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Biomedical subjects

W Hiddemann

Publications and source records attributed to W Hiddemann.

At least 289 records · Page 16Linked to original sources
PubMed1995

Pharmacokinetics of Ara-CMP-Stearate (YNK01): phase I study of the oral Ara-C derivative.

Ara-CMP-Stearate (1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate, YNK 01, Fosteabine) is the orally applicable prodrug of cytosine-arabinoside (Ara-C). During a phase I study in patients with advanced low-grade non-Hodgkin lymphomas or acute myeloid leukemia, the pharmacokinetic parameters of Ara-CMP-Stearate (kindly provided by ASTA Medica, Frankfurt, Germany) were determined by HPLC analysis. Seventy-two hours after a first starting dose which served for the determination of baseline pharmacokinetic parameters, Ara-CMP-Stearate was administered over 14 days by daily oral application. Ara-CMP-Stearate was started at a dose of 100 mg/day and was escalated in subsequent patients to 200 mg/day and 300 mg/day. Plasma and urine concentrations of Ara-CMP-Stearate, Ara-C and Ara-U were measured during the initial treatment phase and within 72 h after the end of the 14-day treatment cycle. So far six patients have been treated with 100 mg/day, three with 200 mg/day and another six with 300 mg/day. One patient was treated consecutively with 100 mg, 300 mg and 600 mg. Fitting the results of the plasma concentration measurements of Ara-CMP-Stearate to a one-compartment model, the following pharmacokinetic parameters were obtained (average and variation coefficient VC). Ara-CMP-Stearate dose-independent parameters: lag time = 1.04 h (0.57); tmax = 5.72 h (0.30); t1/2 = 9.4 h (0.36). Dose-dependent parameters: at 100 mg: AUC = 1099 ng/h/ml (0.31); concentration(max) = 53.8 ng/ml (0.28); at 200 mg: AUC = 2753 ng/h/ml (0.32); concentration(max) = 154.8 ng/ml (0.46); at 300 mg: AUC = 2940 ng/h/ml (0.66); concentration(max) = 160.0 ng/ml (0.59). The long lag time and late tmax can be explained by resorption in the distal part of the small intestine. No Ara-CMP-Stearate was detected in urine samples (limit of detection = 500 pg/ml). Pharmacokinetic parameters of Ara-C following Ara-CMP-Stearate application showed the following characteristics: t1/2 = 24.3 h (0.39); AUC (100 mg) = 262 ng/h/ml (0.93); AUC (200 mg) = 502 ng/h/ml (0.87); AUC (300 mg) = 898 ng/h/ml (1.07). Since Ara-CMP-Stearate causes intravascular hemolysis after intravenous administration, it was not possible to determine its bioavailability by comparing the AUC after oral and i.v. application. Instead, the renal elimination of Ara-U, as the main metabolite of Ara-C was measured during the first 72-h period and after the last application.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1995

Identification and structural analysis of rearranged immunoglobulin heavy chain genes in lymphomas and leukemias.

The third complementarity determining region (CDR3) of the hypervariable domain of immunoglobulin heavy chain (IgH) genes represents a highly variable and clone-specific IgH-CDR3 sequences in 10 non-Hodgkin's lymphomas (NHL), five chronic lymphocytic leukemias (CLL) and five acute lymphoblastic leukemias (ALL) of B cell lineage. The IgH-CDR3 sequences were amplified using DNA extracted from clinical specimens (bone marrow, peripheral blood and fresh-frozen or paraffin-embedded lymph nodes) by a semi-nested PCR with consensus primers directed to conserved regions within the variable (VH) and the joining (JH) gene segments. In 17/20 samples (85%), a distinct IgH-CDR3 PCR product was obtained. Individual PCR products were sequenced after cloning. The nucleotide sequences of 134 randomly chosen recombinant vectors were determined demonstrating in 17/20 cases (85%) monoclonal VH-N-DH-N-JH junctions. Analysis of PCR products by temperature-gradient gel electrophoresis (TGGE) confirmed the specificity of the IgH-CDR3 PCR/sequencing results. Moreover, the combination of PCR/TGGE technology allowed the rapid and specific characterization of clonal IgH-CDR3 junctions in B cell proliferations by direct sequencing even in the presence of admixed polyclonal B cells.

Base Sequence↗
PubMed1995

Use of UITma DNA polymerase improves the PCR detection of rearranged immunoglobulin heavy chain CDR3 junctions.

The development of rapid PCR protocols for amplification of rearranged IgH gene sequences has greatly facilitated the identification of clonal IGH rearrangements in non-Hodgkin's lymphomas (NHL) and leukemias. However, the 15-35% incidence of false negative results with this approach has been a constant and unresolved problem. To assess the reliability of a previously published framework region 3 (FR3A) IgH-CDR3-PCR for detection of monoclonal IgH gene rearrangements we compared the PCR and Southern results in a series of 44 NHL and leukemias of B cell lineage showing a JH-rearrangement in Southern analysis with genomic DNA and hybridization with a IgH joining region (JH) probe. IgH-CDR3 regions were amplified using DNA extracted from clinical specimens by PCR using fluorescent dye-labeled consensus primers homologous to conserved regions within the variable (VH) and the joining (JH) gene segments. The PCR products were size separated on a high resolution polyacrylamide gel and analyzed for clonality by exact size determination and fluorescence quantification in an automated DNA sequencer. With commonly used DNA polymerases monoclonal IgH-CDR3 junctions were identified in 36/44 samples (82%). However, in the remaining eight cases (18%) with pathohistologically clearly demonstrated B cell malignancies which were also monoclonal on JH-Southern analysis, monoclonality could be demonstrated by FR3A-IgH-CDR3-PCR only with the proofreading UITma DNA polymerase. In four of these monoclonal VH--N--DH--N--JH junctions sequence analysis was performed which showed a point mutation in one and a single nucleotide deletion at the 3' terminus of the primer target site in the other case. In the remaining two cases no primer mismatches could be identified. Thus we conclude that the marked improvement of the PCR-detection rate of monoclonal IgH-CDR3 junctions was achieved at least in part due to the ability of UITma DNA polymerase to remove mismatched bases at the 3' terminus of the primers with respect to the target during the first amplification cycles. Our results suggest, that UITma is the DNA polymerase of choice for amplification of IgH-CDR3 junctions with consensus FR3A-VH- and JH-primers.

Base Sequence↗
PubMed1995

Short technical reports. Quantification of ribozyme-mediated RNA cleavage using silver-stained polyacrylamide gels.

A very sensitive, nonradioactive method for the detection of ribozymes, targets for ribozyme cleavage and cleavage products with subsequent densitometric quantification of RNA, has been developed. Amounts as low as 15 ng--corresponding to 0.16 pmol of a 300-nucleotide RNA molecule--can be visualized in denaturating polyacrylamide (PA) gels. This sensitive method allows analysis and quantification of ribozyme-mediated cleavage of in vitro-transcribed short stretches of RNA. The substitution of N'N'-methylene bisacrylamide by piperazine diacrylamide in the PA gels to improve signal-to-noise ratio could not further optimize the contrast. Sensitivity was dependent on the presence of urea in the gel and could be increased 4-fold in a gel without urea.

Densitometry↗
PubMed1994

Chemotherapy in 998 unselected childhood acute lymphoblastic leukemia patients. Results and conclusions of the multicenter trial ALL-BFM 86.

In trial ALL-BFM 86, the largest multicenter trial of the Berlin-Frankfurt-Münster (BFM) study group for childhood acute lymphoblastic leukemia (ALL), treatment response was used as an overriding stratification factor for the first time. In the previous trial ALL-BFM 83, the in vivo response to initial prednisone treatment was evaluated prospectively. A blast cell count of > or = 1,000/microL peripheral blood after a 7-day exposure to prednisone and one intrathecal dose of methotrexate (MTX) identified 10% of the patients as having a significantly worse prognosis. In trial ALL-BFM 86 patients with > or = 1,000/microL blood blasts on day 8 were included in an experimental branch EG. Patients with < 1,000/microL blood blasts on day 8 were stratified by their leukemic cell burden into two branches, Standard Risk Group (SRG) and Risk Group (RG). SRG patients received an eight-drug induction followed by consolidation protocol M (6-mercaptopurine, high-dose [HD] MTX 4 x 5 g/m2) and maintenance. RG patients were treated with an additional eight-drug reinduction element. For EG patients protocol M was replaced by protocol E (prednisone, HD-MTX, HD-cytarabine, ifosfamide, mitoxantrone). All patients received intrathecal MTX therapy; only those of branches RG and EG received cranial irradiation. In branch RG, patients were randomized to receive or not to receive late intensification (prednisone, vindesine, teniposide, ifosfamide, HD-cytarabine) in the 13th month. During the trial reinduction therapy was introduced in branch SRG, because in the follow-up of trial ALL-BFM 83 the randomized low-risk patients receiving reinduction did significantly better. Nine hundred ninety-eight evaluable patients were enrolled, 28.6% in SRG, 61.1% in RG, 10.3% in EG. At a median follow-up of 5.0 (range 3.4 to 6.9) years, the estimated 6-year event-free survival was 72% +/- 2% for the study population, 58% +/- 5% in branch SRG for the first 110 patients without reinduction therapy, 87% +/- 3% for the next 175 patients with reinduction therapy, 75% +/- 2% in branch RG, and 48% +/- 5% in branch EG. Late intensification did not significantly affect treatment outcome of RG patients; however, only 23% of the eligible patients were randomized. Prednisone poor response remained a negative prognostic parameter despite intensified therapy. The results confirmed the benefit of intensive reinduction therapy even for low-risk patients. The strategy of induction, consolidation, and intensive reinduction may offer roughly 75% of unselected childhood ALL patients the chance for an event-free survival.

Adolescent↗
PubMed1994

Characterization of clone-specific rearrangement T-cell receptor gamma-chain genes in lymphomas and leukemias by the polymerase chain reaction and DNA sequencing.

The structures of rearranged gamma-chain T-cell antigen receptor (TCR) genes were analyzed in 5 cases of T-cell acute lymphoblastic leukemia (T-ALL), in 15 cases of peripheral T-cell non-Hodgkin's lymphoma (T-NHL), in 1 case with large granular CD8 lymphocytosis, 1 case with CD8 lymphocytosis after autologous bone marrow transplantation for Hodgkin's disease, and in 2 cases with nonneoplastic diseases. Rearranged V-J TCR gamma-gene segments were amplified by the polymerase chain reaction (PCR). Because most of the biopsy tissue or bone marrow samples contained significant amounts of admixed nonmalignant T-cells, direct DNA sequencing of the PCR products yielded mixed sequence data because of coamplification of clonal together with polyclonal TCR gamma V-N-J junctions. Reliable data could only be obtained by cloning the V gamma-J gamma PCR products and sequencing several (4 to 10) randomly chosen clones. In the polyclonal samples, all PCR-derived clones differed in their specific V-N-J junctions, as expected. In the two T-cell lines and in most of the T-cell malignancies, monoclonal PCR products could be identified by the demonstration of clonally restricted V-N-J junctions. In most cases, this information yielded the desired clone-specific sequence and showed a background population of polyclonal TCR gamma cells in each specimen, except for those that were obtained from the T-ALL samples, the cell lines, or the NHL samples with high tumor cell fraction. The results obtained by PCR-directed sequencing were confirmed by temperature-gradient gel electrophoresis (TGGE) that showed distinct DNA bands only with the PCR products containing predominant (ie, monoclonal) TCR gamma V-N-J junctions. By combined sequence and TGGE analysis, it was found that PCR/TGGE is able to distinguish between monoclonal and polyclonal TCR gamma-PCR products. This finding prompted us to complete the analysis of the TCR gamma locus in the samples by PCR/TGGE using primer mixes which covered all possible V gamma and J gamma recombinations. Monoclonality was shown with all mixes by PCR/TGGE in 21 of 24 (87%) of the lymphoproliferations. In summary, the present study shows that the combination of amplifying TCR gamma V-N-J junctions by PCR with the identification of clonal PCR products by TGGE and DNA sequencing is a reliable method for the characterization of clonal TCR gamma sequences.

Base Sequence↗
PubMed1994

Pulmonary infiltrations in febrile patients with neutropenia. Risk factors and outcome under empirical antimicrobial therapy in a randomized multicenter study.

BACKGROUND: Different empirical approaches to antimicrobial treatment of lung infiltrates in patients with neutropenia were studied within a prospective, randomized multicenter trial. METHODS: Patients with neutropenia with hematologic malignancies and fever of 38.5 degrees C or higher associated with newly diagnosed lung infiltrates were randomized for an initial therapy with acylaminopenicillin plus aminoglycoside (Group A), third-generation cephalosporin plus aminoglycoside (Group B), or the double beta-lactam combination (Group C), each in combination with rifampin. Nonresponders were given empirical amphotericin B plus 5-fluorocytosine beginning on day 4, day 5, or day 6 under study. RESULTS: Of 295 patients entered, 91.2% were evaluable. Complete response was obtained in 61.3% with no significant difference between treatment groups. The addition of rifampin did not improve treatment results. Only 27.1% of patients achieved a complete response by antibiotic therapy without additional antifungal therapy. Fungi dominated in cases of microbiologically documented infections and were associated with a poorer outcome compared with bacterial pneumonias. The trend of leukocyte counts under study had a highly significant effect on the outcome of infection. CONCLUSIONS: Lung infiltrates in febrile patients with neutropenia represent a high risk of treatment failure. Persistent neutropenia has a significantly adverse effect on the outcome of infection. Incorporation of systemic antifungal agents into first-line therapy, particularly in selected high-risk subgroups, might improve future treatment results. The quality of diagnostic techniques to establish the etiology of pulmonary infiltrates needs to be improved.

Adolescent↗
PubMed1994

[Empirical antimicrobial therapy in neutropenic patients. Results of a multicenter study by the Infections in Hematology Study Group of the Paul Ehrlich Society].

BACKGROUND: Severe infections are the predominant cause of treatment failure in patients with high grade malignant hematological disorders undergoing intensive chemotherapy. PATIENTS AND METHODS: In a multicenter trial of the Paul Ehrlich Society (PEG) study group, febrile neutropenic patients with acute leukemias or other high grade hematological malignancies were randomized for a three phase sequential antimicrobial intervention comparing different widely applied regimes for empirical therapy. Patients with clinically documented infections were treated according to a modification depending on the respective source of infection, whereas in patients with microbiologically documented infections, treatment could be adapted to the sesceptibility patterns of detected pathogens. Criteria for evaluation as well as time points for response assessment and treatment escalation were strictly prescribed by the study protocol. RESULTS: Of 1573 evaluable patients, 50.9% had fever of unknown origin (FUO) throughout the study period, 17.1% had lung infiltrates, 14.1% primary bacteremia or fungemia (B/F), 12.6% other clinically documented (CDI) and 5.3% other clinically as well as microbiologically documented infections (CMDI). Cumulative response rate (CR) in patients with FUO was 91.3%, a significant difference between various regimens could not be detected in either of the three treatment phases. Patients with lung infiltrates had a significantly worse treatment outcome as compared to patients with other documented infections or with FUO (61.3% vs 82.9% vs 91.3%). Gram-positive pathogens dominated in case of microbiologically documented infections (MDI), whereas the proportion of fungal infections increased dramatically in MDI with pathogens detected only after more than six days under study. Of numerous prognostic factors analyzed, only the trend in white blood cell counts had a significant impact on treatment outcome. CONCLUSION: Infection-related mortality in neutropenic patients with high grade hematological malignancies can be markedly reduced by a systematically escalating interventional antimicrobial therapy. Early systemic antifungal treatment, especially in patients with lung infiltrates, might further improve treatment results.

Adolescent↗
PubMed1994

Proliferation of human leukemic pre-B cells induced by human bone marrow stromal cells and murine fibroblasts.

Aim of the study was the establishment of a standardized in vitro culture system for studies on proliferation and differentiation of human leukemic pre-B cells. Coincubation with human stromal cells led to a significantly higher proliferation of the cytokine-sensitive leukemic pre-B cell line BLIN-1. Clones from the murine fibroblast cell line L929 provided identical results. Coincubation with the murine cells also resulted in a significantly higher numbers of viable cells in 5 of 8 patient samples with newly diagnosed B lineage ALL. The results show that in vitro bone marrow stromal cells can be substituted by murine fibroblasts and form the basis for a simpler and more reproducible assay system.

Animals↗
PubMed1994

Interventional antimicrobial therapy in febrile neutropenic patients. Study Group of the Paul Ehrlich Society for Chemotherapy.

In this prospective multicenter trial, treatment strategies for 1573 patients with neutropenia < 1000/microliters and fever > or = 38.5 degrees C after cytotoxic chemotherapy were compared. Patients with unexplained fever were randomized to a three-phase sequential study for different established drug regimens. If an infection could be defined microbiologically or clinically, treatment modifications were determined. In phase I, treatment for all patients consisted of acylaminopenicillin (PEN) plus aminoglycoside (AMG); or third-generation cephalosporin (CEPH) plus AMG; or PEN plus CEPH. In 800 patients with unexplained fever the response rates were: PEN/AMG (n = 258): 74.4%, CEPH/AMG (n = 252): 73.4%; PEN/CEPH (n = 290): 70.0%. Total response rate was 72.5%. In phase II, patients not responding after 3 days received PEN/CEPH/vancomycin (n = 70) or PEN/CEPH/AMG (n = 74). The respective response rates were 52.9% and 55.4%, total 54.2%. If fever did not resolve, the patients received either PEN/CEPH (n = 40) or imipenem/cilastatin (n = 59) both in combination with amphotericin-B/5-flucytosin/rifampin. The response rates were 62.5% and 79.7%, respectively (p = 0.07), total 72.7%. No significant differences between the treatment modalities compared were found. Analyzing all three phases together, 91.3% of patients with unexplained fever were cured. The response rate was also analyzed according to patients with gram-positive bacteremia (n = 183), response rate = 82.5%; gram-negative organisms (n = 145) 78.6%; fungemia (n = 51) 43.1% (p < 0.001); lung infiltrates (n = 269) 61.3% (p < 0.001); clinically documented infections (n = 198) 84.4%; and clinically and microbiologically documented infections (n = 84) 82.1%. If infections were diagnosed after at least 5 febrile days, more lung infiltrates and fungal infections occurred (p < 0.001). Leukocytes rising above 500/mu during the infection predicted better response rates (p < 0.001): in unexplained fever 97.8% vs 86.5% and lower death rates 1.5% vs 8.5%. In documented infections the response rates were then 89.9% vs 62.3% and the death rates 7.0% vs 20.5%. Therapy of neutropenic fever and infections must be adapted according to risk factors and should include early empiric antifungal therapy. The therapeutic and prophylactic use of hematopoietic growth factors to overcome neutropenia should be evaluated.

Adolescent↗
PubMed1994

Current status and future perspectives in the treatment of low-grade non-Hodgkin's lymphomas.

Low-grade non-Hodgkin lymphomas (NHL) comprise a heterogeneous group of disorders both in terms of their cellular and histological composition as well as in terms of their clinical course. The most usually applied classification systems, the Working Formulation and the Kiel classification as well as the recently proposed Revised European American Lymphoma classification, discriminate between low-, intermediate- and high-grade subtypes. In general, low-grade NHL are characterized by a low to moderate proliferative activity and a long clinical course with median survival times ranging from approximately 3 years for centrocytic (CC) or mantle-cell lymphomas (MCL) to 5-8 years for centroblastic-centrocytic (CB-CC) or follicular lymphomas (FL). Recent cytogenetic and molecular biologic analyses indicate that these differences may result from distinct genetic abnormalities such as the translocation t(14;18), which is frequently observed in FL-NHL and is associated with a bcl-2 overexpression and inhibition of apoptosis, or the deregulation of PRAD1 in MCL-NHL induced by the translocation t(11;14). Therapy of low-grade lymphomas depends mainly on the extent of the disease. In the early stages I and II, at which approximately 15 to 20% of low-grade NHL are diagnosed, radiotherapy may be applied with curative intention. The treatment of patients with more advanced stages III and IV is controversial. The currently available information justifies a conservative approach of observing the natural course of the disease until therapeutic intervention is required due to the occurrence of B-symptoms, hematopoietic insufficiency or lymphoma progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Fludarabine in the management of malignant lymphomas.

Fludarabine has revealed significant single agent activity in non-Hodgkin's lymphomas (NHL) in a variety of clinical phase I/II studies. Its efficacy appears most pronounced in low grade NHL and the follicular subtype in particular as well as in Waldenström's macroglobulinaemia. In these disorders, response rates range from 31 to 67% in previously treated patients, and up to 75% in previously untreated patients. Intermediate and high grade NHL subtypes, as well as Hodgkin's disease and lymphomas of the T-cell lineage, appear less responsive. Further improvement may result from combination therapy such as the fludarabine, mitoxantrone, dexamethasone regimen. Prospective controlled clinical trials are needed to compare fludarabine with standard therapies and to define the most appropriate place for this highly promising agent in the treatment of malignant lymphomas.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

New perspectives in the treatment of acute myeloid leukemia by hematopoietic growth factors.

The application of hematopoietic growth factors in the treatment on acute myeloid leukemia (AML) may principally aim at shortening the period of treatment associated neutropenia and reducing the rate of infectious complications by their post-therapeutic administration but may also be used to increase the sensitivity of leukemic blasts to antileukemic therapy by pretherapeutic growth stimulation. Both aspects were addressed in subsequent clinical phase II studies and preclinical investigations. In a first clinical trial, 36 patients with high-risk AML received granulocyte-macrophage colony-stimulating factor (GM-CSF) after successful cytoreductive chemotherapy and experienced a shortening of the period of post-therapeutic neutropenia by 6 to 9 days, leading to a significant reduction of treatment-associated deaths from 39% to 14%. In preclinical studies an enhancement of the cytotoxicity of cytosine arabinoside (AraC) on leukemic blasts could be shown by pretreatment with GM-CSF or IL-3. Investigations on the impact of hematopoietic growth factors on the intracellular metabolism of AraC indicated that this effect was primarily mediated by an increase in the activity of DNA-polymerase-alpha. The evaluation of different doses of AraC showed the most marked increase after the combination of GM-CSF with conventional rather than high doses of AraC. Based on these preclinical experiments, a prospective randomized trial was subsequently initiated investigating the effect of GM-CSF before and during induction, consolidation, and the first two cycles of maintenance chemotherapy in newly diagnosed AML. This ongoing trial has enrolled 67 patients at the current time. An early interim analysis showed no differences in remission rates but a tendency toward a longer remission duration in patients receiving GM-CSF. These data indicate that hematopoietic growth factors like GM-CSF in particular may provide a new perspective in the treatment of acute myeloid leukemia with the possibility of reducing treatment associated mortality and perhaps of increasing the efficacy of antileukemic treatment.

Acute Disease↗
PubMed1994

Experimental basis for the use of recombinant human granulocyte-macrophage colony-stimulating factor in patients with acute myeloid leukemia.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) not only stimulates hematopoiesis, but also induces the proliferation and differentiation of leukemic myeloid cells. The observation that clonogenic growth of malignant cells can be induced in vitro has led to the development of therapeutic concepts that aim to increase the sensitivity of cells to cytostatic and cytotoxic agents by priming them with GM-CSF. In in vitro experiments, preincubating leukemic cells with recombinant cytokines including GM-CSF led to a consistent, dose-dependent increase in the cytotoxicity of cytosine arabinoside (Ara-C). This effect has since been observed in patients with acute myeloid leukemia (AML) although its mechanism is not yet entirely clear. It seems that GM-CSF increases the relative number of cells in the S phase of the cell cycle and enhances the activity of DNA polymerases, enzymes that are essential to nucleotide incorporation into DNA. Based on these experimental results, numerous clinical trials have investigated the role of GM-CSF in priming leukemic blasts before chemotherapy. These studies will allow us to determine whether our in vitro observations of increased cytotoxicity translate into higher remission rates and durations, and will help us to identify the patient subgroups most likely to benefit from this therapeutic approach.

Acute Disease↗