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Biomedical subjects

N E Hansen

Publications and source records attributed to N E Hansen.

At least 37 records · Page 2Linked to original sources
PubMed1996

The bone-marrow infiltration pattern in B-cell chronic lymphocytic leukemia is not an important prognostic factor. Danish CLL Study Group.

In a multicentre study of 635 consecutive newly diagnosed patients with B-CLL, the histological bone marrow (BM) specimens were reviewed independently by each of 3 pathologists and found evaluable for BM infiltration pattern in 575 patients, 404 of whom had a CD5+, mainly FMC7-, faint surface-membrane immunoglobulin (SIg) fluorescence-intensity ppenotype. In these 404 patients the following BM infiltration patterns were found: mixed nodular-interstitial (30%), moderate interstitial (44%), heavy interstitial (20%) and diffuse packed (6%). In univariate survival analysis, significant differences were found according to BM pattern (p < 0.05), the presence of nodules being a favorable prognostic sign. In multivariate survival analysis in a model including age, clinical stage, BM pattern, BM lymphocytosis, WBC and sex, only age and stage but not BM pattern or BM lymphocytosis had independent prognostic significance. In stage A, progression-free survival was significantly longer in patients with nodular than in patients with non-nodular bone-marrow pattern. The overall survival of these patients, however, did not differ, possibly owing to the prompt and prolonged treatment given to most patients at the time of progression to stage B or C. We conclude that in CD5+, SIg(faint), mainly FMC7-B-CLL, bone-marrow histology may predict unstable disease in early clinical stage but is not important for treatment decisions, when these are based on clinical stage.

Age Factors↗
PubMed1996

Impaired migration in vitro of neutrophils from patients with paroxysmal nocturnal haemoglobinuria.

Migration of neutrophils in patients with paroxysmal nocturnal haemoglobinuria (PNH) was studied using two different complement-free in vitro model systems, subagarose and transendothelial migration. In the subagarose migration assay the mean migration distance of PNH neutrophils was slightly, but significantly, reduced to 1236 microns (range 753-1586, n = 6) compared to a normal mean of 1476 microns (range 1076-1768, n = 6, P = 0.016). By immunocytochemical staining for the urokinase type plasminogen activator receptor (uPAR) which is a glycosyl-phosphatidyl-inositol (GPI) anchored protein expressed by normal, but not by PNH-affected, neutrophils, it was shown that the uPAR-positive subpopulation of normal neutrophils predominated among the faster migrating cells (60-80% normal cells at the front of migration) while uPAR-negative (i.e. PNH-affected neutrophils) were more numerous close to the application well (5-30% normal cells). When migration of neutrophils was tested across a monolayer of human umbilical vein endothelial cells (HUVEC) cultured on polycarbonate filters, there was a 3-4-fold impairment of the migration of the PNH-affected neutrophils both in the absence of stimulation and after stimulation with fMLP (P < 0.001 in both cases). After IL-1 stimulation of the endothelium the impairment was even more pronounced (8-fold difference, P < 0.001). When the endothelial cells were grown on collagen-coated filters the impairment of the migration of PNH neutrophils was less pronounced, but still significant after stimulation with fMLP and IL-1 (2-fold, P < 0.05 in both cases). These results demonstrate that there is a complement-independent impairment of migration of neutrophils from patients with PNH which may be related to their failure to express GPI-linked proteins involved in cell migration and/or adhesion such as the uPA receptor and the CD66b antigen.

Cell Movement↗
PubMed1995

Unexpected hepatotoxicity after priming and treatment with molgramostim (rhGM-CSF) in acute myeloid leukemia during induction chemotherapy.

The effect of supplementing induction chemotherapy with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was studied in a randomized trial of 18 patients with acute myeloid leukemia (AML). Ten patients received rhGM-CSF, starting on day one to three before chemotherapy and continued for a maximum of 21 days after the start of induction treatment. Unexpected adverse effects of rhGM-CSF and chemotherapy combination included a transient decline in plasma coagulation factors II, VII, and X (5 of 5 patients) and an increased transcapillary escape rate of albumin (in 3 of 3 patients tested). The decline in coagulation factors was prevented in subsequent patients by prophylactic treatment with vitamin K. Although the small number of patients studied may not allow a definite conclusion, caution with regard to liver function should be shown in combining rhGM-CSF with intensive chemotherapy.

Adult↗
PubMed1995

The receptor for urokinase plasminogen activator is present in plasma from healthy donors and elevated in patients with paroxysmal nocturnal haemoglobinuria.

The urokinase plasminogen activator (uPA) is a proteolytic enzyme which converts the proenzyme plasminogen to the active serine protease plasmin. A cell surface receptor for uPA (uPAR) is attached to the cell membrane by a glycosyl-phosphatidylinositol anchor. Binding of uPA to uPAR leads to an enhanced plasmin formation and thereby an amplification of pericellular proteolysis. We have shown previously that uPAR is expressed on normal blood monocytes and granulocytes, but is deficient on affected blood monocytes and granulocytes in patients with paroxysmal nocturnal haemoglobinuria (PNH), and that uPAR is present in plasma from these patients. In this study a newly established sensitive enzyme-linked immunosorbent assay (ELISA) has been applied for quantitation of uPAR in plasma. Unexpectedly, we found that uPAR is not only present in PNH plasma but also in plasma from healthy individuals. In 39 healthy individuals the mean plasma-uPAR value +/- SD was 31 +/- 15 pM, median 28 (range 11-108), and the corresponding value for six PNH patients was 116 +/- 67 pM, median 90 (range 61-228). The elevated uPAR-level in PNH patients was highly significant (Mann-Whitney test; P < 0.0001), and may possibly contribute to the propensity for thrombosis in PNH by inhibition of the fibrinolytic system. Binding of pro-uPA by uPAR in plasma may interfere with the appropriate binding of pro-uPA to cell-bound uPAR and therefore inhibit cell-associated plasmin generation and fibrinolysis. It is likely that the uPAR in normal plasma reflects the overall level of activity of the uPAR-mediated cell surface proteolysis. The present ELISA may be used for studies of uPAR levels in plasma from patients with conditions in which this activity might be increased, such as cancer and inflammatory disorders. Future studies will determine if uPAR in plasma is a parameter of clinical importance in these diseases.

Chromatography, Affinity↗
PubMed1995

Stimulation tests for the bone marrow neutrophil pool in malignancies.

It has been known for decades that blood neutrophilia occurs after the administration of etiocholanolone, adrenocortical steroids, and endotoxins. Neutrophil leukocytosis in general may be due to several mechanisms such as increased stimulation of the myelopoiesis, increased release from the marrow, a shift from the marginated to the circulating pool (demargination), prolongation in the peripheral half-life, and decreased migration of neutrophils from the blood to the tissue. However, the principal cause of the neutrocytosis for each of the above mentioned agents is increased release of neutrophils from the bone marrow reserves. Since a sufficient reserve capacity is a prerequisite for optimal defenses against infections, the marrow response has been used to estimate the dose of chemotherapy expected to be tolerated without life-threatening neutropenia. However, none of the above "test substances" have gained widespread use due to adverse reactions or undesirable effects on neutrophil function. Recent progress in biotechnology has developed recombinant human (rh) hematopoietic growth factors ready for clinical use. Marrow myelopoiesis is stimulated by granulocyte colony-stimulating factor (rhG-CSF) and granulocyte-macrophage CSF (rhGM-CSF). The immediate effect, however, is mobilization of mature neutrophil granulocytes to the blood. Bone marrow cellularity seems to influence the neutrophil number mobilized during 24 hours by one subcutaneous injection of either rhG-CSF or rhGM-CSF. A recent pilot study has suggested such a "24 hour stimulation test" to predict severe neutropenia following cyclic chemotherapy. This concept is illustrated by two case reports. The "stimulation test" suggests that we may devise strategies to define patient subsets which may benefit from prophylactic growth factor administration during cyclic chemotherapy.

Bone Marrow↗
PubMed1995

Short-term rhG-CSF priming before chemotherapy does mobilize blood progenitors but does not prevent chemotherapy induced myelotoxicity: a randomized study of patients with non-Hodgkin's lymphomas.

The aim of this study was to evaluate the efficacy, safety and toxicity of short-term priming with recombinant human granulocyte colony-stimulating factor (rhG-CSF) immediately after diagnosis but before combination chemotherapy (CHOP) for non-Hodgkin's lymphomas. Of fourteen patients entering the study, seven received five days subcutaneous injection of rhG-CSF (5 micrograms/kg/day) before CHOP (CSF-group), and seven were treated with CHOP alone (control group). Blood samples were studied before and on days 1-5 during rhG-CSF priming as well as twice weekly after treatment. The number of blood and bone marrow progenitors was identified by clonogenic growth day 7, 14 and 21 of GM-CFU in semisolid medium. Blood absolute neutrophil counts increased in all rhG-CSF primed patients. The expansion of marrow myelopoiesis resulted in increased myeloid:erythroid ratios, increased bone marrow cellularity and increased numbers of myeloid progenitors both in the blood as well as the marrow. Chemotherapy induced neutropenia developed on day 9-12 in all patients independent of myeloid growth factor priming. However, neutropenia appeared earlier in the cytokine primed group (P = .0038). Five patients in the CSF-group and three patients in the control group were hospitalized with neutropenic fever, and septicemia was documented in three patients in the CSF-group. RhG-CSF induced expansion of myelopoiesis immediately before combination chemotherapy mobilized sufficient number of blood progenitors for apheresis but did not result in reduction of duration and degree of neutropenia in patients with newly diagnosed non-Hodgkin's lymphoma. Although the small number of patients prevents drawing definite conclusions, this time schedule for priming should be used with caution in the future due to an increased risk of hematologic toxicity.

Aged↗
PubMed1994

The receptor for urokinase-type plasminogen activator and urokinase is translocated from two distinct intracellular compartments to the plasma membrane on stimulation of human neutrophils.

The cellular receptor for urokinase-type plasminogen activator (uPAR) binds pro-urokinase (pro-uPA) and facilitates its conversion to enzymatically active urokinase (uPA). uPA in turn activates surface-bound plasminogen to plasmin, a process of presumed importance for a number of biologic processes including cell migration and resolution of thrombi. We have previously shown that uPAR is expressed on the plasma membrane of circulating neutrophils, and we now report that stimulation with phorbol myristate acetate (PMA), FMLP, or tumor necrosis factor-alpha results in a rapid increase in the expression of uPAR. This process is accompanied by an increased cell-associated plasminogen activation after preincubation of neutrophils with pro-uPA in vitro. By subcellular fractionation of unstimulated neutrophils, 50% of uPAR is recovered in fractions containing latent alkaline phosphatase, corresponding to an intracellular compartment of easily mobilizable secretory vesicles distinct from both primary and specific granules, whereas the remaining 50% of uPAR is associated with a compartment eluting close to the specific granules. In contrast, the ligand pro-uPA is primarily (approximately 80%) found in the specific granules, but small amounts of pro-uPA/uPA (approximately 20%) coelute with latent alkaline phosphatase. Stimulation of neutrophils with FMLP results in translocation of uPAR as well as of pro-uPA from the secretory vesicles, whereas stimulation with PMA is required to translocate material from specific granules. Flow cytometry of neutrophils saturated with exogenous diisopropyl fluorophosphate-uPA shows a large excess (approximately 90%) of unoccupied uPAR on resting as well as FMLP- and PMA-stimulated neutrophils, suggesting a possible role for exogenous pro-uPA in providing neutrophils with a potential for plasminogen activation. These processes may be important for neutrophil extravasation and migration through extracellular matrix and for the contribution of neutrophils to resolution of thrombi.

Biological Transport↗
PubMed1994

Histiocytic sarcomas and monoblastic leukemias. A clinical, histologic, and immunophenotypical study.

Eight histiocytic sarcomas, identified by examination of more than 2000 malignant lymphomas, are described. For comparison, tumor infiltrates from five monoblastic leukemias were also analyzed. The histiocytic sarcomas were all high-grade malignancies consisting of markedly pleomorphic large cells with many mitotic figures. At presentation, six of the patients had systemic symptoms (fever, fatigue, loss of weight), skin infiltrates, and lymphadenopathy. Despite aggressive chemotherapy, clinical remissions were short, and six patients died of disease .5-48 months (mean, 6.5 months) after diagnosis. The remaining two patients are alive and in partial or complete remission 7 and 12 months after diagnosis. Immunotypic examination showed that all the histiocytic sarcomas were positive for macrophage-related antigens and negative for antigens on B cells, T cells, myeloid cells, epithelial cells, and melanocytes. T-cell receptor and immunoglobulin genes were studied in three cases and were present in a germline configuration. One of the histiocytic sarcomas resembled Langerhans' cells in phenotype and morphology; it was classified as a Langerhans' cell sarcoma. The remaining histiocytic sarcomas did not express accessory cell-associated antigens, but more closely resembled "ordinary" tissue macrophages; they were positive for lysozyme and/or CD68, followed in frequency by CD11c, CD4, CD11b, CDw32, peanut agglutinin receptor, and CD13. Similar features were seen in the monoblastic leukemias. These conditions could only be distinguished from histiocytic sarcoma by clinical and morphologic, rather than immunophenotypic, criteria. Expression of oncoprotein p53 was studied in nine cases and was positive in six of six histiocytic sarcomas and one of three monoblastic leukemias. Rare malignancies show features consistent with the derivation from macrophages. Two entities may be distinguished: those that resemble antigen-presenting accessory cells and those that more closely resemble ordinary tissue macrophages. Recognition of these tumors is important clinically and requires assessment of clinical, morphologic, and immunophenotypic features, supplemented by analysis of T-cell receptor and immunoglobulin genes. Whether (or how) p53 gene mutations are implicated in their pathogenesis will be an important topic for future investigation.

Adolescent↗
PubMed1994

Expression of the receptor for urokinase-type plasminogen activator in normal and neoplastic blood cells and hematopoietic tissue.

Expression of the receptor for the urokinase type plasminogen activator (uPAR) has been studied by flow cytometry and immunohistology in normal blood and bone marrow cells, in vitro activated lymphoid cells, and tissue samples from reactive lymph nodes (n = 6), thymus (n = 2) and malignant lymphomas (n = 82), or leukemias (n = 32). HL-60 myeloid precursor cells and CD34-positive normal stem cells also were analyzed. In the normal cells, staining was confined to monocytes, macrophages, neutrophils, and myeloid precursors. No labelling was seen of normal or activated lymphoid cells. Purified CD34-positive hematopoietic progenitors were uPAR negative, but expressed uPAR during differentiation in short-term liquid culture stimulated in vitro by recombinant interleukin (IL)-1, IL-3, IL-6, granulocyte-macrophage colony stimulating factor (CSF), granulocyte-CSF, and stem cell factor. Enhanced uPAR expression was also seen in HL-60 cells after induction of differentiation with dimethyl sulfoxide or 1 alpha,25-dihydroxyvitamin D3. In lymphomas and leukemias, the staining pattern was similar to that seen in the normal cells with labelling of monocytic and myeloid that seen in the normal cells with labelling of monocytic and myeloid malignancies, but not of the neoplastic cells in B-cell or T-cell lymphomas or Hodgkin's disease. In conclusion, uPAR is a differentiation marker for myeloid and monocytic cells, and may act to facilitate migration of these cells in normal and pathologic conditions by cell-associated plasminogen activation. Whether expression of uPAR in myeloid and monocytic malignancies relates to their growth and behavior will be an important topic for investigations in the future.

Blood Cells↗
PubMed1994

Energy metabolism and nutrient oxidation in the pregnant mink (Mustela vison) as a model for other carnivores.

The mink is a strict carnivore and a seasonal breeder, which may be used as an experimental model for other carnivores. The present investigation comprised a total of 44 balance experiments, each including a 24-h measurement of heat production by indirect calorimetry, carried out from mating until close to parturition. For observations with a nonprotein respiratory quotient between 0.7 and 1.0 (n = 42), quantitative oxidation of nutrients was calculated. The weight gain of the uterus during pregnancy was studied in 41 females killed either before mating, before implantation, after implantation or in mid or late true gestation, and energy retention was calculated. Heat production did not increase with advancing stage of gestation. Mean energy retention was low and in some individuals with repeated measurements even negative, indicating that part of the energy requirement for pregnancy may be supplied by mobilization of body reserves. This was reflected by a high level (42%) of fat oxidation in relation to total heat production. Protein oxidation accounted for 38% of heat production. The weight gain of the uterus during pregnancy could be described by logarithmic functions. Energy deposition in fetal tissue was low and only averaged approximately 350 kJ 47 d after mating.

Animals↗
PubMed1994

Serum transferrin receptor levels in anaemic patients with rheumatoid arthritis.

The value of s-Transferrin Receptor (s-TfR) measurements in recognizing simultaneous iron deficiency in anaemia of chronic disease was examined in 35 anaemic patients with active rheumatoid arthritis. Based on a quantification of stainable bone marrow (marrow iron grade 0-4) and serum ferritin concentrations (levels < 60 micrograms l-1) compatible with iron deficiency) the anaemia was found to be aggravated by iron deficiency in 19/35 or 54% of the patients. There was no significant difference between the mean s-TfR concentrations in patients with adequate iron in comparison to patients with iron depletion [2.9 (1.6) mg l-1 v. 2.7 (1.4) mg l-1; t = 0.273; p = 0.786; Student's t-test]. Mean s-TfR levels in both patients with adequate iron and depleted iron stores were within the normal range, but tended to be higher than in normal individuals [mean (SD): 1.54 (0.43) mg l-1]. In patients with no stainable marrow iron (MIG 0; N = 15) a significant inverse correlation was found between s-TfR concentrations and s-ferritin levels (r = 0.57; p < 0.05). 5/15 patients with MIG = 0 exhibited significantly raised concentrations of s-TfR values > 3.05 mg l-1 (the highest normal value of the normal range). Increases of s-TfR levels were consistently moderate, and never exceeded a level of 7 mg l-1, which is markedly lower than concentrations measured in patients with iron deficiency anaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Priming with recombinant human hematopoietic cytokines before bone marrow harvest expands in vivo and enhances ex vivo recovery of myeloid progenitors in short-term liquid cultures.

BACKGROUND AND AIM: Short-term liquid marrow cultures (STLMC) are a potential source for autografting. We have previously shown that the quality of such grafts from transplantation candidates may be improved by hematopoietic cytokine support, especially if purified CD34-positive progenitors are cultured. The aim of this preclinical work was to quantitate ex vivo recovery of myeloid progenitors (colony-forming units-granulocyte/macrophage [CFU-GM]) in STLMC before and after short-term, in vivo treatment with recombinant human granulocyte colony-stimulating factor (rhG-CSF), granulocyte-macrophage colony-stimulating factor (rhGM-CSF), or interleukin-3 (rhIL-3). EXPERIMENTAL SETUP: Twenty-two sequential patients in marrow remission for hematological malignancies and eligible for autologous marrow transplantation received rhG-CSF or rhGM-CSF for 5 days or rhIL-3 for 10 days before marrow harvest. Marrow samples before and after in vivo priming were studied for CFU-GM in pre- and post-STLMC. RESULTS: After priming with rhG-CSF, rhGM-CSF, or rhIL-3, the number of isolated light-density cells increased nine-, six-, and two-fold, respectively. The total number of sampled (18 mL marrow) myeloid progenitors preculture (day 7/14 CFU-GM x 10(4) increased significantly from median 0.7/1.1 before to 37.3/26.7 after priming with rhG-CSF (n = 8) and from 5.6/3.4 before to 46.6/44.9 after priming with rhGM-CSF (n = 8) but remained unchanged (3.7/1.5 to 3.6/5.7) after priming with rhIL-3 (n = 6). The number of myeloid progenitors postculture (day 7/14 CFU-GM x 10(4) per 18 mL marrow) in cytokine-supported STLMC significantly increased from median 0.3/0.6 before to 7.0/5.3 after priming with rhG-CSF and from 1.9/1.6 before to 24.4/14.4 after priming with rhGM-CSF but remained unchanged (0.4/0.6 to 0.4/0.2) after priming with rhIL-3. Cytokine-primed and purified CD34+ marrow cells may be expanded in STLMC by a cytokine-driven differentiation into late myeloid progenitors and endstage cells. CONCLUSION: In vivo priming of bone marrow cells by hematopoietic cytokines significantly increases the recovery of harvested pre- and postculture myeloid progenitors. During cytokine-supported STLMC, early myeloid progenitors may differentiate into a "very late" progenitor pool with a potential for fast marrow regeneration. The number of such progenitors in cytokine-supported short-term liquid cultures may be sufficient for fast myeloid engraftment and complete peripheral blood or marrow stem-cell support after high-dose chemotherapy.

Antigens, CD↗
PubMed1993

Blood neutrophil increment after a single injection of rhG-CSF or rhGM-CSF correlates with marrow cellularity and may predict the grade of neutropenia after chemotherapy.

The grade of neutropenia after chemotherapy seems to be correlated to the bone marrow cellularity as judged by biopsies. Prolonged blood neutropenia after sequential chemotherapy reduces dose intensity and increases the risk of severe infections. A predictive non-invasive test for marrow cellularity is needed in the attempt to predict chemotherapy-induced blood neutropenia. Thirty-one patients with haematological disorders were studied with measurements of blood absolute neutrophil counts (ANC) 24 h after a single subcutaneous injection of recombinant human granulocyte colony stimulating factor (rhG-CSF) or granulocyte-macrophage CSF (rhGM-CSF). Before cytokine administration all patients had bone marrow biopsies performed. The median increase in blood ANC 24 h after cytokine administration was 15.9 x 10(9)/l (range 3.7-34.2) in 18 patients with normo- or hypercellular marrows and only 0.4 x 10(9)/l (range 0.0-11.2) in 13 patients with hypocellular marrows (P < 0.00001). An increase in ANC or more than 5 x 10(9)/l was predictive for normo- or hypercellular bone marrows with a sensitivity and specificity of 94% and 84%, respectively. A subsequent pilot study in selected patients with prolonged neutropenia was performed. The ANC increment in 12 cases before chemotherapy correlated to the grade of neutropenia and may predict the risk of febrile neutropenia. It is suggested that blood responsiveness to myeloid growth factors correlates with marrow cellularity and may identify outpatients with risk for severe neutropenia after cyclic chemotherapy.

Adolescent↗
PubMed1993

Different membrane expression of CD11b and CD14 on blood neutrophils following in vivo administration of myeloid growth factors.

During the administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) or granulocyte-macrophage CSF (rhGM-CSF) we studied the early and late changes of membrane antigen density on neutrophils. RhG-CSF and rhGM-CSF both caused an early transient reduction in blood neutrophilic granulocyte-concentration within the first 30 min after treatment followed by a marked later increase during the subsequent 24 h. During the early neutropenia quantitative flow cytometry showed an associated marked increase in the density of membrane CD11b from 169 x 10(3) before to 568 x 10(3) A.U. per cell induced by rhGM-CSF but a non-significant change by rhG-CSF, suggesting that different mechanisms may be responsible for the transient neutropenia. The subsequent neutrophil granulocytosis was followed by a significantly (P < 0.05) increased density of the CD14 antigen from 6.1 x 10(3) before to 15.9 x 10(3) A.U. per cell during treatment with rhG-CSF, but not by rhGM-CSF administration. These results demonstrate that the two cytokines may affect the function of neutrophilic granulocytes in different ways. The increased expression of CD11b could explain some of the side-effects during treatment with rhGM-CSF. The upregulation of CD14 induced by rhG-CSF may be clinically relevant, as CD14 is an opsonic receptor for lipopolysaccharide binding proteins, acting in the defence against Gram-negative bacterial infections.

Adult↗
PubMed1993

Short-term liquid marrow cultures are supported by a mixture of haematopoietic cytokines but do not purge for acute myeloid or lymphoid leukemic marrow cells.

Short-term liquid marrow culture (STLMC) is a potential source for autografting in leukemia. In a preclinical setting, including candidates for autologous marrow transplantation, we have studied STLMC supported by a selected mixture of clinical available recombinant human haematopoietic growth factors. STLMC of leukemic marrow cells were prospectively performed to evaluate the purging effect. Bone marrow cells cultured and supported by the selected mixture of rhIL-3/rhGM-CSF/rhEpo revealed an increased number of day 10-12 cultured cells, parallelled by an increased proliferation rate when compared to unstimulated cultures. The median number of myeloid progenitors recognized as day 7 and day 14 granulocyte-macrophage colony-forming units (day 7/14 GM-CFU) was significantly increased in the supported STLMC to 145/305 from 105/115 per ml culture (n = 7, p < 0.01). Further addition of rhKL did not enhance the numbers of day 7 or day 14 GM-CFUs per ml culture. In no instance was the number of clonogenic cells at the end of culture greater than the input day 0, except in cultures of purified CD34-positive marrow progenitors which resulted in an expansion of late myeloid progenitors. Cytokine-supported cultures of leukemic marrow cells from acute myeloid (n = 14) and lymphoblastic (n = 7) leukemia patients were established at the time of diagnosis. In the supported cultures, the cell number increased for myeloblast but was unchanged for lymphoblast leukemic marrow cells compared to non-supported cultures. Immunophenotypic and cytogenetic studies of selected leukemic cell samples identified unchanged myeloid or slightly reduced frequencies of lymphoblastic leukemic cells at the end of culture. This preclinical study supports the idea that the addition of a mixture of clinical available haemopoietic cytokines to STLMC increases the recovery of detectable myeloid progenitors which may enhance myeloid regeneration after autografting. No substantial selective loss of myeloid leukemic cells was found in the cytokine-supported short-term culture system.

Bone Marrow↗
PubMed1992

A soluble form of the glycolipid-anchored receptor for urokinase-type plasminogen activator is secreted from peripheral blood leukocytes from patients with paroxysmal nocturnal hemoglobinuria.

The cellular urokinase-type plasminogen-activator (uPA) receptor (uPAR) is a glycolipid-anchored membrane protein thought to be involved in pericellular proteolysis during cell migration and tumor invasion. In the present study, we have identified and characterized two soluble forms of uPAR which have retained their ligand-binding capability. One variant was generated in vitro by treatment of intact normal cells with either a phosphatidylinositol-specific phospholipase C (PLC) or endoproteinase Asp-N. The other soluble uPAR variant was secreted in vivo from peripheral blood leukocytes affected by the stem-cell disorder paroxysmal nocturnal hemoglobinuria (PNH), and was found in the plasma from these PNH patients as well as in the conditioned medium from cultured PNH leukocytes. Under normal conditions, we find no evidence for any shedding or secretion of a soluble uPA-binding counterpart to human uPAR in plasma. Unlike normal leukocytes, the PNH-affected cells do not express uPAR on the cell surface, although they do contain apparently normal levels of uPAR-specific mRNA. The secreted uPAR derived from PNH cells has a mobility in SDS/PAGE that is slightly higher than that of uPAR solubilized by PtdIns-specific PLC or detergent, but resembles that of a truncated, recombinant uPAR variant, which has its C-terminus close to the proposed glycolipid-attachment site, suggesting that the secreted protein has been proteolytically processed for glycolipid attachment. The presence in plasma from PNH patients of such a secreted, hydrophilic form of uPAR lends support to the hypothesis that the lesion underlying the PNH disorder resides either in glycolipid biosynthesis or in the function of an as-yet-unidentified transamidating enzyme assumed to cleave and assemble the truncated uPAR with the preformed glycolipid moiety.

Amino Acid Sequence↗