bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Iron Chelator L1 Potentiates Oxidative DNA Damage in Iron-Loaded Liver Cells
Authors: Cragg Louise , Hebbel Robert P. , Miller Wesley , Solovey Alex , Selby Scott , Enright Helen 
Published: October 2019

Abstract
Iron-mediated carcinogenesis is thought to occur through the generation of oxygen radicals. Iron chelators are used in attempts to prevent the long term consequences of iron overload. In particular, 1,2-dimethyl-3-hydroxypyrid-4-one (L1), has shown promise as an effective chelator. Using an established hepatocellular model of iron overload, we studied the generation of iron-catalyzed oxidative DNA damage and the influence of iron chelators, including L1, on such damage. Iron loading of HepG2 cells was found to greatly exacerbate hydrogen peroxide–mediated DNA damage. Desferrithiocin was protective against iron/hydrogen peroxide–induced DNA damage; deferoxamine had no effect. In contrast, L1 exposure markedly potentiated hydrogen peroxide–mediated oxidative DNA damage in iron-loaded liver cells. However, when exposure to L1 was maintained during incubation with hydrogen peroxide, L1 exerted a protective effect. We interpret this as indicating that L1's potential toxicity is highly dependent on the L1:iron ratio. In vitro studies examining iron-mediated ascorbate oxidation in the presence of L1 showed that an L1:iron ratio must be at least 3 to 1 for L1 to inhibit the generation of free radicals; at lower concentrations of L1 increased oxygen radical generation occurs. In the clinical setting, such potentiation of iron-catalyzed oxidative DNA damage at low L1:iron ratios may lead to long-term toxicities that might preclude administration of L1 as an iron chelator. Whether this implication in fact extends to the in vivo situation will have to be verified in animal studies.
Role of Class-II Major Histocompatibility Complex (MHC)-Antigen–Positive Donor Leukocytes in Transfusion-Induced Alloimmunization to Donor Class-I MHC Antigens
Authors: Kao K.J. , del Rosario M.L.U. 
Published: October 2019

Abstract
It has been shown that peripheral-blood mononuclear leukocytes (MNL) are responsible for transfusion-induced alloimmunization to donor major histocompatability complex (MHC) antigens. However, it is not known which subset of MNL is responsible for this immune response. Because elimination of class-II MHC antigen-positive passenger leukocytes effectively prolongs the survival of allografts, it has been hypothesized that class-II positive MNL are responsible for immunizing transfusion recipients to donor MHC antigens. To test this hypothesis, two different approaches were used. First, we compared the alloantigenicity of BALB/c mice (H-2d) peripheral blood MNL before and after depletion of class-II positive cells. CBA mice (H-2k) were used as transfusion recipients. Antibody development to donor class-I H-2 antigens was determined by flow cytometry and enzyme-linked immunoassay. After four weekly transfusions of MNL depleted for class-II positive cells, only 25% of recipient mice developed antibodies to donor H-2d antigens. In contrast, all mice transfused with control MNL became immunized. Second, we studied the alloantigenicity of peripheral MNL from C57BL/6 mice (H-2b) with homozygous deficiency of class-II MHC molecules in H-2 disparate recipient mice. After transfusions with class-II MHC molecule-deficient MNL, 0% of BALB/c, 40% of C57BR, and 25% of CBA-recipient mice developed antibodies to donor H-2b antigen. All control recipient mice were immunized. The antibody activities of the controls were also higher than those in the treatment group who became immunized. Thus, our study shows that class-II MHC antigen-positive MNL play a significant role in transfusion-induced alloimmunization to donor class-I MHC antigens. The results also support the hypothesis that direct antigen presentation by donor class-II positive MNL to the immune system of transfusion recipients is critical for the initiation of humoral immune response to donor MHC antigens.
Presence of a p53 Gene Deletion in Patients With Multiple Myeloma Predicts for Short Survival After Conventional-Dose Chemotherapy
Authors: Drach Johannes , Ackermann Jutta , Fritz Elke , Krömer Elisabeth , Schuster Rudolf , Gisslinger Heinz , DeSantis Maria , Zojer Niklas , Fiegl Michael , Roka Sebastian , Schuster Judith , Heinz Renate , Ludwig Heinz , Huber Heinz 
Published: October 2019

Abstract
In multiple myeloma (MM), previous studies showed that mutations of the p53 gene are rare events in patients with newly diagnosed disease, but it is not known whether deletions of p53 are of any significance in MM. To address this question, we used interphase fluorescence in situ hybridization (FISH) with a DNA probe specific for the p53 locus at 17p13 and investigated bone marrow plasma cells from 72 patients with MM (59 patients = 81.9% before therapy). By FISH, deletions of p53, which were found to be predominantly monoallelic, were detected in 32.8% and 54.5% of patients with newly diagnosed and relapsed MM, respectively. Karyotypes from six of the patients with a p53 deletion by FISH showed a structural abnormality of 17p in only one of them. Additional FISH studies including a distal-17p probe (specific for theD17S34 locus) provided evidence for an interstitial deletion on 17p resulting in loss of p53 hybridization signals in myeloma cells. Among all 59 patients with newly diagnosed MM, presence of a p53 deletion was associated with stage III (P = .054), but not with other laboratory and clinical parameters. Patients with a p53 deletion had significantly shorter survival time compared with those without a deletion, both from the time of diagnosis (median 13.9v 38.7 months; P &lt; .0001) and from the time of initiation of induction treatment consisting of conventional dose chemotherapy (median 15.9 months v median not reached at 38 months; P &lt; .0002). On stepwise multivariate regression analysis, presence of a p53 deletion was the most significant independent parameter predicting for shortened survival (P = .002). We conclude that a p53 gene deletion, which can be identified by interphase FISH in almost a third of patients with newly diagnosed MM, is a novel prognostic factor predicting for short survival of MM patients treated with conventional-dose chemotherapy.
© 1998 by The American Society of Hematology.
Role of Adhesion Molecules in the Homing and Mobilization of Murine Hematopoietic Stem and Progenitor Cells
Authors: Vermeulen Monica , Le Pesteur Françoise , Gagnerault Marie-Claude , Mary Jean-Yves , Sainteny Françoise , Lepault Françoise 
Published: October 2019

AbstractBone marrow (BM) transplantation still must overcome multiple difficulties and should benefit from better understanding of stem-cell homing and mobilization. Here, we analyzed the involvement of several adhesion molecules in the two processes by treating mice with monoclonal antibodies against these molecules. Treatment of lethally irradiated mice grafted with isogeneic BM cells showed that at least two migration pathways are important for stem-cell homing to the BM, whereas only one of them is involved in lodging of colony-forming unit–spleen (CFU-S) in the spleen. We confirm that the VLA-4/VCAM-1 adhesion pathway is important for stem-cell homing to the BM only and show that CD44 is involved in CFU-S lodging in both BM and spleen. These results show that entry of CFU-S into the spleen is regulated. The observation that when one migration pathway is altered, CFU-S do not enter the BM via the other pathway may indicate that the two mechanisms involved in CFU-S homing into the BM are linked. The adhesion molecules VLA-4 and CD44 are also implied in the mobilization of stem cells into the blood stream of mice injected once with anti–VLA-4 or anti-CD44. Anti–VLA-4 administration led to a significant increase in circulating stem cells as early as 8 hours after treatment. Stem cells mobilized by anti–VLA-4 comprise cells with high self-renewal potential and thus may be used for long-term reconstitution of the hematopoietic tissue.© 1998 by The American Society of Hematology.
Synergistic Activation of MAP Kinase (ERK1/2) by Erythropoietin and Stem Cell Factor Is Essential for Expanded Erythropoiesis
Authors: Sui Xingwei , Krantz Sanford B. , You Min , Zhao Zhizhuang 
Published: October 2019

AbstractStem cell factor (SCF) and erythropoietin (EPO) work synergistically to support erythropoiesis, but the mechanism for this synergism is unknown. By using purified human erythroid colony-forming cells (ECFC), we have found that SCF and EPO synergistically activate MAP kinase (MAPK, ERK1/2), which correlates with the cell growth and thus may be responsible for the synergistic effects. Treatment of the cells with PD98059 and wortmannin, inhibitors of MEK and PI-3 kinase, respectively, inhibited the synergistic activation of MAPK and also the cell growth, further supporting this conclusion. Wortmannin only inhibits MAPK activation induced by EPO but not that by SCF, suggesting that SCF and EPO may activate MAPK through different pathways, which would facilitate synergy. Furthermore, EPO, but not SCF, led to activation of STAT5, whereas SCF and wortmannin had no effect on the EPO-induced STAT5 activation, suggesting that STAT5 is not involved in the synergistic action of SCF and EPO. Together, the data suggest that synergistic activation of MAPK by SCF and EPO is essential for expanded erythropoiesis.© 1998 by The American Society of Hematology.
Impaired Activation of NFκB in T Cells From a Subset of Renal Cell Carcinoma Patients Is Mediated by Inhibition of Phosphorylation and Degradation of the Inhibitor, IκB
Authors: Ling Weijun , Rayman Patricia , Uzzo Robert , Clark Peter , Kim Hyung Jin , Tubbs Raymond , Novick Andrew , Bukowski Ronald , Hamilton Thomas , Finke James 
Published: October 2019

AbstractActivation of the transcription factor NFκB in peripheral blood T cells from patients with renal cell carcinoma (RCC) is compromised. This impaired signaling function results from a failure of RelA and c-Rel to translocate to the nucleus though normal levels of Rel proteins are present in the cytoplasm. We demonstrate here in a subset of RCC patients that the defect in NFκB activation is attributable to the absence of phosphorylation and degradation of the inhibitor IκB. In patient T cells there was no stimulus dependent decrease in the cytoplasmic level of IκB. Coimmunoprecipitation studies showed that RelA was in complex with IκB and was not released after stimulation. Moreover, the phosphorylated form of IκB detected in normal T cells after activation is absent in patient T cells. Additional experiments showed that soluble products from RCCs (RCC-S) can reproduce the same phenotype in T cells from healthy individuals. Supernatant fluid from cultured explants of RCC, but not normal kidney, inhibited the stimulus dependent nuclear translocation of NFκB without altering the cytoplasmic levels of RelA, c-Rel, and NFκB1. Phosphorylation and degradation of IκB was also blocked by RCC-S. The mechanistic similarities between patient-derived T cells and normal T cells cultured with RCC-S suggest that the tumor-derived products may be the primary mediators of impaired T-cell function in this tumor system.© 1998 by The American Society of Hematology.
Tissue Inhibitor of Metalloproteinase (TIMP)-1 Induces Differentiation and an Antiapoptotic Phenotype in Germinal Center B Cells
Authors: Guedez Liliana , Courtemanch Laurel , Stetler-Stevenson Maryalice 
Published: October 2019

AbstractTissue inhibitors of metalloproteinases (TIMPs) have been shown to be multifunctional factors. Contrasting with their enzyme-inhibitory activity, TIMPs also promote cell growth. Previously, we have reported an enhanced expression of TIMP-1 by normal reactive B cells and high-grade lymphomas. In the present study, a series of Burkitt’s lymphoma (BL) cell lines were analyzed for their expression of TIMP-1. TIMP-1 expression correlates with upregulation of activation and survival markers. TIMP-1–negative cells express the phenotype associated with group I BL lines and Epstein-Barr virus (EBV)-negative, nonendemic BLs (CD10+, CD38+, sIg+, and CD77+). However, TIMP-1+ BL lines showed group II/III BL phenotype, downregulation of the above markers, and upregulation and secretion of the activation marker CD23. Also, TIMP-1+ cells have high levels of CD40 expression. To determine whether TIMP-1 is directly involved in the BL phenotype, an EBV-negative BL line JD38 was infected with timp-1–expressing retrovirus and analyzed. In the absence of EBV, upregulation of TIMP-1 is sufficient to induce the same phenotype seen in TIMP-1+, EBV+ BL lines (CD10−, CD38−, sIg−, CD77−, CD23+, CD40 bright). This study not only suggests a role for TIMP-1 in BLs, but also supports its value as a prognostic factor.This is a US government work. There are no restrictions on its use.
The Chimeric E2A-HLF Transcription Factor Abrogates p53-Induced Apoptosis in Myeloid Leukemia Cells
Authors: Altura Rachel A. , Inukai Takeshi , Ashmun Richard A. , Zambetti Gerard P. , Roussel Martine F. , Look A. Thomas 
Published: October 2019

Abstract
Leukemic lymphoblasts expressing the E2A-HLF oncoprotein possess wild-type p53 genes, but do not undergo apoptosis in response to DNA damage. Experimentally, E2A-HLF prevents apoptosis due to growth factor deprivation or γ-irradiation in interleukin-3 (IL-3)–dependent murine pro-B cells. To directly test the chimeric protein’s ability to abrogate p53-mediated cell death, we used mouse myeloid leukemia cells (M1p53tsval) that constitutively express a temperature-sensitive (ts) mutant p53 gene and undergo apoptosis when p53 assumes an active wild-type configuration. This effect is blocked by treatment with IL-6, which allows the cells to survive in culture despite wild-type p53 activation. We introduced E2A-HLF into M1p53tsval cells and found that they were resistant to p53-mediated apoptosis and that E2A-HLF effectively substituted for the survival functions of IL-6. The expression of p53-responsive genes such as p21 and Bax was upregulated normally, suggesting that E2A-HLF acts downstream of p53 to block execution of the p53-induced apoptotic program. NFIL3, a growth factor-regulated bZIP protein that binds to the same DNA-consensus site as E2A-HLF, delays apoptosis in IL-3–dependent pro-B cells deprived of growth factor. By contrast, in the present study, enforced expression of NFIL3 failed to protect M1p53tsval cells from p53-dependent apoptosis and actively antagonized the ability of IL-6 to rescue cells from that fate, consistent with its role as either a transcriptional repressor or activator, depending on the cell type in which it is expressed. We conclude that the E2A-HLF chimera abrogates p53-induced apoptosis in leukemic cells, possibly through the transcriptional modulation of cell death pathways that are activated by p53 in response to DNA damage.
© 1998 by The American Society of Hematology.
Infusion of Cytotoxic T Cells for the Prevention and Treatment of Epstein-Barr Virus–Induced Lymphoma in Allogeneic Transplant Recipients
Authors: Rooney Cliona M. , Smith Colton A. , Ng Catherine Y.C. , Loftin Susan K. , Sixbey John W. , Gan Yanjun , Srivastava Deo-Kumar , Bowman Laura C. , Krance Robert A. , Brenner Malcolm K. , Heslop Helen E. 
Published: October 2019

Abstract
Epstein-Barr virus (EBV) causes potentially lethal immunoblastic lymphoma in up to 25% of children receiving bone marrow transplants from unrelated or HLA-mismatched donors. Because this complication appears to stem from a deficiency of EBV-specific cytotoxic T cells, we assessed the safety and efficacy of donor-derived polyclonal (CD4+ and CD8+) T-cell lines as immunoprophylaxis and treatment for EBV-related lymphoma. Thirty-nine patients considered to be at high risk for EBV-induced lymphoma each received 2 to 4 intravenous infusions of donor-derived EBV-specific T lymphocytes, after they had received T-cell–depleted bone marrow from HLA-matched unrelated donors (n = 33) or mismatched family members (n = 6). The immunologic effects of this therapy were monitored during and after the infusions. Infused cells were identified by detection of the neo marker gene. EBV-specific T cells bearing theneo marker were identified in all but 1 of the patients. Serial analysis of DNA detected the marker gene for as long as 18 weeks in unmanipulated peripheral blood mononuclear cells and for as long as 38 months in regenerated lines of EBV-specific cytotoxic T cells. Six patients (15.5%) had greatly increased amounts of EBV-DNA on study entry (&gt;2,000 genome copies/106 mononuclear cells), indicating uncontrolled EBV replication, a complication that has had a high correlation with subsequent development of overt lymphoma. All of these patients showed 2 to 4 log decreases in viral DNA levels within 2 to 3 weeks after infusion and none developed lymphoma, confirming the antiviral activity of the donor-derived cells. There were no toxic effects that could be attributed to prophylactic T-cell therapy. Two additional patients who did not receive prophylaxis and developed overt immunoblastic lymphoma responded fully to T-cell infusion. Polyclonal donor-derived T-cell lines specific for EBV proteins can thus be used safely to prevent EBV-related immunoblastic lymphoma after allogeneic marrow transplantation and may also be effective in the treatment of established disease.
© 1998 by The American Society of Hematology.
Retroviral Marking of Canine Bone Marrow: Long-Term, High-Level Expression of Human Interleukin-2 Receptor Common Gamma Chain in Canine Lymphocytes
Authors: Whitwam Todd , Haskins Mark E. , Henthorn Paula S. , Kraszewski Jennifer N. , Kleiman Sandra E. , Seidel Nancy E. , Bodine David M. , Puck Jennifer M. 
Published: October 2019

AbstractOptimization of retroviral gene transfer into hematopoietic cells of the dog will facilitate gene therapy of canine X-linked severe combined immunodeficiency (XSCID) and in turn advance similar efforts to treat human XSCID. Both canine and human XSCID are caused by defects in the common γ chain, γc, of receptors for interleukin-2 and other cytokines. In this study, normal dogs were given retrovirally transduced bone marrow cells with and without preharvest mobilization by the canine growth factors granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF). Harvey sarcoma virus and Moloney murine leukemia virus constructs were used, both containing cDNA encoding human γc. The Harvey-based vector transduced into cytokine-primed marrow yielded persistent detectable provirus in bone marrow and blood and expression of human γc on peripheral lymphocytes. In three dogs, human γc expression disappeared after 19 to 34 weeks but reappeared and was sustained, in one dog beyond 16 months posttransplantation, upon immunosuppression with cyclosporin A and prednisone, with up to 25% of lymphocytes expressing human γc. The long-term expression of human γc in a high proportion of normal canine lymphocytes predicts that retrovirus-mediated gene correction of hematopoietic cells may prove to be of clinical benefit in humans affected with this XSCID.This is a US government work. There are no restrictions on its use.
Phosphorothioate Oligonucleotides Inhibit the Intrinsic Tenase Complex
Authors: Sheehan John P. , Lan Hao-Chang 
Published: October 2019

AbstractSystemic administration of ISIS 2302, a 20-mer antisense phosphorothioate oligonucleotide targeting human intercellular adhesion molecule-1 mRNA, causes prolongation of plasma clotting times in both monkey and human studies. The anticoagulant effects of ISIS 2302 were investigated with both in vitro coagulation assays in human plasma and purified enzyme systems. At high oligonucleotide plasma concentrations (&gt;100 μg/mL), prolongation of the prothrombin and thrombin times was observed. In a thrombin time assay using purified components, high concentrations of ISIS 2302 inhibited thrombin clotting activity both by stimulating inhibition by heparin cofactor II and directly competing with fibrinogen for binding to anion binding exosite I. In contrast, low concentrations of ISIS 2302 (&lt;100 μg/mL) showed a selective, linear prolongation of the activated partial thromboplastin time (PTT). The rate limiting effect of 50 μg/mL ISIS 2302, which prolonged the PTT to 1.5 times control, was identified by sequential modification of the clotting assay. Delaying addition of oligonucleotide until after contact activation failed to correct prolongation of the PTT. The calcium-dependent steps of the intrinsic pathway were individually assessed by adding sufficient activated coagulation factor to correct the PTT in plasma deficient in that specific factor. Addition of factor XIa, IXa, VIIIa, or Va failed to correct the PTT in the presence of ISIS 2302. In contrast, 0.2 nmol/L factor Xa corrected prolongation of the PTT in factor X–deficient plasma with or without oligonucleotide present. ISIS 2302 (50 μg/mL) did not prolong a modified Russel viper venom time, suggesting no significant inhibition of prothrombinase. Thus, 50 μg/mL ISIS 2302 prolonged the PTT by selectively inhibiting intrinsic tenase activity. ISIS 2302 showed partial inhibition of intrinsic tenase activity (to approximately 35% of control) at clinically relevant oligonucleotide concentrations in a chromogenic assay. This activity was oligonucleotide sequence–independent but required the phosphorothioate backbone, suggesting that inhibition of intrinsic tenase is a general property of this class of oligonucleotides. These results are relevant to both the therapeutic use of phosphorothioate oligonucleotides and the potential design of inhibitors of the intrinsic tenase complex, a novel target for anticoagulation.© 1998 by The American Society of Hematology.
Antiphospholipid Antibodies Accelerate Plasma Coagulation by Inhibiting Annexin-V Binding to Phospholipids: A “Lupus Procoagulant” Phenomenon
Authors: Rand Jacob H. , Wu Xiao-Xuan , Andree Harry A.M. , Ross J.B. Alexander , Rusinova Elena , Gascon-Lema Mayra G. , Calandri Cesare , Harpel Peter C. 
Published: October 2019

AbstractThe antiphospholipid syndrome is a thrombophilic condition marked by antibodies that recognize anionic phospholipid-protein cofactor complexes. We recently reported that exposure to IgG fractions from antiphospholipid patients reduces the level of annexin-V, a phospholipid-binding anticoagulant protein, on cultured trophoblasts and endothelial cells and accelerates coagulation of plasma exposed to these cells. Therefore, we asked whether antiphospholipid antibodies might directly reduce annexin-V binding to noncellular phospholipid substrates. Using ellipsometry, we found that antiphospholipid IgGs reduce the quantity of annexin-V bound to phospholipid bilayers; this reduction is dependent on the presence of β2-glycoprotein I. Also, exposure to plasmas containing antiphospholipid antibodies reduces annexin-V binding to phosphatidyl serine-coated microtiter plates, frozen thawed washed platelets, activated partial thromboplastin time (aPTT) reagent and prothrombin time reagent and reduces the anticoagulant effect of the protein. These studies show that antiphospholipid antibodies interfere with the binding of annexin-V to anionic phospholipid and with its anticoagulant activity. This acceleration of coagulation, due to reduced binding of annexin V, stands in marked contrast to the “lupus anticoagulant effect” previously described in these patients. These results are the first direct demonstration of the displacement of annexin-V and the consequent acceleration of coagulation on noncellular phospholipid surfaces by antiphospholipid antibodies.© 1998 by The American Society of Hematology.