Biomedical subjects

W Siegert

Publications and source records attributed to W Siegert.

At least 37 records · Page 2Linked to original sources

PubMed2001

Second German consensus on immunogenetic donor search for allotransplantation of hematopoietic stem cells.

The present paper summarizes the results of the second German consensus meeting on immunogenetic donor search for allotransplantation of hematopoietic stem cells held in Essen in November 1999 under the auspices of the German Society for Immunogenetics (DGI) and the German Working Party for Blood and Marrow Transplantation (DAG-KBT). Immunogeneticists and transplant physicians from all over the country agreed to update the national standards for: (1) search strategy including the role of unrelated and extended family donor search after unsuccessful core family donor search, (2) histocompatibility loci to be typed, (3) histocompatibility typing techniques to be used (HLA serology vs DNA-based HLA typing, cellular tests, serum cross-match), and (4) acceptable HLA mismatches in the context of a defined underlying disease, donor type, and conditioning regimen.

Aging↗

PubMed2001

Salvage treatment with paclitaxel, ifosfamide, and cisplatin plus high-dose carboplatin, etoposide, and thiotepa followed by autologous stem-cell rescue in patients with relapsed or refractory germ cell cancer.

PURPOSE: To study feasibility and efficacy of a new salvage regimen in patients with relapsed and/or refractory germ cell tumors. PATIENTS AND METHODS: Between May 1995 and February 1997, 80 patients were entered onto a phase II study. Conventional-dose salvage treatment with three cycles of paclitaxel 175 mg/m(2), ifosfamide 5 x 1.2 g/m(2), and cisplatin 5 x 20 mg/m(2) (TIP) was followed by one cycle of high-dose chemotherapy (HDCT) with carboplatin 500 mg/m(2) x 3, etoposide 600 mg/m(2) x 4, and thiotepa 150 to 250 mg/m(2) x 3 (CET). In 23 patients, one additional cycle of paclitaxel 175 mg/m(2) and ifosfamide 5 g/m(2) (TI) was given immediately before TIP to improve stem-cell mobilization. RESULTS: Fifty-five (69%) of 80 patients responded to TIP, 24 (30%) of 80 patients had stable disease (n = 5) or tumor progression (n = 19), and one patient died. Only 62 (78%) of 80 patients received subsequent HDCT. Among those, 41 (66%) of 62 patients responded and 20 (32%) of 62 patients had stable disease (n = 3) or tumor progression (n = 17). One patient died after HDCT from multiorgan failure. Survival probabilities at 3 years were 30% for overall and 25% for event-free survival. Peripheral neurotoxicity with sensorimotor impairment grade 2 through 4 in 29%, paresthesias grade 2 through 4 in 24%, and skin toxicity grade 2 through 3 in 15% of patients were the most relevant side effects. CONCLUSION: Treatment with TIP followed by high-dose CET is feasible and can induce long-term remissions in 25% of patients with relapsed or refractory germ cell tumors. Peripheral nervous toxicity in approximately one third of patients is a disadvantage of this salvage strategy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

Salvage chemotherapy in relapsed germ cell tumors.

Issues concerning the optimal salvage treatment in patients with germ cell tumors are for the most part controversial. As the majority of patients will suffer systemic relapses, chemotherapy will remain the mainstay of any salvage treatment. However, the question of whether to use conventional-dose or high-dose chemotherapy (HDCT) immediately arises. Prognostic factors have recently been recognized as an aid in this decision. However, as reliable data are lacking for many clinical scenarios, the salvage treatment of germ-cell tumors continues to be a therapeutic challenge.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

Bioequivalence investigation of high-dose etoposide and etoposide phosphate in lymphoma patients.

PURPOSE: To compare etoposide pharmacokinetics following administration of high-dose etoposide and etoposide phosphate, a water-soluble prodrug of etoposide. Bioequivalence was assessed using a two-treatment randomized crossover design. METHODS: Ten patients with high-risk or relapsed lymphoma were treated with a sequential high-dose chemotherapy. They were randomized to receive either 3 x 400 mg/m2 etoposide or an equimolar amount of etoposide phosphate (as 1-h infusions on three consecutive days) in the first course and the alternative drug in the second course. Serial plasma and ultrafiltered plasma samples were collected and analysed for etoposide by a reversed-phase HPLC method with UV and electrochemical detection. Pharmacokinetic parameters were estimated using a two-compartment model. Bioequivalence was assessed calculating the 90% confidence intervals (CI) for the ratios of the geometric means of AUC(0-infinity) and additionally of Cmax of etoposide derived from etoposide phosphate relative to etoposide in plasma and ultrafiltered plasma as point estimates (level of significance alpha < 0.05). RESULTS: Pharmacokinetic parameters of etoposide were comparable in both treatment arms except that terminal half-life was significantly shorter and apparent Vss in ultrafiltered plasma was significantly larger following administration of the prodrug. The point estimates for AUC(0-infinity) of etoposide derived from etoposide phosphate relative to etoposide were 102.9% and 88.4% for plasma and ultrafiltered plasma, respectively. The 90% CIs were in the range from 80% to 125% where bioequivalence can be assumed. The point estimates of Cmax on day 3 of chemotherapy were 96.5% and 81.7% in plasma and ultrafiltrate with the 90% CI in ultrafiltered plasma being out of the range from 80% to 125%. CONCLUSION: With respect to total drug exposure, represented by AUC(0-infinity), high-dose etoposide phosphate is bioequivalent to high-dose etoposide.

Adult↗

PubMed2001

Novel T-cell receptor delta gene rearrangement involving a recombining element located 2.6 kb 3' from the Vdelta2 gene segment.

In this study, we describe a novel T-cell receptor delta (TCRdelta) gene rearrangement observed in acute myeloid leukemia with coexpression of T-lymphoid antigens (Ly+AML) and in peripheral blood leukocytes (PBL) from one out of ten healthy donors. The rearrangement was identified by Southern blot analysis using a joining region (Jdelta1) specific probe and amplified by polymerase chain reaction (PCR) with a variable region (Vdelta2) and Jdelta1 specific primers. The nucleotide sequence analysis of an atypical 3000 bp PCR product allowed localization of the breakpoint within the TCRdelta gene locus, 2.6 kb 3' from the Vdelta2 gene segment. A regular Ddelta2-Ddelta3-Jdelta1 joining was found at the 3' end of the breakpoint, indicating that the rearrangement was mediated by the VDJ recombinase, but no TCRdelta gene segment was detected at the 5' end. Analysis of the germline sequence 3' from the breakpoint revealed an isolated recombination signal sequence (RSS) capable of initiating a rearrangement. The RSS motif described by us is the second TCRdelta recombining element (deltaRec2). The deltaRec2(Ddelta)Jdelta1 recombination is a rather rare event and can be found in acute leukemia and in PBL from healthy individuals. Most likely, the nonfunctional deltaRec2(Ddelta)Jdelta1 rearrangement is a transient step during the VDJ recombination. It may potentially lead to deletion of the deltaRec2(Ddelta)Jdelta1 complex and either to direct joining of a Vdelta region to one of the downstream Jdelta regions or to a rearrangement of the TCRalpha gene.

Adult↗

PubMed2001

Assessment of amifostine as protection from chemotherapy-induced toxicities after conventional-dose and high-dose chemotherapy in patients with germ cell tumor.

BACKGROUND: We assessed the efficacy of amifostine for protection from chemotherapy-induced toxicities in patients treated with conventional-dose paclitaxel, ifosfamide, cisplatin (TIP) and high-dose carboplatin, etoposide and thiotepa (CET) followed by peripheral blood progenitor cell (PBPC) rescue. PATIENTS AND METHODS: In a prospective single-center study 40 patients with relapsed or refractory germ-cell tumors (GCT) were treated with 3 cycles of conventional-dose TIP followed by one cycle of high-dose CET. Patients were randomized either to receive one fixed dose of 500 mg amifostine per day of conventional-dose TIP and two fixed doses of 500 mg per day amifostine during high-dose CET (group A, n = 20) or no amifostine (group B, n = 20). Prior to the first cycle of TIP, one course of 175 mg/m2 paclitaxel and 5 g/m2 ifosfamide (TI) followed by granulocyte-colony stimulating factor (G-CSF) at 10 microg/kg/day were given for PBPC mobilization. RESULTS: Toxicities and response to conventional-dose TIP and high-dose CET could be evaluated in 40 patients (100%) and 32 of 40 patients (80%), respectively. Peripheral neurotoxicity (i.e. paresthesia or sensorymotor impairment), hearing impairment, hematologic toxicity, nephrotoxicity, nausea, myalgia, skin- and liver-toxicity did not differ siginificantly between the two patient groups. Likewise, the response rates to TIP and high-dose CET were comparable in patients with or without amifostine. After a median follow-up of 18 months, 8 of 20 (40%) patients of group A and 6 of 20 (30%) patients of group B are without relapse. CONCLUSION: Repeated low doses of 500 mg amifostine additional to conventional-dose TIP or high-dose CET showed no unequivocal advantage in protection from treatment-related toxicities. Furthermore, no significant differences in response rates or survival could be observed in this small number of patients.

Adult↗

PubMed2001

Four patients with AL amyloidosis treated with high-dose chemotherapy and autologous stem cell transplantation.

Four patients with AL amyloidosis underwent high-dose chemotherapy and autologous stem cell transplantation at our institutions. Here, we report the clinical courses and outcomes in these patients. Two patients with multi-organ amyloid deposits including cardiac involvement died within 12 days after high-dose chemotherapy. However, in the other two patients, one of whom was suffering from amyloid-related cardiac failure, a significant improvement of organ function was achieved.

Adult↗

PubMed2001

Skin involvement as the first manifestation of systemic aspergillosis in patients after allogeneic hematopoietic cell transplantation.

Skin involvement due to a systemic infection with Aspergillus species in the course of allogeneic hematopoietic cell transplantation is extremely rare. We report the clinical course of two patients with hematologic malignancies who underwent allogeneic hematopoietic cell transplantation (HCT) and developed disseminated skin involvement as the first clinical symptom of a proven systemic Aspergillus infection.

Adult↗

PubMed2001

A fludarabine-based dose-reduced conditioning regimen followed by allogeneic stem cell transplantation from related or unrelated donors in patients with myelodysplastic syndrome.

We investigated the feasibility and efficacy of a fludarabine-based dose-reduced conditioning regimen followed by stem cell transplantation from related (n = 5) or unrelated HLA-matched donors (n = 7) in 12 patients with high risk MDS, who were not eligible for a standard myeloablative conditioning regimen. The conditioning regimen consisted of fludarabine 30 mg/m(2) daily for 6 days, busulfan 4 mg/kg daily for 2 days and anti-thymocyte globulin (ATG, rabbit) 10 mg/kg daily for 4 days in 11 patients, while one patient received fludarabine, ATG, cyclophosphamide and thiotepa. Graft-versus-host disease prophylaxis consisted of cyclosporine and a short course of methotrexate. The median age of the patients was 53 years (range 37-59). The median percentage of blasts in bone marrow aspirate at transplantation was 15% (range <5% to 35%). Diagnosis at transplant was RA (n = 1), RAEB (n = 5), RAEB-T (n = 5) and sAML (n = 1). A complex karyotype including monosomy 7 was noted in five patients. The reasons for using a dose-reduced conditioning regimen were prior autologous/syngeneic BMT (n = 4), active fungal infection (n = 2) or age/reduced performance status (n = 6). Engraftment was observed in all patients with complete donor chimerism. The incidence of acute GVHD (grade II-IV) was 33%. Eight patients died during follow-up due to relapse (n = 4), liver toxicity (n = 2), aspergillus (n = 1) or aGVHD grade IV (n = 1). After a median follow-up of 19 months, the 2-year estimated disease-free survival is 12% (95% CI: 2-23%) and the overall survival is 26% (95% CI: 4-52%). Fludarabine dose-reduced conditioning prior to allogeneic stem cell transplantation in high risk MDS patients, who were not eligible for standard transplantation, resulted in stable engraftment with complete chimerism, but the toxicity and relapse rate were considerable.

Adult↗

PubMed2001

Dose-reduced conditioning for allografting in 44 patients with chronic myeloid leukaemia: a retrospective analysis.

This retrospective study describes the outcome of patients with chronic myeloid leukaemia after allografting using dose-reduced conditioning with fludarabine and busulphan. Forty-four Philadelphia chromosome (Ph)-positive patients were transplanted in nine German centres; 26 patients were in chronic phase, 11 in accelerated phase and seven in blast crisis. Thirty-four patients achieved complete remission, with 18 alive and disease-free at a median follow-up of 562 d (range 244-922 d). Grade II-IV acute graft-versus-host disease (GVHD) incidence was 43%. Twenty patients died, 15 of causes unrelated to relapse. Risk factors predisposing to graft failure by univariate analysis were an unrelated donor (8/23 compared with a related donor 2/21, P = 0.07) and interferon therapy within 90 d of transplant (4/6 versus 3/17, P = 0.025). At the last follow-up, of 31 patients for whom molecular or cytogenetic data were available, 16 (52%) were polymerase chain reaction-negative, and seven (23%) were Ph-negative by fluorescent in situ hybridization. These findings demonstrate that dose-reduced conditioning with fludarabine and busulphan provides durable engraftment and a low rate of relapse. However, in this population, many of whom were not eligible for high-dose conditioning due to age, reduced performance status, previous complications or extensive pre-treatment, these data highlight the need for effective anti-infectious and GVHD prophylaxis. In addition, this study supports the discontinuation of interferon therapy at least 90 d before transplant

Adult↗

PubMed2001

Quantitative detection of Toxoplasma gondii DNA in human body fluids by TaqMan polymerase chain reaction.

OBJECTIVE: A new quantitative polymerase chain reaction (real-time PCR) was designed to detect Toxoplasma DNA in human body fluid samples. METHODS: Real-time fluorescence detection of amplification product formation on the basis of the TaqMan-System was established with Toxoplasma 18S rDNA as a target gene. RESULTS: The method provides a high sensitivity comparable to conventional nested PCR procedures and generates quantitative data when detecting toxoplasmic DNA in human blood, cerebrospinal or amniotic fluid. Moreover, data were obtained investigating blood samples from an immunocompromised patient with reactivated toxoplasmosis after allogeneic bone marrow transplantation, monitoring the therapeutic effect. CONCLUSIONS: The potential application of this method to detect Toxoplasma DNA in body fluids and to follow the development of parasitemia under therapy could be demonstrated.

Animals↗

PubMed2001

PBPC mobilization with paclitaxel, ifosfamide, and G-CSF with or without amifostine: results of a prospective randomized trial.

BACKGROUND: The impact of amifostine on PBPC mobilization with paclitaxel and ifosfamide plus G-CSF was assessed. STUDY DESIGN AND METHODS: Forty patients with a median age of 34 years (range, 19-53) who had germ cell tumor were evaluated for high-dose chemotherapy. Patients were randomly assigned to receive either a single 500-mg dose of amifostine (Group A, n = 20) or no amifostine (Group B, n = 20) before mobilization chemotherapy with paclitaxel (175 mg/m(2)) given over 3 hours and ifosfamide (5 g/m(2)) given over 24 hours (TI) on Day 1. G-CSF at 10 microg per kg per day was given subsequent to TI with or without amifostine from Day 3 until the end of leukapheresis procedures. RESULTS: In 2 (10%) of 20 patients receiving amifostine and 3 (15%) of 20 patients not receiving it, no PBPC separation was performed because of mobilization failure. No significant differences were observed in the study arms with regard to the time from chemotherapy until first PBPC collection or the number of apheresis procedures needed to harvest more than 2.5 x 10(6) CD34+ cells per kg. Furthermore, leukapheresis procedures yielded comparable doses of CD34+ cells per kg (3.4 x 10(6) vs. 3.6 x 10(6); p = 0.82), MNCs per kg (2.7 x 10(8) vs. 2.6 x 10(8); p = 0.18), and CFU-GM per kg (15.9 x 10(4) vs. 19.3 x 10(4); p = 0.20). Patients in Group A had higher numbers of circulating CD34+ cells on Day 10 (103.0/microL vs. 46.8/microL; p = 0.10) and on Day 11 (63.0/microL vs.14.3/microL; p = 0.04) than did patients in Group B. CONCLUSION: Administration of a single dose of amifostine before chemotherapy with TI mobilized higher numbers of CD34 cells in the circulation, but did not enhance the overall collection efficiency in the present trial.

Adult↗

PubMed2001

Chemotherapy in patients with metastatic or relapsed germ-cell tumours.

The optimal treatment in patients with poor prognosis germ-cell tumours (GCT), according to the International Germ Cell Cancer Collaborative Group (IGCCCG) classification, and in patients with refractory or relapsed disease after cisplatin-based chemotherapy is controversial. As the majority of patients will suffer systemic relapses, chemotherapy is the mainstay of treatment. However, the question of whether or not to use conventional-dose or high-dose chemotherapy (HDCT) in these patients arises. Prognostic factors have recently been recognised to aid in this decision. However, reliable data on chemotherapy as primary treatment in poor prognosis patients and as the first-salvage attempt in patients with relapsed or refractory GCT are lacking. This report reviews the recent developments in first-line and salvage HDCT strategies and discusses the role of predictive factors for treatment outcome.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

Quantification of human cells in NOD/SCID mice by duplex real-time polymerase-chain reaction.

BACKGROUND AND OBJECTIVES: The aim of this study was the development of a fast and reliable polymerase chain reaction (PCR) assay which quantifies the proportion of human cells in immunodeficient chimeric mice, for example transplanted with human hematopoietic stem cells. DESIGN AND METHODS: We developed a TaqMan chemistry-based, real-time duplex PCR assay to quantify human and murine DNA in a single-tube reaction in parallel (HUmu PCR). Two independent sets of primers and exonuclease probes, located in the tumor necrosis factor-a gene of both species, were selected to amplify specifically human and murine genomic DNA. Serial dilutions of defined numbers of human cells in mouse cells served to construct calibration curves. The test was applied to NOD/SCID mice transplanted with CD34(+) cells isolated from human cord blood and compared to FACS analysis. RESULTS: Analysis of DNA from human cells diluted stepwise into a fixed number of murine cells - and vice versa - led to calibration curves with good correlation for human and murine cells (r(2)>0.99) with a detection limit of 2% human cells. Results obtained with the HUmu PCR paralleled those of FACS analysis. However, in contrast to FACS analysis, which requires fresh single cell suspensions, the HUmu PCR can be carried out on already stored samples, even from solid organs and, moreover, the quantity of material required for analysis is very low. INTERPRETATION AND CONCLUSIONS: The HUmu PCR presented here is the first real-time PCR assay for simultaneous quantification of human and murine cells. It is extremely fast, accurate and is an interesting alternative method for quantifying the proportion of human DNA in organs of chimeric mice.

Animals↗

PubMed2001

ICE--an efficient drug combination for stem cell mobilization and high-dose treatment of malignant lymphoma.

Between 1989 and 1999 we studied the ICE regimen in sequential trials in 290 patients with malignant lymphoma and germ-cell tumours. For patients with relapsed or refractory lymphoma we could demonstrate a comparable efficacy of ICE to other high-dose chemotherapy (HDCT) regimens but with a toxicity profile in favour of ICE. From a retrospective comparative analysis of ICE as HDCT regimen in patients with malignant lymphoma and germ-cell tumours we conclude that the characteristic toxicity profile of ICE varies depending on prior drug exposure of individual patients. Further dose intensification of ICE may be achieved with acceptable toxicity by adding further drugs (e.g. anthracyclines) or by treatment with sequential cycles of ICE (Tandem-HDCT). More convenient drug formulations (e.g. etoposide phosphate) might further improve the therapeutic index of ICE.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

A pilot study on the role of cytomegalovirus & human herpesvirus-6 infections in Indian bone marrow transplant recipients.

BACKGROUND & OBJECTIVES: Studies from Western transplant centers have shown the importance of cytomegalovirus (CMV) in infections among immunosuppressed post-transplant patients (both solid and bone marrow transplant recipients). Human herpesvirus-6 (HHV-6) infection is also important. Since such data are lacking from India, we carried out a pilot study to investigate the role of these two viruses in infections among Indian allogeneic bone marrow transplant (BMT) recipients. METHODS: A total of 21 BMT patients who developed acute graft versus host disease (GVHD), two patients who developed chronic GVHD, and eight recipients who did not develop GVHD but had skin rash/elevated liver enzymes, persistent cytopaenia or interstitial pneumonitis with a high clinical suspicion of possible CMV association were studied for markers of CMV and HHV-6 infections. RESULTS: CMV DNAemia was documented in 9 (42.8%) and CMV IgM in 4(19%) of the 21 patients with acute GVHD. HHV-6 DNAemia was not seen in any patient with acute GVHD but 2 (9.5%) had HHV-6 IgM. Of the 2 patients with chronic GVHD, 1 was positive for CMV DNA and IgM, and both were negative for HHV-6 markers. The lower incidence of CMV DNAemia in our recipients may be attributable to the presence of neutralizing antibody (anti gB/AD-1) among the 17 CMV and HHV-6 DNAemia negative recipients, 4(23.5%) had neutralizing antibodies (S/N ratio > or = 5). Of the 13 CMV DNAemia positive recipients, only one (7.7%) was positive for neutralizing antibodies. Among the 5 neutralizing antibody (S/N ratio > or = 5) positive recipients, 4 (80%) were negative for CMV DNAemia. The one nPCR positive was revealed only at high DNA (> 0.1 microgram) input indicating low CMV signal strength. INTERPRETATION & CONCLUSION: The present study shows the use of DNAemia in detecting CMV infections among BMT recipients. All recipients had high avidity CMV IgG (AI > 50%) confirming CMV reactivation or reinfection in these patients. There was evidence from this study suggesting that neutralizing antibodies may play a role in controlling CMV reactivation. We found no significant HHV-6 association with GVHD in Indian allogeneic BMT recipients.

Adolescent↗

PubMed2000

Human herpesvirus 6A DNA Is detected frequently in plasma but rarely in peripheral blood leukocytes of patients after bone marrow transplantation.

A real-time quantitative polymerase chain reaction assay was devised to determine the load of human herpesvirus (HHV)-6A and -6B DNA in paired samples of plasma and peripheral blood leukocytes (PBL) of 25 bone marrow transplant patients. The assay detects HHV-6 DNA variants A and B in a linear range of 10(7)-10(1) genome equivalents per assay. Viral DNA was measured in 336 paired DNA PBL samples and in corresponding plasma samples. HHV-6A and/or -6B DNA was detected in PBL of 23 of 25 patients and in plasma of 24 of 25 patients. HHV-6B was the predominant variant found in PBL and also was detected in the corresponding plasma. Surprisingly, only 1 of 25 patients had detectable HHV-6A DNA in PBL, although 23 of 25 patients were positive for HHV-6A DNA in plasma. HHV-6 DNA load in plasma was significantly higher for HHV-6A than for HHV-6B (P=.0066).

Adolescent↗

PubMed2000

Applicability of an absolute quantitative procedure to monitor intra-individual bcr/abl transcript kinetics in clinical samples from chronic myelogenous leukemia patients.

Chimeric bcr/abl fusion proteins are thought to be the molecular 'pathogen' of chronic myelogenous leukaemia (CML). Expression levels of the respective fusion RNAs reflect disease progression as well as remission upon therapeutic intervention in CML patients. However, there is no quick and reliable method that would allow the quantitative routine monitoring of bcr/abl hybrid transcripts. A fluorescent probe-based PCR assay (TaqMan) has been described to quantitfy the exact amount of target sequences. We have established TaqMan real-time RT-PCRs for M-bcr/abl (b2a2, b2a3, b3a2, b3a3) and m-bcr/abl (e1a2) fusion transcripts as well as for beta-actin. All PCRs quantified as little as 10 copies/100 ng total cDNA. In order to investigate whether this procedure is appropriate for routine diagnostic monitoring, we performed retrospective measurements on 9 documented CML disease courses. Our data show that ongoing or relapsing CML is paralleled by increasing peripheral levels of bcr/abl fusion RNAs. Furthermore, sucessful anti-leukemic treatment is reflected by decreasing absolute bcr/abl transcript numbers. In contrast with conventional bcr/abl PCR techniques we could distinguish single positive values and gradually increasing copy numbers.

Disease Progression↗