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Biomedical subjects

G Ehninger

Publications and source records attributed to G Ehninger.

At least 127 records · Page 7Linked to original sources
PubMed2000

Comparison of spectral karyotyping and conventional cytogenetics in 39 patients with acute myeloid leukemia and myelodysplastic syndrome.

Spectral karyotyping (SKY) was performed in patients with acute myeloid leukemia (AML; n = 25), secondary AML (s-AML; n = 7), myelodysplastic syndrome (MDS; n = 6) and s-MDS (n = 1) to complement conventional cytogenetic investigations. According to the results of conventional cytogenetics the patients were subdivided into three groups: group 1, normal karyotype, n = 19 cases, median age = 64 years; group 2, patients displaying either one or two single aberrations, n = 10 cases, median age = 54 years; group 3, patients with > or =3 independent aberrations, n = 10 cases, median age = 61.5 years. SKY identified no abnormal metaphases in group 1. In one patient of group 2 a hidden translocation t(7;14)(q3?1;q2?2) could be revealed with SKY. Conventional cytogenetics had only shown trisomy 8. A similar t(7;14) was also detected in one patient of group 3. SKY was helpful for the delineation of marker chromosomes and additional material. Furthermore, SKY could distinguish between partial and total monosomies or real existing and apparent deletions. The combination of G-banding, FISH and SKY was found very useful for the precise delineation of the karyotype. As a result of our study we recommend SKY investigation as an important additional tool for accurate chromosome analysis. The detected t(7;14) might represent a novel recurrent translocation in acute myeloid leukemias.

Acute Disease↗
PubMed2000

Diabetes insipidus in a patient with a highly malignant B-cell lymphoma and stomatitis.

A 37-year-old male patient with a diffuse pleomorphic B-cell-lymphoma, which has been diagnosed two month earlier with the primary site at the pterygopalatine fossa on both sides with infiltration of the clivus and cavernous sinus was referred to our hospital for continuation of the third course of CHOP chemotherapy. At admission he reported about a recent history of painful swallowing and intermittent substernal chest pain. Alleviation of the pain on swallowing and the chest pain was apparently only possible by drinking 10 to 15 l of cold coca cola throughout the day and night, a regimen that resulted in polyuria. Physical examination revealed extensive thrush stomatitis and soor esophagitis. Despite successful treatment with fluconazole, polydipsia continued unabated. The classic osmotic test of dehydration and exogenous vasopressin revealed hypothalamic diabetes insipidus (DI). Basal hormones and stimulated endocrine function tests of the adenohypophysis were found to be normal. MRI-scan revealed lymphoma infiltration of the neurohypophysis. After the third course of CHOP chemotherapy the patient surprisingly recovered completely from his excessive thirst. The present report shows that clinical disorders such as thrush stomatitis can mask diabetes insipidus caused by an early relapsing lymphoma.

Adult↗
PubMed2000

Cytokine-driven differentiation of blasts from patients with acute myelogenous and lymphoblastic leukemia into dendritic cells.

We investigated the ability of both acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) blasts to differentiate into dendritic cells (DC) in vitro. Cytokine-supplemented suspension cultures of leukemic blasts in 98 patients with AML and five patients with ALL (normal karyotype, n = 2; BCR/ABL, n = 3) were performed. Mononuclear cells out of peripheral blood or bone marrow containing between 60% and 90% leukemic blasts were cultured for eight days using different growth factor combinations. The highest yield of CD1a(+)/CD14(-) cells could be obtained with stem cell factor, transforming growth factor-beta, tumor necrosis factor-alpha, GM-CSF, and FLT-3-ligand. In the AML samples the median content of CD1a(+)/CD14(-) cells after eight days of culture was 3.5% (r = 0%-82%). In five informed patients CD1a(+)/CD14(-) cells were sorted by fluorescence-activated cell sorting or immunomagnetic separation. Cytogenetic and polymerase chain reaction analyses showed known primary chromosomal aberrations (monosomy 7 and inversion 16) in the sorted fractions, respectively. Dendritic cells (DC) could be generated out of leukemic blasts in 68% of AML patients. Leukemic DC showed no phagocytosis of latex beads, but stimulated allogeneic naive cord blood-derived T cells more efficiently than did uncultured blasts. In ALL patients the median percentage of CD1a(+)/CD14(-) cells was 1.2% (r = 0.7%-3.8%) after culture. The sorted CD1(+)/CD14(-) fractions were BCR/ABL-negative when analyzed with fluorescence in situ hybridization, indicating their nonleukemic origin. Leukemic DC can be generated out of leukemic progenitors in patients with AML. These cells might become relevant for autologous and allogeneic immunotherapy in selected patients. BCR/ABL-positive lymphoblasts could not be transformed into cells with an early dendritic phenotype with the cytokines used in our experiments.

Adolescent↗
PubMed2000

Allogeneic transplantation of G-CSF mobilized peripheral blood stem cells from unrelated donors: a retrospective analysis.

BACKGROUND AND OBJECTIVES: Allogeneic peripheral blood stem cell transplantation (PBSCT) from matched siblings has lead to clinical results comparable to those of standard bone marrow transplantation (BMT). We report the outcome of 79 patients transplanted with PBSC from unrelated donors. DESIGN AND METHODS: In 61 cases PBSC were used for primary transplantation whereas 18 patients were treated for relapse or graft-failure. In 35 patients receiving primary transplants, T-cell depletion (TCD) using CD34 positive selection of PBSC with or without additional T-cell depletion had been performed to reduce the risk of graft-versus-host-disease (GvHD). RESULTS: The rate of primary graft-failure was higher (20%) in the TCD group than in that receiving unmanipulated grafts (UM) (5%, p=0.007). Patients with standard risk (n=34) receiving first transplants had a significantly better overall (60.4% vs. 24%, p=0.02) and disease-free survival (57.2% vs. 22.3%, p=0.006) compared to a high risk group of patients (n=21). There were no differences in the speed of neutrophil and platelet engraftment between TCD and UM transplants. As expected, the cumulative risk for acute GvHD grade II.-IV was significantly higher in the patients who had received UM grafts (71.8% vs. 38.1%, p=0.005). Although a trend towards a better survival rate was observed after TCD transplantation (52.2%) compared to the UM group (38.1%), this difference was not statistically significant. The probability of relapse was significantly higher in patients after UM transplants (38.8% vs. 8. 4%). This apparent paradox is explained by the higher number of high-risk patients in this group (p=0.03). Multivariable analysis of disease-free survival revealed risk category (p=0.02) and use of ATG (p=0.03) to be of significant impact. All patients (n=6) with non-malignant diseases are alive with full donor chimerism. INTERPRETATION AND CONCLUSIONS: These data show that PBSC from unrelated donors can be transplanted either unmanipulated or CD34 selected. Prospective studies comparing BMT with PBSCT from unrelated donors are needed in defined disease categories.

Adolescent↗
PubMed2000

Clinical phase I dose escalation and pharmacokinetic study of high-dose chemotherapy with treosulfan and autologous peripheral blood stem cell transplantation in patients with advanced malignancies.

A Phase I dose escalation and pharmacokinetic study of the alkylating cytotoxic agent treosulfan was conducted to evaluate the maximum tolerated dose and the dose-limiting toxicities in patients with advanced malignancies rescued by autologous peripheral blood stem cell transplantation. Twenty-two patients (15 ovarian and 7 other carcinomas/lymphomas) with a median age of 48 years were treated with 28 high-dose courses. Treosulfan was infused over 2 h at escalating doses from 20 to 56 g/m2, and pharmacokinetic parameters were analyzed. At 56 g/m2, three of six patients experienced dose-limiting toxicities: diarrhea grade III/IV in three patients; mucositis/stomatitis grade III in one patient; toxic epidermal necrolysis in one patient; and grade III acidosis in one patient. Other low-grade side effects, including erythema, pain, fatigue, and nausea/vomiting, were recorded. Two patients died within 4 weeks after treatment because of rapid tumor progression and fungal infection, respectively. Plasma half-life, distribution volume, and renal elimination of treosulfan were independent of dose, whereas the increase in area under the curve was linear up to 56 g/m2 treosulfan. The maximum tolerated dose of high-dose treosulfan is 47 g/m2. A split-dose or continuous infusion regimen is recommended for future high-dose trials. In consideration of antineoplastic activity and limited organ toxicity, inclusion of high-dose treosulfan in combination protocols with autologous peripheral blood stem cell transplantation seems worthwhile.

Adult↗
PubMed2000

Approaches to managing volunteer marrow donor registry HLA data. Algorithms for directing donor center-initiated HLA-DR typing of selected donors.

The German bone marrow donor center (DKMS) hasrecruited over 732 500 donors during the first 9 years of its existence. Initially, donors were typed for HLA-A and B, and DR typing was only done on request for a patient-initiated search. In 1994, a project was started which led to the donor center-initiated DR typing (DCI-DRT) of >35,000 donors. These donors were selected by donor-specific criteria (age, sex, height and weight) and according to HLA-A and B phenotypes. The latter was done to avoid unnecessary DR typing of the most common A, B phenotypes With a follow up of >6 years, this strategy has led to a number of confirmatory typings (CT) (n=4588) and stem cell harvests (n=568), which is at least comparable to those ensuing after patient-initiated HLA-DR typing (126 000 DR typings, 8,213 CTs, 888 resulting in stem-cell donation). DCI-DRT seems to be a cost-effective strategy which may help to reduce search times and improve search outcome, and improve the overall efficiency of donor center operations

Adolescent↗
PubMed1999

Interferon-alpha before allogeneic bone marrow transplantation in chronic myelogenous leukemia does not affect outcome adversely, provided it is discontinued at least 90 days before the procedure.

The influence of interferon-alpha (IFN) pretreatment on the outcome after allogeneic bone marrow transplantation (BMT) in chronic myelogenous leukemia (CML) is controversial. One goal of the German randomized CML Studies I and II, which compare IFN +/- chemotherapy versus chemotherapy alone, was the analysis of whether treatment with IFN as compared to chemotherapy had an influence on the outcome after BMT. One hundred ninety-seven (23%) of 856 Ph/bcr-abl-positive CML patients were transplanted. One hundred fifty-two patients transplanted in first chronic phase were analyzed: 86 had received IFN, 46 hydroxyurea, and 20 busulfan. Forty-eight patients (32%) had received transplants from unrelated donors. Median observation time after BMT was 4.7 (0.7 to 13.5) years. IFN and chemotherapy cohorts were compared with regard to transplantation risks, duration of treatments, interval from discontinuation of pretransplant treatment to BMT, conditioning therapy, graft-versus-host disease prophylaxis and risk profiles at diagnosis and transplantation, and IFN cohorts also with regard to performance and resistance to IFN. Outcome of patients receiving related or unrelated transplants pretreated with IFN, hydroxyurea, or busulfan was not significantly different. Five-year survival after transplantation was 58% for all patients (57% for IFN, 60% for hydroxyurea and busulfan patients). The outcome within the IFN group was not different by duration of prior IFN therapy more or less than 5 months, 1 year, or 2 years. In contrast, a different impact was observed in IFN-pretreated patients depending on the time of discontinuation of IFN before transplantation. Five-year survival was 46% for the 50 patients who received IFN within the last 90 days before BMT and 71% for the 36 patients who did not (P =.0057). Total IFN dosage had no impact on survival after BMT. We conclude that outcome after BMT is not compromised by pretreatment with IFN if it is discontinued at least 3 months before transplantation. Clear candidates for early transplantation should not be pretreated with IFN.

Adolescent↗
PubMed1999

Stable engraftment after megadose blood stem cell transplantation across the HLA barrier: the case for natural killer cells as graft-facilitating cells.

BACKGROUND: The case of a patient with chronic myelogenous leukemia who underwent transplantation with highly purified CD34+ peripheral blood stem cells from his two-antigen-mismatched mother is reported. No graft-versus-host disease has been observed so far and stable engraftment has been documented until day 100. METHODS: Weekly analysis of chimerism in different cellular subsets was performed using a quantitative polymerase chain reaction assay for nine short tandem repeat markers in leukocytes sorted by fluorescence-activated cell sorting. RESULTS: No donor CD4+ or CD8+ T cells have been detected up to 3 months after transplantation, whereas a rapid increase of donor CD56+ natural killer (NK) cells was observed in parallel with circulating donor CD34+ progenitors and myeloid cells. CONCLUSIONS: Because the graft contained virtually no T and NK cells, we believe the rapid in vivo generation of NK cells supported stable engraftment across the HLA barrier. The differentiation of CD34+ progenitors into NK cells might be a distinct feature of megadose stem cell transplants.

Adult↗
PubMed1999

Peripheral blood stem cell transplantation from unrelated donors: a comparison with marrow transplantation.

Peripheral blood stem cell (PBSC) transplants from HLA-A, -B, and -DR compatible unrelated donors (n = 45) were compared with bone marrow (BM; BM group, n = 45). Eighteen patients received CD34-selected PBSC (CD34 group). The PBSCs contained more mononuclear cells, CD34(+), CD3(+), and CD56(+) cells compared with marrow (P <.001). Engraftment was achieved in all 45 patients in the BM group, in 43 of 45 (95%) in the PBSC group, and in 14 of 18 (78%) in the CD34 group (P <.01). In multivariate analysis, a short time to absolute neutrophil count (ANC) equal to 0.5 x 10(9)/L was associated with the PBSC/CD34 groups (P <.001) and granulocyte colony-stimulating factor (G-CSF) treatment (P =.017). A short time to platelets equal to 50 x 10(9)/L was associated with PBSC (P =. 003) and no methotrexate (P =.015). Grades II-IV acute graft-versus-host disease (GVHD) was 20% in the BM controls, 30% in the PBSC group, and 18% in the CD34 group (not significant [NS]). The probability of chronic GVHD was 85% in the BM group, 59% in the PBSC group, and 0% in the CD34 group (P <.01). One-year transplant-related mortality was 21% and 27% and survival was 53% and 54% in the BM and PBSC groups, respectively (NS). The 2-year relapse-free survival was 41% and 46% in the two groups, respectively.

Adult↗
PubMed1999

Mycophenolate mofetil and cyclosporine as graft-versus-host disease prophylaxis after allogeneic blood stem cell transplantation.

BACKGROUND: Mycophenolate mofetil (MMF) is an inhibitor of purine nucleotide de novo synthesis leading to impaired proliferation of activated lymphocytes. Studies in animals show a synergistic effect of MMF and cyclosporine (CsA) in preventing acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation. We performed a pilot study evaluating the feasibility of the combined application of MMF and CsA as GVHD prophylaxis after allogeneic blood stem cell transplantation. Toxicity and the bioavailability of MMF in this setting were investigated. METHODS: Fourteen patients who had received grafts from HLA-compatible siblings received 2 g of oral MMF from day 1 to 14 combined with intravenous CsA at 4 mg/kg starting at day-1. Plasma levels of mycophenolic acid (MPA) and its glucoronide were measured by high-performance liquid chromatography. Fifteen patients treated with a combination of CsA and methotrexate at the same institution were referred to as the control group. RESULTS: Trilineage engraftment was achieved in all study and control patients. Acute GVHD > or = grade II was observed in 46.5% and 60% of the study and control patients, respectively. No major differences in the rate of acute toxicities were detectable. The mean trough blood level of MPA in 10 patients was 0.28 microg/ml, and 5.7 microg/ml for MPA glucoronide. Reduced peak levels of MPA indicate a reduced absorption rate of MMF in the early posttransplant phase. CONCLUSIONS: The combined administration of MMF and CsA was shown to be feasible in patients after allogeneic blood stem cell transplantation. Because of the decreased bioavailability of MMF, dose-finding studies for an intravenous formulation are warranted.

Adult↗
PubMed1999

Defining optimum conditions for the ex vivo expansion of human umbilical cord blood cells. Influences of progenitor enrichment, interference with feeder layers, early-acting cytokines and agitation of culture vessels.

Ex vivo expansion of human umbilical cord blood cells (HUCBC) is explored by several investigators to enhance the repopulating potential of HUCBC. We performed experiments using either Ficoll-separated or CD34+-selected HUCBC from the same donation in serum-free medium. CD34-purified HUCBC were cultured on either human umbilical vein endothelial cells (HUVEC) or irradiated bone marrow-derived stroma cells (BMSC) with addition of different cytokines. In addition, we tested the expansion of HUCBC in culture vessels with continuous rotation. CD34 enrichment led to a significant increase in the expansion factor of CD34+ cells compared with unmanipulated HUCBC. BMSC were more efficient in amplifying early progenitors than HUVEC. Optimum results were reached by a combination of SCF, FLT-3L at 300 ng/ml and IL-3 at 50 ng/ml. No significant improvement in the expansion of CD34+/38- primitive progenitors could be obtained with other combinations. Addition of megakaryocyte-derived growth and development factor to each growth factor cocktail improved the expansion results. Continuous rotation of culture vessels did not ameliorate the expansion rate of the analyzed subsets. Culture conditions separating stroma and HUCBC by a semipermeable membrane improved the expansion factors of CD34+, CD34+/38-, and CD34+/41+ cells and CFU-GM compared with contact cultures. These data might be useful when designing culture systems for clinical scale ex vivo expansion of HUCBC.

Antigens, CD34↗
PubMed1999

Relations between IL-3-induced proliferation and in vitro cytokine secretion of bone marrow cells from AML patients.

The influence of IL-3 on the bone marrow cells of 53 patients with acute myeloid leukaemia (AML) was investigated after 72 h suspension in cultures by analysing the proliferation of blasts and the secretion of cytokines. The titres of IL-1beta IL-6, TNF-alpha and IL-3 were measured in the supernatants of these cultures with ELISA tests. Comparing the percentage of cells in S-phases of control cultures and cultures with IL-3, the leukaemias were divided into two growth pattern groups: IL-3-insensitive (n=19) and IL-3-sensitive (n=34) leukaemias. The IL-3-insensitive AML cells show a greater ability for autonomous growth, first by the increase of S-phase in the control culture compared with the S-phase in vivo (P=0.0486) and second, by the higher constitutive secretion (control culture) of IL-1beta P =0.0004), IL-6 ( P =0.0395) and TNF-alpha P=0.0005). The IL-3-induced secondary cytokine secretion is also different in the two growth pattern groups. Whereas in the IL-3-insensitive AML cells a moderate increase of IL-1beta (1.48-fold increase) was present, in the IL-3-sensitive AML cells a 4.72-fold increase of IL-1beta 2.71-fold increase of IL-6 and 11.81-fold increase of the TNF-alpha titre could be detected. Overall, the data show an inverse correlation between the ability of AML cells to respond to IL-3 with increase of an S-phase and the constitutive secretion of IL-1beta, II-6 and TNF-alpha. A further effect of IL-3 is the induction of secondary cytokine secretion in the bone marrow of IL-3-sensitive growing AML cells.

Acute Disease↗
PubMed1999

Drug resistance testing of acute myeloid leukemia in adults using the MTT assay.

OBJECTIVE: We want to evaluate the MTT in vitro assay for newly diagnosed AML in adults, in particular its prognostic significance. METHODS: MTT tests were performed according to Pieters et al., Blood 76: 2327, 1990. Up to 18 cytostatic drugs were tested in a wide range of concentrations over 4 days and compared with controls. If necessary, blasts were enriched > 80% by negative selection with dynabeads (Kaspers et al., Br. J. Cancer 70: 1047, 1994). Percent S-phase was measured at begin of assay and after 4 days. RESULTS: Technical success rate was 80-85% and the assay took about one day of work. IC50 values as a measure for drug resistance were highly reproducible with an interassay CV (range) of 28% (13-47) between days. Median cell viability of controls after 4 days was 80% (44-97);% S-phase at begin of assay was 3% (0.1-15) and after 4 days 9% (1-39). Leukemic blasts from 57 adult AML patients were prospectively tested in vitro at diagnosis. Large interindividual differences in drug resistance were observed (over 1000 fold on average). There was a trend for greater IC50 with higher cytogenetic risk and nonresponders to induction. Other clinical prognostic factors such as patient age, initial WBC, FAB subtype, prior MDS and % S-phase did not show a relationship with the in vitro data. There was a high correlation between the topoisomerase II related drugs regarding in vitro resistance. CONCLUSION: In vitro sensitivity tests like the MTT assay may provide a valuable tool for prediction of individual therapy outcome in combination with cytogenetics. However, longer follow-up is required.

Adolescent↗
PubMed1999

A new PCR MIMIC strategy to quantify low mdr1 mRNA levels in drug resistant cell lines and AML blast samples.

Determination of the MDR-phenotype in patients suffering from AML is an important hallmark of treatment outcome but is often complicated by technical problems in P-gp assessment. A PCR-MIMIC strategy was employed to construct PCR-fragments for a competitive and quantitative mdr1 reverse transcription-PCR-assay. Using K562 cells, which had been selected for drug resistance to the epipodophyllotoxin VP16, a stepwise increase of mdr1 levels depending on the concentration of VP16 was shown with the MIMIC technique. Comparison of mdr1 levels in drug selected K562 cells with the corresponding levels for P-gp and functional data indicated a mRNA threshold that has to be exceeded for the full expression of the MDR-phenotype. Subsequently mdr1 levels of 34 samples of de novo acute myeloid leukemia were determined with the PCR-MIMIC strategy. Ten patient samples could be identified with elevated mdr1 levels which were substantially lower than the levels observed in the MDR-cell line K 562 0.7 microM VP16. Outcome analysis revealed that eight of the ten patients had an unfavourable prognosis and did not achieve CR after induction chemotherapy. Coexpression of mdr1 and CD 34 was not associated with CR in all examined cases. Moreover all these patients had unfavourable cytogenetic aberrations. These data indicate a sensitive technique with applicability in patient material.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Myeloablation by intravenous busulfan and hematopoietic reconstitution with autologous marrow in a canine model.

We have previously described pharmacokinetic studies with a dimethylsulfoxide-based intravenous busulfan preparation in a canine model and in preliminary clinical trials. Using the same intravenous busulfan preparation, we carried out a dose escalation study to determine a marrow-ablative dose and to test the ability of autologous marrow to reconstitute hematopoiesis in dogs so treated. Busulfan was given intravenously at doses of 3.75 to 40 mg/kg. Marrow ablation was achieved at 20 mg/kg given either as a single dose or in four daily increments of 5 mg/kg each. There was a relative sparing of lymphocytes. A busulfan dose of 40 mg/kg resulted in severe central nervous system toxicity. Otherwise, nonhematopoietic toxicity was minimal and restricted to mild hepatic abnormalities. Four dogs were given busulfan at 20 mg/kg followed 30 hours later by infusion of autologous marrow, and all showed prompt and complete hematopoietic reconstitution. The area under the curve (AUC) determined by busulfan concentration in plasma over time was dose dependent, ranging from 12 to 100 microg x h/mL for busulfan doses of 3.75-20 mg/kg. There was a suggestion that the plasma half-life increased at the highest busulfan doses used. Intravenous administration of busulfan circumvented differences in bioavailability; nevertheless, considerable variations in the pharmacokinetic parameters were observed between individual animals. Thus, intravenous busulfan can be given safely and is effective in ablating hematopoiesis. However, factors other than absorption influence the AUC, and individualization of dosing may be required even with intravenous administration of the drug.

Animals↗
PubMed1999

Flow cytometric DNA quantification in immunophenotyped cells as a sensitive method for determination of aneuploid multiple myeloma cells in peripheral blood stem cell harvests and bone marrow after therapy.

The simultaneous measurement of DNA content and myeloma-related antigens (B-B4 or CD38) by flow cytometry is proposed as a method for the detection of aneuploid plasma cells in peripheral blood stem cell (PBSC) harvests and in bone marrow after therapy. In 30 patients with initially detected aneuploid myeloma cells we evaluated the bone marrow after therapy and in eight of these patients 23 PBSC harvests were analyzed. In 13 of 23 PBSC harvests aneuploid myeloma cells were detectable (range: 0.02-0.63%). In the bone marrow of the 30 patients aneuploid plasma cells were detectable in all samples after chemotherapy (range: 0.12-35.70%) and after autologous PBSC transplantation in two of three patients (0.21% and 0.03%). Furthermore the relationship between diploid and aneuploid plasma cells can be evaluated. In the PBSC harvests the percentage of aneuploid plasma cells is significantly lower than that of diploid plasma cells (P=0.006). In contrast, in bone marrow the aneuploid plasma cells are predominant in most patients even after therapy (24 of 30 patients; P=0.0055). In the case of initially detected aneuploid myeloma cells, a contamination with malignant cells can be estimated with a simple flow cytometric method in PBSC harvests and in bone marrow after therapy.

Aneuploidy↗