is characterized by rapid expansion of therapy-refractory and differentiation-arrested blasts, remains a therapeutic challenge. The development of resistance upon continuous administration of imatinib mesylate is associated with poor prognosis pointing to the need for alternative therapeutic strategies and a better understanding of the molecular mechanisms underlying disease progression. To identify transcriptional signatures that may explain pathological characteristics and aggressive behavior of BP blasts, we performed comparative gene expression profiling on CD34+ Ph+ cells purified from patients with untreated newly diagnosed chronic phase CML (CP, n=11) and from patients in BP (n=9) using Affymetrix oligonucleotide arrays. Supervised microarray data analysis revealed 114 differentially expressed genes (P<10(-4)), 34 genes displaying more than two-fold transcriptional changes when comparing CP and BP groups. While 24 of these genes were downregulated, 10 genes, especially suppressor of cytokine signalling 2 (SOCS2), CAMPATH-1 antigen (CD52), and four human leukocyte antigen-related genes were strongly overexpressed in BP. Expression of selected genes was validated by real-time-polymerase chain reaction and flow cytometry. Our data suggest the existence of a common gene expression profile of CML-BP and provide new insight into the molecular phenotype of blasts associated with disease progression and high malignancy.

Adult↗

BBR 3438, a novel 9-aza-anthrapyrazole, in patients with advanced gastric cancer: a phase II study group trial of the Central European Society of Anticancer-Drug Research (CESAR).

BBR 3438, a member of the 9-aza-anthrapyrazole family designed to decrease anthracycline dependent cardiotoxicity and to improve efficacy provided high in vivo activity in gastric carcinoma xenograft models. The present study was carried out to assess the efficacy and safety of BBR 3438 applied at a dose of 50 mg/m(2) four-weekly as an 1-hour infusion to pretreated patients with gastric cancer. Twenty-seven patients received at least one administration of BBR 3438. Lymph nodes and liver were the most common sites of metastases. A total of 94 cycles were administered (median 2, range 1-6). The main toxicity consisted of (worst per patient [%]; NCIC CTC grades 1/2/3/4) neutropenia 7/7/19/52 (one case of febrile neutropenia), stomatitis 15/19/4/-, nausea 22/26/7/-, vomiting 19/7/7/-, alopecia 15/33/-/-. Neutrophil nadir (520/mul) was reached after a median 15 days. The median time to recovery to < or = grade 1 neutropenia was 13.5 days. The median average cumulative dose of BBR 3438 was 166.8 mg, and the median dose intensity was 48.8 mg/m(2). Left ventricular ejection function (LVEF) was monitored with multiple-gated angiography (MUGA). Median LVEF values at baseline and at the end of cycle 2 were 67.5% and 65%, respectively, and no patient showed a relevant decrease of LVEF. In 25 patients evaluable for response no remission was observed. Four patients (16%) had stable disease. Median time to progression was 51 days, median overall survival was 64 days. In all, the feasibility and tolerability of BBR 3438 applied 4-weekly at a dose of 50 mg/m(2) was confirmed and neither relevant LVEF decreases nor hints of cardiac toxicity were observed. In terms of antitumor activity, BBR 3438 was found to be ineffective in the treatment of gastric cancer.

Adult↗

The t(8;17)(p11;q23) in the 8p11 myeloproliferative syndrome fuses MYO18A to FGFR1.

The 8p11 myeloproliferative syndrome (EMS) also known as stem cell leukemia-lymphoma syndrome (SCLL) is associated with translocations that disrupt FGFR1. The resultant fusion proteins are constitutively active tyrosine kinases, and different FGFR1 fusions are associated with subtly different disease phenotypes. We report here a patient with a t(8;17)(p11;q23) and an unusual myelodysplastic/myeloproliferative disease (MDS/MPD) characterized by thrombocytopenia due to markedly reduced size and numbers of megakaryocytes, with elevated numbers of monocytes, eosinophils and basophils. A novel mRNA fusion between exon 32 of the myosin XVIIIA gene (MYO18A) at chromosome band 17q11 and exon 9 of FGFR1 was identified. Partial characterization of the genomic breakpoints in combination of bubble-PCR with fluorescence in situ hybridization revealed that the t(8;17) arose from a three-way translocation with breaks at 8p11, 17q11 and 17q23. MYO18A-FGFR1 is structurally similar to other fusion tyrosine kinases and is likely to be the causative transforming lesion in this unusual MDS/MPD.

Aged↗

Gender aspects in chronic myeloid leukemia: long-term results from randomized studies.

Gender-related aspects in chronic myeloid leukemia (CML) have not been studied well. We therefore analyzed 856 patients with Ph/BCR-ABL-positive CML from the German randomized CML-studies I (interferon alpha (IFN) vs hydroxyurea (HU) vs busulfan) and II (IFN+HU vs HU alone). The median observation time was 8.6 years. A total of 503 patients (59%) were male. Female patients were older (51 vs 46 years; P<0.0001), presented with lower hemoglobin (11.7 vs 12.5 g/dl; P<0.0001), higher platelet counts (459 vs 355 x 10(9)/l; P<0.0001), smaller spleen size (3 vs 4 cm below costal margin; P=0.0097), a lower rate of additional cytogenetic aberrations (9 vs 15%; P=0.018) and a less favorable risk profile (P=0.036). The transplantation rate was 14% for female (n=48) and 22% for male patients (n=113). Median survival was longer in female patients (58 vs 49 months; P=0.035) mainly attributable to better survival in the low- and intermediate-risk groups and, independent from risk groups, in the HU group. These results were confirmed by matched-pair analyses based on German population data (n=496, 59 vs 45 months; P=0.0006). This is the first analysis of gender aspects in CML using randomized trials. It demonstrates the relevance of analyses of gender differences in CML and in malignant disease at large.

Adult↗

Centrosome aberrations in chronic myeloid leukemia correlate with stage of disease and chromosomal instability.

Centrosome abnormalities are hallmarks of various cancers and have been implicated in chromosome missegregation, chromosomal instability, and aneuploidy. Since genetic instability is a common feature in chronic myeloid leukemia (CML), we sought to investigate whether centrosome aberrations occur and correlate with disease stage and cytogenetic findings in CML. We examined 34 CML samples including CD 34+Ph+cells of 18 newly diagnosed patients (chronic phase (CP)) and 16 blast crisis (BC) specimens by using a centrosome-specific antibody to pericentrin. All CP and BC samples displayed centrosome alterations as compared with corresponding CD 34+control cells. Centrosome abnormalities were detected in 29.1+/-5.9% of CP blasts and in 54.3+/-4.8% of BC blasts, but in only 2.4+/-1.1% of controls (P<0.0001). Additional karyotypic alterations to the t(9;22) translocation were found in only 1/18 CML-CP patients. In contrast, 11/16 (73%) CML-BC patients displayed additional karyotype alterations in 48.7% of analyzed cells, correlating with an abnormal centrosome status (P=0.0005). Our results indicate that centrosome defects are a common and early detectable feature in CML that may contribute to acquisition of chromosomal aberrations and aneuploidy. They may be considered as the driving force of disease progression and could serve as future prognostic markers.

Adolescent↗

Induction of centrosome and chromosome aberrations by imatinib in vitro.

Imatinib (STI571, Gleevec/Glivec) is a potent selective tyrosine kinase inhibitor and is used successfully in the treatment of chronic myeloid leukemia (CML). While karyotype alterations, in addition to the Philadelphia chromosome, are a common phenomenon of progressing CML, the observation of BCR-ABL-negative leukemic clones with distinct aberrant karyotypes under an imatinib regimen is not yet understood. Here we test the hypothesis that such tumor clones may be induced de novo from normal cells by imatinib. In vitro experiments with varying drug concentrations (5-20 microM) were performed on normal human dermal fibroblasts (NHDF), Chinese hamster embryonal and Indian muntjak fibroblasts. After 3 weeks of treatment, analysis of cell cultures by centrosome immunostaining and conventional cytogenetics revealed that imatinib induced centrosome and chromosome aberrations in all cultures in a significant dose-dependent and species-independent manner. Moreover, the results of NHDF long-term culture experiments demonstrated that aberrant phenotypes, emerging under imatinib treatment for 12 weeks, were not reversible after prolonged propagation omitting the drug. These observations suggest a causative role of imatinib in the origin of centrosome and karyotype aberrations (genetic instability) and thus may explain the emergence of clonal chromosomal abnormalities in BCR-ABL-negative progenitor cells under imatinib therapy.

Animals↗

[The competence network "acute and chronic leukemias"].

Leukemias are a challenge and a cost factor to society because of their frequency in all age groups. They also serve as a model for a variety of diseases and possess exemplary relevance for basic research and patient care. Leukemia research and therapy have achieved high standards and even a leading position in Germany with regard to clinical trials, standardization of diagnostics and molecular studies of prognostic factors, signal transduction and gene expression. Progress is hampered, however, by fragmentation of leukemia trial groups, diagnostic approaches and treatment research activities. A network was therefore created to integrate the leading leukemia trial groups on chronic myeloid leukemia (CML), acute myeloid leukemia (AML), acute lymphatic leukemia (ALL), myelodysplastic syndromes (MDS) and chronic myeloproliferative diseases (CMPD) and their interdisciplinary partners (diagnostics, treatment research, biometry) in cooperation with basic research and pharmaceutical industry to foster advancements in leukemia-related research and health care through clinical trials, promotion of translational research, introduction of standards for diagnostics and therapy, and development of evidence-based guidelines. Achievements include establishment of central information, communication and management structures, creation of an AML intergroup comprising five study groups, formation of a myelodysplastic syndromes study group and establishment of platforms for diagnostics, genomics and proteomics, and medical informatics. Exchange of scientific progress is mediated by intra- and internet, bi-annual newsletters, regular project group meetings and annual network symposia. Already now, the network structures leukemia therapy and research in Germany and supports the spread of scientific excellence in the field of leukemias.

Acute Disease↗

[Therapy of chronic myelogenous leukemia in 2004].

Chronic myelogenous leukemia constitutes a clinical model for other neoplastic diseases. The cytogenetic hallmark of CML, the Ph chromosome with the molecular juxtaposition of BCR and ABL genes and the multistep pathogenesis with the stable chronic phase, the accelerated phase and the terminal blast crisis provide the background for the translation of molecular-cytogenetic findings into clinical practice. The systematic development of the selective BCR-ABL inhibitor imatinib was based on the discovery of the molecular pathogenesis of CML. Promising preclinical data were confirmed in phase I-III trials. Concerning hematologic and cytogenetic response and adverse effects imatinib is superior to interferon alpha. Open questions are treatment duration in patients with good response, long term side effects, persistence of minimal residual disease in almost all patients, development of resistance after long term therapy, and the efficacy of combination treatments. Prospective clinical trials, e. g. CML study IV of the German CML Study Group, should answer these questions. The impact of the various treatment modalities (imatinib, interferon alpha, ara-C, allogeneic stem cell transplantation) will be elucidated. The recruitment of newly diagnosed CML patients into CML-study IV is recommended.

Antineoplastic Agents↗

Capecitabine in combination with mitomycin C in patients with gastrointestinal cancer: results of an extended multicentre phase-I trial.

The aim of this study was to determine the dose-limiting toxicity (DLT) and establish the recommended dose for mitomycin C added every 3 weeks to the standard combination dose of capecitabine. Cohorts of at least three patients with pretreated gastrointestinal carcinoma received capecitabine 1000 mg m(-2) orally twice daily on days 1-14 plus i.v. bolus mitomycin C on day 1 at doses of 4, 6, 8 or 10 mg m(-2) (corresponding to dose levels I-IV). Cycles were repeated every 3 weeks. Two treatment cycles were considered for the evaluation of DLTs. Of the 53 patients enrolled, the majority had colorectal (n=27) or gastric (n=14) cancers. Patients had received a median of two lines of prior chemotherapy (34% with >/=3 lines and 87% with prior 5-FU-based therapy). At the recommended dose level (IV, n=30), grade 3 adverse events during cycles 1 and 2 were: anaemia (10%); leukopenia (3%); thrombocytopenia (3%); stomatitis/mucositis (3%); hand-foot syndrome (3%). Two patients experienced DLTs (mucositis, n=1; neutropenic fever, n=1), but there were no grade 4 events. The median dose intensity for capecitabine and mitomycin C was 100% during cycles 1 and 2 and only four patients required postponement of therapy. Of the 43 patients evaluable for efficacy, seven achieved partial and minor remissions (16%; 95% CI, 5-28%), and 12 patients (28%) had stable disease. The favourable safety profile and promising activity of the capecitabine/mitomycin C combination, even in heavily pretreated patients, warrant further evaluation in patients with advanced colorectal and gastric cancers.

Adult↗

Pegylated liposomal doxorubicin in combination with mitomycin C, infusional 5-fluorouracil and sodium folinic acid. A phase-I-study in patients with upper gastrointestinal cancer.

Mitomycin C (MMC) in combination with infusional 5-fluorouracil (FU) plus folinic acid (FA) is an effective treatment for metastatic gastrointestinal cancer. Anthracyclines are commonly used in the treatment of upper gastrointestinal cancer. The aim of this study was to determine the maximum tolerated dose of liposomal, pegylated doxorubicin (Caelyx) in combination with infusional 5-FU/sodium FA and MMC. Escalating doses of Caelyx (15-25-30-35 mg m(-2) corresponding to dose levels I-IV) were applied on days 1 and 29, given to fixed doses of 24-h 5-FU (2000 mg m(-2)) and sodium FA (500 mg m(-2), mixed with 5-FU in one pump) weekly for 6 weeks, and MMC 7 mg m(-2) on days 8 and 36. At least three patients were treated at each dose level. A total of 25 patients are evaluable. No dose-limiting toxicity (DLT) was observed on level I (n=3). On level II, DLT occurred in three out of five patients (mucositis and leucopenia). Owing to the early DLTs at this dose, we added a 20 mg m(-2) Caelyx dose level (Ia). In total, 17 patients were treated at this dose level. Among these, only two patients experienced DLT in cycle one and 37 complete cycles have been administered in association with a low toxicity profile. The median dose intensity was 100% for each drug during the first course and no treatment delay exceeding 7 days was required. The recommended dose of 4-weekly Caelyx in combination with weekly 24-h 5-FU/sodium FA and 4-weekly MMC is 20 mg m(-2). Preliminary antitumour activity has been observed in patients with pretreated pancreatic cancer and in untreated gastric cancer.

Adenocarcinoma↗

[Clinical research in the "acute and chronic leukemias"competence network ].

Goal of the network is the construction of an exemplary cooperative leukemia network for the improvement of medical care and of health related research in acute and chronic leukemias. This is achieved by improved mechanisms of cooperation among all major groups in Germany that deal with the leukemias in research and in patient care. In practice, cooperation between clinical groups and scientists in research institutes is mediated by various instruments that improve communication, flow of information and interdisciplinary cooperation and also increase information transfer from top research institutions to clinical translation. The network comprises more than 1400 participants in about 400 university centers, large community hospitals and specialty practices with functional communication structures, interdisciplinary cooperation and nation-wide logistics. The improved cooperation and the accelerated information transfer from the bench to the "bedside" results in an added value that ultimately results in improved survival results of patients and in superior competitiveness of involved research workers and clinicians. Sustainability is addressed by establishing a leukemia foundation to support long term financial coverage of the network and by negotiating a proposal for a European Network of Excellence against leukemia within the Sixth Framework Programme of the European Union.

Acute Disease↗

Modern diagnostics in chronic myeloproliferative diseases (CMPDs).

According to the new WHO classification a group of chronic myeloproliferative diseases (CMPDs) were defined: chronic myeloid leukemia (CML), chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia and hypereosinophilic syndrome (CEL/HES), polycythemia vera (PV), chronic idiopathic myelofibrosis (with extramedullary hematopoiesis, CIMF), essential thrombocythemia (ET), and so called CMPD/unclassifiable. As clinical features and laboratory findings differ widely between these diseases several diagnostic approaches are mandatory at diagnosis for classification and are needed also for follow up studies, especially for the measurement of minimal residual disease (MRD). We here outline the laboratory set up at diagnosis and during follow up in CMPDs with specific focus on the respective therapeutical consequences. Only by using a comprehensive diagnostic panel including cytomorphology, cytogenetics, and molecular genetic methods establishing the correct diagnosis, optimizing treatment as well as evaluating treatment response is possible in CMPDs today.

Blood Cell Count↗