bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Characterization of the Bcl-2 Splice Variant Beta.
Authors: Schinkothe Timo , Leistert Conrad , Staib Peter 
Published: October 2019

Abstract
Bcl-2 family proteins are decisive regulators of the intrinsic apoptosis mechanisms. The best known antiapoptotic protein is Bcl-2, which functions via the interaction with proapoptotic proteins due to its association to mitochondrial membranes. Besides the widely described splice variant Bcl-2alpha (26kDa), another 22kDa splice variant Bcl-2beta exists. Bcl-2beta is described as a cytosolic and functionless protein, because of its transmembrane domain deficit.
In this study, we demonstrated for the first time that Bcl-2beta has a function and might act in the linkage between extrinsic and intrinsic pathway of apoptosis and may also play a role in hematopoietic malignancy. By performing binding studies using immuno-coprecipitation (IP) we were able to demonstrate that both splice variants bind to Bad and Bax. Furthermore, Bcl-2beta but not Bcl-2alpha is able to bind to the proapoptotic protein Bid which is localized in the cytoplasma. Bid is known as a linker which transmits an extrinsic apoptotic signal into the intrinsic pathway. Additionally, an overexpression of Bcl-2beta results in an increased chemoresistance to different cytotoxic drugs in-vitro. This effect was stronger than it was seen with the overexpression of Bcl-2alpha. We were also able to show an expression of Bcl-2beta in PBMC in 6 of 12 samples of patients with B-CLL. Bcl-2alpha was expressed in all cases. Using confocal laser scanning microscopy, we also analyzed the sub-cellular localisation of both splice variants.
Conclusion: Various models attempt to describe the mechanisms of Bcl-2 family proteins. It seems that Bcl-2beta is a protein which can function in the cytosole as well as membrane associated in an antiapoptotic manner. Its specific interaction with Bid suggests that Bcl-2beta is the cytosolic counterpart of the Bid induced pathway. The intracellular transformation from Bid to tBid, which links the extrinsic to the intrinsic apoptotic pathway, as well as the proapoptotic property of tBid could be inhibited by Bcl-2beta.
MDS1-EVI1 and EVI1 Overexpression Results in Changes in the Behavior of Murine Hematopoietic Cells.
Authors: Metais Jean-Yves , Wieser Rotraud , Dunbar Cynthia E. 
Published: October 2019

Abstract
We have found non-random patterns of retroviral integration in long-term hematopoietic repopulating cells in the rhesus macaque, with frequent integration events of MLV vectors into the MDS1-EVI1 gene complex. These findings, along with reports regarding frequent integration events in the same gene complex in patients with chronic granulomatous disease receiving MLV-transduced hematopoietic cells in a clinical trial and the ability of MLV vectors activating expression of this gene via integration to immortalize primary murine bone marrow cells, suggests these gene products could have important roles in normal and leukemic hematopoiesis. Expression from this gene complex can result in translation of at least three distinct proteins: MDS1, EVI1, and MDS1-EVI1. EVI1 has been the most studied protein of this locus. Its overexpression, as a consequence of chromosomal rearrangement or viral integration, is associated with leukemia. MDS1-EVI1 contains a PR domain that is lacking in EVI1 and is thought to possibly be antagonistic to EVI1, however the location of the integrations in our prior rhesus studies would indicate that overexpression of either gene product could be immortalizing. Both proteins share the same expression profile in normal tissues as well as most reports of myeloid leukemias. To investigate the impact of the three gene products on hematopoietic cells, we cloned murine mds1, evi1, and mds1-evi1 into the pMIEV-GFP retroviral vector and produced ecotropic vector particles. These were used to transduce the murine BaF3 hematopoietic cell line as a model to study the impact of expression of these various gene products. Gene expression analysis using Afflymetrix arrays demonstrated that both EVI1 and MDS1-EVI1 expression produced dramatic changes in gene expression profiles of these cells, compared to MDS1 and control vector. For instance, EVI1 transduced cells overexpressed oncogenes such as small G proteins belonging to the RAS family. There was modulation of genes implied in hematopoiesis, apoptosis, TGF beta signaling, and cell cycle. To assess changes in cell cycling of transduced BaF3 cells we used a flow cytometric assay, which unraveled an arrest in G1 phase only when EVI1 was overexpressed. These changes were concomitant to an increased metabolic activity as measured by an MTT assay. Further studies of these different pathways have to be performed in order to confirm the results obtained by the DNA chips analysis. Primary murine bone marrow cells could be immortalized after transduction by both EVI1 and MDS1-EVI1 vectors, compared to MDS1 and control vectors. Mice have been transplanted with primary bone marrow cells transduced with all vectors, and are being followed for hematopoietic changes or leukemia. In conclusion, both MDS1-EVI1 and EVI1 overexpression appear to result in marked changes in the behavior of primitive hematopoietic cells.
High Risk of Pregnancy Related Venous Thromboembolism in Women with a Hereditary Deficiency of Antithrombin, Protein C or Protein S in Concomitance of Other Thrombophilic Defects: A Retrospective Cohort Study.
Authors: Folkeringa Nienke , Brouwer Jan-Leendert P. , Korteweg Fleurisca J. , Veeger Nic J.G.M , Erwich Jan Jaap H.M. , van der Meer Jan 
Published: October 2019

Abstract
Venous thromboembolism (VTE)during pregnancy is still an important cause of maternal morbidity and mortality in the Western world. The risk VTE in pregnant women is five times higher than in non-pregnant women of the same age. This risk is increased by thrombophilic defects. In a family cohort study we assessed the risk of VTE during pregnancy/puerperium and the contribution of concomitant thrombophilic defects in women with hereditary antithrombin, protein C or protein S deficiencies.
Women were recruited from a previous large family cohort study, which was designed to estimate the risk of VTE in first degree relatives from probands with documented VTE and a deficiency of antithrombin, protein C or protein S. Probands were excluded from analysis. Blood samples of female relatives were tested on the index deficiencies and prothrombin G20210A, factor V Leiden, hyperhomocysteinemia and increased levels of VIII:C, IX:C and XI:C. Observation time was defined as the fertile period (from age 15–45 years), or until the first VTE, or until end of study period.
The cohort contained 222 female relatives, of whom 101 women were deficient and 121 non-deficient. The absolute risk of venous thromboembolism in deficient women was 1.76 per 100 person-years versus 0.19 per 100 person-years in non-deficient women (Relative Risk (RR) 9.2; 95% CI 3.8–26.7). Concomitance of none, one and more than one thrombophilic defect increased the risk in deficient (1.55, 2.14 and 2.92 per 100 person-years, respectively) and non-deficient women (0.16, 0.09 and 0.54 per 100 person -years, respectively). Annual incidences (AI) were lower in ever pregnant than never pregnant deficient women, 1.37 per 100 person-years versus 2.96 per 100 person-years (RR 0.5; 95% CI 0.2–0.99)(Table). These were 0.09 per 100 person-years versus 0.70 per 100 person-years in non-deficient women (RR 0.1; 95% CI 0.02–0.9). In ever pregnant deficient women 71% of VTE episodes were pregnancy related. A majority (75%) of never pregnant deficient women revealed VTE associated with oral contraceptives.
Women with hereditary antithrombin, protein C or protein S deficiencies are at high risk of VTE. Concomitance of other thrombophilic defects increased this risk. In fertile women most episodes of VTE are associated with either pregnancy or oral contraceptives.
Deficient Non-deficient Ever pregnant (n=54) Never Pregnant (n=47) Ever pregnant (n=79) Never pregnant (n=42) Women with VTE, n 17 12 2 3 Observation period, yr 1241 405 2169 430 AI, % (95% CI) 1.37 (0.80–2.19) 2.96 (1.53–5.18) 0.09 (0.01–0.33) 0.70 (0.14–2.04) RR (95% CI) 0.5 (0.2–0.99) P=0.05 0.1 (0.02–0.9) P=0.04 Pregnancy related VTE, n (%) 12 (71) 0 1 (50) 0 Oral contraceptive related VTE, n (%) 2 (12) 9 (75) 0 3 (100)
Risk of Pregnancy-Associated Venous Thromboembolism in Women with a History of Prior Thrombosis.
Authors: Gerhardt Andrea , Scharf Rudiger E. , Zotz Rainer B. 
Published: October 2019

Abstract
Background: Previous estimates of the rate of recurrent venous thromboembolism (VTE) during pregnancy in women with a history of VTE have vary between 0 and 13%. Therefore, the decision to administer or withhold heparin - especially in the antepartum period - has been discussed controversial. In a recent study by Brill-Edwards et al. (N Engl J Med2000;343:1439–44), no recurrences of VTE occurred in women (n=44) who had a previous episode of thrombosis that was associated with a temporary risk factor and who also had no evidence of thrombophilia. Based on these results, antepartum heparin prophylaxis is not routinely recommended in women without thrombophilia whose previous episode of thrombosis was associated with a temporary risk factor (ACCP guidelines 2004). The objective of our study was to evaluate the risk of recurrent pregnancy-associated thrombosis in women with a history of VTE.
Materials and Methods: We retrospectively studied 198 women with at least one pregnancy (275 pregnancies in total) after a one previous episode of VTE. Sixty-three women (81 pregnancies) were excluded from the analysis because of antepartum heparin prophylaxis.
Results: In the subgroup of women without heparin prophylaxis (n=135), 15 (7.7%) thromboembolic events occurred antepartum in 194 pregnancies. Further subgroup analysis, stratified for the nature of first VTE, gave the following number of antepartum VTE per number of pregnancies: 2 VTE/19 pregnancies (10.5%) in 14 women (first VTE: immobilization), 4 VTE/33 pregnancies (12.1%) in 24 women (first VTE: surgery), 5 VTE/69 pregnancies (7.2%) in 46 women (first VTE: oral contraception), 2 VTE/58 pregnancies (3.4%) in 40 women (first VTE: pregnancy), 2 VTE/15 pregnancies (13%) in 11 women (first VTE: idiopathic). Nine of the 15 women with VTE (7/13 women with first VTE triggered by temporary risk factor; 2/2 women with first idiopathic VTE) had a heterozygous factor V Leiden G1691A or prothrombin G20210A gene mutation. In the postpartum period, 16 VTE in 194 pregnancies occurred after live birth in the 135 women without heparin prophylaxis. Nine of these 16 women had a heterozygous FVL or prothrombin G20210A gene mutation. In Conclusion, the risk of recurrent antepartum VTE was similar in women with and without factor V Leiden G1691A or the prothrombin G20210A gene mutation and did not differ between women with first VTE triggered by a transient risk factor or an idiopathic first VTE. In addition to recommended postpartum heparin prophylaxis, our data support the need for a routine antepartum prophylaxis in women without thrombophilia whose previous episode of thrombosis was associated with a temporary risk factor.
Venous Thromboembolism - A Manifestation of the Metabolic Syndrome?.
Authors: Ay Cihan , Tengler Theres , Vormittag Rainer , Simanek Ralph , Dorda Wolfgang , Vukovich Thomas , Pabinger Ingrid 
Published: October 2019

Abstract
There is accumulating evidence for an association between atherosclerosis and venous thrombosis, which may share common risk factors. The metabolic syndrome (MetSyn), a cluster of interrelated risk factors comprising abdominal obesity, elevated blood pressure, high triglycerides, reduced high-density lipoprotein cholesterol and elevated fasting glucose plasma levels is associated with atherosclerotic disease and type 2 diabetes mellitus. It induces a proinflammatory and prothrombotic state. Despite its high prevalence, data on the association with venous thromboembolism (VTE) are scarce. Therefore, we aimed to investigate the association of the MetSyn with the risk for VTE and conducted a case-control study to evaluate the prevalence of the MetSyn according to guidelines of the National Cholesterol Education Program in a high-risk population of patients with objectively confirmed recurrent VTE, who had at least one unprovoked event of deep venous thrombosis or pulmonary embolism. Age and sex-matched healthy individuals served as controls. Finally, a total of 116 patients (53 female, mean age +/−SD: 56 years +/−12) and 129 controls (66 female, mean age +/−SD: 53 years +/−11) were recruited between January 2005 and November 2005. The prevalence of the MetSyn was statistically significantly higher in patients (40/116, 35%) than in controls (26/129, 20%, p=0.012). The unadjusted odds ratio (OR) of the MetSyn for VTE was 2.1 (95% CI [1.2–3.7], p=0.012) and remained statistically significant after adjustment for factor V Leiden, prothrombin G20210A variation and elevated factor VIII activity, sex and age (OR=2.2, 95% CI [1.1–4.2], p=0.024). Furthermore, individuals with the MetSyn (n=66) had significantly higher hs-CRP (median, [interquartile range]: 0.312 mg/dL, [0.142–0.751] vs. 0.153 mg/dL, [0.073–0.330], p<0.001), fibrinogen (390 mg/dL, [342–432] vs. 343 mg/dL, [310–394], p<0.001) and factor VIII activity (182%, [157–216] vs. 159%, [133–199], p=0.005) compared to those without (n=179). In conclusion, the MetSyn was statistically significantly overrepresented in patients with VTE compared to control subjects without a history of venous or arterial thrombosis. Our data suggest that the MetSyn may contribute to the development of VTE as it was associated with a 2-fold increased risk for VTE.
Thiopurine methyltransferase Genotype Is Not a Risk Factor for Secondary Malignant Neoplasias after Treatment for Childhood Acute Lymphoblastic Leukemia on Berlin-Frankfurt-Muenster Protocols.
Authors: Stanulla Martin , Schaeffeler Elke , Moericke Anja , Cario Gunnar , Eichelbaum Michel , Riehm Hansjoerg , Welte Karl , Schrappe Martin , Schwab Matthias 
Published: October 2019

Abstract
The thiopurines mercaptopurine and thioguanine are important components of contemporary polychemotherapeutic treatment protocols for acute leukemias. Thiopurines are prodrugs that undergo intestinal and hepatic metabolism. Activation occurs via a multistep pathway to form thioguanine nucleotides, which are thought to be the major cytotoxic compound through triggering cell cycle arrest and apoptosis. This process is in competition with direct inactivation of thiopurines or their metabolites by thiopurine S-methyltransferase (TPMT). TPMT is a cytosolic enzyme that is ubiquitously expressed in the human body and catalyzes the S-methylation of thiopurines. The TPMT locus is subject to genetic polymorphism, with heterozygous individuals (5 to 11% of Caucasians) having intermediate TPMT activity, and homozygous individuals (0.3 to 0.5% of Caucasians) having low TPMT activity. At least 20 variant TPMT alleles (*2 to *18) have been described so far that confer decreased enzyme activities compared to the TPMT*1 wild-type allele. TPMT genotype is highly concordant with TPMT phenotype. With regard to long-term adverse effects, patients who have diminished TPMT activity were shown to be at increased risk of developing chemotherapy-induced acute myeloid leukemia and radiation-induced second brain tumors tumors after exposure towards mercaptopurine during therapy for childhood acute lymphoblastic leukemia (ALL). To investigate if such an association is generalizable to other entities of secondary malignant neoplasms (SMN) and different treatment approaches for ALL, we collected specimens of 72 patients who developed a SMN after ALL treatment on Berlin-Frankfurt-Muenster (BFM) protocols, analyzed their TPMT genotype and compared genotype frequencies to these in the general ALL patient population. The 72 patient cohort consisted of 49 hematological SMN (half of them received cranial irradiation), 12 brain tumors, and 11 other solid SMN. Neither in the entire patient group nor in subgroup analyses, differences in allele frequencies of TPMT variants conferring diminished enzyme activity were detectable when comparing SMN patients to the overall ALL patient population. Thus, low TPMT activity does not seem to play a major role in the etiology of SMN after treatment for childhood ALL according to BFM treatment strategies. Factors potentially helpful for the explanation of the previously described relationsship of TPMT activity with SMN will be presented.
Identification and Targeting of a PAR1-PAR4 Complex in Human Platelets and Thrombosis.
Authors: Leger Andrew J. , Covic Lidija , Kuliopulos Athan 
Published: October 2019

Abstract
Thrombin is the most potent activator of platelets and plays a crucial role in the development of arterial thrombosis. Human platelets express dual thrombin receptors, a high-affinity PAR1 and low-affinity PAR4. Platelet aggregation studies demonstrated that PAR4 activity is markedly enhanced by thrombin-PAR1 interactions. PAR1-PAR4 co-factoring was shown by acceleration of thrombin cleavage and signaling of PAR4 upon co-expression with PAR1. A combination of bivalirudin (hirulog) plus a novel PAR4 pepducin antagonist, P4pal-i1, effectively inhibited aggregation of human platelets to even high concentrations of thrombin and prevented occlusion of carotid arteries in guinea pigs. Likewise, combined inhibition of PAR1 and PAR4 with small molecule antagonists and pepducins was effective against carotid artery occlusion. Co-immunoprecipitation and fluorescence resonance energy transfer studies demonstrated that PAR1 and PAR4 associate as a hetero-oligomer in human platelets and recombinant fibroblasts. Together these studies show that PAR1 and PAR4 form a stable hetero-oligomer that enables thrombin to act as a bivalent functional agonist. These studies suggest that targeting the PAR1-PAR4 hetero-oligomer may present a novel therapeutic opportunity in the prevention of arterial thrombosis.
Platelets Lacking Sialic Acid Clear Rapidly from the Circulation Due to Ingestion by Asialoglycoprotein Receptor-Expressing Liver Macrophages and Hepatocytes.
Authors: Louise Soerensen Anne , Wandall Hans H. , Patel Sunita , Richardson Jennifer , Italiano Joseph , Clausen Henrik , Stossel Thomas P. , Hartwig John H. , Hoffmeister Karin M. 
Published: October 2019

Abstract
Although surface sialic acid is considered a key determinant for the survival of circulating blood cells and glycoproteins, its role in platelet survival is unclear. We investigated the importance of sialic acid for platelet clearance using mice deficient in the ST3GalIV sialyltransferase gene (ST3GalIV−/− mice) and identified a novel clearance mechanism previously unrecognized for platelets. ST3GalIV catalyzes the addition of sialic acid onto exposed galactose residues of cell surface glycoproteins. ST3GalIV−/− mice have increased platelet surface galactose exposure, a 70% reduction in platelet count, and prolonged bleeding times. We report that ST3GalIV−/− platelets transfused into wild-type C57BL/6J mice exhibit markedly reduced recoveries and shortened survivals respectively compared to littermate wild-type platelets. Infusion of asialofetuin, an antagonist of the asialoglycoprotein-receptor (ASGPR) restored platelet recovery time and initial circulation of ST3GalIV−/− platelets to normal values. Immunohistochemical studies of organ specimens harvested shortly after transfusion of biotin-labelled platelets demonstrated the predominant clearance of ST3GalIV−/− platelets by the liver Kupffer cells and, unexpectedly, hepatocytes. Megakaryocytes cultured from ST3GalIV−/− mice produced proplatelets normally compared to megakaryocytes generated from wild-type littermates, indicating that the thrombocytopenia in the ST3GalIV−/− mice is not due to reduced platelet production. Comparison of ST3GalIV+/+ and ST3GalIV−/− platelet surface receptor expression as evidenced by flow cytometry and preliminary in vitro activation studies did not reveal any significant differences in the two genotypes. We conclude that the absence of terminal sialic acid residues on platelet surfaces exposes galactose residues to the lectin domain of ASGPR on both hepatocytes and liver Kupffer cells, resulting in platelet clearance from the circulation.
Tyrosine Phosphorylation of the Integrin β3 Subunit Regulates β3 Cleavage by Calpain.
Authors: Stojanovic Aleksandra , Flevaris Panagiotis , Xi Xiaodong , Chisti Athar , Phillips David , Lam Stephen C.-T. , Du Xiaoping 
Published: October 2019

Abstract
Outside-in signaling of β3 integrins induces and requires phosphorylation at tyrosine-747 (Y747) and tyrosine-759 (Y759) of the β3 subunit, but the mechanism for this requirement is unclear. On the other hand, a key consequence of integrin signaling, cell spreading, is inhibited by calpain cleavage of β3 cytoplasmic domain. Here we show that tyrosine phosphorylation in the synthetic β3 cytoplasmic domain peptide inhibits calpain cleavage. In platelets, tyrosine phosphates inhibitor, sodium vanadate, enhances thrombin-induced phosphorylation at Y747 and Y759, which is associated with the reduced integrin cleavage by calpain. The effects of sodium vanadate is unlikely to be caused by its effects on calpain activity but is likely to be caused by the susceptibility of integrin cytoplasmic domain, because sodium vanadate did not affect the calpain cleavage of another substrate, fodrin, in platelets. To further support the protective effect of tyrosine phosphorylation against calpain cleavage, we show that mouse β3 (DiYF) with both Y759 and Y747 mutated to phenylalanine is more susceptible to calpain cleavage than wild type during thrombin-induced platelet aggregation. Furthermore, phosphorylation at Y747 and Y759 of β3 in the focal adhesion sites and the leading edge of spreading platelets was differentially regulated. Selective dephosphorylation of Y759 is associated with calpain cleavage at Y759. Thus, one mechanism by which tyrosine phosphorylation promotes integrin signaling and cell spreading is its inhibition of calpain cleavage of the β3 cytoplasmic domain.