163 research outputs found
Strike point splitting induced by the application of magnetic perturbations on MAST
Divertor strike point splitting induced by resonant magnetic perturbations
(RMPs) has been observed on MAST for a variety of RMP configurations in a
plasma scenario with Ip=750kA where those configurations all have similar
resonant components. Complementary measurements have been obtained with
divertor Langmuir probes and an infrared camera. Clear splitting consistently
appears in this scenario only in the even configuration of the perturbation
coils, similarly to the density pump-out. These results present a challenge for
models of plasma response to RMPs.Comment: 9 pages, 4 figures, submitted to the proceedings of the 20th
Conference on Plasma Surface Interactions, to be published in the Journal of
Nuclear Material
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P2Y12 Receptor Blockade Augments Glycoprotein IIbβIIIa Antagonist Inhibition of Platelet Activation, Aggregation, and Procoagulant Activity
Background: New antiplatelet agents that provide greater, more consistent inhibition of the platelet ADP receptor P2Y12 may be used in combination with glycoprotein (GP) IIbβIIIa antagonists, but their combined effect on platelet function and procoagulant activity is not well studied. Therefore, the objective of this study was to evaluate the independent and complementary effects of P2Y12 and GPIIbβIIIa inhibition on platelet function and procoagulant activity. Methods and Results: Healthy donor blood was treated with the active metabolite of prasugrel (Rβ138727 5 ΞΌmol/L), GPIIbβIIIa antagonists (abciximab 3 ΞΌg/mL or eptifibatide 0.9 ΞΌg/mL), and combinations thereof, exposed to physiologically relevant agonists (collagen and ADP) and then evaluated for markers of platelet activation and procoagulant activity. Significant interactions between Rβ138727 and GPIIbβIIIa antagonists were observed. Rβ138727 and the GPIIbβIIIa antagonists had additive inhibitory effects on collagenβstimulated platelet aggregation and on the collagen plus ADPβstimulated level of activated platelet surface GPIIbβIIIa. Rβ138727 and abciximab each inhibited collagen plus ADPβstimulated platelet phosphatidylserine expression and prothrombin cleavage, and the combination produced greater inhibition than achieved with abciximab alone. In contrast, eptifibatide did not inhibit, but instead enhanced, collagen plus ADPβstimulated prothrombin cleavage. Addition of Rβ138727 reduced prothrombin cleavage in eptifibatideβtreated samples, suggesting a novel mechanism for potential benefit from combined prasugrel and eptifibatide treatment. Conclusions: The complementary effects of abciximab and Rβ138727 on platelet activation, aggregation, and procoagulant activity suggest their combined use may, to a greater degree than with either agent alone, reduce thrombus formation in vivo
Study of plasma protein C and inflammatory pathways: Biomarkers for dimethylnitrosamine-induced liver fibrosis in rats
Abstract The present investigation was designed to identify potential biomarker(s) and assess the involvement of inflammatory pathway in dimethylnitrosamine (DMN)-induced liver fibrosis in rats. Following DMN-treatment (10 mg/ml/kg, i.p., given three consecutive days each week for 4 weeks) body and liver weights were significantly decreased concurrent with increasing severity of liver damage assessed by bridging fibrosis, a histopathologic assessment and characteristic of human liver disease. Protein C along with albumin, C-reactive-protein (CRP), haptoglobin and total protein were significantly reduced and correlated with changes in liver histopathology. Biochemical markers of liver functions were significantly increased and correlated with changes in liver histopathology and plasma levels of protein C. Soluble intracellular-adhesion-molecule -1 (sICAM-1) levels were increased significantly but were poorly correlated with histopathology and protein C levels. Inflammatory chemokines and other analytes, monocyte-chemoattractant-protein-1 and 3 (MCP-1 and MCP-3), macrophage-colony-stimulating-factor (M-CSF) were significantly increased during the disease progression, whereas macrophage-derived-chemokine (MDC) and CRP were significantly suppressed. Circulating neutrophils and monocytes were also increased along with disease progression. The differential changes in sICAM-1, hyaluronic acid, gammaglutamyltranspeptidase (GGT), neutrophil and other inflammatory chemokines suggest the involvement of inflammatory pathways in DMNinduced liver fibrosis. In conclusion, the progressive changes in protein C along with other noninvasive biochemical parameters whose levels were significantly correlated with disease progression may serve as biomarkers for pharmacological assessment of targeted therapy for liver fibrosis
Relationship of Platelet Reactivity With Bleeding Outcomes During Long-Term Treatment With Dual Antiplatelet Therapy for Medically Managed Patients With Non-ST-Segment Elevation Acute Coronary Syndromes
Background--The relationship between "on-treatment" low platelet reactivity and longitudinal risks of major bleeding dual antiplatelet therapy following acute coronary syndromes remains uncertain, especially for patients who do not undergo percutaneous coronary intervention. Methods and Results--We analyzed 2428medicallymanaged acute coronary syndromes patients fromthe Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes (TRILOGY ACS) trial who had serial platelet reactivity measurements (P2Y12 reaction units; PRUs) and were randomized to aspirin+prasugrel versus aspirin+clopidogrel for up to 30 months. Contal's method was used to determine whether a cut point for steady-state PRU values could distinguish high versus low bleeding risk using 2-level composites: Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) severe/life-threatening or moderate bleeding unrelated to coronary artery bypass grafting (CABG) and non-CABG Thrombolysis In Myocardial Infarction (TIMI) major orminor bleeding. Exploratory analyses used 3-level composites that incorporatedmild andminimalGUSTOand TIMI events.Continuousmeasures of PRUs (per 10-unit decrease)were not independently associatedwith the 2-levelGUSTO (adjusted hazard ratio [HR], 1.01; 95% CI, 0.96-1.06) or TIMI composites (1.02; 0.98-1.07). Furthermore, no PRU cut point could significantly distinguish bleeding risk using the 2-level composites.However, the PRUcut point of 75 differentiated bleeding riskwith the 3-level composites ofGUSTO(26.5% vs 12.6%; adjusted HR, 2.28; 95% CI, 1.77-2.94; P<0.001) and TIMI bleeding events (25.9% vs 12.2%; adjusted HR, 2.30; 95% CI, 1.78-2.97; P<0.001). Conclusions--Among medically managed non-ST-segment elevation acute coronary syndromes patients receiving prolonged dual antiplatelet therapy, PRU values were not significantly associated with the long-term risk of major bleeding events, suggesting that low on-treatment platelet reactivity does not independently predict serious bleeding risk
Detection of conjugation related type four secretion machinery in Aeromonas culicicola
BACKGROUND: Aeromonas sp. can now be considered relatively common enteropathogens due to the increase of diseases in humans. Aeromonas culicicola is a gram negative rod-shaped bacterium isolated for the first time from the mosquito mid-gut, but subsequently detected in other insects and waters also. Our previous study discovered that A. culicicola harbors three plasmids, which we designated as pAc3249A, pAc3249B and pAc3249C. We investigated and report here the existence and genetic organization of a Conjugal Type IV Secretion System (TFSS) in pAc3249A. METHODOLOGY/PRINCIPLE FINDING: The complete operon is 11,061 bp in length and has G+C content of 47.20% code for 12 ORFs. The gene order and orientation were similar to those found in other bacteria with some differences. We have designated this system as AcTra for Aeromonas culicicola transfer system. BLAST results of ORFs and phylogenetic analysis showed significant similarity towards the respective proteins of the IncI2 plasmid R721 of E. coli. Other bioinformatics studies have been performed to predict conserved motifs/domains, signal peptides, transmembrane helices, etc. of the ORFs. CONCLUSIONS/SIGNIFICANCE: BLAST results of ORFs and phylogenetic analysis showed significant similarity towards the respective proteins of the IncI2 plasmid R721 of E. coli
An Anomalous Type IV Secretion System in Rickettsia Is Evolutionarily Conserved
Bacterial type IV secretion systems (T4SSs) comprise a diverse transporter family functioning in conjugation, competence, and effector molecule (DNA and/or protein) translocation. Thirteen genome sequences from Rickettsia, obligate intracellular symbionts/pathogens of a wide range of eukaryotes, have revealed a reduced T4SS relative to the Agrobacterium tumefaciens archetype (vir). However, the Rickettsia T4SS has not been functionally characterized for its role in symbiosis/virulence, and none of its substrates are known.Superimposition of T4SS structural/functional information over previously identified Rickettsia components implicate a functional Rickettsia T4SS. virB4, virB8 and virB9 are duplicated, yet only one copy of each has the conserved features of similar genes in other T4SSs. An extraordinarily duplicated VirB6 gene encodes five hydrophobic proteins conserved only in a short region known to be involved in DNA transfer in A. tumefaciens. virB1, virB2 and virB7 are newly identified, revealing a Rickettsia T4SS lacking only virB5 relative to the vir archetype. Phylogeny estimation suggests vertical inheritance of all components, despite gene rearrangements into an archipelago of five islets. Similarities of Rickettsia VirB7/VirB9 to ComB7/ComB9 proteins of epsilon-proteobacteria, as well as phylogenetic affinities to the Legionella lvh T4SS, imply the Rickettsiales ancestor acquired a vir-like locus from distantly related bacteria, perhaps while residing in a protozoan host. Modern modifications of these systems likely reflect diversification with various eukaryotic host cells.We present the rvh (Rickettsiales vir homolog) T4SS, an evolutionary conserved transporter with an unknown role in rickettsial biology. This work lays the foundation for future laboratory characterization of this system, and also identifies the Legionella lvh T4SS as a suitable genetic model
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