bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein kinase C activators can interact synergistically with granulocyte colony-stimulating factor or interleukin-6 to stimulate colony formation from enriched granulocyte-macrophage colony-forming cells
Authors: Heyworth CM , Dexter TM , Nicholls SE , Whetton AD 
Published: October 2019

Abstract
The effects of direct activators of protein kinase C (PKC) (the phorbol ester tetradecanoyl phorbol myristic acid [TPA] or bryostatin) on the ability of a highly enriched population of granulocyte-macrophage colony-forming cells (GM-CFC) to proliferate and develop in soft agar was assessed. In the absence of colony stimulating factors, the PKC activators did not stimulate colony formation. However, in the presence of optimal concentrations of granulocyte colony-stimulating factor (G- CSF) or interleukin-6 (IL-6), TPA or bryostatin markedly elevated the number of colonies formed from the GM-CFC. In the absence of TPA, IL-6, and G-CSF, respectively, both stimulated the formation of about 3% of the colonies observed when IL-3 was present. When TPA plus G-CSF or IL- 6 were added together, this figure increased to 48% and 54%, respectively. In both instances, the types of mature cells formed was altered from colonies of mature neutrophilic cells to a mixture consisting predominantly of macrophages with some neutrophils. Similar results were observed when bryostatin replaced TPA in these assays. When single cell colony-forming assays were performed, the same results were obtained. The presence of G-CSF, or IL-6, and the activator of PKC used (TPA or bryostatin) was required throughout the colony-forming assay for an optimal synergistic effect to be observed. These data indicate that agents that activate PKC can promote the proliferation and development of GM-CFC via a synergistic interaction with G-CSF or IL-6. Furthermore, there is an apparent role for PKC in development and possibly lineage commitment of GM-CFC.
T- and B-lymphocyte differentiation potentials of spleen colony-forming cells
Authors: Lepault F , Ezine S , Gagnerault MC 
Published: October 2019

Abstract
Cells that generate splenic colonies within 8 days (day-8 colony- forming units-spleen [CFU-s]) are generally thought to differentiate only into erythroid/myeloid cells. The T and B lymphocyte differentiation potentials of day-8 CFU-s were evaluated and compared with those of day-12 and 5-fluorouracil (5-FU) CFU-s. This was achieved by analyzing, after intravenous and intrathymic injection, the lymphocyte progeny of cells contained within individual splenic colonies collected at day 8 and day 12 post-bone marrow cell transfer into irradiated congenic recipients. A large majority of day-8 spleen colonies generated T cells when transferred intrathymically. After intravenous (IV) injection of day-8 colonies, donor-type thymocytes emerged in 33% of the animals reconstituted with only 1 day-8 colony, but in 83% of those inoculated with a pool of 5 colonies. All post-5-FU and 75% of day-12 colonies gave rise to thymocytes after IV injection. B cells were generated by a high proportion of day-8 colonies, and by all day-12 and post 5-FU colonies. These results demonstrate that progenitors of T and B lymphocytes are generated within spleen colonies produced by at least some day-8 CFU-s and virtually all day-12 CFU-s. Whether these progenitors are CFU-s themselves or committed precursors remains an open question.
The kinetics of plasminogen activation by thrombin-cleaved pro- urokinase and promotion of its activity by fibrin fragment E-2 and by tissue plasminogen activator
Authors: Liu JN , Gurewich V 
Published: October 2019

Abstract
Thrombin hydrolyzes the Arg156-Phe157 bond in pro-urokinase (pro-UK), two residues from the activation site, generating a two-chain form (thromb-UK) believed to have little activity and that is resistant to plasmin activation. The kinetic constants for thromb-UK against synthetic substrate (S2444) were found to be essentially identical to pro-UK. Against native plasminogen, thromb-UK had a lower Michaelis constant (KM) and a higher (2-fold) catalytic efficiency. However, this difference with pro-UK was nullified by carboxypeptidase B (CpB) treatment of thromb-UK to remove the C-terminal arginine on the A- chain. Plasminogen activation by thromb-UK was substantially promoted by fibrin fragment E-2 but not by other fibrin derivatives, a phenomenon previously observed with pro-UK. Similarly, clot lysis by thromb-UK was promoted by tissue plasminogen activator because their combined effect was synergistic. Fibrinogenolysis in plasma occurred at 80-fold the concentration of thromb-UK as pro-UK, reflecting the 90- fold greater plasmin resistance of thromb-UK. Addition of a CpB inhibitor to the plasma enhanced fibrinogenolysis by thromb-UK and pro- UK by approximately 16%, consistent with the promotion of both forms by certain C-terminal lysines. In conclusion, CpB-thromb-UK corresponds functionally to a plasmin resistant form of pro-UK, indicating that the catalytic site of the single-chain pro-UK is unaffected by thrombin cleavage. The effect of CpB indicates that the C-terminal Arg of thromb- UK slightly enhances its affinity for plasminogen. Thromb-UK has potential plasminogen-activating activity at surfaces where C-terminal lysines, functionally comparable to fragment E-2, are found.
Defective signal transduction induced by thromboxane A2 in a patient with a mild bleeding disorder: impaired phospholipase C activation despite normal phospholipase A2 activation
Authors: Fuse I , Mito M , Hattori A , Higuchi W , Shibata A , Ushikubi F , Okuma M , Yahata K 
Published: October 2019

Abstract
A patient with a mild bleeding disorder whose platelets responded defectively to thromboxane A2 (TXA2) was identified, and the mechanism of this dysfunction was analyzed. The platelets were defective in shape change, aggregation, and release reaction in response to synthetic TXA2 mimetic (STA2). When the platelet TXA2 receptor was examined with both a 125I-labeled derivative of a TXA2 receptor antagonist ([125I]-PTAOH) and [3H]-labeled TXA2 agonist ([3H]U-46619), the equilibrium dissociation rate constants (kd) and the maximal concentrations of binding sites (Bmax) of the platelets to both ligands were within normal ranges, suggesting that the binding capacity of their TXA2 receptor was normal. STA2 could not induce IP3 formation and intracellular Ca2+ mobilization, whereas these responses to thrombin were within normal ranges. GTPase activity was also decreased when the patient's platelet membrane was challenged with STA2. On the other hand, lysophosphatidylinositol formation, which is a direct indicator of phospholipase A2 (PLA2) activation, was found to be normal when the [3H]-inositol-labeled platelets were challenged with STA2. Thromboxane B2 (TXB2) was also produced in response to STA2. These results suggested that the abnormality in these platelets was impaired coupling between TXA2 receptor and phospholipase C (PLC) activation. Furthermore, it is also suggested that the activation of PLA2 and PLC are separable events in thromboxane-induced platelet activation.
Monoclonal antibody J11d.2 recognizes cell cycle-dormant, primitive hematopoietic progenitors of mice
Authors: Shih JP , Ogawa M 
Published: October 2019

Abstract
It was reported that monoclonal antibody (MoAb) J11d.2 reacts with mature blood cells of mice but not with their progenitors. We tested in culture studies whether this antibody could be used for enrichment for primitive marrow progenitors. The majority of colony-forming cells including multipotential progenitors in the marrow cells from 5- fluorouracil (5-FU)-treated mice were J11d.2+, whereas most of the progenitors from normal mice were J11d.2-. In addition, formation of multilineage colonies from J11d.2+ in both 5-FU-treated and normal mice was augmented by interleukin 6. These observations indicated that MoAb J11d.2 recognizes cell cycle-dormant progenitors. We have recently described a simple method that provides 800-fold enrichment for the progenitors in post-5-FU marrow cells using MoAb D7 (anti-Ly-6A/E). When this method was modified to include sorting with MoAb J11d.2, D7+ J11d.2+ cells were 2,250-fold enriched for multipotential progenitors. Micromanipulation and culture of individual D7+ J11d.2+ cells showed that average plating efficiency of the cell population is approximately 70% and that about 30% of the progenitors are lymphohematopoietic in nature. These data demonstrate that J11d.2 is a useful MoAb for the isolation of primitive hematopoietic progenitors of mice.
Effects of immunosuppressants, FK506, deoxyspergualin, and cyclosporine A on immature human hematopoiesis
Authors: Hirao A , Kawano Y , Takaue Y 
Published: October 2019

Abstract
Effects of the immunosuppressants, FK506, deoxyspergualin (DSG), and cyclosporine A (CsA) on the growth of human hematopoietic progenitor cells were tested in the presence of interleukin-3 (IL-3) with purified bone marrow and blood cells as targets in methylcellulose culture. FK506 had a significant stimulatory effect on the growth of colony- forming units/granulocyte-macrophage (CFU-GM) and burst-forming units/erythroid (BFU-E) from peripheral blood and cord blood cells but not from bone marrow cells. Neither DSG nor CsA had an effect on any type of target cell. Liquid-suspension-limiting dilution assay with IL- 3 showed that FK506 directly stimulated the growth of blood progenitors in a dose-dependent manner with single-hit kinetics. Liquid-suspension preincubation of blood cells with FK506 before culture in methylcellulose induced a significant increase in the amount of IL-3- supported growth of CFU-GM and BFU-E, whereas initial preincubation with IL-3 and subsequent culture with FK506 plus IL-3 exerted its stimulatory effect only on BFU-E. These data suggest that the stimulation of hematopoietic progenitor cells by FK506 occurs at a very early stage of maturation and diminishes with further myeloid development.
Cooperative effects of interleukin-3 (IL-3), IL-5, and granulocyte- macrophage colony-stimulating factor: a new myeloid cell line inducible to eosinophils
Authors: Paul CC , Tolbert M , Mahrer S , Singh A , Grace MJ , Baumann MA 
Published: October 2019

Abstract
The cytokines interleukin-3 (IL-3); IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are known to contribute to the proliferation and differentiation of eosinophil progenitors. Recently, it was determined that the cellular receptors for these three cytokines share a common beta-chain while having unique alpha-chains. Thus, there is considerable interest in how these cytokines and their receptors interact in promoting production of eosinophils. We have established a cell line (AML14) from a patient with acute myelogenous leukemia that will consistently exhibit eosinophilic differentiation in suspension in response to IL-3, IL-5, and GM-CSF. Proliferation with only modest differentiative effects was observed in response to a single cytokine. Combinations of two cytokines gave variable results, with GM-CSF + IL-3 and IL-3 + IL-5 causing more proliferation than a single cytokine but little more differentiation. The combination of GM-CSF + IL-5 caused marked enhancement of eosinophilic differentiation with only modest augmentation of proliferation. The combination of all three cytokines was most effective in stimulating both proliferation and eosinophilic differentiation (up to 70% of cells) of AML14 cells. Specific binding of GM-CSF and IL-5 to AML14 cells can be conveniently studied by flow cytometric methods, and cross-competition of these two cytokines for their respective receptors was demonstrated. IL-3 was shown to partially compete for IL-5 binding on AML14 cells. Although specific IL- 3 binding could not be demonstrated by flow cytometry, mRNA for the alpha-chains of the IL-3, IL-5, and GM-CSF receptors and the beta-chain common to all three receptors was detected in AML14 cells. The AML14 cell line may be a useful model for the study of cooperative interactions of IL-3, IL-5, GM-CSF, and their respective receptors in the promotion of eosinophil progenitor growth and differentiation.
Dissecting the hematopoietic microenvironment. IX. Further characterization of murine bone marrow stromal cells
Authors: Penn PE , Jiang DZ , Fei RG , Sitnicka E , Wolf NS 
Published: October 2019

Abstract
We have previously shown the adherent nontransformed, nonimmortalized murine bone marrow stromal cell (BMSC) population to consist of phagocytic macrophage and endothelial-like cells and nonphagocytic fibroblasts. Both colonial and near confluent growth of each cell type was obtained following magnetic bead separation, subsequent passaging, and sustained culture with fetal bovine serum and cytokines. Monoclonal antibody staining of antigenic determinants was used to characterize the phenotype of the stromal cell population in primary platings of murine colony-forming unit fibroblast and long-term bone marrow cultures. The antibodies MECA-99, MECA-32, and MJ7–18, raised against murine vascular endothelial antigenic determinants, and von Willebrand's factor all stained selectively for the rounded endothelial- like cells. Endothelial-like cells as well as macrophages expressed the myeloid surface antigens F4/80, 7/4, and Mac-1 under our culture conditions. The cytoskeleton of the stromal fibroblasts in culture was shown to express smooth muscle-specific actin isoforms, as evidenced by positive staining of stress fibers for alpha smooth muscle-1, CGA-7 (alpha/gamma isoforms), and HHF-35 (recognizes all muscle-specific actins). Under culture conditions, stromal fibroblasts were also found to be positive for a polyclonal smooth muscle myosin. It was found that these fibroblasts stained for collagens type I, III, and IV in our cultures. Although collagen type IV is considered a by-product of endothelial cells, endothelial-like cells in our cultures did not stain for any of the collagen types. We propose a classification listing for murine BMSCs as macrophages, endotheliallike cells, and fibroblasts that display smooth muscle-like characteristics in culture.
Downregulation of GATA-1 expression during phorbol myristate acetate- induced megakaryocytic differentiation of human erythroleukemia cells
Authors: Dai W , Murphy MJ Jr 
Published: October 2019

Abstract
Phorbol myristate acetate (PMA) induces the expression of megakaryocyte and/or platelet proteins during terminal differentiation of human erythroleukemia (HEL) cells. However, it is not established whether megakaryocytic differentiation is accompanied by the downregulation of the major erythroid transcription factor GATA-1 and the concomitant loss of the erythrocytic phenotype. Studies of the molecular mechanism of PMA-induced differentiation in HEL cells showed that when HEL cells are treated with PMA, they dramatically decrease the expression of the erythroid-specific gene glycophorin A at the mRNA level but apparently not at the steady-state protein level. In addition, a gel mobility shift assay was used to demonstrate that GATA-1, a major erythroid transcription factor normally present at high levels in HEL cells is downregulated after treatment with PMA. In contrast, the DNA-binding activities of transcription factors AP-1 and SP-1 are upregulated by PMA treatment of HEL cells. Furthermore, Northern blot analysis shows that PMA also downregulates the steady-state level of GATA-1 mRNA in HEL cells. The coordinated negative regulation of glycophorin A mRNA and GATA-1 expression after PMA treatment suggests that downregulation of GATA-1 expression may be partially responsible for the loss of the erythroid phenotype during megakaryocytic differentiation. The reported data also suggest that GATA-1 activity may not be essential for obtaining megakaryocytic phenotype during terminal differentiation in HEL cells.
Platelet-associated antibody to glycoprotein IIb/IIIa from chronic immune thrombocytopenic purpura patients often binds to divalent cation- dependent antigens
Authors: Fujisawa K , Tani P , McMillan R 
Published: October 2019

Abstract
Chronic immune thrombocytopenic purpura (ITP) is a syndrome of destructive thrombocytopenia due to autoantibodies against platelet- associated antigens. These antigens are most commonly located on the platelet glycoprotein (GP) IIb/IIIa complex. In the present studies, we show that many platelet-associated anti-GPIIb/IIIa autoantibodies from chronic ITP patients depend on conformationally intact GPIIb/IIIa for maximal binding. We studied anti-GPIIb/IIIa autoantibodies from 19 ITP patients (15 platelet-associated, 8 plasma) and alloantibodies from three patients with posttransfusion purpura (anti-PIA1). Antibodies were preincubated with purified intact GPIIb/IIIa, EDTA-dissociated GPIIb/IIIa, GPIIIa, or GPIIb for 2 hours and then residual antibody was measured in an antigen capture assay. The binding results were compared with those obtained using antibody preincubated in buffer. Of the 15 platelet-associated autoantibodies studied, the intact GPIIb/IIIa complex resulted in greater inhibition of antibody binding than the EDTA-dissociated complex, with a mean inhibition ratio (intact/dissociated) of 7.9 (range, 1.4 to 30.3). Little inhibition was noted using either GPIIb or GPIIIa. Conversely, plasma anti-PIA1 alloantibodies or plasma autoantibodies from ITP patients against the c- terminal region of GPIIIa were more efficiently inhibited by the dissociated complex or purified GPIIIa. We conclude that platelet- associated anti-GPIIb/IIIa autoantibodies in chronic ITP are frequently directed to cation-dependent conformational antigens.
Human CD4 lymphocytes specifically recognize a peptide representing the fusion region of the hybrid protein pml/RAR alpha present in acute promyelocytic leukemia cells
Authors: Gambacorti-Passerini C , Grignani F , Arienti F , Pandolfi PP , Pelicci PG , Parmiani G 
Published: October 2019

Abstract
Fusion proteins present in leukemic cells frequently contain a new amino acid at the fusion point. We tested whether a peptide (BCR1/25) encompassing the fusion region of the hybrid molecule pml/RAR alpha, which is selectively expressed by acute promyelocytic leukemia (APL) cells, can be recognized by human T lymphocytes in vitro. CD4+ lymphocytes, at both polyclonal and clonal level, recognized peptide BCR1/25 in an HLA-DR--restricted fashion on presentation by autologous antigen-presenting cell (APC) or by APC expressing the HLA-DR11 restricting molecule. Control peptides corresponding to the normal pml and RAR alpha proteins were not recognized. One clone (DEG5) also exerted a high and specific cytotoxicity against autologous cells pulsed with BCR1/25. The autologous DE LCL containing a transduced pml/RAR alpha fusion gene and expressing a bcr1 type of the pml/RAR alpha hybrid protein induced the proliferation of DE anti-BCR1/25 T cell clones. It is concluded that the bcr1 type-pml/RAR alpha fusion protein of APL contains an antigenic site, absent from the normal parent molecules and recognized by human CD4+ lymphocytes.
Inactivation of interleukin-8 by the C5a-inactivating protease from serosal fluid
Authors: Ayesh SK , Azar Y , Babior BM , Matzner Y 
Published: October 2019

Abstract
The complement fragment C5a and the cytokine interleukin-8 (IL-8) are proinflammatory peptides with potent chemotactic activity toward neutrophils. We have previously shown that C5a can be inactivated by a protease that is found in normal synovial and peritoneal fluids but is absent from serosal fluids obtained from patients with familial Mediterranean fever (FMF). We report here that serosal fluids can also eliminate the chemotactic activity of IL-8. The agent responsible for IL-8 elimination appears to be the C5a-inactivating protease, because the pure protease can inactivate IL-8, inactivation of IL-8 by normal peritoneal fluid is partly prevented by an antibody raised against the purified C5a-inactivating protease, and IL-8 is not inactivated by peritoneal fluids from patients with FMF. The ability of this protease to inactivate both, early (C5a) and late (IL-8) inflammatory mediators identifies it as a potentially significant regulator of inflammation.
Tyrosine phosphorylation of guanosine triphosphatase activating protein by activation via surface IgG in human B cells
Authors: Yagura H , Oyaizu N , Pahwa S 
Published: October 2019

Abstract
In this study, we analyzed tyrosine phosphorylation of guanosine triphosphatase (GTPase) activating protein in human B cells stimulated through surface IgG, using Western blot and immunoprecipitation. Stimulation through surface IgG induced the tyrosine phosphorylation of GTPase-activating protein (GAP) and two associated proteins, a 190-Kd protein and a 62-Kd protein, within 1 minute and in a dose-dependent manner. This tyrosine phosphorylation was blocked by Genistein (Extrasynthese, Genay, France). These data suggest that GTPase- activating protein is involved in a signal transduction pathway initiated from surface IgG in human B cells.
Only the HLA class I gene minimal promoter elements are required for transactivation by human cytomegalovirus immediate early genes
Authors: Burns LJ , Waring JF , Reuter JJ , Stinski MF , Ginder GD 
Published: October 2019

Abstract
The immediate early (IE) genes of human cytomegalovirus (HCMV) are expressed in lymphocytes and are known to transactivate both viral and cellular promoters. The mechanism by which IE gene products of HCMV transactivate expression of the HLA A2 gene promoter in Jurkat cells, a T-lymphocyte cell line, was investigated. Transient expression assays were performed using plasmids containing the HLA A2 promoter-regulatory region linked to the bacterial chloramphenicol acetyltransferase (CAT) gene and a plasmid expressing the CMV IE genes. The upregulation of the HLA A2 promoter by HCVM IE gene products was shown not to be secondary to either interferon-gamma or -alpha. Previously described MHC class I regulatory or enhancer elements such as the interferon-stimulated response element (ISRE), NF-kappa B and H2TF1 binding sequences, and the interferon consensus sequence (ICS) were not required for transactivation of the A2 promoter. Rather, the only known regulatory elements in the HLA A2 promoter necessary for both basal expression and transactivation by HCVM IE gene products are the CCAAT box and TATA box motifs. These results support a model in which HCVM IE gene products act through the minimal HLA A2 promoter elements to increase gene expression.
Erythropoietin synthesis by tumor cells in a case of meningioma associated with erythrocytosis
Authors: Bruneval P , Sassy C , Mayeux P , Belair MF , Casadevall N , Roux FX , Varet B , Lacombe C 
Published: October 2019

Abstract
While secondary erythrocytosis is often associated with tumors arising from the kidney, other tumors have been described to originate in the liver, uterus, ovary, adrenal gland, and central nervous system, among which cerebellar hemangioblastomas are involved in most instances. Two cases of meningioma associated with erythrocytosis have already been reported. We observed a 59-year-old female patient who had developed a frontal meningioma associated with erythrocytosis. Before surgery, she had a significantly elevated total red blood cell volume with a normal plasma volume. Serum erythropoietin (Epo) dosage assessed by radioimmunoassay was within the normal range. The tumor was removed and the pathologic study found a meningotheliomatous meningioma. Total RNA from the tumor was hybridized to a monkey cDNA Epo probe. A strong 1.6- kb messenger RNA (mRNA) signal was observed, which is the expected size of human Epo mRNA. In situ hybridization with the 35S-labeled Epo probe was performed on frozen tumor tissue sections. A significant hybridization was observed in all the tumor cells, whereas the stroma was negative. Therefore, in this meningioma associated with erythrocytosis, Epo was produced by the tumor cells themselves.