bluuebunny/crossref_metadata_2025_split huggingface dataset:
Type IIB von Willebrand's disease: differential clearance of endogenous versus transfused large multimer von willebrand factor
Authors: Ruggeri ZM , Lombardi R , Gatti L , Bader R , Valsecchi C , Zimmerman TS 
Published: October 2019

Abstract
The abnormal multimeric composition of plasma von Willebrand factor in type IIB von Willebrand's disease is transiently corrected after infusion of 1-deamino-[8-D-arginine]-vasopressin. However, the larger multimers released into the circulation disappear more rapidly in these patients than in type I von Willebrand's disease or normals. We demonstrate that the larger multimers of normal von Willebrand factor transfused into a type IIB patient are cleared from the circulation more slowly than multimers of similar size endogenously released from tissue stores. The rate of disappearance of large von Willebrand factor multimers after infusion of cryoprecipitate is similar in IIB, IIA, and severe homozygous-like von Willebrand's disease. Platelets from the IIB patient exhibited normal ristocetin-induced binding of normal von Willebrand factor. However, like normal platelets, they bound IIB von Willebrand factor at lower ristocetin concentrations than required for normal von Willebrand factor. These findings provide evidence that absence of the larger multimers from IIB plasma is related to a molecular abnormality of von Willebrand factor rather than to enhanced affinity of abnormal tissue or cellular binding sites, as is the case in the recently described “pseud” von Willebrand's disease and “platelet-type” von Willebrand's disease.
Platelet-bound IgM in autoimmune thrombocytopenia
Authors: Nel JD , Stevens K , Mouton A , Pretorius FJ 
Published: October 2019

Abstract
Elevated levels of platelet-bound IgG (PA-IgG) are a feature of autoimmune thrombocytopenia (ATP), but it is well documented that this does not occur in all cases. This has led us to investigate the role of platelet-bound IgM (PA-IgM) in these patients using a quantitative enzyme-linked immunosorbent assay (ELISA). Forty-five determinations of PA-IgM and PA-IgG were done on 24 patients with ATP. Elevated levels of PA-IgM were found in 93.3% of the determinations, while PA-IgG was elevated in only 71.7%. In 64.4% of determinations, both were elevated. Elevated PA-IgM or PA-IgG alone occurred in 28.9% and 6.7% of determinations, respectively. These results show the hitherto unrecognized frequent involvement of PA-IgM in ATP and suggests that a complex interrelationship exists between the two immunoglobulin classes in ATP. Some of the possibilities that might explain this interrelationship are discussed.
Generalized hexokinase deficiency in the blood cells of a patient with nonspherocytic hemolytic anemia
Authors: Rijksen G , Akkerman JW , van den Wall Bake AW , Hofstede DP , Staal GE 
Published: October 2019

Abstract
In a patient with nonspherocytic hemolytic anemia, a hexokinase deficiency was detected in the red cells (residual activity about 25% of normal) and in blood platelets (20%-35% of normal activity). Although the total hexokinase activity in lymphocytes was normal, the amount of hexokinase type I was decreased to about 50% of normal. However, the deficiency was compensated for by the appearance of type III hexokinase. Compartmentation studies with controlled digitonin- induced cell lysis showed that this type III enzyme was localized in the cytosol, while almost all hexokinase activity in normal lymphocytes is particulate. No abnormal lymphocyte functions could be detected. The patient was homozygous for the defect. The parents and three of five sibs of the patient were apparently heterozygous with residual activities of 50%-67% of normal in their red cells, but did not show any clinical signs of hexokinase deficiency. The variant enzyme had a slightly decreased affinity for MgATP2- and a strongly increased inhibition constant for glucose-1,6-P2. Affinity for glucose, heat stability, and pH optimum were normal. In the electrophoretic pattern of red cell hexokinase, only one subtype of hexokinase I could be detected, while in normal red cells, at least three subtypes are present. In the heterozygous individuals, no enzymatic abnormalities could be detected, except for an aberration in the electropherogram of one sib.
Augmentation by platelets of granulocyte aggregation in response to chemotaxins: studies utilizing an improved cell preparation technique
Authors: Redl H , Hammerschmidt DE , Schlag G 
Published: October 2019

Abstract
Considerable evidence exists to suggest roles for both platelets and granulocytes (PMNs) in pulmonary injury in shock. While believing that the major contributions of the two cell types are sequential, in vitro observations suggested that direct interactions between granulocytes and platelets might also amplify tissue damage. Using isotonic Percoll density gradients to isolate PMNs, we therefore studied the effect of deliberate platelet contamination on PMN aggregation. PMN aggregation in response to N-formyl-met-leu-phe or activated complement was enhanced by the presence of 1 platelet/PMN, an effect that became maximal at 16 platelets/PMN (p less than 0.01); large mixed aggregates were formed. Lysed, aspirinated, and indomethacin-treated platelets retained their augmentative capacity, as did platelets washed by gel filtration. The effect was not mimicked by the addition of histamine or serotonin to PMN preparations. None of these platelet preparations augmented lysosomal enzyme release. We conclude that platelets augment PMN aggregation, both by forming giant mixed PMN/platelet aggregates and also by producing a labile augmentative substance, the production of which may be independent of thromboxane synthesis. We propose that direct as well as sequential platelet/PMN interactions may be important in tissue injury in shock.
Exposure of platelet fibrinogen-binding sites by collagen, arachidonic acid, and ADP: inhibition by a monoclonal antibody to the glycoprotein IIb-IIIa complex
Authors: Di Minno G , Thiagarajan P , Perussia B , Martinez J , Shapiro S , Trinchieri G , Murphy S 
Published: October 2019

Abstract
Following stimulation with adenosine diphosphate (ADP), collagen, or arachidonic acid, unstirred human platelet suspensions bind 125I- fibrinogen in a reaction that reaches completion within 30 min. Scatchard analysis of these binding data reveals two sets of binding sites with all 3 agents: a high affinity site (Kd 0.029–0.045 microM) binding 1000–1600 fibrinogen molecules per platelet, and a lower affinity site (Kd 1.2–2.0 microM) binding 46,000–76,000 fibrinogen molecules per platelet. At a concentration of apyrase that inhibited ADP-induced fibrinogen binding by greater than 85%, fibrinogen binding induced by collagen and arachidonic acid was only partially affected. This suggests that fibrinogen binding induced by collagen or arachidonic acid does not require released ADP. We isolated a monoclonal antibody, B59.2, which precipitated the glycoprotein IIb- IIIa complex from solubilized platelet membranes. Binding of labeled antibody to platelets before or after exposure to ADP, collagen, or arachidonic acid showed a single class of approximately 22,000 binding sites with Kd 0.019 microM. Binding of B59.2 was complete within 1 min and was not inhibited by EDTA. Preincubation of platelet suspensions with a 2.1 microM concentration of B59.2 caused inhibition of secretion and aggregation, but not of thromboxane-B2 synthesis, in response to 1 microgram/ml collagen, 40 microM arachidonic acid, or 4 microM ADP, concentrations of aggregating agents that produced complete aggregation and secretion in the absence of B59.2. At this concentration of B59.2, fibrinogen binding to stimulated platelets was inhibited by approximately 45%-55%. These data demonstrate that collagen and arachidonic acid can expose fibrinogen binding sites independently of released ADP; and that the glycoprotein IIb-IIIa complex is involved in secretion, aggregation, and fibrinogen binding, but not in thromboxane synthesis occurring in response to collagen, arachidonic acid, or ADP.
Thrombin and ionophore A23187-induced dense granule secretion in storage pool deficient platelets: evidence for impaired nucleotide storage as the primary dense granule defect
Authors: Lages B , Holmsen H , Weiss HJ , Dangelmaier C 
Published: October 2019

Abstract
The secretion of the dense granule constituents ATP, ADP, calcium, pyrophosphate (PPi), and orthophosphate (Pi), and the release of magnesium induced by thrombin and the divalent cation ionophore A23187 have been quantitated directly in gel-filtered platelets from patients with storage pool deficiency (SPD). Both the contents and the maximal amounts of the dense granule constituents secretable by thrombin were decreased in all the patients studied, while the nonsecretable, retained amounts of these substances were identical in SPD and normal platelets. In response to both thrombin and A23187, the amounts of secretable ATP and ADP were strongly correlated in the platelets of individual patients; in contrast, secretable calcium showed no correlation with the nucleotides, and significant amounts of calcium were secreted in the total absence of nucleotide secretion in the platelets of several patients. The contents of magnesium were normal in all patients, and approximately 12% of platelet magnesium was liberated by thrombin in both SPD and normal platelets. A23187 induced the release of up to 70% of the magnesium content of normal platelets, but released significantly less (46%) magnesium from SPD platelets. Platelet aggregation induced by A23187 in platelet-rich plasma was also markedly decreased in SPD platelets. The correlations among secretable dense granule constituents suggest the presence in SPD platelets of abnormal dense granule structures that sequester calcium and other constituents but little or no adenine nucleotides, and are thus consistent with a hypothesis that impaired nucleotide transport and/or storage may be the primary dense granule defect in this disorder. In addition, these results demonstrate that certain responses to A23187 are impaired in SPD platelets.
Passive participation of fixed platelets in aggregation facilitated by covalently bound fibrinogen
Authors: Agam G , Livne A 
Published: October 2019

Abstract
The role of fibrinogen in interplatelet recognition during aggregation was examined by combining two cell types: fresh platelets (in limiting density) activated by thrombin or A23187, and formaldehyde-fixed platelets, bearing cross-linked fibrinogen. The fixed platelets did not aggregate by themselves, nor with resting platelets, but were capable of interacting with activated platelets and of participating passively in aggregation. The participation, expressed by enhanced aggregation, was assayed by the conventional turbidometric traces and by cosedimentation of fixed 3H-platelets with aggregates of fresh platelets. Platelet suspensions, prepared without special means to avert spontaneous activation, retained plasma fibrinogen to the extent of 50 micrograms/ml of a suspension containing 10(8) platelets, and the derived fixed platelets participated in aggregation, independently of added fibrinogen. The capability of such fixed platelets to participate in aggregation was sensitive to proteolytic digestion and to massive acetylation. When platelet separation was aided by apyrase or aspirin, PGE1 and gel filtration, the residual plasma fibrinogen was limited to 0.4 micrograms/ml of 10(8) platelet suspension. The derived fixed platelets were incapable of participating in aggregation unless fibrinogen was added prior to fixation. The affixed fibrinogen could not be replaced by soluble fibrinogen or affixed albumin. It is concluded that fibrinogen, which binds to platelets upon activation or is linked to them covalently, is a recognition site for platelet- platelet interaction during aggregation.
Chromosome aberrations in T lymphocytes carrying adult T-cell leukemia- associated antigens (ATLA) from healthy adults
Authors: Fukuhara S , Hinuma Y , Gotoh YI , Uchino H 
Published: October 2019

Abstract
Chromosomes were studied in cultured T lymphocytes carrying adult T- cell leukemia-associated antigens (ATLA) that were obtained from five Japanese anti-ATLA seropositive healthy adults. Chromosomally abnormal cells were observed in three of the five healthy adults, and these cells were clonal in two subjects. All cells examined in one subject had rearrangements of chromosome nos. 7 and 14. Clonal cells from the second had a minute chromosome of unknown origin. A few cells in the third had nonclonal rearrangements of chromosomes. Thus, ATLA-positive T lymphocytes in some anti-ATLA seropositive healthy people have chromosome aberrations.
Characterization of non-human primate antisera to acute lymphoblastic leukemia (ALL): evidence for unique antigen(s) on childhood ALL of "T" phenotype
Authors: Mohanakumar T , Coffey TW , Vaughn MP , Russell EC , Conrad D 
Published: October 2019

Abstract
A non-human primate antiserum was prepared to acute lymphoblastic leukemia of T-cell phenotype (T-ALL) and, after absorptions with normal blood elements, reacted by immunofluorescence and microcytotoxicity to all the T-ALL tested. In addition, the antiserum reacted with cells from about 70% of the common ALL studied and immunoprecipitated the common ALL antigen of 100,000 daltons. However, when the anti-T-ALL serum was absorbed with with lymphoblasts from common ALL, it failed to react with common ALL lymphoblasts, yet reacted significantly with cells from patients with T-ALL phenotype and defined a 100,000-dalton membrane component not found on common ALL lymphoblasts. In addition, sequential immunoprecipitation of 125I-labeled T-ALL membranes by anti- common-ALL serum followed by anti-T-ALL serum detected the T-ALL membrane component of 100,000 daltons that was not found on common ALL. Thus, our results demonstrate the presence of of a unique human T-ALL antigen present on all T-ALL distinct from the common ALL antigen.
Endogenous protein phosphorylation by resting and activated human neutrophils
Authors: Andrews PC , Babior BM 
Published: October 2019

Abstract
NADPH oxidase is an enzyme in the plasma membrane of the neutrophil that catalyzes the production of O2-, a species central to the oxygen- dependent killing mechanisms of this cell. The oxidase is dormant in resting cells and is activated upon the addition of a stimulus. Neutrophils of patients with chronic granulomatous disease (CGD) manifest no oxidase activity when stimulated. The possible role of protein phosphorylation in the activation of NADPH oxidase was examined in normal and CGD neutrophils by measuring the incorporation of 32Pi into proteins as determined by gel electrophoresis followed by autoradiography. Resting neutrophils from normal subjects exhibit at least 40 distinct phosphoprotein bands. The level of phosphorylation of these bands was examined after the addition of phorbol myristate acetate (PMA), opsonized zymosan, digitonin, N-formyl-methionyl- phenylalanine (FMLP), or NaF. PMA and opsonized zymosan increased the phosphorylation of a set of 6 protein bands. Digitonin and FMLP consistently caused the phosphorylation of 4 of these protein bands, while NaF failed to induce increased phosphorylation of any protein band. All activators tested caused the dephosphorylation of one specific protein band. The time course of phosphorylation (dephosphorylation) was examined using PMA as the activating agent. Increased phosphorylation of one protein band was evident by 12 sec after the addition of PMA. The most slowly phosphorylated protein band did not slow evidence of change until 5 min after the addition of PMA. Three of the phosphoproteins examined were phosphorylated either earlier than or concomitant with the activation of NADPH oxidase. CGD neutrophils were compared with normal cells for their ability to phosphorylate proteins in response to PMA. The phosphoprotein banding patterns of CGD neutrophils were identical with those of normal neutrophils in both the resting and activated states. The evidence presented shows that the phosphorylation of proteins is a prominent feature of neutrophil metabolism. The striking similarity of phosphorylation changes induced by the various activators tested suggests that protein phosphorylation may play a role in some aspects of neutrophil activation. Evidence was not obtained, however, regarding a link between protein phosphorylation and activation of NADPH oxidase.
Mechanism of thrombin binding to endothelial cells
Authors: Bauer PT , Machovich R , Aranyi P , Buki KG , Csonka E , Horvath I 
Published: October 2019

Abstract
The interaction of human alpha-thrombin with mini-pig aortic endothelial cells was studied using 125I-labeled enzyme. Equilibrium between bound and free thrombin was attained within 1 min, and the Klotz-Hunston equations indicated two populations of binding sites. Approximately 30,000 sites/cell belonged to the high-affinity class with a Kd of about 3 x 10(-8) M. Modification of two lysine residues of thrombin with pyridoxal 5′-phosphate (PLP2-thrombin) destroyed the high- affinity binding and about three-fourths of the low-affinity bindings. When the lysine residue of thrombin involved in heparin binding was protected with heparin against chemical modification (PLP-thrombin), the modified enzyme remained similar to the native one with respect to cellular binding, with some loss of low-affinity binding only. Heparin, in a tenfold molar excess to enzyme, inhibited the binding of the native as well as the PLP-thrombin, whereas it did not influence the interaction between PLP2-thrombin and the cell. Since heparin might interfere with both the enzyme and the cell, the binding of heparin to endothelial cells was also examined. The results revealed that 3H- heparin also bound to cells. This binding was characterized by a Kd of 3 x 10(-7) M, approximately 10(6) sites/cell. Furthermore, thrombin bound to endothelial cells was released by antithrombin III. On the basis of these and other data in the literature, a model is proposed for the mechanism of the binding of thrombin to endothelial cells.
The role of calcium in lymphocyte proliferation. (An interpretive review)
Authors: Lichtman AH , Segel GB , Lichtman MA 
Published: October 2019

Abstract
A small quantity of extracellular calcium is required for the stimulation of lymphocytes by mitogens such as plant lectins. Lectin binding to the lymphocyte surface and early postbinding events that eventually lead to DNA synthesis are calcium dependent. Mitogenic lectins such as PHA and Con-A rapidly increase the size of an exchangeable pool of cell calcium and cause a smaller rise in intracellular ionized calcium. The increase in ionized calcium is so small (100–200 nM), however, that no increase in total cell calcium is measurable. When lymphocytes are stimulated by a lectin, the rate of calcium entry into the cell increases, but the plasma membrane calcium extrusion pump can prevent the total cell calcium from increasing measurably. The calcium ionophore A23187 is a lymphocyte mitogen and causes an increase in the exchangeable, ionized, and total cell calcium. The former two effects may be causal in mitogenesis; the latter effect is cytotoxic. With A23187 treatment, the rate of calcium influx exceeds the maximum rate of the plasma membrane extrusion pump and cell calcium increases in proportion to the concentration of A23187. The mitochondria, by virtue of their high membrane potential, provide a sink for the buffering of cytoplasmic calcium after A23187 treatment. Thus, the plasma membrane or mitochondria regulate the distribution of lymphocyte calcium when the cell is stimulated by mitogenic lectins or ionophores. The evidence strongly suggests that an alteration in calcium pools or an increase in cytoplasmic ionized calcium plays a role in the initiation of the biochemical reactions that lead to mitogen-induced lymphocyte proliferation in vitro and, perhaps, to the immune response.
Species-dependent variations in erythrocyte membrane skeletal proteins
Authors: Whitfield CF , Mylin LM , Goodman SR 
Published: October 2019

Abstract
Two mammalian species (porcine and murine) have erythrocytes that are being widely used to study membrane protein synthesis and red cell aging. Erythrocytes of these species however, are significantly smaller than those of the human. Before results obtained from study of these red cells can be applied to human cells, the membrane skeleton of these species must be investigated to determine if the skeletal elements are equivalent. Both pig and mouse bands 4.1b were of lower molecular weight than human 4.1b, and the a/b ratio was lower. In each species, 4.1a and b were sequence-related phosphoproteins, and yielded substantially different one-dimensional peptide maps. Band 3 of pig and mouse erythrocytes had a higher molecular weight than human band 3 and also had differing one-dimensional peptide maps after limited proteolytic cleavage with three different enzymes. In each species, free band 3 and band 3 bound to the membrane skeleton had identical peptide maps. Other major membrane skeletal components (spectrin, actin, and bands 2.1 and 4.2) seem to be very similar in molecular weight in various species. These results demonstrate that the molecular weights and relative proportions of the membrane skeletal elements are species dependent.
Monoclonal antibodies specific for globin chains
Authors: Stamatoyannopoulos G , Farquhar M , Lindsley D , Brice M , Papayannopoulou T , Nute PE 
Published: October 2019

Abstract
Six monoclonal antibodies specific for human globin chains are described. They are produced by stable clones obtained by raising hybridomas using cells of mice immunized with either adult or fetal hemoglobin. Characterization of the antibodies included testing against tetrameric human and other animal hemoglobins, isolated hemoglobin chains, and when indicated, cyanogen bromide fragments. Monoclonals 16- 2 and 37–8 are beta-chain specific. Antibody 31–2 recognizes an antigenic determinant common to the alpha and beta subunits. Monoclonal 30–3 recognizes determinants best expressed in the alpha 2 beta 2 tetramer. Antibody 45–1 recognizes a determinant common to beta and gamma subunits, while antibody 51–7 is gamma-chain specific. None of the monoclonal antibodies recognizes mouse hemoglobin, and they display significant differences in binding to hemoglobins of various species. The species-specific reactions and the knowledge of the primary structures of globins allowed deductions about the antigenic sites recognized by two of the monoclonals (16–2 and 45–1). These antihemoglobin monoclonal antibodies will provide useful probes for studying hemoglobin expression in vivo and in vitro.