The fate of the distal aorta after repair of acute type A aortic dissection

ObjectivesThe residual aorta’s behavior after repair of acute type A dissection is incompletely understood. We analyzed segmental growth rates, distal reoperation, and factors influencing long-term survival.MethodsOne hundred seventy-nine consecutive patients (70% male; mean age, 60 years) with acute type A dissection underwent aggressive resection of the intimal tear and open distal anastomosis (1986-2003). Hospital mortality was 13.4%. Survivors had serial computed tomographic scans: digitization yielded distal segmental dimensions. Segment-specific average rates of enlargement and factors influencing faster growth were analyzed. Distal reoperations and patient survival were examined.ResultsEighty-nine (57%) patients had imaging data sufficient for growth rate calculations. The median diameters after repair were as follows: aortic arch, 3.6 cm; descending aorta, 3.7 cm; and abdominal aorta, 3.2 cm. Subsequent growth rates were 0.8, 1.0, and 0.8 mm/y, respectively. Initial size of greater than 4 cm (P = .005) and initial diameter of less than 4 cm with a patent false lumen (P = .004) predicted greater growth in the descending aorta, and male sex (P = .05) significantly affected growth in the abdominal aorta. No significant factors were found for the aortic arch. There were 25 distal aortic reoperations (16 patients), and risk of reoperation was 16% at 10 years. Risk factors reducing long-term survival after repair of acute type A dissection included age (P < .0001), new neurological deficit at presentation (P = .04), absence of preoperative thrombus in the false lumen of the ascending aorta (P = .03), and a patent distal false lumen postoperatively (P = .06) but not distal reoperation.ConclusionsGrowth of the distal aorta after repair of acute type A dissection is typically slow and linear. Distal reoperation is uncommon, and late risk of death is approximately twice that of a healthy population

Poison, plants and Palaeolithic hunters. An analytical method to investigate the presence of plant poison on archaeological artefacts

In this paper we present the development of a method for the detection of toxic substances on ancient arrow points. The aim is to go back in time until the Palaeolithic period in order to determine if poisonous substances were used to enhance the hunting weapons. The ethnographic documentation demonstrates that hunters of every latitude poisoned their weapons with toxic substances derived from plants and occasionally from animals. This highlights that often the weapons would be rather ineffective if the tips were not poisoned. The fact that toxic substances were available and the benefits arising from their application on throwing weapons, suggests that this practice could be widespread also among prehistoric hunters. The project reviewed the research of the toxic molecules starting from current information on modern plants and working backwards through the ages with the study of ethnographic and historical weapons. This knowledge was then applied to the archaeological material collected from International museum collections. Results have shown that using this method it is possible to detect traces of toxic molecules with mass spectrometry (MS) and hyphenated chromatographic techniques even on samples older than one hundred years, which we consider a positive incentive to continue studying plant poisons on ancient hunting tools

Surplus Carbon Drives Allocation and Plant-Soil Interactions

Plant growth is usually constrained by the availability of nutrients, water, or temperature, rather than photosynthetic carbon (C) fixation. Under these conditions leaf growth is curtailed more than C fixation, and the surplus photosynthates are exported from the leaf. In plants limited by nitrogen (N) or phosphorus (P), photosynthates are converted into sugars and secondary metabolites. Some surplus C is translocated to roots and released as root exudates or transferred to root-associated microorganisms. Surplus C is also produced under low moisture availability, low temperature, and high atmospheric CO2 concentrations, with similar below-ground effects. Many interactions among above- and below-ground ecosystem components can be parsimoniously explained by the production, distribution, and release of surplus C under conditions that limit plant growth.Non peer reviewe

Detection of postoperative granulation tissue with an ICG-enhanced integrated OI-/X-ray System

<p>Abstract</p> <p>Background</p> <p>The development of postoperative granulation tissue is one of the main postoperative risks after lumbar spine surgery. This granulation tissue may lead to persistent or new clinical symptoms or complicate a follow up surgery. A sensitive non-invasive imaging technique, that could diagnose this granulation tissue at the bedside, would help to develop appropriate treatments. Thus, the purpose of this study was to establish a fast and economic imaging tool for the diagnosis of granulation tissue after lumbar spine surgery, using a new integrated Optical Imaging (OI)/X-ray imaging system and the FDA-approved fluorescent contrast agent Indocyanine Green (ICG).</p> <p>Methods</p> <p>12 male Sprague Dawley rats underwent intervertebral disk surgery. Imaging of the operated lumbar spine was done with the integrated OI/X-ray system at 7 and 14 days after surgery. 6 rats served as non-operated controls. OI/X-ray scans of all rats were acquired before and after intravenous injection of the FDA-approved fluorescent dye Indocyanine Green (ICG) at a dose of 1 mg/kg or 10 mg/kg. The fluorescence signal of the paravertebral soft tissues was compared between different groups of rats using Wilcoxon-tests. Lumbar spines and paravertebral soft tissues were further processed with histopathology.</p> <p>Results</p> <p>In both dose groups, ICG provided a significant enhancement of soft tissue in the area of surgery, which corresponded with granulation tissue on histopathology. The peak and time interval of fluorescence enhancement was significantly higher using 10 mg/kg dose of ICG compared to the 1 mg/kg ICG dose. The levels of significance were p < 0.05. Fusion of OI data with X-rays allowed an accurate anatomical localization of the enhancing granulation tissue.</p> <p>Conclusion</p> <p>ICG-enhanced OI is a suitable technique to diagnose granulation tissue after lumbar spine surgery. This new imaging technique may be clinically applicable for postoperative treatment monitoring. It could be also used to evaluate the effect of anti-inflammatory drugs and may even allow evaluations at the bedside with new hand-held OI scanners.</p

Polarization state of the optical near-field

The polarization state of the optical electromagnetic field lying several nanometers above complex dielectric structures reveals the intricate light-matter interaction that occurs in this near-field zone. This information can only be extracted from an analysis of the polarization state of the detected light in the near-field. These polarization states can be calculated by different numerical methods well-suited to near--field optics. In this paper, we apply two different techniques (Localized Green Function Method and Differential Theory of Gratings) to separate each polarisation component associated with both electric and magnetic optical near-fields produced by nanometer sized objects. The analysis is carried out in two stages: in the first stage, we use a simple dipolar model to achieve insight into the physical origin of the near-field polarization state. In the second stage, we calculate accurate numerical field maps, simulating experimental near-field light detection, to supplement the data produced by analytical models. We conclude this study by demonstrating the role played by the near-field polarization in the formation of the local density of states.Comment: 9 pages, 11 figures, accepted for publication in Phys. Rev.

Haemodynamically irrelevant pericardial effusion is associated with increased mortality in patients with chronic heart failure

Aims Pericardial effusion (PE) is a common finding in cardiac patients with chronic heart failure. The prognostic relevance of a small, haemodynamically non-compromising PE in such patients, however, remains to be determined. Methods and results All patients referred to our heart failure clinic and having a baseline echocardiography and follow-up clinical visits were included. Patients with a haemodynamically relevant PE, acute myo-/pericarditis, systemic sclerosis, rheumatoid arthritis, heart transplantation, heart surgery within the last 6 months or malignancies within the last 3 years were excluded. Patients with or without a haemodynamically irrelevant PE were compared regarding all-cause mortality as the primary and cardiovascular death or need for heart transplantation as secondary outcomes. A total of 897 patients (824 patients in the control vs. 73 patients in the PE group) were included. In the PE group, left ventricular ejection fraction (LVEF) was lower [31%, interquartile range (IQR): 18.0-45.0] than in controls (34%, IQR: 25.0-47.0; P = 0.04), while the end-systolic diameters of the left ventricle and the left atrium were larger (P = 0.01 and P = 0.001, respectively). Similarly, in patients with PE, the right ventricle (RV) systolic function was lower (P < 0.005 for both the fractional area change and the tricuspid annulus movement), the dimensions of RV and right atrium (RA) were larger (P < 0.05 for RV and P < 0.01 for RA), and the degree of tricuspid regurgitation was higher (P < 0.0001). Furthermore, in the PE group, the heart rate was higher (P < 0.001) and the leukocyte count as well as CRP values were increased (P = 0.004 and P < 0.0001, respectively); beta-blocker use was less frequent (P = 0.04), while spironolactone use was more frequent (P = 0.03). The overall survival was reduced in the PE group compared with controls (P = 0.02). Patients with PE were more likely to suffer cardiovascular death (1-year estimated event-free survival: 86 ± 5 vs. 95 ± 1%; P = 0.01) and to require heart transplantation (1-year estimated event-free survival: 88 ± 4 vs. 95 ± 1%; P = 0.009). A multivariate Cox proportional hazard model revealed the following independent predictors of mortality: (a) PE (P = 0.04, hazard ratio (HR): 1.95, 95% confidence interval (CI): 1.0-3.7), (b) age (P = 0.04, HR: 1.02, 95% CI: 1.0-1.04) and (c) LVEF <35% (P = 0.03, HR: 1.7, 95% CI: 1.1-2.8). Conclusion In chronic heart failure, even minor PEs are associated with an increased risk of all-cause mortality, cardiac death, and need for transplantatio

Coronary collaterals and risk for restenosis after percutaneous coronary interventions: a meta-analysis

<p>Abstract</p> <p>Background</p> <p>The benefit of the coronary collateral circulation (natural bypass network) on survival is well established. However, data derived from smaller studies indicates that coronary collaterals may increase the risk for restenosis after percutaneous coronary interventions. The purpose of this systematic review and meta-analysis of observational studies was to explore the impact of the collateral circulation on the risk for restenosis.</p> <p>Methods</p> <p>We searched the MEDLINE, EMBASE and ISI Web of Science databases (2001 to 15 July 2011). Random effects models were used to calculate summary risk ratios (RR) for restenosis. The primary endpoint was angiographic restenosis > 50%.</p> <p>Results</p> <p>A total of 7 studies enrolling 1,425 subjects were integrated in this analysis. On average across studies, the presence of a good collateralization was predictive for restenosis (risk ratio (RR) 1.40 (95% CI 1.09 to 1.80); <it>P </it>= 0.009). This risk ratio was consistent in the subgroup analyses where collateralization was assessed with intracoronary pressure measurements (RR 1.37 (95% CI 1.03 to 1.83); <it>P </it>= 0.038) versus visual assessment (RR 1.41 (95% CI 1.00 to 1.99); <it>P </it>= 0.049). For the subgroup of patients with stable coronary artery disease (CAD), the RR for restenosis with 'good collaterals' was 1.64 (95% CI 1.14 to 2.35) compared to 'poor collaterals' (<it>P </it>= 0.008). For patients with acute myocardial infarction, however, the RR for restenosis with 'good collateralization' was only 1.23 (95% CI 0.89 to 1.69); <it>P </it>= 0.212.</p> <p>Conclusions</p> <p>The risk of restenosis after percutaneous coronary intervention (PCI) is increased in patients with good coronary collateralization. Assessment of the coronary collateral circulation before PCI may be useful for risk stratification and for the choice of antiproliferative measures (drug-eluting stent instead bare-metal stent, cilostazol).</p

Assessment of eutrophication abatement scenarios for the Baltic Sea by multi-model ensemble simulations

Peer reviewe

Assessment of Uncertainties in Scenario Simulations of Biogeochemical Cycles in the Baltic Sea

Following earlier regional assessment studies, such as the Assessment of Climate Change for the Baltic Sea Basin and the North Sea Region Climate Change Assessment, knowledge acquired from available literature about future scenario simulations of biogeochemical cycles in the Baltic Sea and their uncertainties is assessed. The identification and reduction of uncertainties of scenario simulations are issues for marine management. For instance, it is important to know whether nutrient load abatement will meet its objectives of restored water quality status in future climate or whether additional measures are required. However, uncertainties are large and their sources need to be understood to draw conclusions about the effectiveness of measures. The assessment of sources of uncertainties in projections of biogeochemical cycles based on authors' own expert judgment suggests that the biggest uncertainties are caused by (1) unknown current and future bioavailable nutrient loads from land and atmosphere, (2) the experimental setup (including the spin up strategy), (3) differences between the projections of global and regional climate models, in particular, with respect to the global mean sea level rise and regional water cycle, (4) differing model-specific responses of the simulated biogeochemical cycles to long-term changes in external nutrient loads and climate of the Baltic Sea region, and (5) unknown future greenhouse gas emissions. Regular assessments of the models' skill (or quality compared to observations) for the Baltic Sea region and the spread in scenario simulations (differences among projected changes) as well as improvement of dynamical downscaling methods are recommended.Peer reviewe

Versatile emulation of spiking neural networks on an accelerated neuromorphic substrate

We present first experimental results on the novel BrainScaleS-2 neuromorphic architecture based on an analog neuro-synaptic core and augmented by embedded microprocessors for complex plasticity and experiment control. The high acceleration factor of 1000 compared to biological dynamics enables the execution of computationally expensive tasks, by allowing the fast emulation of long-duration experiments or rapid iteration over many consecutive trials. The flexibility of our architecture is demonstrated in a suite of five distinct experiments, which emphasize different aspects of the BrainScaleS-2 system