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Biomedical subjects

M H Freedman

Publications and source records attributed to M H Freedman.

At least 127 records · Page 7Linked to original sources
PubMed1986

Clinical utility of marrow cell tissue cultures in acute leukemia of childhood.

To determine the clinical value of tissue culture techniques in the study of acute leukemia, marrows from 50 children (40 acute lymphoblastic [ALL], 10 acute myeloblastic [AML]) were cultured by the use of an AML blast colony assay and the CFU-GEMM assay. In the AML assay, AML marrow gave rise to high numbers of blast colonies within 24 to 48 hr; in sharp contrast, 37 of 40 ALL marrows did not yield colonies in this assay. In the CFU-GEMM assay, AML marrow produced excessive numbers of monocyte-macrophage CFU-C colonies, an obvious background of individual macrophages and clusters, and occasional blast colonies. ALL marrow yielded very low numbers of granulocytic CFU-C colonies, no background of macrophage cells, and no blast colonies. These clear-cut differences in cellular growth kinetics in vitro between ALL and AML marrows should allow confirmation of the type of acute leukemia within 24 to 48 hr. The colony assays may also be valuable in differentiating ALL from AML in difficult diagnoses when conventional approaches are nondiagnostic.

Acute Disease↗
PubMed1986

Selective protection of tubercidin toxicity by nitrobenzyl thioinosine in normal tissues but not in human neuroblastoma cells.

Tubercidin, an adenosine analogue, is toxic to human neuroblastoma cell lines, to peripheral blood mononuclear cells (PBMCs), and to myeloid colony-forming cells (CFU-C) as tested by a short-term labeled precursor uptake and by a clonogenic assay. When it was co-administered with a potent purine transport inhibitor, nitrobenzyl thioinosine (NBTI), the cytotoxic effect of tubercidin was abolished in PBMCs but not in neuroblastoma cells. Studies of nucleoside transport in neuroblastoma cells demonstrate that although [3H]NBTI binds to the plasma membrane of these cells, the transport of thymidine into the cells is only partially inhibited in the presence of excess NBTI. These data imply that neuroblastoma cells contain a nucleoside transport mechanism which is insensitive to NBTI. "Host protection" with a nucleoside transport inhibitor such as NBTI, may allow effective therapy with otherwise toxic dosages of tubercidin and other cytotoxic nucleosides in patients with neuroblastoma.

Biological Transport↗
PubMed1986

Clinical and in vitro antiproliferative properties of recombinant DNA-derived human interferon-alpha 2.

The properties of the recombinant DNA-derived human leukocyte interferon, HuIFN alpha 2, were studied in patients with advanced leukemia or lymphoma. In vitro, HuIFN alpha 2 induced an increased activity of 2-5A synthetase in leukemic and in control cells indicating cellular responsiveness to IFN. HuIFN alpha 2 also produced a dose-responsive decline in marrow leukemia blast progenitor colony growth, and in normal hematopoietic colony formation in vitro, confirming its antiproliferative effect. A course of intravenous therapy given to a lymphoma patient produced a modest decline in peripheral white blood cell (WBC) and neutrophil counts; higher, more frequent doses in a second patient induced a profound drop in WBC's, neutrophils, and platelets. When the leukemia patients were given an intravenous course of HuIFN alpha 2 as a sole agent, blast cytoreduction was seen in peripheral blood in three patients, and in marrow of one patient with acute myeloblastic leukemia (AML). Elevated 2-5A synthetase levels could be detected after therapy. No modulation of leukemic cell markers was seen after in vitro or in vivo treatment with HuIFN alpha 2, implying that the cytoreduction was not linked to blast cell differentiation. These studies suggest that this subtype of recombinant DNA-derived IFN has antileukemic properties, and indicates the possibilities for IFN as an adjunctive form of therapy in leukemia.

2',5'-Oligoadenylate Synthetase↗
PubMed1986

Regulation of interferon receptor expression in human blood lymphocytes in vitro and during interferon therapy.

Interferons (IFN) elicit antiviral and antineoplastic activities by binding to specific receptors on the cell surface. The binding characteristics of IFN to human lymphocytes were studied using IFN alpha 2 labeled with 125I to high specific activity. The specific binding curves generated were analyzed by the LIGAND program of Munson and Rodbard to determine receptor numbers. The number of receptors in peripheral blood lymphocytes (PBL) and tonsillar B-lymphocytes (TBL) from normal individuals were 505 +/- 293 (n = 10) and 393 +/- 147 (n = 3) respectively. When these cells were preincubated in vitro with unlabeled IFN alpha 2, the receptor number decreased to 82 +/- 45 and 61 +/- 16 respectively. Receptor binding activities recovered gradually over a period of 72 h when the cells were incubated in IFN-free medium. This recovery of receptors could be blocked by the addition of actinomycin D to the incubation medium. A similar decrease in receptor expression was observed in vivo in PBL from patients being treated daily with 5 X 10(6) units/m2 per d of IFN alpha 2 by subcutaneous injection, for acute lymphoblastic leukemia or papilloma virus infections. Receptor numbers in PBL in vivo were further reduced concurrent with the progression of IFN therapy. Thus the reduction in IFN receptor expression observed in vitro can be demonstrated in vivo. These studies indicate that monitoring IFN receptor expression in vivo can provide information regarding the availability of IFN receptors at the cell surface for the mediation of IFN actions during the course of IFN therapy.

Dactinomycin↗
PubMed1986

Childhood erythroleukemia. Studies on pathogenesis using colony assays.

Marrow hematopoiesis was examined in two infants with erythroleukemia (EL) using cell culture colony assays. At diagnosis, marrow from both yielded normal to increased numbers of granulocytic colonies (CFU-C), erythroid bursts (BFU-E), and mixed colonies (CFU-GEMM), which contrasted sharply with the reduced growth in eight other newly diagnosed patients with acute leukemia. BFU-E proliferation and hemoglobinization proceeded normally in culture and was entirely erythropoietin-dependent. CFU-C colony cellular composition showed normal granulopoiesis in various stages of development. Despite low numbers of morphologically recognizable blasts in the aspirates, they were readily identified in a blast colony assay because of their high plating efficiency and high index of self-renewal on replating. Blast cells in all cultures had myeloblastic morphology, were peroxidase positive, and expressed the granulocytic-specific My-1 antigen. Monosomy 7 was seen in fresh and cultured blast cells but not in lymphocytes, indicating a clonal proliferation. After chemotherapy-induced remission, blast colonies and monosomy 7 could no longer be detected. It appears that the integrity and function of the normal hematopoietic progenitor pool were preserved in these patients with EL. The abnormal myeloblastic proliferation was expressed actively in colony assays and was useful diagnostically in these cases because marrow morphology was nondiagnostic. In these patients, EL seems to be a misnomer since the findings are suggestive of acute myeloblastic leukemia with secondary erythroid and granulocytic hyperplasia.

Bone Marrow↗
PubMed1986

Induction of differentiation in HL-60 promyelocytic cells: a comparative study in two sublines.

Two variants of HL-60 promyelocytic leukemia cells (HSC, OCI) that were indistinguishable by morphology, cell surface markers, DNA histograms, and by their inability to reduce nitroblue tetrazolium, were induced to differentiate by retinoic acid (RA), 12-O-tetradecanoyl-phorbol-13-acetate (TPA), and by phytohemagglutinin-leucocyte conditioned medium (PHA-LCM). Only OCI cells were induced to differentiate to mature granulocytes by TPA. Both cell lines expressed, however, the monocytic associated cell surface antigen detected by MO1 monoclonal antibody in response to TPA. MO1 expression was detected as early as 32 hours after initiation of differentiation by TPA, whereas partial morphologic changes were apparent only after 72 hours. Induction of differentiation by retinoic acid led to a significant inhibition of colony formation in HSC variant (from 1522 +/- 60 to 523 +/- 20/10(4) cells plated) and in the OCI variant (from 628 +/- 20 to 185 +/- 33 colonies/10(4) cells plated). The addition of PHA-LCM further inhibited colony growth of both RA-induced cell lines (155 +/- 7/10(4) cells plated in HSC, and 59 +/- 4 in OCI). PHA-LCM by itself reduced HL-60 colony numbers in a dose-related manner, and also increased the expression of MO1 on noninduced HSC and OCI cells. These observations suggest that differentiation of HL-60 cells is not necessarily accompanied by concomitant change in morphology, cell surface characteristics, and proliferation potentials, and may be dependent on different degrees of cellular commitment. They also suggest a role for growth factors in the induction to maturation of leukemic cells.

Antibodies, Monoclonal↗
PubMed1986

Characterization of malignant peripheral blood cells of juvenile chronic myelogenous leukemia.

Characterization studies were performed on the malignant peripheral blood cells from three patients with juvenile chronic myelogenous leukemia (JCML) by allowing the cells to increase numerically in liquid cultures. JCML cells proliferated rapidly and excessively in the absence of an added humoral growth factor, whereas control peripheral blood cells declined in number when cultured under identical conditions. Clonality of JCML cells was proven by cytogenetic analysis of the proliferating population. JCML cells were exclusively of monocytic lineage as determined by morphology, staining characteristics, and monoclonal antibody identification of cell-specific surface antigens, but cytochemical and functional studies identified aberrant properties indicating defective differentiation. Striking differences from control cells in ultrastructure and topography were also observed by transmission and scanning electron microscopy. These data provide new information on the cellular origin of JCML and form the basis for further study of leukemic cell biology in this disease.

Child, Preschool↗
PubMed1986

Juvenile chronic myelogenous leukemia: characterization of the disease using cell cultures.

To characterize juvenile chronic myelogenous leukemia (JCML), the proliferative properties of bone marrow (BM) and peripheral blood (PB) cells from nine patients were studied using assays for CFU-C and CFU-GEMM and liquid cultures. All specimens showed two reproducible abnormalities: impaired growth of normal hematopoietic progenitors and excessive proliferation of monocyte-macrophage colonies in the absence of exogenous colony-stimulating activity (CSA). Cytogenetic studies in one patient indicated that the CFU-C were malignant because BM cells at diagnosis and monocyte-macrophage colonies showed an abnormal karyotype, whereas PB lymphocytes did not. In contrast to JCML, PB from six adults with Philadelphia (Ph1) chromosome-positive chronic myelogenous leukemia (Ph1 + CML) yielded CSA-dependent CFU-C colonies which were composed of granulocytes, macrophages, or both, as well as exuberant growth of BFU-E colonies. Co-cultures of JCML BM adherent or nonadherent cells with normal BM resulted in suppression of normal hematopoietic colony formation. Supernatant from JCML adherent cells in liquid culture or plasma from newly diagnosed untreated JCML patients also suppressed control BM colony growth in a dose-dependent manner. These findings confirm that JCML is a malignant disorder of monocytic lineage and suggest that the mechanism of hematopoietic failure in JCML is mediated by an inhibitory monokine secreted by malignant JCML cells.

Bone Marrow Cells↗
PubMed1986

The regulatory role of interleukin 2-responsive T lymphocytes on early and mature erythroid progenitor proliferation.

To analyze the role of T lymphocytes in human erythropoiesis, we evaluated the effect of recombinant interleukin 2 (IL 2) on marrow CFU-E and BFU-E colony formation in vitro. IL 2 resulted in an increase in CFU-E and BFU-E colony numbers in a dose-dependent manner. This increase could be prevented by anti-Tac, a monoclonal antibody to the IL 2 receptor. Moreover, anti-Tac on its own resulted in an overall decrease in colony numbers. Depletion of marrow adherent cells did not alter the effect of either IL 2 or anti-Tac on colony growth. Following the removal of marrow T lymphocytes, CFU-E and BFU-E colony formation proceeded normally; however, the effects of IL 2 and anti-Tac were markedly diminished. Readdition of T lymphocytes to the cultures restored the IL 2 effect. Although T lymphocytes were not themselves essential for in vitro erythropoiesis, our studies suggest that IL 2 and IL 2-responsive T cells can regulate both early and mature stages of erythroid differentiation.

Animals↗
PubMed1985

Prevention of cardiac disease by subcutaneous deferoxamine in patients with thalassemia major.

We examined the efficacy of long-term subcutaneous deferoxamine therapy in the prevention of iron-related cardiac disease in patients with thalassemia major who began treatment after the age of 10 years. Of 36 such patients without preexisting cardiac disease, 19 did not comply with the program of chelation therapy. Over the course of treatment (1977 to 1983) serum ferritin and aspartate aminotransferase levels fell in the compliant group, from mean values (+/- S.D.) of 4765 +/- 2610 to 2950 +/- 1850 ng per milliliter and 58.1 +/- 22 IU to 30 +/- 20 IU per liter, respectively (P less than 0.05), but rose in the noncompliant group, from 5000 +/- 2316 to 6040 +/- 2550 ng per milliliter and 56.6 +/- 20 to 90 +/- 35 IU per liter, respectively. Only one patient in the compliant group acquired cardiac disease and died of fulminant congestive heart failure. In contrast, 12 noncompliant patients acquired cardiac disease, and 7 died. In addition, the mean age of the compliant population (18.9 +/- 4.5 years) now approaches the mean age of acquisition of cardiac disease in the noncompliant group (19 +/- 4.3). These data demonstrate that compliance with treatment with deferoxamine may protect patients from cardiac disease induced by iron overload.

Adolescent↗
PubMed1985

Separation of lymphoid and myeloid blasts in the mixed blast crisis of chronic myelogenous leukemia: no evidence for Ig gene rearrangement in CALLA-positive blasts.

Recent studies suggest that lymphoid blast crisis cells of chronic myelogenous leukemia (CML) expressing the common acute lymphoblastic leukemia antigen (CALLA) are B precursor cells, based on the demonstration of immunoglobulin (Ig) gene rearrangement similar to common acute lymphocytic leukemia. There is little evidence to suggest whether the cells with similar lymphoid characteristics in the mixed blast crisis of CML are also committed to B cell lineage. A patient in "mixed" blast crisis of CML was studied. On the basis of morphology, cytochemistry, and immunological studies, the blasts were classified as having either lymphoid or myeloid characteristics. A proportion of the leukemic blasts expressed CALLA, whereas others expressed My7 antigen. In order to characterize both populations of cell further, CALLA+ blasts and My7+ (myeloid) blasts were isolated by fluorescence-activated cell sorting. The My7+ cells were highly proliferative in cell culture blast colony assays, retained the Ph1 chromosome, and were indistinguishable from acute myelogenous leukemia blasts. The CALLA+ cells were also Ph1-chromosome positive, but in contrast, were poorly proliferative in vitro. Of particular note was their retention of germline configuration of Ig genes, thus distinguishing them from blasts in the lymphoid crisis of CML. We conclude that the lymphoid component in mixed blast crisis may represent a stage of differentiation prior to commitment to B lineage.

Adolescent↗
PubMed1985

Growth inhibitory effect of gene-cloned interferons on human myeloblast colonies.

The effect on marrow myeloblast colony formation in blood from nine patients with acute myeloid leukemia was studied by using three recombinant-DNA-derived human leukocyte interferons (IFN alpha 2, IFN alpha-A, and IFN alpha-C). In preliminary experiments, a brief exposure of leukemic marrow cells to IFN alpha resulted in a sharp increase in the IFN-induced enzyme 2-5A synthetase, indicating the expression of IFN cell receptors as well as the ability of leukemia cells to respond metabolically. Dose-response studies showed a dose-dependent suppression of myeloblast colony formation in all experiments using concentrations of 10(2)-10(5) U/ml of the three IFN subtypes. In self-renewal assays derived from the primary cultures that initially contained IFN alpha 2, a "carryover" antiproliferative effect was observed with a dose-dependent decline in secondary growth. In comparison studies of IFN alpha-A and IFN alpha-C, the suppressive effect on primary myeloblast growth was much more pronounced with IFN alpha-C at concentrations of 10(3) U/ml and higher; in self-renewal assays, the antiproliferative effect of IFN alpha-C on secondary growth was no longer observed, whereas that of IFN alpha-A persisted. These three subtypes of gene-cloned IFN have antileukemic properties in vitro, with differences in degree of suppression of primary myeloblast growth and of self-renewal.

2',5'-Oligoadenylate Synthetase↗
PubMed1984

Congenital failure of hematopoiesis in the newborn infant.

Hematopoietic stem cell cultures have greatly advanced our understanding of the physiology of blood production at its early stages and have facilitated the study of various factors that regulate cell differentiation and proliferation. With this understanding, the author discusses hematopoiesis, hematopoietic stem cells and assays for their study, and hematopoietic failure. This is followed by a discussion of different forms of bone marrow failure and guidelines for a rational basis for their therapy.

Anemia, Aplastic↗
PubMed1984

Deferoxamine: a reversible S-phase inhibitor of human lymphocyte proliferation.

Deferoxamine is widely used therapeutically as a chelator of ferric ion in disorders of iron overload. This study demonstrates that this drug is a potent inhibitor of DNA synthesis by human B and T lymphocytes in vitro, but has relatively little effect on the synthesis of RNA and protein. The inhibitory effects of deferoxamine are completely reversible by washing or by adding stoichiometric amounts of Fe3+. Micromolar concentrations of deferoxamine decrease intracellular levels of deoxyribonucleoside triphosphates, which is similar to the effects of hydroxyurea. The binding of iron by deferoxamine likely causes an inhibition of ribonucleotide reductase activity, thereby preventing cells from completing the S phase of the cell proliferation cycle. As a reversible and nontoxic S-phase inhibitor, it may have important experimental and therapeutic applications.

Adolescent↗