bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fibroblasts induce heparin synthesis in chondroitin sulfate E containing human bone marrow-derived mast cells
Authors: Gilead L , Bibi O , Razin E 
Published: October 2019

Abstract
Human bone marrow-derived mast cells (hBMMCs), differentiated in vitro in suspension culture and under the influence of human peripheral blood mononuclear cells conditioned medium (hCM), were tested for their response to recombinant human interleukin-3 (rhIL-3) and for their behavior in different microenvironments. The hBMMCs were incubated in the presence of rhIL-3 and the changes in their proliferation rate were determined. Recombinant hIL-3 induced a more than sixfold increase in 3H-thymidine uptake into the hBMMC DNA in a dose-dependent manner. Human CM used as a control for proliferation response induced a more than eightfold maximal proliferation rate increase. Rabbit anti-rhIL-3 completely inhibited hBMMC 3H-thymidine uptake induced by rhIL-3 and decreased the hCM-induced proliferation by approximately 50%. These hBMMCs were cocultured with four different mytomicin C-treated cell monolayers and assayed for phenotypic changes. After only 2 days in coculture with either embryonic mouse skin-derived fibroblasts (MESFs) or human skin-derived fibroblasts (HSFs), a marked increase in granule number and density was noted on staining with toluidine blue. Mast cells that initially stained alcian blue+/safranin- at day 0 of coculture became alcian blue+/safranin+ during the coculture period. Human BMMC proteoglycan synthesis shifted from approximately 85% chondroitin sulfate E to approximately 60% heparin within 14 to 19 days of coculture with the MESF monolayer and to approximately 50% heparin within 19 days of coculture with the HSF monolayer. None of the above- mentioned changes were noted in cocultures of hBMMCs with 3T3 cell line fibroblast monolayers or in cocultures with bovine vascular endothelium (BVE) cell monolayers. These results demonstrate microenvironmental effects exerted by the MESF and HSF monolayers on IL-3-dependent hBMMCs similar to those reported in the conversion of murine mast cell phenotype.
Development and characterization of a cyclophosphamide-resistant subline of acute myeloid leukemia in the Lewis x Brown Norway hybrid rat
Authors: Koelling TM , Yeager AM , Hilton J , Haynie DT , Wiley JM 
Published: October 2019

Abstract
Preclinical studies of resistance to alkylating agents in the Lewis x Brown Norway hybrid (LBN) rat model of acute myeloid leukemia (AML) have hitherto been limited by the sensitivity of LBN AML cells to cyclophosphamide (CY). We developed a CY-resistant subline of LBN AML by serial intravenous (IV) passage of AML cells followed by in vivo exposure to CY (100 mg/kg) 14 days later. After 18 and subsequent passages, CY-treated AML cells remained viable despite ex vivo incubation with 70 to 100 mumol/L 4-hydroperoxycyclophosphamide (4HC) or in vivo exposure to 100 to 300 mg/kg of CY. Once established, resistance to incubation with 4HC was stable in LBN AML cells after at least six serial in vivo passages without exposure to CY. Nevertheless, both control and CY-treated AML cells demonstrated similar dose- dependent sensitivity to 100 to 500 mumol/L phosphoramide mustard (PhM), the active alkylating end-product of CY activation in vivo. Levels of aldehyde dehydrogenase (ALDH), which inactivates CY by prevention of formation of PhM, were significantly elevated in these CY- resistant AML cells: cytosolic and particulate ALDH fractions from these cells were 11 to 13 times control with NAD cofactor and propanal substrate and three to four times control with NADP cofactor and benzaldehyde substrate. Further studies with this animal model of AML, in which resistance to CY is mediated by elevated ALDH activity, may elucidate mechanisms for effective elimination of drug-resistant leukemic cells ex vivo and in vivo.
Inhibition of phorbol ester-induced monocytic differentiation and c-fms gene expression by dexamethasone: potential involvement of arachidonic acid metabolites
Authors: Stone RM , Imamura K , Datta R , Sherman ML , Kufe DW 
Published: October 2019

Abstract
The treatment of human U-937 leukemia cells with 12-O- tetradecanoylphorbol-13-acetate (TPA) is associated with induction of monocytic differentiation. However, the signaling pathways responsible for induction of the differentiated monocytic phenotype remain unclear. The present studies demonstrate that dexamethasone blocks TPA-induced U- 937 cell growth inhibition, adherence, and alpha-naphthyl acetate esterase staining. The results also demonstrate that dexamethasone inhibits the appearance of c-fms transcripts associated with TPA treatment. Run-on transcription assays demonstrated that the c-fms gene is transcriptionally active in uninduced U-937 cells and that the rate of transcription is unchanged after dexamethasone and/or TPA treatment. These findings indicated that TPA increases c-fms expression by a dexamethasone-sensitive posttranscriptional mechanism. Treatment of U- 937 cells with TPA was also associated with stimulation of arachidonic acid metabolism. Furthermore, dexamethasone, an inhibitor of phospholipase A2 activity, blocked TPA-induced increases in arachidonic acid release. These findings suggested that TPA may regulate certain features of monocytic differentiation, such as c-fms gene expression, through the formation of arachidonic acid metabolites. Indomethacin, an inhibitor of cyclooxygenase, had no detectable effect on c-fms gene expression. However, the cyclooxygenase metabolite, prostaglandin E2, inhibited the TPA-induced increases in c-fms mRNA levels. Taken together, the results indicate that TPA regulates c-fms gene expression by a dexamethasone-sensitive mechanism and that c-fms mRNA levels are controlled by metabolites of the arachidonic acid pathway.
Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro
Authors: Whitehead S , Peto TE 
Published: October 2019

Abstract
Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.
Induction of mixed erythroid-megakaryocyte colonies and bipotential blast cell colonies by recombinant human erythropoietin in serum-free culture
Authors: Nishi N , Nakahata T , Koike K , Takagi M , Naganuma K , Akabane T 
Published: October 2019

Abstract
The effects of recombinant human erythropoietin (rEp) on murine hematopoietic progenitors were studied using a serum-free culture. A high concentration of rEp stimulated the formation of mixed erythroid- megakaryocyte colonies (EM colonies) and blast cell colonies, as well as erythroid colonies, erythroid bursts, and megakaryocyte colonies from normal mouse bone marrow cells. Direct effects of rEp on EM colony, megakaryocyte colony, and erythroid burst formation were confirmed by depletion of accessory cells such as T cells, B cells, and macrophages from crude bone marrow cells, and inhibition of the colonies by the addition of rabbit anti-rEp antibody to the culture in a dose-dependent fashion. Replating experiments were performed to confirm the differentiating ability of blast cell colonies grown in the presence of rEp. Most of the blast cell colonies yielded not only secondary erythroid colonies but also megakaryocyte colonies in the presence of 2 IU/mL rEp. Some of the blast cell colonies produced secondary EM colonies in the presence of 16 IU/ml rEp of 2 IU/mL rEp plus interleukin-3, although no granulocyte-macrophage colonies were found in the secondary culture. These results suggest that Ep acts not only as a late-acting factor that is specific for erythroid progenitors, but also as a bipotential EM-stimulating factor for murine hematopoietic cells.
Expression of transcobalamin II receptors by human leukemia K562 and HL- 60 cells
Authors: Amagasaki T , Green R , Jacobsen DW 
Published: October 2019

Abstract
Plasma membrane receptors for the serum cobalamin-binding protein transcobalamin II (TCII) were identified on human leukemia K562 and HL- 60 cells using immunoaffinity-purified human TCII labeled with [57Co]cyanocobalamin. The Bmax values for TCII receptors on proliferating K562 and HL-60 cells were 4,500 and 2,700 per cell, respectively. Corresponding dissociation constants (kd) were 8.0 x 10(- 11) mol/L and 9.0 x 10(-11) mol/L. Rabbit TCII also bound to K562 and HL-60 cells but with slightly reduced affinities. Calcium was required for the binding of transcobalamin II to K562 cells. Brief treatment of these cells with trypsin resulted in almost total loss of surface binding activity. After removal of trypsin, surface receptors for TCII slowly reappeared, reaching pretrypsin treatment densities only after 24 hours. Reappearance of receptors was blocked by cycloheximide. TCII receptor densities on K562 and HL-60 cells correlated inversely with the concentration of cobalamin in the culture medium. This suggests that intracellular stores of cobalamin may affect the expression of transcobalamin receptors. Nonproliferating stationary-phase K562 cells had low TCII receptor densities (less than 1,200 receptors/cell). However, the density of TCII receptors increased substantially when cells were subcultured in fresh medium. Up-regulation of receptor expression coincided with increased 3H-thymidine incorporation, which preceded the resumption of cellular proliferation as measured by cell density. In the presence of cytosine arabinoside, which induces erythroid differentiation, K562 cells down-regulated expression of TCII receptors. When HL-60 cells were subcultured in fresh medium containing dimethysulfoxide to induce granulocytic differentiation, the up- regulation of TCII receptors was suppressed. This event occurred well before a diminution of 3H-thymidine incorporation and cessation of proliferation. Thus, changes in the regulation of expression of TCII receptors correlate with both the proliferative and differentiation status of cells.
Release of tumor necrosis factor by human polymorphonuclear leukocytes
Authors: Djeu JY , Serbousek D , Blanchard DK 
Published: October 2019

Abstract
Evidence is presented that human polymorphonuclear neutrophils (PMN) can be induced to produce tumor necrosis factor (TNF). Other investigators have previously reported that TNF has been induced from macrophages by bacteria and, more recently, from natural killer cells by certain tumor cells. Our laboratory has reported that the opportunistic fungi, Candida albicans, can induce TNF, not only from human monocytes, but also from Percoll-fractionated large granular lymphocytes. We now report that incubation of PMN with C albicans for 3 hours was sufficient for detection of TNF release, and peak induction was observed at 8 to 18 hours. This release was inhibitable by actinomycin D, an inhibitor of RNA synthesis, as well as by emetine and cycloheximide, which block protein synthesis. The TNF produced by PMN was neutralized by specific monoclonal antibodies against human TNF. These results represent an important finding that TNF production is a normal response of PMN to stimulation by fungi such as C albicans and suggest that the release of TNF may be related to autocrine activation of PMN effector function to control Candida growth.
Anti-asialo GM1 antiserum treatment of lethally irradiated recipients before bone marrow transplantation: evidence that recipient natural killer depletion enhances survival, engraftment, and hematopoietic recovery
Authors: Tiberghien P , Longo DL , Wine JW , Alvord WG , Reynolds CW 
Published: October 2019

Abstract
Natural killer (NK) cells are reported to have an important role in the resistance of lethally irradiated recipients to bone marrow transplantation (BMT). Therefore, we investigated the effects of recipient NK depletion on survival, chimerism, and hematopoietic reconstitution after lethal irradiation and the transplantation of limiting amounts of T-cell-deficient bone marrow (BM). When administered before BMT, anti-asialo GM1 (ASGM1) antiserum treatment, effective in depleting in vivo NK activity, was associated with a marked increase in survival in 3 of 3 allogeneic combinations (BALB/c into C3H/HeN, C57B1/6, or C3B6F1). This enhanced survival was independent of the susceptibility of each recipient strain to accept BALB/c BM. Moreover, recipient anti-ASGM1 treatment was also effective in increasing survival in recipients of syngeneic BM, suggesting that NK cells can adversely affect engraftment independent of genetically controlled polymorphic cell surface determinants. Analysis of chimerism in surviving animals 2 months post-BMT showed that recipient NK depletion significantly increased the level of donor engraftment when high doses of BM were transplanted. These studies also demonstrated that anti-ASGM1 pretreatment mainly resulted in an increase in extramedullary hematopoiesis in the second and third week after irradiation. Anti-ASGM1 treatment also dramatically accelerated the rate of appearance of donor-derived cells with a higher level of donor- cell engraftment apparent at a time when the differences in survival between NK-depleted and control BMT recipients became significant. Peripheral cell counts were also affected by NK depletion, with significantly enhanced platelet and red blood cell recovery and a moderate increase in granulocyte recovery. The overall favorable influence of anti-ASGM1 recipient treatment on hematopoietic events post-BMT suggests that, in humans, pretransplant regimens aimed toward NK depletion should be evaluated.
In vivo stimulation of megakaryocytopoiesis by recombinant murine granulocyte-macrophage colony-stimulating factor
Authors: Vannucchi AM , Grossi A , Rafanelli D , Ferrini PR 
Published: October 2019

Abstract
Murine recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) was injected in mice, and the effects on bone marrow, splenic megakaryocytes, megakaryocyte precursors (megakaryocyte colony-forming units [CFU-Meg]) were evaluated. In mice injected three times a day for 6 days with 12,000 to 120,000 U rGM-CSF, no significant modification of both platelet levels and mean platelet volume was observed, while there was a twofold increase in blood neutrophils. However, the rate of platelet production, as assessed by the measurement of 75selenomethionine incorporation into blood platelets, was On the contrary, administration of up to 384,000 U rGM-CSF two times a day for 2 days, as for a typical “thrombopoietin assay,” failed to modify platelet production. A significant dose-related increase in the number of splenic megakaryocytes occurred in mice receiving 60,000 to 120,000 U rGM-CSF, while a slight increase in the number of bone marrow megakaryocytes was observed in mice injected with 120,000 U rGM-CSF. The proportion of bone marrow megakaryocytes with a size less than 18 microns and greater than 35 microns resulted significantly higher in mice receiving rGM-CSF in comparison with controls; an increase in the percentage of splenic megakaryocytes greater than 35 microns was also observed. A statistically significant increase in the total spleen content of CFU-Meg was observed after administration of 90,000 and 120,000 U rGM-CSF three times a day for 6 days, while no effect on bone marrow CFU-Meg was recorded, irrespective of the dose delivered. Finally, 24 hours after a single intravenous injection of rGM-CSF, there was a significant increase in the proportion of CFU-Meg in S- phase, with the splenic progenitors being more sensitive than bone marrow-derived CFU-Meg. These data indicate that rGM-CSF has in vivo megakaryocyte stimulatory activity, and are consistent with previous in vitro observations. However, an effective stimulation of megakaryocytopoiesis in vivo, bringing about an increase in the levels of blood platelets, may require interaction of rGM-CSF with other cytokines.
Coordinate secretion of interleukin-1 beta and granulocyte-macrophage colony-stimulating factor by the blast cells of acute myeloblastic leukemia: role of interleukin-1 as an endogenous inducer
Authors: Rodriguez-Cimadevilla JC , Beauchemin V , Villeneuve L , Letendre F , Shaw A , Hoang T 
Published: October 2019

Abstract
Acute myeloblastic leukemia (AML) blasts have been shown to produce a variety of cytokines in culture such as interleukin-1 (IL-1), IL-6, granulocyte-, macrophage-, and granulocyte-macrophage colony- stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF alpha). Using two sensitive and specific enzyme-linked immunosorbent assays for IL-1 beta and GM-CSF, we document in the present study that the production of the two cytokines by AML blasts in culture is coordinated. First, we observe a striking correlation between the levels of GM-CSF and IL-1 beta released by the cells. Thus, a high production of IL-1 beta is always concordant with a high production of GM-CSF and, conversely, low production of IL-1 beta is concordant with low levels of GM-CSF. Second, neutralization of intrinsic IL-1 using antibodies that are specific for IL-1 alpha and -1 beta suppresses the release of GM-CSF by the cells. Third, neutralization of the endogenous source of IL-1 also results in an abrogation of GM-CSF mRNA. Fourth, the production of both IL-1 beta and GM-CSF is up-regulated by exposing AML blasts to an exogenous source of IL-1, suggesting a positive regulation of autocrine growth factor production. Taken together, our results indicate that GM-CSF production by AML blasts is mediated by endogenously produced IL-1. Both IL-1 beta and -1 alpha are produced by AML blasts, although IL-1 beta appears to be more abundant. Spontaneous colony formation by AML blasts is abrogated by the addition of neutralizing antibodies against IL-1 beta and GM-CSF, whereas each antibody alone has little effect on blast proliferation. Taken together, our results are consistent with the view that the production of IL-1 beta by AML blasts supports autocrine growth in culture, through induction of CSFs or other cytokines that stimulate blast proliferation.
The pharmacokinetics of plasminogen activator inhibitor-1 in the rabbit
Authors: Mayer EJ , Fujita T , Gardell SJ , Shebuski RJ , Reilly CF 
Published: October 2019

Abstract
The pharmacokinetics of the activated and latent forms of plasminogen activator inhibitor-1 (PAI–1) isolated from HT1080 fibrosarcoma cells (HT1080 PAI-1) and a nonglycosylated form of human PAI-1 isolated from a yeast expression system (rPAI-1) were followed in the rabbit. As assessed by an immunologic assay specific for human PAI-1, guanidine HCI activated HT1080 PAI-1 and rPAI-1 entered the total plasma volume following intravenous bolus administration and exhibited a biphasic clearance pattern. The t1/2s of HT1080 PAI-1 for the initial and beta phases equalled 6.0 and 24.8 minutes, respectively. The t1/2s of rPAI-1 for the initial and beta phases equalled 8.8 and 34.0 minutes, respectively. Similar results were obtained by measuring PAI-1 activity in plasma and with trace amounts of 125I-rPAI-1, suggesting that the above pharmacokinetic behavior could also apply to endogenous PAI-1. The liver was the main site of rPAI-1 clearance. Unactivated, latent PAI-1 exhibited a very different pharmacokinetic profile. Over 80% of latent rPAI-1 cleared from the circulation within 10 minutes (t1/2 = 1.7 minutes). The difference in clearance behavior between activated and latent PAI-1 may be related to the ability of activated PAI-1, but not latent PAI-1, to rapidly form high-molecular-weight complexes with plasma binding factors which were observed in vitro and in vivo. Because PAI-1 could potentially tilt the fibrinolytic balance toward a prothrombotic state, its rapid clearance may represent an important control mechanism governing the circulating levels of this key component of the fibrinolytic pathway.
The hematopoietic defect in aplastic anemia assessed by long-term marrow culture
Authors: Marsh JC , Chang J , Testa NG , Hows JM , Dexter TM 
Published: October 2019

Abstract
Thirty-two patients with aplastic anemia (AA) have been studied using the long-term bone marrow culture (LTBMC) system. Of these patients, 26 had been treated with immunosuppressive therapy including antilymphocyte globulin (ALG) with or without androgens or high-dose methyl prednisolone. The remaining six patients either required no treatment or were studied before therapy was begun. Thirty-one of 32 patients (96%) had defective hematopoiesis in LTBMC with little or no evidence for the generation of primitive progenitor cells. The only exception was a patient with spontaneous recovery of aplasia in whom the defect was less marked. Crossover LTBMC experiments were performed in 23 cases by inoculating (1) patient marrow hematopoietic cells that had been depleted of adherent cells onto preformed, irradiated, normal stromas to assess the proliferative capacity of the hematopoietic cells, and (2) normal marrow hematopoietic cells that were depleted of adherent cells onto preformed, irradiated stromas from patients with AA to assess stromal function. Results of these experiments demonstrated a hematopoietic defect in all patients that was independent of the degree of hematologic recovery after ALG therapy. Only one patient had a probable stromal defect and this coexisted with a defect in the regenerative capacity of hematopoietic cells. We conclude that LTBMC is a sensitive method for detecting and defining the hematopoietic failure in AA. We suggest that the defective hematopoiesis present in all patients studied may be important in the pathogenesis of clonal evolution in AA.