bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased Risk of Cerebrovascular Events Is Associated with Elevated Factor XI Activity.
Authors: Yang David T. , Flanders Michele M. , Rodgers George M. 
Published: April 2020

Abstract
High levels of factor XI as measured by antigenic methods have been implicated as a risk factor for deep venous thrombosis, and there is limited evidence that increased factor XI activity as measured by a functional assay is associated with cardiovascular disease. In the current study, we evaluated factor XI antigen, factor XI functional activity and high-sensitivity C-reactive protein (hs-CRP) from 123 patients under the age of 55 with normal prothrombin and partial thromboplastin times undergoing evaluation for a hypercoagulable state. Of the 123 patients, 80 had a history suggestive of arterial thrombosis (65 with stroke symptoms, 13 with transient ischemic attack symptoms, and 2 with other arterial thrombi), 17 had a history of venous thrombosis, and 26 had indeterminate histories for arterial or venous thrombosis. 40 age- matched healthy subjects were used to determine the upper limit of normal for factor XI activity as defined by the 95th percentile value (141%). 17/80 (21%) of patients with arterial thrombosis and 3/17 (18%) of the patients with venous thrombosis had above normal factor XI activity levels. Based on this, those with elevated factor XI activity have a relative risk of 5.3 for a cerebrovascular event. Regression analysis demonstrates that factor XI activity appears to correlate with factor XI antigen level (slope=0.79 and R=0.67), but there is no correlation between factor XI activity or factor XI antigen levels and hs-CRP (R= −.003 and R=.096 respectively). Our findings suggest that elevated factor XI activity is associated with an increased risk for cerebrovascular events and confirms that elevated factor XI levels are also associated with increased risk for venous thrombosis. In addition, assessment of factor XI levels by two methods, both functional activity and antigenic level, appear to correlate with one another to a fair degree suggesting that increased activity is likely related to increased levels of the protein itself. Lastly, lack of correlation with hs-CRP suggests that factor XI is not an acute-phase reactant.
Population Characteristics n Mean Age Median Age Range Male:Female Normals 40 39±9 41 23–55 15:25 Arterial Thrombosis 80 42±8 43 20–55 36:44 Venous Thrombosis 17 38±11 37 20–54 7:10 Factor XI ActivityLevels Normal Arterial Thrombosis Venous Thrombosis Factor XI Activity (%) Mean±SD 101±23 136±111 111±36 Median 100 117 113 Range 57–155 55–675 71–196 95th percentile 141 # Cases above 95th percentile 2/40 (5%) 17/80 (21.3%) 3/17 (17.6%)
Evidence for a Novel Splice Variant of the Gene for Platelet Activating Factor Acetylhydrolase 1B2 (PAFAH1B2), an Important Signal Terminator in the Platelet Activating Factor (PAF) Pathway.
Authors: Olson Nels , Scott Bruce , Long George , Bovill Edwin 
Published: April 2020

Abstract
Introduction: A genome-wide scan of linkage with venous thrombosis in a thrombophilic kindred with type I protein C deficiency identified a candidate region on chromosome 11q23 (P&lt;0.0001). Located at the linkage peak is PAFAH1B2, the β-subunit of the intracellular form of PAFAH. Intracellular PAFAH is a heterodimer of alpha and beta subunits both of which have catalytic activity. PAFAH reduces intracellular PAF levels and a reduction in active PAFAH likely leads to an enhanced inflammatory response at the vascular wall. Resequencing experiments revealed a novel splice variant for the intracellular form of PAFAH. The current study characterizes this novel splice variant that results in the deletion of exon 6 and its catalytic domain and the introduction of an alternative 7th exon.
Methods: Identification of novel mRNA splice variants was achieved by sequencing PCR products obtained from amplifying known regions of PAFAH 1B2 mRNA. Confirmation of the exon 5 to 7 splice and exon 7 polyadenylation were obtained from sequencing 3′RACE products. Protein extracts were resolved by SDS- PAGE and Western blotted.
Results: An alternative splice form of PAFAH 1B2 was isolated and sequenced. This isoform was observed in cDNA from human liver, moncytes, and T and B lymphocytes using PCR. This variant contains the first five exons of the native form protein and replaces exon 6 with an alternative 7th exon located downstream of exon 6. Exon 6 contains two residues involved in the protein’s active site triad, Asp and His, and are absent in exon 7. Computer modeling suggests replacement of exon 6 by exon 7 would abolish the active site and possibly alter the proteins’ ability to dimerize. Preliminary Western blots from selected tissues demonstrated the presence in liver of a new band consistent with the predicted size of the variant.
Conclusions: We hypothesize that this alternative splice likely decreases the proteins ability to function as a regulator of inflammation. We are presently carrying out gene expression analysis to determine the relative levels of the splice variant in different tissues and changes in expression associated with activation of leukocytes.
Endothelial Microparticles, Platelet and Leukocyte Activation and Cellular Interactions in Patients with Non-Valvular Atrial Fibrillation.
Authors: Chirinos Julio A. , Castrellon Aurelio , Jy Wenche , Horstmann Lawrence L. , Jimenez Joaquin J. , Willens Howard J. , Castellanos Agustin , Myerburg Robert J. , Ahn Yeon S. 
Published: April 2020

Abstract
Background: Atrial fibrillation (AF) is associated with a systemic pro-coagulant state. Coagulation involves complex interactions between endothelial and circulating cells, cell-derived microparticles and plasma proteins.
Methods: We investigated the levels of endothelial and platelet microparticles, leukocyte and platelet activation, and cell interactions in 48 patients with non-valvular AF and compared to normal controls. We performed flow cytometry in periheral venous blood to measure (1) Platelet expression of P-selectin, (2) Platelet microparticles; (3) Platelet-leukocyte conjugates; (4) Leukocyte expression of CD11b; (5) Endothelial microparticles (EMP) positive for CD31 and negative for CD42 (EMP31+), EMP positive for E-selectin (EMP62E+), CD54 (EMP54+), or CD51 (EMP51+); (6) EMP54+- and EMP62E+-leukocyte conjugates. Atrial fibrillation was confirmed electrocardiographically and left atrial volume was estimated by echocardiography. The mean age of patients with AF was 61.3±12 years. Congestive heart failure was present in 54.2% of patients, hypertension in 72.9%, and diabetes mellitus in 22.9%. Most patients (81%) were receiving anticoagulant therapy and 62.5% were receiving antiplatelet medications. Calcium channel blockers or digoxin were given to 43.8% and 54.2% of patients, respectively. The mean ventricular rate was 85.5±17 beats per minute, and the mean left atrial volume was 97.9 ml.
Results: Patients with AF had significantly higher levels of platelet P-selectin expression and platelet-leukocyte conjugates. P-selectin expression strongly correlated with platelet-leukocyte conjugate levels (r=0.77; p&lt;0.001; Figure 1). Patients with AF also demonstrated increased levels of free EMP31+, EMP62E+ and EMP51+, as well as EMP62E+-lymphocyte, -monocyte and -neutrophil conjugates. Levels of free EMP54+ were lower, whereas EMP54+- neutrophil and EMP54+-lymphocyte conjugates were higher among patients with AF. EMP62E+-neutrophil conjugates correlated with leukocyte expression of activation marker CD11b (r=0.42; p=0.003; Figure 2) and predicted CD11b expression independently of platelet-leukocyte conjugates (r2 increase=16%; p=0.003).
Conclusions: Patients with AF have increased levels of platelet and leukocyte activation, circulating endothelial microparticles, and binding of endothelial microparticles and platelets to leukocytes. Platelet activation is a determinant of platelet-leukocyte conjugate formation in AF. The formation of EMP62E-neutrophil conjugates is a major determining factor for circulating leukocyte activation in AF. Further studies are needed to assess the correlation of these markers with the risk of thromboembolism in AF.
Figure 1. Figure 1. Figure 2. Figure 2.
ADAMTS-13 Binds Platelets in a Specific, Divalent Cation and Activation Dependent Manner.
Authors: Artoni Andrea , Garagiola Isabella , Lombardi Rossana , Peyvandi Flora , Mannucci Pier Mannuccio 
Published: April 2020

Abstract
ADAMTS-13 cleaves high molecular weight von Willebrand factor (VWF) realeased by the endothelium in order to prevent massive intravascular platelets adhesion and aggregation as pathologically observed in thrombotic thrombocytopenic purpura. ADAMTS-13 is present at low levels in plasma. We therefore surmised that platelets are able to specifically bind the metalloprotease on their surface, hereby concentrating the enzyme where it is most required. With this as background, 96 wells polystyrene NUNC plates were coated either with albumin or fibrinogen or VWF or recombinant ADAMTS-13 (each at 10 μg/ml) and then blocked with 5% albumin overnight. Washed platelets (100,000/μl), incubated with divalent cations, were then let adhere to the wells for 1 hr at 37°C. After extensive washing adherent platelets were lysed, p-nitrophenilphosphate was added and the reaction was stopped with NaOH 2M. Detection was done by assessing optical density at 405 nm. Binding of washed platelets preincubated with 2mM CaCl2 and/or 2mM MgCl2 to wells covered with immobilized recombinant ADAMTS-13 was significantly higher than binding to wells coated with albumin (p&lt;0.001), was at the same levels of the binding to wells covered with recombinant VWF and approximately half of binding to the wells coated with fibrinogen. When washed platelets were preincubated with EDTA 2mM binding to the wells coated with fibrinogen or recombinant ADAMTS-13 decreased at the same degree of the wells covered with albumin. Preincubation of platelets with antibodies against αIIbβ3 (7E3, 10 μg/ml) or GpIb (10 μg/ml) did not effect the levels of binding to recombinant ADAMTS-13 while the binding to fibrinogen and VWF was totally abolished. Activation of platelets, obtained by preincubating platelets with ADP (5 μM) or collagen (10 μg/ml), significantly increased their binding to recombinant ADAMTS-13 (p&lt;0.001) as compared to the binding of non-activated platelets. Immunofluorescent studies were then performed to see whether or not ADAMTS-13 bound to the platelet plasma membrane using as primary antibody a murine anti-human ADAMTS-13 monoclonal antibody (13E2). A positive membrane fluorescent signal was detected using as a source of platelets either a normal donor or a patient with type III Von Willebrand disease, demonstrating that ADAMTS-13 is located on the platelet surface independently from VWF. In conclusion ADAMTS-13 binds to the surface of platelets, the binding is specific, activation and divalent cations dependent, inhibited by EDTA, and not mediated by VWF on the membrane of platelets; the binding site does not appear to be αIIbβ3 or GpIb. Hence it can be hypothesized that ADAMTS-13 on platelet membrane might cleave high molecular weight VWF.
Mechanisms of Static and Shear-Induced Platelet Adhesion: Differences in the Adhesion Supported by MMRN1 Comparisons with Other β3 Integrin Ligands.
Authors: Adam Frederic , Zheng Shilun , Santos Aurelio V. , Kelton John G. , Hayward Catherine P.M. 
Published: April 2020

Abstract
Platelet adhesion and aggregation at the site of vascular injury are key events in hemostasis and thrombosis. These processes are supported by interactions between platelet glycoprotein (GP) receptors (including integrin αIIbβ3, GP Ib-IX-V and GPVI) and ligands that include von Willebrand factor (VWF), collagen, and fibrinogen (Fg). Recently, the polymeric protein multimerin 1 (MMRN1) was identified to bind β3 integrins. Normally, MMRN1 is sequestered within secretion granules of platelets, megakaryocytes, and endothelium until its release. In static adhesion assays, MMRN1 supports platelet adhesion to integrins αIIbβ3 and αvβ3 by an RGD-dependent mechanism.
Study goals and methods: To further determine the mechanisms of MMRN1 binding to platelets, we investigated (i) the importance of platelet activation in MMRN1 binding to platelets, (ii) the ability of MMRN1 to support platelet adhesion compared to other adhesive ligands (Fg, VWF), and (iii) the role of β3 integrins in MMRN1 binding to platelets at low and high shear.
Results: The binding of secreted platelet MMRN1 to thrombin activated platelets was significantly reduced by antibody inhibitors of ligand binding to αIIbβ3 and αvβ3. Thrombasthenic platelets (GT), deficient in αIIbβ3 and αvβ3 integrins, stored normal quantities of MMRN1 but after activation, they retained 34% less MMRN1 than normal platelets. Platelet adhesion experiments confirmed that αIIbβ3/αvβ3 and other binding sites supported MMRN1 binding to platelets. MMRN1 supported platelet adhesion at both low (150 s-1) and high (1500 s-1) shear rates. Like platelet adhesion to VWF, platelet adhesion to MMRN1 was greater at high shear rates. Platelet stimulation by agonists was essential to induce platelet binding to MMRN1 in static and shear adhesion assays, but not to induce platelet adhesion to Fg and vWF. While platelets activated by ADP and TRAP showed similar adhesion to Fg and VWF, TRAP induced more platelet adhesion to MMRN1 at high shear rates than ADP. Inhibitors of ligand binding to αIIbβ3 and αvβ3 had greater effects on high compared to low shear platelet adhesion to MMRN1.
Conclusions: These data indicate interesting differences in the mechanisms that support platelet adhesion to MMRN1 and other β3 ligands, which could be important for molecular events in hemostasis and thrombosis. The activation-dependent binding of MMRN1 to platelets, augmented by high shear flow, may reflect the unique recognition properties of platelet β3 integrins and/or exposure of other binding sites (e.g. phosphatidylserine) on activated platelets that promote adhesive interactions with MMRN1.
A Rapid Test for the Diagnosis of Thrombotic Thrombocytopenic Purpura Using SELDI-TOF-Mass Spectrometry.
Authors: Wu Haifeng , Cataland Spero , Bissell Michael , Jin Ming 
Published: April 2020

Abstract
Thrombotic Thrombocytopenic Purpura (TTP), a life-threatening microangiopathic thrombotic disorder, requires immediate diagnosis and plasma exchange therapy. Development of TTP is related to functional deficiency of a metalloprotease, ADAMTS13, that leads to accumulation of ultra large von Willebrand factor (vWF) and subsequent platelet thrombosis. Currently no clinical test is available for a rapid detection of functional ADAMTS13 activity. In this study, a recombinant vWF peptide containing the ADAMTS13 cleavage site and a 6 X Histidine tag was used as a substrate for ADAMTS13. ADAMTS13 cleaved the substrate in a dose-dependent manner, generating a ~7739 Dalton peptide containing a 6 X Histidine tag. This cleaved peptide, bound to an IMAC/Nickel ProteinChip, was quantified using Surface Enhanced Laser Desorption/Ionization Time-of-flight Mass Spectrometry (SELDI-TOF-MS). The assay is capable of quantifying ADAMTS13 activity as low as 2.5 % in plasma within 3–4 hours. When the cleaved peptide was quantified as a ratio of an internal control peptide, the test displayed excellent reproducibility, with an average inter-assay CV of &lt; 33 %. Further validation of the test in healthy donors (n=39) revealed normal ADAMTS13 activity with a mean of 92.5% + 16.6. Sixteen patients with idiopathic TTP displayed mean ADAMTS13 activity of 1.73% + 3.62 at presentation, prior to any therapy. Further utility of this novel method includes functional determination of ADAMTS13 antibody titers in cases of acquired TTP. In summary, we have devised a novel SELDI-TOF-MS assay that offers a rapid, cost-effective, and functionally relevant test for timely diagnosis and management of TTP patients.
Combined Modality Treatment of Two or Four Cycles of ABVD Followed by Involved Field Radiotherapy in the Treatment of Patients with Early Stage Hodgkin’s Lymphoma: Update Interim Analysis of the Randomised HD10 Study of the German Hodgkin Study Group (GHSG).
Authors: Engert Andreas , Pluetschow Annette , Eich Hans T. , Herrmann Richard , Doerken Bernd , Kanz Lothar , Greil Richard , Markova Jana , Pfistner Beate , Josting Andreas , Mueller-Hermelink Konrad , Mueller Ralf P. , Diehl Volker 
Published: April 2020

Abstract
Combined modality treatment is regarded as standard by most study groups for patients with early-stage Hodgkin’s lymphoma (HL). However, the optimal chemotherapy, the number of cycles needed and the optimal radiotherapy dose is still unclear. The GHSG thus conducted a randomised study for patients with early stage favourable Hodgkin’s lymphoma (HD10) in which these questions were addressed.
A total of 1370 patients were randomised from 5/1998 to 1/2003 between two or four cycles of ABVD and independently to 20Gy or 30Gy involved field (IF) radiotherapy.
For the second interim analysis at a median follow up of 28 months, 847 patients were available. Patients were equally balanced for age, gender, stage, histology, performance status and risk factors. Compared with two cycles, there was more toxicity in patients receiving four cycles of ABVD for leucopenia, hair loss and infection. Concerning radiotherapy dose, there was more toxicity associated with 30Gy for dysphagia, mucositis and leucopenia. The rate of complete remissions ranged between 98% and 99% with no significant differences among treatment arms. Freedom from treatment failure (FFTF) and overall survival showed no differences between the four treatment arms. The curves for overall survival and FFTF were nearly superimposable for all four arms.
This analysis suggests that 2 chemotherapy cycles with involved field radiotherapy may be sufficient for patients with early favourable HL, but a reliable assessment must await the final analysis including all randomised patients and with adequate follow-up. The results of the third interim analysis (10/2005) including 1110 patients with a median follow up of more than 3 years will be presented.
Leucopenia during Treatment Is a Good Prognostic Risk Factor for Patients Undergoing Chemotherapy for Hodgkin’s Lymphoma: An Analysis of the German Hodgkin Study Group (GHSG).
Authors: Klimm Beate , Reineke Thorsten , Haverkamp Heinz , Eich Hans T. , Behringer Karolin , Josting Andreas , Pfistner Beate , Diehl Volker , Engert Andreas 
Published: April 2020

Abstract
Purpose: A systematic analysis of gender-specific factors in Hodgkin’s lymphoma (HL) studies previously revealed a better outcome for female HL patients. Factors contributing to better prognosis among female patients not only included more favorable risk factors at diagnosis, but also more treatment-induced severe leuopenia (WHO grade III/IV). The purpose of the current analysis was to characterize and investigate the protective role of severe leucopenia for both, male and female HL patients.
Patients and Methods: 4626 HL patients including 2050 females (f) and 2576 males (m) of all prognostic risk groups who were enrolled into the multicenter studies HD4-HD9 of the GHSG were evaluated. The median follow-up after treatment was 5.5 years.
Results: Female patients had a significantly better freedom from treatment failure (FFTF) with 81% at 66 months (95% confidence interval 79% – 82%), when compared with male patients (74%; 72% – 76%; p&lt;.0001). This was in part related to the occurrence of more acute chemotherapy-related leucopenia (WHO grade III/IV): 69.9% in female patients and 55.2% in male patients (p&lt;.0001). Furthermore, severe leucopenia during chemotherapy was strongly associated with better FFTF for both, male and female patients. Separate multivariate analyses showed that severe leucopenia remained significant when only male patients were included (0.011).
In addition, patients who developed severe leucopenia within the first two cycles of chemotherapy also had a significantly better FFTF (p=.0002) compared with all other patients (Klimm et al, JCO in press). When considering patients with advanced HL undergoing BEACOPP in baseline or escalated dose, the presence of severe leucopenia during chemotherapy (p=.0074) was associated with a better outcome. This finding was also confirmed when only the first two cycles of treatment were analyzed (p =.0205).
Conclusion: The protective role of severe leucopenia suggests evaluating of a more individualized therapy in future trials, that may be tailored in a response-adapted manner depending on the individual toxicity profile within the first cycles.
Cisplatin-Based Protocols as Salvage Therapy for Relapsed or Refractory Hodgkin’s Lymphoma Patients.
Authors: Alvarez Iván , Sureda Anna , Arranz Reyes , Córdoba Raúl , Xicoy Blanca , Sánchez Blanca , Bernal María Teresa , Roncero María Isabel G. , Martí Edelmira , Pliego Alberto , Fernández-Abellán Pascual , Ribera Josep María , Fernández-Rañada Jose María , Sierra Jorge 
Published: April 2020

Abstract
We have analyzed the results in terms of response rate and peripheral blood progenitor cell (PBPC) mobilization ability of two cisplatin-based chemotherapy salvage regimens [DHAP (cisplatin 100 mg/m2 iv day 1, ara-c 4 g/m2 iv day 2 and dexamethasone 40 mg po days 1-4) and ESHAP (etoposide 40 mg/m2 iv days 1–4, cisplatin 25 mg/m2 iv days 1–4, ara-c 2 g/m2 iv day 5 and methilprednisolone 500 mg iv days 1–5)] in a group of 110 patients with Hodgkin’s lymphoma (HL) in first or subsequent relapses. There were 70 males and 40 females with a median age at diagnosis of 29 years (range, 10 – 79). Sixty seven patients (64%) presented with advanced stage, 54% of them had B symptoms, 32% bulky mediastinal mass and 38%, extranodal disease. Disease status at the time of administration of the salvage protocol was primary refractory disease (PRD) (n = 16, 17%), first relapse (n = 65, 69%), second or subsequent relapse (n = 10, 11%) and relapse after a prior autologous stem cell transplantation (ASCT) (n = 3, 3%). Twenty-seven patients (26%) received the DHAP protocol and the remaining 78 (74%), the ESHAP protocol. Median time from diagnosis to the salvage therapy was 15 (range, 1 – 249) mo. In patients treated after a first relapse, the median duration of the first complete remission (CR) was 7 (range, 1 – 77) mo, with 18% of the patients relapsing after a long first CR (&gt; 12 mo). Median number of cycles administered per patient was 2 (range, 1 – 3) with a median time interval between cycles of 28 (range, 21 – 76) days. PBPCs were collected after the second and the third cycle of chemotherapy in 35% and 49% of the patients respectively and was successful (&gt; 2.0 x 106 CD34+ cells/kg) in 97% of them. Grade 3–4 hematological toxicity was seen in 20% of the cycles with severe neutropenia (&lt; 0.5 x 109/l granulocytes) and thrombocytopenia (&lt; 20 x 109/l platelets) developing in 26% and 7% of the cycles, respectively. The most frequent grade 3–4 extra-hematological toxicity was nausea/vomiting (30%). Procedure related mortality was 2%. Response rate (RR) was 78% [CR: 39%, partial remission (PR): 39%] with significant differences between patients treated for PRD [RR of 41% (CR: 12%, PR: 29%)] and those treated for disease relapse [RR of 86% (CR: 44%, PR: 42%)] (p = 0.005). Cisplatin-based regimens are a useful therapeutical strategy in the treatment of refractory or relapsed HL due to a high overall RR and an adequate PBPC mobilization ability. Results in terms of disease response are significantly worse in patients treated for PRD.