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K Lechner

Publications and source records attributed to K Lechner.

At least 271 records · Page 15Linked to original sources
PubMed1990

Human basophils express interleukin-4 receptors.

Interleukin-4 (IL-4), a multipotential lymphokine reputed to play an important role in the regulation of immune responses, interacts with a variety of hemopoietic target cells through specific cell surface membrane receptors. The present study was designed to investigate whether human basophils express IL-4 binding sites. For this purpose, basophils were enriched to homogeneity (93% and 98% purity, respectively) from the peripheral blood of two chronic granulocytic leukemia (CGL) donors using a cocktail of monoclonal antibodies (MoAbs) and complement. Purified basophils bound 125I-radiolabeled recombinant human (rh) IL-4 in a specific manner. Quantitative binding studies and Scatchard plot analysis revealed the presence of a single class of high affinity IL-4 binding sites (280 +/- 40 sites per cell in donor 1 and 640 +/- 45 sites per cell in donor 2) with an apparent dissociation constant, kd, of 7.12 x 10(-11) +/- 2.29 x 10(-11) and 9.55 +/- 3.5 x 10(-11) mol/L, respectively. KU812-F, a human basophil precursor cell line, was found to express a single class of 810 to 1,500 high affinity IL-4 binding sites with a kd of 2.63 to 5.54 x 10(-10) mol/L. No change in the numbers or binding constants of IL-4 receptors was found after exposure of KU812-F cells to rhIL-3 (a potent activator of basophils) for 60 minutes. No effect of rhIL-4 on 3H-thymidine uptake, release or synthesis of histamine, or expression of basophil differentiation antigens (Bsp-1, CD11b, CD25, CD40, CD54) on primary human CGL basophils or KU812-F cells was observed.

Antigens, Surface↗
PubMed1990

D-dimer and TAT measurement in patients with deep venous thrombosis: utility in diagnosis and judgement of anticoagulant treatment effectiveness.

The plasma levels of thrombin-antithrombin III-complexes (TAT) and the fibrin split product D-Dimer were measured in 39 patients with phlebographically proven acute DVT: 34 patients had proximal DVT, 5 had calf DVT. The sensitivity of D-Dimer and TAT measurements in the diagnosis of proximal DVT was found to be dependent on the duration of symptoms: 0 to 7 days (n = 27): elevated D-Dimer levels (greater than 120 ng/ml) = 1, D-Dimer Latex test positive (greater than 500 ng/ml) = 1, elevated TAT levels (greater than 6 ng/ml) = 0.88. Eight to 14 days (n = 7): elevated D-Dimer levels = 1, D-Dimer Latex test positive = 0.33, elevated TAT levels = 0.66; specificity: elevated D-Dimer: 0.48, D-Dimer Latex test: 1, elevated TAT: 0.76. Calf DVT patients (n = 5) had elevated D-Dimer levels, negative Latex tests and 3 of them had normal TAT values. Hemostatic and fibrinolytic parameters were also determined in 13 patients during heparin treatment of proximal DVT. Elevated D-Dimer and TAT levels rapidly decreased after initiation of anticoagulant therapy. In 2 of 13 patients a marked increase in D-Dimer and TAT levels was observed in periods of ineffective heparinization, documented by normal or only slightly prolonged thrombin clotting times. We conclude from our results that 1) D-Dimer EIA measurement, in contrast to TAT measurement, shows a very high sensitivity in the diagnosis of DVT, 2) due to low specificity this test can only be used to exclude thrombosis in patients with suspected DVT, and 3) the determination of the plasma levels of D-Dimer and TAT may be useful for judging the effect of anticoagulant treatment on thrombotic processes.

Adult↗
PubMed1990

IL-3 promotes basophilic differentiation of KU812 cells through high affinity binding sites.

The myeloid precursor cell line KU812 exhibits a constitutive potential to differentiate into basophilic cells. In the present study, the influence of recombinant human (rh)IL-2, rhIL-3, and recombinant human granulocyte-macrophage-CSF on basophilic differentiation of KU812-F cells was studied. Of all cytokines tested, rhIL-3 induced a significant increase in formation of metachromatically granulated cells (from 10% in control cultures up to 30% in cultures supplemented with 100 U/ml of rhIL-3) as well as dose-dependent (1.5- to 3 fold) increase in cellular histamine in KU812-F cell cultures. In addition, KU812-F cells exposed to rhIL-3 bound more IgE antibody than cells cultured in control medium with up to 3.3-fold increases in the mean fluorescence intensity on days 2 and/or 5 compared with control (p less than 0.001). RhIL-3 failed to induce significant changes in expression of the Tac-reactive subunit of the IL-2R (CD25), surface aminopeptidase N (CD13), ICAM-1 Ag (CD54), or CD40 Ag on KU812-F cells. To investigate the mechanism of IL-3 action on KU812-F cells, receptor analyses were performed by using 125I-radiolabeled rhIL-3. Quantitative binding studies and Scatchard plot analyses revealed the presence of a single class of 1910 to 2460 high affinity IL-3-binding sites per KU812-F cell with an apparent dissociation constant of 1.22 to 2.35 x 10(-9) M. Together, these results show that rhIL-3 promotes basophilic differentiation of KU812-F cells through a specific receptor.

Antigens, CD↗
PubMed1990

Pentostatin in refractory chronic lymphocytic leukemia: a phase II trial of the European Organization for Research and Treatment of Cancer.

Pentostatin was used to treat 26 patients with advanced B-cell chronic lymphocytic leukemia resistant to conventional treatment. Twenty patients had progressive disease on previous regimens and six had had partial remission and then relapsed 3-34 months after previous chemotherapy. Eleven patients had previously been treated with three different regimens. 10 had been treated with two regimens, and five had been treated with one regimen. Pentostatin was administered at a dosage of 4 mg/m2 weekly for 3 weeks, then 4 mg/m2 every other week for 6 weeks and once a month for 6 months. Seven of 26 assessable patients (27%) achieved partial remission and five (19%) achieved clinical improvement. The median duration of partial remission until relapse or death was 210 days. Myelosuppression was minor and transient in responsive patients, indicating some degree of selective effect on lymphocytes. Except for one patient who died of cerebral hemorrhage during the first 6 weeks of treatment, no drug-related deaths were registered. Major toxic effects included nausea in 17 patients (mainly grade 1), infections in 15, and liver enzyme elevations in five. Thus, pentostatin is active, even in patients with advanced B-cell chronic lymphocytic leukemia that is refractory to multiple chemotherapy regimens. Response can be achieved with mild myelosuppression.

Adult↗
PubMed1990

Azidothymidine (AZT) in the treatment of symptomatic HIV-1-infected hemophiliacs.

Twenty-one immunodeficiency virus 1 (HIV 1)-positive hemophilic patients were treated with Azidothymidine (AZT) for symptomatic HIV infection. The median observation period was 20.5 months. At 25 months the probability of survival was 82%, the probability of progression of disease from CDC III or IV C2 to IV C1 (AIDS) was 20% in patients on continuous AZT treatment and 50% in patients with interruption of treatment. Three patients developed severe leukopenia and 3 patients severe anemia during AZT treatment. In 1 patient a dose-dependent striking increase of transaminases during AZT treatment was observed. In 7 patients treatment was interrupted, in 1 patient because of anemia, in 1 because of pruritus and in 5 patients because of non-compliance. No significant changes in the consumption of clotting factor concentrates and number of bleeding episodes before and during AZT treatment were noted. We conclude, that both hematological and non-hematological side effects of AZT in HIV 1-infected hemophilic patients are comparable to those seen in other risk groups. AZT does not increase the bleeding tendency in this patient group.

Adolescent↗
PubMed1990

Molecular defect (Gla+14----Lys) and its functional consequences in a hereditary factor X deficiency (factor X "Vorarlberg").

Factor X (FX) "Vorarlberg" is a congenital FX deficiency characterized clinically by a mild bleeding tendency. Homozygous individuals have a FX activity of less than 10% in the extrinsic system and 25% in the intrinsic system. FX antigen is 20%. Using molecular techniques, two point mutations were detected in the coding sequence of the FX Vorarlberg gene: a G----A at base pair 160 in exon II resulting in a change of Gla14 (GAA) to Lys (AAA); a G----A at base pair 424 in exon V resulting in a change from Glu102 (GAG) to Lys (AAG). The mutations abolished a TaqI restriction site in exon II and an MnlI site in exon V. To determine whether these mutations are present on one or on both alleles, restriction analyses of amplified exon II and exon V fragments were performed. Analysis of the pedigree showed that the genotype for the mutation on exon II (homozygous versus heterozygous) correlates with the severity of the phenotypic coagulation defect. We therefore conclude that the mutation in exon II is responsible for the functional defect in FX Vorarlberg. We have also purified the mutant FX protein from patient plasma. Purified FX Vorarlberg is indistinguishable from normal FX on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its activity is 15% of normal FX upon activation with factor VIIa/tissue factor, 75% upon activation with factor IXa/factor VIIIa, and 100% upon activation with RVV. Activation at varying Ca2+ concentrations shows that the affinity of FX Vorarlberg for Ca2+ is decreased. Factor Xa Vorarlberg is able to convert prothrombin at a normal rate but also shows decreased affinity for Ca2+ in this interaction. Upon addition of Ca2+, FX Vorarlberg does not undergo the same conformational change as normal FX. Our data show that FX Vorarlberg has a decreased affinity for Ca2+ which impedes a normal conformational change. This leads to a decreased rate of activation by factor VIIa/tissue factor and by factor IXa. The decrease is much more marked for the extrinsic than for the intrinsic pathway.

Amino Acid Sequence↗
PubMed1990

Activation of coagulation and fibrinolysis in patients with arteriosclerosis: relation to localization of vessel disease and risk factors.

Activation markers of blood coagulation and fibrinolysis and several fibrinolytic parameters were determined in arteriosclerotic patients to investigate the relation between extension and main localization of vessel disease, risk factors and disturbances within the blood coagulation and the fibrinolytic system. Indications of an increased intravascular fibrin formation and subsequent fibrinolysis were found in peripheral artery disease (PAD) patients but not in coronary artery disease (CAD) patients. Compared with healthy controls PAD patients had elevated TAT (median: 3.2 ng/ml, 1.5-70 vs. 2.1, 1.2-4.7, p less than 0.005) and D-Dimer (median: 365 ng/ml, range 85-2000 vs. 185, 79-360; p less than 0.0001) plasma levels, whereas TAT (2.4, 1.2-13) and D-Dimer (190, 58-1000) levels of CAD patients were in the normal range. No associations were detected between risk factors of arteriosclerosis (hyperlipidemia, diabetes mellitus, cigarette smoking, hypertension) and the plasma levels of the activation markers TAT and D-Dimer. Independent from risk factors PAD and CAD patients had elevated plasma plasminogen activator inhibitor capacity (PAI cap). Our results provide evidence that 1) increased plasma levels of blood coagulation and fibrinolysis activation markers are not related to risk factors of arteriosclerosis but seem to be unspecifically caused by activation processes on arteriosclerotic vessel wall defects, 2) increased plasma PAI cap found in arteriosclerotic patients is a relatively unspecific phenomenon associated with arterial vessel disease.

Antithrombin III↗
PubMed1990

Low risk for hepatitis C in hemophiliacs given a high-purity, pasteurized factor VIII concentrate. International Study Group.

STUDY OBJECTIVE: To assess whether the hepatitis B virus (HBV), the hepatitis C virus (HCV), and the human immunodeficiency virus (HIV) are transmitted to hemophiliacs by a high-purity factor VIII concentrate in which the method of virus inactivation is pasteurization. DESIGN: Hepatitis B virus markers, the antibody to HCV (anti-HCV), the antibody to HIV (anti-HIV), and aminotransferases were measured on serum samples collected before the first concentrate infusion and at regular time intervals thereafter. SETTING: Seventeen hemophilia centers in Italy, the Federal Republic of Germany, Belgium, Austria, and the Democratic Republic of Germany. PATIENTS: Twenty-nine patients with hemophilia A who had not received a previous transfusion with blood products and who had normal alanine and aspartate aminotransferases (ALT and AST) were included in the final analysis. MEASUREMENTS AND MAIN RESULTS: No patient became positive for anti-HCV or anti-HIV or developed sustained increases in aminotransferase levels. Similarly, none of the 15 unvaccinated patients developed markers of HBV infection. CONCLUSION: This prospective study conducted in previously untransfused hemophiliacs highly susceptible to developing post-transfusion hepatitis shows that a large-pool clotting factor concentrate treated with pasteurization carries a low risk for transmitting HCV, the major causative agent of post-transfusion hepatitis.

Adolescent↗
PubMed1990

Diagnosis of protein C deficiency in patients on oral anticoagulant treatment: comparison of three different functional protein C assays.

The efficacy of three different protein C activity assays and of protein C antigen determination for the diagnosis of protein C deficiency was studied in 13 protein C deficient patients (11 with type I, 2 with type II deficiency) and in 51 presumably non-deficient patients (control group), both groups being on oral anticoagulant (OAC) treatment. For protein C activity measurement (1) the assay according to Francis (slightly modified) with thrombin activation and measurement of activated protein C in the aPTT system, (2) an assay using Protac activation and chromogenic substrate (Protac-CS) and (3) an assay using Protac activation and the aPTT system (Protac-PTT) were used. Protein C antigen was determined by Laurell immunoelectrophoresis. The three activity assays gave different results, with the highest values obtained by the Protac-CS assay and the lowest values by the Protac-PTT assay. The Francis assay gave intermediate results. Protein C activity and antigen values were significantly lower in protein C deficient patients compared to the control group. Protein C activity tests had a higher discriminative power than the antigen determination. After taking into account the intensity of treatment, by the Francis assay all deficient and non-deficient patients were correctly classified, by the Protac-CS and the Protac-PTT assay 2 and 4 patients, respectively, were misclassified and by the antigen assay 8 patients were misclassified. Calculation of the ratios of protein C activity to factor II activity was of high discriminative power. We conclude that for diagnosis of protein C deficiency protein C activity tests are superior to antigen determination not only in type II but also in type I deficient patients.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Hydroxycoumarins↗
PubMed1990

Recombinant human interleukin-3 expands the pool of circulating hematopoietic progenitor cells in primates--synergism with recombinant human granulocyte/macrophage colony-stimulating factor.

The in vivo effect of recombinant human interleukin-3 (rhIL-3) on peripheral blood (PB) levels of hematopoietic progenitor cells was studied in nonhuman primates. Subcutaneous administration of 33 micrograms/kg/d of rhIL-3 for 11 to 14 days to rhesus monkeys slightly raised leukocyte counts (twofold) and substantially expanded the pool of circulating stem cells in the second week of treatment. At the end of rhIL-3 administration, PB levels of granulocyte/macrophage colony-forming units (CFU-GM) increased by a mean of 12-fold; burst-forming units-erythroid (BFU-E) by ninefold; CFU-mix, by 12-fold; and CFU-megakaryocyte (Mk), by 13-fold as compared with their respective pretreatment values. Subsequent administration of recombinant human granulocyte/macrophage colony-stimulating factor (rhGM-CSF; 5.5 micrograms/kg/d for 5 days) to rhIL-3-pretreated animals further expanded the PB stem cell compartment leading to maximum levels of CFU-GM that were in average much more increased (63-fold) than CFU-GM levels under rhIL-3 (14-fold) or rhGM-CSF (12-fold) alone. This hitherto unknown effect of rhIL-3 on the pool of circulating progenitors, particularly in synergy with rhGM-CSF, may facilitate harvest of hematopoietic progenitor cells from PB for stem cell transplantation.

Animals↗
PubMed1990

Hemostatic and fibrinolytic parameters in patients with acute myeloid leukemia: activation of blood coagulation, fibrinolysis and unspecific proteolysis.

Blood coagulation, fibrinolytic and unspecific proteolytic parameters were investigated in 34 patients with acute myeloid leukemia. An increased activity of the coagulation system, documented by elevated thrombin-antithrombin III-complex (TAT) plasma levels, was found in 91% of the patients; 50% had increased elastase plasma levels. Hyperfibrinolysis, as shown by elevated fibrin split-product D-Dimer plasma levels, was detected in 91% of AML patients. Activation of these enzyme systems was not associated with relevant defects in blood coagulation or fibrinolysis in the majority of the patients investigated. In selected cases of promyelocytic M3 and monoblastic M5 leukemia, however, hypofibrinogenemia and alpha 2-plasmininhibitor deficiency was found, most likely due to depletion of these proteins in the course of disseminated intravascular coagulation and secondary hyperfibrinolysis. Significant correlations were calculated between TAT and fibrinogen (r = -0.57, P less than 0.005), TAT and D-Dimer (r = 0.89, P less than 0.0005), and D-Dimer and alpha 2-plasmininhibitor (r = -0.77, P less than 0.0005) levels. Indications of a pathogenetic importance of primary hyperfibrinolysis or unspecific proteolysis for hypofibrinogenemia and alpha 2-PI deficiency were not found.

Acute Disease↗
PubMed1990

Why clinicians should be interested in interleukin-3.

Interleukin-3 (IL-3), a product of activated immune cells has recently been cloned and introduced in preclinical and clinical trials. The biological target-cell spectrum of IL-3 is broad and includes progenitor cells of various hematopoietic lineages as well as multiple stages of stem cell differentiation. IL-3 also induces growth of most primitive hemopoietic progenitors (CFU-blast). Synergistic effects on growth of myeloid cells (i.e. macrophages, eosinophils and blood basophils) are obtained by sequential use of IL-3 and later-acting myelopoietic cytokines. In addition, IL-3 supports terminal maturation, prolongs survival and enhances the functional properties of myeloid cells through high-affinity binding sites. In vivo administration of IL-3 is followed by an increase in peripheral white blood cell counts as well as by an increase in the number of circulating progenitor cells giving rise to mature hemopoietic cells in response to more lineage-restricted growth factors. IL-3 also regulates growth of leukemic cells and primes them to become more sensitive to cell cycle specific cytotoxic drugs. IL-3 apparently represents a novel and unique hemopoietic growth factor. Its clinical use should offer new strategies in the treatment of cytopenia, leukemic disease and in stem cell transplantation.

Animals↗
PubMed1990

Effect of ritanserin, a 5-hydroxytryptamine2-receptor antagonist, on platelet function and thrombin generation at the site of plug formation in vivo.

To investigate the role of serotonin in platelet plug formation we studied, in eight healthy volunteers, the effect of ritanserin (a 5-hydroxytryptamine2-receptor antagonist) on the platelet release reaction (represented by beta-thromboglobulin release) platelet prostaglandin metabolism (represented by thromboxane B2 formation), and thrombin generation (represented by fibrinopeptide A formation) in the microvasculature. After administration of ritanserin lower amounts of thromboxane B1 were generated in the initial stages of plug formation, suggesting an inhibitory effect on the platelet prostaglandin metabolism. Similar amounts of beta-thromboglobulin were released after the administration of ritanserin compared with placebo, indicating a minor effect of ritanserin on the release reaction. Reduction of thrombin formation by ritanserin in the later stages of hemostasis suggested an inhibitory effect of this substance on the procoagulatory activity of platelets or endothelial cells. This could be attributable to interference with the formation or function of coagulation factor complexes on cell surfaces, or it could be the consequence of a reduction of the platelet activity.

Adult↗
PubMed1990

Recombinant human erythropoietin activates a broad spectrum of progenitor cells.

Twenty uremic patients on regular hemodialysis received recombinant human Erythropoietin (rhEPO) in a dosage of 50 U/kg body wt (N = 9) and 80 U/kg body wt (N = 11), respectively, three times weekly. The number of circulating hemopoietic progenitor cells colony-forming unit-granulocyte-erythrocyte-macrophage (CFU-mix), burst-forming unit-erythroid (BFU-E) and colony-forming-granulocyte-macrophage (CFU-GM) in peripheral blood were assayed weekly by means of a commonly applied in vitro clonal assay. A significant increase of peripheral CFU-mix, BFU-E and CFU-GM could be observed within one week of supplementation therapy in both groups. The increase of BFU-E was followed by a rise of hematocrit within four and three weeks, respectively. These results suggest that the stimulatory in vivo effect of rhEPO administered in therapeutical doses is not restricted to the erythroid lineage but also includes progenitor cells committed to the myeloid lineage (CFU-GM) as well as the multipotent progenitors CFU-mix. The increment of circulating progenitor cells was seen with a dosage of 80 U/kg body wt and 50 U/kg body wt as well.

Anemia↗
PubMed1990

Effect of conjugated estrogens on platelet function and prostacyclin generation in CRF.

In a double-blind, randomized, placebo-controlled cross-over study, we investigated in seven patients with chronic renal failure the effect of conjugated estrogens (0.6 mg/kg/day for 5 days) on template bleeding time and on thromboxane A2 (TxA2), beta-thromboglobulin (beta-TG) and prostacyclin (PGI2) concentrations in blood emerging from the template bleeding time incisions. Administration of conjugated estrogens resulted in a significant shortening of the bleeding time in six out of seven patients with a maximum effect 7 and/or 14 days following treatment. Both TxA2 (measured as thromboxane B2, TxB2) and beta-TG release in bleeding time blood were significantly higher following administration of conjugated estrogens as compared to placebo administration. No difference was seen in endothelial PGI2 (measured as 6-keto-prostaglandin F1 alpha) formation when patients were treated with conjugated estrogens as compared to placebo administration over the 28 day observation period. We conclude that in patients with chronic renal failure, infusion of conjugated estrogens results in a significant shortening of the bleeding time together with an increase in platelet reactivity, as indicated by an increase of TxA2 and beta-TG concentration in the microvasculature. No effect was seen on PGI2 production, thereby excluding a major effect on vascular prostaglandin metabolism.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

1-Deamino-8-D-arginine vasopressin in the treatment of non-haemophilic patients with acquired factor VIII inhibitor.

1-Deamino-8-D-arginine vasopressin (DDAVP) was administered to 3 patients with spontaneous factor VIII inhibitors. In 2 patients with baseline factor VIII levels above 1%, a marked increase of factor VIII activity after DDAVP infusion could be observed. No rise of factor VIII activity after DDAVP was seen in the 3rd patient with a baseline factor VIII level of less than 1%. Daily infusion of DDAVP resulted in a reduction of the efficacy, but the full effect could be retained when DDAVP was given at 48-hour intervals. The effect of DDAVP infusion on factor VIII levels in the 2 responding patients was superior to the treatment with 30 U/kg factor VIII concentrate and approximately equivalent to infusion of 45 U/kg factor VIII concentrate. DDAVP may be a useful and less expensive treatment for patients with acquired factor VIII inhibitors and a baseline factor VIII level of more than 1%.

Aged↗
PubMed1990

Gamma-interferon in myelodysplastic syndromes: a pilot study.

Eight patients with myelodysplastic syndrome (MDS; RA = 1, RAEB = 2, RAEB-t = 4, CMML = 1) received three cycles of recombinant gamma-IFN administered in 2-week intervals, each consisting of a 14-day period of subcutaneous injections at a daily dose of 0.1 mg/m2. Neither a complete nor a partial remission could be obtained. There was only one definite improvement consisting in a rise of hemoglobin level from 7 to more than 12 g/dl. Two minor improvements were due to a slight rise of platelet counts. Three patients developed acute leukemia under treatment with gamma-IFN. Our data suggest that gamma-IFN administered according to the treatment schedule as used in our trial has only a minimal beneficial effect in patients with MDS.

Adult↗