177 research outputs found
Acute atrial ischemia associates with early but not late new-onset atrial fibrillation in STEMI patients treated with primary PCI: relationship with in-hospital outcomes
Abstract
Funding Acknowledgements
Type of funding sources: None.
OnBehalf
N/A
Background. New-onset atrial fibrillation (NOAF) is known to be a common complication in STEMI patients undergoing primary percutaneous coronary intervention (PCI), which is associated with a negative short- and long-term prognosis. Recently, two distinct phenotypes of NOAF have been described, namely early (EAF) and late NOAF (LAF). However, whether EAF and LAF recognize different pathogenetic mechanisms is unknown.
Purpose. To investigate atrial branches occlusion and EAF or LAF onset in STEMI patients undergoing primary PCI.
Methods. Retrospective cohort study including 155 STEMI patients. Patients were divided into 3 groups: sinus rhythm (SR), EAF or LAF. Clinical characteristics, angiographic features including occlusion of atrial branches, namely ramus ostia cavae superioris (ROCS), atrio-ventricular node artery (AVNA), right intermediate atrial artery (RIAA) and left intermediate atrial artery (LIAA), were assessed. We also investigated in-hospital complications, death, and a composite of major post-NOAF adverse events (AEs) including cardiogenic shock, acute pulmonary edema, sustained ventricular tachycardia and ventricular fibrillation.
Results. Mean age was 63.8 ± 11.9 years; 78.7% of men. NOAF was detected in 22 (14.2%) patients: 10 (6.4%) EAF and 12 LAF (7.7%). Compared to EAF, LAF patients were older (p = 0.013), with higher GRACE risk score (p = 0.014) and Killip class (p = 0.015), depressed ejection fraction (p = 0.007), elevated filling pressures (p = 0.029), higher c-reactive protein (p = 0.014) and more TIMI flow <3 (p = 0.015). As shown in Figure 1, EAF was associated with higher prevalence of occluded ROCS (p = 0.010), AVNA (p = 0.005) and RIAA (p < 0.001), compared to SR. Moreover, EAF patients had more frequently ≥2 diseased atrial branches than SR (19.5%, p < 0.001) and LAF (25%, p < 0.030) patients. In LAF patients, a higher incidence of pre-PCI cardiogenic shock, post-PCI AEs (p = 0.019 vs SR; p = 0.029 vs EAF) and death (p = 0.004 vs SR) was found.
Conclusions. The occlusion of atrial branches is associated with early but not late NOAF following STEMI. LAF patients had worse in-hospital AEs and mortality. Abstract Figure
Impaired GH Secretion in Patients with SHOX Deficiency and Efficacy of Recombinant Human GH Therapy.
Background/Aims: Mutations of the short stature homeobox-containing (SHOX) gene on the pseudoautosomal region of the sex chromosomes cause short stature. GH treatment has been recently proposed to improve height in short patients with SHOX deficiency. The aim of this study was to evaluate GH secretion and analyze growth and safety of recombinant human GH (rhGH) therapy in short children and adolescents with SHOX deficiency. Patients and Design: We studied 16 patients (10 females; 9.7 ± 2.9 years old; height -2.46 ± 0.82 standard deviation score, SDS) with SHOX deficiency. All subjects underwent auxological evaluations, biochemical investigations, and were treated with rhGH (0.273 ± 0.053 mg/kg/week). Results: Impaired GH secretion was present in 37.5% of the studied subjects. Comparing baseline data with those at the last visit, we found that rhGH treatment improved growth velocity SDS (from -1.03 ± 1.44 to 2.77 ± 1.95; p = 0.001), height SDS (from -2.41 ± 0.71 to -1.81 ± 0.87; p < 0.001), and IGF-1 values (from -0.57 ± 1.23 to 0.63 ± 1.63 SDS, p = 0.010) without affecting body mass index SDS. Height SDS measured at the last visit was significantly correlated with chronological age (r = -0.618, p = 0.032), bone age (r = -0.582, p = 0.047) and height SDS (r = 0.938, p < 0.001) at the beginning of treatment. No adverse events were reported on rhGH therapy which was never discontinued. Conclusion: These data showed that impaired GH secretion is not uncommon in SHOX deficiency subjects, and that rhGH therapy may be effective in increasing height in most of these patients independent of their GH secretory status, without causing any adverse events of concern
Resuscitation Endpoints in Trauma
Fluid and blood resuscitation is the mainstay of therapy for the treatment of hemorrhagic shock, whether due to trauma or other etiology. Cessation of hemorrhage with rapid hemostatic techniques is the first priority in the treatment of traumatic hemorrhagic shock, with concomitant fluid resuscitation with blood and crystalloids to maintain perfusion and organ function. “Hypotensive” or “low-volume” resuscitation has become increasingly accepted in the prehospital resuscitation phase of trauma, prior to definitive hemorrhage control, since aggressive fluid resuscitation may increase bleeding. Resuscitation after hemorrhage control is focused on restoration of tissue oxygenation. Efforts to optimize resuscitation have used “resuscitation endpoints” as markers of adequacy of resuscitation. The resuscitation endpoints that have been evaluated include both global (restoration of blood pressure, heart rate and urine output, lactate, base deficit, mixed venous oxygen saturation, ventricular end-diastolic volume) and regional (gastric tonometry, near-infrared spectroscopy for measurement of muscle tissue oxygen saturation) measures. This review critically evaluates the evidence regarding the use of resuscitation endpoints in trauma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75386/1/j.1778-428X.2005.tb00127.x.pd
An optically stimulated superconducting-like phase in K3C60 far above equilibrium Tc
The control of non-equilibrium phenomena in complex solids is an important
research frontier, encompassing new effects like light induced
superconductivity. Here, we show that coherent optical excitation of molecular
vibrations in the organic conductor K3C60 can induce a non-equilibrium state
with the optical properties of a superconductor. A transient gap in the real
part of the optical conductivity and a low-frequency divergence of the
imaginary part are measured for base temperatures far above equilibrium Tc=20
K. These findings underscore the role of coherent light fields in inducing
emergent order.Comment: 40 pages, 23 figure
Cooling quasiparticles in A(3)C(60) fullerides by excitonic mid-infrared absorption
Long after its discovery, superconductivity in alkali fullerides A(3)C(60) still challenges conventional wisdom. The freshest inroad in such ever-surprising physics is the behaviour under intense infrared excitation. Signatures attributable to a transient superconducting state extending up to temperatures ten times higher than the equilibrium T-c similar to 20 K have been discovered in K3C60 after ultra-short pulsed infrared irradiation-an effect which still appears as remarkable as mysterious. Motivated by the observation that the phenomenon is observed in a broad pumping frequency range that coincides with the mid-infrared electronic absorption peak still of unclear origin, rather than to transverse optical phonons as has been proposed, we advance here a radically new mechanism. First, we argue that this broad absorption peak represents a 'super-exciton' involving the promotion of one electron from the t(1u) half-filled state to a higher-energy empty t(1g) state, dramatically lowered in energy by the large dipole-dipole interaction acting in conjunction with the Jahn-Teller effect within the enormously degenerate manifold of (t(1u))(2)(t(1g))(1) states. Both long-lived and entropy-rich because they are triplets, the infrared-induced excitons act as a sort of cooling mechanism that permits transient superconductive signals to persist up to much higher temperatures
Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors
One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with similar to 90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence.open181
Importance of salt fingering for new nitrogen supply in the oligotrophic ocean.
The input of new nitrogen into the euphotic zone constrains the export of organic carbon to
the deep ocean and thereby the biologically mediated long-term CO2 exchange between
the ocean and atmosphere. In low-latitude open-ocean regions, turbulence-driven nitrate
diffusion from the ocean’s interior and biological fixation of atmospheric N2 are the main
sources of new nitrogen for phytoplankton productivity. With measurements across the
tropical and subtropical Atlantic, Pacific and Indian oceans, we show that nitrate diffusion
(171±190 mmolm 2 d 1) dominates over N2 fixation (9.0±9.4 mmolm 2 d 1) at the time
of sampling. Nitrate diffusion mediated by salt fingers is responsible for ca. 20% of the new
nitrogen supply in several provinces of the Atlantic and Indian Oceans. Our results indicate
that salt finger diffusion should be considered in present and future ocean nitrogen budgets,
as it could supply globally 0.23–1.00 TmolNyr 1 to the euphotic zone.MALASPINA (CSD2008-00077)Versión del editor10,015
Membrane Permeabilization by Oligomeric α-Synuclein: In Search of the Mechanism
Background: \ud
The question of how the aggregation of the neuronal protein α-synuclein contributes to neuronal toxicity in Parkinson's disease has been the subject of intensive research over the past decade. Recently, attention has shifted from the amyloid fibrils to soluble oligomeric intermediates in the α-synuclein aggregation process. These oligomers are hypothesized to be cytotoxic and to permeabilize cellular membranes, possibly by forming pore-like complexes in the bilayer. Although the subject of α-synuclein oligomer-membrane interactions has attracted much attention, there is only limited evidence that supports the pore formation by α-synuclein oligomers. In addition the existing data are contradictory.\ud
\ud
Methodology/Principal Findings:\ud
Here we have studied the mechanism of lipid bilayer disruption by a well-characterized α-synuclein oligomer species in detail using a number of in vitro bilayer systems and assays. Dye efflux from vesicles induced by oligomeric α-synuclein was found to be a fast all-or-none process. Individual vesicles swiftly lose their contents but overall vesicle morphology remains unaltered. A newly developed assay based on a dextran-coupled dye showed that non-equilibrium processes dominate the disruption of the vesicles. The membrane is highly permeable to solute influx directly after oligomer addition, after which membrane integrity is partly restored. The permeabilization of the membrane is possibly related to the intrinsic instability of the bilayer. Vesicles composed of negatively charged lipids, which are generally used for measuring α-synuclein-lipid interactions, were unstable to protein adsorption in general.\ud
\ud
Conclusions/Significance:\ud
The dye efflux from negatively charged vesicles upon addition of α-synuclein has been hypothesized to occur through the formation of oligomeric membrane pores. However, our results show that the dye efflux characteristics are consistent with bilayer defects caused by membrane instability. These data shed new insights into potential mechanisms of toxicity of oligomeric α-synuclein species
- …