bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunocytochemical localization of fibrinogen during thrombin-induced aggregation of washed human platelets
Authors: Suzuki H , Kinlough-Rathbone RL , Packham MA , Tanoue K , Yamazaki H , Mustard JF 
Published: October 2019

Abstract
Because thrombin aggregates afibrinogenemic platelets and platelets from patients with the gray platelet syndrome and because antibodies to fibrinogen inhibit thrombin-induced aggregation only at low concentrations of thrombin, the role of fibrinogen in the formation of thrombin-induced aggregates was investigated further with human platelets washed and resuspended in Tyrode-albumin solution containing apyrase, either with or without added Ca2+ (2 mmol/L). Samples for immunocytochemical assessment of fibrinogen distribution were taken at several times (up to five minutes) after aggregation induced by 0.5 U/mL of thrombin. Glutaraldehyde-fixed samples were embedded in Lowicryl K4M, sectioned, incubated with goat antihuman fibrinogen, washed, reacted with gold-labeled antigoat IgG, and prepared for electron microscopy. By 10 seconds, small aggregates formed, and granules were centralized; alpha granules were heavily labeled with immunogold, but the platelet surface was not. As large aggregates formed, granule swelling or fusion occurred, and in some areas granule material seemed to be in contact with the exterior. In these experiments with no added fibrinogen, there were some clusters of gold particles on the platelet surfaces remote from sites of granule discharge, but there were large areas where platelets were in close contact with little or no fibrinogen detectable between them. No fibrin was visible up to five minutes after the addition of thrombin, which indicated that fibrinogen from the granules does not readily become available for fibrin formation in the ambient fluid. Similar results were obtained in media with and without added Ca2+. Thus at least some aggregation in response to thrombin can occur without the participation of released fibrinogen, and much of the granule fibrinogen appears to remain localized at sites where granules fuse with the plasma membrane or the open canalicular system. Incubation of unstirred samples with thrombin for ten minutes resulted in the formation of small aggregates, extensive gold label in regions connected to the exterior of the platelets, but very little gold labeling of the platelet membrane and no visible fibrin formation. When the platelets were aggregated in the presence of external fibrinogen, the morphological changes within the platelets were the same, but fibrinogen rapidly became associated with the entire platelet surface, and visible fibrin formed within 30 seconds in the medium containing 2 mmol/L Ca2+.(ABSTRACT TRUNCATED AT 400 WORDS).
Analysis of von Willebrand factor mRNA from the lung of pigs with severe von Willebrand disease by using a human cDNA probe
Authors: Wu QY , Bahnak BR , Coulombel L , Kerbiriou-Nabias D , Drouet L , Pietu G , Meulien P , Pavirani A , Caen JP , Meyer D 
Published: October 2019

Abstract
To examine the control of porcine von Willebrand factor (vWF) biosynthesis we cloned human vWF complementary DNA (cDNA) and investigated the expression of the vWF gene in lungs from normal pigs and pigs with severe von Willebrand's disease (vWD). Recombinant clones spanning approximately 90% of human vWF cDNA were identified in a lambda gt10 human lung cDNA library by screening with oligonucleotides. One clone spanning nucleotides 960 to 3,240 of human vWF cDNA was used to investigate the steady-state levels of vWF mRNA in lungs from normal pigs and from pigs phenotypically determined to be homozygous for vWD. This clone hybridized with genomic DNA from pig leukocytes when Southern blots were processed under very stringent conditions; therefore, human cDNA clones were considered valid probes to detect porcine mRNA. Northern blot analysis of total RNA from normal pig lung and human umbilical vein endothelial cells identified the vWF mRNA as a molecular species of approximately 9.0 kilobases (kb). A very faint to undetectable band at 9.0 kb in total RNA from lungs of vWD pigs suggested a decreased rate of transcription of the vWF gene. Sucrose density gradient centrifugation of RNA from the vWD pigs confirmed by Northern analysis that the high-molecular weight fractions contained vWF mRNA and at the same size as normal pig mRNA. Dot blot hybridization analysis of vWF and actin mRNA processed under stringent conditions demonstrated that the relative ratio of vWF mRNA to actin mRNA in the vWD pigs varied from 21% to 41% of the ratio observed in normal pigs. Because the amount of vWF mRNA is not correlated to the amount of vWF activity or antigen in plasma of vWD pigs we conclude that posttranscriptional events are also probably involved in abnormal expression of vWF in these animals.
A simple approach to prenatal diagnosis of beta-thalassemia in a geographic area where multiple mutations occur
Authors: Cai SP , Zhang JZ , Huang DH , Wang ZX , Kan YW 
Published: October 2019

Abstract
We describe a simple approach for detecting beta-thalassemia mutations in geographic areas such as southern China where multiple mutations are known to occur. Segments of the beta-globin gene were amplified in vitro by using the polymerase chain reaction. Dot blot hybridization of the amplified DNA with oligonucleotide probes corresponding to the six mutations found in southern China could directly identify the mutations causing beta-thalassemia in the affected families. The increased number of target sequences after amplification allows the use of 35S-labeled probes, which are reusable for up to 3 months. The mutations can be determined in two days.
Hereditary poikilocytic anemia associated with the co-inheritance of two alpha spectrin abnormalities
Authors: Iarocci TA , Wagner GM , Mohandas N , Lane PA , Mentzer WC 
Published: October 2019

Abstract
This report describes a black family in which two distinct structural defects of alpha spectrin were inherited singly and in combination. The propositus, who has a poikilocytic hemolytic anemia that shares many of the features of hereditary pyropoikilocytosis (HPP) or homozygous elliptocytosis, is a compound heterozygote for both the spectrin alpha 1/65 and spectrin alpha 1/50a defects as demonstrated by electrophoretic analysis of spectrin tryptic fragments. The spectrin alpha 1/65 defect alone was found in his mother and sibling, while the spectrin alpha 1/50a defect was present in the father and another sibling. The red cell spectrin content was normal in all family members. The functional consequences of inheritance of these two spectrin defects were compared with those found in an unrelated patient with classic HPP who had the alpha 1/50a spectrin defect and was spectrin deficient as well. Prolonged incubation at 37 degrees C resulted in striking budding, fragmentation, and sphering of classic HPP red cells but only minimal changes in propositus cells. The percentage of spectrin dimers was increased tenfold in classic HPP, sevenfold in the propositus, and threefold in other family members. Mechanical stability of erythrocyte ghosts, measured by ektacytometry, was reduced severely in both classic HPP and in the propositus, but only moderately in other family members. Thus, co-inheritance of two alpha spectrin defects can result in a poikilocytic hemolytic anemia milder than that usually found in HPP. The greater clinical severity of HPP may be a consequence of the presence of spectrin deficiency, a finding absent in the propositus.
Prevention of refractoriness and HLA-alloimmunization using filtered blood products
Authors: Sniecinski I , O'Donnell MR , Nowicki B , Hill LR 
Published: October 2019

Abstract
Depletion of leukocytes from all blood products may decrease the incidence of alloimmunization to HLA antigens present on the white cells and thus delay the onset of refractoriness to random donor platelet support. In order to test this hypothesis, 54 patients with hematologic malignancy or marrow aplasia were entered on a prospective randomized trial using cotton-wool filtration as a method of leukocyte depletion of red cell and platelet concentrates. Forty patients were considered evaluable; 20 patients received filtered products and 20 patients in the control group received standard unfiltered products. The filter was 99% efficient in removal of leukocytes (average number of WBC/platelet product, 6 X 10(6)). Platelet loss by this technique was 8%. Alloimmunization was assessed by detection of de novo formed lymphocytotoxic and platelet specific antibodies by microcytotoxicity test, Staph A protein radioimmunoassay, and solid phase red cell adherence test. In the group receiving filtered products, three of 20 (15%) patients developed lymphocytotoxic antibodies while ten of 20 (50%) patients in the control group developed cytotoxic antibodies (P = .01 by actuarial methods). Platelet antibodies were detected in seven of ten alloimmunized patients in the control group and three of three patients in the study group. Clinical evidence of refractoriness was seen in three of 20 patients in the filtered group and ten of 20 in the control group (P = .01 by actuarial methods). The cost of filtration was a fraction of the cost of a plateletpheresis product. Filtration appears to be an effective and economical method for reducing alloimmunization and clinical refractoriness to random donor platelets in patient receiving long-term transfusion support.
The relationship between in vivo generated hemoglobin skeletal protein complex and increased red cell membrane rigidity
Authors: Fortier N , Snyder LM , Garver F , Kiefer C , McKenney J , Mohandas N 
Published: October 2019

Abstract
In vitro induced oxidative damage to normal human RBCs has previously been shown to result in increased membrane rigidity as a consequence of the generation of a protein complex between hemoglobin and spectrin. In order to determine if in vivo generated hemoglobin-spectrin complexes may play a role in increased membrane rigidity of certain pathologic red cells, we measured both these parameters in membranes prepared from hereditary xerocytosis (Hx), sickle cell disease (Sc), and red cells from thalassemia minor (beta thal). Membranes were prepared from density-fractionated red cells, and membrane deformability was measured using an ektacytometer. Hemoglobin-spectrin complex was determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel analysis, as well as by Western blot analysis using a monoclonal antibody against the beta- subunit of hemoglobin. For these three types of pathologic red cells, progressive cellular dehydration was associated with increased membrane rigidity and increased content of hemoglobin-spectrin complex. Moreover, the increase in membrane rigidity appeared to be directly related to the quantity of hemoglobin-spectrin complex associated with the membrane. Our findings imply that hemoglobin-spectrin complex is generated in vivo, and this in turn results in increased membrane rigidity of certain pathologic red cells. The data further suggest that oxidative crosslinking may play an important role in the pathophysiology of certain red cell disorders.
Cellular and molecular studies on infant null acute lymphoblastic leukemia
Authors: Katz F , Malcolm S , Gibbons B , Tilly R , Lam G , Robertson ME , Czepulkowski B , Chessells J 
Published: October 2019

Abstract
We have studied the cellular and molecular basis of eight cases of infant null acute lymphoblastic leukemia (ALL). All eight patients were under 9 months of age and presented with leukocyte counts in excess of 60 X 10(9)/L, organomegaly, and in two cases CNS infiltration. Although seven cases were morphologically classified as ALL, one patient had both lymphoid and myeloid features. Phenotypic analysis of leukemic blasts from all patients showed a typical null ALL pattern, ie, CD10 (common ALL antigen)-negative, strongly HLA-DR-positive, and CD19 (B4)- positive. The presence of terminal deoxynucleotidyl transferase (TdT) at presentation was positive in six patients' cells and negative in two. Two patients also expressed the myeloid-associated markers CD33 (MY9) and CD15 (TG1), and coexpression of CD19 and CD33 was confirmed in these two by using dual marker flow cytometry (fluorescence- activated cell sorting). Electron microscopic examination of the same two patients' cells showed the presence of monocytoid blasts that labeled with the pan-B cell antibody B4 (CD19). Short-term culture of one of these patients cells in the presence of phorbol ester resulted in the majority of the cells exhibiting myeloid markers, strong nonspecific esterase positivity, and phagocytic properties. Cytogenetic analysis showed the common feature in 7 of 8 cases to be a break in band 11q23. Molecular analysis of DNA from the blast cells of all eight patients showed rearrangement of the immunoglobulin heavy-chain genes in all cases without, however, any evidence of kappa light-chain rearrangement. T cell receptor genes were present in the germline configuration in all cases. Rearrangements of the c-ets 1 oncogene, which maps to band 11q23, were not detected, thus providing no evidence for involvement of this oncogene in the common disease process. Our data indicate that although infant null ALL may present as a heterogeneous disease the similarity of many features between cases suggests a common derivation from a precursor cell sharing phenotypic and genotypic features of both B and myeloid progenitor cells.
Lymphocyte aggregation in response to adrenergic stimulation
Authors: Hammerschmidt DE , Jeanneret C , Husak M , Lobell M , Jacob HS 
Published: October 2019

Abstract
A nonanemic chronic lymphocytic leukemia patient with nearly 500,000 lymphocytes/microL underwent leukapheresis when she presented with CNS symptoms and retinal vascular engorgement. Respiratory distress developed during the cell separator run, which led us to ask whether the procedure could have changed the adhesive properties of her cells. C5a desarginine, N-f-Met-Leu-Phe, adenosine diphosphate, and collagen all failed to aggregate her lymphocytes in vitro, but arachidonic acid, excess free calcium, and 4 mumol/L epinephrine did aggregate the cells. Arachidonate-induced aggregation appeared to be a toxic phenomenon: the ED50 for aggregation was statistically indistinguishable from that for cytotoxicity, and aspirin only mildly blunted the response. In contrast, epinephrine-induced aggregation was not associated with lactic dehydrogenase release or the loss of trypan blue exclusion and was blunted by propranolol; radiopindolol-binding studies confirmed the presence of a beta-adrenergic receptor. There were approximately 3,000 receptors/cell, with no statistically significant difference between normal and chronic lymphocytic leukemia B cells or between B cells and T cells (separated by rosetting techniques). The Kd for the B cells' receptor, however, was less than that for T cells by a factor of ten (P less than .01). We conclude that B cells may aggregate when stimulated and that they--like T cells--have beta-adrenergic receptors. Adrenergically mediated changes in B cell adhesiveness may play a role in regulating lymphocyte traffic; in the rare patient with truly enormous B cell counts, we postulate that they may be an occasional cause of morbidity.
Modulation of nitrosourea resistance in myeloid leukemias
Authors: Gerson SL , Trey JE 
Published: October 2019

Abstract
Drug resistance in myeloid leukemias may be mediated by an increased capacity to repair chemotherapy-induced DNA damage. Some tumor cell lines that are resistant to nitrosoureas contain the DNA repair protein O6-alkylguanine-DNA alkyltransferase (alkyltransferase). This protects cells by removing cytotoxic, nitrosourea-induced O6-alkylguanine adducts. We measured the level of alkyltransferase activity in myeloid leukemic cells freshly obtained from patients to determine whether the alkyltransferase was an important factor in nitrosourea resistance in these cells and whether inactivation of this protein could sensitize leukemic cells to nitrosoureas. Myeloid leukemic cells from patients with acute nonlymphocytic leukemia and chronic myelogenous leukemia had higher levels of alkyltransferase than did myeloid precursors from normal donors (P less than .01). This difference did not appear to be due to the state of differentiation of the leukemic or normal cells. To show that this repair protein mediated nitrosourea resistance in leukemic cells, cells were treated with the modified base O6- methylguanine to selectively and irreversibly inactivate the alkyltransferase and then exposed to 1,3-bis (2-chloroethyl)-1- nitrosourea (BCNU). An 18-hour incubation in 0.5 mmol/L O6- methylguanine caused an 87% +/- 3.6% decrease in alkyltransferase activity in leukemic cells and a 73% +/- 8.6% decrease in normal myeloid precursors. After treatment with O6-methylguanine, clonogenic leukemic cells from ten different donors became much more sensitive to BCNU, with a decrease in the dose needed to reduce colony survival by 50% (LD50) of 6.3 +/- 1.4-fold. A lesser effect was seen on CFU-GM, BFU- E, and CFU-GEM where the LD50 decreased two- to threefold. These studies show that nitrosourea resistance in myeloid leukemic cells can be abrogated by inactivation of the DNA repair protein O6-alkylguanine- DNA alkyltransferase. This method of biochemical modulation of DNA repair will sensitize leukemic cells to nitrosoureas in vitro and has the potential of increasing the therapeutic index of nitrosoureas in this disease.
Gamma-interferon modulates human monocyte/macrophage transferrin receptor expression
Authors: Taetle R , Honeysett JM 
Published: October 2019

Abstract
Although circulating human monocytes do not express transferrin (Tf) receptors, cultured adherent blood cells display high-affinity Tf binding sites. In the present studies, effects of various cytokines and biologically active proteins on human monocyte/macrophage Tf receptors were investigated. After culture, Tf receptor expression by adherent blood cells was time dependent and plateaued by 7 days. The addition of interleukin-1 (IL-1), alpha-interferon (alpha-IFN), granulocyte/macrophage-colony stimulating factor (GM-CSF), or human IgG to macrophages cultured for 4 days did not alter Tf receptor expression. Fe-saturated, human Tf caused a significant, dose-dependent decrease in receptor expression. At a dose of 100 U/mL, gamma- interferon (gamma-IFN) significantly increased Tf receptor expression by macrophages cultured for 4 (230% +/- 51% of control) or 7 days (150% +/- 22%). Scatchard analyses showed increased binding sites but no change in receptor affinity. Northern and slot blot analysis of cellular mRNA from macrophages cultured for 4 to 7 days and exposed to gamma-IFN showed a two- to fivefold increase in Tf receptor mRNA, but less than or equal to 30% increase in beta-actin mRNA. Ferritin content of gamma-IFN-treated macrophages was 47% to 63% of control cells. Net uptake of 59Fe from Tf by gamma-IFN-treated cells was 10% to 17% of control, but uptake of radiolabeled Tf was comparable. When macrophages were labeled with 59Fe and then exposed to gamma-IFN, cell-associated Fe was reduced by 43%, indicating that gamma-IFN caused macrophage Fe release. gamma-IFN specifically modulates Tf receptor display by inducing Fe release and reducing cellular Fe content. Regulation of Tf receptor expression in macrophages is controlled by cellular Fe content and is thus similar to regulatory mechanisms in dividing cells.
2',3'-Dideoxyadenosine is selectively toxic for TdT-positive cells
Authors: Spigelman Z , Duff R , Beardsley GP , Broder S , Cooney D , Landau NR , Mitsuya H , Ullman B , McCaffrey R 
Published: October 2019

Abstract
The 2′,3′-dideoxynucleosides (ddNs) are currently undergoing clinical evaluation as antiretroviral agents in HIV-infected individuals. When phosphorylated, the ddNs (ddNTPs) function as chain-terminating substrate analogues with reverse transcriptase, thereby inhibiting HIV replication. These nucleoside analogues can also inhibit, by chain- terminating additions, the primitive lymphoid DNA polymerase, terminal deoxynucleotidyl transferase (TdT). To determine the effect of possible intracellular chain-terminating additions of ddNMPs by TdT, we exposed a series of TdT-positive and TdT-negative cell lines to 2′,3′- dideoxyadenosine (ddA), a representative ddN. At ddA concentrations 25- fold higher than required for inhibition of HIV replication, progressive dose-related cytotoxicity was observed in the TdT-positive cell lines. This was accentuated by the adenosine deaminase inhibitor Coformycin (CF), presumably by enhancing the intracellular generation of ddATP from ddA. A central role of TdT in mediating the ddA/CF cytotoxicity was suggested by studies in a pre-B-cell line rendered TdT positive by infection with a TdT cDNA-containing retroviral vector. After a 48-hour continuous exposure period to 250 mumol/L ddA and 30 mumol/L CF, 30% cell death was observed in the TdT-negative parental line, whereas 90% cell death was observed in the TdT-positive daughter line. Exposure of fresh TdT-positive leukemic cells to ddA/CF for 72 hours ex vivo resulted in cytotoxicity (six cases of acute lymphocytic leukemia [ALL]) while not affecting TdT-negative acute leukemic cells (six cases). We conclude that ddA/CF selectively damages TdT-positive cells, presumably by chain-terminating additions of ddAMP, and that this may have therapeutic relevance in TdT-positive malignant disease.
Biochemical characterization and purification of HILDA, a human lymphokine active on eosinophils and bone marrow cells
Authors: Godard A , Gascan H , Naulet J , Peyrat MA , Jacques Y , Soulillou JP , Moreau JF 
Published: October 2019

Abstract
We previously described a lymphokine termed HILDA (for human interleukin DA) produced by T-lymphocyte alloreactive clones after antigenic stimulation. This factor sustains the growth of a murine IL3- sensitive cell line (DA2). In addition, HILDA is a potent activator of eosinophils and displays a burst-promoting activity on human bone marrow. In the present study, HILDA was purified to homogeneity from T- cell clone supernatant using successively sequential concentration, concanavalin A (ConA) affinity chromatography with differential elution (alpha-D glucopyranoside and alpha-D mannopyranoside), high-performance liquid chromatography (HPLC) gel filtration and reverse-phase HPLC. The pure material appeared as a 38-kd glycoprotein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing or nonreducing conditions. Biologic activity could be recovered from SDS- PAGE gel slices corresponding to the 38-kd band. We conclude from the specificity of the DA-2 cell line and biochemical characteristics described that this lymphokine is different from other known factors produced by human T lymphocytes.