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Biomedical subjects

K Lechner

Publications and source records attributed to K Lechner.

At least 325 records · Page 18Linked to original sources
PubMed1987

In vitro culture studies of granulocyte/macrophage and erythroid progenitor cells in lymphoproliferative disorders.

Granulocyte/macrophage progenitor cells (CFU-GM) and erythroid progenitor cells (BFU-E) have been assayed in peripheral blood (PB) and/or bone marrow (BM) from 12 patients with acute lymphocytic leukemia (ALL), 16 patients with chronic lymphocytic leukemia (CLL) and 31 patients with various forms of non-Hodgkin lymphoma (NHL) without BM involvement. Progenitor cell growth in PB and BM from the NHL patients did not differ statistically from controls (p greater than 0.1). CFU-GM and BFU-E per ml PB were markedly increased in ALL and CLL patients (p less than 0.001) while CFU-GM and BFU-E per plated BM cells from these patients were severely depressed (p less than 0.001). Lymphoblasts from one ALL patient failed to inhibit CFU-GM and BFU-E-derived colony growth from control PB mononuclear cells. The high levels of circulating progenitor cells in ALL and CLL patients clearly distinguish them from other cytopenic hematological malignancies, in which decreased progenitor cell levels have been demonstrated previously (acute myeloid leukemia, hairy cell leukemia). The cause of this finding and its pathophysiological implication still remains to be established.

Bone Marrow↗
PubMed1987

Inhibition of prostacyclin and thromboxane A2 generation by low-dose aspirin at the site of plug formation in man in vivo.

In a double-blind placebo-controlled crossover study, we investigated in seven healthy male volunteers the effect of a low-dose aspirin regimen (35 mg acetylsalicylate per day for 7 days) on the formation of thromboxane A2 (TxA2) and prostacyclin (PGI2) in blood emerging from a standardized injury of the microvasculature made to determine skin bleeding time. When subjects were treated with placebo, there was rapid and substantial generation of TxA2 and PGI2 at the site of platelet-vessel wall interaction within the first 2 min after vascular injury. This was reflected by a greater than 100-fold and greater than 10-fold increase in thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in blood obtained from incisions made to determine bleeding time as compared with the corresponding plasma values. Low-dose aspirin caused a significant inhibition of both TxA2 and PGI2 generation in blood sampled from the skin incisions, represented by a 85% and 92% and 81% and 84% inhibition of TxB2 and 6-keto-PGF1 alpha, respectively, as compared with controls. We therefore conclude that rapid activation of both platelet prostaglandin metabolism and vascular PGI2 biosynthesis occurs at the site of platelet-vessel wall interaction, and low-dose aspirin results in a significant inhibition of both platelet and vascular cyclooxygenase activity. Thus, our data fail to confirm the concept of a differential effect of low-dose aspirin on platelet and vascular prostaglandin synthesis in man in vivo.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Human blood basophils display a unique phenotype including activation linked membrane structures.

To evaluate the membrane marker profile of human basophils a panel of well-established monoclonal antibodies (MoAbs, n = 60) was used for a combined toluidine/immunofluorescence staining procedure. Myeloid-associated MoAbs (particularly MoAbs against the LFA-1 family (CD11, CDw18), MoAbs directed against lactosylceramide (CDw17), anti-glycoprotein (gp) 150 MoAbs MCS 2 and MY 7 (CDw13), anti-gp 67 MoAb MY 9, anti Fc gamma-receptor (mol wt 40 kd) MoAb CIKM5, anti-CR 1 MoAb E 11, and the antiglycolipid MoAb VIM-2) were reactive with basophils, indicating a close relationship to other mature myeloid cells. Under normal conditions, basophils surprisingly express at least three activation-linked structures not detectable on mature neutrophils, ie, the p45 structure defined by MoAbs OKT-10 and VIP-2b, the p24 structure identified by the CD9 MoAb BA-2, and the receptor for interleukin 2 (IL 2) recognized by three different MoAbs (anti-TAC, IL2RI, anti-IL 2). Moreover, under short-term culture conditions basophils both in mononuclear cell (MNC) suspension and as purified fractions display the HLA-DR and T4 antigens. The neutrophilic/eosinophilic structure 3-fucosyl-N-acetyllactosamine is expressed on basophils only after neuraminidase treatment. Basophils were not stained at all by CD 16 MoAbs directed against the Fc gamma-receptor (mol wt 50 to 70 kd) of neutrophils, by the MoAb 63D3 (CDw12) recognizing the monocyte/granulocyte-associated p 200 antigen, and by the CDw 14 antibodies (VIM-13, Mo 2) defining the monocyte-specific structure p 55. Enriched basophils freshly obtained from chronic granulocytic leukemia (CGL) patients yielded identical results in FACS analyses. In summary, these data indicate that basophils generate a unique combination of surface determinants and possibly represent an activated cell population.

Antibodies, Monoclonal↗
PubMed1986

Posttransfusion purpura. A survey of 13 cases.

Thirteen cases of posttransfusion purpura (PTP) which were diagnosed in Germany and Austria from 1977-1985 are described. All patients were women with a mean age of 58.6 years (range, 36-77 years). All but one had been pregnant and received blood transfusions 2 to 12 days prior to the onset of PTP. The thrombocytopenic purpura was always severe with a nadir of platelet counts below 10 X 10(9)/l and lasted between 3 and 60 days. All patients recovered from PTP. Optimal therapy consisted of administration of high-dose IgG. Twelve of the 13 patients had developed platelet-specific Zwa antibodies (eight of them together with HLA antibodies), in one Zwa positive individual only HLA antibodies were detectable. Five of six HLA-DR typed patients carried DR3 which is considered an immunogenetic risk factor in PTP. Clinical awareness of this rare, but serious iatrogenic transfusion complication is prerequisite for prompt diagnosis and improved therapy.

Adult↗
PubMed1986

Indium 111-labeled platelet kinetic studies and platelet-associated IgG in hairy cell leukemia.

In order to study the pathogenesis of thrombocytopenia in patients with hairy cell leukemia (HCL), levels of platelet-associated IgG (PAIgG), platelet life span (MLS), and the sequestration site of autologous 111In-labeled platelets were measured in nine patients with HCL. Splenectomized patients (n = 4) had a higher platelet count (x = 122.5 X 10(9)/l; range, 80-190 X 10(9)/l) as well as higher levels of PAIgG (x = 10.7%; range, 5.8-16.9%), than nonsplenectomized patients (platelets x = 76 X 10(9)/l, range 40-100 X 10(9)/l; PAIgG x = 3.2%, range 2.2-4.2%). A normal recovery of 111In-labeled platelets was found in splenectomized patients, whereas a very low recovery was observed in the nonsplenectomized group (x = 70.2%, range, 50-82.5%, versus x = 22.4%, range, 15-28.2%). The MLS was borderline normal in all patients. The site of sequestration was the spleen in nonsplenectomized patients. The low recovery of 111In-labeled platelets in nonsplenectomized patients suggests "hypersplenism" with pooling as a major cause of thrombocytopenia, in addition to impaired thrombocytopoiesis and possible immune-mediated platelet destruction.

Adult↗
PubMed1986

Cytogenetic studies in bone marrow transplant recipients.

Chromosome studies were performed in 24 patients who underwent allogeneic bone marrow transplantation (BMT) for severe aplastic anaemia (8), chronic myeloid leukemia (5 in chronic, 2 in accelerated phase and 1 in lymphoid blast crisis), acute myeloid leukemia (6), acute lymphoblastic leukemia in relapse (1) and Hodgkin's disease (1). Donor-cell type engraftment was demonstrated in 21 patients: in all 17 sex-mismatched transplants and - as demonstrated by reconstitution with Ph-negative cell populations - in 4 CML patients with a sex-matched donor. Recipient-type mitoses were seen in the bone marrow of 5 cases (1 SAA, 3 CML, 1 AML) after transplantation. They were only observed on one occasion in patients with SAA (4 of 25 on day 33) and AML (44 of 50 on day 14). Despite the continued demonstration of some Ph-positive mitoses in 3 patients with CML up to day 28, 323 and 451 after BMT, respectively, all surviving CML patients are still in complete haematological and clinical remission. So far the significance of these cytogenetically abnormal persisting host cells remains unknown.

Adolescent↗
PubMed1986

Coumarin induced acral skin necrosis associated with hereditary protein C deficiency.

Hemorrhagic skin necrosis of the toes was observed in a patient with heterozygous protein C deficiency (protein C:Ag 32% and protein C activity 30%) on the 4th day of coumarin treatment overlapping with effective intravenous anticoagulation with heparin. Family studies revealed protein C deficiency in two sisters of the proposita without a history of thromboembolic disease. Immunologic studies in the proposita at the time of coumarin necrosis revealed slight depression of complement factor C4 and the presence of immune complexes. The present case and review of the literature show that the pathogenetic mechanism leading to coumarin necrosis in patients with protein C deficiency seems not yet to be fully understood.

Adult↗
PubMed1986

Myeloid progenitor cells in the peripheral blood of patients with hairy cell leukemia and other "leukemic" lymphoproliferative disorders.

We assayed granulocyte-macrophage committed progenitor cells (CFU-GM), erythroid committed progenitor cells (BFU-E) and pluripotent hemopoietic progenitor cells (CFU-MIX) in the peripheral blood of patients with hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL). In 8 HCL patients retaining their spleens, the number of circulating CFU-GM, BFU-E and CFU-MIX were under the lower limits of normal controls in 6, 6 and 5 cases, respectively, and were in the lower normal ranges in the remaining cases. Six splenectomized HCL patients had generally more circulating progenitor cells than their nonsplenectomized counterparts. In the peripheral blood of 2 patients with ALL and 3 patients with CLL, progenitor cells of all types were markedly increased compared to their respective values in the blood of control subjects. Hairy cells from 2 HCL patients failed to inhibit CFU-GM, BFU-E and CFU-MIX derived colony growth from control peripheral blood mononuclear cells. In 3 HCL patients previously low circulating progenitor cells did not rise 5-7 months after RC-alpha 2-IFN treatment despite normalization of peripheral blood counts. Our results suggest that a reduction of the committed and pluripotent progenitor cell compartment might be at least in part responsible for the pancytopenia in the majority of patients with HCL.

Adult↗
PubMed1986

Thromboembolism in patients with prosthetic heart valves. An adequately controlled intense anticoagulant therapy and its influence on the occurrence of thromboembolism in relation to valve type.

This study was designed to evaluate the efficacy of carefully controlled treatment with oral anticoagulants in patients with different mechanical heart valve prostheses. One hundred eighty-one patients with various types of prosthetic valves (mitral 89, aortic 87, combined 5) received oral anticoagulation aiming at Thrombotest (TT) values between 5% and 12%. Median follow-up was 46 months; 80.8% of all TT determinations were below 12%. The thromboembolic rate was 0.25%/year in patients with aortic valve replacement (AVR) and 4.87%/year in patients with mitral valve replacement (MVR). There was a strikingly lower incidence of thromboembolism with newer types of valves (Björk-Shiley convex-concave) in the mitral position under exactly the same intensity and stability of anticoagulant treatment. Clinically overt valve occlusion could be almost completely prevented (0.12%/year) in prostheses at both sites. Severe hemorrhage occurred at a rate of 1.71%/year and fatal bleeding at a rate of 0.37%/year. Our results indicate that carefully controlled anticoagulation is effective in the reduction of thromboembolic complications at a reasonable risk of bleeding.

4-Hydroxycoumarins↗
PubMed1986

Platelet-associated immunoglobulins IgG, IgM, IgA and complement C3c in chronic idiopathic autoimmune thrombocytopenia: relation to the sequestration pattern of 111indium labelled platelets.

Levels of platelet-associated immunoglobulins (PAIg) IgG, IgM, IgA and complement C3c were related to parameters of 111Indium-labelled platelet kinetics in 17 patients with chronic idiopathic autoimmune thrombocytopenia (cAITP). Elevated levels of PAIg/C3c were found in 14 patients (82%) (PAIgG n = 13, PAIgM n = 11, PAIgA n = 1, PAC3c n = 5). Only PAIgG correlated with platelet counts (RS = -0.71, p less than 0.01). Mean platelet life span (MLS) was shortened in all patients (median 12.0 h, range 0.3-45.6 h) and correlated with the platelet counts (RS = 0.49, p less than 0.05). MLS was correlated with PAIgG (RS = -0.52, p less than 0.05), but not with PAIgM, PAIgA, or PAC3c. The site of sequestration was splenic in 10 patients and splenic-hepatic in 7 patients. Although no significant correlation between either site of platelet sequestration and any of the investigated PAIg/C3c was demonstrable, platelets coated with higher PAIgG levels were more readily sequestrated in the spleen, while elevations of PAC3c were found in 4 out of 7 patients with hepatic involvement.

Adolescent↗
PubMed1986

Circulating committed and pluripotent haemopoietic progenitor cells, in infants.

Circulating CFU-GM, BFU-E and CFU-MIX were assayed in 21 infants aged between 1 day and 44 weeks. Compared to 15 adults, progenitor cells of all types were increased until 10 weeks following birth and approached the respective ranges of adults thereafter. The mean increases of progenitor cells in infants aged between 1 day and 10 weeks were 26-fold for CFU-GM, 7-fold for BFU-E and 5-fold for CFU-MIX. Our results demonstrate that not only committed progenitor cells (CFU-GM, BFU-E), but also early progenitor cells with the capacity for self-renewal (CFU-MIX), are increased in early infancy. These data further support the hypothesis that high levels of blood progenitor cells in very early stages of life reflect the colonization process of developing bone marrow by circulating progenitor cells and demonstrate the terminal phase of this process during the first 10 weeks after birth.

Adult↗
PubMed1986

Increased risk of thrombosis due to abnormalities of the hemostatic system.

In recent years a number or hereditary or acquired abnormalities of the hemostatic system have been discovered which predispose to thrombosis. The type of this abnormality determines not only whether there is a tendency to venous or arterial thrombosis but also predisposes in some instances to thrombosis at a specific site. Such hemostatic abnormalities may be present in 10-30% of patients with a history of venous thrombosis. The detection of a thrombophilic state has important implications as regards the choice and the duration of antithrombotic treatment.

Blood Coagulation Disorders↗