bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteolysis of von Willebrand factor in therapeutic plasma concentrates
Authors: Mannuccio PM , Lattuada A , Ruggeri ZM 
Published: October 2019

Abstract
Therapeutic plasma concentrates containing vo Willebrand factor (vWF) lack the largest, most hemostatically active multimers. To evaluate whether this abnormality results from proteolysis during manufacturing, we have analyzed the subunit structure of vWF in several commercial products and found a marked reduction in the relative content of intact 225-kD subunit, paralleled by an increase in the proteolytic fragments normally present in plasma, particularly that of 176 kD. There was no heightened vWF fragmentation in blood-bank cryoprecipitate prepared from platelet-poor, single-donor plasma; in contrast, there was a marked degree of fragmentation in cryoprecipitate prepared from pooled plasmapheresis plasma representing the starting fraction for the production of commercial concentrates. In cryoprecipitate prepared experimentally from plasma containing varying numbers of platelets, the degradation of vWF was proportional to the platelet count, but was greatly diminished by adding protease inhibitors to the plasma. On the basis of these findings, we postulate that the loss of the largest vWF multimers in commercial products results from the use of poorly centrifuged plasmapheresis plasma containing an excessive number of residual platelets and leukocytes. These cells, lysing when plasma is frozen and thawed for the preparation of cryoprecipitate, may liberate proteolytic enzymes that cleave the vWF subunit and contribute to the degradation of the largest multimers. Our results should help devise new approaches for the preparation of more effective concentrates for the treatment of von Willebrand disease.
Bedside filtration of blood products in the prevention of HLA alloimmunization--a prospective randomized study. Alloimmunisation Study Group
Authors: Williamson LM , Wimperis JZ , Williamson P , Copplestone JA , Gooi HC , Morgenstern GR , Norfolk DR 
Published: October 2019

Abstract
To test the efficacy of poststorage bedside leucodepletion of blood products in the prevention of primary HLA alloimmunization and its clinical sequelae, 172 patients with hematologic malignancy requiring intensive red blood cell and platelet support were randomized to receive either standard or filtered red blood cells and platelets. Quality control of bedside filtration was explored by sequential sampling downstream of the filter, but this did not predict the total number of leucocytes transfused. After exclusions, 123 evaluable patients were assessed every two weeks until the end of therapy. HLA antibodies developed in 21 of 56 (37.5%) nonfilter (NF) and 15 of 67 (22%) filter (F) patients (risk ratio estimate, 0.60 [95% confidence interval, 0.34 to 1.05]; P = .07). Patients with acute myeloid leukemia (AML; n = 53) had higher alloimmunization rates in both arms of the study, with a greater effect of filtration (62.5% NF and 31.0% F; P = .025). Bedside filtration did not affect the overall incidence of febrile transfusion reactions (FTRs; 37% NF and 34% F; P = .71) or of platelet refractoriness assessed in 50 patients (30% NF and 26% F), despite an association between broad HLA reactivity and both FTRs and refractoriness. However, FTRs were also seen in 28 patients without HLA antibodies. Five alloimmunized refractory patients (2 F and 3 NF) required HLA-selected platelets. This report, the first prospective study of bedside filtration, has failed to show clear clinical benefit. Methodological limitations may account in part for this failure, notably the difficulties in accurately assessing the number of leucocytes transfused.
7E3 F(ab′)2 , a Monoclonal Antibody to the Platelet GPIIb/IIIa Receptor, Protects Against Microangiopathic Hemolytic Anemia and Microvascular Thrombotic Renal Failure in Baboons Treated With C4b Binding Protein and a Sublethal Infusion of Escherichia coli
Authors: Taylor F.B. , Coller B.S. , Chang A.C.K. , Peer G. , Jordan R. , Engellener W. , Esmon C.T. 
Published: October 2019

AbstractWe have used our previously described baboon model of infusion of both a sublethal dose of Escherichia coli and C4b binding protein to assess the impact of inhibiting platelet function with the F(ab′ )2 fragment of the monoclonal antibody 7E3, directed against the platelet glycoprotein (GP)IIb/IIIa receptor, on the characteristic microvascular changes. At a dose of 0.25 to 0.35 mg/kg bolus plus an infusion of 0.25 to 0.35 mg/kg over 6 hours, c7E3 F(ab′ )2 had only a minimal impact on fibrinogen consumption and delayed but did not prevent, the development of thrombocytopenia. Treatment with 7E3 F(ab′ )2 , however, produced significant protection from the development of microangiopathic hemolysis and renal insufficiency. Histologic examination supported these observations, with treated animals having fewer schistocytes on blood smear and less evidence of ischemic renal changes. Treated animals also had more rapid recovery of peripheral white blood counts, suggesting a possible protective effect of treatment on ischemic damage to the bone marrow. These data indicate that potent inhibition of platelet function via GPIIb/IIIa receptor blockade can decrease ischemic organ damage in this animal model that has features similar to those found in diffuse intravascular coagulation, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura.
Molecular Mechanisms of Monocyte Adhesion to Interleukin-1β–Stimulated Endothelial Cells Under Physiologic Flow Conditions
Authors: Kukreti Sharad , Konstantopoulos Konstantinos , Smith C. Wayne , McIntire Larry V. 
Published: October 2019

AbstractThis study identifies multiple pathways used by monocytes to adhere to 4-hour interleukin-1β stimulated human umbilical vein endothelial cells under flow conditions. Physiologic shear stresses were simulated in a flow chamber with parallel plate geometry; quantitation of primary adhesion, secondary adhesion, and transmigration was performed using phase contrast videomicroscopy. Neuraminidase treatment of monocytes reduced primary interaction by 50%, whereas blocking L-selectin or very late antigen-4 showed significant but smaller effects (∼30% inhibition). However, a combined treatment against all three pathways was able to reduce interaction by 80%. Blocking β2 and α4 integrin pathways together inhibited secondary/firm adhesion by 75%. Only 40% of firmly adherent monocytes transmigrated across the endothelial monolayer with significantly increased transmigration times when both β2 and α4 integrins were blocked. These results demonstrate that monocytes can use multiple receptors to interact with endothelial cells at both primary and secondary adhesion stages, and that these pathways have to be blocked simultaneously for maximum inhibition.
Differential Rates of Somatic Hypermutation in VH Genes Among Subsets of Chronic Lymphocytic Leukemia Defined by Chromosomal Abnormalities
Authors: Oscier David G. , Thompsett Andrew , Zhu Delin , Stevenson Freda K. 
Published: October 2019

AbstractChronic lymphocytic leukemia (CLL) is a B-cell tumor involving small lymphocytes that generally express the CD5 antigen and low levels of surface Ig. Within this definition, there is heterogeneity among cases in cell morphology, karyotypic abnormalities, and clinical course. Trisomy 12, the most frequent karyotypic abnormality, is commonly found in a subset of CLL with atypical morphology. It has also been associated with advanced disease, and possibly with a less favorable prognosis. A further subset of cases with abnormalities involving chromosome 13q14 have typical lymphocyte morphology. Occasionally, the two abnormalities are found together. To assess the clonal history of the cell of origin in disease subsets defined by these two chromosomal abnormalities, we investigated the usage of VH genes and the pattern of somatic mutation in 10 cases of trisomy 12 with atypical morphology and eight cases of 13q14 abnormality with typical morphology. In addition, four cases with both chromosomal abnormalities were analyzed. Results confirm a common usage of the VH1 family in all subsets. However, the patterns of somatic mutation were distinct, with cases of trisomy 12 showing a minimal level of mutation (mean ± SD, 0.34% ± 0.86%) and cases of 13q14 abnormality showing significant levels (6.5% ± 1.67%). The four cases with both abnormalities showed a mixed pattern. All mutated cases had intraclonal homogeneity, and three of 10 had a pattern indicative of antigen selection. These results suggest that the clonal history of the two subsets of CLL may differ.
Homozygous Deletion of the p16/MTS1 Gene in Pediatric Acute Lymphoblastic Leukemia Is Associated With Unfavorable Clinical Outcome
Authors: Kees Ursula R. , Burton Paul R. , Lü Changlong , Baker David L. 
Published: October 2019

Abstract
The p16 gene (MTS1, CDKN2, p16INK4A, CDKI) encoding an inhibitor of cyclin-dependent kinase 4 (cdk4) has been found to be deleted in various types of tumors, including leukemia, and is thought to code for a tumor suppressor gene. Our preliminary findings on eight pediatric patients with acute lymphoblastic leukemia (ALL) suggested that the survival of patients carrying a homozygous p16 gene deletion was significantly inferior to that of those without a deletion. The present study on 48 patients tested the hypothesis that the clinical outcome for pediatric ALL patients is correlated with the presence or absence of the p16 gene. Overall, nine of 48 children (18.3%) carried a homozygous p16 deletion. Such deletions were significantly more common (P = .003) among T-ALL patients (five of eight, 62.5%) than among precursor-B-ALL patients (four of 40, 10.0%). Of nine patients exhibiting p16 deletions, eight (88.9%) were classified as high-risk patients by the recognized prognostic factors of age, white blood cell count, and T-cell phenotype. The 4-year event-free survival in the study population as a whole was 72.7%. Without adjustment for other risk factors (univariate model), the presence of a homozygous p16 deletion was associated with a markedly increased probability of both relapse (P = .0003) and death (P = .002). These findings raise the question of whether the p16 deletion itself confers an increased risk of relapse after adjusting for the known risk factors. In this analysis, the estimated risk multiplier factor for relapse in patients carrying the p16 deletion was 14.0 (P = .0004) and for the risk of death 15.6 (P = .0008). We therefore conclude that the presence of a homozygous p16 deletion may well be an important risk factor for both relapse and death in childhood ALL, and that its prognostic effect is not a consequence of confounding by other factors already known to influence outcome in this disease.
Tissue Factor Pathway Inhibitor Blocks Cellular Effects of Endotoxin by Binding to Endotoxin and Interfering With Transfer to CD14
Authors: Park C. Thomas , Creasey Abla A. , Wright Samuel D. 
Published: October 2019

AbstractTissue factor pathway inhibitor (TFPI) is a Kunitz-type plasma protease inhibitor that inhibits factor Xa and the factor VIIa/tissue factor catalytic complex. It plays an important role in feedback inhibition of the coagulation cascade (Broze, Annu Rev Med 46:103, 1995). TFPI has also been used successfully to prevent lethality and attenuate coagulopathic responses in a baboon model of septic shock (Creasey et al, J Clin Invest 91:2850, 1993; and Carr et al, Circ Shock 44:126, 1995). However, the mechanism of reduced mortality in these animals could not be explained merely by the anticoagulant effect of TFPI, because TFPI-treated animals also had a significantly depressed interleukin-6 response. Moreover, inhibition of coagulopathic responses by other anticoagulants has failed to block the organ damage or lethal effect of endotoxic shock (Coalson et al, Circ Shock 5:423, 1978; Warr et al, Blood 75:1481, 1990; and Taylor et al, Blood 78:364, 1991). We show here that recombinant TFPI can bind to endotoxin in vitro. This binding prevents interaction of endotoxin with both lipopolysaccharide binding protein and CD14, thereby blocking cellular responses.
The Suprapharmacologic Dosing of Antithrombin Concentrate for Staphylococcus Aureus-Induced Disseminated Intravascular Coagulation in Guinea Pigs: Substantial Reduction in Mortality and Morbidity
Authors: Kessler Craig M. , Tang ZhaoCheng , Jacobs Helena M. , Szymanski Linda M. 
Published: October 2019

AbstractAn animal model of gram-positive septicemia was developed to evaluate the effects of antithrombin (AT) concentrates on morbidity, mortality, and laboratory consequences of disseminated intravascular coagulation (DIC). DIC was induced in guinea pigs by infusing Staphylococcus aureus (SA) isolated from blood cultures of patients with DIC (DIC-SA) or without DIC (non–DIC-SA). The non–DIC-SA animals and animals infused with sterile saline served as controls. Varying doses of AT were administered either 30 minutes or 24 hours after infusion of SA. DIC was confirmed within 4 hours by changes in prothrombin time, activated partial thromboplastin time, fibrinogen, fibrinogen-fibrin degradation products, and AT activity. Clinical bleeding was also evident. Mortality of untreated DIC-SA animals was 36% within 24 hours and up to 75% by 72 hours. Intervention with any dose of AT between 125 and 1,000 IU/kg 30 minutes after DIC-SA infusion was associated with 100% survival (P ≤ .05 in the 250 IU/kg group) and sustained increases in AT activity and fibrinogen concentrations (P ≤ .05). When AT was administered in combination with low molecular weight heparin (LMWH) or if LMWH was adminstered alone, mortality from DIC-SA was slightly, but not significantly reduced compared with untreated DIC-SA. Gross hemorrhage was observed premortem and at autopsy in all of the DIC-SA animals but in substantially fewer animals that received AT (P ≤ .001 in the 250, 500, and 1,000 IU/kg groups). In contrast, groups treated with LMWH, alone or with AT, experienced hemorrhage and appeared to develop pathologic DIC. Fibrin formation in end-organs was detected in all guinea pigs in the untreated DIC-SA group and in the groups treated with 125 IU/kg AT and LMWH alone. AT doses between 250 and 1,000 IU/kg administered 30 minutes after DIC-SA infusion prevented fibrin formation in end-organs (P ≤ .001 in the 250 and 1,000 IU/kg groups). AT administered 24 hours after DIC-SA could not reverse pre-existing histopathologic evidence of DIC but favorably affected survival, which reached statistical significance in the 1,000 IU/kg AT group (P ≤ .025). In summary, suprapharmacologic doses of AT concentrate significantly decreased morbidity and mortality and ameliorated adverse changes in laboratory measures induced by DIC-SA in this guinea pig model and were not associated with untoward hemorrhagic complications. These findings provide justification for studying the use of AT therapy in patients with DIC-SA.
Mechanisms of Stroke in Sickle Cell Disease: Sickle Erythrocytes Decrease Cerebral Blood Flow in Rats After Nitric Oxide Synthase Inhibition
Authors: French James A. , Kenny Dermot , Scott J. Paul , Hoffmann Raymond G. , Wood James D. , Hudetz Antal G. , Hillery Cheryl A. 
Published: October 2019

AbstractThe etiology of stroke in sickle cell disease is unclear, but may involve abnormal red blood cell (RBC) adhesion to the vascular endothelium and altered vasomotor tone regulation. Therefore, we examined both the adhesion of sickle (SS)-RBCs to cerebral microvessels and the effect of SS-RBCs on cerebral blood flow when the nitric oxide (NO) pathway was inhibited. The effect of SS-RBCs was studied in the rat cerebral microcirculation using either a cranial window for direct visualization of infused RBCs or laser Doppler flowmetry (LDF ) to measure RBC flow. When fluorescently labeled human RBCs were infused into rats, SS-RBCs had increased adhesion to rat cerebral microvessels compared with control AA-RBCs (P = .01). Next, washed SS-RBCs or AA-RBCs were infused into rats prepared with LDF probes after pretreatment (40 mg/kg intravenously) with the NO synthase inhibitor, N-ω-nitro-L-arginine methyl ester (L-NAME), or the control isomer, D-NAME. In 9 rats treated with systemic L-NAME and SS-RBCs, 5 of 9 experienced a significant decrease in LDF and died within 30 minutes after the RBC infusion (P = .0012). In contrast, all control groups completed the experiment with stable LDF and hemodynamics. Four rats received a localized superfusion of L-NAME (1 mmol/L) through the cranial window followed by infusion of SS-RBCs. Total cessation of flow in all observed cerebral microvessels occurred in 3 of 4 rats within 15 minutes after infusion of SS-RBCs. We conclude that the NO pathway is critical in maintaining cerebral blood flow in the presence of SS-RBCs in this rat model. In addition, the enhanced adhesion of SS-RBCs to rat brain microvessels may contribute to cerebral vaso-occlusion either directly, by disrupting blood flow, or indirectly, by disturbing the vascular endothelium.
Expression of the T-Cell Activation Antigen, OX-40, Identifies Alloreactive T Cells in Acute Graft-Versus-Host Disease
Authors: Tittle Thomas V. , Weinberg Andrew D. , Steinkeler Cara N. , Maziarz Richard T. 
Published: October 2019

AbstractThe OX-40 molecule is expressed on the surface of recently activated T lymphocytes. The presence of OX-40 on CD4+ T cells was analyzed in a rat haplo-identical (parental → F1) bone marrow transplant model of acute graft-versus-host disease (aGVHD). Increased numbers of activated CD4+ T cells that expressed the OX-40 antigen were detected in peripheral blood soon after transplantation before the earliest sign of disease. The peak of OX-40 expression occurred 12 days posttransplantation with a range of 18% to 36% of circulating T cells and remained 10-fold above background, never returning to baseline. A slight increase in OX-40 expression (range, 1% to 6%) was also detected on peripheral blood lymphocytes from control syngeneic F1 → F1 recipients. OX-40+ T cells were isolated from spleen, skin, lymph node, and liver tissue of rats undergoing aGVHD, but not in syngeneic transplants. OX-40+ T cells isolated from these tissues were of donor origin and were shown to be allo-reactive. These data raise the possibility of using the OX-40 antibody to detect and deplete selectively the T cells that cause aGVHD.
Altered Myeloid Development and Acute Leukemia in Transgenic Mice Expressing PML-RARα Under Control of Cathepsin G Regulatory Sequences
Authors: Grisolano Jay L. , Wesselschmidt Robin L. , Pelicci Pier Giuseppe , Ley Timothy J. 
Published: October 2019

AbstractAcute promyelocytic leukemia (APML) is characterized by abnormal myeloid development, resulting an accumulation of leukemic promyelocytes that are often highly sensitive to retinoic acid. A balanced t(15; 17) (q22; q21) reciprocal chromosomal translocation is found in approximately 90% of APML patients; this translocation fuses the PML gene on chromosome 15 to the retinoic acid receptor α (RARα) gene on chromosome 17, creating two novel fusion genes, PML-RARα and RARα-PML. The PML-RARα fusion gene product, which is expressed in virtually all patients with t(15; 17), is thought to play a direct role in the pathogenesis of APML. To determine whether PML-RARα is sufficient to cause APML in an animal model, we used the promyelocyte-specific targeting sequences of the human cathepsin G (hCG) gene to direct the expression of a PML-RARα cDNA to the early myeloid cells of transgenic mice. Mice expressing the hCG–PML-RARα transgene were found to have altered myeloid development that was characterized by increased percentages of immature and mature myeloid cells in the peripheral blood, bone marrow, and spleen. In addition, approximately 30% of transgene-expressing mice eventually developed acute myeloid leukemia after a long latent period. The splenic promyelocytes of mice with both the nonleukemic and leukemic phenotypes responded to all-trans retinoic acid (ATRA) treatment, which caused apoptosis of myeloid precursors. Although low-level expression of the hCG–PML-RARα transgene is not sufficient to directly cause acute myeloid leukemia in mice, its expression alters myeloid development, resulting in an accumulation of myeloid precursors that may be susceptible to cooperative transforming events.
Interactions Between c-kit and Stem Cell Factor Are Not Required for B-Cell Development In Vivo
Authors: Takeda Shunichi , Shimizu Takeyuki , Rodewald Hans-Reimer 
Published: October 2019

AbstractThe receptor-type tyrosine kinase, c-kit is expressed in hematopoietic stem cells (HSC), myeloid, and lymphoid precursors. In c-kit ligand-deficient mice, absolute numbers of HSC are mildly reduced suggesting that c-kit is not essential for HSC development. However, c-kit− HSC cannot form spleen colonies or reconstitute hematopoietic functions in lethally irradiated recipient mice. Based on in in vitro experiments, a critical role of c-kit in B-cell development was suggested. Here we have investigated the B-cell development of c-kitnull mutant (W/W ) mice in vivo. Furthermore, day 13 fetal liver cells from wild type or W/W mice were transferred into immunodeficient RAG-2−/− mice. Surprisingly, transferred c-kit− cells gave rise to all stages of immature B cells in the bone marrow and subsequently to mature conventional B2, as well as B1, type B cells in the recipients to the same extent as transferred wild type cells. Hence, in contrast to important roles of c-kit in the expansion of HSC and the generation of erythroid and myeloid lineages and T-cell precursors, c-kit− HSC can colonize the recipient bone marrow and differentiate into B cells in the absence of c-kit.
Activation of JAK2 in Human Vascular Endothelial Cells by Granulocyte-Macrophage Colony-Stimulating Factor
Authors: Soldi Raffaella , Primo Luca , Brizzi Maria Felice , Sanavio Fiorella , Aglietta Massimo , Polentarutti Nadia , Pegoraro Luigi , Mantovani Alberto , Bussolino Federico 
Published: October 2019

AbstractBesides the regulation of hematopoiesis, granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the expression of a functional program in endothelial cells (ECs) related to angiogenesis and to their survival in the bone marrow microenvironment. ECs express specific GM-CSF high-affinity binding sites, which mediate the proliferative and migratory response. We now report that ECs express the α and β subunits of GM-CSF receptor (GM-CSFR), and that GM-CSF is able to activate the Janus kinase (JAK)2, a member of the cytosolic tyrosine kinase family, which is known to mediate signals of several non–tyrosine kinase receptors. JAK2 tyrosine phoshorylation, as well as activation of its catalytic activity, is induced by subnanomolar concentrations of GM-CSF and occurs within 3 minutes of stimulation and persists at least for 10 minutes. The effect is specific as inferred by the lack of effect of heat-inactivated GM-CSF or neutralized by specific antibodies and by the finding that interleukin-5, which utilizes a specific α chain and the same β chain of GM-CSFR, does not phosphorylate JAK2. Furthermore, we show that the amount of JAK2 physically associated with GM-CSFR β chain is increased after GM-CSF stimulation and that GM-CSF triggers both β chain and JAK2 tyrosine phosphorylation. Taken together, these results suggest that biologic activities of GM-CSF in vascular endothelium may, in part, be elicited by GM-CSFR–mediated JAK2 activation.