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Biomedical subjects

K Lechner

Publications and source records attributed to K Lechner.

At least 91 records · Page 5Linked to original sources

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

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

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

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

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

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

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

Prognostic significance of surface marker expression on blasts of patients with de novo acute myeloblastic leukemia.

The prognostic significance of the expression of surface membrane antigens on the blasts of 123 consecutive patients with de novo acute myeloblastic leukemia (AML) was evaluated. For this purpose, reactivity of monoclonal antibodies (mAbs) CLB-ERY3 (antiblood-group H antigen), VIM-D5 (CD15), WT1 (CD7), MY7 (CD13), MY9 (CD33), VID-1 (antihuman leukocyte antigen locus DR [anti-HLA DR]), VIM-2 (CDw65L), VIM-13 (CD14), 63D3 (CD14) and anti-TdT with leukemic blast cell populations was prospectively analyzed with respect to the rates of complete remission (CR), continuous complete remission (CCR), and survival. The overall rate of CR was 65%, the 6-year rates of overall CCR and survival were 23% and 13%, respectively (median period of patient observation, 30 months). Of all Abs tested, four (CLB-ERY3, MY7, anti-TdT, and VIM-D5) were found to be of prognostic value. Reactivity of CLB-ERY3, MY7, and anti-TdT was predictive for CR (CLB-ERY3+, 43% v CLB-ERY3-, 73%, P less than .02; MY7+, 59% v MY7-, 91%, P less than .003; TdT+, 28% v TdT-, 71%, P less than .001, respectively) and probability of survival (significantly lower survival rates: CLB-ERY3+, P less than .02; MY7+, P less than .03; and TdT+ cases, P less than .001, respectively). Reactivity of VIM-D5 was significantly associated with a higher probability of CCR (P less than .01). Our results confirm earlier reports on the prognostic significance of expression of CD13 and TdT in AML and indicate CLB-ERY3 (antiblood-group H antibody) and VIM-D5 (CD15) as further markers predictive for the clinical outcome in patients with de novo AML.

Adolescent

Diagnosis of carriers of haemophilia A by RFLP analysis: Austrian results.

RFLP analysis with extragenic and intragenic probes was performed in 25 Austrian families with haemophilia A for the purpose of carrier diagnosis. Diagnosis could be established in 22 families, in 7 families with intragenic and extragenic probes, in 15 families with extragenic probes only. The remaining 3 families were not informative. During routine diagnosis we found three interesting cases which are described in the following paper. Firstly, we identified one deletion with Bcl I/p 114.12. Secondly, we observed an additional polymorphic band (5.2 kb) with Xba I/probe A. Thirdly, we saw one case where Bcl I/p 114.12 and Bgl I/1.8 were not in linkage disequilibrium.

Austria

Autoantibodies in chronic GVHD: high prevalence of antinucleolar antibodies.

Sera from 32 bone marrow allograft recipients were screened for the presence of autoantibodies 4-61 months post-graft. Sera from 12 of 19 patients with extensive chronic graft-versus-host disease (c-GVHD) stained the nucleolar region strongly in immunofluorescence, indicating the presence of specific antinucleolar antibodies. In contrast, none of three patients with limited and none of 10 patients without c-GVHD had antinucleolar antibodies. Antibodies reacting with nuclear constituents other than nucleoli were found in five of the 12 antinucleolar positive patients. The appearance of antinucleolar antibodies coincided with early clinical symptoms of c-GVHD. We conclude that the appearance of antinucleolar antibodies after bone marrow transplantation is specific for patients with extensive c-GVHD. Furthermore, the development of extensive c-GVHD is paralleled by the emergence of these antinucleolar antibodies.

Adolescent

Thromboxane A2 and prostacyclin generation in the microvasculature of patients with atherosclerosis--effect of low-dose aspirin.

Generation of thromboxane A2 (TxA2) and prostacyclin (PGI2) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the microvasculature made to determine skin bleeding time was investigated in 7 patients with atherosclerosis (angiographically verified obstructions of the femoral arteries) and in 7 normal control subjects apparently free of atherosclerotic lesions. Similar amounts of TxA2 (measured as thromboxane B2, TxB2) were generated at the site of plug formation in the patients with peripheral vascular disease (PVD) and in the control subjects. Significantly lower levels of PGI2 (measured as 6-keto-prostaglandin F1 alpha, 6-keto-PGF1 alpha) were found in blood from an injury of the microvasculature in the patients compared with the controls. These data do not suggest a major role of the platelet prostaglandin metabolism in the development of atherosclerosis. However, decreased synthesis of PGI2 by endothelial cells might contribute to the development and/or progression of atherosclerotic lesions. In the patients with PVD, low-dose aspirin (50 mg/day for 7 days) resulted in a greater than 90% inhibition of the TxB2 production at the site of plug formation. Following low-dose aspirin 6-keto-PGF1 alpha levels were below 20 pg/ml (limit of sensitivity of our radioimmunoassay procedure) in the majority of the samples. We therefore conclude that in patients with PVD a decreased synthesis of PGI2 by endothelial cells might contribute to the progression of atherosclerosis. Furthermore, low-dose aspirin treatment results in a similar inhibition of the platelet prostaglandin generation as recently observed in healthy subjects.

6-Ketoprostaglandin F1 alpha

High risk of acquired immune deficiency syndrome (AIDS) and of AIDS related complex (ARC) in hemophiliacs seropositive for more than 5 years.

A group of 90 hemophiliacs who had been regularly treated with non virus-inactivated factor VIII or IX concentrates were studied in 1983. At that time 50 patients were HIV-1-antibody positive, 6 additional seroconversions occurred until 1985. 26 of the 50 patients seropositive in 1983 are currently asymptomatic. 4 patients have developed the lymphadenopathy syndrome, 9 patients AIDS and 11 patients ARC (CDC IV C 2). 6/9 cases of AIDS and 10/11 cases of ARC have occurred only after 1985. Patients, who subsequently became symptomatic, had significantly higher IgG levels in 1983, otherwise no predictive laboratory tests were identified. Patients with T4 counts above 500/microliters became symptomatic later, but after 5 years the incidence of AIDS was comparable in patients with original T4 counts of more than or below 500/microliters.

AIDS-Related Complex

Interleukin-3 is a differentiation factor for human basophils.

The effect of recombinant human (rh) cytokines, interleukin-1 alpha (IL-1 alpha), interleukin-2 (IL-2), interleukin-3 (IL-3), interleukin-4 (IL-4), granulocyte/macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), monocyte/macrophage colony stimulating factor (M-CSF), interferon-alpha (IF-alpha), interferon-gamma (IF-gamma), and the tumor necrosis factor-alpha (TNF-alpha) on differentiation and function of metachromatic cells (MCS) was studied. Among all cytokines tested, rh interleukin-3 (rhIL-3) selectively induced a significant formation of MCS (IL-3: 1.1 +/- 0.6 x 10(5) v control: 0.02 +/- 0.15 x 10(5) MCS/mL suspension) and dose dependent increase in formation of intracellular histamine (IL-3, 100 U/mL: 95 +/- 23 ng/mL v control: 1.8 +/- 0.8 ng/mL) in a bone marrow suspension culture system (analyzed on day 14 of culture). Besides MCS, formation of eosinophils was observed in this culture system in the continuous presence of rhIL-3, whereas IL-3 pulse-stimulation for three hours and subsequent exposure to control medium induced growth of MCS but not of eosinophils. By combined immunofluorescence/toluidine blue staining, MCS were found to express a cell surface marker profile that corresponds to the immunological phenotype of peripheral blood basophils (MY-7(CD13)+, VIM12(CD11b)+, VIM2+, MAX1-, MAX24- and YB5B8-). Furthermore, cultured MCS expressed surface membrane receptors for IgE and could be triggered for nontoxic histamine release by a monoclonal anti-IgE antibody. To evaluate a possible influence of IL-3 on basophil function, studies were extended to freshly obtained blood basophils (healthy volunteers, n = 3). However, like all other cytokines tested, rhIL-3 failed to induce basophil histamine release. Taken together, our studies demonstrate that IL-3 is a differentiation factor for human basophils.

Antibodies, Monoclonal

Mast cell typing: demonstration of a distinct hematopoietic cell type and evidence for immunophenotypic relationship to mononuclear phagocytes.

The immunologic surface marker profile of human mast cells (MCs) was established using a combined toluidine/immunofluorescence staining procedure [49 monoclonal antibodies (MoAbs) tested]. Ascites (n = 9) MCs as well as enzymatically dispersed MCs from all organs tested (lung n = 11, skin n = 7, intestinum n = 10) exhibited an identical marker profile. MCs were recognized by MoAbs clustered as CD9 (anti-gp24), CD33 (anti-gp67), and CD45 (anti-gp220) as well as by MoAbs directed against membrane-bound IgE. MoAB YB5B8 (anti-gp145) selectively recognized MCs. Most significantly, however, MCs were stained by MoAbs MAX1 (anti-gp65), MAX3 (anti-gp68), MAX11 (anti-gp65), and MAX24 (anti-gp65). These antibodies bind to surface membrane antigens associated with a late stage of monocyte/macrophage differentiation. Thus, our results provide definite evidence that MCs share surface membrane markers with mononuclear phagocytes. In contrast, MCs are stained neither by lymphatic markers (CD1-8, 10, 19-24) nor by myelomonocytic markers (CD11-17). MCs also lack the interleukin-2 (IL-2) receptor (CD25), the T10 antigen (CD38), and most of the myelocytic markers expressed on peripheral blood (PB) basophils. Thus, MCs displayed a unique phenotype within the hematopoietic system. This new approach enabled us to enrich human lung MCs to a purity greater than 95% by means of negative selection with complement-mediated cell lysis. Purified MCs were subsequently stained with MoAbs and analyzed by flow cytometry, which confirmed the results obtained from the double-staining experiments. We next examined cultured metachromatic cells derived from bone marrow (BM) and peripheral blood colony-forming units (CFU). These metachromatic cells previously could not be classified by morphologic criteria alone and have therefore been termed basophil-like/MC-like cells. In this study, toluidine blue-positive cells obtained from either pooled multipotential colonies (day 14-CFU-GEM) or pooled myelocytic colonies (day 16/17-CFU-GM/G/M) were recognized by MoAbs MY7 (CD13), VIM12 (CD11b), and VIM2, as well as by an anti-IgE MoAb, after preincubation with IgE. In contrast, CFU-derived metachromatic cells were not stained by MoAb YB5B8. This marker profile corresponds to the immunologic phenotype of blood basophils and excluded a detectable formation of mature MCs in colonies derived from cultured hematopoietic stem cells.

Antigens, Surface

Anticardiolipin antibodies are elevated in HIV-1 infected haemophiliacs but do not predict for disease progression.

Levels of anticardiolipin antibodies (ACA) were measured in 55 patients with haemophilia A in serum samples obtained in 1983 and in 1987. Twenty-one patients were negative for anti HIV-1 antibodies in 1983 and remained negative in 1987; 34 patients had anti HIV-1 antibodies in 1983; 17 of these latter patients remained asymptomatic, whereas 17 patients developed ARC or AIDS during the 4 years follow-up. Thirteen anti HIV-1 negative patients had elevated ACA levels in 1983; subsequently, a significant decrease was observed in all these subjects (p less than 0.001). All anti HIV-1 positive patients had elevated ACA levels in 1983; normal values were found in 9 patients in 1987. Yet, these changes were not significant (p greater than 0.05). ACA levels were significantly higher in HIV-1 infected patients than in those without anti HIV-1 antibodies (p less than 0.05). There was no difference of ACA levels between the two anti HIV-1 positive patient groups, be it in 1983 or be it in 1987 (p greater than 0.05). There was no correlation of ACA levels with serum IgG concentrations, CD4+ lymphocytes, or the consumption of factor VIII concentrates.

Acquired Immunodeficiency Syndrome

Identification of the target platelet glycoprotein in autoimmune thrombocytopenia occurring after allogeneic bone marrow transplantation.

We report the case of a patient who developed autoimmune thrombocytopenia after allogeneic bone marrow transplantation from her HLA-identical sister. An IgG autoantibody was detected that bound to the platelet glycoprotein IIb/IIIa and to the HLA class I proteins. Immunoprecipitation studies with radiolabeled platelets revealed additional antibody binding sites on proteins of 214 kDa molecular weight under nonreduced conditions and 65 and 56 kDa molecular weight under reduced conditions.

Adult

Organization and nucleotide sequence of a transcriptional unit of Methanococcus vannielii comprising genes for protein synthesis elongation factors and ribosomal proteins.

By a chromosome walking strategy the DNA region from Methanococcus vannielii flanking the genes for protein synthesis elongation factor (EF) 1 alpha and EF-2 was cloned and sequenced. A gene organization of 5' - beta' - open reading frame (ORF) 1 - ORF2 - S12 - S7 - EF-2 - EF-1 alpha - S10 - ORF3 - ORF4 - 3' was found where beta', S12, S7, S10, EF-2, and EF-1 alpha represent gene products with sequences similar to the beta' subunit of RNA polymerase, ribosomal proteins S12, S7, and S10, and EF-G and EF-Tu from Escherichia coli, respectively. ORF1-4 represent gene products with no known eubacterial counterparts. Northern blot analysis of transcripts and nuclease S1 mapping showed that transcription initiates between beta' and ORF1 and terminates at the 3' side of the S10 gene and that the genes from ORF1 to S10 are cotranscribed. Apart from the presence of two additional ORFs, ORF1 and ORF2, and of the gene for S10, this organization is identical to that of the eubacterial "streptomycin operon." ORF1 displays sequence similarity to rat liver ribosomal protein L30 and may represent one of the "additional" ribosomal proteins of Methanococcus. The sequenced part of the beta' gene and the EF-2 and EF-1 alpha gene products from Methanococcus are more similar to their eukaryotic than to their eubacterial counterparts. It appears, therefore, that the genetic organization of the translational components resembles the situation in eubacteria, whereas their primary structures are more eukaryotic in nature.

Amino Acid Sequence