1,176 research outputs found
Meta-analysis of death and myocardial infarction in the DEFINE-FLAIR and iFR-SWEDEHEART trials: a hypothesis generating note of caution
In patients with coronary heart disease, revascularization can improve symptoms and in certain high-risk subgroups may improve prognosis. Coronary angiography provides anatomical information and the physiological significance of a stenosis can be determined using fractional flow reserve (FFR). Decisions on the need for and mode of revascularization can be optimized using FFR, however this involves administering adenosine to induce hyperemia. Generally, this test is well tolerated, but in some healthcare systems adenosine is either not licensed, unavailable, or expensive, limiting the use of FFR-guided management
The debate between postmodernism and historiography: An accounting historianâs manifesto
Garry Carnegie recently concluded that âthe key development in accounting historiography between 1983 and 2012 has been the advent of new accounting historyâ. We agree and believe that the debate in accounting reflects a greater debate between postmodern and traditional historians â one which questions both the nature of historiography and the historianâs role in society. As a participant in this debate, Michael Gaffikin criticized traditionalists (in accounting) for failing to assess developments in the general history literature. This article responds to Gaffikinâs critique. We initially describe the key issues in the debate between postmodern and traditional historians. We review the current general history literature and then recount how the debate played out in three distinct episodes in accounting historiography in which the authors directly participated. We conclude by assessing the current state of accounting historiography
Stretchable Device for Simultaneous Measurements of Contractility and Electrophysiology of Neuromuscular Tissue in the Gastrointestinal Tract.
Devices interfacing with biological tissues can provide valuable insights into function, disease, and metabolism through electrical and mechanical signals. However, certain neuromuscular tissues, like those in the gastrointestinal tract, undergo significant strains of up to 40%. Conventional inextensible devices cannot capture the dynamic responses in these tissues. This study introduces electrodes made from poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and polydimethylsiloxane (PDMS) that enable simultaneous monitoring of electrical and mechanical responses of gut tissue. The soft PDMS layers conform to tissue surfaces during gastrointestinal movement. Dopants, including Capstone FS-30 and polyethylene glycol, are explored to enhance the conductivity, electrical sensitivity to strain, and stability of the PEDOT:PSS. The devices are fabricated using shadow masks and solution-processing techniques, providing a faster and simpler process than traditional clean-room-based lithography. Tested on ex vivo mouse colon and human stomach, the device recorded voltage changes of up to 300 ”V during contraction and distension consistent with muscle activity, while simultaneously recording resistance changes of up to 150% due to mechanical strain. These devices detect and respond to chemical stimulants and blockers, and can induce contractions through electrical stimulation. They hold great potential for studying and treating complex disorders like irritable bowel syndrome and gastroparesis
The relationship between oxidised LDL, endothelial progenitor cells and coronary endothelial function in patients with CHD
Objective The balance between coronary endothelial dysfunction and repair is influenced by many protective and deleterious factors circulating in the blood. We studied the relationship between oxidised low-density lipoprotein (oxLDL), circulating endothelial progenitor cells (EPCs) and coronary endothelial function in patients with stable coronary heart disease (CHD).
Methods 33 patients with stable CHD were studied. Plasma oxLDL was measured using ELISA, coronary endothelial function was assessed using intracoronary acetylcholine infusion and EPCs were quantified using flow cytometry for CD34+/KDR+ cells.
Results Plasma oxLDL correlated positively with the number of EPCs in the blood (r=0.46, p=0.02). There was a positive correlation between the number of circulating EPCs and coronary endothelial function (r=0.42, p=0.04). There was no significant correlation between oxLDL and coronary endothelial function.
Conclusions Plasma levels of oxLDL are associated with increased circulating EPCs in the blood of patients with CHD, which may reflect a host-repair response to endothelial injury. Patients with stable CHD had a high prevalence of coronary endothelial dysfunction, which was associated with lower numbers of circulating EPCs, suggesting a mechanistic link between endothelial dysfunction and the pathogenesis of atherosclerosis
Highly syntenic regions in the genomes of soybean, Medicago truncatula, and Arabidopsis thaliana
BACKGROUND: Recent genome sequencing enables mega-base scale comparisons between related genomes. Comparisons between animals, plants, fungi, and bacteria demonstrate extensive synteny tempered by rearrangements. Within the legume plant family, glimpses of synteny have also been observed. Characterizing syntenic relationships in legumes is important in transferring knowledge from model legumes to crops that are important sources of protein, fixed nitrogen, and health-promoting compounds. RESULTS: We have uncovered two large soybean regions exhibiting synteny with M. truncatula and with a network of segmentally duplicated regions in Arabidopsis. In all, syntenic regions comprise over 500 predicted genes spanning 3 Mb. Up to 75% of soybean genes are colinear with M. truncatula, including one region in which 33 of 35 soybean predicted genes with database support are colinear to M. truncatula. In some regions, 60% of soybean genes share colinearity with a network of A. thaliana duplications. One region is especially interesting because this 500 kbp segment of soybean is syntenic to two paralogous regions in M. truncatula on different chromosomes. Phylogenetic analysis of individual genes within these regions demonstrates that one is orthologous to the soybean region, with which it also shows substantially denser synteny and significantly lower levels of synonymous nucleotide substitutions. The other M. truncatula region is inferred to be paralogous, presumably resulting from a duplication event preceding speciation. CONCLUSION: The presence of well-defined M. truncatula segments showing orthologous and paralogous relationships with soybean allows us to explore the evolution of contiguous genomic regions in the context of ancient genome duplication and speciation events
Nanoparticulate nickel sulfides formed in low temperature aqueous solutions
The nature of the nickel sulfides formed in low temperature
aqueous solutions is not well-understood. The material has some
intrinsic interest to mineralogy, geochemistry and materials science
as well as to biogeochemisty, especially as a possible catalyst
involved in the origin and early evolution of life.
We synthesized Ni sulfide under anoxic conditions at 25 C: (1)
chemically, by the addition of 50 mL of 0.1 M NiSO4Ă7H2O to
100 mL of 0.05M Na2SĂ9H2O; (2) electrochemically, with a Ni
foil and H2S gas. At pH 6 5, millerite (b-NiS) was produced electrochemically
and NiS mixtures, including heazlewoodite (Ni3S2)
and polydymite (Ni3S4), were obtained chemically. At pH >11, a-
NiS was obtained from the chemical reaction. At pH 6â9, the
product produced only two broad peaks (d = ca. 2.7 and 1.8 )
with conventional and synchrotron XRPD which could be
assigned to a number of Ni sulfides. It has previously been
referred to as ââamorphous NiSââ Jeong and Manthiram, 2001.
Eight SAED reflections were collected which identified the material
as godlevskite, orthorhombic NiS. HRTEM shows that the
godlevskite particles are ca. 30 nm in diameter and plate-like.
SAXS analyses show that the material is 6â8.5 nm thick.
Godlevskite is structurally related to makinawite, tetragonal
FeS, and is found naturally in similar parageneses-associated with
the monosulfide solid solution products of high temperature nickel
ores. Mackinawite is the black FeS precipitate from the reaction
between Fe(II) and S(-II) in aqueous solution. It appears that,
geochemically, godlevskite is the Ni analogue of mackinawite
Reducing in-stent restenosis therapeutic manipulation of miRNA in vascular remodeling and inflammation
Background:
Drug-eluting stents reduce the incidence of in-stent restenosis, but they result in delayed arterial healing and are associated with a chronic inflammatory response and hypersensitivity reactions. Identifying novel interventions to enhance wound healing and reduce the inflammatory response may improve long-term clinical outcomes. Microâribonucleic acids (miRNAs) are noncoding small ribonucleic acids that play a prominent role in the initiation and resolution of inflammation after vascular injury.<p></p>
Objectives:
This study sought to identify miRNA regulation and function after implantation of bare-metal and drug-eluting stents.<p></p>
Methods:
Pig, mouse, and in vitro models were used to investigate the role of miRNA in in-stent restenosis.<p></p>
Results:
We documented a subset of inflammatory miRNAs activated after stenting in pigs, including the miR-21 stem loop miRNAs. Genetic ablation of the miR-21 stem loop attenuated neointimal formation in mice post-stenting. This occurred via enhanced levels of anti-inflammatory M2 macrophages coupled with an impaired sensitivity of smooth muscle cells to respond to vascular activation.<p></p>
Conclusions:
MiR-21 plays a prominent role in promoting vascular inflammation and remodeling after stent injury. MiRNA-mediated modulation of the inflammatory response post-stenting may have therapeutic potential to accelerate wound healing and enhance the clinical efficacy of stenting
Diagnostic accuracy of 3.0-T magnetic resonance T1 and T2 mapping and T2-weighted dark-blood imaging for the infarct-related coronary artery in Non-ST-segment elevation myocardial infarction
Background: Patients with recent nonâSTâsegment elevation myocardial infarction commonly have heterogeneous characteristics that may be challenging to assess clinically.
Methods and Results: We prospectively studied the diagnostic accuracy of 2 novel (T1, T2 mapping) and 1 established (T2âweighted short tau inversion recovery [T2WâSTIR]) magnetic resonance imaging methods for imaging the ischemic area at risk and myocardial salvage in 73 patients with nonâSTâsegment elevation myocardial infarction (mean age 57±10 years, 78% male) at 3.0âT magnetic resonance imaging within 6.5±3.5 days of invasive management. The infarctârelated territory was identified independently using a combination of angiographic, ECG, and clinical findings. The presence and extent of infarction was assessed with late gadolinium enhancement imaging (gadobutrol, 0.1 mmol/kg). The extent of acutely injured myocardium was independently assessed with native T1, T2, and T2WâSTIR methods. The mean infarct size was 5.9±8.0% of left ventricular mass. The infarct zone T1 and T2 times were 1323±68 and 57±5 ms, respectively. The diagnostic accuracies of T1 and T2 mapping for identification of the infarctârelated artery were similar (P=0.125), and both were superior to T2WâSTIR (P<0.001). The extent of myocardial injury (percentage of left ventricular volume) estimated with T1 (15.8±10.6%) and T2 maps (16.0±11.8%) was similar (P=0.838) and moderately well correlated (r=0.82, P<0.001). Mean extent of acute injury estimated with T2WâSTIR (7.8±11.6%) was lower than that estimated with T1 (P<0.001) or T2 maps (P<0.001).
Conclusions: In patients with nonâSTâsegment elevation myocardial infarction, T1 and T2 magnetic resonance imaging mapping have higher diagnostic performance than T2WâSTIR for identifying the infarctârelated artery. Compared with conventional STIR, T1 and T2 maps have superior value to inform diagnosis and revascularization planning in nonâSTâsegment elevation myocardial infarction.
Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02073422
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