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J Krauter

Publications and source records attributed to J Krauter.

At least 19 recordsLinked to original sources
PubMed2006

siRNA-mediated AML1/MTG8 depletion affects differentiation and proliferation-associated gene expression in t(8;21)-positive cell lines and primary AML blasts.

The chromosomal translocation t(8;21) is associated with 10-15% of all cases of acute myeloid leukaemia (AML). The resultant fusion protein AML1/MTG8 interferes with haematopoietic gene expression and is an important regulator of leukaemogenesis. We studied the effects of small interfering RNA (siRNA)-mediated AML1/MTG8 depletion on global gene expression in t(8;21)-positive leukaemic cell lines and in primary AML blasts using cDNA arrays, oligonucleotide arrays and real-time reverse transcription-polymerase chain reaction (RT-PCR). Suppression of AML1/MTG8 results in the increased expression of genes associated with myeloid differentiation, such as AZU1, BPI, CTSG, LYZ and RNASE2 as well as of antiproliferative genes such as IGFBP7, MS4A3 and SLA both in blasts and in cell lines. Furthermore, expression levels of several genes affiliated with drug resistance or indicative of poor prognosis AML (BAALC, CD34, PRG2, TSPAN7) are affected by AML1/MTG8 depletion. In conclusion, siRNA-mediated suppression of AML1/MTG8 cause very similar changes in gene expression pattern in t(8;21)-positive cell lines and in primary AML blasts. Furthermore, the results suggest that the specific targeting of AML1/MTG8 function may be a promising approach for complementing existing treatment strategies.

Acute Disease↗
PubMed2005

Weekly 24 h infusion of aviscumine (rViscumin): a phase I study in patients with solid tumours.

Aviscumine is a ribosome-inactivating protein with potent antitumour activity in vitro and in vivo and is an Escherichia coli-derived recombinant counterpart of natural mistletoe lectin-I. The current study was performed to determine the safety profile, dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) of a prolonged infusion of aviscumine in cancer patients. Aviscumine was given once weekly as a 24 h central intravenous infusion in patients with advanced, refractory progressive solid malignant tumours. Fourteen fully eligible patients (11 male, 3 female) with a median age 58 yrs (range 41-77) were enrolled. They had histologically verified disease, were 18 yrs old, had an ECOG PS 2 and adequate bone marrow, liver and renal function. DLT was defined as any non-haematological grade 3-4 toxicity (Common Toxicity Criteria [CTC] version 2.0), neutrophil count <500/ microl for 7 days, febrile neutropenia or thrombocytopenia grade 4. The MTD was defined as the dose level below the dose at which 2 patients per dose level experienced a DLT during the first treatment cycle. Colorectal cancer, soft tissue sarcoma and pancreatic cancer were the most common tumour types. Dose levels of aviscumine ranged from 4 to 6 microg/kg. The median number of cycles was 2.8 (range, 2-8). Common side effects in cycle 1 were fatigue, fever, nocturia, urticaria, erythema and pruritus. DLTs occurred in 2/3 patients on the 6 microg/kg dose level and consisted of increases in ASAT grade 3, ALAT grade 3, gammaGT grade 3/4, hypokalemia grade 3 and fatigue grade 3. No DLTs were observed on dose levels 4 and 5 microg/kg. The best response (RECIST) was stable disease in 4 pts, lasting for 4-8 cycles. Pharmacokinetics indicated that potentially active plasma levels of the compound were maintained during the entire infusion. We conclude that the recommended dose for weekly 24 h infusions of Aviscumine should be 5 microg/kg.

Adult↗
PubMed2004

Individual patient data-based meta-analysis of patients aged 16 to 60 years with core binding factor acute myeloid leukemia: a survey of the German Acute Myeloid Leukemia Intergroup.

PURPOSE: To evaluate prognostic factors for relapse-free survival (RFS) and overall survival (OS) and to assess the impact of different postremission therapies in adult patients with core binding factor (CBF) acute myeloid leukemias (AML). PATIENTS AND METHODS: Individual patient data-based meta-analysis was performed on 392 adults (median age, 42 years; range, 16 to 60 years) with CBF AML (t(8;21), n = 191; inv(16), n = 201) treated between 1993 and 2002 in prospective German AML treatment trials. RESULTS: RFS was 60% and 58% and OS was 65% and 74% in the t(8;21) and inv(16) groups after 3 years, respectively. For postremission therapy, intention-to-treat analysis revealed no difference between intensive chemotherapy and autologous transplantation in the t(8;21) group and between chemotherapy, autologous, and allogeneic transplantation in the inv(16) group. In the t(8;21) group, significant prognostic variables for longer RFS and OS were lower WBC and higher platelet counts; loss of the Y chromosome in male patients was prognostic for shorter OS. In the inv(16) group, trisomy 22 was a significant prognostic variable for longer RFS. For patients who experienced relapse, second complete remission rate was significantly lower in patients with t(8;21), resulting in a significantly inferior survival duration after relapse compared with patients with inv(16). CONCLUSION: We provide novel prognostic factors for CBF AML and show that patients with t(8;21) who experience relapse have an inferior survival duration.

Acute Disease↗
PubMed2004

Risk-adapted induction and consolidation therapy in adults with de novo AML aged </= 60 years: results of a prospective multicenter trial.

We treated 305 de novo acute myeloid leukemia (AML) patients aged </=60 years with risk-adapted therapy. Patients with CBF leukemias or normal karyotype and good response to induction I [</=5% bone marrow (BM) blasts on day 15] were considered standard risk (SR), all others as high risk (HR). Patients with t(15;17) were excluded. Chemotherapy comprised double induction followed by early consolidation. As late consolidation, SR patients received high-dose cytarabine/daunorubicin (AraC/DNR). SR patients with normal karyotype were allotransplanted from HLA-matched siblings. HR patients were allotransplanted or if no sibling donor was available autotransplanted with peripheral blood progenitor cells (PBSC) harvested after early consolidation. 89% of the SR and 60% of the HR patients achieved CR. The continuous complete remission (CCR) rate at 80 months (median follow-up: 48 months) was 48% for SR and 32% for HR. The CCR rate was 54% for t(8;21), 47% for normal karyotype, and 33% for inv(16) patients. In the HR group, the CCR rate did not differ significantly for patients with bad response to IVA-I, unfavorable karyotype, or both. Forty-five HR patients were autotransplanted (n=20) or allotransplanted (n=25). The probability of CCR was 44% for autotransplantation vs 33% for allotransplantation. In conclusion, our risk-adapted strategy produced encouraging results in SR patients. Early response to therapy is a strong prognostic factor that predicts the probability of CR and long-term outcome.

Adolescent↗
PubMed2003

The emergence of a C/EBPalpha mutation in the clonal evolution of MDS towards secondary AML.

Recently, mutations in the transcription factor CCAAT/ enhancer binding protein alpha (C/EBPalpha) have been described in acute myeloid leukemia (AML). We performed a mutational analysis of the C/EBPalpha gene in the myelodysplastic syndromes and AML with antecedent MDS. No mutations were found in patients with refractory anemia (0/27), refractory anemia with ringed sideroblasts (0/7), refractory anemia with excess of blasts (RAEB 0/16) or chronic myelomonocytic leukemia (CMML 0/5). One out of 13 patients with RAEB-T/AML secondary to MDS showed a mutation in the C/EBPalpha gene. In this patient a 4 bp insertion disrupted codon 69 in one allele. This novel +1 frame shift is predicted to result in a truncated protein of 107 amino acids. However, the dominant protein translated was the C/EBPalpha isoform p30, which was previously shown to inhibit the DNA-binding and transactivation properties of C/EBPalpha p42. Interestingly this mutation could not be detected at diagnosis in the initial RAEB and RAEB-T stage. The mutation appeared at relapse after chemotherapy for RAEB-T. We conclude that the C/EBPalpha mutation was not essential for the initial blast accumulation. The emergence of a bast clone carrying a C/EBPalpha mutation at relapse indicates that this mutation may confer a growth advantage in a myeloid cell with an established differentiation block.

Adult↗
PubMed2002

Central venous catheter infections in patients with acute leukemia.

BACKGROUND: Central venous catheters (CVCs) have become an essential tool for an appropriate management of patients with acute leukemia. Infectious complications are a major concern in patients treated for acute leukemia. Although CVC-related infections are considered to be a major source of infections during neutropenia (<500/microl), data regarding the incidence of CVC-related infections are rare in acute leukemia. PATIENTS AND METHODS: We analyzed nontunneled CVCs in 58 patients with acute leukemia (22 men/36 women) in 119 chemotherapy cycles from April 1996 to January 1998 in a prospective trial. Proven CVC-related infection was defined as the isolation of the same organism from peripheral blood and CVC tip. CVC infection was suspected or possible when exit site inflammation and positive blood culture or organisms typical for CVC infection were observed. RESULTS: Mean neutropenia/cycle was 16.3 days (SD 8.0). 178 CVCs with 2,576 CVC days (mean 14.5 days, SD 7.2 days) were used in 119 cycles. Fever occurred in 87 cycles (73%). Blood stream infection was proven in 31 out of 87 febrile episodes (26.1%) with 40 isolates (8 gram-negative, 31 gram-positive, 1 Candida spp.). Colonization of the CVC tip was observed in 24 CVC lines with 28 isolates (27 gram-positive, 1 gram-negative); however, proven CVC-related infections were observed in 5 episodes only, all with coagulase-negative staphylococci. In another 6 episodes, CVC-related infection was assumed (local inflammation and gram-positive blood culture). Six further episodes had typical blood isolates (4 coagulase-negative staphylococci, 1 Candida spp.) and were considered possible CVC-related infections. In none of the remaining afebrile 32 cycles was a CVC infection observed or suspected. CONCLUSION: Gram-positive organisms contributed to the majority of CVC-related infections (16 out 17 CVC infections); however, the overall incidence of CVC infections in acute leukemia patients was 6.5/1,000 CVC days only (1.9 proven/2.3 suspected/2.3 possible/1,000 CVC days).

Adult↗
PubMed2001

Detection and quantification of CBFB/MYH11 fusion transcripts in patients with inv(16)-positive acute myeloblastic leukemia by real-time RT-PCR.

We used a newly established real-time RT-PCR assay for the quantification of the leukemia-specific CBFB/MYH11 transcripts in inv(16)-positive acute myeloblastic leukemia. CBFB/MYH11 could be quantified over a five log range, with a detection limit of 10 molecules of a CBFB/MYH11 plasmid and a 1:10(5) dilution of RNA of the inv(16)-positive ME-1 cell line, respectively. The fusion transcripts were also quantified in 19 patients with acute myeloblastic leukemia and an inv(16) at initial diagnosis. The expression of CBFB/MYH11 varied over a two log range without correlation to clinical response or relapse rate. In nine patients, CBFB/MYH11 was also quantified during/after chemotherapy and autologous or allogeneic stem cell transplantation. All of these patients showed a similar decline of CBFB/MYH11 after intensive therapy. Six of these patients are in complete remission with a stable low-level or absent CBFB/MYH11 expression. Three patients relapsed, and their CBFB/MYH11 transcripts rose again to pretreatment levels. In two patients, this increase in CBFB/MYH11 could be detected by real-time PCR before hematological relapse. These data indicate that real-time RT-PCR can be used for the sensitive detection and quantification of CBFB/MYH11 transcripts in the follow-up of patients with inv(16)-positive AML.

Chromosome Inversion↗
PubMed2001

Cleavage of AML1/MTG8 by asymmetric hammerhead ribozymes.

The chromosomal translocation t(8;21) is one of the most frequent aberrations associated with acute myeloid leukaemia. It joins the 5' section of the AML1 gene with the almost complete open reading frame of MTG8 (ETO). The resulting fusion RNA represents a leukaemia-specific target for antisense/ribozyme inhibition. We tested several asymmetric hammerhead ribozymes targeted against the fusion site for their ability to cleave the AML1/MTG8 RNA at low magnesium concentrations. One ribozyme cleaves AML1/MTG8 RNA with high catalytic efficiency without binding or cleaving the wild-type AML1 transcript. The presence of cellular RNA does not affect the cleavage. Injection of AML1/MTG8 RNA and ribozyme RNA into Xenopus eggs or oocytes causes a specific reduction of AML1/MTG8 protein expression. Asymmetric anti-AML1/MTG8 ribozymes may be valuable modulators of AML1/MTG8 expression in leukaemic cells.

Animals↗
PubMed2001

Receptor-mediated endocytosis of CD34 on hematopoietic cells after stimulation with the monoclonal antibody anti-HPCA-1.

CD34 most probably acts as a receptor molecule on hematopoietic progenitor cells; however, its precise function remains to be elucidated. To track the intracellular pathway of CD34 after binding of a stimulatory antibody (anti-HPCA-1), immuno-electron microscopical analysis was performed on cells of normal bone marrow (NBMPC), acute leukemias, and the KG1a cell line. Before stimulation, CD34 was evenly distributed over the cell surface. After binding of the anti-HPCA-1, but not the anti-HPCA-2 antibody to CD34 and labeling with 30-nm immunogold, a rapid capping of CD34 and a subsequent internalization from the cell surface via clathrin-coated pits and coated vesicles was observed. The percentage of internalized CD34/immunogold complexes ranged from 8 to 80% in the NBMPC and the leukemic blasts, whereas KG1a cells showed an internalization rate of only 0.42%. Moreover, in the KG1a cells, the CD34/immunogold complexes were not associated with the coated pits. These differences in CD34 internalization did not correlate to the mRNA expression for the full-length or truncated CD34 assessed by isotype-specific real-time PCR. Taken together, evidence was found that CD34 is a surface receptor molecule that is modulated by receptor-mediated endocytosis. CD34 on KG1a cells appears to have a functional and/or structural defect, preventing modulation of this epitope.

Acute Disease↗
PubMed2000

Immunoelectron microscopic analysis of CD 54 surface distribution and its role in homotypic interaction on normal monocytes and blasts of acute myeloid leukemia.

The role of CD 54 in the homotypic interaction of normal monocytes and the blasts of five cases of acute myeloid leukemia (AML) was analyzed by immunoelectron microscopy (IEM). The cells were seeded on glass coverslips precoated with an electrontransparent melamine resin, which allowed their in situ labeling with monoclonal antibodies (MoAb) and subsequent analysis by whole mount immunoelectron microscopy (WM-IEM) or transmission immunoelectron microscopy (TIEM). Timed incubation of the cells in serum-free medium +/- interferon-gamma (IFN-gamma, 500 U/ml) induced a spreading of the monocytes and the blasts of four out of five leukemias, characterized by the development of numerous filopodia which led to initial cell-cell contacts. In parallel, an increase in CD 54 surface density in four out of five leukemias could be detected, while no evidence of a CD 54 redistribution (capping) on single cells could be observed. WM-IEM studies detected no CD 54 molecules in the "early" cell-cell contacts, while "later" cell-cell contacts displayed strong CD 54 positivity. These data indicate that CD 54 is not involved in initial cell-cell contacts but is shifted secondarily to the cell contact sides and may thereby stabilize the adjacent membrane areas. The absence of spreading of the CD 54 negative blasts in one out of five leukemias and the blockade of the cellular migration by an anti-CD 54 MoAb (Clone 84H10) in the remaining cases suggest that CD 54 expression is necessary for cellular locomotion. The observed inhibitory effect of the anti-CD 54 MoAb probably mimics a negative circuit that serves to control cellular migration.

Acute Disease↗
PubMed2000

Comparison of nested competitive RT-PCR and real-time RT-PCR for the detection and quantification of AML1/MTG8 fusion transcripts in t(8;21) positive acute myelogenous leukemia.

The chromosomal translocation t(8;21)(q22;q22) is one of the most frequent karyotypic aberrations in acute myeloid leukemia (AML) and results in a chimeric fusion transcript AML1/MTG8. Since AML1/MTG8 fusion transcripts remain detectable by RT-PCR in t(8;21) AML patients in long-term hematological remission, quantitative assessment of AML1/MTG8 transcripts is necessary for the monitoring of minimal residual disease (MRD) in these patients. Competitive RT-PCR and recently real-time RT-PCR are increasingly used for detection and quantification of leukemia specific fusion transcripts. For the direct comparison of both methods we cloned a 42 bp DNA fragment into the original AML1/MTG8 sequence. The resulting molecule was used as an internal competitor for our novel competitive nested RT-PCR for AML1/MTG8 and as an external standard for the generation of AML1/MTG8 standard curves in a real-time PCR assay. Using this standard molecule for both PCR techniques, we compared their sensitivity, linearity and reproducibility. Both methods were comparable with regard to all parameters tested irrespective of analyzing serial dilutions of plasmids, cell lines or samples from t(8;21) positive AML patients at different stages of the disease. Therefore, both techniques can be recommended for the monitoring of MRD in these particular AML patients. However, the automatization of the real-time PCR technique offers some technical advantages.

Chromosomes, Human, Pair 21↗
PubMed1999

Association between structural and numerical chromosomal aberrations in acute myeloblastic leukemia: a study by RT-PCR and FISH in 447 patients with de-novo AML.

We analyzed 447 patients with de novo AML using alpha-satellite probes for the chromosomes 7, 8, X, and Y and RT-PCR for t(8;21), t(15;17) and inv(16). In 130/447 patients (29%) chromosomal aberrations were found. Thirty-three patients (7%) had a t(8;21); 11 of these had the additional loss of a sex chromosome (p<0.001) and two a trisomy 8. Twenty-nine patients (6%) had a t(15;17); four of these had a trisomy 8. Sixteen patients (4%) displayed an inv(16); four of these had a trisomy 8. Twenty-two patients (5%) had a sole trisomy 8 and one patient the combination of trisomy 8 and trisomy X. Five patients (1%) displayed the loss of a Y-chromosome as the sole abnormality and two patients had a sole trisomy X. In 22 patients (5%) a monosomy 7 was found, and in none of these patients were additional chromosomal aberrations detected by RT-PCR (p < 0.05). In conclusion, trisomy 8 and the loss of a gonosome are frequently associated with structural chromosomal aberrations with a significant association of -X/Y and t(8;21). The absence of these genomic lesions in AMLs with monosomy 7 suggests that the monosomy 7 has a specific role in the development of these leukemias and their clinical course.

Adolescent↗
PubMed1999

Real-time RT-PCR for the detection and quantification of AML1/MTG8 fusion transcripts in t(8;21)-positive AML patients.

AML1/MTG8 was quantified relative to the expression of the GAPDH housekeeping gene by real-time RT-PCR in 22 patients with t(8;21)-positive acute myeloblastic leukaemia (AML) at initial diagnosis and in seven of these patients also during/after chemotherapy and allogeneic bone marrow transplantation. Real-time PCR was able to specifically detect and quantify AML1/MTG8 over a 5 log range. The detection limit for t(8;21)-positive cells was a dilution of 1:105. The AML1/MTG8 expression varied considerably among the 22 AML patients at intial diagnosis with a ratio AML1/MTG8:GAPDH of 0.5135+/-0.536 (range 0.1-2.14, median 0.318). In six patients with t(8;21)-positive AML a marked decline of AML1/MTG8 could be induced by chemotherapy. These patients are in ongoing complete haematological remission (CR) with a constant low-level AML1/MTG8 expression. In another patient a rapid rise of AML1/MTG8 transcripts could be detected in CR after allogeneic bone marrow transplantation and the patient relapsed 10 weeks later. In conclusion, real-time RT-PCR is a suitable approach for the quantification of AML1/MTG8 transcripts in the monitoring of AML patients with t(8;21) during/after chemotherapy and can provide data of prognostic relevance.

Chromosomes, Human, Pair 21↗
PubMed1999

Myelodysplastic syndrome with monosomy 7 after immunosuppressive therapy in Behçet's disease.

Only few cases of Behçet's and hematological malignancies have been reported until now. We recently observed a 39-year-old female patient with Behçet's disease developing a myelodysplastic syndrome (MDS) FAB subtype refractory anemia with excess of blasts in transformation [RAEB-t] with a monosomy 7 after being treated with cyclosporin A and chlorambucil for several years. This case is reported and the occurrence of hematological malignancies and Behçet's disease is reviewed.

Adult↗
PubMed1998

Effect of stimulation by interferon gamma and tumor necrosis factor alpha on CD54 expression and homotypic aggregation of blasts of acute lymphoblastic leukemias.

CD54 (intercellular adhesion molecule-1, ICAM-1) surface expression on the blasts in ten cases of acute lymphoblastic leukemia (ALL) and its up-regulation by human recombinant interferon-gamma (IFNgamma) and/or tumor necrosis factor-alpha (TNFalpha) were studied in a serum-free culture system. In addition, the function of CD54 was assessed by a cellular aggregation assay. Prior to in vitro culture, only 3/10 ALL cases had more than 20% CD54-positive blasts. A 24-h incubation in serum-free medium alone induced CD54 positivity in another two cases. In these two ALLs, stimulation with IFNgamma and/or TNFalpha further enhanced CD54 positivity. In addition, TNFalpha induced CD54 expression in one further case. In the remaining four cases no CD54 expression was induced by either cytokine. Of the six cases with constitutive or inducible CD54 expression, only five displayed CD54-dependent cellular aggregation. Taken together, the ALLs studied were heterogeneous with respect to their constitutive and cytokine-driven CD54 expression, while TNFalpha seemed to be more effective than IFNgamma. In most cases, the CD54 molecule was functionally active, in that CD54 expression was paralleled by CD54-dependent homotypic aggregation of the blasts.

Adolescent↗
PubMed1998

Effect of topical oral G-CSF on oral mucositis: a randomised placebo-controlled trial.

Oral mucositis is a dose-limiting toxicity of intensive chemotherapy. It is caused directly by the cytotoxic effect of chemotherapeutic agents and indirectly by sustained neutropenia. Severe oral mucositis is an important predisposing factor for life-threatening septic complications during aplasia. It also reduces quality of life. At present, no effective causal prophylaxis or treatment against oral mucositis is established. We performed a prospective randomised placebo-controlled trial using topical oral r-metHuG-CSF (filgrastim) in high-grade lymphoma patients treated according to the B-NHL protocol, which contains high-dose methotrexate and causes severe oral mucositis (WHO grades I-IV) in >50% of patients. Between August 1996 and July 1997, a total of 32 chemotherapy cycles were documented in eight patients (four male, four female). Mucosal erythema and ulceration were recorded. All patients assessed their oral pain and impact on swallowing daily, using a subjective scale from no to maximal discomfort (1-10). In addition, oral mucositis was assessed according to the WHO score. Filgrastim was administered in 16 cycles as a viscous mouthrinse (carboxymethylcellulose 2%, oleum citrii) 4 x 120 microg/day from days 10 to 16. Sixteen cycles were given to control patients, of these 14 with placebo, and another two cycles with no treatment. Severe mucositis (WHO grade III/IV) was documented in 21 of 32 cycles (65.5%). A difference of borderline significance was observed for the reduction of maximum severity of oral mucositis between G-CSF vs placebo (P = 0.058), with a reduction of WHO grade IV of 50% (four G-CSF vs eight control). The number of days in hospital was reduced significantly in the G-CSF group (P = 0.02). In conclusion, topical oral G-CSF mouthrinses may be beneficial to reduce oral mucositis.

Administration, Topical↗
PubMed1998

Detection of karyotypic aberrations in acute myeloblastic leukaemia: a prospective comparison between PCR/FISH and standard cytogenetics in 140 patients with de novo AML.

In 140 patients with de novo acute myeloid leukaemia (AML) standard cytogenetics were compared with RT-PCR for the detection of t(8;21), t(15;17) and inv(16) and fluorescence in situ hybridization (FISH) for numerical aberrations of chromosomes 7, 8, X and Y. RT-PCR detected 18 cases with t(8;21), 12 with t(15;17) and seven with inv(16). In two cases with t(8;21), two with t(15;17) and four with inv(16) these aberrations had not been detected by standard cytogenetics. There were no false negative PCR results. In 12 patients with these chromosomal changes, standard cytogenetics revealed additional chromosomal aberrations. In 16 patients sole numerical aberrations of the chromosomes 7, 8, X or Y were found by FISH. In these patients the sensitivity of FISH and standard cytogenetics was comparable. In 87 patients no aberrations could be found by PCR and FISH whereas in 24 of these patients standard cytogenetics revealed an abnormal karyotype. These data recommend the combination of standard cytogenetics and molecular techniques to improve the sensitivity for the detection of genetic lesions in AML. Once chromosomal markers have been identified by combined analysis these markers could be used to monitor residual disease during/after chemotherapy, by RT-PCR and/or FISH.

Adult↗