Procalcitonin Concentration Measured Within the First Days of Cardiac Surgery Is Predictive of Postoperative Infections in Neonates: A Case-Control Study.

Increased procalcitonin concentration (PCT) is known to be reliable for the identification of infections even in the presence of the non-specific systemic inflammatory response seen after cardiopulmonary bypass (CPB), whereas increased C-reactive protein concentration (CRP) is not. The present work explored the ability of neonate PCT measured early after cardiac surgery to identify postoperative infections. This was a retrospective case-control study, where PCT was matched between patients with and without infections according to the patient's age, the CPB length, the use of deep hypothermic circulatory arrest (DHCA), and the postoperative day (POD). The accuracy in the prediction of infections was ascertained and cutoff thresholds were identified. 144 neonates were eligible, and 89 pairs of measurements from 94 patients were analyzed. PCT was a good predictor of infections within POD4, and was a better predictor when compared with CRP at POD1 and POD2. The sum of PCT (pg mL-1) and CRP (mg L-1) > 33 on POD1 or POD2 predicted infections with a 0.68 sensitivity and a 0.82 specificity, and a sum > 49.36 on POD3 or POD4 predicted infections with a 0.82 sensitivity and a 0.93 specificity. In patients with DHCA, PCT was higher than in those without DHCA, and was not predictive of infections. The accuracy of PCT to identify infections after neonatal cardiac surgery is better than that of CRP when measured within 48 h of surgery. The sum of the two markers measured early after surgery is an excellent predictor of postoperative infections.

Atmospheric deposition, CO2, and change in the land carbon sink.

Concentrations of atmospheric carbon dioxide (CO2) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO2 was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO2-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO2, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling.

Evaluating the convergence between eddy-covariance and biometric methods for assessing carbon budgets of forests.

The eddy-covariance (EC) micro-meteorological technique and the ecology-based biometric methods (BM) are the primary methodologies to quantify CO2 exchange between terrestrial ecosystems and the atmosphere (net ecosystem production, NEP) and its two components, ecosystem respiration and gross primary production. Here we show that EC and BM provide different estimates of NEP, but comparable ecosystem respiration and gross primary production for forest ecosystems globally. Discrepancies between methods are not related to environmental or stand variables, but are consistently more pronounced for boreal forests where carbon fluxes are smaller. BM estimates are prone to underestimation of net primary production and overestimation of leaf respiration. EC biases are not apparent across sites, suggesting the effectiveness of standard post-processing procedures. Our results increase confidence in EC, show in which conditions EC and BM estimates can be integrated, and which methodological aspects can improve the convergence between EC and BM.

Fertile forests produce biomass more efficiently.

Trees with sufficient nutrition are known to allocate carbon preferentially to aboveground plant parts. Our global study of 49 forests revealed an even more fundamental carbon allocation response to nutrient availability: forests with high-nutrient availability use 58 ± 3% (mean ± SE; 17 forests) of their photosynthates for plant biomass production (BP), while forests with low-nutrient availability only convert 42 ± 2% (mean ± SE; 19 forests) of annual photosynthates to biomass. This nutrient effect largely overshadows previously observed differences in carbon allocation patterns among climate zones, forest types and age classes. If forests with low-nutrient availability use 16 ± 4% less of their photosynthates for plant growth, what are these used for? Current knowledge suggests that lower BP per unit photosynthesis in forests with low- versus forests with high-nutrient availability reflects not merely an increase in plant respiration, but likely results from reduced carbon allocation to unaccounted components of net primary production, particularly root symbionts.

Aprotinin, transfusions, and kidney injury in neonates and infants undergoing cardiac surgery.

BACKGROUND: A significantly increased risk of acute kidney injury (AKI) with the prophylactic use of aprotinin has been reported in adults undergoing cardiac surgery, but not in children. Blood product transfusions have also been shown to carry an independent risk of AKI. The present study assessed associations between AKI, aprotinin, and transfusions in neonates and infants undergoing cardiac surgery. METHODS: All neonates and infants undergoing surgery with cardiopulmonary bypass over a 42 month period, before and after the withdrawal of aprotinin, were included retrospectively. AKI was assessed by the Acute-Kidney-Injury-Network classifications. A propensity score was used to balance treated and untreated groups. RESULTS: Three hundred and ninety patients received aprotinin and 568 patients did not. Inverse probability of treatment weighting resulted in good balance between groups for baseline and surgical characteristics. Controls underwent surgery with smaller bypass circuits and fewer transfusions. After adjustment for the use of miniaturized circuits and for the year of surgery, no significant association between the incidence of AKI, dialysis, and aprotinin was noted. Red blood cell transfusions were associated with an increased risk of AKI and dialysis: odds ratios (ORs) 1.64 (1.12-2.41) and 2.07 (1.13-3.73), respectively; as were fresh frozen plasma transfusions, ORs 2.28 (1.68-3.09) and 3.11 (1.95-4.97), respectively. Platelet transfusions were associated with an increased risk of dialysis: OR 2.20 (1.21-4.01). CONCLUSIONS: Blood product transfusions, but not the prophylactic use of aprotinin, are significantly associated with AKI after cardiac surgery in neonates and infants.

Temperature dependence of greenhouse gas emissions from three hydromorphic soils at different groundwater levels.

Wetlands contribute considerably to the global greenhouse gas (GHG) balance. In these ecosystems, groundwater level (GWL) and temperature, two factors likely to be altered by climate change, exert important control over CO(2), CH(4) and N(2)O fluxes. However, little is known about the temperature sensitivity (Q(10)) of the combined GHG emissions from hydromorphic soils and how this Q(10) varies with GWL. We performed a greenhouse experiment in which three different (plant-free) hydromorphic soils from a temperate spruce forest were exposed to two GWLs (an intermediate GWL of -20 cm and a high GWL of -5 cm). Net CO(2), CH(4) and N(2)O fluxes were measured continuously. Here, we discuss how these fluxes responded to synoptic temperature fluctuations. Across all soils and GWLs, CO(2) emissions responded similarly to temperature and Q(10) was close to 2. The Q(10) of the CH(4) and N(2)O fluxes also was similar across soil types. GWL, on the other hand, significantly affected the Q(10) of both CH(4) and N(2)O emissions. The Q(10) of the net CH(4) fluxes increased from about 1 at GWL = -20 cm to 3 at GWL = -5 cm. For the N(2)O emissions, Q(10) varied around 2 for GWL = -20 cm and around 4 for GWL = -5 cm. This substantial GWL-effect on the Q(10) of CH(4) and N(2)O emissions was, however, hardly reflected in the Q(10) of the total GHG emissions (which varied around 2), because the contribution of these gases was relatively small compared to that of CO(2).

Caspase-dependent apoptosis in THP-1 cells exposed to oxidized low-density lipoproteins.

Oxidized low-density lipoproteins (oxLDL) play a critical role in atherogenesis. We investigated the apoptotic process in human monocytic THP-1 cell line, exposed to oxLDL generated by treatment of native LDL either with hypochlorous acid (HOCl), mainly affecting the protein moiety, or with copper sulfate (CuSO(4)), mainly affecting the lipid moiety. After incubation with both types of oxLDL, we observed: (i) microscopy signs of apoptosis in THP-1 cells, (ii) a significant increase of apoptotic cells proportional to LDL protein concentration, either by annexin V or by cell cycle phase analysis with propodium iodide flow cytometry, (iii) a reduction of THP-1 cell apoptosis in presence of the caspase inhibitor Z-VAD.fmk, (iv) the resistance of THP-1 cells apoptosis after PMA-elicited differentiation. In conclusion, HOCl-oxLDL are as potent as Cu-oxLDL to induce high rates of apoptosis in monocytes through a caspase-dependent pathway. Moreover, the resistance of differentiated THP-1 cells to oxLDL-induced apoptosis is compatible with the hypothesis that mature macrophages have prolonged survival and thereby enhance the atherogenic process.