bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activated Protein C-Resistance Induced by a Low Molecular Weight Inhibitor.
Authors: Kalafatis Michael , Chiott Rihard E. , Branda Richard F. , Mann Kenneth G. 
Published: October 2019

Abstract
Activated protein C (APC) inactivates factor Va (fVa) following three cleavages in the heavy chain at R506, R306 and R679. Cleavage at R506 precedes cleavage at R306. Cleavage at Arg306 is strictly lipid-dependent and results in total inactivation of the factor Va molecule with dissociation of fragments from the A2 domain from the rest of the molecule. Factor VLeiden is associated with an R→Q substitution at position 506 and is present at approximately 8% of the Caucasian population. The heterozygous presentation of factor VLeiden results in delayed inactivation of factor Va and “APC-resistance” with attendant increased risk of venous thrombosis. However, not all cases of “APC-resistance” are explained by factor VLeiden. We observed “APC-resistance” in a patient displaying heterozygous factor VLeiden, Waldenstrom’s macroglobulinenemia, systemic lupus erythrematosus (anticoagulant) and a history of coronary artery disease. The patient’s plasma resistance to APC inactivation was not repaired by immunodepletion of his factor VLeiden and replacement by normal plasma factor V. Conversely when the patient’s fVa was returned to factor V immunodepleted normal plasma it did not display APC-resistance. Cleavage of the patient’s plasma fVa at R306 was not detected following prolonged incubation of his clotted plasma at 37°C even when 2 nM APC was added following clotting. These data suggested that the APC-resistance observed in the patient was not due to the presence of factor VLeiden, but due to some property which inhibited the lipid dependent cleavage at Arg306. The patient’s plasma was depleted of IgG/IgM and the purified immunoglobulin fraction assessed for inhibition of APC cleavage and inactivation of fVa in a system using purified reagents. The data were compared with the inhibition of fVa inactivation by APC by an IgG/IgM fraction obtained from normal plasma under similar experimental conditions. No inhibition of APC cleavage and inactivation of fVa by the IgM/IgG fraction obtained from either plasma were observed. In addition, the fVa molecule contained in the IgM/IgG-depleted patient plasma was still resistant to cleavage and inactivation by APC. Following dialysis the patient’s plasma lost its ability to inhibit fVa cleavage and inactivation by APC. Overall these studies indicate that inhibition of fVa cleavage and inactivation by APC in the patient’s plasma is caused by a hitherto undescribed metabolite of low molecular weight. The mechanism of action of this metabolite is not yet known, but the evidence suggests that the metabolite interferes with the lipid-dependent cleavage and inactivation of fVa by APC at R306. These data demonstrate the existence of an as yet unknown APC inhibitor of low molecular weight in the plasma of a patient with lupus anticoagulant and severe thrombotic symptoms.
Compound Heterozygosity in the Novel Mutations W157R and T591K in the γ-Glutamyl Carboxylase Gene Causes Hereditary Combined Vitamin K-Dependent Coagulation Factor Deficiency in a Tunisian Family.
Authors: Darghouth Dhouha , Hallgren Kevin W. , Hain Rebecca L. , Mrad Amel , Gharbi Youssef , Maherzi Ahmed , LeRicousse Sophie , Kastally Radhia , Berkner Kathleen L. , Rosa Jean-Philippe 
Published: October 2019

Abstract
Combined deficiency in vitamin K-dependent (VKD) coagulation factors is an autosomal recessive bleeding disorder associated with defects in either the VKD carboxylase which converts Glus to Glas in VKD proteins to render them active or the vitamin K epoxide reductase (VKORC1) which supplies the reduced vitamin K cofactor required for carboxylation. Such defects are rare, and we now report the fourth case of deficiency caused by mutations in the carboxylase gene. The mutations were identified in a two year old Tunisian girl who exhibited impaired function in several VKD procoagulant and anticoagulant factors that was not restored by vitamin K administration. Sequence analysis of the propositus did not identify any mutations in the VKORC1 gene but, remarkably, revealed three heterozygous mutations in the carboxylase gene, D31N, W157R and T591K within exons 2, 4 and 13, respectively. None of these mutations have previously been reported. Family analysis showed that D31N and T591K were coallelic and transmitted by the mother while W157R was transmitted by the father. The mutations were not found in the genomes of 200 normal subjects, ruling out frequent polymorphisms. Mutational analysis indicated wild type activity for the D31N carboxylase. In contrast, the W157R and T591K enzymes had activities that were, respectively, 7% and 0% that of wild type carboxylase, and their compound heterozygosity can therefore account for defective carboxylation. Residues 157 and 591 are both highly evolutionarily conserved, and residue 157 lies within a region previously suggested to be important for carboxylase binding to VKD Glus or propeptide. However, the hydrophobic nature of this region and inability of vitamin K administration to restore VKD protein function alternatively suggests that residue 157 may be important for vitamin K binding.
Response to Treatment of Helicobacter Pylori in Patients with Immune Thromboctypenic Purpura: A Systematic Review and Metaanalysis.
Authors: Bussel James B. , Ostrow Allison , Segal Jodi B. 
Published: October 2019

Abstract
Background: Patients with immune thrombocytopenic purpura (ITP) infected with Helicobacter pylori (H. pylori) are often treated with antibiotics to eradicate infection and raise platelet counts. We aimed to systematically review the evidence regarding this practice to better quantify response rate.
Study Design and Methods: We searched MEDLINE through April 2005, without language restriction; reviewed reference lists and queried experts for articles describing treatment of ITP with antibiotics targeting H. pylori. We included studies of any design involving more than 5 patients. Response rates were tabulated using the authors’ definitions, and pooled using a random effects model. Techniques of meta-regression were used to assess whether patient or study characteristics influenced response rates.
Results: We retrieved 52 potentially eligible studies. Of these, 16 studies met our inclusion criteria. From 10 studies, we had individual level patient data. None of the studies was a controlled trial. The pooled response rate (both partial and complete responses) was 45% [95% confidence interval (C.I.) 32% to 58%]. The number of previous treatments (0–1, 2, 3 or more) influenced the response rate with an 18% (p=0.001) decline in response rate with each higher category; duration of disease did not independently predict response. In analyses of individual patient data, quartile of platelet count upon entry also influenced response rate; 58% of patients in the highest quartile responded compared to 34% in the lowest quartile (p=0.018).
Conclusions: No randomized controlled trial has tested H. pylori eradication with antibiotics as a treatment for ITP. The sixteen observational studies we reviewed were fairly consistent with approximately half of treated patients having a platelet response to therapy. Without control groups, these studies do not provide strong evidence to support practice recommendations. However, given the low toxicity of antibiotic therapy, this treatment may be appropriate for patients who have not demonstrated refractoriness to multiple therapies.
Response Rates by Number of Previous Treatments Response Rates by Number of Previous Treatments
The Effect of Polygonum Multiflorum Extracts on Hematopoiesis and Platelet Production.
Authors: Yang Mo , Huang Wei Zhe , Pong Nga Hin , Liu Ai Guo Liu , Li Chi Kong , Ng Pak Cheung , Fok Tai Fai , Li Karen Kwai Har 
Published: October 2019

Abstract
To date, there is no ideal treatment for thrombocytopenia. We have proposed a possible mechanism of serotonin (5-HT) on megakaryocyte (MK) differentiation and platelet formation (Yang et al, Blood, 2003 suppl). The root of polygonum multiflorum thunb (Heshouwu) is an important ingredient of many commonly used prescriptions in Chinese medicine for promoting blood production. Polygonum multiflorum extracts (PME) also inhibit monoamine oxidase (MAO) and increase the level of 5-HT. Therefore, we hypothesize that polygonum multiflorum may have a promoting effect on thrombopoiesis via inhibition of monoamine oxidase (MAO) to increase 5-HT levels. The objective of this study was to investigate the hematopoietic role of PME in irradiated mice. PME (125 mg/kg/day) and TPO (12.5 ug/kg/day) were given by intra-peritoneal injection daily for 21 days starting from the day after irradiation (4 Gy). Peripheral blood platelets, white blood cells (WBC), and red blood cells (RBC) were analyzed from PME, TPO, and vehicle control groups on day 0, 7, 14 and 21. On day 21, the mice were sacrificed and bone marrow cells were harvested for CFU-MK, CFU-GM, BFU-E, CFU-GEMM and CFU-F (fibroblastoid) assays (n=8). We also investigated the in vitro effect of PME on CFU-F formation. Our results showed that PME enhanced the recovery of platelets, WBC, and RBC counts. Moreover, PME also promoted CFU-MK (30 ± 8 vs 15 ± 3 colonies/2 x 105 cells, p<0.01), CFU-GM (38 ± 7 vs 28 ± 7 colonies/2 x 105 cells, p<0.05), BFU-E (19 ± 3 vs 12 ± 4 colonies/2 x 105 cells, p<0.05), and CFU-F formation (36 ± 11 vs 23 ± 7 colonies/2 x 106 cells, p<0.01). Similar results were obtained in TPO-treated group. In in-vitro study, we further analyzed the effect of PME (0–500 ug/ml) on mouse CFU-F formation. The results showed that PME at 100–500 ug/ml significantly enhanced CFU-F formation (p<0.05, n=6). Our studies showed that PME enhances thrombopoiesis in vivo and the growth of bone marrow stromal cells in vitro. Therefore, we speculate that the thrombopoietic activity of PME may be mediated via promoting the bone marrow stromal cells. Although TPO has been effective as an agent for the recovery of platelet production after the onset of thrombocytopenia, long-term clinical usage of TPO may induce potential side effects such as thrombosis. Here we reported that the effect of PME is comparable with that of TPO on hematopoiesis and the production of platelets.
Monoclonal IgG Specific for the CD44 Antigen Mimics the Action of IVIg in the Amelioration of ITP.
Authors: Song Seng , Crow Andrew R. , Siragam Vinayakumar , Freedman John , Lazarus Alan 
Published: October 2019

Abstract
Previous work in our laboratory has shown that both IVIg and “anti-D like” erythrocyte-reactive antibodies ameliorate immune thrombocytopenia (ITP) in a murine model. However, they appear to function through different mechanisms: IVIg is dependent upon the inhibitory Fc receptor, FcγRIIB in the amelioration of ITP, but the anti-erythrocyte antibodies function independently of FcγRIIB expression. We have also demonstrated that anti-erythrocyte antibodies down-modulate the expression of the activating Fc receptor, FcγRIIIA in splenic macrophages during the amelioration of ITP. A monoclonal antibody to CD44, cell surface protein involved in cell homing, cancer progression and inflammation, can also ameliorate murine ITP. Elucidation of the mechanisms of action of anti-CD44 antibodies in the amelioration of ITP would be critical to the successful application of this potential therapy. In this report, two monoclonal antibodies against CD44, KM114 and IM7 were studied in C57BL/6 and FcγRIIB−/− mice to assess their therapeutic activity in treating ITP. Both KM114 and IM7 bound well to splenic cells from all mice tested. Neither KM114 nor IM7 demonstrated any in vitro anti-idiotypic activity which could neutralize the binding of the thrombocytopenia-inducing anti-platelet antibody. At the dose that protected against thrombocytopenia, KM114 did not mediate RES blockade. In contrast, IM7, which did not at all protect against thrombocytopenia, blocked RES. Since FcγRIIB has been documented to play a key role in the function of IVIg in the amelioration of ITP, we questioned the significance of it in the function of KM114. Surprisingly, KM114 was not able to ameliorate ITP in mice genetically deficient in FcγRIIB. These results suggest that, like IVIg, monoclonal antibody against CD44 mediates amelioration of murine thrombocytopenia in a manner dependent upon the inhibitory FcγRIIB rather than via RES blockade.
Inhibition of IL-1β and TNFα Gene Expression by IVIg or Anti-Red Blood Cell Antibodies in a Mouse Model of ITP.
Authors: Aubin Eric , Bazin Renée , Lemieux Réal 
Published: October 2019

Abstract
Plasma-derived human IgG (IVIg) have been used for more than 2 decades for the treatment of several autoimmune diseases such as ITP, even if their mechanism of action is still not fully understood. Recently, several studies with IVIg-treated patients have shown that IVIg can modulate the serum level of both pro-inflammatory and anti-inflammatory cytokines. In ITP, it is known that the destruction of autoantibody-coated platelets occurs mainly in the spleen. We thus used a mouse model of ITP to evaluate the modulatory effects of IVIg on the expression of several cytokine genes in the spleen of the animals by quantitative RT-PCR. The results showed that the induction of platelet destruction following injection of monoclonal anti-platelet antibodies (MWReg30) in BALB/c mice did not change the expression level of IL-1ra and IL-10 (anti-inflammatory cytokines) and IL-6, IFNγ and MCP-1 (pro-inflammatory cytokines). In contrast, MWReg30-treated mice showed an increase in IL-1β and TNFα mRNA expression by up to 4.2 and 2.1 fold respectively compared to control mice. Treatment of thrombocytopenic mice with IVIg (2g/Kg) prevented the increase of IL-1β mRNA but not TNFα mRNA. In parallel, the effect of anti-red blood cell (anti-RBC) antibodies, used to mimic anti-D treatment of ITP patients, was analysed. The results were similar to those observed with IVIg for IL-1β mRNA, but in contrast to IVIg, anti-RBC treatment also prevented the increase in TNFα gene expression, suggesting that the mechanisms of action of IVIg and anti-D in ITP treatment are different, in agreement with previous studies. In summary, we showed that IVIg and anti-RBC treatments attenuate the expression of important pro-inflammatory cytokines. IL-1β and TNFα are known to increase the phagocytic activity of macrophages and also to enhance the production of antibodies by B cells. Therefore, IVIg and anti-D could contribute to the prevention of platelet destruction in ITP by limiting the activation of phagocytes and the production of autoantibodies. This study was assisted by a grant from the Bayer/CBS/HQ partnership Fund to RB and RL.
BLIMP-1 Is a Target of Cellular Stress and Downstream of the Unfolded Protein Response.
Authors: Doody Gina , Stephenson Sophie , Tooze Reuben 
Published: October 2019

Abstract
Human B lymphocyte-induced maturation protein-1 (BLIMP-1) was originally described as a repressor of the interferon-beta response to viral infection. Subsequently, the murine orthologue was identified as a regulator of plasma cell differentiation. The involvement of BLIMP-1 in hemopoietic differentiation is not restricted to the B-cell lineage as BLIMP-1 is induced during differentiation of myeloid progenitors. During in vitro macrophage and plasma cell differentiation the expression of BLIMP-1 is cytokine driven. However, the BLIMP-1 response to virus infection can be reproduced by transfection with double-stranded RNA (dsRNA), indicating that BLIMP-1 is a target of dsRNA responsive signaling pathways. A central regulator of the intracellular response to viral infection is the interferon-inducible double-stranded RNA activated kinase, PKR. PKR belongs to a family of kinases that phosphorylate the eukaryotic translation initiation factor 2-alpha (eIF2α) and activate common downstream signaling pathways. PERK, the endoplasmic reticulum (ER) PKR-homologue is activated during the unfolded protein response (UPR), a stress response involved in both macrophage activation and terminal B-cell differentiation. This suggested the hypothesis that BLIMP-1 may represent a shared target of signaling pathways in the response to cellular stresses such as virus infection and the UPR. In this study we demonstrate that BLIMP-1 is rapidly upregulated during the UPR in human myeloid and B-cell lines. This response is conserved in primary murine macrophages, in which mimics of physiological stress and classical activation stimuli also induce Blimp-1. During the UPR, BLIMP-1 mRNA is induced at the level of transcription, with enhanced recruitment of RNA polymerase II to the BLIMP-1 promoter. Furthermore the stress response is limited to induction of BLIMP-1α mRNA and does not affect levels of an alternate transcript encoding a truncated protein, BLIMP-1β. The common induction of BLIMP-1 mRNA by stimuli which trigger the UPR supports the hypothesis that BLIMP-1 is a target of the eIF2α kinase family. To test this hypothesis directly, we employed a dominant negative mutant PERK. Our data demonstrate that the BLIMP-1 response to UPR stress is dependent on an intact PERK signaling pathway. Collectively our results provide evidence for a novel link between cellular stress, the eIF2α kinase family and a regulator of differentiation in macrophages and B-cells.
Reciprocal Interaction of Monocytes and NK Cells by Activation-Induced Expression of Ligands for the Activating Immunoreceptor NKG2D.
Authors: Krusch Matthias , Kloss Mercedes , Peterfi Andrea , Kumbier Ingrid , Kanz Lothar , Kiener Peter A. , Salih Helmut R. 
Published: October 2019

Abstract
Reciprocal Interactions of NK cells with Dendritic Cells (DC) can induce activation of NK cells, maturation or lysis of DC and influence subsequent adaptive immune responses. However, little is known about the interaction of peripheral blood monocytes with NK cells, especially regarding involved immunoregulatory surface molecules. Here we report that monocytes express ligands for the activating immunoreceptor NKG2D expressed on NK cells upon treatment with various stimuli. Incubation of monocytes with TNF, GM-CSF, IFN-g and various TLR ligands (LPS, Pam3Cys, R848, PolyI:C) induced surface expression of the NKG2D ligands (NKG2DL) MICA and to a lesser extent MICB, but no relevant changes of ULBP molecules, as determined by FACS analysis. Expression was confirmed by quantitative PCR analysis of NKG2DL mRNA induction. To elucidate the functional consequences of NKG2DL expression on monocytes for NK cell functions we performed coculture assays of monocytes and autologous NK cells. NKG2DL expression on stimulated monocytes lead to a significant induction of IFN-g release into the culture supernatant by NK cells as determined by ELISA. This IFN-g release was blocked by addition of a NKG2D-Ig fusionprotein, but not by isotype control demonstrating that the induction of NK cell IFN-g production was in fact specifically due to NKG2DL expression on monocytes. Since both monocytes and NK cells rapidly migrate to sites of inflammation, and monocytes display a high plasticity regarding their function and maturation which is influenced by IFN-g, our data indicate that NKG2DL expression on monocytes might not only mediate reciprocal activation of NK cells and monocytes but also might influence other components of the innate and adaptive immune system and thereby determine the course of subsequent immune reactions.
Platelet Binding to Monocytes Induces Changes in Integrin Functionality Promoting Monocyte Adhesion and Transendothelial Migration. Do Platelets Migrate Along?.
Authors: Martins Paula da Costa , van Gils Janine M. , Mol Anita , Hordijk Peter L. , Zwaginga Jaap-Jan 
Published: October 2019

Abstract
Monocyte adhesion to and transmigration across the endothelium are essential steps in atherogenesis. We have shown that the adhesive interactions between monocytes and the activated endothelium are increased when platelets bind to the monocyte surface and form platelet-monocyte complexes (PMC). PMC formation is dependent on interactions between platelet-displayed P-selectin and PSGL-1 on the monocyte surface. To better understand the effect of platelet binding on the capacity of monocytes to adhere to activated endothelium the P-selectin-PSGL-1 interaction - induced changes in integrin functionality were studied. The binding of platelets to monocytes via P-selectin-PSGL-1 interactions was shown to increase expression and activity of α4 beta;1 - and αM β2 - integrins which, resulted in increased monocyte adhesion to ICAM-1, VCAM-1, fibronectin and subsequently to stimulated endothelial cells. Platelet binding also induced monocyte migration (up to a 3-fold increase), compared to monocytes without platelets on their surface. To investigate the role of platelets in this process we determined the fate of platelets (within the PMC) during monocyte transendothelial migration. After forming PMC by mixing freshly isolated and fluorescently labeled platelets and monocytes, PMC were seeded on endothelial cells cultured on top of a fibrin gel. The cells were allowed to migrate across the endothelial layer into the gel where afterwards the position of platelets and monocytes was analyzed by confocal laser scanning microscopy. We found that the platelets were retained at the endothelium, suggesting that they detach from the PMC and are left behind on the endothelial layer upon monocyte transendothelial migration. In line with this we observed that the monocytes that were in the fibrin gel, underneath the endothelial layer, did not carry any platelets. This was confirmed by PMC migration over endothelial layered transwell filters since almost only monocytes were found in the lower compartment after migration. After testing different migration barriers, platelets seem to be shed from the monocyte surface upon monocyte migration by mechanical stress rather than only endothelial interaction. Our data suggest that monocytes bound to platelets are in a higher state of activation and have an increased atherogenic capacity. Furthermore, platelets seem to mainly play a role in the monocyte recruitment to the endothelium because once the monocytes cross the endothelial layer, platelets detach from their surface. Altogether, our findings, by showing that PMC have a strong atherogenic capacity, might be helpful in finding new therapeutic ways to prevent atherosclerosis and inflammation.