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Biomedical subjects

E Yuen

Publications and source records attributed to E Yuen.

34 records · Page 2Linked to original sources
PubMed1988

Identification and characterization of human hemopoietic mast cell colonies.

Persisting mast cell colonies from human bone marrow and cord blood cells grown in semisolid agar cultures for over 56 days have been positively identified and characterized using morphology and cytochemistry. Mast cells demonstrated the following features: Cytoplasmic granules frequently contained the specific and characteristic papyrus rolls (transmission electron microscopy); mature cells were positive to the mouse monoclonal antibody YB5.B8 specific for human mast cells (raised against acute myeloid leukemia cells) and RPA-M1 specific for human monocytes but negative to the human basophil monoclonal antibody Bsp-1; morphologically the cells were large (diameter 20-25 micron), deeply basophilic, and contained granules that measured up to 2 micron in diameter (May-Grünwald-Giemsa stain); the presence of heparin by the thrombin clotting time and positive staining with toluidine blue and alcian blue; the presence of histamine by a positive fluorescent o-phthalaldehyde stain; the presence of IgE receptor sites with human IgE and a rabbit anti-human IgE second antibody; and a unique zone of lysis around mast cell colonies occurred when cultured on peripheral blood feeder layers in agar plates that was not present around monocytic, neutrophilic, or eosinophilic colonies under the same culture conditions. Our results identify the cells in persisting colonies as mast cells and describe some specific characteristics that distinguish these cells from basophils.

Bone Marrow Cells↗
PubMed1987

Persisting colonies in agar cultures containing serum from patients with CML in blastic transformation.

Addition of serum from patients with chronic myeloid leukemia (CML) in both chronic phase and blastic transformation, to agar cultures of normal human marrow cells stimulated the growth of persisting colonies (day 35) containing either eosinophils or mast cells. Chronic phase serum stimulated an 800% increase in the total number of these colonies of which only 16% were mast cells. Serial studies using serum from 2 patients demonstrated that the proportion of mast cells increased during the progression to blastic transformation. The emergence of a greater proportion of persisting mast cell colonies and a decrease in absolute number of eosinophil colonies in agar cultures of normal marrow cells containing serum from patients with CML coincides with the emergence of blastic transformation and suggests that a significant change occurs in the absolute and relative concentration of hemopoietic growth factors in these patients.

Bone Marrow Cells↗
PubMed1986

Plasma lactoferrin in patients with neutropenia.

This study examines the role of plasma lactoferrin in the assessment of neutropenia. In particular, we have studied lactoferrin as an inhibitor of granulopoiesis and as an indicator of the size of the total blood granulocyte pool (TBGP). Plasma lactoferrin concentration was determined in a heterogeneous group of 30 patients with neutropenia. Serial plasma lactoferrin levels in a patient with cyclic neutropenia correlated with the cycles of the neutrophil count. Patients with splenomegaly had a grossly elevated lactoferrin:neutrophil ratio. Most chronic idiopathic neutropenia patients had no real clinical problems and a normal plasma lactoferrin level. The results provide further evidence to support the concept that plasma lactoferrin indicates the size of the TBGP and the lactoferrin: neutrophil ratio indicates the degree of granulocyte margination. There was no evidence to suggest that lactoferrin acting as a feedback inhibitor of granulopoiesis caused neutropenia in these patients.

Agranulocytosis↗
PubMed1986

Stimulation of persisting colonies in agar cultures by sera from patients with CML and AML.

Cord plasma contains colony-stimulating activity (CSA) which stimulates the in vitro clonal growth of neutrophils, eosinophils, macrophages, erythrocytes, and persisting mast cells in semisolid cultures. Analysis of day 35 colonies in agar cultures was found to be a suitable means of demonstrating this activity and discriminating between it and granulocyte-macrophage colony-stimulating factor (GM-CSF). Serum (10%) from patients with acute and chronic myeloid leukemia (AML and CML) was added to normal human bone marrow cultures to search for similar activity in these patient's serum. Although the number of colonies on day 12 (predominantly neutrophils and macrophages) was not significantly different from the number of colonies in cultures containing normal serum, the number of colonies increased 500% in cultures containing CML serum on day 35. Serum from patients with AML during regeneration also stimulated an increased number of colonies on day 35. Although both eosinophil and mast cell colonies were still present on day 35, only mast cell colonies persisted for 150 days. On day 35, cultures containing 10% CML serum contained predominantly eosinophil colonies (84%), whereas cultures containing AML serum contained predominantly mast cell colonies (76%). Although serum contains various CSFs, the specific factor which stimulates persisting mast cell colonies may be the human equivalent of murine persisting (P) cell-stimulating factor (Multi-CSF).

Agar↗
PubMed1986

Human bone marrow progenitor cells stimulated by cord blood.

Agar cultures of human bone marrow cells stimulated by cord plasma or irradiated cord blood feeder layers demonstrated the presence of a multilineage hemopoietic growth factor in cord blood. When bone marrow cultures stimulated with giant cell tumor-conditioned medium (GCT-CM) were supplemented with this cord blood-derived growth factor, total colony numbers increased by more than 50% after day 23 and persisted in culture for approximately 40 days. Marrow cultures stimulated by the cord blood-derived growth factor formed colonies of neutrophils, monocyte-macrophages, eosinophils, mast cells, and a few colonies containing a mixed cell population. The results suggest that, while GCT-CM contains granulocyte-monocyte colony-stimulating factor (GM-CSF), cord blood contains a high concentration of a multilineage hemopoietic growth factor, which may be multi-CSF.

Bone Marrow Cells↗
PubMed1984

An evaluation of serum erythropoietin estimation by a hemagglutination inhibition assay in the differential diagnosis of polycythemia.

A commercially available hemagglutination inhibition assay kit for the measurement of erythropoietin (EPO) was evaluated for its usefulness in the differential diagnosis of the polycythemic states. Serum samples were obtained from patients with polycythemia rubra vera (active and controlled), secondary and relative polycythemia and from normal controls. Firstly, we found that the mean EPO level (+/- SD) of our normal controls (81 +/- 69 miu/ml) was higher than the manufacturer's quoted normal range (15-59 miu/ml) and that there was a significant spread of values (7-233 miu/ml). Secondly, within each patient subgroup studied, the spread of data points was so wide that interpretation of individual data points would be impossible. We conclude that this assay kit is of little value for serum EPO estimation and in the differential diagnosis of polycythemia.

Diagnosis, Differential↗
PubMed1983

The use of peripheral blood feeder layers as a source of GM-CSF for human bone marrow cultures.

The use of peripheral blood feeder layers as a source of stimulus for colony formation by human granulocytic progenitor cells in semi-solid agar cell cultures was examined. Comparison with various conditioned media demonstrated that cultures stimulated by peripheral blood feeder layers produced the greatest number and largest colonies. The cell concentration in the feeder layers was more important than the total cell number. Feeder layer plates containing 2 X 10(5) cells at a concentration of 1 X 10(6) cells/ml proved to be just potent as the conventional feeder layer plates containing 1 x 10(6) cells/ml in 1 ml. Thus feeder layer plates can be more economical in terms of cell numbers than has previously been reported. By using a known panel of donors for the leukocytes, the number of sub-optimal batches of feeder layers was reduced. Addition of 1 microM adenosine 3':5'-cyclic-monophosphate or 10 micrograms/ml Li2CO3 to poor feeder layers enhanced their colony-stimulating ability.

Bone Marrow Cells↗
PubMed1983

An analysis of peripheral blood burst forming units-erythroid in the polycythaemic states.

Peripheral blood burst forming units-erythroid (BFU-E) were measured by the plasma clot cell culture technique in patients with the various subtypes of polycythaemia and compared to normal. 10 patients with active polycythaemia rubra vera (PRV) were found to have a mean BFU-E level of 48 +/- 15.8 (SEM) per 5 X 10(5) cultured cells which was significantly different from normals (4 +/- 1.1, P less than 0.02), patients with controlled PRV (7 +/- 1.6, P less than 0.025), secondary polycythaemia (1 +/- 0.3, P less than 0.015) and relative polycythaemia (0, P less than 0.015). Burst forming units were found to fall to normal levels in patients with PRV with appropriate disease control and then to rise again in patients untreated for more than 18 months. Clinical aspects. Measurement of BFU-E levels from the peripheral blood could provide a useful adjunct from an accessible source in the differential diagnosis of polycythaemia as well as being of use in serial monitoring of patients with PRV.

Bloodletting↗
PubMed1983

In vitro clonogenic assays in selective neutropenia.

Granulocyte-monocyte colony forming cell (GM-CFC) concentration and the proportion of GM-CFC in DNA synthesis (S) were determined in 43 patients with varying degrees of selective neutropenia, including 5 patients who were normal extremes (2.0-2.5 x 10(9) neutrophils/1), to study the diagnostic and prognostic significance of clonogenic assays and to determine the response of the committed myeloid stem cell to neutropenia. The proportion of GM-CFC in S proved to be a more useful parameter than the GM-CFC concentration. 75% of the patients with greater than 60% GM-CFC in S returned to normal within 1 month. Patients with less than 20% GM-CFC in S had at least a 10 times greater incidence of developing a malignant or autoimmune disease than the other 28 patients. The 11 patients with 41-51% in GM-CFC in S had greater than 1 x 10(9) neutrophils/1 and no significant clinical problems but all have remained mildly neutropenic for a long period. An indirect relationship existed between the degree of neutropenia and the proportion of GM-CFC in S (r = -0.70).

Adult↗
PubMed1979

Scanning electron and light microscope correlation of individual human bone marrow cells before and after culture in nutrient agar.

This study was undertaken with the aim of identifying the different cell types found in human bone marrow by examining their surface morphology. In an attempt to obtain a homogeneous cell population, cells were both fractionated by discontinuous albumin density gradient centrifugation (DADGC) and selectively grown in nutrient agar. Both cell preparations underwent the critical point drying technique before examination under both the scanning electron microscope (SEM) and subsequently the light microscope (LM). When the SEM image of individual cells was compared with the corresponding LM image, it was not easy to identify the different cell types, because of the shrinkage and distortion that occurred during their preparation. The shrinkage observed under the SEM amounted to a 45% reduction in mean cell diameter. This shrinkage was confirmed by comparing the SEM and LM images of the same cell. Although shrinkage occurred throughout the dehydration sequence, critical point drying was responsible for a 25% reduction in mean cell diameter. Furthermore, direct observation under LM of fixed cells drying in air from ethanol, revealed visible contraction of the cell and distortion of the cell membrane. We assume that a similar morphological change occurred during critical point drying. We conclude that the shrinkage and distortion, caused by the dehydration process involved in SEM preparation, severely limit the value of a study of surface morphology by SEM in the identification of the different cell types found in human bone marrow.

Agar↗
PubMed1979

Some properties of the colony forming cell in adult acute leukaemia.

Variations in the concentration and physical characteristics of the bone marrow derived colony forming cell(CFC) have been studied in patients with acute leukaemia. Two-hundred-and-fifteen marrow samples from 83 patients provide the basis for this analysis. CFC concentration confirmed the clinical remission/relapse status and yielded some guidelines to prognosis in individual patients while the proportions of CFC in DNA synthesis also proved to be a most reliable indicator of disease status. In remission, CFC concentrations return to normal values whilst on presentation and in the relapse phase of acute leukaemia CFC numbers are reduced. Biophysical profiles of CFC established using albumin density gradient and velocity sedimentation studies also indicated the state of the leukaemic process in individual patients. By applying physical laws to the data obtained from such profiles, the mean volume, diameter, density and mass of CFC were calculated. CFC from leukaemic patients in relapse were up to twice the volume and mass although slightly less dense than CFC from normal patients. The reasons for these changes are explained and discussed.

Acute Disease↗
PubMed1977

The effect of cyclic AMP on human colony forming cell and colony stimulating factor production.

The effect of cyclic AMP (cAMP) and related nucleotides on human colony forming cells (CFC) and those cells producing colony stimulating factor (CSF) was studied in vitro. When added at physiological concentrations (10(-2) to 1 micron), exogenous cAMP stimulated maximum colony formation in cultures without feeder layers. Related nucleotides stimulated colony formation to a lesser extent and in decreasing order of free energy. All nucleotides inhibited colony formation in concentrations above 1 micron. A velocity sedimentation cell separation technique was used to obtain cell fractions rich in CFC but poor in CSF-producing cells. Such fractions did not respond to cAMP stimulation. These studies suggest that exogenous cAMP stimulates human bone marrow to form colonies in vitro by increasing the release and/or production of endogenous CSF.

Adenine↗
PubMed1976

Effects of acidity, cations and alcoholic fractionation on absorption of heparin from gastrointestinal tract.

Heparin was introduced into the stomach or duodenum of mice separately in doses of ca. 250 mg/kg. A slight anticoagulant effect in the systemic circulation was detected in whole blood clotting times and factor X inhibition. In contrast to most drugs, more heparin was absorbed from the stomach than from the intestine. Suppressing ionization of heparin by simultaneous administration of acid resulted in improved absorption of heparin from the small intestine. Heparin was separated with ethanol into five molecular weight fraction: I, 17 999; II, 13 i99; III, 10800, IV, 8 700; and V, 6 700. Each was introduced into the duodenum of mice with citric acid. The maximum hypocoagulability was produced with fraction IV. When administered in distilled water instead of in citric acid, this heparin fraction did not produce an anticoagulant effect. These studies demonstrated that improvement of heparin absorption from the gastrointestinal tract can be obtained by the combination of suppressing ionization and selecting molecular size.

Animals↗
PubMedDate not supplied

Studies on human cord blood progenitor cells.

Analysis of agar cultures throughout a 56-day period determined the concentration and cell cycle status of at least 4 different subclasses of hemopoietic colony forming cells (CFC) in human cord blood (CB). Although the concentration of CFC in CB was not significantly different from bone marrow (BM) in day-12 cultures, neutrophil colonies reached their peak on about day 23 in CB cultures and on day 12 in BM cultures. This suggests that the CFC in CB are more primitive than those in BM. In CB cultures, colonies of small cells contained predominantly neutrophils on day 14 and eosinophils on day 35, while the late developing (day 35) colonies of large cells contained mast-cell-like cells (MCL).

Adult↗