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Biomedical subjects

K Lechner

Publications and source records attributed to K Lechner.

At least 217 records · Page 12Linked to original sources
PubMed1993

Granulocyte colony-stimulating factor (rh G-CSF) as an adjunct to interferon alpha therapy of neutropenic patients with hairy cell leukemia.

Six patients with hairy cell leukemia (HCL) and neutropenia (median neutrophil count 563/microliters, range 30-1200) were treated with recombinant human granulocyte colony-stimulating factor (G-CSF) at a dose of 5 micrograms/kg by daily subcutaneous injection as an adjunct to interferon-alpha (IFN-a) therapy, in order to ameliorate neutropenia. Five of six patients responded to G-CSF with normalization of neutrophil counts (> 1800/microliters) within 2-11 days and a median neutrophil count of 5211/microliters (range 4312-10160) at the end of G-CSF therapy. In three of these patients, infections resolved when neutropoiesis recovered. In one patient with very severe neutropenia (30/microliters), in whom myeloid progenitors were not detectable, G-CSF therapy failed to restore granulopoiesis. Cessation or interruption of G-CSF after 2-5 weeks of therapy resulted in a rapid decline of neutrophil counts to lower or subnormal levels (median value 1478/microliters, range 770-2739) within 1 week, suggesting that the improvement of granulopoiesis was dependent on G-CSF and not due to IFN-a therapy. G-CSF may be a useful adjunct to IFN-a therapy in patients with HCL in order to manage or prevent neutropenic complications in the early phase of treatment.

Adult↗
PubMed1993

Treatment of drug-induced agranulocytosis with recombinant granulocyte colony-stimulating factor (rh G-CSF).

Five patients with drug-induced agranulocytosis received 300 micrograms recombinant human granulocyte colony-stimulating factor (rh G-CSF) subcutaneously twice daily for 2-5 days. G-CSF therapy resulted in a steep increase of the neutrophil count, which was faster than that in patients with spontaneous recovery reported in the literature. In all four patients with infectious complications fever rapidly declined with the increase of granulocytes. G-CSF may be useful in the management of drug-induced agranulocytosis.

Adult↗
PubMed1993

Transient lupus anticoagulant associated with hypoprothrombinemia and factor XII deficiency following adenovirus infection.

A potent lupus anticoagulant (LA) was detected in four children, 1 week after the clinical onset of an adenovirus infection. The adenovirus infection was documented by direct virus detection in the stool of one patient and serologically in the others. None of the children had elevated titers of IgM- and only one of IgG-anticardiolipin antibodies (ACA). All patients had a marked reduction of prothrombin activity as well as antigen. Prothrombin-antibody complexes were demonstrated in the patients' plasma or mixtures of patient and normal plasma. Factor XII activity was moderately reduced in three of the patients. All coagulation abnormalities returned to normal within 4-12 weeks. Localized bleeding was observed in two cases, but there was no generalized bleeding tendency or evidence of thrombosis.

Adenoviridae Infections↗
PubMed1993

Induction of specific histamine release from basophils with purified natural and recombinant birch pollen allergens.

As much as 15% of the population in industrialized countries suffers from type I allergic symptoms (rhinitis, conjunctivitis, and bronchial asthma). One approach toward this disease involves the production of recombinant allergens in Escherichia coli and their purification for diagnostic and therapeutic purposes. In this study we compared the IgE-binding capacity of natural and recombinant birth allergens with their functional ability to release histamine from allergic patients' basophils via cross-linking of high-affinity Fc epsilon-receptors. The recombinant as well as pollen-derived Bet v I and birch profilin (Bet v II) were purified and tested in parallel on IgE immunoblots and in in vitro histamine release tests (n = 21). We observed an excellent correlation between allergen-induced histamine release and birch pollen RAST (r = 0.881, p < 0.002). Nonspecific histamine release as a result of a cell toxic effect of the allergen preparations was never observed from basophils of donors without birch pollen allergy. The specificity of the presented effector model is also documented by the specific desensitization of patients' basophils with the recombinant allergens. These data may provide a basis for the use of purified recombinant allergens in sensitive and specific in vitro allergy tests monitoring the effector situation in allergic patients, which therefore may represent a possible alternative for in vivo diagnostic methods.

Allergens↗
PubMed1993

Specific activation of human mast cells by the ligand for c-kit: comparison between lung, uterus and heart mast cells.

Recent data suggest that stem cell factor (SCF or c-kit ligand, KL) is a major regulator of human mast cells (MCs). In the present study, MCs derived from the lung (n = 8), uterus (n = 14) and heart (n = 4) were analyzed for expression of c-kit receptor and for responses to recombinant SCF. MCs of all organs tested were recognized by mAbs to c-kit (YB5.B8, SR-1) as assessed by combined toluidine blue/immunofluorescence staining. Activation by rhSCF (10 ng/ml, 60 min) resulted in histamine release from lung MCs (SCF 12.8 +/- 2.7% histamine release; control 2.8 +/- 0.8%, p < 0.01), uterus MCs (SCF 16.8 +/- 5.8%; control 5.2 +/- 2.5%, p < 0.01) and heart MCs (SCF 18.4 +/- 2.6%; control 1.7 +/- 0.23%, p < 0.01). Short-term pre-incubation with rhSCF (15 min) did not result in histamine secretion (p > 0.05), but in an increase (lung 2.4 +/- 1.0 fold; uterus 2.1 +/- 1.1 fold, and heart 2.0 +/- 0.4 fold) of alpha IgE-induced mediator release (p < 0.05). The effects of SCF were dose-dependent (maximum responses at 10-100 ng/ml) and dependent on extracellular calcium. A monoclonal antibody to SCF was found to inhibit the effects of SCF on MCs. Furthermore, MCs could be desensitized specifically by pre-incubation of MCs with rhSCF in Ca-free medium. Together, these data suggest that SCF triggers mediator secretion from MCs in various organs via binding to the c-kit receptor.

Antibodies, Monoclonal↗
PubMed1993

Immunoreactive inhibin in human follicular fluid in an ovarian hyperstimulation programme for in vitro fertilization: correlations and different forms.

UNLABELLED: The inhibin concentration in 131 samples of human follicular fluid obtained from 31 women undergoing ovarian hyperstimulation for in vitro fertilization was measured using specific double antibody radioimmunoassay. We used the synthetic 1-32-alpha-inhibin as standard and radioiodinated 1-32-Tyr-alpha-inhibin as tracer. Antibodies were raised in rabbits by immunization with the synthetic peptide. Estradiol and progesterone concentrations were measured using commercial radioimmunoassays. RESULTS: The inhibin concentration correlated with the estradiol (r = 0.57, N = 88, p < 0.0001) and progesterone (r = 0.82, N = 88, p < 0.0001) concentrations in human follicular fluid. The dosage of human menopausal gonadotropin given to individual patients correlated with the average inhibin concentration measured in their follicles (r = 0.72, N = 23, p < 0.0001). Similarly, the size of follicles correlated with their inhibin content (r = 0.75, N = 131, p < 0.0001). Nineteen samples of human follicular fluid originating from follicles of different size and volume were examined using gel-chromatography. In each human follicular fluid the main form of inhibin (32 kDa) was recovered. In small follicles (3 ml) we found 12.8 +/- 9.1% (mean +/- SD) of the whole immunoreactive inhibin eluting in the area of Vo (> or = 80 kDa). In the larger follicles (4-7 ml), however, only 4.4 +/- 4.2% of this large inhibin form could be found. CONCLUSIONS: Our data confirm that human menopausal gonadotropin stimulates ovarian inhibin production. In addition to the estradiol and progesterone concentrations, the inhibin concentration may be an index of granulosa cell function and follicular maturation. The occurrence of large molecular weight forms of inhibin in small follicles remains unclear. They may represent large precursor molecules which are proteolytically cleaved in more mature follicles.

Adult↗
PubMed1993

MDR1 RNA expression as a prognostic factor in acute myeloid leukemia: an update.

In order to confirm our initial report on the negative impact of MDR1 gene expression on the outcome of de novo acute myeloid leukemia (AML), we present an update of our prospective study with a larger number of patients and a longer duration of follow-up. At diagnosis, MDR1 RNA expression of the leukemic cells was negative in 37% and positive in 63% of the patients (N = 79). The complete remission rate of induction chemotherapy was 76% for MDR1 RNA negative and 54% for MDR1 RNA positive patients (p = 0.05). At a median observation duration of 33 months, the duration of overall survival was 19 months for the MDR1 RNA negative patients but only 8 months for the patients with MDR1 gene expression (p = 0.02). Thus the long-term data also indicate that MDR1 gene expression is an unfavourable prognostic factor in AML.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

[Mobilization of circulating hematopoietic stem cells by granulocyte colony stimulating factor after chemotherapy in multiple myeloma].

Due to the relatively low tumour cell contamination of peripheral blood in patients with multiple myeloma, autologous transplantation of circulating stem cells may have theoretical advantages over autologous bone marrow transplantation. In four patients with multiple myeloma who where considered potential candidates for autologous stem cell transplantation G-CSF (600 micrograms/day) was administered following chemotherapy in order to maximally increase the number of circulating progenitor cells during haematopoietic rebound and to facilitate progenitor cell harvest by leukapheresis. In two previously untreated patients the administration of G-CSF following chemotherapy according to the UVA protocol (ultralan, vincristine, adriamycin) greatly increased circulating haematopoietic stem cells from 247 to 7552 CFU-GM/ml in patient 1 and from 173 to 6361 CFU-GM/ml in patient 2, which by far exceeded the increase in progenitor cells following chemotherapy alone, namely only to 594 and 317 CFU-GM/ml in patient 1 and patient 2, respectively. In two repeatedly pretreated patients, the combination of UVA and G-CSF was much less effective. Progenitor cells increased from 144 to 735 CFU-GM/ml in patient 3 and only from 222 to 232 CFU-GM/ml in patient 4. In both cases, however, mobilization of haematopoietic progenitor cells by G-CSF following cyclophosphamide (50 and 70 mg/kg body weight, respectively) led to much higher CFU-GM peak values (5324 in patient 3 and 2245 in patient 4), thus allowing an adequate harvest of mononuclear cells and CD 34+ cell numbers to achieve, in all probability, the prompt and complete reconstitution of haematopoiesis in case of transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1993

[Effector cells in allergy: biological principles and new pharmacologic concepts].

The clinical symptoms of allergy are caused by cellular (IgE-triggered) responses to an allergen. Effector cells of allergy include eosinophil and basophil granulocytes, as well as tissue mast cells. Growth and accumulation, as well as IgE-dependent and independent functions of these cells are regulated by distinct proteohormones and peptides. The hemopoietic cytokines IL-3 (interleukin-3), IL-5 and GM-CSF (granulocyte-macrophage colony-stimulating factor) are involved in the regulation of basophils (and eosinophils), whereas the ligand for c-kit, SCF (stem cell factor) is a mast cell-specific agonist. Basophils and mast cells express high-affinity IgE-binding sites. Allergen binding to IgE on mast cells and basophils, and consecutive cross-linking of IgE receptors is followed by production and/or secretion of inflammatory mediator substances. Specific activation and deactivation of mast cells/basophils in vitro has been demonstrated by use of recombinant cytokines and allergens, and specific haptens or by use of novel drugs, and should lead to epitope-specific diagnosis and better management of allergic diseases in the future.

Allergens↗
PubMed1993

Intravenous pentoxifylline failed to prevent transplant-related toxicities in allogeneic bone marrow transplant recipients.

Based on encouraging results of a recently published study on the clinical usefulness of oral pentoxifylline (PTX) to reduce transplant-related toxicities, prophylactic pentoxifylline was administered to 31 consecutive allogeneic BMT recipients with hematological malignancies. Patients received PTX as a continuous infusion at increasing dose levels (0.50, 0.75, 1.00 and 1.25 mg/kg/h) starting 1 day prior to the conditioning regimen. At all dose levels, PTX was well tolerated with no significant side-effects. When compared with a historical control group of 61 consecutively transplanted allogeneic BMT recipients, PTX patients did not appear to experience less gastrointestinal (moderate and severe mucositis: 100% vs 68%, p < 0.001), hepatic (hyperbilirubinemia > 1.5 mg/dl: 84% vs 30%, p < 0.001) or renal (creatinine > 1.5 mg/dl: 16% vs 27%, NS) toxicity or to have a lower incidence of GVHD > or = grade III (21% vs 22%, NS). Using i.v. PTX, we were unable to reproduce the reduction in morbidity and mortality in patients undergoing BMT which has been described for prophylactic oral PTX.

Adolescent↗
PubMed1993

Tumor necrosis factor alpha and interleukin-1 beta mRNA expression in HMC-1 cells: differential regulation of gene product expression by recombinant interleukin-4.

Cytokine-activation pathways in mast cells are supposed to play a significant role in host defense mechanisms and allergic reactions. Interleukin-4 (IL-4) is a well-characterized regulator of growth and function of mast cells. The human mast cell line HMC-1 was established from a patient suffering from mast cell leukemia and was shown to expose IL-4 binding sites. In the present study, the effects of recombinant human (rh) IL-4 and other rh cytokines (IL-2, IL-3, IL-6, IL-8) on expression of cytokine mRNA in HMC-1 cells were examined by Northern blot analysis using oligonucleotide probes. Tumor necrosis factor alpha (TNF-alpha) and IL-1 beta transcripts were found to be expressed constitutively in HMC-1 cells, whereas transcripts for IL-3, IL-4, IL-5, IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF) could not be detected. Of all cytokines tested, rhIL-4 was found to down-regulate IL-1 beta mRNA expression and formation of immunoreactive IL-1 beta protein in HMC-1 cells. The effect of IL-4 on IL-1 beta gene product expression was time- and dose-dependent (maximum effects obtained with 100 U/mL of rhIL-4). No effect of IL-4 on expression of TNF-alpha mRNA in HMC-1 cells was observed. These results raise the possibility that human mast cells are a source of both TNF-alpha and IL-1 beta. Furthermore, our study provides evidence that IL-4 regulates IL-1 beta gene product expression in HMC-1 cells. The HMC-1 cell line should be a useful tool for studying cytokine activation pathways in human mast cells.

Base Sequence↗
PubMed1993

Postpartum factor VIII inhibitors. Report of two cases with special reference to the efficacy of various treatments.

Two cases of postpartum inhibitors to F VIII are described. One patient had a severe bleeding tendency (iliopsoas bleeding, forearm bleeding). The maximum inhibitor titer was 800 BU/ml in case 1 and 120 BU/ml in case 2. Bleeding was controlled by treatment with human and porcine factor VIII concentrate and with activated prothrombin complex concentrate (FEIBA, Immuno AG, Vienna, Austria) in case 1, while no replacement therapy was given in case 2. Prednisone (given in both cases) and high-dose immunoglobulin (given in case 2) was without effect. Cyclophosphamide (100 mg per day), combined with small doses of prednisone led to complete disappearance of the inhibitor and normalization of factor VIII in case 1. In the other patient who refused treatment with cyclophosphamide the inhibitor titer remained high over a period of 13 months.

Adult↗
PubMed1992

Recurrent, isolated factor X deficiency in myeloma: repeated normalization of factor X levels after cytostatic chemotherapy followed by late treatment failure associated with the development of systemic amyloidosis.

We describe the case of a 64-year-old woman with isolated severe factor X deficiency associated with kappa light chain myeloma. At the time of diagnosis there was no evidence for amyloidosis. Complete remission (CR) of myeloma as well as normalization of factor X levels were achieved after cytostatic chemotherapy. Subsequently, factor X deficiency recurred twice without any evidence for relapse of myeloma. The first time factor X normalized again following cytostatic treatment, the second time, however, factor X deficiency was refractory to chemotherapy. Finally, relapse of myeloma became evident associated with rapidly progressing, systemic amyloidosis, which was fatal within a few months. Initially, factor X infusion studies showed a normal recovery, but when amyloidosis became overt the recovery decreased to 0%. We assume that factor X deficiency was due to a binding of factor X to kappa light chains associated with the proliferation of the malignant myeloma cell clone.

Amyloidosis↗
PubMed1992

Induction of differentiation of human mast cells from bone marrow and peripheral blood mononuclear cells by recombinant human stem cell factor/kit-ligand in long-term culture.

In the murine system, a number of cytokines (including interleukin-3 [IL-3], IL-4, and stem cell factor [SCF]) promote the growth of mast cells (MCs). However, so far little is known about factors controlling differentiation of human MCs. Recent data suggest that human MCs express receptors (R) for SCF. The aim of the present study was to investigate whether recombinant human (rh) SCF induces differentiation of human MCs from their precursor cells. For this purpose, bone marrow (BM; normal donors, n = 6) and peripheral blood (PB; normal donors, n = 11) mononuclear cells (MNC) were cultured in the presence of rhSCF, rhIL-3, rhIL-4, rhIL-9, recombinant human macrophage colony-stimulating factor (rhM-CSF), or control medium in long-term (8 weeks) suspension cultures. After 4 weeks, up to 5% of the MNC (BM and PB) cultured in the presence of rhSCF, but not in the presence of other cytokines, were found to exhibit the characteristics of MCs. These MCs expressed the YB5.B8-reactive domain of the SCF R as well as IgE R, as determined by combined toluidine blue/immunofluorescence staining. Myeloid antigens, likewise expressed on human basophils (ie, CD11b, CDw65, and Bsp-1), could not be detected on these cells. Furthermore, rhSCF, but not rhIL-3, rhIL-4, rhIL-9, or rhM-CSF, induced dose- and time-dependent increases in the formation of cellular tryptase (an MC-specific enzyme) (rhSCF [100 ng/mL], 1,308 +/- 679 ng/mL v control medium, 18 +/- 6 ng/mL tryptase on day 35 of PB cell cultures), as well as an increase in cellular histamine. After 6 to 8 weeks, when other mature hematopoietic cells decreased, MCs still could be detected in culture, with up to 40% of all cells being MCs. To test whether rhSCF also activates tissue MCs, we performed histamine release experiments (dispersed tissue; lung, n = 3; uterus, n = 3). SCF was found to enhance (by up to 3.4-fold) the capacity of the MCs to release histamine upon cross-linkage of IgE R with anti-IgE. Together, these observations suggest that rhSCF induces in vitro differentiation of human MCs from their BM and PB precursor cells in long-term culture and upregulates MC releasability.

Antibodies, Monoclonal↗
PubMed1992

Type beta transforming growth factors promote interleukin-3 (IL-3)-dependent differentiation of human basophils but inhibit IL-3-dependent differentiation of human eosinophils.

Basophils and eosinophils share a common differentiation pathway. Factors regulating terminal commitment toward one cell type, however, have so far not been defined. Interleukin-3 (IL-3) is a potent differentiation factor for both human eosinophils and basophils. In the present study, the effects of various recombinant human (rh) growth regulators on IL-3-dependent growth of eosinophils and basophils were studied in a bone marrow (BM) suspension culture system (normal donors, n = 13). We found that type beta transforming growth factors (TGFs) lead to a significant increase in the absolute numbers of basophils in BM cultures grown in the presence of IL-3 (day 14 of culture; IL-3: 133 +/- 20 v IL-3 + TGF-beta 1: 231 +/- 28 x 10(3)/mL [P less than .01]) and to an increase in the total histamine values (IL-3: 72.6 +/- 22.2 v IL-3 + TGF-beta 1: 142.9 +/- 37.3 ng/mL [P less than .015]) compared with rhIL-3 alone. In contrast, type beta TGFs were found to inhibit the IL-3-dependent growth of eosinophils (IL-3: 170.4 +/- 37.2 v IL-3 + TGF-beta 1: 16.7 +/- 5.2 x 10(3)/mL [P less than .01]) and formation of eosinophil cationic protein in the same culture system. The effect of TGF-beta 1 (and TGF-beta 2) on IL-3-dependent differentiation of basophils and eosinophils was dose- and time-dependent (maximum effects observed with 1 to 10 ng/mL of rhTGF-beta 1 or TGF-beta 2) and could be neutralized by an antibody specific for TGF-beta 1. In contrast to the TGFs, interferon-alpha (IFN-alpha) and IFN-gamma were found to downregulate IL-3-dependent formation of both basophils (IL-3: 167 +/- 33 v IL-3 + IFN-alpha: 67 +/- 25 v IL-3 + IFN-gamma: 65 +/- 33 x 10(3)/mL [P less than .01]) and eosinophils (IL-3: 239 +/- 5 v IL-3 + IFN-alpha: 81 +/- 4 v IL-3 + IFN-gamma: 67 +/- 17 x 10(3)/mL [P less than .05]) in our culture system. Type beta TGFs as well as the IFNs failed to directly induce differentiation of human basophils or eosinophils in the absence of other growth factors. Together, these results show that type beta TGFs and IFNs are potent regulators of cytokine-dependent growth and differentiation of human allergic effector cells.

Antibodies, Monoclonal↗