bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impaired in vitro growth of purified (CD34+) hematopoietic progenitors in human immunodeficiency virus-1 seropositive thrombocytopenic individuals
Authors: Zauli G , Re MC , Davis B , Sen L , Visani G , Gugliotta L , Furlini G , La Placa M 
Published: October 2019

Abstract
In this report the role played by human immunodeficiency virus type-1 (HIV-1) in the pathogenesis of HIV-1-related thrombocytopenia was investigated. CD34+ hematopoietic stem/progenitor cells were purified from the bone marrow (BM) of HIV-1(+) thrombocytopenic patients, HIV- 1(+) nonthrombocytopenic individuals, HIV-1(-) patients with immune thrombocytopenic purpura, and HIV-1(-) normal donors. CD34+ cells from HIV-1(+) thrombocytopenic individuals alone showed a reduced capacity to give rise to megakaryocytic colonies (CFU-Meg) and also a progressive and significant decline in cell number when placed in liquid culture containing recombinant human interleukin-3 (rIL-3). This decline involved not only megakaryocyte but also erythroid and granulocyte/macrophage progenitors. The defects in megakaryocyte colony formation and CD34+ cell growth did not result from a productive HIV-1 infection of CD34+ cells. Moreover, HIV-1 DNA was absent from CD34+ cells in 10 of 12 thrombocytopenic patients examined. On the other hand, the decreased survival/proliferation of CD34+ cells in liquid culture, within the HIV-1(+) thrombocytopenic patients, was correlated with the presence of HIV-1 p24 antigen in BM plasma. These results demonstrate an impairment of CD34+ cells in HIV-1(+) individuals presenting thrombocytopenia as the only hematologic manifestation. Furthermore, these findings suggest that increased viral replication in the BM microenvironment may cause this impairment and possibly contributes to HIV-induced thrombocytopenia.
Reduction of tissue iron stores and normalization of serum ferritin during treatment with the oral iron chelator L1 in thalassemia intermedia
Authors: Olivieri NF , Koren G , Matsui D , Liu PP , Blendis L , Cameron R , McClelland RA , Templeton DM 
Published: October 2019

Abstract
In patients with thalassemia intermedia in whom hyperabsorption of iron may result in serious organ dysfunction, an orally effective iron- chelating drug would have major therapeutic advantages, especially for the many patients with thalassemia intermedia in the Third World. We report reduction in tissue iron stores and normalization of serum ferritin concentration after 9-month therapy with the oral chelator 1,2- dimethyl-3-hydroxypyrid-4-one (L1) in a 29-year-old man with thalassemia intermedia and clinically significant iron overload (SF 2,174 micrograms/L, transferrin saturation 100%; elevated AST and ALT, abnormal cardiac radionuclide angiogram) who was enrolled in the study with L1 75 mg/kg/day after he refused deferoxamine therapy. L1-Induced 24-hour urinary iron excretion during the first 6 months of therapy was (mean +/- SD, range) 53 +/- 30 (11 to 109) mg (0.77 mg/kg), declining during the last 3 months of L1 to 24 +/- 14 (13–40) mg (0.36 mg/kg), as serum ferritin decreased steadily to normal range (present value, 251 micrograms/L). Dramatic improvement in signal intensity of the liver and mild improvement in that of the heart was shown by comparison of T1- weighted spin echo magnetic resonance imaging with images obtained immediately before L1 administration was observed after 9 months of L1 therapy. Hepatic iron concentration decreased from 14.6 mg/g dry weight of liver before L1 therapy to 1.9 mg/g liver after 9 months of therapy. This constitutes the first report of normalization of serum ferritin concentration in parallel with demonstrated reduction in tissue iron stores as a result of treatment with L1. Use of L1 as a therapeutic option in patients with thalassemia intermedia and iron overload appears warranted.
Onset of erythropoietin response in murine erythroid colony-forming units: assignment to early S-phase in a specific cell generation
Authors: Landschulz KT , Boyer SH , Noyes AN , Rogers OC , Frelin LP 
Published: October 2019

Abstract
Murine erythroid colony-forming units (CFU-E) representing successive cell generations in a six-generation long in vitro maturation sequence were tested for their response to erythropoietin (Epo) by measurement of Epo-exposure times necessary to stimulate heme biosynthesis. Generation I CFU-E, which produce mainly 32-cell erythroid colonies, were isolated in 82% average purity from spleens of thiamphenicol- treated anemic animals via differential centrifugation. Generation II CFU-E, which produce mainly 16-cell colonies, were similarly isolated in 51% average purity. Although both types of CFU-E had equivalent dose sensitivity to and affinity for Epo, generation II CFU-E responded to shorter pulses of Epo than did generation I. Correlations between DNA cell-cycle profiles and 59Fe-heme biosynthesis resulting from pulsed exposures established that appreciable Epo response only begins when CFU-E attain early S-phase of generation II. Because CFU-E did not require Epo or other serum factors to pass from generation I to II and because the onset of Epo responsiveness coincided with the beginning of DNA replication in generation II, we suppose that differentiation has reprogrammed one or more of the events associated with generation II S- phase in CFU-E and that these alterations allow Epo to act. Further comparisons between CFU-E from generation I and II may allow us to identify the alterations in question and the nature of their interaction with Epo.
Acetylcholinesterase in murine erythroleukemia (Friend) cells: evidence for megakaryocyte-like expression and potential growth-regulatory role of enzyme activity
Authors: Paoletti F , Mocali A , Vannucchi AM 
Published: October 2019

Abstract
Features of true acetylcholinesterase (AChE) regulation during growth and differentiation of Friend murine erythroleukemia cells (MELC) have been investigated with respect to other erythroid and nonerythroid murine elements. Enzyme levels of uninduced MELC were in between the very low AChE contents of erythroid cells and the huge amounts of activity exhibited by megakaryocytes and platelets. After MELC commitment to terminal division, the enzyme-specific activity increased largely, approaching values that were much closer to those of thrombocytic than of normal erythroid elements. The bulk of AChE activity in MELC, megakaryocytes, and platelets was found to be located in the cytosol as a free-soluble form. Moreover, during incubation, MELC actively released large amounts of AChE into the medium, like it occurs in murine thrombocytes. Conversely, the enzyme of the erythroid elements was mainly associated with the membranes and was not released extracellularly. Experiments with inducers showed that changes in AChE- specific activity of MELC correlated directly with the arrest of cell proliferation rather than with the activation of differentiated erythroid functions. The inverse relationship existing between MELC growth rates and AChE levels was further supported by the relative enzyme activities of the slow- and fast-growing subclones. We conclude that uninduced MELC potentially share properties of both the erythroid and megakaryoblastic phenotype. The latter might be revealed by typical regulation of AChE activity according to a thrombocytic-like program activated upon MELC commitment to terminal division. Eventually, the inhibition of MELC growth by exogenous pure bovine AChE suggested that the secreted murine enzyme might serve as a potential negative signal of cellular replication.
Characterization of urokinase receptor expression by human placental trophoblasts
Authors: Zini JM , Murray SC , Graham CH , Lala PK , Kariko K , Barnathan ES , Mazar A , Henkin J , Cines DB , McCrae KR 
Published: October 2019

Abstract
The processes of implantation and placentation are both dependent on the invasion and remodeling of the uterine endometrium and vasculature by trophoblasts. Because the secretion and autocrine binding of urokinase (uPA) appears to be a common mechanism used by cells to facilitate plasmin-dependent tissue invasion, we measured the production of uPA and expression of uPA receptors by trophoblasts. Prourokinase bound specifically, reversibly, and with high affinity to cultured trophoblasts, via the uPA epidermal growth factor-like domain. Trophoblasts derived from two first-trimester placentae bound more prourokinase than cells isolated from term placentae. Furthermore, in vitro differentiation of cultured cytotrophoblasts into syncytiotrophoblasts was associated with diminished expression of urokinase receptors and a parallel decrease in the cellular content of uPA receptor mRNA. Trophoblasts also secreted prourokinase and plasminogen activator inhibitors types 1 and 2 (PAI-1 and PAI-2). Although prourokinase was secreted in amounts sufficient to endogenously saturate trophoblast uPA receptors, trophoblasts secreted greater amounts of PAI-1 and PAI-2 than uPA, and no net plasminogen activator activity was detected in trophoblast conditioned medium. In contrast, plasminogen added directly to cultured trophoblasts was readily converted to plasmin. Although the invasion and remodeling of uterine tissues by trophoblasts is a complex process dependent on several proteases of varying specificity, our findings suggest that the expression and modulation of urokinase receptors on the trophoblast cell surface may play an important role in this process.
Origin of anti-idiotypic activity against anti-factor VIII autoantibodies in pools of normal human immunoglobulin G (IVIg)
Authors: Dietrich G , Algiman M , Sultan Y , Nydegger UE , Kazatchkine MD 
Published: October 2019

Abstract
Therapeutic preparations of polyspecific IgG obtained from plasma pools of a large number of normal donors (IVIg) express anti-idiotypic activity against a wide spectrum of natural and disease-associated autoantibodies. The present study investigated the origin of anti- idiotypic activity against autoantibodies to factor VIII. The neutralizing activity of pools of IgG against patients' anti-factor VIII autoantibodies was not influenced by the presence of individuals with natural anti-factor VIII antibodies among donors contributing to the pool. A higher frequency of neutralizing antibodies against anti- factor VIII autoantibodies was found in aged donors as compared with young adults and in pools of IgG from multiparous women as compared with IgG from random donors. Pooling IgG from several donors synergistically enhanced the inhibitory activity of the pools. Thus, a neutralizing activity against anti-factor VIII autoantibodies was detected in pools of IgG of as few as two to four donors of whom individually tested IgG did not exhibit inhibitory activity against anti-factor VIII autoantibodies. These observations suggest that aged donors and multiparous women may be privileged sources for the anti- idiotypic activity of IVIg against autoantibodies and emphasize that the expression of anti-idiotypic activity in IVIg results from a synergistic participation of anti-idiotypes from each donor contributing to the pool.
Regulation of complement functional efficiency by histidine-rich glycoprotein
Authors: Chang NS , Leu RW , Rummage JA , Anderson JK , Mole JE 
Published: October 2019

Abstract
The modulation of complement functional efficiency by serum histidine- rich glycoprotein (HRG) was investigated. Addition of exogenous HRG to prewarmed diluted serum, followed immediately by sensitized sheep erythrocytes (EA), resulted in enhanced hemolysis. However, when HRG was incubated with diluted serum for 10 minutes at 37 degrees C, inhibition of hemolysis occurred. The biphasic modulation of complement function was also obtained with the complement alternative pathway when HRG was added to diluted serum for hemolysis of rabbit erythrocytes. Partial reduction of complement functional activity was shown when serum was absorbed by an HRG-Sepharose 6MB column. Western blot analysis showed that complement C8, C9, factor D, and S-protein in diluted serum were bound by nylon membrane-immobilized HRG. However, by immunoprecipitation of relatively undiluted serum with anti-HRG IgG beads, HRG was found to coprecipitate with S-protein and plasminogen, which suggested that HRG may complex with these proteins in serum. In functional tests, HRG inhibited C8 hemolytic activity, probably by preventing C8 binding to EAC1–7 cells. HRG also enhanced polymerization of purified C9 as well as the generation of a 45-Kd C9 fragment. Such an effect was even more pronounced in the presence of divalent cations with the reaction mixtures of C9 and HRG. Partial dimerization of C9 was shown when exogenous HRG was added to normal serum. In contrast, polymerization of serum C9 was inhibited by exogenous HRG during poly I:C activation of serum or incubation under low ionic strength conditions. HRG was further shown to inhibit factor D-mediated cleavage of factor B when bound by cobra venom factor. The molecular basis by which HRG regulates serum complement function is not clear. Hypothetically, the tandem repetitions of a consensus histidine-rich penta-peptide sequence in HRG may provide a highly charged area that interacts with complement components.
The translocation (6;9) (p23;q34) shows consistent rearrangement of two genes and defines a myeloproliferative disorder with specific clinical features
Authors: Soekarman D , von Lindern M , Daenen S , de Jong B , Fonatsch C , Heinze B , Bartram C , Hagemeijer A , Grosveld G 
Published: October 2019

Abstract
Translocation (6;9)(p23;q34) is a cytogenetic aberration that can be found in specific subtypes of both acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). This translocation is associated with an unfavourable prognosis. Recently, the genes involved in the t(6;9) were isolated and characterized. Breakpoints in both the dek gene on chromosome 6 and the can gene on chromosome 9 appear to occur in defined regions, which allows us to diagnose this type of leukemia at the molecular level. Moreover, because of the translocation a chimeric dek-can mRNA is formed which, as we show here, is an additional target for diagnosis via cDNA-preparation and the polymerase chain reaction (PCR). We studied 17 patients whose blood cells and/or bone marrow cells showed a t(6;9) with karyotypic analysis. Fourteen patients suffered from AML, one patient had a refractory anemia with excess of blasts in transformation (RAEBt), one patient had an acute myelofibrosis (AMF), and one patient a chronic myeloid leukemia (CML). In nine cases studies at the DNA and RNA levels were possible while in seven cases only the DNA could be analyzed. In one case only RNA was available. Conventional Southern blot analysis showed the presence of rearrangements of both the dek gene and the can gene. In both genes, breakpoints cluster in one intron in the patients investigated. The presence of a consistent chimeric dek-can product after cDNA preparation followed by the PCR was demonstrated. We conclude from our data that the t(6;9) is found in myeloproliferative disorders with typical clinical characteristics. This translocation results in highly consistent abnormalities at the molecular level.
Complement activation during storage of blood under normal blood bank conditions. Effects of proteinase inhibitors and leukocyte depletion
Authors: Schleuning M , Schmid-Haslbeck M , Utz H , Jochum M , Heim M , Mempel W , Wilmanns W 
Published: October 2019

Abstract
During storage of CPD-A1 preserved whole blood factors of the complement cascade become activated, as evidenced by a rapid increase in the concentrations of C3a-desArg and C4a-desArg. After 10 to 14 days of whole blood storage, the elevations of C3a and C4a levels were highly significant. This increase was paralleled by an increase in the concentration of the lysosomal proteinase elastase from polymorphonuclear (PMN) granulocytes. By contrast, the concentration of the C3 activator complex C4b2b remained unchanged even after 3 weeks of storage. The supplementation of the anticoagulant CPD-A1 with the polyvalent-proteinase-inhibitor aprotinin and the specific elastase- inhibitor eglin C failed to inhibit complement activation, whereas leukocyte depletion could partially abolish the increase of the concentration of C4a, but had no effect on C3a concentrations. These observations support the notion that cleavage of C4 during storage of whole blood is partially leukocyte dependent, whereas the activation of C3 is possibly caused by the activation of the alternate pathway of the complement system by contact of plasma with plastic surfaces.
Hemolysis of transfused group O red blood cells in minor ABO- incompatible unrelated-donor bone marrow transplants in patients receiving cyclosporine without posttransplant methotrexate
Authors: Gajewski JL , Petz LD , Calhoun L , O'Rourke S , Landaw EM , Lyddane NR , Hunt LA , Schiller GJ , Ho WG , Champlin RE 
Published: October 2019

Abstract
Hemolysis most commonly occurs following bone marrow transplant when there is “minor” ABO blood group incompatibility between donor and recipient. The hemolysis has been attributed to destruction of the patient's incompatible erythrocytes by donor-derived anti-A and/or anti- B antibody produced from “passenger” immunocompetent donor lymphocytes. Extraordinary transfusion requirements of group O erythrocytes in a series of patients receiving unrelated minor ABO-incompatible marrow grafts led us to investigate whether this mechanism could account for the extent of hemolysis observed. In seven consecutive minor ABO- incompatible unrelated-donor bone marrow transplant recipients receiving cyclosporine without posttransplant methotrexate, we observed excessive hemolysis. For cases in this index group, a strongly reactive donor-derived ABO blood group antibody was identified coincident with development of hemolysis. Transfusion requirements in the first three patients (26 U of group O erythrocytes each) greatly exceeded the recipient's volume of incompatible erythrocytes, indicating that lysis of transfused group O erythrocytes was also occurring. Pretransplant erythrocyte exchange transfusion with group O erythrocytes performed in the four subsequent patients decreased the severity of hemolysis, but did not prevent it. Among minor ABO-incompatible marrow graft recipients, an analysis of variance demonstrated effects on transfusion requirements due to donor-recipient relationship being unrelated (P less than .002) and the use of posttransplant methotrexate (P = .0001), and there was interaction between these two factors (P less than .001). Bone marrow transplants from unrelated donors resulted in an exaggerated immune response to ABO blood group antigens, which was associated with hemolysis of transfused group O erythrocytes, as well as the patient's ABO-incompatible erythrocytes. This serious complication may be prevented by posttransplant immunosuppression with methotrexate.
Genetic and structural characterization of an amino acid dimorphism in glycoprotein Ib alpha involved in platelet transfusion refractoriness
Authors: Murata M , Furihata K , Ishida F , Russell SR , Ware J , Ruggeri ZM 
Published: October 2019

Abstract
The platelet-specific alloantigen, Siba, located within the alpha- subunit of the glycoprotein (GP) Ib-IX membrane receptor, has been found to be involved in the pathogenesis of platelet transfusion refractoriness. We have identified the existence of a naturally occurring threonine/methionine dimorphism at position 145 of the GPIb alpha sequence, and determined that the Siba antigen corresponds to the molecule containing methionine145. The diallelic codons can be detected by restriction enzyme analysis of amplified genomic DNA fragments from the GPIb alpha gene. Evaluation of 61 healthy blood donors showed that the allele frequencies are 89% and 11% for the threonine145 and methionine145 codons, respectively. A positive correlation exists between platelet reactivity with the anti-Siba antibody and the presence of a methionine145-encoding allele. Moreover, recombinant expression of two soluble GPIb alpha fragments differing only at residue 145, provided definitive evidence that the human anti-Siba antibody reacts only with the molecule containing methionine145. These results explain the structural basis of the Siba human alloantigen system and define screening methodologies useful in transfusion medicine to match donor and recipient platelets accordingly.
"Stem cell" origin of the hematopoietic defect in dyskeratosis congenita
Authors: Marsh JC , Will AJ , Hows JM , Sartori P , Darbyshire PJ , Williamson PJ , Oscier DG , Dexter TM , Testa NG 
Published: October 2019

Abstract
We have used the long-term bone marrow culture (LTBMC) system to analyze hematopoiesis in three patients with dyskeratosis congenita (DC), two of whom had aplastic anemia, and the third had a normal blood count (apart from mild macrocytosis) and normal BM cellularity. Hematopoiesis was severely defective in all three patients, as measured by a low incidence of colony-forming cells and a low level of hematopoiesis in LTBMC. The function of the marrow stroma was normal in its ability to support the growth of hematopoietic progenitors from normal marrows seeded onto them in all three cases, but the generation of hematopoietic progenitors from patients marrow cells inoculated onto normal stromas was reduced, thus suggesting the defect to be of stem cell origin. The parents and unaffected brother of one of the families have also been studied in LTBMC and all showed normal hematopoietic and stromal cell function. From this study we speculate that there are some similarities between DC and the defect in the W/Wv mouse.
Further phenotypic characterization and isolation of human hematopoietic progenitor cells using a monoclonal antibody to the c-kit receptor
Authors: Briddell RA , Broudy VC , Bruno E , Brandt JE , Srour EF , Hoffman R 
Published: October 2019

Abstract
A mouse antihuman monoclonal IgG2a antibody, termed stem cell receptor- 1 (SR-1), specific for a determinant of the c-kit ligand receptor (KR), was used as an immunologic probe to analyze KR expression by human bone marrow hematopoietic progenitor cells. Monoclonal antibodies to CD34 and HLA-DR were used in a multicolor staining protocol in conjunction with SR-1 to further define the phenotypes of various classes of hematopoietic progenitor cells. Expression of KR (SR-1+) on hematopoietic progenitor cells identified subpopulations of cells expressing CD34 (CD34+). While one-half of the CD34- and HLA-DR- expressing cells (CD34+ HLA-DR+) expressed the KR (SR-1+), one-third of the CD34+ cells that lacked HLA-DR expression (CD34+ HLA-DR-) were SR- 1+. The CD34+ HLA-DR+ SR-1+ cell population contained the vast majority of the more differentiated progenitor cells, including the colony- forming unit (CFU) granulocyte-macrophage; burst-forming unit- erythrocyte; CFU-granulocyte, erythrocyte, macrophage, megakaryocyte; and the CFU-megakaryocyte. The overall progenitor cell cloning efficiency of this subpopulation was greater than 31%. By contrast, the CD34+ HLA-DR- SR-1+ cell population contained fewer of these more differentiated progenitor cells but exclusively contained the more primitive progenitor cells, the BFU-megakaryocyte, high proliferative potential-colony-forming cell, and long-term bone marrow culture- initiating cell. The overall progenitor cell cloning efficiency of this subpopulation was greater than 7%. Both the CD34+ HLA-DR- and CD34+ HLA- DR+ cell subpopulations lacking KR expression contained few assayable hematopoietic progenitor cells. Long-term bone marrow cultures initiated with CD34+ HLA-DR- SR-1+ but not CD34+ HLA-DR- SR-1- cells, which were repeatedly supplemented with c-kit ligand (KL) and interleukin-3, generated assayable progenitor cells of at least 2 lineages for 10 weeks. These experiments demonstrate the expression of the KR throughout the hierarchy of human hematopoietic progenitor cell development. We conclude from our data that the KL and KR play a pivotal role in cytokine regulation of both the primitive and more differentiated human hematopoietic progenitor cells.