Biomedical subjects

T Olofsson

Publications and source records attributed to T Olofsson.

At least 55 records · Page 3Linked to original sources

PubMed1987

Modulation of the production of leukemia associated inhibitor (LAI) and its interaction with granulocyte-macrophage colony-forming cells.

Leukemia associated inhibitor, LAI, reversibly inhibits DNA synthesis in normal human granulocyte-macrophage colony-forming units (CFU-GM). LAI is produced by myeloid leukemia cells, a subpopulation of normal nonadherent low-density mononuclear cells in peripheral blood and bone marrow, as well as by the human promyelocytic cell line HL-60. Normal low-density marrow cell absorbed LAI at 37 degrees C from HL-60 cell-conditioned medium. When normal marrow cells were treated with trypsin or chymotrypsin they lost their capacity to absorb LAI and also became insensitive to the inhibitory effect of LAI. These observations were taken as circumstantial evidence for the existence of a trypsin-sensitive LAI receptor on normal marrow cells, including CFU-GM. Glucocorticoid steroids (hydrocortisone, prednisolone, and dexamethasone) inhibited LAI production by acute myeloid leukemia (AML) cells, normal LAI-producing cells, and HL-60 cells. The fact that prostaglandin E1 (PGE) totally inhibited LAI production by normal cells and that indomethacin abrogated the inhibitory effect of adherent cells on LAI production suggested a role for adherent monocytic cells and PGE in the regulation of LAI production.

Bone Marrow↗

PubMed1986

Defective recloning capacity of granulocyte-macrophage colony-forming cells in chronic myeloid leukaemia.

We investigated the recloning capacity of normal and chronic myeloid leukaemia granulocyte-macrophage colony-forming cells (CFU-GM) after 7 d culture in methylcellulose. Normal CFU-GM were recloned with the formation of 3.52 +/- 1.12 secondary CFU-GM per primary d-7 colony. A frequency distribution of the colony-forming cells within d-7 colonies showed a heterogeneous distribution with the majority of d-7 colonies containing 1 or zero CFU-GM and a few colonies containing more than 30 CFU-GM. Separation of marrow cells by velocity sedimentation demonstrated that the recloning capacity was primarily expressed by the smallest colony-forming cells. In contrast, marrow or blood cells from 18 patients with Ph1-chromosome-positive CML in the chronic phase produced colonies with defective recloning capacity. Only 1 patient had a recloning value within the normal range; the others had a mean value of 0.35 (range 0-1.28) secondary colonies per primary d-7 colony. The recloning defect was not related to WBC or treatment, since 5 newly diagnosed patients with CML also showed defective recloning before any treatment was given, which is compatible with the defect being an inherent property of CML.

Bone Marrow↗

PubMed1985

Production, characteristics and mode of action of hemopoietic growth inhibitors in myeloid leukemias.

The best characterized hemopoietic growth inhibitors in myeloid leukemias are leukemia associated inhibitor (LAI) and leukemia inhibitory activity (LIA). Both are normal cell products overproduced in leukemia. LIA is identical with acid isoferritins and LAI is not identical with LIA. They act in different ways to inhibit normal stem cell growth. The overproduction of these putative normal regulators may explain the suppression of normal hemopoiesis typical of myeloid leukemias. Modulation of the production and the action of LAI and LIA may have potential therapeutic value in leukemia.

Colony-Forming Units Assay↗

PubMed1985

Adenosine diphosphate ribosyl transferase in marrow cells of patients with acute myeloid leukemia is related to differentiation and drug sensitivity.

The levels of adenosine diphosphate ribosyl transferase (ADPRT) have been quantified in Ficoll-Isopaque isolated marrow cells from 36 patients with acute myeloid leukemia (AML). The in vitro growth pattern in agar at diagnosis was also determined, and in 16 patients the in vitro drug sensitivity of the clonogenic cells (CFU-GM) to cytosine arabinoside and daunorubicin was measured. The ADPRT activities of the various marrow cell preparations correlated to the morphological diagnoses, in vitro growth patterns, in vitro drug sensitivities to cytosine arabinoside, and to the prognoses of the AML patients. Hence, ADPRT may be a useful marker for the pathophysiology associated to AML.

Bone Marrow↗

PubMed1985

Density distribution of chronic myeloid leukaemia and normal colony-forming cells in diffusion chambers (CFU-D) and agar (CFU-GM).

The density distribution in Percoll gradients of clonogenic cells forming colonies in diffusion chambers (CFU-D) or in agar culture (CFU-GM) was studied in chronic myeloid leukaemia (CML). The density distribution of CFU-GM in CML was homogeneous with peaks within 1.058-1.061 g/ml, which is slightly lower than normal. CFU-D, on the other hand, showed heterogeneous distributions both in CML and in normal controls. Two separable populations of CFU-D were recognized, one with the same or lower density than CFU-GM that formed almost exclusively neutrophilic colonies in diffusion chambers, and a second population concentrating in the density range 1.068-1.075 g/ml which primarily formed macrophage colonies. The second population contained colony-forming cells derived from both Fc-receptor positive and Fc-receptor negative precursor cells, suggesting that at least some colonies in diffusion chambers arise from Fc-receptor positive granulopoietic cells of intermediate maturity and/or monocytes. The concentration of CFU-D in peripheral blood was increased 40- to 100-fold in 2 patients currently off treatment who had increased WBC counts.

Agar↗

PubMed1985

Mechanisms for adherence of eosinophils to an antibody-coated surface.

Eosinophils may act by degranulation after attachment to a surface. As the mechanisms of adherence are not understood, we have investigated the dependency on Fc(IgG) receptors and other mechanisms by studying the adherence of human eosinophils to albumin-Sepharose beads coated with either specific rabbit IgG antibody, F(ab')2 antibody fragments or serum under different conditions. Adherence to Sephadex beads and albumin-coated microtitration plates was also investigated. 50% of the eosinophils adhered spontaneously to all 3 different surfaces not coated with the antibody, whereas only 25% of neutrophils and less than 10% of mononuclear cells adhered. A small but significant increase in adherence to albumin-Sepharose or albumin-coated plastic occurred after addition of the IgG-antibody, but not after addition of F(ab')2 fragments, indicating that the Fc region was responsible for some increase in adherence. Incubation of eosinophils with IgG-Fc fragments prevented the additional antibody-mediated adherence. As Fc receptor-negative eosinophils adhered almost as well as Fc receptor-positive cells, it appears that the Fc receptors are of minor importance and instead, a nonspecific adherence mechanism, possibly unique for the eosinophil, seems to be the most important in eosinophil adherence to antibody-coated surfaces.

Animals↗

PubMed1985

Isolation of leukaemia-associated inhibitor (LAI)-producing cells from normal peripheral blood.

LAI, leukaemia-associated inhibitor, has previously been shown to be produced by a subpopulation of null cells in myeloid leukaemia, and has the capacity to suppress the proliferation of normal granulopoietic stem cells, CFU-GM, in vitro. In the present study, low density mononuclear cells from normal peripheral blood were separated into adherent/non-adherent, phagocytic/non-phagocytic, T-lymphocytes/non-T cells, and Fc-receptor positive and negative cells in search for LAI-producing cells in normal blood. Cell fractions enriched for NK-cells were isolated from Percoll gradients and NK-activity and LAI-production were assayed in the different fractions. Anti-Leu-2, anti-Leu-3, and anti-HLA-DR were used to deplete mononuclear cells of cells positive for these monoclonals using a panning technique. It is concluded from these studies that normal LAI-producing cells belong to a non-adherent, non-phagocytic, non-T, non-B, Fc-receptor positive population which does not express NK-activity, and which is Leu-2, Leu-3 and HLA-DR negative. The results imply that LAI may be a novel feedback regulator of the proliferative rate of granulopoietic stem cells and that LAI is produced by a small subpopulation of cells in both blood and bone marrow.

Antibodies, Monoclonal↗

PubMed1985

Effect of zinc and other cations on the release of the eosinophil cationic protein.

The eosinophil cationic protein, ECP, is a unique eosinophil granule constituent, which is released extracellularly after exposure of the eosinophils to a non-phagocytosable surface such as complement-coated Sephadex beads. The ECP is released to some extent even in the absence of Ca2+ and Mg2+, though both these cations augment the release reaction tested alone, and an optimal release is observed only in the presence of 2 mmol/l Ca2+ and 2 mmol/l Mg2+ in the medium. Zn2+ at concentrations from 0.25-4.0 mmol/l inhibited the release of ECP in a dose-dependent fashion, with or without Ca2+ and Mg2+ in the medium. Mn2+ had dual effects, stimulating the ECP release in the absence of Mg2+ and Ca2+, and inhibiting the release in the presence of these cations. Li1+ caused minor inhibition of ECP release, but only in the absence of Ca2+ and Mg2+. The inhibitory effect of Zn2+ was immediate and reversible after washing of the cells, suggesting that the inhibition is due to interaction with the plasma membrane functions.

Blood Proteins↗

PubMed1984

Characterization of the cells in myeloid leukemia that produce leukemia associated inhibitor (LAI) and demonstration of LAI-producing cells in normal bone marrow.

LAI (leukemia associated inhibitor) is a high mol. wt glycoprotein that reversibly reduces the proliferative rate of normal granulopoietic stem cells but not of clonogenic cells in leukemia. LAI was originally found to be produced and released by cells in acute and chronic leukemia and may play a role in the suppression of normal hematopoiesis in these diseases. We now report the physical and functional characteristics of LAI-producing cells in myeloid leukemia; they have a medium density with peaks in the range of 1.075-1.080 g/ml in continuous Percoll gradients, they are large cells with a sedimentation velocity of about 13-15 mm/h and they are non-phagocytic, non-adherent, non-T, non-B, Fc-receptor positive cells and about equally distributed among C'-receptor positive and negative cells. Normal bone marrow was shown to contain LAI-producing cells present in the non-phagocytic Fc-receptor positive compartment of cells within the density range 1.075-1.080 g/ml. Presented data suggest that LAI-producing cells comprise a subpopulation of cells that may be involved in the regulation of normal granulopoiesis as well as in the suppression of normal hematopoiesis in leukemia. These data also show that LAI-producing cells are different from the cells producing another inhibitor (LIA) recently identified as acidic isoferritins.

Bone Marrow↗

PubMed1984

Detection of lactoferrin and myeloperoxidase release from single neutrophils by a protein A plaque assay.

A haemolytic plaque assay was adopted to detect release of lactoferrin and myeloperoxidase (MPO) from single neutrophils. Target erythrocytes coated with protein A were bound as a monolayer by poly-L-lysine to the surface of a plastic dish. Secreted lactoferrin and MPO induced plaque formation dependent on the reaction with complement and specific antiserum producing lysis of the protein-A-coated sheep red blood cells. Lactoferrin was found to be released spontaneously from a fraction of neutrophils while MPO was released only after phagocytosis, reflecting different mechanisms for degranulation of MPO-containing azurophil and lactoferrin-containing specific granules.

Antibody-Producing Cells↗

PubMed1984

The relationship between growth in agar, karyotype and prognosis in acute leukaemia.

The growth pattern in agar culture and the karyotype of bone marrow cells were studied in 79 patients with untreated acute non-lymphocytic leukaemia (ANLL). Results were divided into the following groups: (A) colony and cluster formation; (B) growth of less than 600 small clusters per 10(5) cells; (C) growth of more than 600 small clusters; (D) no growth in agar. Cytogenetically, the patients were divided into 3 categories: NN, normal metaphases only; AN, both abnormal and normal metaphases and AA, abnormal metaphases only. An association was seen between growth pattern and karyotype: the majority of NN patients (33/37) belonged to group (A + B) while in group (C + D) 20/24 patients were AN or AA. 37 patients were prognostically evaluable. The growth pattern in agar but not the cytogenetic pattern had prognostic implications. 25 patients with acute lymphocytic leukaemia (ALL) were also studied at diagnosis. Different growth patterns in agar had no impact on prognosis. No relationship was detected between growth pattern and karyotype in ALL.

Acute Disease↗

PubMed1984

Proliferation and differentiation of normal and chronic myeloid leukaemia (CML) marrow cells in suspension cultures.

Immature myeloid cells highly enriched for colony-forming cells, myeloblasts and promyelocytes were isolated in Percoll gradients (lighter than 1.065 g/ml) from patients with chronic myeloid leukaemia (CML) or normal healthy volunteers. The proliferation and differentiation of these cells were followed in suspension cultures in McCoy's medium (15% FCS) with or without the addition of 15% human placenta conditioned medium (HP-CM) over a culture period of 12-16 d. Ion-exchange chromatography and gel chromatography indicated that the proliferation-stimulating activity in HP-CM was colony-stimulating activity (CSA). In unstimulated cultures (without HP-CM), normal cells produced very few neutrophils; macrophage production dominated. CML cells, on the other hand, gave rise to neutrophils even in the absence of stimulatory factor(s). The effect of HP-CM was dependent on the initial concentration: at a 'low' (1 X 10(5)/ml) concentration, the addition of HP-CM resulted in a great increase in neutrophils, but at a 'high' (5-8 X 10(5)/ml) initial cell concentration, HP-CM gave only minimal increase in neutrophil numbers in both normal and CML cultures. These observations suggest endogenous differences between normal and CML precursors in their requirements for or responses to growth stimulatory or inhibitory factors.

Bone Marrow Cells↗

PubMed1984

Mechanisms for eosinophil degranulation; release of the eosinophil cationic protein.

Mechanisms for degranulation in human eosinophils were evaluated. Release of eosinophil cationic protein (ECP), a unique eosinophil granule constituent, was measured upon exposure of purified eosinophils to a large surface consisting of Sephadex beads coated with serum, which leads to complement activation. Extracellular release of approximately 15% of the cellular ECP occurred both with eosinophils from patients with eosinophilia and normal people. Almost all eosinophils isolated from patients with eosinophilia and normal people adhered to serum-treated Sephadex. The data suggest that interaction through C3 receptors is a prerequisite for ECP release from eosinophils when exposed to serum-treated Sephadex. Both cytochalasin B, cytochalasin D and hydrocortisone reduced the release of ECP. Neither the cytochalasins nor hydrocortisone inhibited the adherence of eosinophils to the Sephadex beads. Thus the inhibitory effect of these agents on ECP release is a direct effect on the degranulation process. ECF-A, histamine and colchicine did not affect the release mechanism. No direct relationship was found between degranulation and oxidative burst inasmuch as some soluble mediators induced a high respiratory burst without a concomitant ECP release. Our data suggest that mechanisms for degranulation are not fully identical in eosinophils and neutrophils.

Antigen-Antibody Complex↗

PubMed1984

Myeloid differentiation in liquid cultures of cells from patients with chronic myeloid leukemia: effects of retinoic acid and indomethacin.

To study the effects of retinoic acid (RA) and indomethacin on myeloid differentiation, normal and chronic myeloid leukemic (CML) bone marrow cells lighter than 1.065 g/ml were incubated in liquid cultures and grown in agar. Retinoic acid (RA) (10(-8) M and 10(-6) M) increased the number of clusters (3-40 cells) formed in agar and also increased the neutrophil production in liquid cultures. Indomethacin (10(-6) M) did not change the cell growth in agar. In liquid culture, however, more macrophages and fewer neutrophils were produced in the presence of indomethacin. The results suggest that RA enhances neutrophil production by stimulating the proliferation and maturation of a cluster-forming cell within the myeloblast-promyelocyte compartment. The stimulatory effect of indomethacin on macrophage production is probably secondary to its inhibition of prostaglandin synthesis, which inhibits the proliferation of monocyte precursor cells. No major differences were noted between CML and normal cells in their responses to RA or indomethacin.

Cell Division↗

PubMed1984

Prediction of response to chemotherapy in acute leukemia by in vitro drug sensitivity testing on leukemic stem cells.

Twenty-two patients with acute myeloid leukemia were studied for in vitro drug sensitivity of the leukemic clonogenic cells in agar. The cells were preincubated for 1 hr with 1-beta-D-arabinofuranosylcytosine (ara-C; 0.15, 0.3, 0.6, 1.2, and 2.4 micrograms/ml) or daunorubicin (0.018, 0.037, 0.075, 0.15, and 0.30 micrograms/ml), washed, and plated in agar, and cluster/colonies were counted after 10 days of incubation. Survival curves were constructed and used for calculation of the surviving fraction of clonogenic cells. In 18 patients treated with thioguanine-daunorubicin-1-beta-D-arabinofuranosylcytosine-prednisone, the in vitro drug sensitivities could be correlated to the in vivo response to therapy. Patients who entered remission (12 of 18) were significantly more sensitive to ara-C (p less than 0.005) and to daunorubicin (p less than 0.02) than patients who did not enter remission (six of 18). All patients who entered remission, except two, had normal or increased sensitivity to both drugs, and all patients who did not enter remission, with one exception, had decreased sensitivity to one or both drugs. Comparison of the cytostatic effect of [3H]thymidine and ara-C suggested that, in some cases, ara-C killed more clonogenic cells than those in S phase, and in some cases, the cells seemed to be metabolically resistant to ara-C. We conclude that in vitro drug sensitivity tests on leukemic clonogenic cells reflect the patient's in vivo response to the tested drugs and may be used to study the biological properties of leukemic stem cells that determine their drug sensitivity.

Acute Disease↗

PubMed1982

Mechanism of benzene toxicity. Effects of benzene and benzene metabolites on bone marrow cellularity, number of granulopoietic stem cells and frequency of micronuclei in mice.

The effects of benzene and benzene metabolites *hydroquinone and catechol) on bone marrow cellularity, number of granulopoietic stem cells and on the frequency of micronuclei in polychromatic erythrocytes were investigated in mice. The dose-effect curve for benzene revealed that there was a threshold dose (approx. 100 mg benzene/kg body wt./day injected subcutaneously on 6 consecutive days) above which severe toxicity occurred in all three parameters. Also hydroquinone gave rise to adverse effects in the parameters studied, but the sequence of occurrence was different from that observed with benzene. These data are interpreted to indicate that hydroquinone is a hemotoxic metabolite of benzene in mice in vivo, but that other metabolites, or benzene itself, also probably contribute to the toxicity. Catechol gave no effects. However, due to acute effects like tremor and convulsions only rather low doses could be tested. Simultaneous administration of toluene dramatically reduced the toxicity of benzene, but gave only a small reduction of the hydroquinone-induced effects.

Animals↗

PubMed1982

Transfer of tissue cells to the fetus.

Several diseases of the fetus can be diagnosed prenatally. Some of them are due to insufficient production of a specific substance. It was therefore thought that, with the aid of fetoscopy, it might be possible to supply such an affected fetus with cells capable of producing the deficient substance. To ascertain whether tissue cells injected into the feto-placental circulation can pass through the microcapillaries of the placenta as early as in the second trimester, 125I-labelled cells of fetal liver were injected into an umbilical vessel ex utero after therapeutic abortion by hysterotomy. The distribution pattern of the radioactivity indicated that donor cells passed through the microcapillaries of the placenta and reached the target, i.e., the liver. In each experiment, the activity in the liver was higher than that in other organs studied. The activity in the brain and in the lungs was low. Transfer of tissue cells from a normal fetus to the circulation of an affected fetus in utero thus seems feasible. Permanent colonization of such cells would be facilitated by the fact that the donor as well as the recipient are fetuses of the second trimester and thus immunologically immature.

Blood↗

PubMed1982

Altered density, metabolism and surface receptors of eosinophils in eosinophilia.

A comparison was made between eosinophils from normal persons and patients with eosinophilia. Highly purified eosinophils were obtained by centrifugation in a Percoll density gradient. Studies were carried out on density distribution, oxygen consumption upon adherence to serum-coated Sephadex and expression of cell surface receptors for IgG and complement. In eosinophil leukaemia the density of eosinophils was abnormally low. Abnormal light density fractions of blood eosinophils were also detected in the hypereosinophilic syndrome (HES). Light density eosinophils of HES showed morphological signs of degranulation consonant with the finding of a low content of granular eosinophil cationic protein (ECP) suggesting degranulation in the circulation or abnormal granule formation in the marrow. In addition, such cells exhibited a higher oxygen consumption than eosinophils with normal density upon adherence to serum-coated Sephadex. Low density eosinophils showed a greater number of cells with Fc-IgG and complement receptors than high density cells. Likewise exudate eosinophils displayed an abnormally low density with higher than normal oxygen consumption indicating that eosinophils may be activated in the tissues. In one patient with HES, a febrile episode resulted in a disappearance of eosinophils with a normal density while abnormal low density eosinophils increased. Our findings suggest that eosinophils from some patients with eosinophilia may be 'activated' in the circulation.

Adult↗