bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two populations of erythroid cell progenitors in paroxysmal nocturnal hemoglobinuria
Authors: Rotoli B , Robledo R , Scarpato N , Luzzatto L 
Published: October 2019

Abstract
We have grown erythroid cell colonies from two patients with paroxysmal nocturnal hemoglobinuria (PNH). At 11 to 13 days, individual bursts were picked and incubated for 24 hours with 3H-leucine in order to label total cell protein (mainly hemoglobin). After appropriate washing, each burst was subjected to a miniaturized acidified serum test, and lysis was measured by the release of radioactivity. In bursts from normal controls, lysis was 19% +/- 13% SD. By contrast, of 58 bursts from PNH patients, 14 had lysis similar to that of controls (mean 15.4% +/- 10.6%), while 44 had lysis ranging from 42.2% to 85.8% (mean 70.3% +/- 10.4%). Colonies sensitive to acidified serum were acetylcholinesterase (AchE) negative, whereas normal colonies were AchE- positive. Thus, based on two independent criteria, a dual population of erythroid burst-forming units (BFU-E) can be demonstrated in PNH. These data confirm directly the somatic mutation model of the pathogenesis of PNH, and by these methods the relative sizes of the normal and the PNH cell populations can be measured at the level of the erythroid cell precursors.
Factor IX and prothrombin in amniotic fluid and fetal plasma: constraints on prenatal diagnosis of hemophilia B and evidence of proteolysis
Authors: Thompson AR 
Published: October 2019

Abstract
Potential limitations of prenatal diagnosis of hemophilia B, as compared to hemophilia A, include (1) occurrence of far more frequent defects with abnormal circulating antigen, (2) lower levels of factor IX in fetal plasma at 16 to 20 weeks gestation, and (3) the presence of factor IX antigen in amniotic fluid. In addition, proteolysis could occur, especially with amniotic fluid contamination of fetal plasma. A sensitive polyclonal immunoradiometric assay for factor IX antigen was used to characterize the range of levels in amniotic fluids and fetal plasma samples. To assess for altered forms, factor IX species were compared to those of a homologous clotting factor, prothrombin. Fourteen postmortem abortus blood samples from fetuses of 14 to 23 weeks gestation had factor IX antigen levels that averaged 5.1 U/dL and ranged from 1.7 to 15 U/dL. Amniotic fluid factor IX antigen averaged 2.9 U/dL, with a range from 1.4 to 8.5 U/dL in 19 separate amniocentesis samples. Thus, in a male fetus at risk of hemophilia B and with a low circulating level of gene product, mixture of fetal plasma with amniotic fluid could severely limit prenatal diagnosis, assuming that the amniotic fluid factor IX is of maternal origin. Despite rapid processing of amniotic fluid samples, the prothrombin was extensively cleaved, suggesting that it had been activated in vivo. On gel electrophoresis of amniotic fluid samples, however, factor IX was only minimally cleaved. In the postmortem fetal blood specimens, prothrombin was partially cleaved. On crossed-immunoelectrophoresis, fetal plasma prothrombin showed decreased migration in calcium, compared to EDTA, indicative of mature gamma-glutamyl carboxylation. The latter presumably resulted from fetal hepatic synthesis.
Passive material behavior of granulocytes based on large deformation and recovery after deformation tests
Authors: Evans E , Kukan B 
Published: October 2019

Abstract
In order to better understand the in vivo rheologic behavior of white cells, we have studied the time-dependent deformability, recovery, and mechanical activation of blood granulocytes. We have used micropipette aspiration methods to measure the large deformation response and recovery after deformation characteristics of neutrophils as functions of time, temperature, and collecting media. The cell response in the pipette experiment was characterized by three time domains: the first phase was the passive deformation response to the fixed suction pressure; the second phase was an obvious transition from the passive to active motile cellular state where the cell exhibited erratic length changes in the pipette; and the third phase was the steady recovery after the suction pressure had been zeroed. Tests on white cells were carried out with three different anticoagulants to evaluate the effect of calcium on deformation and recovery behavior; also, cells were separated by centrifugation in high molecular weight dextran to determine whether or not collection and separation procedures affected the cell properties. Our results have shown that the passive deformation of granulocytes into the pipette was a continuous flow process with no approach to a static deformation limit. In addition, there was an obvious threshold pressure below which the cell would not deform and enter the micropipette. For suction pressures significantly above the threshold, granulocytes were continuously deformed with a similar functional dependence on time. The coefficient of proportionality between aspiration length and time, as well as the exponent, depended on suction pressure, pipette dimension, and temperature. It was observed that the granulocytes always recovered to the spherical state after deformation, independent of the extent of deformation or location where the cell was aspirated. Based on the recovery behavior, plus the dependence of the pressure threshold on pipette size, we propose the concept that the granulocyte membrane and cortical shell behave like a “contractile surface carpet” under tension, where the cell interior responds passively like a highly viscous liquid. The membrane cortex appears to be subject to a persistent stress (tension) of about 10(-2) dyne/cm. Our observations of passive to active transition in the pipette suction experiment indicated that granulocytes may be stimulated by deformation at room temperature. This study represents the first detailed investigation of the large deformation behavior of granulocytes, and the results indicate a simple structural model to represent the passive rheologic behavior of the granulocyte.
Dense cells in sickle cell anemia: the effects of gene interaction
Authors: Fabry ME , Mears JG , Patel P , Schaefer-Rego K , Carmichael LD , Martinez G , Nagel RL 
Published: October 2019

Abstract
In an attempt to uncover potential genetic sources of the clinical diversity of sickle cell anemia, we have characterized homozygous SS patients in the following ways: percentage of dense red blood cells (% F4) as determined from Percoll-Stractan continuous density gradients, alpha gene deletion, average percentage of hemoglobin F (% HbF), hemoglobin in g/dL, age, and sex. We find that alpha 4 individuals have a higher % F4 (mean 24% +/- 15%) than alpha 3 individuals (mean 12% +/- 8%) (P less than .005). Multivariate analysis demonstrated a significant correlation among % F4 levels and alpha-gene number and % HbF, and an interaction between the last two variables. The other variables considered did not significantly alter this model. As reported before, with fewer samples, we find that in the first ten years of life of SS individuals, the frequency of alpha gene deletion is 17%, which is comparable to that in the general black population, while in the group over 20 years of age, the frequency rises to 49%, implying that alpha thalassemia is associated with longer survival. These results indicate that it is necessary to consider sickle cell anemia not only as a single gene defect, but also as a disease whose clinical expression is the result of a group of genes capable of interacting at the phenotypic level.
Production of F cells in sickle cell anemia: regulation by a genetic locus or loci separate from the beta-globin gene cluster
Authors: Boyer SH , Dover GJ , Serjeant GR , Smith KD , Antonarakis SE , Embury SH , Margolet L , Noyes AN , Boyer ML , Bias WB 
Published: October 2019

Abstract
Levels of fetal hemoglobin (HbF) bearing reticulocytes (F reticulocytes) range from 2% to 50% in patients with sickle cell (SS) anemia. To learn whether any portion of such variation in F cell production is regulated by loci genetically separable from the beta- globin gene cluster, percentages of F reticulocytes were compared in 59 sib pairs composed solely of SS members, including 40 pairs from Jamaica and 19 from the United States. We reasoned that differences in F reticulocyte levels might arise (1) from any of several kinds of artifact, (2) via half-sib status, or (3) because one or more genes regulating F cell production segregate separately from beta S. We minimized the role of artifact by assay of fresh samples from 84 SS individuals, including both members of 38 sib pairs. In 78 of the 84 subjects, serial values for percent F reticulocytes fell within 99.9% confidence limits or were alike by t test (P greater than or equal to .05). This left 32 sib pairs for which F reticulocyte levels in each member were reproducible. When sib-sib comparisons were limited to these 32 pairs, percentages of F reticulocytes were grossly dissimilar within 12 Jamaican and 3 American sibships. Within them, the probability that sibs were alike was always less than or equal to .005 and usually less than or equal to 10(-4). We next minimized the contribution of half-sibs among Jamaicans by a combination of paternity testing and sib-sib comparison of beta-globin region DNA restriction fragment length polymorphisms, especially among discordant pairs. We thereafter concluded that at least seven to eight Jamaican pairs were composed of reproducibly discordant full sibs. There is thus little doubt that there are genes regulating between-patient differences in F cell production that are separate from the beta-globin gene cluster. Still unanswered is (1) whether or not these genes are actually linked to beta S, (2) why F reticulocyte levels in Americans tend to be lower than in Jamaicans, and (3) whether or not differences in F cell production among SS patients are regulated by several major loci or by only one.
Differentiation of a human monocytic cell line by 1,25-dihydroxyvitamin D3 (calcitriol): a morphologic, phenotypic, and functional analysis
Authors: Rigby WF , Shen L , Ball ED , Guyre PM , Fanger MW 
Published: October 2019

Abstract
Several recent studies have suggested a role for 1,25-dihydroxyvitamin D3 (calcitriol) in myeloid differentiation. We have examined the effects of calcitriol on the U937 monoblast cell line and found that calcitriol, at near physiologic concentrations, is a potent inhibitor of U937 growth. Moreover, calcitriol induces differentiation to a monocyte-macrophage phenotype marked by enhanced alpha-naphthyl esterase staining. Morphologic changes were attended by de novo induction of the myeloid specific antigen detected by the monoclonal antibody AML-2–23, as well as dramatic increases in Fc receptors for IgG. In addition, calcitriol induced U937 cells to perform phagocytosis and antibody-dependent cellular cytotoxicity. These results indicate the potential activity of calcitriol in myeloid differentiation and additionally suggest a role for calcitriol in monocyte-macrophage activation.
Progressive preleukemia with a chromosomally abnormal clone in a kindred with the Estren-Dameshek variant of Fanconi's anemia
Authors: Nowell P , Bergman G , Besa E , Wilmoth D , Emanuel B 
Published: October 2019

Abstract
One of two sisters with hypoplastic anemia and increased chromosomal fragility, but no clinical stigmata of Fanconi's anemia (FA), progressed to preleukemia (with a clone of chromosomally abnormal cells in the bone marrow), and then to acute nonlymphocytic leukemia. The findings indicate that constitutional genetic instability can lead to karyotypically aberrant neoplastic clones in the Estren-Dameshek variant of FA as well as in the more typical chromosomal fragility syndromes.
Two-cycle timed-sequential chemotherapy for adult acute nonlymphocytic leukemia
Authors: Vaughan WP , Karp JE , Burke PJ 
Published: October 2019

Abstract
Based on a series of clinical and laboratory studies of leukemia cell kinetics and responses to chemotherapy, we have developed an intensive timed-sequential regimen of daunorubicin and high-dose infusion 1-beta- D-arabinofuranosyl cytosine for the treatment of adult acute nonlymphocytic leukemia. Of the first 34 patients achieving complete remission (CR) with a single cycle of this therapy, four (12%) remain in complete remission without further therapy after a minimum of five years of follow-up. Treatment of relapsed patients with a second course of the same regimen at relapse and no chemotherapy in second remission increased to seven (21%) the number of patients expected to remain in remission for four years or more from their last chemotherapy. Beginning in 1980, however, we gave all consenting adults a second cycle of this chemotherapy in early first remission. Of the first 25 patients treated with a second cycle of this chemotherapy in early first remission, there was one toxic death, but 11 patients (44%) remain in CR with a median follow-up of almost three years.
A reassessment of the energy requirements for neutrophil migration: adenosine triphosphate depletion enhances chemotaxis
Authors: Lane TA , Lamkin GE 
Published: October 2019

Abstract
In view of previous studies demonstrating a significant correlation between adenosine triphosphate (ATP) depletion and impairment of chemotaxis (CTX) during granulocyte (PMN) storage, we sought to quantitate the relationship between CTX and PMN energy metabolism. We incubated PMNs at 37 degrees C with 2-deoxyglucose (2-dg) in the presence of 5 mmol/L glucose. As expected, ATP inhibition by 2-dg was time-dependent (T 1/2, 18 minutes) and dose-dependent, with half- maximal inhibition of ATP (ID50) with 1.3 +/- .3 mmol/L 2-dg. Similar concentrations of 2-dg inhibited lactate generation, phagocytosis, superoxide anion generation, and degranulation. The random migration of PMNs was inhibited by somewhat higher concentrations of 2-dg (ID50, 12 mmol/L). In contrast, up to 40 mmol/L 2-dg did not inhibit CTX toward synthetic peptides or activated serum. In fact, 2-dg consistently increased the CTX of PMNs toward 10(-8) mol/L f-Met-Leu-Phe (fMLP), to a maximum of 450% of control CTX using 15 mmol/L 2-dg. Half-maximal stimulation (ED50) of CTX occurred at 6.3 +/- 1.0 mmol/L 2-dg. Although maximal CTX toward optimal concentrations of fMLP was consistently increased with 2-dg, the ED50 of CTX to fMLP was unchanged (ED50 with glucose, 2.0 +/- 0.6 nmol/L fMLP; ED50 with 2-dg 2.2 +/- 0.7 nmol/L fMLP), and 2-dg did not increase fMLP receptors. In the absence of glucose, 2-dg exerted similar effects on ATP and CTX, but at doses 30- to 50-fold lower than in the presence of glucose. Other glycolytic inhibitors (iodoacetamide and sodium fluoride) exerted similar effects. Additional studies indicated that CTX enhancement by 2-dg (a) required Mg++ but not Ca++, (b) occurred with PMNs from a patient with chronic granulomatous disease, (c) was unaltered in the presence of inhibitors of proteolysis, (d) was not due to generation of a soluble agent, (e) was not due to alterations in PMN adherence, and (f) was not due to inhibition of glycosylation. We conclude that the chemotaxis, but not the random migration, of PMNs is surprisingly resistant to inhibition of energy metabolism and depletion of ATP, since concentrations of 2-dg that decreased ATP and other cell functions by more than 50% not only did not inhibit, but actually stimulated, CTX. These studies also indicate that the previously reported correlation between ATP depletion and CTX impairment observed in stored PMNs are not causally related.
Fluorescence cytophotometric analysis of megakaryocytic ploidy in culture: studies of normal and thrombocytopenic mice
Authors: Chatelain C , Burstein SA 
Published: October 2019

Abstract
A system for the accurate and rapid measurement of the ploidy of cultured megakaryocytes derived from megakaryocytic colony-forming cells (CFU-M) has been developed. Thirty thousand murine marrow cells per milliliter were cultured for varying time periods in agar in the presence of horse serum and pokeweed mitogen-stimulated spleen cell- conditioned medium (PWM-SCM). To ensure the inclusion of all the megakaryocytic cells in the analysis, entire agar discs were transferred onto glass slides and dried. Cells of the megakaryocytic lineage were identified by staining for acetylcholinesterase (AchE) for two hours. Subsequently, the nuclei of the cells were stained using 1.7 X 10(-5) mol/L chromomycin A3, a specific DNA-binding fluorochrome. Megakaryocytic colonies (greater than or equal to 2 AchE+ cells) were located under transmission light. The fluorescence emission of each cell of the colony was then measured by a photometer interfaced with a computer. The mean fluorescence emission of about 20 random granulocytes per slide was used as a 2N standard. There was no significant cell loss, quenching of fluorescence by AchE staining, or overlapping of colonies or cells. Approximately 100 megakaryocytes per hour could be analyzed. Modal ploidy of cultured megakaryocytes increased from 2N to 32N between days 3 and 6 in culture. Varying concentrations of PWM-SCM from 5% to 20% did not affect the ploidy distribution when examined at day 5. The heterogeneity of the ploidy of cells within colonies increased continuously with increasing cell numbers per colony. Clonal analyses of mean ploidy and ploidy heterogeneity did not show distinct types or classes of colonies; rather, the data show that megakaryocytic colonies are structured as a continuum. An inverse correlation was found between the number of cells constituting the colonies and their mean DNA content. To determine if short-term in vivo exposure of CFU-M to a thrombocytopenic environment could affect the ploidy of their progeny, mice were given rabbit antimouse-platelet serum while control animals were given normal rabbit serum. Twenty-four hours after injection, marrow derived from these animals was cultured. At day 5, the ploidy distributions and ploidy heterogeneity were identical in both treated and control groups. Thus, factor(s) that promote CFU-M proliferation do not affect megakaryocytic endoreduplication, while stimuli that acutely influence megakaryocytic ploidy in vivo do not determine the ultimate ploidy potential of megakaryocytes derived from a CFU-M.
Potentiation by red blood cells of shear-induced platelet aggregation: relative importance of chemical and physical mechanisms
Authors: Reimers RC , Sutera SP , Joist JH 
Published: October 2019

Abstract
Evidence has been reported to indicate that red blood cells (RBCs) may potentiate platelet adherence and platelet aggregation (PAG) in different flow systems in vitro as well as hemostatic platelet plug formation in response to vascular injury. In this study, we demonstrate that RBCs enhance PAG induced by well-defined, low-intensity, uniform, laminar shear stress. Potentiation by RBCs of shear-induced PAG was associated with appreciable loss of adenine nucleotides from 14C- adenine-labeled RBCs, the extent of which increased with increasing RBC concentration. The concentrations of RBC-derived ADP measured in the medium after shear, as determined by both high pressure liquid chromatography and the luciferin/luciferase system, were within the range of concentrations of ADP which may trigger PAG or potentiate PAG induced by low concentrations of other platelet agonists in the aggregometer. To assess the relative contribution of chemical (ADP) and physical (platelet surface transport) mechanisms in the RBC-mediated potentiation of shear-induced PAG, aliquots of citrated platelet-rich plasma (C-PRP) were exposed to shear stress in the presence of untreated RBCs or RBCs exposed to an antihemolytic concentration (5 mumol/L) of the membrane stabilizing agent, chlorpromazine (CPZ). Potentiation of shear-induced PAG in the RBC-CPZ system was significantly less than that in the untreated RBC system. However, CPZ- induced reduction of PAG potentiation was associated with an increase rather than a decrease in loss of adenine nucleotides from RBC. Furthermore, shear-induced PAG in C-PRP as well as ADP- and collagen- induced PAG in C-PRP in the aggregometer was significantly inhibited by 5 mumol/L CPZ, indicating that the observed reduced potentiation of shear-induced PAG by RBCs in the presence of CPZ was due to a direct inhibitory effect of the drug on platelets rather than a reduction of shear-induced liberation of ADP from RBCs. When aliquots of C-PRP were exposed to shear stress in the presence of RBCs completely depleted of ADP by fixation in 1% glutaraldehyde, potentiation of PAG was approximately half of that observed with intact RBCs. These findings indicate that both RBC-derived ADP and RBC-mediated platelet surface transport are involved in the potentiation by RBCs of PAG induced by laminar shear stress.
Red blood cell deformability influences platelets--vessel wall interaction in flowing blood
Authors: Aarts PA , Heethaar RM , Sixma JJ 
Published: October 2019

Abstract
Hematocrit and red cell size are important factors for the transport of blood platelets toward subendothelium in flowing blood. We report that red cell deformability also influences platelet transport. Red cell deformability was estimated with Couette-flow viscosimetry at a shear rate of 130 s-1 and expressed as a ‘T’ factor--a dimensionless parameter relating the relative viscosity and the hematocrit derived from the relationship: T = (1 - mu -0.4 rel)/H, where mu rel is the relative viscosity and H is the hematocrit. The normal value of T was within a narrow range (0.91 +/- 0.02). Treatment of normal red cells with isoxsuprine and chlorpromazine caused decreased rigidity and decreased T. Cholesterol loading and treatment with diamide increased rigidity and increased T. In vitro perfusion experiments in an annular perfusion system with everted human umbilical arteries were performed with perfusates to which such treated red blood cells were added to investigate their influence on platelet adherence to artery subendothelium. Platelet adherence was well correlated with red cell rigidity, with increased adherence at increased rigidity and vice versa. A change in T of 0.10 corresponded to a change in platelet adherence of approximately 50%. These effects were more pronounced at a wall shear rate of 1,800 s-1 than at 300 s-1.
Further characterization of platelet-type von Willebrand's disease in Japan
Authors: Takahashi H , Handa M , Watanabe K , Ando Y , Nagayama R , Hattori A , Shibata A , Federici AB , Ruggeri ZM , Zimmerman TS 
Published: October 2019

Abstract
We studied four patients who showed aggregation of platelets in platelet-rich plasma at lower concentrations of ristocetin than those required for normal platelet-rich plasma and who demonstrated an increased capacity of the platelets to bind normal von Willebrand factor. The four patients were from two Japanese families. Platelets from one family aggregated spontaneously in vitro, and platelets from both families aggregated upon the addition of normal plasma and cryoprecipitate, in the absence of ristocetin or other agonists. Analysis of the multimeric composition of von Willebrand factor by sodium dodecyl sulfate-agarose gel electrophoresis revealed a decrease in large multimers or a decrease in both large and intermediate multimers in plasma, but normal multimers in platelets. 1-Deamino-[8-D- arginine]-vasopressin caused by an immediate appearance of larger multimers in plasma, followed by the rapid disappearance of these multimers from circulating plasma. Analysis of platelet membrane glycoproteins from the patients showed that there were two distinct bands in the glycoprotein I region; one migrated in a slower region and the other in a faster region than normal glycoprotein Ib. We suggest that the platelet receptor abnormality in these patients is related to this abnormality of glycoprotein Ib.