Microbial methane cycling in sediments of Arctic thermokarst lagoons

Thermokarst lagoons represent the transition state from a freshwater lacustrine to a marine environment, and receive little attention regarding their role for greenhouse gas production and release in Arctic permafrost landscapes. We studied the fate of methane (CH4) in sediments of a thermokarst lagoon in comparison to two thermokarst lakes on the Bykovsky Peninsula in northeastern Siberia through the analysis of sediment CH4 concentrations and isotopic signature, methane-cycling microbial taxa, sediment geochemistry, lipid biomarkers, and network analysis. We assessed how differences in geochemistry between thermokarst lakes and thermokarst lagoons, caused by the infiltration of sulfate-rich marine water, altered the microbial methane-cycling community. Anaerobic sulfate-reducing ANME-2a/2b methanotrophs dominated the sulfate-rich sediments of the lagoon despite its known seasonal alternation between brackish and freshwater inflow and low sulfate concentrations compared to the usual marine ANME habitat. Non-competitive methylotrophic methanogens dominated the methanogenic community of the lakes and the lagoon, independent of differences in porewater chemistry and depth. This potentially contributed to the high CH4 concentrations observed in all sulfate-poor sediments. CH4 concentrations in the freshwater-influenced sediments averaged 1.34 ± 0.98 μmol g−1, with highly depleted δ13C-CH4 values ranging from −89‰ to −70‰. In contrast, the sulfate-affected upper 300 cm of the lagoon exhibited low average CH4 concentrations of 0.011 ± 0.005 μmol g−1 with comparatively enriched δ13C-CH4 values of −54‰ to −37‰ pointing to substantial methane oxidation. Our study shows that lagoon formation specifically supports methane oxidizers and methane oxidation through changes in pore water chemistry, especially sulfate, while methanogens are similar to lake conditions

The role of bioimpedance analysis in overweight and obese patients with acute heart failure: a pilot study.

AIMS Residual congestion at the time of hospital discharge is an important readmission risk factor, and its detection with physical examination and usual diagnostic techniques have strong limitations in overweight and obese patients. New tools like bioelectrical impedance analysis (BIA) could help to determine when euvolaemia is reached. The aim of this study was to investigate the usefulness of BIA in management of heart failure (HF) in overweight and obese patients. METHODS AND RESULTS Our study is a single-centre, single-blind, randomized controlled trial that included 48 overweight and obese patients admitted for acute HF. The study population was randomized into two arms: BIA-guided group and standard care. Serum electrolytes, kidney function, and natriuretic peptides were followed up during their hospital stay and at 90 days after discharge. The primary endpoint was development of severe acute kidney injury (AKI) defined as an increase in serum creatinine by >0.5 mg/dL during hospitalization, and the main secondary endpoint was the reduction of N-terminal pro-brain natriuretic peptide (NT-proBNP) levels during hospitalization and within 90 days after discharge. The BIA-guided group showed a remarkable lower incidence of severe AKI, although no significant differences were found (41.4% vs. 16.7%; P = 0.057). The proportion of patients who achieved levels of NT-proBNP < 1000 pg/mL at 90 days was significantly higher in the BIA-guided group than in the standard group (58.8% vs. 25%; P = 0.049). No differences were observed in the incidence of adverse outcomes at 90 days. CONCLUSIONS Among overweight and obese patients with HF, BIA reduces NT-proBNP levels at 90 days compared with standard care. In addition, there is a trend towards lower incidence of AKI in the BIA-guided group. Although more studies are required, BIA could be a useful tool in decompensated HF management in overweight and obese patients.This research received no external funding.S

Mcp-1 predicts recurrent cardiovascular events in patients with persistent inflammation

Clinical data indicate that patients with C-reactive protein (CRP) levels higher than 2 mg per liter suffer from persistent inflammation, which is associated with high risk of cardiovascular disease (CVD). We determined whether a panel of biomarkers associated with CVD could predict recurrent events in patients with low or persistent inflammation and coronary artery disease (CAD). We followed 917 patients with CAD (median 4.59 ± 2.39 years), assessing CRP, galectin-3, monocyte chemoattractant protein-1 (MCP-1), N-terminal fragment of brain natriuretic peptide (NT-proBNP) and troponin-I plasma levels. The primary outcome was the combination of cardiovascular events (acute coronary syndrome, stroke or transient ischemic event, heart failure or death). Patients with persistent inflammation (n = 343) showed higher NT-proBNP and MCP-1 plasma levels compared to patients with CRP &lt; 2 mg/L. Neither MCP-1 nor NT-proBNP was associated with primary outcome in patients with CRP &lt; 2 mg/L. However, NT-proBNP and MCP-1 plasma levels were associated with increased risk of the primary outcome in patients with persistent inflammation. When patients were divided by type of event, MCP-1 was associated with an increased risk of acute ischemic events. A significant interaction between MCP-1 and persistent inflammation was found (synergy index: 6.17 (4.39–7.95)). In conclusion, MCP-1 plasma concentration is associated with recurrent cardiovascular events in patients with persistent inflammation.This research was funded by grants from Fondo de Investigaciones Sanitarias (PI14/1567, PI05/0451, PI16/01419, PI17/01615, PI17/01495, PI19/00128); RETOS-Colaboración (RTC2019-006826-1); Spanish Society of Arteriosclerosis; and Instituto de Salud Carlos III FEDER (FJD biobank: RD09/0076/00101

Non-coronary atherosclerosis: a marker of poor prognosis in patients undergoing coronary artery bypass surgery

IntroductionThe presence of non-coronary atherosclerosis (NCA) in patients with coronary artery disease is associated with a poor prognosis. We have studied whether NCA is also a predictor of poorer outcomes in patients undergoing coronary artery bypass grafting (CABG).Materials and methodsThis is an observational study involving 567 consecutive patients who underwent CABG. Variables and prognosis were analysed based on the presence or absence of NCA, defined as previous stroke, transient ischaemic attack (TIA), or peripheral artery disease (PAD) [lower extremity artery disease (LEAD), carotid disease, previous lower limb vascular surgery, or abdominal aortic aneurysm (AAA)]. The primary outcome was a combination of TIA/stroke, acute myocardial infarction, new revascularization procedure, or death. The secondary outcome added the need for LEAD revascularization or AAA surgery.ResultsOne-hundred thirty-eight patients (24%) had NCA. Among them, traditional cardiovascular risk factors and older age were more frequently present. At multivariate analysis, NCA [hazard ratio (HR) = 1.84, 95% confidence interval (CI) 1.27–2.69], age (HR = 1.35, 95% CI 1.09–1.67, p = 0.004), and diabetes mellitus (HR = 1.50, 95% CI 1.05–2.15, p = 0.025), were positively associated with the development of the primary outcome, while estimated glomerular filtration rate (HR = 0.86, 95% CI 0.80–0.93, p = 0.001) and use of left internal mammary artery (HR = 0.36, 95% CI 0.15–0.82, p = 0.035), were inversely associated with this outcome. NCA was also an independent predictor of the secondary outcome. Mortality was also higher in NCA patients (27.5% vs. 9%, p &lt; 0.001).ConclusionsAmong patients undergoing CABG, the presence of NCA doubled the risk of developing cardiovascular events, and it was associated with higher mortality

Subseafloor sedimentary life in the South Pacific Gyre

The low-productivity South Pacific Gyre (SPG) is Earth's largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1–1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths in all previously explored subseafloor communities. The net rate of respiration by the subseafloor sedimentary community at each SPG site is 1 to 3 orders of magnitude lower than the rates at previously explored sites. Because of the low respiration rates and the thinness of the sediment, interstitial waters are oxic throughout the sediment column in most of this region. Consequently, the sedimentary community of the SPG is predominantly aerobic, unlike previously explored subseafloor communities. Generation of H2 by radiolysis of water is a significant electron-donor source for this community. The per-cell respiration rates of this community are about 2 orders of magnitude higher (in oxidation/reduction equivalents) than in previously explored anaerobic subseafloor communities. Respiration rates and cell concentrations in subseafloor sediment throughout almost half of the world ocean may approach those in SPG sediment

Absence of High Lipoprotein(a) Levels Is an Independent Predictor of Acute Myocardial Infarction without Coronary Lesions

The pathophysiological mechanisms underlying Myocardial Infarction with Non-Obstructive Coronary Artery Disease (MINOCA) are still under debate. Lipoprotein (a) [Lp(a)] has proinflammatory and prothrombotic actions and has been involved in the pathogenesis of atherosclerosis. However, no previous studies have linked Lp(a) levels with the probability of developing MINOCA. Moreover, the relationship between MINOCA and the plasma levels of other proatherogenic and proinflammatory molecules such as Interleukin-18 (IL18) and proprotein convertase subtilisin/kexin type 9 (PCSK9) has not been studied. We conducted a prospective, multicenter study involving 1042 patients with acute myocardial infarction (AMI). Seventy-six patients had no significant coronary lesions. All patients underwent plasma analysis on admission. MINOCA patients were younger (57 (47&ndash;68) vs. 61 (52&ndash;72) years; p = 0.010), more frequently female (44.7% vs. 21.0%; p &lt; 0.001), and had lower rates of diabetes and of Lp(a) &gt; 60 mg/dL (9.2% vs. 19.8%; p = 0.037) than those with coronary lesions; moreover, High Density Lipoprotein cholesterol (HDL-c) levels were higher in MINOCA patients. The absence of Lp(a) &gt; 60 mg/dL and of diabetes were independent predictors of MINOCA, as well as female sex, high HDL-c levels, and younger age. IL-18 and PCSK9 levels were not predictors of MINOCA. During a follow-up of 5.23 (2.89, 7.37) years, the independent predictors of the primary outcome (acute ischemic events or death) in the whole sample were Lp(a) &gt; 60 mg/dL, older age, low estimated Glomerular Filtration rate (eGFR), hypertension, previous heart failure (HF), coronary artery bypass graft, use of insulin, and no therapy with acetylsalicylic acid. In conclusion, in AMI patients, the absence of high Lp(a) levels, as well high HDL-c levels, were independent predictors of the inexistence of coronary artery disease. High Lp (a) levels were also an independent predictor of ischemic events or death

Galectin-3 is Associated with Cardiovascular Events in Post-Acute Coronary Syndrome Patients with Type-2 Diabetes

Introduction: Type-2 diabetes mellitus (T2DM) is associated with early and severe atherosclerosis. However, few biomarkers can predict cardiovascular events in this population. Methods: We followed 964 patients with coronary artery disease (CAD), assessing plasma levels of galectin-3, monocyte chemoattractant protein-1 (MCP-1), and N-terminal fragment of brain natriuretic peptide (NT-proBNP) at baseline. The secondary outcomes were acute ischemia and heart failure or death. The primary outcome was the combination of the secondary outcomes. Results. Two hundred thirty-two patients had T2DM. Patients with T2DM showed higher MCP-1 (144 (113&ndash;195) vs. 133 (105&ndash;173) pg/mL, p = 0.006) and galectin-3 (8.3 (6.5&ndash;10.5) vs. 7.8 (5.9&ndash;9.8) ng/mL, p = 0.049) levels as compared to patients without diabetes. Median follow-up was 5.39 years (2.81&ndash;6.92). Galectin-3 levels were associated with increased risk of the primary outcome in T2DM patients (Hazard ratio (HR) 1.57 (1.07&ndash;2.30); p = 0.022), along with a history of cerebrovascular events. Treatment with clopidogrel was associated with lower risk. In contrast, NT-proBNP and MCP-1, but not galectin-3, were related to increased risk of the event in nondiabetic patients (HR 1.21 (1.04&ndash;1.42); p = 0.017 and HR 1.23 (1.05&ndash;1.44); p = 0.012, respectively), along with male sex and age. Galectin-3 was also the only biomarker associated with the development of acute ischemic events and heart failure or death in T2DM patients, while, in nondiabetics, MCP-1 and NT-proBNP, respectively, were related to these events. Conclusion: In CAD patients, galectin-3 plasma levels are associated with cardiovascular events in patients with T2DM, and MCP-1 and NT-proBNP in those without T2DM

Heterogeneous knowledge: Trends in German discourse analysis against an international background

This contribution maps the complex field of discourse analysis in Germany by situating its major currents and putting them in historical perspective. In a first step, it presents the major intellectual sources, such as (post-)structuralism, pragmatism/interactionism as well as hermeneutics, which have served as a backdrop for the establishment of discourse analysis as an interdisciplinary field since the 1980s. In a second step, it takes a closer look at the intellectual conjunctures in the social sciences such as Critical Theory and systems theory before turning to the discourse analytical tendencies that have emerged since the 1980s in the light of Foucault's reception in Germany. Finally, it discusses the features of heterogeneous knowledge discourses. As against top-down studies of political discourse in France and bottom-up investigations of everyday discourse in the US, many discourse analysts in Germany focus on knowledge production as a multi-leveled process involving texts and contexts. Therefore, discourse is seen as a heterogeneous object constructed in the interplay of language, praxis and knowledge