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Biomedical subjects

Martin Zimmermann

Publications and source records attributed to Martin Zimmermann.

33 records · Page 2Linked to original sources
PubMed2005

Insulin-like growth factor binding protein-2 at diagnosis of childhood acute lymphoblastic leukemia and the prediction of relapse risk.

Despite remarkable advances in the clinical outcome of most children with acute lymphoblastic leukemia, a substantial number of patients ultimately relapse or suffer from side effects of treatment. In the present study, we investigated components of the IGF system for their predictive value to identify patients with an increased risk of relapse. Serum levels of IGF-I, IGF-II, IGF binding protein (IGFBP)-1, IGFBP-2, and IGFBP-3 were measured in 162 children with acute lymphoblastic leukemia treated by the Berlin Frankfurt Munster Study Group. At diagnosis we found elevated IGFBP-2, low IGFBP-3, low IGF-I, and low normal IGF-II, but normal IGFBP-1 levels. Highly elevated IGFBP-2 and low IGFBP-3 at the time of diagnosis correlated with a higher risk of an event such as lack of remission or a relapse. Serum IGFBP-2 was identified as an independent factor that adds additional information for the prediction of events (relapse or treatment failure) to the conventional prognostic factors such as white blood cell count and platelet count at diagnosis.

Adolescent↗
PubMed2005

Osteonecrosis: a treatment related toxicity in childhood acute lymphoblastic leukemia (ALL)--experiences from trial ALL-BFM 95.

BACKGROUND: Osteonecrosis (ON) as a complication during treatment of acute lymphoblastic leukemia (ALL) has gained rising attention over the past decade. Corticosteroids, representing an essential element of antileukemic therapy, are known to induce ON, which in turn may cause significant morbidity. Due to spontaneous reporting of affected patients with ON, a group-wide evaluation was performed to determine incidence, risk factors, and morbidity for ON. PROCEDURE: Patients were identified via spontaneous reporting to the study center and via questionnaire, addressing all 64 participating centers. We retrospectively analyzed 1,951 patients below 18 years of age who were treated according to trial ALL-BFM 95 between 01.01.1996 and 30.06.2000. RESULTS: Thirty-one patients (14 male, 17 female) affected by ON were identified. The overall 5-year cumulative incidence for ON is 1.8%. The incidence for patients <10 years is 0.2%, whereas for patients >/=10 years it is 8.9% (P = 0.00) and 16.7% (P = 0.003) for patients >/=15 years. The majority (n = 20) showed ON in two or more joints, and the joints most commonly affected were knees (14 patients, 24 affected knees) and hips (11 patients, 20 affected joints). Thirteen out of 31 patients had to undergo surgery in the course of their disease. CONCLUSIONS: Symptomatic ON is a rare event in patients treated with BFM-type chemotherapy with an overall 5-year cumulative incidence of 1.8%. The age group >/=10 years, and particularly adolescents >/=15 years have a significantly higher risk of developing ON.

Adolescent↗
PubMed2005

Modeling and optimization of high-sensitivity, low-volume microfluidic-based surface immunoassays.

Microfluidics are emerging as a promising technology for miniaturizing biological assays for applications in diagnostics and research in life sciences because they enable the parallel analysis of multiple analytes with economy of samples and in short time. We have previously developed microfluidic networks for surface immunoassays where antibodies that are immobilized on one wall of a microchannel capture analytes flowing in the microchannel. This technology is capable of detecting analytes with picomolar sensitivity and from sub-microliter volume of sample within 45 min. This paper presents the theoretical modeling of these immunoassays where a finite difference algorithm is applied to delineate the role of the transport of analyte molecules in the microchannel (convection and diffusion), the kinetics of binding between the analyte and the capture antibodies, and the surface density of the capture antibody on the assay. The model shows that assays can be greatly optimized by varying the flow velocity of the solution of analyte in the microchannels. The model also shows how much the analyte-antibody binding constant and the surface density of the capture antibodies influence the performance of the assay. We then derive strategies to optimize assays toward maximal sensitivity, minimal sample volume requirement or fast performance, which we think will allow further development of microfluidic networks for immunoassay applications.

Antigen-Antibody Complex↗
PubMed2005

Proliferation characteristics in pediatric Hodgkin's lymphoma point to a cell cycle arrest in the G(1) phase.

This study was undertaken to determine the prognostic relevance of the proliferation rate in neoplastic cells in children and adolescents with Hodgkin's lymphoma. Paraffin-embedded biopsy specimens were immunostained with the proliferation-associated monoclonal antibodies Ki-S5 (Ki-67 antigen) and Ki-S2 (which detects the repp86 protein). Repp86 is a protein of about 100 kDa encoded by a gene located on human chromosome band 20q11.2. In contrast to the Ki-67 antigen, repp86 expression is restricted to the cell cycle phases G(2), S and M. Immunohistochemical results on diagnostic lymph node biopsy specimens from 224 patients included in two pediatric multicenter Hodgkin's trials, GPOH HD-90 and HD-95, were compared with clinical data. High Ki-67 antigen expression was a striking feature of Hodgkin's and Reed-Sternberg cells as well as lymphocytic and histiocytic cells (median: 80%, range: 20-100%), in contrast to low repp86 expression (median: 20%, range: 10-80%; P<0.001). The proliferation rate was independent of histological subtype, stage and presence of B symptoms. The probability of event-free and overall survival (+/-standard error) of all patients at 5 years was 91.6+/-2.0 and 98.1+/-1.0%, respectively. The proliferation rate of tumor cells did not influence the outcome. The difference between Ki-67 and repp86 expression in Hodgkin's and Reed-Sternberg or lymphocytic and histiocytic cells points to a possible cell cycle arrest in the G(1) phase, which may explain the obvious paradox of a highly proliferating but slowly growing paucicellular tumor. High Ki-67 expression does not seem to be an adverse prognostic factor in pediatric and adolescent patients with Hodgkin's lymphoma treated by effective risk-adapted chemo-radiotherapy regimens.

Adolescent↗
PubMed2005

The impact of age and gender on biology, clinical features and treatment outcome of non-Hodgkin lymphoma in childhood and adolescence.

We analysed the impact of age and gender on biology and outcome of 2084 patients diagnosed with non-Hodgkin lymphoma (NHL) between October 1986 and December 2002 and treated according to the Berlin-Frankfurt-Münster (BFM) multicentre protocols NHL-BFM-86, -90 and -95. Median age at diagnosis was 8.0 years for 97 precursor B-lymphoblastic lymphoma (pB-LBL) patients, 8.8 years for 335 T-lymphoblastic lymphoma (T-LBL) patients, 8.4 years for 1004 Burkitt's lymphoma/leukaemia (BL/B-AL) patients, 11.4 years for 173 diffuse large B-cell lymphoma (centroblastic subtype) (DLBCL-CB) patients, 13.2 years for 40 primary mediastinal large B-cell lymphoma (PMLBL) patients and 10.8 years for 215 anaplastic large-cell lymphoma (ALCL) patients (P < 0.00001). The male:female ratio was 0.9:1 for pB-LBL and PMLBL, 1.7:1 for DLBCL-CB, 1.8:1 for ALCL, 2.5:1 for T-LBL and 4.5:1 for BL/B-AL (P < 0.00001). The probability of event-free survival at 5 years (5-year pEFS) was 85 +/- 1% for all 2084 patients [median follow-up 5.7 (0.1-15.9) years], and was significantly superior for male T-LBL and DLBCL-CB patients. Comparing age-groups 0-4, 5-9, 10-14 and 15-18 years, pEFS was inferior for the youngest patients only in the pB-LBL- and ALCL-groups. T-LBL and DLBCL-CB adolescent females had worse outcome than younger girls while age had no impact on pEFS for boys. We conclude that the distribution of age and gender differed between NHL-subtypes. The impact of gender on outcome differed between NHL subgroups. The prognostic impact of age differed not only by NHL-subtype but also according to gender in some subtypes.

Adolescent↗
PubMed2004

Early deaths and treatment-related mortality in children undergoing therapy for acute myeloid leukemia: analysis of the multicenter clinical trials AML-BFM 93 and AML-BFM 98.

PURPOSE: The rates of early death (ED) and treatment-related mortality (TRM) are unacceptably high in children undergoing intensive chemotherapy for acute myeloid leukemia (AML). Better strategies of supportive care might help to improve overall survival in these children. PATIENTS AND METHODS: In a retrospective study, we analyzed incidence, clinical features, and risk factors for lethal complications of 901 children enrolled onto the multicenter trials Acute Myeloid Leukemia-Berlin-Frankfurt-Muenster (AML-BFM) 93 and AML-BFM 98. RESULTS: One hundred four patients (11.5%) enrolled onto the clinical trials AML-BFM 93 and AML-BFM 98 died shortly after diagnosis or as a result of treatment-related complications. Thirty-two patients (3.5%) died before (six patients) or during (26 patients) the first 14 days of treatment, mainly as a result of bleeding or leukostasis. Low performance status, hyperleukocytosis, and French-American-British type M5 were the main risk factors for a lethal event before day 15. After day 15, the predominant causes of death were complications caused by infections, particularly bacterial and fungal infections. The incidence of lethal infections was highest during induction therapy and decreased thereafter. When comparing both clinical trials, significantly fewer patients died within the first 6 weeks in AML-BFM 98 than in AML-BFM 93 (14 [3.5%] of 430 patients v 35 [7.4%] of 471 patients; P = .01). CONCLUSION: To reduce the high incidence of ED and TRM in children with AML, early diagnosis and adequate treatment of complications are needed. Children with AML should be treated in specialized pediatric cancer centers only. Prophylactic and therapeutic regimens for better treatment management of bleeding disorders and infectious complications have to be assessed in future trials to ultimately improve overall survival in children with AML.

Adolescent↗
PubMed2004

The impact of the methotrexate administration schedule and dose in the treatment of children and adolescents with B-cell neoplasms: a report of the BFM Group Study NHL-BFM95.

In the Non-Hodgkin Lymphoma-Berlin-Frankfurt-Münster 95 (NHL-BFM95) study, we tested by randomization whether for patients with B-cell neoplasms methotrexate as intravenous infusion over 4 hours (MTX-4h) is not inferior to, but less toxic than, a 24-hour intravenous infusion (MTX-24h). Second, we investigated against the historical control of study NHL-BFM90, whether for patients with moderate tumor mass MTX can be reduced from 5 g/m(2) to 1 g/m(2). Patients received 2 5-day therapy courses in risk group R1 (resected), 4 in R2 (lactate dehydrogenase [LDH] < 500 U/L), 5 in R3 (LDH > 500 to < 1000 U/L) and 6 in R4 (LDH > 1000 U/L and/or central nervous system [CNS] disease). Courses contained MTX 1 g/m(2) in R1 + R2 and 5 g/m(2) in R3 + R4. Of 505 patients (April 1996 to March 2001), 364 were randomized to receive MTX-4h or MTX-24h. Failure-free survival (pFFS, 1 year) for arm MTX-4h versus MTX-24h, respectively, was 95% +/- 5% (n = 20) versus 100% (n = 19) in R1, 94% +/- 2% (n = 88) versus 96% +/- 2% (n = 95) in R2, and 77% +/- 5% (n = 62) versus 93% +/- 3% (n = 69) in R3 +/- R4 (per-protocol analysis). Incidence of mucositis grade III/IV was significantly lower with MTX-4h in all risk groups. For patients in R2, event-free survival (pEFS) was 95% +/- 2% (n = 222) in NHL-BFM95 (MTX 1 g/m(2)) and 97% +/- 1% (n = 154) in NHL-BFM90 (MTX 5 g/m(2)). In conclusion, MTX-4h was less toxic than MTX-24h. MTX-4h was noninferior to MTX-24h for limited stage B-cell non-Hodgkin lymphoma (B-NHL) but not for advanced disease. For limited disease, MTX 1 g/m(2) is noninferior to 5 g/m(2).

Adolescent↗
PubMed2003

FLT3 internal tandem duplication in 234 children with acute myeloid leukemia: prognostic significance and relation to cellular drug resistance.

FLT3 is a receptor tyrosine kinase involved in the proliferation and differentiation of hematopoietic stem cells. FLT3 internal tandem duplications (FLT3/ITDs) are reported in acute myeloid leukemia (AML) and predict poor clinical outcome. We found FLT3/ITDs in 11.5% of 234 children with de novo AML. FLT3/ITD-positive patients were significantly older and had higher percentages of normal cytogenetic findings or French-American-British (FAB) classification M1/M2 and lower percentages of 11q23 abnormalities or FAB M5. FLT3/ITD-positive patients had lower remission induction rates (70% vs 88%; P =.01) and lower 5-year probability rates of event-free survival (pEF) (29% vs 46%; P =.0046) and overall survival (32% vs 58%; P =.037). Patients with high ratios (higher than the median) between mutant and wild-type FLT3 had significantly worse 2-year EFS rates than FLT3/ITD-negative patients (pEFS 20% vs 61%; P =.037), whereas patients with ratios lower than the median did not (pEFS 44% vs 61%; P =.26). FLT3/ITD was the strongest independent predictor for pEFS, with an increase in relative risk for an event of 1.92 (P =.01). Using an MTT (methyl-thiazol-tetrazolium)-based assay, we studied cellular drug resistance on 15 FLT3/ITD-positive and 125 FLT3/ITD-negative AML samples, but we found no differences in cellular drug resistance that could explain the poor outcomes in FLT3/ITD-positive patients. We conclude that FLT3/ITD is less common in pediatric than in adult AML. FLT3/ITD is a strong and independent adverse prognostic factor, and high ratios between mutant and WT-FLT3 further compromise prognosis. However, poor outcomes in FLT3/ITD-positive patients could not be attributed to increased in vitro cellular drug resistance.

Acute Disease↗
PubMed2003

The glutathione synthetase of Schizosaccharomyces pombe is synthesized as a homodimer but retains full activity when present as a heterotetramer.

Glutathione synthetase was overexpressed as a histidine-tagged protein in Schizosaccharomyces pombe and purified by two-step affinity chromatography. The recovered enzyme occurred in two different forms: a homodimeric protein consisting of two identical 56-kDa subunits and a heterotetrameric protein composed of two 32-kDa and two 24-kDa subfragments. Both forms are encoded by the GSH2 gene. The 56-Da protein corresponds to the complete GSH2 open reading frame, while the subfragments are produced following the cleavage of this larger protein by a metalloprotease. A stable homodimer was obtained by site-directed mutagenesis to remove the protease cleavage site, and this showed normal activity. A structural model of the fission yeast glutathione synthetase was produced, based on the x-ray coordinates of the human enzyme. According to this model the interacting domains of the proteolytic subfragments are strongly entangled. The subfragments were therefore coexpressed as independent proteins. These subfragments assembled correctly to yield functional heterotetramers with equivalent activity to the wild type enzyme. Furthermore, a permuted version of the protein was created. This also showed normal levels of glutathione synthetase activity. These data provide novel insight into the mechanisms of protein folding and the structure and evolution of the glutathione synthetase family.

Amino Acid Sequence↗
PubMed2003

Diagnostic cerebrospinal fluid examination in children with acute lymphoblastic leukemia: significance of low leukocyte counts with blasts or traumatic lumbar puncture.

PURPOSE: To determine the significance of leukemic blasts or traumatic lumbar puncture (TLP) in diagnostic CSF of children enrolled in the Berlin-Frankfurt-Münster (BFM) Acute Lymphoblastic Leukemia-BFM-95 trial. PATIENTS AND METHODS: A total of 2,021 patients were retrospectively evaluated according to initial central nervous system (CNS) status. Patients were classified as follows: CNS1 (CNS negative, n = 1,605), CNS2 (< or = 5 WBC/ micro L CSF with blasts, n = 103), CNS3 (CNS positive, n = 58), TLP+ (TLP with blasts, n = 135), or TLP- (TLP without blasts, n = 111). Patients with CNS2 and TLP+ status were eligible for two additional doses of intrathecal (IT) methotrexate (MTX). CNS3 patients received additional IT MTX and cranial irradiation (18 Gy). RESULTS: CNS2, CNS3, and TLP+ groups contained a higher percentage of patients with unfavorable characteristics. Cox regression analysis identified TLP+ and CNS3 status as prognostically significant (CNS3): risk ratio (RR) = 2.3; 95% confidence interval [CI], 1.4 to 3.6; P =.0005; TLP+: RR = 1.5; 95% CI, 1.02 to 2.2; P =.04. Overall 5-year event-free survival (EFS) is 79%, for CNS1 it is 80%, and for TLP- it is 83%. CNS2 patients have an EFS of 80%, but the cumulative incidence of relapses with CNS involvement is higher compared with CNS1 patients (0.10 v 0.04). TLP+ patients have a significantly reduced EFS (73%, P =.003) because of an increased incidence of CNS relapses. CNS3 patients suffer from more systemic and CNS relapses (EFS 50%). CONCLUSION: CNS2 patients have the same prognosis as patients with CNS1 status, whereas the EFS of TLP+ patients is inferior to CNS1 but superior to CNS3 patients (P =.001). Both subgroups may have benefitted from additional IT MTX.

Antimetabolites, Antineoplastic↗
PubMed2002

Cellular drug resistance in childhood acute myeloid leukemia is related to chromosomal abnormalities.

Specific cytogenetic abnormalities predict prognosis in childhood acute myeloid leukemia (AML). However, it is unknown why they are predictive and whether this is related to drug resistance. We previously reported that Down syndrome (DS) AML was associated with favorable resistance profiles. Here, we successfully analyzed drug resistance and (cyto-) genetic abnormalities of 109 untreated childhood AML samples using the 4-day total cell-kill methyl-thiazolyl tetrazolium (MTT) assay. Patients were classified according to the genetic abnormalities in the leukemic cells: t(8;21), inv(16), t(15;17), t(9;11), other 11q23 translocations, abnormalities of chromosome 5/7, trisomy 8 alone, normal karyotype, single random, and multiple (defined as 2 or more) abnormalities. The DS AML samples were excluded from the subgroup analysis. Samples with chromosome 5/7 abnormalities were median 3.9-fold (P =.01) more resistant to cytarabine than other AML samples. The t(9;11) samples were more sensitive to cytarabine (median 2.9-fold, P =.002), etoposide (13.1-fold, P =.001), the anthracyclines (2.9- to 8.0-fold, P <.01), and 2-chlorodeoxyadenosine (10.0-fold, P =.002) than other AML samples. The trisomy 8 and t(15;17) groups were too small for meaningful analysis. All other genetic subgroups did not show specific resistance profiles. Overall, we found no differences in drug resistance in samples taken at diagnosis between patients remaining in continuous complete remission (CCR) versus the refractory/relapsed patients. Within several genetic subgroups, however, relapsed/refractory patients were more cytarabine resistant when compared with patients remaining in CCR, but numbers were small and the results were not significant. We conclude that some, but not all, cytogenetic subgroups in childhood AML display specific drug-resistance profiles.

Acute Disease↗
PubMed2002

Genetic polymorphisms in the tumour necrosis factor locus in childhood acute lymphoblastic leukaemia.

Genetic polymorphisms in the tumour necrosis factor (TNF) locus influence the outcome of non-Hodgkin's lymphoma (NHL). We investigated whether these polymorphisms might contribute to the clinical course of childhood acute lymphoblastic leukaemia (ALL). Genomic DNA from 214 childhood ALL patients was analysed. Patients with a high-risk haplotype were older than patients with low-risk haplotype (P = 0.024). No statistically significant associations were found between TNF haplotype and sex, WBC counts, central nervous system involvement, immunophenotype, response to chemotherapy, and event-free survival. These data suggest that genetic polymorphisms in the TNF locus have a limited effect on the outcome of childhood ALL.

Age Factors↗
PubMed2002

Polymorphisms within glutathione S-transferase genes in pediatric non-Hodgkin's lymphoma.

BACKGROUND AND OBJECTIVES: Glutathione S-transferases (GSTs) are involved in the metabolism of a number of cancer chemotherapeutic agents. Certain members within the GST superfamily exhibit phenotypically relevant genetic polymorphisms which have been associated with outcome in hematologic malignant disease. DESIGN AND METHODS: In the present study we genotyped a cohort of 169 pediatric non-Hodgkin's lymphoma (NHL) patients with available specimens from the NHL-BFM trials 86 and 90 conducted by the Berlin-Frankfurt-Münster (BFM) study group to assess a potential association of phenotypically relevant glutathione S-transferase polymorphisms (GSTM1, GSTT1, GSTP1 codon 105) with treatment outcome in this patient group. RESULTS: Treatment failure in patients with mature B-cell NHL was significantly less likely to occur in patients carrying at least one GSTM1 allele in comparison to those with a homozygous deletion of GSTM1. This protective effect mediated by the presence of GSTM1 was even more pronounced within the subset of therapy group B patients at highest clinical risk of treatment failure (B-ALL, disease stage IV, disease stage III with unresected abdominal tumor, and LDH activity > or = 500 U/L). Of all events in therapy group B, 87.5% occurred in this high risk group. Within this subset, the multivariate relative risk reached 4.98 (95% CI = 1.27-19.52; p= 0.021). INTERPRETATION AND CONCLUSIONS: Our results suggest that genetic variation at the GSTM1 locus may be of clinical importance in pediatric NHL and may be a potential candidate for indicating future treatment stratification strategies.

Adolescent↗