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Biomedical subjects

G Ehninger

Publications and source records attributed to G Ehninger.

At least 145 records · Page 8Linked to original sources
PubMed1999

Rapid quantification of mixed chimerism using multiplex amplification of short tandem repeat markers and fluorescence detection.

Monitoring the engraftment of donor cells after allogeneic blood stem cell transplantation (BSCT) may be important for the early diagnosis of graft failure or relapse of disease. Several techniques have been reported for this purpose. PCR-based assays analyzing polymorphic short tandem repeat (STR) markers are attractive because they are sensitive and can be performed rapidly. The intent of the present study was to test a novel approach for the quantification of mixed chimerism using a commercial multiplex STR assay with fluorescence-based detection for forensic purposes. The feasibility of this assay and the accuracy of quantitative results was tested using serial cell mixtures of unrelated individuals. Sample preparation was optimized to obtain information from minute amounts of starting material, eg from patients with aplasia or from sorted cell populations. Using the STR-PCR, discrimination between donor and recipient was possible in all patients analyzed (n = 25). Cell dilution experiments showed a linear correlation between the cell numbers added and the proportions found, with the limit of detection for a minor cell population being 5%. Comparison of values obtained with standard FISH analysis in patients transplanted from sex-mismatched donors showed an excellent correlation with the STR-PCR results. Taken together, this procedure allows the rapid, versatile and accurate quantification of mixed chimerism, even with minuscule numbers of cells.

Amelogenin↗
PubMed1999

Detection of cytogenetic aberrations both in CD90 (Thy-1)-positive and (Thy-1)-negative stem cell (CD34) subfractions of patients with acute and chronic myeloid leukemias.

Acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) are thought to arise from malignant hematopoietic progenitor cells representing early and undifferentiated stem cell clones. In CML there is evidence for a progenitor cell subset free of leukemic clones, depending on the course of the disease. Additionally, it has been suggested that in AML, the early stem cell compartment (CD34+/90+) does not harbor the malignant clone. We analyzed white blood cells from leukemia patients for the presence of aberrant cells in stem cell subfractions. Sixteen patients with CML, six patients with AML, two patients with acute lymphatic leukemia (ALL) and one with chronic myelomonocytic leukemia (CMMOL), all with known cytogenetic abnormalities, were evaluated according to their CD90 (Thy-1)-positive or -negative phenotype. Subsets were sorted on to slides and further characterized by FISH and/or standard cytogenetic testing. The bcr-abl translocation or gross chromosomal abnormalities could be detected in equally high amounts of 92.2% and 89.2% in both stem cell subsets. We conclude, that in progressed AML and CML cells characterized by specific genetic aberrations implicated in the malignant state can be found in the CD34+/CD90+ and CD90- population, thus making CD90 an inappropriate marker to distinguish benign from malignant cells in these leukemias.

Acute Disease↗
PubMed1999

Experiences of the Dresdner Cord Blood Bank, supported by the Deutsche Knochenmarkspenderdatei.

Allogeneic bone marrow and peripheral blood stem cell transplantation is the treatment of choice for some malignant hematologic diseases, marrow failure syndromes, and severe congenital immunodeficiency states. Since Gluckman et al reported in 1988 the first successful human leukocyte antigen (HLA)-matched sibling umbilical cord blood stem cell transplantation, it has been known that cord blood is a valuable source of hematopoietic stem cells. The Cord Blood Bank at the University Hospital of Dresden was founded in 1997 and started collecting, processing, and cryoconserving umbilical cord blood in August 1997. The cord blood bank is supported by the largest German donor registry: Deutsche Knochenmarkspenderdatei (DKMS) in Tubingen, Germany. With the informed consent of the mothers, the collection is performed in collaboration with six hospitals in Dresden, Berlin, and Bautzen. We routinely perform a volume reduction by centrifuging the blood bag and expressing the leukocyte-rich supernatant. Routinely, sterility, total nucleated cells (TNC), CD34+ cell count, HLA class I and II, ABO/Rh blood group, and colony-forming units are evaluated. The maternal blood is screened for anti-immunodeficiency virus (anti-HIV), anti-hepatitis C virus (anti-HCV), anti-hepatitis B surface antigen (HBsAg), anti-hepatitis B surface (anti-HBs), anti-hepatitis B core (anti-HBc), anticytomegalovirus (anti-CMV), and toxoplasmosis and with Treponema pallidum hemagglutination assay (TPHA). More than 1,000 cord blood units could be collected. Because of the required volume and cell count and because of sterility, 50% of the collected units had to be discharged. Our results are comparable with data of other cord blood banks: mean volume 79 mL; cell count after volume reduction-TNC, 7.16 x 10(8); mononucleated cells (MNC), 3.75 x 10(8); CD34+ cells, 1.95 x 10(6); colony-forming units (CFU), 67.1 x 10(4). To increase the pool of potential umbilical cord blood units and in order to evaluate the possibility for unrelated transplants, cryopreservation and banking of large numbers of cord bloods are necessary.

Animals↗
PubMed1999

Leptin and its receptor in normal human gastric mucosa and in Helicobacter pylori-associated gastritis.

BACKGROUND: Leptin, a newly discovered weight-reducing hormone, is mainly produced in fat cells. Recently, this hormone has been reported to be produced in rat gastric mucosa cells. In the present study we analyzed the localization and expression of leptin and its receptors in normal human gastric mucosa and in patients with Helicobacter pylori-associated gastritis. METHODS: Plasma leptin levels and gastric mucosa leptin content were determined in 39 patients with dyspepsia. Cellular localization of leptin and of the signaling receptor (Ob-RL) were assessed by immunohistochemistry. Reverse transcriptase polymerase chain reaction (RT-PCR) for leptin receptor isoforms was performed on gastric epithelial cells isolated by laser-capture-microdissection. RESULTS: Leptin content of the corpus gastric mucosa in H. pylori-positive patients was significantly increased (4.6+/-1.2. n = 15) as compared with the H. pylori-negative group (27.5+/-0.5 pg/mg, n = 24, P = 0.006). The presence of leptin immunoreactivity was shown in the lower half of corpus epithelial glands. By RT-PCR no leptin mRNA was detectable in human gastric tissue. In contrast, expression of both Ob-R(L) and the leptin receptor isoforms could be detected in gastric epithelial cells. Leptin receptor protein was detected throughout the mucosa. CONCLUSIONS: Leptin itself is stored and secreted but not produced in human gastric mucosa. The functional receptor and all isoforms are present in human gastric mucosa. H. pylori-associated gastritis leads to significant increases in local leptin concentration in the gastric corpus.

Analysis of Variance↗
PubMed1999

[Candidiasis in cancer patients: Epidemiology, diagnosis, prophylaxis and therapy].

New approaches in successful treatment of cancer patients are impaired by increasing incidence of fungal infections with high mortality. Relevant prognostic factors could be identified by numerous trials, such as age, kind and status of disease, intensity of previous chemotherapy, bone marrow transplantation, advanced fungal colonization of gastrointestinal tract. In clinical practice options for prompt and sensitive diagnostics are limited despite of new PCR-techniques. Prophylactic efficiency of polyenes or azoles is proven in high risk patients. Amphotericin B is established for treatment in case of documented or assumed invasive fungal infection. Liposomal preparations are less toxic and at least as effective as conventional amphotericin B in randomized trials.

Amphotericin B↗
PubMed1998

Safety and cost effectiveness of a 10 x 10(9)/L trigger for prophylactic platelet transfusions compared with the traditional 20 x 10(9)/L trigger: a prospective comparative trial in 105 patients with acute myeloid leukemia.

In 105 consecutive patients with de novo acute myeloid leukemia (French-American-British M3 excluded), we compared prospectively the risk of bleeding complications, the number of platelet and red blood cell transfusions administered, and the costs of transfusions using two different prophylactic platelet transfusion protocols. Two hundred sixteen cycles of induction or consolidation chemotherapy and 3,843 days of thrombocytopenia less than 25 x 10(9)/L were evaluated. At the start of the study, each of the 17 participating centers decided whether they would use a 10 x 10(9)/L prophylactic platelet transfusion trigger (group A/8 centers) or a 20 x 10(9)/L trigger (group B/9 centers). Bleeding complications (World Health Organization grade 2-4) during treatment cycles were comparable in the two groups: 20 of 110 (18%) in group A and 18 of 106 (17%) in group B (P = .8). Serious bleeding events (grade 3-4) were generally not related to the patient's platelet count but were the consequence of local lesions and plasma coagulation factor deficiencies due to sepsis. Eighty-six percent of the serious bleeding episodes occurred during induction chemotherapy. No patient died of a bleeding complication. There were no significant differences in the number of red blood cell transfusions administered between the two groups, but there were significant differences in the number of platelet transfusions administered per treatment cycle: pooled random donor platelet concentrates averaged 15.4 versus 25.4 (P < .01) and apheresis platelets averaged 3.0 versus 4.8 (P < .05) for group A versus group B, respectively. This resulted in the cost of platelet therapy being one third lower in group A compared with group B without any associated increase in bleeding risk.

Acute Disease↗
PubMed1998

Computer-based quality control in high-dose chemotherapy and bone marrow transplantation.

High-dose chemotherapy with autologous and allogeneic blood stem cell transplantation has become a standard therapy for hematological malignancies and solid tumors. To ensure quality of treatment and adherence to internationally approved protocols, the use of computer systems has been introduced in some oncology centers. Most software packages cannot be used automatically by other institutions because of different treatment strategies and medications. To overcome this problem, we designed a software system based on an Oracle database, which allows the user to develop his own therapy blocks and assemble them to generate specific therapy plans. The system supports the daily work of the physicians by suggesting medications based on changes in the vital parameters or the clinical chemistry. Parameters can be given upper and lower limits whose surpassing leads to treatment suggestions by the system. All quantitative variables may be depicted in a graphical way. The system is connected to external laboratory devices. Export of data to international registries is possible. Until now, 43 patients have been transplanted with the help of this system. There is a high degree of acceptance among the nursing staff and the physicians. The system can be transferred to other centers, if the local hardware and network capacities meet the minimal requirements.

Adult↗
PubMed1998

Pharmacokinetics of intravenous busulfan and evaluation of the bioavailability of the oral formulation in conditioning for haematopoietic stem cell transplantation.

Busulfan (BU) is included in many conditioning protocols for haematopoietic stem cell transplantation (HSCT). Pharmacokinetic parameters in individual patients have been related to short-term toxicity and risk of relapse after HSCT. In a series of 11 patients receiving the usual 16 x 1 mg/kg schedule over 4 days, we investigated the pharmacokinetics of replacing one dose with an intravenous formulation (BU in DMSO) which we had previously investigated in dogs. A dose of 0.5-0.6 mg/kg was used. No acute side-effects of BU/DMSO infusions administered over 1 h were observed. Bioavailability of BU powder capsules was on average 70% (range, 44-94%). Interindividual variability of the resulting AUC after intravenous doses was still substantial. Further studies are under way to define the possible role of BU/DMSO infusions in conditioning before HSCT.

Administration, Oral↗
PubMed1998

Fluorescence in situ hybridization for the BCR/ABL rearrangement is dependent on the percentage of nonlymphocytic cells in peripheral blood stem cell harvests.

Interphase fluorescence in situ hybridization (FISH) for the translocation t(9;22) is widely used for quantifying minimal residual disease (MRD) in PBSC harvests from CML patients. We investigated the influence of cell composition on the percentage of positive FISH signals in 17 BCR/ABL-positive leukapheresis products from 12 CML patients. In these PBSC harvests, a significant correlation between the percentage of nonlymphocytic nucleated cells and BCR/ABL positivity was measured (k=0.81). This correlation was not seen in patients who became BCR/ABL negative after mini-ICE chemotherapy. CD34 enrichment was performed by immunomagnetic separation in 7 patients. There was a statistically significant increase in BCR/ABL positivity after CD34+ selection (p=0.018). This may have been caused by passive depletion of BCR/ABL-negative lymphocytes. Our findings suggest that quantitative results of t(9;22) FISH have to be corrected for cell composition when comparing different stem cell products. CD34+ selection before FISH analysis may be one way to enrich for nonlymphocytic cells and to concentrate on the progenitor compartment.

Adult↗
PubMed1998

The incidence of DNA aneuploidy in multiple myeloma does not correlate with stage of disease.

The bone marrow of 47 patients with multiple myeloma (MM), 2 patients with plasma cell leukemia, and 11 patients with monoclonal gammopathy of undetermined significance (MGUS) was analyzed by flow cytometry for the detection of DNA aneuploidy. The question to be addressed was whether a correlation exists between the incidence of DNA aneuploidy and the stage of disease. With one-parameter analysis of DNA staining, a DNA aneuploidy was detectable in 17 of 60 patients. The detection rate for DNA aneuploidies could be increased to 37 of 60 patients with the second method, the simultaneous measurement of DNA content in additional immunophenotyped cells (CD38 or B-B4). In MGUS and the early stages of MM, the discrepancy between both methods was higher than in stage III MM. There were no statistical differences in the incidence of DNA aneuploidy between MGUS or the early stages of MM and stage III MM (21/32 patients vs 16/26 patients). The CD56 expression in plasma cells was significantly higher in cases of DNA aneuploidy (mean +/- SD, 64.7% +/- 33.65% vs 39.3% +/- 36.69%; P = .028). Comparing the ratio of diploid to DNA aneuploid with that of CD56+ to CD56- plasma cells, a correlation was found in MGUS (r = 0.7320) in the early stages of MM, I and II (r = 0.8023), but not in stage III MM. Based on these data, the dual-staining method for DNA content in immunophenotyped cells is preferred for the detection of DNA aneuploidy, especially in the early stages of MM and in MGUS. The clinical importance of a classification of DNA aneuploidy and CD56 antigen expression together is proposed for testing.

ADP-ribosyl Cyclase↗
PubMed1998

Ongoing somatic mutations and clonal expansions after cure of Helicobacter pylori infection in gastric mucosa-associated lymphoid tissue B-cell lymphoma.

PURPOSE: Although most patients with primary gastric low-grade mucosa-associated lymphoid tissue (MALT) B-cell lymphoma experience complete endoscopic and histologic remission after the cure of Helicobacter pylori infection, in many patients, the polymerase chain reaction (PCR) still detects monoclonal B cells in the gastric mucosa. The present study asked whether the lymphoma immunoglobulin VH (IgVH) sequences remained stable in patients with gastric MALT lymphoma after H pylori eradication. PATIENTS AND METHODS: Eight patients with stage EI disease treated with H pylori eradication were analyzed before and at different time points after the cure of the infection. After the amplification of IgVH genes from DNA extracted from gastric biopsy specimens, monoclonal PCR products were cloned and multiple clones (43 to 105) were sequenced per patient. RESULTS: Mutations were detected in all lymphoma VH sequences, which suggested germinal center or postgerminal center origin of the lymphoma B cells. In five of the eight patients, clonal heterogeneity was observed at diagnosis or during follow-up. Genealogical analysis of shared and unshared mutations showed that the process of somatic mutations was ongoing after H pylori eradication in four of the five patients who showed clonal instability. Ongoing mutations were observed in three of the four patients who completely responded to H pylori eradication, but in only one of the four patients who did not respond or who partially responded. CONCLUSION: In low-grade gastric MALT lymphomas, an ongoing process of somatic hypermutation and antigen selection can be detected after the therapeutic removal of the underlying stimulus H pylori. These data point to the relevance of yet unknown antigens that drive this disease. In addition, they challenge the view that these lymphomas may be cured solely by the eradication of H pylori.

Adult↗
PubMed1998

Acceptance and feasibility of peripheral stem cell mobilisation compared to bone marrow collection from healthy unrelated donors.

Allogeneic peripheral blood stem cell transplantation leads to an earlier engraftment compared to BMT. The feasibility, acceptance and long-term side-effects of G-CSF mobilisation of PBSC in unrelated healthy donors needs to be evaluated. Forty unrelated healthy donors received G-CSF in a dose of 10 microg/kg bodyweight for 5 days and two aphereses were performed. The donors were monitored prospectively. The data were compared to bone marrow harvests from unrelated donors. Almost all stem cell donors reported some side-effects due to Filgrastim application. Bone pain (32), headache (20), chest pain (two) and night sweats (one) were complained of. By taking analgesics, the pain was relieved in most cases. No donor discontinued the filgrastim application. Bone pain and headache resolved within 2-4 days after termination of Filgrastim application. There was, as expected, a seven-fold increase in the number of total WBCs. There were no significant changes of platelet counts during G-CSF application. After 4 weeks haemoglobin concentration and platelet counts showed no significant differences compared to baseline values. The aphereses were mostly tolerated very well. Eighteen donors reported paraesthesia, one donor developed dizziness, two complained of nausea and vomiting. There was a significant decrease in platelet count (242 before, 98 x 10(9)/l after aphereses). Autologous platelets were transfused after the second aphereses in four donors. These data were compared to data from 245 unrelated bone marrow donors, who had on average, 14 days bone pain and tiredness after donation. The G-CSF mobilisation and apheresis of peripheral blood stem cells is an alternative to traditional bone marrow harvesting in unrelated healthy donors. It is well tolerated and the duration of side-effects on average is shorter than after the surgical procedure. So far no long-term effects have been observed in the follow-up.

Adult↗
PubMed1998

Abdominal lymphomas, convulsive seizure and coma: a case of successfully treated, advanced Whipple's disease with cerebral involvement.

Whipple's disease is a rare, generalized inflammatory disorder due to the recently described bacterium Tropheryma whippelii. We report an unusual, successfully treated case of a 32-year-old woman, who presented with a 25 month history of large abdominal lymphomas, polyserositis and cachexia. The diagnosis of Whipple's disease was confirmed by duodenoscopy, lymph node and duodenal histology and polymerase chain reaction analysis of biopsy material and cerebrospinal fluid. A prolonged convulsive seizure with a subsequent 5 day period of coma were interpreted as signs of cerebral involvement. Under antibiotic treatment with trimethoprim-sulfamethoxazole (co-trimoxazole) the patient recovered completely, CT scans showed a complete regression of abdominal lymphomas. The therapy was continued over 18 months without the occurrence of a relapse.

Abdominal Neoplasms↗
PubMed1997

Supplementation with antioxidants prior to bone marrow transplantation.

Conditioning therapy preceding bone marrow transplantation (BMT) usually consists of high-dose chemotherapy and total body irradiation (TBI). It has acute and delayed toxic effects on several tissues, possibly related to peroxidation processes and exhaustion of antioxidants. Early studies indicated an increase of peroxide processes and a decrease of antioxidants during conditioning therapy. Hence, we investigated the effect of antioxidant supplementation on peroxidation processes and antioxidant status. We supplemented a patient group (N = 16) [BMT (+)], with oral 45 mg beta-carotene, 825 mg alpha-tocopherol and 450 mg ascorbic acid daily for three weeks before conditioning therapy. Another patient group (N = 10), BMT(-), was not supplemented with antioxidants before conditioning therapy. In order to investigate the physiologic effect of supplement antioxidants a healthy control group (N = 10) was supplemented with the same doses as BMT(+). Peroxide concentrations in plasma were measured by using the cholesterol oxidase (CHOD)-iodide method and antioxidants were measured by HPLC. Before supplementation the beta-carotene and alpha-tocopherol concentrations were comparable in both patient groups. After supplementation significantly higher beta-carotene and alpha-tocopherol concentrations were measured in the supplemented patients, BMT(+), than in the unsupplemented patients, BMT(-). After conditioning therapy, BMT(+) patients showed a significantly higher beta-carotene concentration (p < 0.05) than before supplementation. In BMT(-) patients the beta-carotene (p < 0.05) and alpha-tocopherol concentrations (p < 0.01) decreased significantly and the lipid peroxide concentration increased significantly following conditioning therapy. We conclude that antioxidant supplementation prior to conditioning therapy reduces peroxidation processes induced by conditioning therapy in bone marrow recipients.

Adolescent↗
PubMed1997

Cure of Helicobacter pylori infection and duration of remission of low-grade gastric mucosa-associated lymphoid tissue lymphoma.

BACKGROUND: Low-grade B-cell lymphomas arising in mucosa-associated lymphoid tissue (MALT) are most frequently localized in the gastrointestinal tract. More than 90% of gastric MALT lymphomas are diagnosed in patients with chronic, Helicobacter pylori-associated gastritis. High remission rates for these lymphomas have been observed after the cure of H. pylori infection. Data are lacking, however, with regard to the duration of the remissions. To address this question of remission duration, we have followed 50 patients in whom H. pylori infections were eradicated, and we determined whether the patients in complete remission displayed evidence of residual monoclonal B cells during follow-up. METHODS: Patients were treated with amoxycillin and omeprazole for 2 weeks in an attempt to cure H. pylori infections. Follow-up included endoscopic investigations with biopsy sampling. Monoclonal B cells in biopsy specimens were detected by means of a polymerase chain reaction (PCR)-based assay. RESULTS: H. pylori infections were cured in all 50 patients. The median follow-up for the 50 patients is currently 24 months (729 days; range, 135-1411 days). Forty patients achieved complete remission of their lymphomas, but five have subsequently relapsed. The median time of continuous complete remission for the 40 patients was 15.4 months (468 days; range, 0-1198 days). Among six patients whose Iymphomas did not respond to H. pylori eradication, four revealed high-grade lymphomas upon surgery. PCR indicated the presence of monoclonal B cells during follow-up in 22 of 31 assessable patients in complete remission. CONCLUSIONS: Complete remissions of low-grade gastric MALT Iymphomas after the cure of H. pylori infection appear to be stable, although most patients display evidence of monoclonal B cells during follow-up. Whether these patients are truly cured of their Iymphomas remains to be determined.

Adult↗
PubMed1997

[Immune thrombocytopenia, anemia and leukopenia during pregnancy. Successful therapy with extracorporeal immunoadsorption].

HISTORY AND CLINICAL FINDINGS: A 28-year-old woman in her fourth pregnancy had a positive direct Race-Coombs test in her 14th week of pregnancy. About 6 weeks later she developed marked anaemia, severe thrombocytopenia and leukopenia with nose-bleeds as well as petechiae over the lower abdomen and the inguinal regions. INVESTIGATIONS: Platelet count was 7000/microliter, haemoglobin concentration 4.8 mmol/l (7.73 g/dl) and WBC count 2600/microliter). Bleeding time was markedly prolonged. Erythrocyte-attached immunoglobulin G and complement components as well as antithrombocyte and antigranulocyte antibodies were demonstrated. Haemoblastosis or aplastic anaemia was excluded by bone marrow examination. TREATMENT AND COURSE: The pancytopenia with immune thrombocytopenia, autohaemolytic anaemia and associated leukopenia were classified as Evans syndrome. Administration of glucocorticoids and of immunoglobulins intravenously for 5 days failed to improve the blood picture significantly. But platelet count rose significantly on immunoadsorption (Ig Therasorb columns), allowing the pregnancy to proceed. CONCLUSION: In life-threatening states Ig immunoadsorption can achieve well tolerated, effective and specific elimination of pathogenetically relevant antibodies against blood cells and can also be applied in pregnant women.

Adult↗
PubMed1997

Sensitivity of combined DNA/immunophenotype flow cytometry for the detection of low levels of aneuploid lymphoblastic leukemia cells in bone marrow.

By simultaneous DNA staining and immunophenotyping, the aneuploid blasts of acute lymphoblastic leukemia (ALL) can be quantitated by flow cytometry. The present study evaluates the application of this method for the detection of minimal residual disease (MRD). For this purpose leukemia cells with known aneuploidy were serially diluted with diploid bone marrow cells obtained after chemotherapy. These mixed samples were immunophenotyped using antibodies CD34, CD10, or CD19 and processed for DNA staining with propidium iodide. Fifty thousand cells were measured for each experiment and the results were compared with the analysis of control sample without added aneuploid cells. Aneuploid cells diluted to 1% were not detectable in 6/15 cases when DNA content analysis was used alone, and in dilutions of < 1%, these cells were not detectable. When DNA content and immunophenotype were simultaneously measured, aneuploidy was detectable in 15/15 cases at 1.00%, 6/6 at 0.50%, 16/16 at 0.10%, and 16/17 at 0.05%. Therefore this method may be useful for the detection of minimal residual disease in cases of aneuploid lymphoblastic leukemia.

Aneuploidy↗