bluuebunny/crossref_metadata_2025_split huggingface dataset:
Specificity of autoantibodies in autoimmune thrombocytopenia
Authors: van Leeuwen EF , van der Ven JT , Engelfriet CP , von dem Borne AE 
Published: October 2019

Abstract
In 42 patients with autoimmune thrombocytopenia (AITP) and a positive direct platelet suspension immunofluorescence test (PSIFT), the antigenic specificity of the autoantibodies was studied. Because the autoantibodies were often not detectable in the serum and additional HLA antibodies may disturb the reaction pattern with the platelet panel, we used eluates prepared from the patients' platelets for this study. Thirty-five patients had antibodies equally reactive with normal platelets, irrespective of their antigenic make-up, but not with the platelets from two Glanzmann's disease patients. Absorption and elution experiments in two patients showed that his was probably not due to the presence of a combination of anti-Zwa and anti-Zwb antibodies. Thus, the majority of autoantibodies against platelets seems to be directed against antigenic determinants not present on Glanzmann's disease platelets, but perhaps located on the platelet-membrane glycoproteins IIb and/or IIIa. In ten patients, antibodies of no, or still unknown, specificity were detected. Three of these had additional antibodies not reactive with the platelets of the two Glanzmann patients.
Cyclic neutropenia (CN): a clue to the control of granulopoiesis
Authors: von Schulthess GK , Mazer NA 
Published: October 2019

Abstract
A simple quantitative feedback model of granulopoiesis is presented and discussed within the framework of existing data on granulopoiesis in both normals and patients with cyclic neutropenia (CN). The model assumes that the controlled compartment is the bone marrow pool of mature neutrophils (PMNs), which sends a negative feedback signal to the mitotic pool of early granulocyte precursors (i.e., CFU-C, myeloblasts, etc.) thus controlling the granulocyte production rate. Three parameters are found to play important roles in determining the response of the system to perturbations. These are: TM, the granulocyte maturation time; a, a parameter reflecting the strength of the negative feedback exerted by mature PMNs on the granulocyte production rate; and b, a parameter describing the leakiness of the bone marrow for PMN egress. It is shown that depending on the relative magnitudes of a and b, the system will either respond to perturbations with a damped oscillation (a less than b: the normal state) or with a sustained oscillation (a greater than b: the CN state). In both cases, the oscillation period is found to approximately equal 2TM. Deductions of the values of a, b, and TM from experimental data are consistent with the predictions of the model and show an increased value of a in CN relative to the normal state. This suggests an overly active feedback mechanism as the pathophysiologic basis of CN. In addition, the model can explain how various therapeutic agent correct CN and also provides insight into why other hematologic cell lines and CSA oscillate in CN.
Serologic profile of alphamethyldopa-induced hemolytic anemia: correlation between cell-bound IgM and hemolysis
Authors: Lalezari P , Louie JE , Fadlallah N 
Published: October 2019

Abstract
Erythrocyte-bound immunoglobulins have been characterized by a PVP- potentiated antiglobulin test in 11 patients who had developed antibodies after treatment with alpha-methyldopa. Serologic profiles were recognized that could distinguish between the hemolyzing and nonhemolyzing patients: IgM antibodies together with the first component of complement (C1q) were demonstrated on erythrocytes of all eight hemolyzing patients. By contrast, these immunoproteins were absent from the cells of nonhemolyzing patients and became undetectable when the hemolyzing patients recovered. IgG and its subclasses were variably present on erythrocytes of all patients regardless of hemolytic activity. Eluates prepared from erythrocytes of the hemolyzing patients were shown to contain both IgG and IgM, and fixes C1q, C3, and C4. Eluates from the nonhemolyzing patients contained only IgG. The IgM antibodies differed from the commonly occurring cold agglutinins in that they were warm-reactive and were mainly concentrated on the patients' cells rather than being free in the serum. Because of their nonagglutinating property, it is suggested that they are monomeric IgM. It is concluded that the high affinity, warm- reactive IgM and not the IgG antibodies are primarily responsible for clinically manifest anemia in patients receiving alphamethyldopa and that the hemolytic activity is probably mediated by the classic pathway of complement activation.
Properties of sulfatides in factor-XII-dependent contact activation
Authors: Tans G , Griffin JH 
Published: October 2019

Abstract
Incubation of normal human plasma with low amounts of sulfatides resulted in the initiation of intrinsic coagulation and the appearance of kallikrein activity. The optimal initiation of procoagulant and kallikrein amidolytic activity was dependent on the presence of factor XII, high molecular weight kininogen, and prekallikrein. Since the activated partial thromboplastin clotting times in prekallikrein- deficient plasma approach normal values upon prolonged incubation with kaolin, this phenomenon of autocorrection was studied and found to be even more pronounced in the presence of sulfatides. Autocorrection was essentially completed in 5 min in the presence of sulfatides, whereas a preincubation of 15–20 min was required in the presence of kaolin. The limited proteolysis of 125I-factor XII in plasma during incubation with activating material or during clotting was determined. Cleavage of factor XII was more rapid and more extensive in the presence of sulfatides than in the presence of kaolin. In prekallikrein-deficient plasma, factor XII cleavage was completed within 5 min in the presence of sulfatides and within 15 min in the presence of kaolin. Thus, the appearance of factor-XII-dependent coagulant activity correlates with the limited proteolysis of factor XII when normal or prekallikrein- deficient plasma is activated by sulfatides or kaolin.
Isolation and structural characterization of the polypeptide subunits of membrane glycoprotein IIb-IIIa from human platelets
Authors: McEver RP , Baenziger JU , Majerus PW 
Published: October 2019

Abstract
We have previously demonstrated the isolation of platelet membrane glycoprotein IIb-IIIa by affinity chromatography with a specific monoclonal antibody. We have now separated the polypeptide subunits IIb and IIIa of the isolated glycoprotein by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis and have compared their structural features. Both IIb and IIIa contain approximately 15% carbohydrate, but IIIa contains a larger percentage of mannose residues, suggesting the presence of high mannose as well as complex N- linked oligosaccharide chains. The amino acid compositions are sufficiently similar to imply areas of sequence homology between the two subunits. To examine further the relationship between the subunits, we digested a mixture of 125I-IIb and 131I-IIIa with trypsin and then separated the radiolabeled peptides by high performance liquid chromatography. The resultant peptide maps of IIb and IIIa are completely different. This indicates that neither subunit is derived from the other and suggests that polypeptides IIb and IIIa are products of separate genes.
A liquid culture system for murine megakaryocyte progenitor cells
Authors: Nagasawa T , Nakazawa M , Abe T 
Published: October 2019

Abstract
A liquid culture system is described for murine megakaryocyte progenitor cells (CFU-M) in the presence of pokeweed-mitogen-stimulated spleen-cell conditioned medium. There were dose-related responses between the number of CFU-M developed and the number of cells cultured and the dosage of conditioned medium in this liquid culture system. Murine CFU-M were abundantly cloned in this system an the plating efficiency was similar in comparison with that in a plasma clot system. The acetylcholinesterase-positive colonies (more than 4 acetylcholinesterase-positive cells) were clearly seen on day 3 of culture, and they reached a maximum (60.5 +/- 10.7/2 x 10(5) cells) on day 7 of culture. Ultrastructural analyses of megakaryocytic maturation in this system showed that a few megakaryocytes produced platelets that were released in the culture medium on day 5 of culture. This liquid culture system is suitable for the study of the dynamic process of the megakaryocyte-platelet system.
Mechanism of dexamethasone inhibition of chemotactic factor induced granulocyte aggregation
Authors: Oseas RS , Allen J , Yang HH , Baehner RL , Boxer LA 
Published: October 2019

Abstract
The reaction of FMLP with granulocytes causes aggregation and degranulation and enhances adherence to endothelium. To evaluate whether prevention of granule extrusion could impair these granulocyte activities, granulocytes were treated with either dexamethasone or hydrocortisone prior to treatment with FMLP. Dexamethasone was added to suspensions of cytochalasin B-treated granulocytes; it markedly impaired the aggregation response of the granulocytes of FMLP. When cytochalasin-B was not used, granulocyte aggregation in response to FMLP or PMA was inhibited by dexamethasone. Although dexamethasone prevented aggregation of cells following stimulation with FMLP or PMA, it failed to prevent the aggregation of granulocytes induced by rabbit lactoferrin. Adherence of granulocytes to human endothelial monolayers was enhanced by FMLP; dexamethasone inhibited the enhancement. However, with the addition of human lactoferrin to the granulocytes exposed to dexamethasone, the cells were able to adhere as well to endothelium as the cells exposed to FMLP but free of dexamethasone. When cytochalasin- B-treated granulocytes were incubated with dexamethasone or hydrocortisone prior to the addition of FMLP, the subsequent release of lactoferrin was substantially blocked, whereas the release of the primary granule products, lysozyme and beta-glucuronidase, was attenuated but not completely blocked. Thus, corticosteroids might block chemotactic-factor-induced granulocyte aggregation by selectively preventing release of specific granule products that contribute to and sustain aggregation.
Human leukemia cell line K562 responds to erythroid-potentiating activity
Authors: Gauwerky CE , Lusis AJ , Golde DW 
Published: October 2019

Abstract
We report that erythroid-potentiating activity (EPA), known to stimulate the proliferation of normal human erythroid precursors in vitro, has a growth-promoting effect on human K562 erythroleukemia cells and Friend mouse erythroleukemia cells. Detailed studies were carried out using an EPA produced by a human T-lymphoblast line (Mo). Although EPA has not been purified to homogeneity, several observations indicate that the factor elaborated by Mo cells that stimulates erythroleukemia cell growth is the EPA molecule. The erythroleukemia growth factor cofractionates with EPA using gel exclusion chromatography, isoelectric focusing, and ion exchange chromatography. In addition, the activities exhibit similar kinetics of heat inactivation. A granulocyte-macrophage colony-stimulating factor also elaborated by Mo cells had no effect on the growth of the erythroleukemia cells. Other sources of EPA, such as peripheral blood leukocyte-conditioned medium, preparations from urine of anemic patients, and medium conditioned by a human monocyte-like cell line, stimulated erythroleukemia cell growth. Mouse sources of EPA (termed “burst-promoting activity”) stimulated mouse but not human erythroleukemia cells. The availability of cell lines apparently responsive to EPA should prove useful for examining the mode of action of this regulator of erythropoiesis.
Enrichment for CFU-C from murine and human bone marrow using soybean agglutinin
Authors: Reisner Y , Kapoor N , Hodes MZ , O'Reilly RJ , Good RA 
Published: October 2019

Abstract
Mouse bone marrow and spleen cells agglutinated by soybean agglutinin (SBA) or peanut agglutinin (PNA) were previously shown to be enriched for spleen colony-forming cells (CFU-S) and sufficiently depleted of graft-versus-host reaction producing cells to allow hematologic reconstitution of lethally irradiated allogeneic recipient mice. A similar enrichment for cells capable of forming colonies in soft agar culture (CFU-C) has now been found in the SBA-agglutinated fraction of mouse bone marrow cells, in contrast to the finding that in human bone marrow the majority of the CFU-C are in the fraction not agglutinated by SBA. Cytofluorometric studies with fluorescein-labeled SBA (FITC- SBA) revealed that the majority of both mouse and human bone marrow cells bind the lectin. Experiments mixing the human marrow fractions separated by SBA reveal that true enrichment for CFU-C is achieved in the unagglutinated fraction, as opposed to a possible depletion of a suppressor cell population. Granulocytic, monocytic, and mixed cell colonies were all enriched in the SBA-unagglutinated cell fraction from human bone marrow.
Dexamethasone synergistically induces chemotactic peptide receptor expression in HL-60 cells
Authors: Skubitz KM , Zhen YS , August JT 
Published: October 2019

Abstract
We have examined the effect of physiologic concentrations of dexamethasone on the induction of differentiation of the human promyelocytic leukemia cells (HL-60) and the activity of surface receptors for the f-met-leu-phe chemotactic peptide. Dexamethasone at a concentration of 500 nM was markedly synergistic with dimethylformamide and dimethylsulfoxide, but not with trans-retinoic acid, in inducing f- met-leu-phe binding by HL-60 cells. The increase in peptide binding was due to an increase in the activity of peptide receptors rather than an increase in receptor affinity. The effect of dexamethasone was relatively specific for peptide binding as there was little effect when HL-60 differentiation was assessed by cell morphology or the ability of the cells to reduce nitroblue tetrazolium. Dexamethasone alone had no reproducible effect on HL-60 differentiation as assessed by the three criteria tested. The dexamethasone concentration required for half maximal synergism correlated with the known binding constant of the hormone for steroid receptors in HL-60 cells but the effect of dexamethasone was not blocked with the steroid blocking agents 17 alpha methyltestosterone or progesterone.
The effect of folate analogues and vitamin B12 on provision of thymine nucleotides for DNA synthesis in megaloblastic anemia
Authors: Taheri MR , Wickremasinghe RG , Jackson BF , Hoffbrand AV 
Published: October 2019

Abstract
The role of vitamin B12 in the folate dependent biosynthesis of thymidine nucleotides is controversial. In an attempt to clarify this, three methods have been used to assess the relative efficacy of vitamin B12 (hydroxocobalamin) and various folate analogues in titrated concentrations at correcting ‘de novo’ thymidylate synthesis by megaloblastic human marrow cells: (1) The deoxyuridine (dU) suppression test which analyses the reduction in (3H)-thymidine labeling of DNA by unlabeled dU. Marrow cells were also labeled with (6–3H)-dU with assessment of (2) its incorporation into DNA and (3) the accumulation of (6–3H)-deoxyuridine monophosphate (3H-dUMP). The three methods gave similar results. In both, N6-formyl tetrahydrofolate (formyl-FH4) was the most effective agent at correcting thymidylate synthesis in megaloblastic anemia due to vitamin B12 or folate deficiency. Vitamin B12 corrected the lesion in vitamin B12 deficiency but not in folate deficiency. Tetrahydrofolate (FH4) and folic acid were effective in deficiency of vitamin B12 or folate, although in both deficiencies they were less effective than formyl-FH4. Methyl-FH4 was effective in folate deficiency but not in vitamin B12 deficiency. These results confirm the failure of methyl-FH4 utilisation in vitamin B12 deficiency. They suggest that if vitamin B12 is needed in the formylation of FH4, this is a minor role in provision of the correct coenzyme for thymidylate synthesis compared with its major role of provision of FH4 from methyl- FH4.
Karyotypically distinct subpopulations in acute leukemia with specific growth requirements
Authors: Lowenberg B , Hagemeijer A , Swart K 
Published: October 2019

Abstract
Bone marrow and blood cells of a patient with acute monoblastic leukemia with subclones marked with specific karyotypic abnormalities were investigated. In order to more precisely evaluate the proliferative abilities of these populations, leukemic cell enriched fractions were prepared and incubated in two colony assays. Colony forming cells of the disparate clones had growth advantages in different systems which shows that their proliferation depended on the presence of selective stimulatory factors in culture. In one assay, at diagnosis, colonies from the minor clone were demonstrated exclusively. It is suggested that the assays measured distinct cellular stages of myeloid differentiation and the findings indicate that prior to diagnosis the neoplasm had evolved into subsets with progressive dedifferentiation. Differences of growth in vitro correlated with the different roles of these clones in the clinical history of the disease. Approaches based on differential cloning of tumor stem cells as in this example, may be useful for discriminating biological properties of heterogeneous subpopulations within neoplasms, and may facilitate the cytogenetic recognition of minimal clones among composite malignant cell specimens.
Erythropoiesis in ha/ha and sph/sph mice, mutants which produce spectrin-deficient erythrocytes
Authors: Brookoff D , Maggio-Price L , Bernstein S , Weiss L 
Published: October 2019

Abstract
In order to characterize chronically accelerated erythropoiesis, we studied the ultrastructure of bone marrow and spleen of ha/ha and sph/sph mice, two mutants with profound hemolytic anemia secondary to deficiency of the erythrocyte membrane protein spectrin. The marrows and spleens of both varieties were extremely erythropoietic and were without histological abnormalities directly related to spectrin deficiency. Erythropoiesis was consistently associated with distinctive, dark branched cells which constituted large proportions of the stroma of the mutant spleens and marrow. These dark cells were not present in untreated and acutely bled controls. Plasma clot assays for erythroid progenitors revealed that CFU-E concentrations in the mutant marrows were significantly increased over those in untreated controls while BFU-E concentrations were approximately half. In addition, mutant CFU-E often gave rise to abnormal appearing colonies. Spectrin, though crucial to erythrocyte function is probably not important to the process of erythroid differentiation and maturation. The status of erythroid precursors in the marrows of the spectrin deficient mice is similar to that of mice subjected to an acute bleed. The divergent changes in CFU-E and BFU-E may indicate that these two cells play different roles in accelerated erythropoiesis. The dark cells that we describe are similar to stromal cells observed in models of the early stages of erythropoiesis.
A monoclonal antibody that detects expression of transferrin receptor in human erythroid precursor cells
Authors: Lebman D , Trucco M , Bottero L , Lange B , Pessano S , Rovera G 
Published: October 2019

Abstract
A monoclonal antibody, L5.1, obtained by immunizing a Balb/c mouse with HL60 human promyelocytic leukemia cells, was found to react with both HL60 cells and with the K562(S) cell line. This monoclonal antibody binds and immunoprecipitates a glycoprotein (Mr 87,000) present on the cell surface membrane of K562(S) as a disulfide bonded dimer. In competition experiments L5.1 competes with both transferrin and OKT9 (a known antitransferrin receptor antibody) for binding to target K562(S) erythroleukemia cells. Binding of both L5.1 and transferrin to the surface of K562(S) cells is inhibited by treatment with 12--O- tetradecanoyl-phorbol-13-acetate, and the extent and time course of inhibition is similar in both cases. Cell sorting analysis of normal human marrow cells incubated with L5.1 indicates that L5.1 reacts strongly with all the morphologically recognizable erythroid lineage precursors, from the pronormoblast to the orthochromatic normoblast, and with reticulocytes. Erythrocytes, myeloid elements, monocytes, megakaryocytes and platelets, peripheral blood B and T lymphocytes do not bind significantly with this antibody and only a small fraction of promyelocytes was reactive. Antibody L5.1 did not react with leukemic cells of patients with acute lymphoblastic, myeloblastic and promyelocytic leukemias, but it did react with some established B (1 of 5) and T (2 of 3) cell lines, and a myeloid (1 of 3) cell line, and with PHA-stimulated peripheral blood lymphocytes. The nonhemopoietic cell lines tested did not bind with L5.1 with the exception of a colorectal adenocarcinoma and a melanoma cell line, which were both strongly positive. The relationship of antibody L5.1 to other monoclonal antibodies that bind the transferrin receptor is discussed.
Specific protein and glycoprotein deficiencies in platelets isolated from two patients with the gray platelet syndrome
Authors: Nurden AT , Kunicki TJ , Dupuis D , Soria C , Caen JP 
Published: October 2019

Abstract
The gray platelet syndrome is a rare inherited platelet disorder characterized by the absence of alp ha-granules as observed by electron microscopy. Analysis of the glycoprotein composition of the platelets of 2 such patients by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed decreased or absent staining for carbohydrate of several high molecular weight glycoproteins. The major periodic acid Schiff (PAS) staining membrane glycoproteins were normally detected and were normally labeled with 125I during lactoperoxidase-catalyzed iodination. Analysis of the protein composition of gray platelets by single or two- dimensional SDS-PAGE followed by Coomassie blue staining revealed an apparent absence of GP Ig (thrombospondin), markedly reduced platelet fibrinogen and albumin concentrations, and severely reduced levels of 2 low molecular weight polypeptides exhibiting identical rates of migration on SDS-PAGE as platelet factor 4 and beta-thromboglobulin. SDS-PAGE profiles similar to those of the gray platelets were observed with normal human platelets that had undergone the release reaction induced by thrombin. Analysis of gray platelet proteins by crossed immunoelectrophoresis using a rabbit anti-human platelet antibody preparation and rocket immunoelectrophoresis using monospecific antisera confirmed the above findings and showed additional severe deficiencies of factor VIIIR:Ag and cold-insoluble globulin. In contrast, factor XIII (subunit A), a cytoplasmic protein, was normally detected. Our studies provide further evidence that circulating gray platelets specifically lack, or have markedly decreased concentrations of, the alpha-granule proteins.