bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Gene Transfer Into Baboon Marrow Repopulating Cells Using Recombinant Human Fibronectin Fragment CH-296 in Combination With Interleukin-6, Stem Cell Factor, FLT-3 Ligand, and Megakaryocyte Growth and Development Factor
Authors: Kiem Hans-Peter , Andrews Robert G. , Morris Julia , Peterson Laura , Heyward Scott , Allen James M. , Rasko John E.J. , Potter Jennifer , Miller A. Dusty 
Published: October 2019

We have used a competitive repopulation assay in baboons to develop improved methods for hematopoietic stem cell transduction and have previously shown increased gene transfer into baboon marrow repopulating cells using a gibbon ape leukemia virus (GALV)-pseudotype retroviral vector (Kiem et al, Blood 90:4638, 1997). In this study using GALV-pseudotype vectors, we examined additional variables that have been reported to increase gene transfer into hematopoietic progenitor cells in culture for their ability to increase gene transfer into baboon hematopoietic repopulating cells. Baboon marrow was harvested after in vivo administration (priming) of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF). CD34-enriched marrow cells were divided into two equal fractions to directly compare transduction efficiencies under different gene transfer conditions. Transduction by either incubation with retroviral vectors on CH-296–coated flasks or by cocultivation on vector-producing cells was studied in five animals; in one animal, transduction on CH-296 was compared with transduction on bovine serum albumin (BSA)-coated flasks. The highest level of gene transfer was obtained after 24 hours of prestimulation followed by 48 hours of incubation on CH-296 in vector-containing medium in the presence of multiple hematopoietic growth factors (interleukin-6, stem cell factor, FLT-3 ligand, and megakaryocyte growth and development factor). Using these conditions, up to 20% of peripheral blood and marrow cells contained vector sequences for more than 20 weeks, as determined by both polymerase chain reaction and Southern blot analysis. Gene transfer rates were higher for cells transduced on CH-296 as compared with BSA or cocultivation. In one animal, we have used a vector expressing a cell surface protein (human placental alkaline phosphatase) and have detected 10% and 5% of peripheral blood cells expressing the transduced gene 2 and 4 weeks after transplantation as measured by flow cytometry. In conclusion, the conditions described here have resulted in gene transfer rates that will allow detection of transduced cells by flow cytometry to facilitate the evaluation of gene expression. The levels of gene transfer obtained with these conditions suggest the potential for therapeutic efficacy in diseases affecting the hematopoietic system.© 1998 by The American Society of Hematology.
Cytogenetic Abnormalities in Primary Myelodysplastic Syndrome Are Highly Predictive of Outcome After Allogeneic Bone Marrow Transplantation
Authors: Nevill Thomas J. , Fung Henry C. , Shepherd John D. , Horsman Douglas E. , Nantel Stephen H. , Klingemann Hans-G. , Forrest Donna L. , Toze Cynthia L. , Sutherland Heather J. , Hogge Donna E. , Naiman Sheldon C. , Le Alan , Brockington Daphne A. , Barnett Michael J. 
Published: October 2019

Allogeneic bone marrow transplantation (BMT) is the only curative therapy available for patients with myelodysplastic syndrome (MDS). In an attempt to identify prognostic factors influencing outcome, we collected data retrospectively on 60 consecutive adult patients who had undergone BMT at our center for primary MDS or acute myelogenous leukemia evolving from preexisting primary MDS (sAML). Patients were divided into subgroups according to cytogenetic abnormalities based on a recently described International MDS Workshop categorization system. The 7-year actuarial event-free survival (EFS), relapse rate, and nonrelapse mortality (NRM) for all patients were 29% (95% confidence interval [CI], 16% to 43%), 42% (CI, 24% to 67%), and 50% (CI, 37% to 64%), respectively. The EFS for the good-, intermediate-, and poor-risk cytogenetic subgroups were 51% (CI, 30% to 69%), 40% (CI, 16% to 63%), and 6% (CI, 0% to 24%), respectively (P= .003). The corresponding actuarial relapse rates were 19% (CI, 6% to 49%), 12% (CI, 2% to 61%), and 82% (CI, 48% to 99%), respectively (P = .002) with no difference in NRM between the subgroups. Univariate analysis showed cytogenetic category, French-American-British (FAB) subtype, and graft-versus-host disease (GVHD) prophylaxis used to be predictive of relapse and EFS. In multivariate analysis, only the cytogenetic category was predictive of EFS, with the relative risk of treatment failure for the good-, intermediate-, and poor-risk cytogenetic subgroups being 1.0, 1.5, and 3.5, respectively (P = .004). For adults with primary MDS and sAML, even after BMT, poor-risk cytogenetics are predictive of an unfavorable outcome; novel treatment strategies will be required to improve results with allogeneic BMT in this patient population.© 1998 by The American Society of Hematology.
An Agonist Murine Monoclonal Antibody to the Human c-Mpl Receptor Stimulates Megakaryocytopoiesis
Authors: Deng Bijia , Banu Naheed , Malloy Beth , Hass Philip , Wang Jian Feng , Cavacini Lisa , Eaton Dan , Avraham Hava 
Published: October 2019

Thrombopoietin (TPO) is a hematopoietic growth factor that stimulates megakaryocytopoiesis and platelet production in vivo and promotes the development of identifiable megakaryocytes in vitro. We have developed a murine monoclonal antibody, BAH-1, raised against human megakaryocytic cells, which specifically recognizes the c-Mpl receptor and shows agonist activity by stimulating megakaryocytopoiesis in vitro. BAH-1 antibody specifically binds to platelets and to recombinant c-Mpl with high affinity. Similar to TPO, BAH-1 alone supported the formation of colony-forming unit-megakaryocyte (CFU-MK) colonies. The combination of BAH-1 plus interleukin-3 or of BAH-1 plus human TPO significantly increased the number of human CFU-MK colonies. In addition, BAH-1 monoclonal antibody stimulated the proliferation and maturation of primary bone marrow megakaryocytes in a dynamic heterogeneous liquid culture system. Individual large megakaryocytes as well as small megakaryocytic cells were observed in cultures of CD34+ CD41+cells in the presence of BAH-1 antibodies. Similar to TPO, BAH-1 antibody induced a significant response of murine immature megakaryocytes as observed by an increase in the detectable numbers of acetylcholinesterase-positive megakaryocytes. No effects of BAH-1 antibody were observed on colony-forming unit–granulocyte-macrophage, burst-forming unit-erythroid, or colony-forming unit-erythroid colonies. In vivo studies showed that BAH-1, alone or in combination with TPO, expands the numbers of megakaryocytic progenitor cells in myelosuppressed mice. This antibody should prove useful in understanding the structure-function aspects of the c-Mpl receptor as well as in evaluating the effects of the sustained activation of this receptor in preclinical models of severe thrombocytopenia.
© 1998 by The American Society of Hematology.
No Effect of Clot Age or Thrombolysis on Argatroban’s Inhibition of Thrombin
Authors: Hantgan Roy R. , Jerome W. Gray , Hursting Marcie J. 
Published: October 2019

The purpose of this study was to establish the effects of clot age and thrombolysis, with either streptokinase or tissue-type plasminogen activator (tPA), on argatroban’s ability to inhibit thrombin. The antithrombotic activity of argatroban has been quantified in fibrin clot permeation and fibrin clot perfusion systems as a function of clot age and composition. Analysis of the argatroban dose-response data with a competitive inhibition model has yielded IC50 values in the low micromolar range. Results obtained in a plasma clot permeation system have also shown that argatroban is a potent inhibitor of clot-bound thrombin, independent of either clot age or the presence of hemostatically active platelets. Treatment of aged plasma clots with either streptokinase or alteplase, at therapeutic levels, increased the available thrombin activity, yet argatroban still inhibited this clot-associated thrombin with IC50 values in the low micromolar range. Scanning electron microscopy/morphometric analyses demonstrated that permeation with argatroban had no significant effects on clot structure. We conclude that argatroban is an effective inhibitor of thrombin bound to aged fibrin clots, in purified systems and in plasma clots, as well as in clots that have been treated with the thrombolytic agents streptokinase and alteplase.© 1998 by The American Society of Hematology.
Integrins Involved in the Adhesion of Megakaryocytes to Fibronectin and Fibrinogen
Authors: Schick P.K. , Wojenski C.M. , He X. , Walker J. , Marcinkiewicz C. , Niewiarowski S. 
Published: October 2019

We studied integrins involved in the adhesion of resting and activated megakaryocytes (MK) to fibronectin (FN) and fibrinogen (FGN). Guinea pig MK were isolated and in some experiments were activated by thrombin. MK adhering to FN or FGN coated on coverslips were quantitated by a computerized image analysis program. The binding of soluble human FN to MK was detected by Western blotting. Anti-integrin antibodies, disintegrins, and cyclic RGD peptides were used to identify integrins involved in the adhesion of MK to FN or FGN. Resting MK adhered to coverslips with immobilized FN. The adhesion of MK to FN was primarily inhibited by an anti-5 antibody and EMF-10, a distintegrin highly specific for 5β1. However, the adhesion of MK to FN was not blocked by agents that inhibit ΙΙbβ3, vβ3 or 4β1. A β1 activating antibody increased the number of MK bound to FN due to the activation of 5β1. The binding of soluble FN was also primarily inhibited by agents that block 5β1. Resting MK did not adhere to FGN. However, MK activated by thrombin did adhere to FGN. This binding was mediated by ΙΙbβ3, because binding was inhibited by bitistatin, a disintegrin, and a cyclic RGD peptide that are known to block this integrin. The binding of thrombin-activated MK to FN was mediated by both 5β1 and ΙΙbβ3 based on the additive effect of agents that inhibit these integrins. The study indicates that resting MK bind to FN but not to FGN and that 5β1 is the major integrin involved in the binding of MK to FN. Activated MK bind to FGN primarily by IIbβ3. However, the binding of activated MK to FN is due to both 5β1 and IIbβ3. The demonstration that 5β1 and that IIbβ3 are involved in MK adhesion indicates that these integrins may have a role in MK maturation and platelet production.© 1998 by The American Society of Hematology.
Molecular and Serological Examination of the Relationship of Human Herpesvirus 8 to Multiple Myeloma: orf 26 Sequences in Bone Marrow Stroma Are Not Restricted to Myeloma Patients and Other Regions of the Genome Are Not Detected
Authors: Tisdale John F. , Stewart A. Keith , Dickstein Bruce , Little Richard F. , Dubé Ian , Cappe D. , Dunbar Cynthia E. , Brown Kevin E. 
Published: October 2019

Human herpesvirus 8 (HHV-8) genomic sequences were recently detected by polymerase chain reaction (PCR) and in situ hybridization in bone marrow stromal cells grown from multiple myeloma (MM) patients, but not in cells from control subjects (Rettig et al, Science 276:1851, 1997). We sought to confirm these observations in our own group of MM patients (n = 30). DNA was extracted from adherent stromal cells grown under varying conditions and assayed for HHV-8 sequence using PCR to amplify the orf 26 (KS330) sequence (Chang et al,Science 266:1865, 1997), as initially reported. Samples from human control subjects (n = 25) were concurrently extracted and analyzed. After 30 cycles of amplification, we did not detect any positive samples. In a more sensitive nested PCR, samples from 18 of 30 (60%) MM patients were positive, at about the limit of detection, but orf 26 sequence was also amplified from 11 of 25 (44%) human control samples. However, PCR amplification from other regions of the viral genome (orf 72 and orf 75) was uniformly negative for all MM and control samples, despite equivalent sensitivity. Additionally, all sera from MM patients were negative for HHV-8 IgG by immunofluorescence. Our data do not support a role of HHV-8 in the etiology of MM but may suggest the presence of a related (KS330-containing) virus in MM patients and in some control subjects.This is a US government work. There are no restrictions on its use.
Polymorphisms of Platelet Membrane Glycoprotein Ib Associated With Arterial Thrombotic Disease
Authors: Gonzalez-Conejero Rocio , Lozano Maria L. , Rivera Jose , Corral Javier , Iniesta Juan A. , Moraleda Jose M. , Vicente Vicente 
Published: October 2019

Platelet membrane glycoprotein Ib (GPIb) is a major receptor for von Willebrand factor and thrombin, which plays a key role in the initial development of thrombi. Two polymorphisms (HPA-2 and VNTR) that affect phenotype have been described in GPIb. The relevance of these polymorphisms to thrombotic disease was investigated by genotypic identification in three case-control studies: 104 case patients with acute cerebrovascular disease (CVD), 101 case patients with acute coronary heart disease (CHD), 95 patients with deep venous thrombosis (DVT), and one control age-, sex-, and race-matched for each case patient. Results show that the C/B genotype of the VNTR and the HPA-2b polymorphisms of GPIb are strongly associated with increased risk of coronary heart disease and cerebral vascular disease but not with deep vein thrombosis. These two polymorphisms of GPIb may represent newly identified risk factors for arterial thrombotic disease, but not for venous thrombosis.© 1998 by The American Society of Hematology.
A Regulatory Role for Fcγ Receptors CD16 and CD32 in the Development of Murine B Cells
Authors: de Andres Belen , Mueller Allan L. , Verbeek Sjef , Sandor Matyas , Lynch Richard G. 
Published: October 2019

Early in development, murine B-lineage progenitor cells express two classes of IgG Fc receptors (FcγR) designated as FcγRII (CD32) and FcγRIII (CD16), but mature B lymphocytes only express FcγRII (CD32), which functions as an inhibitor of B-cell activation when it is induced to associate with mIgM. The functions of CD16 and CD32 on B-lineage precursor cells have not previously been investigated. To search for FcγR functions on developing B-lineage cells, normal murine bone marrow cells were cultured in the presence of 2.4G2, a rat monoclonal antibody that binds to CD16 and CD32, or in the presence of control normal rat IgG, and then the B-lineage compartment was analyzed for effects. Cultures that contained 2.4G2 showed enhanced growth and differentiation of B-lineage cells compared with control cultures. The enhancing effect of 2.4G2 also occurred when fluorescence-activated cell-sorted B-cell precursors (B220+, sIgM−, HSAhigh, FcγR+) from normal bone marrow were cocultured with BMS2, a bone marrow stromal cell line, but not when they were cultured in BMS2-conditioned media. The enhancement of B-lineage development induced by 2.4G2 was CD16-dependent and CD32-dependent, because 2.4G2 did not effect B-lineage growth or differentiation in cultures of bone marrow from mice in which either the gene encoding CD16 or CD32 had been disrupted. Analysis of fresh bone marrow from the CD16 gene-disrupted mice showed normal numbers and distribution of cells within the B-cell compartment, but in CD32 gene-disrupted mice, the B-cell compartment was significantly enlarged. These experiments provide several lines of evidence that the FcγR expressed on murine B-cell precursors can influence their growth and differentiation.© 1998 by The American Society of Hematology.
DNA Fiber Fluorescence In Situ Hybridization Analysis of Immunoglobulin Class Switching in B-Cell Neoplasia: Aberrant CH Gene Rearrangements in Follicle Center-Cell Lymphoma
Authors: Vaandrager Jan-Willem , Schuuring Ed , Kluin-Nelemans Hanneke C. , Dyer Martin J.S. , Raap Anton K. , Kluin Philip M. 
Published: October 2019

Immunoglobulin class switching usually involves deletion of part of the immunoglobulin CH region. By DNA fiber fluorescence in situ hybridization (FISH) with a barcode of probes covering the DH, JH, and CH genes, the configuration of the entire CH region can be visualized on single DNA molecules. Using this technique, we have studied class switching in three types of B-cell neoplasia, mantle-cell lymphoma (MCL), follicular lymphoma (FL) and hairy cell leukemia (HCL), representing B cells in, respectively, pregerminal center, germinal center, and postgerminal center stages of development. In MCL and FL, simultaneous detection of the t(11;14) and t(14;18) breakpoint with probes for the BCL-1 and BCL-2 loci, respectively, allowed differentiation between productive and nonproductive alleles. In none of 10 MCL cases was class switching detected. In 21 HCL, all nonimmunoglobulin M (IgM) cases had class-switch deletion consistent with the expressed isotype on at least one allele. In FL, however, a peculiar pattern of CH rearrangement was observed. In IgM expressing FL, the translocated alleles had switched in 11 of 13 cases, and the nontranslocated allele showed complex rearrangements downstream from the Cμ-Cδ genes in 9 of 13 cases. These downstream rearrangements may reflect tumor-specific deregulation of the class-switch machinery. All seven immunoglobulin G (IgG) expressing FL showed class switching on both alleles. Fiber FISH analysis also showed several polymorphisms. The most frequent one, present on 38% of all analyzed alleles, consisted of an extra Cγ gene or pseudogene in the 3′ cluster.© 1998 by The American Society of Hematology.
The Relationship of the −5, −8, and −24 Variant Alleles in African Americans to Triosephosphate Isomerase (TPI) Enzyme Activity and to TPI Deficiency
Authors: Schneider Arthur , Forman Linda , Westwood Beryl , Yim Catherine , Lin James , Singh Satinder , Beutler Ernest 
Published: October 2019

In 424 African-American and 75 white subjects, we found that the −5 (TPI 592 A→G), −8 (TPI 589 G→A), and −24 (TPI 573 T→G) variants in the triosephosphate isomerase (TPI) gene occurred frequently (41.0%) in the African-American subjects but did not occur in the whites. These data suggest that this set of polymorphisms may turn out to be one of the higher-incidence molecular markers of African lineage, a surprising finding because others had reported that these nucleotide substitutions were restricted to a small subset of African Americans who had been characterized as TPI-deficiency heterozygotes. Additionally, we investigated the relationship of these variants to TPI-enzyme activity. Although the variant substitutions (occurring in three haplotypes: −5 alone, −5 −8, and −5 −8 −24) were associated with moderate reduction in enzyme activity, severe-deficiency heterozygotes could not be identified with certainty, and none of the haplotypes were restricted to subjects with marked reduction of enzyme activity. Three subjects were homozygous for the −5 −8 haplotype, a finding inconsistent with the putative role of this haplotype as the cause of a null variant incompatible with life in homozygotes. Despite these findings, the possibility remains that the −5 −8 or −5 −8 −24 haplotypes may in some instances contribute to compound heterozygosity and clinical TPI deficiency.© 1998 by The American Society of Hematology.
Genetic influences on F cells and other hematologic variables: a twin heritability study
Authors: Garner C. , Tatu T. , Reittie J. E. , Littlewood T. , Darley J. , Cervino S. , Farrall M. , Kelly P. , Spector T. D. , Thein S. L. 
Published: October 2019

To assess the relative contribution of genetic factors in the variation of F cells (FC) and other hematologic variables, we conducted a classical twin study in unselected twins. The sample included 264 identical (monozygotic [MZ]) twin pairs and 511 nonidentical (dizygotic [DZ]) same-sex twin pairs (aged 20 to 80 years) from the St. Thomas' UK Adult Twin Register. The FC values were distributed continuously and positively skewed, with values ranging from 0.6% to 22%. FC values were higher in women than in men and decreased with age, with the variables accounting for 2% of the total FC variance. The intraclass correlations of FC values were higher in MZ (rMZ = 0.89) than in DZ (rDZ = 0.49) twins. The XmnI-Gγ polymorphism in the β-globin gene cluster had a significant effect on FC levels, accounting for approximately 13% of the total FC variance. Variance components analysis showed that the FC values were accounted for predominantly by additive genetic and nonshared environmental influences, with an estimate of heritability of 0.89. Hemoglobin levels and red blood cell, white blood cell, and platelet numbers were also substantially heritable, with heritability estimates of 0.37, 0.42, 0.62, and 0.57, respectively.
Previously, studies of sib pairs with sickle cell disease and isolated family studies showed that high levels of Hb F and FC tend to be inherited. Here, our classical twin study demonstrated that the variance of FC levels in healthy adults is largely genetically determined. (Blood. 2000;95:342-346)
Single-tube multiplex-PCR screen for common deletional determinants of α-thalassemia
Authors: Chong Samuel S. , Boehm Corinne D. , Higgs Douglas R. , Cutting Garry R. 
Published: October 2019

Abstract
-Thalassemia is very common throughout all tropical and subtropical regions of the world. In Southeast Asia and the Mediterranean regions, compound heterozygotes and homozygotes may have anemia that is mild to severe (hemoglobin [Hb] H disease) or lethal (Hb Bart's hydrops fetalis). We have developed a reliable, single-tube multiplex–polymerase chain reaction (PCR) assay for the 6 most frequently observed determinants of -thalassemia. The assay allows simple, high throughput genetic screening for these common hematological disorders. (Blood. 2000;95:360-362)
The C-class chemokine, lymphotactin, impairs the induction of Th1-type lymphokines in human CD4+ T cells
Authors: Cerdan Chantal , Serfling Edgar , Olive Daniel 
Published: October 2019

AbstractChemokines are involved in the regulation of leukocyte migration and for some of them, T-cell costimulation. To date, the only direct property of lymphotactin (Lptn), the unique member of the C class of chemokines, consists of T-cell chemoattraction. This report describes a novel function for Lptn in human T-lymphocyte biology, by demonstrating the direct ability of Lptn to both inhibit and costimulate CD4+ and CD8+ T-cell activation, respectively. Lptn but not RANTES inhibited CD4+ T-cell proliferation, through a decreased production of Th1 (interleukin [IL]-2, interferon [IFN]-γ) but not Th2 (IL-4, IL-13) lymphokines, and decreased IL-2R expression. Transfections in Jurkat cells showed a Lptn-mediated transcriptional down-regulation of gene-promoter activities specific for Th1-type lymphokines, as well as of nuclear factor of activated T cells (NF-AT) but not AP-1 or NF-ΚB enhancer activities. This suppressive action of Lptn could be compensated by overexpression of NF-ATc but not NF-ATp. CD4+ T-cell proliferation was completely restored by exogenous IL-2 or reversed by pertussis toxin, wortmannin, and genistein, suggesting the involvement of multiple partners in Lptn signaling. In contrast to CD4+ cells, Lptn exerted a potent costimulatory activity on CD8+ T-cell proliferation and IL-2 secretion. These data provide important insights into the role of Lptn in differential regulation of normal human T-cell activation and its possible implication in immune response disorders.