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Biomedical subjects

K Geissler

Publications and source records attributed to K Geissler.

At least 55 records · Page 3Linked to original sources
PubMed2000

Decrease of circulating hematopoietic progenitor cells During interleukin-2 treatment is associated with an increase of vascular cell adhesion molecule-1, a critical molecule for progenitor cell adhesion.

Administration of interleukin-2 (IL-2) to cancer patients has been shown to transiently decrease the number of circulating hematopoietic progenitor cells, but the mechanism of this phenomenon is unknown. Recently, the interaction of vascular adhesion molecule-1 (VCAM-1) with leukocyte very late antigen-4 (VLA-4) has been demonstrated to play a crucial role in the adhesion of progenitor cells to bone marrow stromal elements. Cytokine induced upregulation of VCAM-1 leads to increased binding of progenitor cells to stromal cells in vitro, and inhibition of this interaction by monoclonal antibodies is associated with marked progenitor cell mobilisation in vivo. In the present study we serially determined peripheral blood progenitor cell numbers during IL-2 treatment (10 courses) in 6 cancer patients and determined in parallel levels of soluble VCAM-1 as a surrogate marker for the in vivo activation of this molecule. Our data indicate that continuous intravenous administration of IL-2 for 5 days leads to a marked decrease of circulating progenitor cells associated with a substantial increase of circulating VCAM-1. Circulating myeloid progenitor cells (CFU-GM) dropped from a mean value of 167 +/- 187 / ml pre IL-2 to 16 +/- 15 / ml on day 3 (p < 0.01). Similarily, mean erythroid progenitors (BFU-E) decreased from 282 +/- 204 / ml before IL-2 administration to 86 +/- 61 / ml on day 3 (p < 0.005). In contrast, soluble VCAM-1 rose from a mean value of 1814 +/- 451 ng/ml before to 4607 +/- 736 ng/ml at the end of IL-2 therapy (p < 0.0001). Sera from IL-2 treated patients did not inhibit hematopoietic colony formation from normal bone marrow. These results suggest redistribution and increased adhesion of progenitor cells to stromal and/or endothelial elements during IL-2 via the VCAM-1/VLA-4 interaction as a possible mechanism for the decrease of circulating progenitor cells during IL-2 therapy.

Adult↗
PubMed2000

[Cytokine combinations for in vivo and ex vivo expansion of hematopoietic progenitor cells].

The critical role of hematopoietic progenitor cells (HPC) for the formation of mature blood cells is well established. Interleukin-3 (IL-3), stem cell factor (SCF), and flt3-ligand (FL) are potential candidates for expansion strategies due to their early acting and lineage-unspecific hematopoietic stimulation. In preclinical and clinical models IL-3, SCF, and FL induced in-vivo expansion of the progenitor cell pool has been shown to be associated with increased HPC-mobilization by G-CSF, reduction in the number of leukaphereses required to obtain adequate HPC-numbers and the potentiation of lineage-specific growth factors. Early acting cytokines are also crucial for ex-vivo expansion strategies and are here important partner molecules for IL-1, IL-6 and IL-10. In-vivo as well as ex-vivo expanded HPC are able to reconstitute hematopoiesis in patients following myeloablative chemoradiotherapy. Thus expanded HPC will be increasingly used for clinical purposes and facilitate therapeutic strategies which are currently limited by the problem of insufficient HPC-numbers.

Animals↗
PubMed1999

Treatment of hairy cell leukemia with cladribine (2-chlorodeoxyadenosine).

Hairy cell leukemia is a rare lymphoproliferative disorder resistant to conventional chemotherapeutic agents. Recently, the purine analogue cladribine (2-chlorodeoxyadenosine, 2-CdA) was introduced for the treatment of this disease. We report on 14 patients with hairy cell leukemia who were treated with 2-CdA at our department between 1993 and 1997. The patients received a single cycle of 2-CdA at a dose of 0.07 or 0.09 mg/kg/day by continuous infusion, over a seven-day period. Five patients were previously untreated, while the others had received prior treatment with interferon-alpha (seven patients), interferon-alpha and splenectomy (one patient) or interferon-alpha, splenectomy and pentostatin (one patient). Six patients achieved complete remission, three a good partial response and three partial remission. Two patients did not respond to treatment and one of them died from septicemia in aplasia. Relapse of the disease occurred in two patients. Side effects such as fever (WHO grade 2) and/or neutropenia (WHO grade 4) were noted in eight patients. Thus, 2-CdA is an effective treatment of hairy cell leukemia that can induce long lasting remissions in both, previously treated and untreated patients.

Adult↗
PubMed1999

Long-term improvement of hematopoiesis following cyclosporine treatment in a patient with myelodysplastic syndrome.

Current treatment of patients with myelodysplastic syndrome (MDS) is unsatisfactory. Very recently, immunosuppressive treatment strategies have been gaining interest. We report a patient with transfusion-dependent MDS who achieved significant hematopoietic improvement following cyclosporine (CsA) therapy and who is now transfusion independent for more than 5 years. This single observation supports the view that CsA, among other immunosuppressive agents, could play an important role in future treatment concepts in MDS and may lead to clinically relevant and sustained improvement of hematopoiesis in a subset of patients.

Adult↗
PubMed1999

[Polycythaemia vera--diagnosis and therapy].

Polycythaemia vera is a clonal myeloproliferative disorder mainly involving proliferation of the erythropoiesis. The symptoms are varied and usually unspecific. The most serious complications of the disease are a thrombotic tendency and myeloid metaplasia. Thromboses mainly (2/3) occur in the arterial and less often (1/3) in the venous system and are the most common cause of death. Criteria have been established for the diagnosis of polycythaemia vera which should be strictly observed in order to distinguish between this disease, spurious polycythaemia, essential thrombocythaemia and secondary erythrocytosis. The goal of treatment is the prevention of thromboembolic complications and of myeloid metaplasia. The initial treatment always consists of phlebotomies until a hematocrit < 45% is achieved. The decision regarding maintenance therapy is difficult. While hydroxyurea or radiophosphorus is the treatment of choice in older patients (> 70 years of age), it is more difficult to select the appropriate therapy for younger patients (< 60 years), since recent studies have indicated that hydroxyurea treatment might increase the risk of leukemia. Interferon is effective but its role in the treatment of polycythaemia vera has not been established.

Humans↗
PubMed1999

Characterisation of a potentially abortigenic strain of feline calicivirus isolated from a domestic cat.

Feline calicivirus (FCV) was isolated from one of four dead fetuses delivered by ovariohysterectomy from a queen with an acute FCV infection. The most prominent lesions in the fetuses were petechial haemorrhages in the skin. The virus isolated was characterised as FCV by antigenic analysis and cDNA sequence analysis. This is the second report of abortion associated with acute FCV infection.

Abortion, Veterinary↗
PubMed1999

Activity of phase I and phase II detoxication enzymes in different cormus parts of Phragmites australis.

Enzymes of phase I and phase II of the xenobiotic detoxication pathway (ethoxyresorufin-O-deethylase, peroxidases, microsomal and soluble glutathione-S-transferases) were measured in roots, stems, and leaves of Phragmites australis, revealing different enzyme activities in these parts. Highest enzyme activities were measured in the root followed by the leaf. Enzyme activities detected in the stem were low compared with those in the root and leaf. The high detoxication capacity of the root and the leaf might be due to very high exposure to xenobiotics and to the high levels of metabolism in these cormus parts. The function of the stem of Phragmites is mainly transportation, so a high detoxication level is not useful, as indicated by the low enzyme activities.

Cytochrome P-450 CYP1A1↗
PubMed1999

The lung resistance protein (LRP) predicts poor outcome in acute myeloid leukemia.

To determine the clinical significance of the lung resistance protein (LRP) in acute myeloid leukemia (AML), we have studied LRP expression of leukemic blasts and its association with clinical outcome in patients with de novo AML. LRP expression of leukemic blasts was determined by immunocytochemistry by means of monoclonal antibody LRP-56. LRP expression at diagnosis was detected in 31 out of 86 (36%) patients and correlated with white blood cell count (p = 0.01). The complete remission rate of induction chemotherapy was 72% for all treated patients (n = 82). The complete remission rate was 81% for patients without LRP expression but only 55% for patients with LRP expression (p = 0.01). Overall survival and disease-free survival were estimated according to Kaplan-Meier in 82 and 59 patients, respectively. At a median follow-up of 16 months, median overall survival was 17 months for LRP-negative patients but only 8 months for LRP-positive patients (p = 0.006). Disease-free survival was 9 months for LRP-negative patients and 6 months for LRP-positive patients (p = 0.078). Thus LRP predicts for poor outcome indicating that the LRP gene is a clinically relevant drug resistance gene in AML.

Adolescent↗
PubMed1999

Granulocyte colony-stimulating factor-supported combined immunosuppressive therapy (antilymphocyte globulin, cyclosporine, and methylprednisolone) in patients with aplastic anemia: tolerability, efficacy, and changes in the progenitor cell compartment.

Neutropenic infections are the major cause of morbidity and mortality in the treatment of aplastic anemia (AA) with antilymphocyte globulin (ALG), cyclosporin A (CSA), and methylprednisolone (MP). Recent data suggest a beneficial effect of administering G-CSF as an adjunct to immunosuppression. We have treated 11 consecutive patients with AA using a combined immunosuppressive regimen including ALG, CSA, and MP plus G-CSF at a dose of 5 microg/kg/day until neutropoietic recovery. In addition to measuring routine hematological parameters we have performed serial determinations of reticulocyte counts and in vitro progenitor cell cultures before and after therapy in order to assess their predictive value for treatment response and to determine the impact of therapy on early hematopoiesis. One patient died on day 34 of neutropenic septicemia. At 1 year, 81% of patients showed response to treatment. The median time to ANC values >0.5 and >1.0 x 10(9)/l were 19 and 35 days, respectively. Reticulocyte counts started to recover after 6 weeks, and transfusion independence was observed on day 52 for red blood cell transfusions and on day 53 for platelet concentrates. All patients with detectable colony formation in peripheral blood achieved a complete hematological remission, as compared with only one of five patients without progenitor cell growth. Although normal ranges were rarely achieved, there was a small but definitive improvement in progenitor cell numbers as compared with baseline values in most patients. Our results confirm the good tolerability and high efficacy of this G-CSF-supported combined immunosuppressive therapy for AA. Detectable colony growth at diagnosis seems to predict a high chance for complete hematological response.

Adult↗
PubMed1999

Successful treatment with arsenic trioxide of a patient with ATRA-resistant relapse of acute promyelocytic leukemia.

Arsenic trioxide has recently been introduced as a promising new agent to treat refractory acute promyelocytic leukemia (APL). In the present study, arsenic trioxide was given intravenously for 42 days to a 56-year-old female patient suffering from chemotherapy/ATRA-resistant APL, with 43% APL blasts in the bone marrow and elevated D-dimers. During the first days of arsenic trioxide treatment a rapid decrease in the D-dimers was seen (normal values reached until day 7), together with a slight decrease in peripheral blood leukocytes. This initial coagulation response was followed by a second phase of hematological response (starting on days 15-20) characterized by leukocytosis, occurrence of myeloid progenitor cells in the peripheral blood, and a decrease in bone marrow blasts (<1% on days 28 and 36). Finally, the patient entered complete hematological and cytogenetic remission, although the PML-RAR alpha fusion product was still detectable by PCR. These data confirm the therapeutic value of arsenic trioxide in relapsed/resistant APL.

Antineoplastic Agents↗
PubMed1999

Long-term follow-up of patients after related- and unrelated-donor bone marrow transplantation for chronic myelogenous leukemia.

Between January 1983 and December 1997, 88 patients (36 female, 52 male, median age 37 years, range 19-57) with chronic myelogenous leukemia (CML) underwent allogeneic bone marrow transplantation (BMT) at the University Hospital of Vienna. Sixty patients were in chronic phase, 18 in accelerated phase, and ten in blast crisis. Marrow donors were HLA-identical siblings for 64 patients (BM 58, PBSC 6), 2-antigen-mismatched related donors (RD) for two, HLA-identical unrelated donors (URD) for 17, and 1-antigen-mismatched URD for five. The median time from diagnosis to BMT was 22 months (range 2-91), and 63 patients had received prior interferon (IFN)-alpha therapy, 46 (73%) for more than 6 months. Conditioning therapy consisted of cyclophosphamide (CY) and total body irradiation (TBI) in 71 patients and CY and busulfan (BU) in 16. One patient received etoposide and TBI. For graft-versus-host disease (GVHD) prophylaxis methotrexate (MTX) was given to 12 patients, MTX and cyclosporin A (CSA) to 67, CSA alone to four, and CSA and methylprednisolone to five. Durable engraftment was documented in 80 of 82 patients (98%). As of December 31, 1997, 52 patients (59%) were alive, 38 (58%) after sibling transplantation with a median observation time of 73 months and 14 (64%) after URD transplantation with a median observation time of 12 months. Probability of overall survival is 59%, for patients undergoing transplantation in chronic phase and 44% for patients undergoing transplantation in advanced stage CML. Probability of disease-free survival (DFS) after sibling and URD BMT is 55% and 59%, respectively. Ten patients (12%) experienced relapse of CML. Transplant-related mortality was 32% both after RD and after URD transplantation. Acute GVHD occurred in 53 of 80 evaluable patients (66%), consisting of grade III or IV in 14 patients (18%). Chronic GVHD developed in 40 of 63 eligible patients (63%), including extensive disease in 26 patients (41%). Thus, sibling and URD BMT offer high cure rates with acceptable toxicity to patients with CML.

Acute Disease↗
PubMed1999

Interleukin-10 inhibits burst-forming unit-erythroid growth by suppression of endogenous granulocyte-macrophage colony-stimulating factor production from T cells.

Numerous cytokines released from accessory cells have been shown to exert either stimulatory or inhibitory growth signals on burst-forming unit-erythroid (BFU-E) growth. Because of its cytokine synthesis-inhibiting effects on T cells and monocytes, interleukin-10 (IL-10) may be a potential candidate for indirectly affecting erythropoiesis. We investigated the effects of IL-10 on BFU-E growth from normal human peripheral blood mononuclear cells (PBMC) using a clonogenic progenitor cell assay. The addition of recombinant human IL-10 to cultures containing recombinant human erythropoietin suppressed BFU-E growth in a dose-dependent manner (by 55.2%, range 47.3-63.3%, p < 0.01, at 10 ng/mL). In contrast, no inhibitory effect of IL-10 was seen when cultivating highly enriched CD34+ cells. BFU-E growth from PBMC also was markedly suppressed in the presence of a neutralizing anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody (by 48.7%, range 32.9-61.2% inhibition,p < 0.01), but not by neutralizing antibodies against granulocyte colony-stimulating factor and interleukin-3. This suggests a stimulatory role of endogenously released GM-CSF on BFU-E formation. Also, the addition of exogenous GM-CSF completely restored IL-10-induced suppression of BFU-E growth. To determine the cellular source of GM-CSF production, we analyzed GM-CSF levels in suspension cultures containing PBMC that were either depleted of monocytes or T cells. Monocyte-depleted PBMC showed spontaneous production of increasing amounts of GM-CSF on days 3, 5, and 7, respectively, which could be suppressed by IL-10, whereas GM-CSF levels did not increase in cultures containing T-cell-depleted PBMC. Our data indicate that IL-10 inhibits the growth of erythroid progenitor cells in vitro, most likely by suppression of endogenous GM-CSF production from T cells.

Cells, Cultured↗
PubMed1999

Quantification of minimal residual disease in patients with BCR-ABL-positive acute lymphoblastic leukaemia using quantitative competitive polymerase chain reaction.

We analysed 20 patients with BCR-ABL-positive acute lymphoblastic leukaemia (ALL) by quantitative competitive polymerase chain reaction (QC-PCR) to study the kinetics of the leukaemic clone. Consecutive samples of 16 patients (minor-bcr, n = 10; major-bcr, n = 6) were analysed after conventional chemotherapy and/or bone marrow transplantation (BMT). DNA competitor templates co-amplifying with either p210 or p190 BCR-ABL cDNA were used for quantification of leukaemia-specific BCR-ABL mRNA. In all samples, total ABL transcripts were measured as internal control, and the percentage of BCR-ABL/ABL molecules was calculated. Following induction chemotherapy the number of BCR-ABL transcripts was reduced by a maximum of 2-3 logs. In most patients, additional chemotherapy did not lead to further reduction of BCR-ABL mRNA. In two patients, conventional chemotherapy plus autologous BMT in complete haematological remission resulted in a total reduction of the transcript level of more than 3 logs. In two other patients, allogeneic BMT caused a transient reduction of the BCR-ABL transcripts below the detection level of our method (<1 blast cell in 105 normal cells) for a period of 7 and 11 months, respectively. The achievement of PCR negativity did not guarantee sustained remission. Both patients relapsed and BCR-ABL transcript levels rose by more than 1 log prior to frank relapse. Our data demonstrate that quantification of BCR-ABL mRNA allows the evaluation of the dynamics of the leukaemic clone and thus is valuable for the evaluation of minimal residual leukaemia following various therapies and the early detection of increasing BCR-ABL transcripts prior to relapse.

Adult↗
PubMed1999

Clonality analysis using X-chromosome inactivation at the human androgen receptor gene (Humara). Evaluation of large cohorts of patients with chronic myeloproliferative diseases, secondary neutrophilia, and reactive thrombocytosis.

Chronic myeloproliferative diseases (MPDs) are not associated with consistent cytogenetic or molecular abnormalities. Demonstration of clonal cell growth by analysis of X-chromosome inactivation (XCI) patterns in females provides a promising tool for diagnosis. However, this technique can be complicated by excessive lyonization of normal cells mimicking clonal cell growth: We analyzed XCI patterns at the human androgen receptor (HUMARA) locus in 146 healthy females, 65 women with secondary neutrophilia, 31 women with reactive thrombocytosis, and 86 women with chronic MPDs. A skewed XCI pattern with greater than 75% amplification of 1 allele (allele ratio > 3:1) was found in 22 (9.1%) of 242 control subjects. The incidence of skewing was statistically significantly lower in women younger than 30 years (2/73) compared with women older than 60 years (10/53). Of 86 patients with a chronic MPD, 71 (82%) exhibited an allele ratio greater than 3:1, whereas only 10 (12%) of 86 age-matched control subjects showed a skewed XCI pattern. Although statistical evaluation of the data showed a significant difference between patients with a chronic MPD and control subjects, proof of clonality in individual, especially elderly, patients is difficult.

Adolescent↗
PubMed1999

The proportion of reticulated platelets is higher in bone marrow than in peripheral blood in haematological patients.

Since the detection that platelets originate from megakaryocytes (MK), the site of megakaryocyte fragmentation has been disputed. Some authors have even postulated that platelets are solely produced in the lungs. Thus, we have directly measured platelet generation in the bone marrow (BM) by comparing the relative number of young RNA-containing, so-called reticulated platelets (%RP) in the BM and in the peripheral blood (PB). Two separate prospective, cross sectional trials have been conducted in patients routinely undergoing BM biopsies for diagnostic purposes. In the first part of the study 30 patients with stem cell or bone marrow transplantation were examined. The second part of the study was performed in 62 haematological patients visiting the outpatient's clinic. Median %RP were higher in BM than in PB (p <0.001). In the second part of the study the difference averaged 133% (interquartile range: 30-383%). There was a moderate correlation between %RP in BM and in PB (r = 0.67; p <0.001). The absolute number of RP in PB correlated weakly with the number of megakaryocytes (0.42; p = 0.001), which was due to a correlation between the platelet counts and the megakaryocyte counts (r = 0.55; p <0.001 in biopsies). Two patients with autoimmune antibodies against GPIIb/IIIa exhibited 10% and 16% RP in PB, and had 29% and 59% RP in BM, respectively. It is concluded that the relative number of RP is significantly higher in BM than in blood. This supports the notion that platelets are at least in part released from MK in the bone marrow, particularly in patients suffering from immune thrombocytopenia.

Antigens, Surface↗
PubMed1999

Feline calicivirus capsid protein expression and capsid assembly in cultured feline cells.

The capsid protein of feline calicivirus (FCV) was expressed by using plasmids containing cytomegalovirus, simian virus 40, or T7 promoters. The strongest expression was achieved with the T7 promoter and coinfection with vaccinia virus expressing the T7 RNA polymerase (MVA/T7pol). The FCV precursor capsid protein was processed to the mature-size protein, and these proteins were assembled in to virus-like particles.

Animals↗
PubMed1999

Dose dependent reduction of erythroid progenitor cells and inappropriate erythropoietin response in exposure to lead: new aspects of anaemia induced by lead.

OBJECTIVE: To determine whether haematopoietic progenitor cells and erythropoietin (EPO), which is an essential humoral stimulus for erythroid progenitor (BFU-E) cell differentiation, are affected by lead intoxication. METHODS: In male subjects chronically exposed to lead with and without anaemia, pluripotent (CFU-GEMM), BFU-E and granulocyte/macrophage (CFU-GM) progenitor cell counts in peripheral blood were measured with a modified clonal assay. Lead concentrations in blood (PbB) and urine (PbU) were measured by the atomic absorption technique, and EPO was measured with a modified radioimmunoassay. RESULTS: PbB in the subjects exposed to lead ranged from 0.796 to 4.4 mumol/l, and PbU varied between 0.033 and 0.522 mumol/l. In subjects exposed to lead with PbB > or = 2.896 mumol/l (n = 7), BFU-E cells were significantly reduced (p < 0.001) whereas the reduction in CFU-GM cells was only of borderline significance (p = 0.037) compared with the age matched controls (n = 20). The CFU-GEMM cells remained unchanged. Furthermore, BFU-E and CFU-GM cells were reduced in a dose dependent fashion, with increasing PbB or PbU, respectively. In the subjects exposed to lead EPO was in the normal range and did not increase in the presence of anaemia induced by lead. No correlations existed between EPO and PbB, PbU, or progenitor cells. CONCLUSION: The data suggest new aspects of lead induced anaemia besides the currently acknowledged shortened life span of erythrocytes and inhibition of haemoglobin synthesis. Two additional mechanisms should be considered: the reduction of BFU-E cells, and inappropriate renal EPO production in the presence of severe exposure to lead, which would lead to an inadequate maturation of BFU-E cells.

Adult↗