bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factor VIII-von Willebrand factor requires calcium for facilitation of platelet adherence
Authors: Sakariassen KS , Ottenhof-Rovers M , Sixma JJ 
Published: October 2019

Abstract
The role of divalent cations in platelet adherence to deendothelialized human arteries in flowing blood was investigated in an annular perfusion chamber. Spreading of platelets on the subendothelium was impaired below 30 microM of free Ca2+ ions (Ca2+). When Ca2+ was replaced by Mg2+, adherence was unchanged in perfusates without exogenous factor VIII-von Willebrand factor (FVIII-vWF), but the ability of FVIII-vWF to support platelet adherence was lost. Binding of FVIII-vWF to the vessel wall was independent of divalent cations, but bound FVIII-vWF was only able to mediate adherence after exposure to Ca2+. Pretreatment of FVIII-vWF with the calcium chelator EGTA (10 mM) resulted in loss of the ability to facilitate platelet adherence, while the ristocetin cofactor activity remained intact. Full restoration of the ability to mediate platelet adherence could only be obtained by prolonged dialysis against Ca2+ in the millimolar range. These data indicate that divalent cations have at least two separate roles to play in supporting platelet adherence: (1) platelet spreading on the subendothelium requires Ca2+ or Mg2+; (2) FVIII-vWF should be exposed to Ca2+ to obtain its optimal biologic activity in supporting platelet adherence.
Tissue factor-dependent activation of tritium-labeled factor IX and factor X in human plasma
Authors: Morrison SA , Jesty J 
Published: October 2019

Abstract
Recent investigations have suggested that the activation of factor IX by factor VII/tissue factor may be an important alternative route to the generation of factor Xa. Accordingly, we have compared the tissue factor-dependent activation of tritium-labeled factor IX and factor X in a human plasma system and have studied the role of proteases known to stimulate factor VII activity. Plasma was defibrinated by heating and depleted of its factors IX and X by passing it through antibody columns. Addition of human brain thromboplastin, Ca2+, and purified 3H- labeled factor X to the plasma resulted, after a short lag, in burst- like activation of the factor X, measured as the release of radiolabeled activation peptide. The progress of activation was slowed by both heparin and a specific inhibitor of factor Xa, suggesting a feedback role for this enzyme, but factor X activation could not be completely abolished by such inhibitors. In the case of 3H-factor IX activation, the rate also increased for approximately 3 min after addition of thromboplastin, but was not subsequently curtailed. A survey of proteases implicated as activators of factor VII in other settings showed that both factor Xa and (to a much smaller extent) factor IXa could accelerate the activation of factor IX. However, factor Xa was unique in obliterating activation when present at concentrations greater than approximately 1 nM. Heparin inhibited the tissue factor-dependent activation of factor IX almost completely, apparently through the effect of antithrombin on the feedback reactions of factors Xa and IXa on factor VII. These results suggest that a very tight, biphasic control of factor VII activity exists in human plasma, which is modulated mainly by factor Xa. Variation of the factor IX or factor X concentrations permitted kinetic parameters for each activation to be derived. At saturation of factor VIIa/tissue factor, factor IX activation was significantly more rapid than was previously found in bovine plasma under similar conditions. The activation of factor X at saturation was slightly more rapid than in bovine plasma, despite the presence of heparin.
Radiation effects on cultured human monocytes and on monocyte-derived macrophages
Authors: Buescher ES , Gallin JI 
Published: October 2019

Abstract
Prior to administration, leukocyte transfusions are commonly irradiated with up to 5,000 R to eliminate lymphocytes and thereby prevent graft- versus-host disease in the recipient. It has been widely believed that phagocytes are resistant to this irradiation. In a recent report, we noted that phagocyte oxidative metabolism was compromised during preparation of white cells for transfusion. As part of our effort to examine the basis for this inhibition of phagocyte function during white cell preparation, we assessed the effects of irradiation on the long-lived monocytes that have been shown to persist at inflammatory foci posttransfusion. Human monocytes were irradiated for up to 3 min, receiving 2,500–5,000 R. This irradiation damaged human monocytes, significantly decreasing their in vitro survival for the first 3 wk of culture (p less than 0.02, irradiated versus control survival), and growth as assessed by two-dimensional cell size measurements during the first 2 wk of culture (p less than 0.01, irradiated versus control growth). Despite smaller cell size, total cell protein was significantly increased over time in irradiated cultures (p less than 0.001, irradiated versus control total protein per cell). Extracellular release of lysozyme and beta-glucuronidase per cell was not affected by irradiation, but extracellular lactate dehydrogenase (LDH) release was significantly increased after irradiation (p less than 0.001, irradiated versus control LDH release). Irradiated monocytes killed Listeria monocytogenes at a slower rate than the nonirradiated controls (p less than 0.05, irradiated versus control rate of killing). Thus, the data indicate that irradiation in doses used to prevent graft- versus-host disease in leukocyte transfusion recipients has a deleterious effect on in vitro human monocyte survival and function.
Control of oxygen affinity of hemoglobin in K562 cells induced by hemin
Authors: Wu Y , Dean A , Egan W , Schechter AN 
Published: October 2019

Abstract
The oxygen affinity of hemoglobin in K562 cells induced by hemin and the relationship between levels of 2,3-diphosphoglycerate (2,3-DPG) and hemoglobin have been investigated. Absorption spectra of induced cells indicate that the hemoglobin is oxygenated; oxygen dissociation curves are symmetric, with a P50 of 20 +/- 0.9 mm Hg, Hill coefficient of 2.5, and a normal temperature dependence. The intracellular pH measured by phosphorus 31 nuclear magnetic resonance (NMR) was 7.3. The amount of 2,3-DPG was determined by an enzymatic method and by 31P NMR. The level of 2,3-DPG in uninduced K562 cells, containing 0.5 pg of hemoglobin per cell, was low (5 +/- 0.5 mumole/10(8) cells), but increased to 64 +/- 5 mumole/10(8) cells upon induction of hemoglobin accumulation (to a final level of 20 pg hemoglobin/cell). For several experiments, there was a closely coordinated relationship between 2,3-DPG and hemoglobin levels, at about 1:1 stoichiometry of the two molecules. The time course of induction of hemoglobin, and of 2,3-DPG levels, are very similar; both processes are reversible. These data suggest that induction of hemoglobin synthesis in K562 cells by hemin results in hemoglobin-containing cells with normal oxygenation properties and that 2,3-DPG and hemoglobin levels are coordinately controlled in these cells. Elucidation of the mechanism of this effect should be of importance in understanding the erythroid-like differentiation of these cells.
Pharmacologic inhibition of thromboxane synthetase and platelet aggregation: modulatory role of cyclooxygenase products
Authors: Bertele V , Falanga A , Tomasiak M , Chiabrando C , Cerletti C , de Gaetano G 
Published: October 2019

Abstract
Dazoxiben , an imidazole-derived selective inhibitor of thromboxane A2 (TxA2) synthetase, prevented TxB2 synthesis in vitro in platelet-rich plasma from 16 normal subjects. Inhibition of TxB2 synthesis was accompanied by increased generation of PGE2, PGF2 alpha, and PGD2, as shown by radioimmunoassay, thin-layer radiochromatography, and high- resolution gas chromatography-mass spectrometry. Even at dazoxiben concentrations (40–80 microM) above those inhibiting TxB2 synthesis, platelet aggregation induced by threshold concentrations of arachidonic acid was inhibited in only 4 of 16 subjects, referred to as responders. The remaining 12 individuals were defined as nonresponders. The aggregating effect of arachidonic acid and of the prostaglandin- endoperoxide analog U-46619 was potentiated by PGE2 and prevented by PGD2 at concentrations within the range of those detected in dazoxiben - treated platelet-rich plasma. The antiaggregating effect of dazoxiben was counteracted by PGE2 (in responders) and was potentiated by PGD2 (in nonresponders). Platelets from responders and nonresponders did not differ in the amount of immunoreactive PGE2 material or in their sensitivity to U-46619 or PGD2. It is concluded that inhibition of thromboxane synthetase does not per se prevent platelet aggregation. The functional result of thromboxane suppression appears to be modulated by an interplay of the prostaglandin-endoperoxides, PGE2 and PGD2, which are formed in excess.
Intranuclear defect in beta-globin mRNA accumulation due to a premature translation termination codon
Authors: Takeshita K , Forget BG , Scarpa A , Benz EJ Jr 
Published: October 2019

Abstract
We have analyzed a cloned beta O-thalassemia (beta O-thal) gene from a patient doubly heterozygous for hemoglobin Lepore and beta O- thalassemia. Studies of 3H-uridine incorporation into beta-globin mRNA in this patient's erythroblasts suggested an intranuclear defect in both beta and Lepore (delta beta) mRNA synthesis, as did S1 nuclease analysis of nuclear RNA. However, the nucleotide sequence of the beta O- thal gene revealed only a single base change in codon 39 (CAG----UAG), which created a premature translation termination codon. The 5′ flanking sequence, including transcription promotor boxes and the mRNA initiation (CAP) site, were normal. The unexpected effect of this mutation on intranuclear beta-mRNA synthesis in vivo was studied by insertion of the cloned gene into a plasmid expression vector and transfection into tissue culture (COS-1) cells. beta-Globin mRNA produced by the transfected cells was assessed by S1 nuclease analysis. The beta O-39 thalassemia gene generated five- to tenfold less beta- mRNA than a normal beta-gene in both nuclear and cytoplasmic RNA, simulating the results observed in vivo. Moreover, the small amount of beta O-39 mRNA produced was as stable as normal beta-mRNA during an actinomycin D chase, ruling out rapid cytoplasmic turnover as a cause of the reduced accumulation. Cotransfection of the beta O-39 thalassemia gene with a mutant tyrosine suppressor tRNA gene resulted in restoration of the beta O-39 mRNA accumulation to near-normal levels. On the basis of these results, we suggest that the low levels of beta-mRNA known to exist in the common form of beta O-thalassemia, beta O-39 thalassemia, result from a lesion in transcription, or early posttranscriptional processes; the defect appears to be corrected by restoration of proper translational potential to the mutant mRNA, at least in a gene transfer-expression system in tissue-culture cells.
Do patients with thromboembolic disease have circulating platelet aggregates?
Authors: Kohanna FH , Smith MH , Salzman EW 
Published: October 2019

Abstract
Reports of circulating platelet aggregates (ie, microemboli) in thromboembolism and other vascular disorders are based on a method (Wu and Hoak , 1974) in which venous blood is collected via scalp vein needle and tubing into either formaldehyde, which fixes aggregates, or EDTA, which disperses them. The ratio of platelet counts in platelet- rich plasma (PRP) from the two blood samples after centrifugation is interpreted as a measure of platelet aggregates in the circulation in vivo. We compared this standard Wu and Hoak technique with a modified one, in which blood was drawn directly into a syringe, and with a third method that avoided centrifugation by counting single platelets in whole blood. Both modified techniques could detect aggregates generated in vitro with adenosine diphosphate (ADP). In 12 normal subjects, the three methods were equivalent, but in 37 patients with thromboembolic disorders, the standard Wu and Hoak method gave a lower ratio than the other methods. Similar results were found in a subset of eight patients with myocardial infarction. Heparin treatment of patients did not influence the results. The data suggest that formation of platelet aggregates occurred during venipuncture. Platelets may be hyperactive in patients with thromboembolic disease and may form aggregates in vitro during collection, but the concept of chronic microembolism in such patients should be reassessed.
DDAVP enhances platelet adherence and platelet aggregate growth on human artery subendothelium
Authors: Sakariassen KS , Cattaneo M , v.d. Berg A , Ruggeri ZM , Mannucci PM , Sixma JJ 
Published: October 2019

Abstract
The effect of intravenous 1-deamino (8-D-arginine)vasopressin (DDAVP) administration on platelet interaction with human artery subendothelium was investigated with flowing blood from five normal individuals and 12 patients with von Willebrand's disease (vWD). Three of the patients were diagnosed as vWD subtype I, four as subtype IIa, and five as subtype IIb. DDAVP administration to normals enhanced platelet adherence, in parallel with increasing plasma levels of factor VIII- related antigen ( FVIIIR :Ag) and ristocetin cofactor activity ( FVIIIR :RCF). Platelet aggregate formation was transiently increased within 90 minutes. Platelet adherence in patient blood before DDAVP infusion was subnormal. In patients with subtype I, administration of DDAVP normalized the bleeding time, enhanced the platelet adherence, and transiently improved the platelet aggregate formation. The platelet adherence was more corrected than would have been expected on the basis of the FVIIIR :Ag and FVIIIR :RCF levels. In patients with subtype IIa, infusion of DDAVP increased the FVIIIR :Ag levels approximately threefold, without affecting the FVIIIR :RCF levels, and in only two of four patients was a transiently enhanced platelet adherence with a corresponding shortening of the bleeding time observed. In patients with subtype IIb, administration of DDAVP increased the FVIIIR :Ag levels about threefold and the FVIIIR :RCF levels five to tenfold, but decreased the platelet adherence significantly. The bleeding time values were not normalized. A close association between the bleeding time values and corresponding platelet adherence values before and after DDAVP infusion was observed. Normalization of the bleeding time was paralleled with normalization of platelet adherence. We conclude that DDAVP improves the primary hemostasis by causing enhanced FVIII- vWF-mediated platelet adherence. DDAVP has little or no effect on the bleeding time in patients with subtype IIa and subtype IIb, because the platelet adherence is not normalized.
Efficacy of daunorubicin in the therapy of adult acute lymphocytic leukemia: a prospective randomized trial by cancer and leukemia group B
Authors: Gottlieb AJ , Weinberg V , Ellison RR , Henderson ES , Terebelo H , Rafla S , Cuttner J , Silver RT , Carey RW , Levy RN 
Published: October 2019

Abstract
The efficacy of the addition of intensive therapy with daunorubicin (45 mg/m2 IV on days 1, 2, 3) to an otherwise identical induction program consisting of vincristine, prednisone, and L-asparaginase was assessed in 177 previously untreated adults (greater than or equal to 20 years of age) with acute lymphocytic leukemia (ALL). In the prospectively randomized phase of the investigation, 46 patients received daunorubicin in induction, whereas 53 did not. The two groups were otherwise comparable for pretreatment variables. A complete response was observed in 38/46 patients (83%) treated with daunorubicin, compared to 25/53 (47%) induced with vincristine, prednisone, and L- asparaginase alone (P = .003). The high response rate attributable to the use of the anthracycline was confirmed by the nonrandomized treatment of 78 subsequent patients, in whom a complete response rate of 76% was attained. A common program for central nervous system therapy and for maintenance therapy was employed in 103 patients achieving complete response. Maintenance consisted of cycles of 6- mercaptopurine (6-MP) and methotrexate with periodic reinforcement with vincristine and prednisone. Maintenance therapy proved to be minimally toxic. The average duration of complete response was 15 months and was not affected by the induction program employed. Approximately 25% of responders are projected to remain in continuing complete response for 36 months. The failure of the daunorubicin-containing programs to produce a higher percentage of long-term survivors, despite the higher complete response rates achieved, was thought to be due to the use of a maintenance program that was weak in intensity and dependent on reinforcement with vincristine and prednisone. These data clearly establish the increased effectiveness of vincristine, prednisone, L- asparaginase, and daunorubicin, as compared to this combination without daunorubicin, in the induction of complete response in adults with ALL. The results support the concept of an intensive, rather than a conservative, chemotherapeutic approach as the most appropriate strategy for the treatment of adult ALL.
Antisickling effect of tellurite: a potent membrane-acting agent in vitro
Authors: Asakura T , Shibutani Y , Reilly MP , DeMeio RH 
Published: October 2019

Abstract
Potassium tellurite (K2TeO3) was found to be a potent antisickling agent that inhibited red cell sickling at concentrations less than 10 mumol/L. The inhibitory effect depended on the incubation time, with the effect increasing with longer incubation periods. Because tellurite causes swelling of red cells, and because the antisickling effect of tellurite correlated with the degree of red cell swelling, the antisickling effect of tellurite is assumed to be due to the decreased mean cell hemoglobin concentration. Swelling of red cells by tellurite was accelerated by the addition of reduced glutathione. Tellurite appears to be a new type of antisickling agent that interacts with the red cell membrane.
Diminished helper/suppressor lymphocyte ratios and natural killer activity in recipients of repeated blood transfusions
Authors: Kaplan J , Sarnaik S , Gitlin J , Lusher J 
Published: October 2019

Abstract
Immunologic abnormalities qualitatively similar to those seen in acquired immunodeficiency syndrome (AIDS), including a low helper/suppressor lymphocyte ratio and low natural killer (NK) activity, have been observed in many hemophiliacs receiving clotting factor concentrates. To determine whether these changes also occur after repeated blood transfusion, we measured helper/suppressor (T4/T8) ratios and NK activity in four groups of test subjects: (A) 30 subjects with sickle cell anemia (SCA) receiving monthly transfusions, (B) 30 nontransfused sickle cell anemia subjects, (C) 87 individuals with hemophilia or severe von Willebrand's disease, and (D) 30 normal controls. Like the hemophiliacs, transfused SCA subjects had low T4/T8 ratios and low NK activity compared to controls. Nontransfused SCA subjects had normal values. These findings suggest that a modest decrease in T4/T8 ratio and NK activity may be part of the normal immune response to repeated transfusion.
Simultaneous occurrence of terminal deoxynucleotidyl transferase and myeloperoxidase in individual leukemia blasts
Authors: Lanham GR , Bollum FJ , Williams DL , Stass SA 
Published: October 2019

Abstract
Cases of acute leukemia showing both terminal deoxynucleotidyl transferase (TdT) and myeloperoxidase (MPO) activities are usually classified as acute myelogenous leukemia (AML). Although some reports have implied overlap of TdT and MPO based on population percentages, direct evidence for simultaneous expression of TdT and MPO by a leukemic blast is lacking. By use of a simple new technique developed in our laboratory for identifying TdT and MPO in individual cells by light microscopy, we examined three cases of acute leukemia with both TdT and MPO positivity and found that the incidence of cells positive for both TdT and MPO was 0%, 1%, and 23%. Cytogenetic analysis showed a single leukemic clone in all patients, providing additional evidence that these leukemias arose from a single cell capable of expressing both MPO and TdT. These findings have implications for understanding the relation between MPO and TdT expression in leukemia.
Identification of pure and mixed basophil colonies in culture of human peripheral blood and marrow cells
Authors: Leary AG , Ogawa M 
Published: October 2019

Abstract
We present a colony assay system that allows in situ identification of human basophil/mast cell (basophil) colonies. In methylcellulose culture, in the presence of phytohemagglutinin-leukocyte conditioned media (PHA-LCM), human peripheral blood and bone marrow cells form colonies that can be distinguished by their unique morphological characteristics. Pure basophil colonies are diffuse, small colonies containing small, round, highly refractile cells. These characteristics of the constituent cells led us to the observation that a significant number of basophils are found in combination with eosinophils. The mixed eosinophil/basophil colonies have the distinctive elements of pure eosinophil and pure basophil colonies. Usually, these are diffuse colonies with compact clusters of slightly larger, darker-appearing cells. We also found colonies that contained basophils and neutrophils/monocytes, but this type could not be consistently identified by in situ morphology. Cytochemical analysis confirmed the metachromatic nature of the granules in the basophils. The presence of IgE receptors on the cells was documented by indirect immunofluorescent staining after passive sensitization with purified human IgE. Peripheral blood cells from six healthy volunteers formed 5.7 +/- 1.0 (mean +/- SEM) pure colonies in 2 X 10(5) cells. Cultures of bone marrow cells from patients with various types of anemia had 9.0 +/- 1.5 colonies in 10(5) cells. This is the first description of a colony assay system for in situ identification of a pure population of basophilic granulocytes.
Coenzyme function of cobalamin analogues from calf kidney
Authors: Thorndike J , Beck WS 
Published: October 2019

Abstract
Calf kidney has been used as a tissue source for the isolation of cobalamin analogues, which are defined here as cobalt-containing compounds of distinctive chromatographic behavior that are extractable from tissues by methods conventionally used to extract cobalamin and which, in radioisotope dilution assays, are more active with R-protein as binder than intrinsic factor and are relatively less active in microbiologic assays. Preparatory methods employed reverse affinity chromatography or a series of chemical extractions for the isolation of corrin followed by Dowex-50 chromatography. An analogue-containing fraction (peak 2) was eluted by acetate buffers between pH 4 and 5. This material was shown to contain cobalt, to migrate differently than the four cobalamins in Dowex-50 and paper chromatography, and to display a pattern of properties that is compatible with the above definition of cobalamin analogues. These analogues stimulated crude preparations of N5-methyltetrahydrofolate-homocysteine methyltransferase (EC 2.1.1.13) from Escherichia coli and rat liver at far lower concentrations (1–40 nmol/L) than the major cobalamins. No evidence of enzymatic conversion of cobalamin to analogue could be demonstrated.