Trust in numbers: Serious numbers and speculative fictions in rare earth elements exploration.

In the early 2010s, a spectacular fall in prices for a class of mineral commodities called the rare earth elements (REEs) and the collapse of hundreds of new exploration companies made clear the fragility of the high-risk markets around these companies and the strategies of legitimation that supported them. New regulatory processes built around technical disclosures generated vast stores of geotechnical data. Rather than generating trust among market actors, however, these processes dramatically altered the temporalities of global extraction and energized unruly narrative spaces. In their efforts to keep mineral claims active and companies afloat, REE-focused exploration experts have struggled to navigate different arenas of discussion while holding their respective logics in tension. Drawing on ethnographic fieldwork with exploration geologists and promoters, this article examines how experts federate flows of 'serious' and 'speculative' information in both carefully regulated reports and rumor-filled online forums. Such spaces are organized by aesthetic conventions and social criteria for establishing persuasiveness-forms that STS scholars have long analyzed as literary technologies. Rather than helping to secure experts' authority, however, I argue that the diverse literary technologies that now dominate exploration promotion and finance work have radically redistributed interpretive roles. In their struggles to mediate senses of 'crisis' endemic within venture markets, exploration experts must enact the ideals undergirding new regulatory requirements even as they learn to defer to the speculative musings of others.

Endovascular interventions in outpatient care.

Endovascular arterial revascularisations for the treatment of symptomatic peripheral arterial disease are constantly increasing in importance and number due to the changing age structure and high numbers of comorbidities in the German population. Patients with peripheral artery disease are often at increased risk for peri- and post-procedural complications including severe cardiovascular events. Due to limited financial and human resources and considerable risks of hospitalization, endovascular interventions that were previously reserved for hospitalized patients are now progressively considered to be performed as day case procedures. More than one third of these procedures are performed in Germany by internists with a specialization in angiology. In the current position paper the German Society of Angiology endorsed by the European Society of Vascular Medicine, summarizes the requirements and risk factors to be considered for the planning, safe performance and post procedural care of endovascular revascularizations in outpatients. The performance of endovascular procedures for peripheral artery disease both in hospitalised and outpatients should be accompanied by a mandatory quality assurance process that should not only capture procedural data, but also require documentation of complications and longterm outcome.

Boron-Based Inhibitors of the NLRP3 Inflammasome.

NLRP3 is a receptor important for host responses to infection, yet is also known to contribute to devastating diseases such as Alzheimer's disease, diabetes, atherosclerosis, and others, making inhibitors for NLRP3 sought after. One of the inhibitors currently in use is 2-aminoethoxy diphenylborinate (2APB). Unfortunately, in addition to inhibiting NLRP3, 2APB also displays non-selective effects on cellular Ca2+ homeostasis. Here, we use 2APB as a chemical scaffold to build a series of inhibitors, the NBC series, which inhibit the NLRP3 inflammasome in vitro and in vivo without affecting Ca2+ homeostasis. The core chemical insight of this work is that the oxazaborine ring is a critical feature of the NBC series, and the main biological insight the use of NBC inhibitors led to was that NLRP3 inflammasome activation was independent of Ca2+. The NBC compounds represent useful tools to dissect NLRP3 function, and may lead to oxazaborine ring-containing therapeutics.

Mechanisms Underlying Interferon-γ-Induced Priming of Microglial Reactive Oxygen Species Production.

Microglial priming and enhanced reactivity to secondary insults cause substantial neuronal damage and are hallmarks of brain aging, traumatic brain injury and neurodegenerative diseases. It is, thus, of particular interest to identify mechanisms involved in microglial priming. Here, we demonstrate that priming of microglia with interferon-γ (IFN γ) substantially enhanced production of reactive oxygen species (ROS) following stimulation of microglia with ATP. Priming of microglial ROS production was substantially reduced by inhibition of p38 MAPK activity with SB203580, by increases in intracellular glutathione levels with N-Acetyl-L-cysteine, by blockade of NADPH oxidase subunit NOX2 activity with gp91ds-tat or by inhibition of nitric oxide production with L-NAME. Together, our data indicate that priming of microglial ROS production involves reduction of intracellular glutathione levels, upregulation of NADPH oxidase subunit NOX2 and increases in nitric oxide production, and suggest that these simultaneously occurring processes result in enhanced production of neurotoxic peroxynitrite. Furthermore, IFNγ-induced priming of microglial ROS production was reduced upon blockade of Kir2.1 inward rectifier K+ channels with ML133. Inhibitory effects of ML133 on microglial priming were mediated via regulation of intracellular glutathione levels and nitric oxide production. These data suggest that microglial Kir2.1 channels may represent novel therapeutic targets to inhibit excessive ROS production by primed microglia in brain pathology.

Fenamate NSAIDs inhibit the NLRP3 inflammasome and protect against Alzheimer's disease in rodent models.

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase-1 (COX-1) and COX-2 enzymes. The NLRP3 inflammasome is a multi-protein complex responsible for the processing of the proinflammatory cytokine interleukin-1ß and is implicated in many inflammatory diseases. Here we show that several clinically approved and widely used NSAIDs of the fenamate class are effective and selective inhibitors of the NLRP3 inflammasome via inhibition of the volume-regulated anion channel in macrophages, independently of COX enzymes. Flufenamic acid and mefenamic acid are efficacious in NLRP3-dependent rodent models of inflammation in air pouch and peritoneum. We also show therapeutic effects of fenamates using a model of amyloid beta induced memory loss and a transgenic mouse model of Alzheimer's disease. These data suggest that fenamate NSAIDs could be repurposed as NLRP3 inflammasome inhibitors and Alzheimer's disease therapeutics.

Microglial Kv1.3 Channels and P2Y12 Receptors Differentially Regulate Cytokine and Chemokine Release from Brain Slices of Young Adult and Aged Mice.

Brain tissue damage following stroke or traumatic brain injury is accompanied by neuroinflammatory processes, while microglia play a central role in causing and regulating neuroinflammation via production of proinflammatory substances, including cytokines and chemokines. Here, we used brain slices, an established in situ brain injury model, from young adult and aged mice to investigate cytokine and chemokine production with particular focus on the role of microglia. Twenty four hours after slice preparation, higher concentrations of proinflammatory cytokines, i.e. TNF-α and IL-6, and chemokines, i.e. CCL2 and CXCL1, were released from brain slices of aged mice than from slices of young adult mice. However, maximal microglial stimulation with LPS for 24 h did not reveal age-dependent differences in the amounts of released cytokines and chemokines. Mechanisms underlying microglial cytokine and chemokine production appear to be similar in young adult and aged mice. Inhibition of microglial Kv1.3 channels with margatoxin reduced release of IL-6, but not release of CCL2 and CXCL1. In contrast, blockade of microglial P2Y12 receptors with PSB0739 inhibited release of CCL2 and CXCL1, whereas release of IL-6 remained unaffected. Cytokine and chemokine production was not reduced by inhibitors of Kir2.1 K+ channels or adenosine receptors. In summary, our data suggest that brain tissue damage-induced production of cytokines and chemokines is age-dependent, and differentially regulated by microglial Kv1.3 channels and P2Y12 receptors.

Sonography of subcutaneous tissue cannot determine causes of lower limb edema.

BACKGROUND: To clarify the clinical use of sonography for differentiation of edema we tried to answer the question whether a group of doctors can differentiate lymphedema from cardiac, hepatic or venous edema just by analysing sonographic images of the edema. PATIENTS AND METHODS: 38 (70 ± 12 years, 22 (58 %) females) patients with lower limb edema were recruited according the clinical diagnosis: 10 (26 %) lymphedema, 16 (42 %) heart insufficiency, 6 (16 %) venous disorders, 6 (16 %) chronic hepatic disease. Edema was depicted sonographically at the most affected leg in a standardised way at distal and proximal calf. 38 sets of images were anonymised and send to 5 experienced doctors. They were asked whether they can see criteria for lymphedema: 1. anechoic gaps, 2. horizontal gaps and 3. echoic rims. RESULTS: Accepting an edema as lymphedema if only one doctor sees at least one of the three criteria for lymphatic edema on each single image all edema would be classified as lymphatic. Accepting lymphedema only if all doctors see at least one of the three criteria on the distal image of the same patient 80 % of the patients supposed to have lymphedema are classified as such, but also the majority of cardiac, venous and hepatic edema. Accepting lymphedema only if all doctors see all three criteria on the distal image of the same patients no edema would be classified as lymphatic. In addition we separated patients by Stemmers’ sign in those with positive and negative sign. The interpretation of the images was not different between both groups. CONCLUSIONS: Our analysis shows that it is not possible to differentiate lymphedema from other lower limb edema sonographically.

Microglial K(+) channel expression in young adult and aged mice.

The K(+) channel expression pattern of microglia strongly depends on the cells' microenvironment and has been recognized as a sensitive marker of the cells' functional state. While numerous studies have been performed on microglia in vitro, our knowledge about microglial K(+) channels and their regulation in vivo is limited. Here, we have investigated K(+) currents of microglia in striatum, neocortex and entorhinal cortex of young adult and aged mice. Although almost all microglial cells exhibited inward rectifier K(+) currents upon membrane hyperpolarization, their mean current density was significantly enhanced in aged mice compared with that determined in young adult mice. Some microglial cells additionally exhibited outward rectifier K(+) currents in response to depolarizing voltage pulses. In aged mice, microglial outward rectifier K(+) current density was significantly larger than in young adult mice due to the increased number of aged microglial cells expressing these channels. Aged dystrophic microglia exhibited outward rectifier K(+) currents more frequently than aged ramified microglia. The majority of microglial cells expressed functional BK-type, but not IK- or SK-type, Ca(2+) -activated K(+) channels, while no differences were found in their expression levels between microglia of young adult and aged mice. Neither microglial K(+) channel pattern nor K(+) channel expression levels differed markedly between the three brain regions investigated. It is concluded that age-related changes in microglial phenotype are accompanied by changes in the expression of microglial voltage-activated, but not Ca(2+) -activated, K(+) channels.

TRPM7 regulates proliferation and polarisation of macrophages.

Ion channels play pivotal roles in regulating important functions of macrophages, such as cytokine and chemokine production, migration, proliferation, phagocytosis and others. In this study, we have identified the transient receptor potential cation channel, subfamily M, member 7 (TRPM7) for the first time in macrophages. TRPM7 activity is differentially regulated in macrophages, i.e. current density in TRPM7 is significantly larger in anti-inflammatory M2-type macrophages than in untreated and in pro-inflammatory M1-type macrophages, whereas mRNA levels of TRPM7 remain unchanged upon cell polarisation. The specific TRPM7 inhibitors NS8593 and FTY720 abolish proliferation of macrophages induced by interleukin-4 (IL-4) and macrophage colony-stimulating factor (M-CSF), respectively, whereas proliferation arrest was not accompanied by induction of apoptosis or necrosis in macrophages. Furthermore, NS8593 and FTY720 prevented polarisation of macrophages towards the anti-inflammatory M2 phenotype. Inhibition of TRPM7 reduced IL-4-induced upregulation of arginase-1 (Arg1) mRNA levels and Arg1 activity, and abolished the inhibitory effects of IL-4 or M-CSF on LPS-induced TNF-α production by macrophages. In summary, our data suggest a main role of TRPM7 in the regulation of macrophage proliferation and polarisation.

The perioperative management of treatment with anticoagulants and platelet aggregation inhibitors.

BACKGROUND: When giving anticoagulants and inhibitors of platelet aggregation either prophylactically or therapeutically, physicians face the challenge of protecting patients from thromboembolic events without inducing harmful bleeding. Especially in the perioperative period, the use of these drugs requires a carefully balanced evaluation of their risks and benefits. Moreover, the choice of drug is difficult, because many different substances have been approved for clinical use. METHOD: We selectively searched for relevant publications that appeared from 2003 to February 2013, with particular consideration of the guidelines of the European Society of Cardiology, the Association of Scientific Medical Societies in Germany (AWMF), the American College of Cardiology, and the American Heart Association. RESULTS: Vitamin K antagonists (VKA), low molecular weight heparins, and fondaparinux are the established anticoagulants. The past few years have seen the introduction of orally administered selective inhibitors of the clotting factors IIa (dabigatran) and Xa (rivaroxaban, apixaban). The timing of perioperative interruption of anticoagulation is based on pharmacokinetic considerations rather than on evidence from clinical trials. Recent studies have shown that substituting short-acting anticoagulants for VKA before a procedure increases the risk of bleeding without lowering the risk of periprocedural thromboembolic events. The therapeutic spectrum of acetylsalicylic acid and clopidogrel has been broadened by the newer platelet aggregation inhibitors prasugrel and ticagrelor. Patients with drug eluting stents should be treated with dual platelet inhibition for 12 months because of the risk of in-stent thrombosis. CONCLUSION: Anticoagulants and platelet aggregation inhibitors are commonly used drugs, but the evidence for their perioperative management is limited. The risks of thrombosis and of hemorrhage must be balanced against each other in the individual case. Anticoagulation need not be stopped for minor procedures.

Uranium, geoinformatics, and the economic image of mineral exploration.

When uranium prospectors working in northern Canada want to visualize a new deposit, they can't simply walk outside and take a picture of the ground beneath their feet. 'Mapping' an ore body in the twenty-first century means building a statistical model from a grid of chemical data, a collaborative process demanding the efforts of drilling crews, geologists, chemists, and statisticians. As rock samples are translated into numerical concentration values and then back into images of geological features, scientific theories become economic data, reshaping geological theory, environmental regulation and development in the process.

Fluorescence imaging of intracellular Ca2+, Na+, and H+ in cultured microglia.

The behavior of microglial cells involves the activity of a variety of ion channels and ion transporters, which are implicated in the regulation of ion concentrations, membrane potential, and cell volume of microglia. Fluorescence imaging has been proven to be an elegant method to study ion concentration changes in intact microglial cells under physiological and pathophysiological conditions. The development of highly specific ion indicators has made it possible to detect changes in intracellular Ca(2+), Na(+), and H(+) concentrations of microglial cells as a result of ion channel or ion transporter activity. Fluorescence signals of isolated dye-loaded microglial cells can be detected via a CCD camera equipped to a conventional microscope. This chapter summarizes protocols of loading of microglial cells with small-molecule ion indicators as well as protocols optimal for measurement and analysis of intracellular Ca(2+), Na(+), and H(+) concentrations in microglia in vitro.

Patch clamp protocols to study ion channel activity in microglia.

Microglia express a variety of ion channels, which can be distinguished based on their ion selectivity into K(+), H(+), Na(+), Ca(2+), nonselective cation, and Cl(-) channels. With respect to their activation mode, voltage-, Ca(2+)-, calcium release-, G protein-, swelling-, and stretch-activated ion channels have been described in microglia. The best method to study the activity of microglial ion channels is the patch clamp technique. The activity of microglial ion channels under physiological conditions is best explored using the perforated patch clamp technique, which allows recordings of membrane potential or ion currents, while the intracellular milieu of the cells remains intact. In whole-cell patch clamp recordings, application of specific voltage protocols with defined intra- and extracellular solutions allows precise identification of a certain ion channel type in microglia as well as the investigation of the channel's biophysical and pharmacological properties. This chapter summarizes patch clamp protocols optimal for recording and analysis of microglial ion channel activity in vitro and in situ.

Amyloid-ß-induced reactive oxygen species production and priming are differentially regulated by ion channels in microglia.

Production of reactive oxygen species (ROS) by microglial cells and subsequent oxidative stress are strongly implicated in the pathogenesis of Alzheimer's disease. Although it is recognized that amyloid-ß (Aß) plays a major role in inducing and regulating microglial ROS production in Alzheimer's disease, to date little is known about cellular mechanisms underlying Aß-stimulated ROS production. Here, we identified ion channels involved in Aß-induced microglial ROS production and in Aß-induced microglial priming. Acute stimulation of microglial cells with either fibrillar Aß(1-42) (fAß(1-42) ) or soluble Aß(1-42) (sAß(1-42) ) caused significant increases in microglial ROS production, which were abolished by inhibition of TRPV1 cation channels with 5-iodo-resiniferatoxin (I-RTX), but were unaffected by inhibition of K(+) channels with charybdotoxin (CTX). Furthermore, pretreatment with either fAß(1-42) or sAß(1-42) induced microglial priming, that is, increased ROS production upon secondary stimulation with the phorbol ester PMA. Microglial priming induced by fAß(1-42) or sAß(1-42) remained unaffected by TRPV1 channel inhibition with I-RTX. However, sAß(1-42) -induced priming was inhibited by CTX and margatoxin, but not by TRAM-34 or paxilline, indicating a role of Kv1.3 voltage-gated K(+) channels, but not of Ca(2+) -activated K(+) channels, in the priming process. In summary, our data suggest that in microglia Aß-induced ROS production and priming are differentially regulated by ion channels, and that TRPV1 cation channels and Kv1.3 K(+) channels may provide potential therapeutic targets to reduce microglia-induced oxidative stress in Alzheimer's disease.

Sodium dependence of lysophosphatidylcholine-induced caspase-1 activity and reactive oxygen species generation.

The proinflammatory cytokines interleukin (IL)-1ß and IL-18 play pivotal roles in neuroinflammatory diseases. Caspase-1-mediated proteolytic cleavage is required to convert the premature, biologically inactive cytokines to their biologically active forms capable of promoting tissue inflammation. Although caspases have been recognized as potential therapeutic targets in inflammatory diseases, mechanisms regulating caspase-1 activation are not fully understood. Here we demonstrate that the proinflammatory lipid lysophosphatidylcholine (LPC) initiates microglial caspase-1 activation in a Na(+)-dependent manner. LPC-induced caspase-1 activity was almost completely inhibited upon omission of extracellular Na(+), but was unaffected by inhibition of Na(+)/K(+)-ATPase with ouabain or by inhibition of Na(+)/H(+) antiport with amiloride. Inhibition of caspase-1-mediated IL-1ß processing by Na(+)-free medium led to reduced amounts of mature IL-1ß released from LPC-stimulated microglia. Furthermore, LPC-induced production of reactive oxygen species (ROS) was abolished by Na(+)-free medium, indicating Na(+) dependence of NADPH oxidase activity in LPC-stimulated microglia. Since ROS production was found to be crucial to caspase-1 activation in LPC-stimulated microglia, the Na(+) dependence of caspase-1 can be related to the Na(+) dependence of NADPH oxidase. In summary, it is suggested that in LPC-activated microglia, Na(+) influx is required for the production of NADPH oxidase-mediated ROS, which subsequently stimulate caspase-1 activity.

Importance of lipid rafts for lysophosphatidylcholine-induced caspase-1 activation and reactive oxygen species generation.

Lipid rafts play an important role in regulating cellular processes and functions. Here, we demonstrate that in microglia stimulated with the pro-inflammatory lipid lysophosphatidylcholine (LPC), caspase-1 activation and NADPH oxidase activity depend on intact lipid rafts. Disruption of lipid rafts with methyl-ß-cyclodextrin, fumonisin B1 or nystatin prevented LPC-stimulated caspase-1 activation and reactive oxygen species (ROS) production, whereas LPC-induced Na(+) influx remained unaffected. Since ROS regulate caspase-1 activity in LPC-stimulated microglia, the effects of lipid raft-disrupting agents on caspase-1 activation can be related to their inhibition of NADPH oxidase-mediated ROS production.

Stimulus-dependent requirement of ion channels for microglial NADPH oxidase-mediated production of reactive oxygen species.

Reactive oxygen species (ROS) produced by activated microglial cells play a pivotal role in the pathogenesis of neuro-degenerative and neuro-inflammatory diseases. Here we demonstrate that the pro-inflammatory lipid lysophosphatidylcholine (LPC) is capable of inducing microglial ROS production, which is mediated by the activity of NADPH oxidase. Inhibition of TRPV1 non-selective cation channels abolished ROS production in LPC-stimulated microglia, whereas inhibitors of K(+) channels, H(+) channels and Cl(-) channels had no significant effects. In contrast, activity of all four ion channel types was required for PMA-induced NADPH oxidase-mediated ROS generation, suggesting a differential, stimulus-dependent regulation of microglial ROS production by ion channel activity.

Importance of the non-selective cation channel TRPV1 for microglial reactive oxygen species generation.

Activated microglial cells generate reactive oxygen species (ROS), which have detrimental effects in neuroinflammatory and neurodegenerative diseases. In the present study, we have identified a novel mechanism involved in microglial NADPH oxidase-mediated ROS production. In PMA-stimulated microglia, ROS production was substantially reduced upon inhibition of the non-selective cation channel TRPV1 with La(3+), ruthenium red, capsazepine and 5-iodo-resinferatoxin. Furthermore, sustained membrane depolarization, a hallmark of NADPH oxidase activity in phagocytes, was found to induce non-selective cation/TRPV1 channel activity in microglia. Together, our data suggest that TRPV1 channels are involved in regulating NADPH oxidase-mediated ROS generation in microglia.

Lysophosphatidylcholine- and MCP-1-induced chemotaxis of monocytes requires potassium channel activity.

One of the earliest cellular responses in atherogenesis is the focal recruitment of circulating monocytes, while the most important atherogenic chemoattractants are monocyte chemoattractant protein-1 (MCP-1) and lysophosphatidylcholine (LPC). Invading monocytes transform into activated macrophages and foam cells, which stimulate inflammatory processes and promote atherosclerosis. In this study, we have searched for common mechanisms involved in MCP-1- and LPC-stimulated monocyte migration. We have found that migration of THP-1 monocytes stimulated with MCP-1 was reduced upon inhibition of G(i/o) proteins with pertussis toxin and upon inhibition of platelet activating factor receptors with BN52021, whereas LPC-stimulated monocyte chemotaxis remained unaffected by both inhibitors. Furthermore, Cl(-) channels were only required for MCP-1-induced chemotaxis. However, activity of voltage-gated K+ channels and of Ca2+-activated K+ channels was found to be involved in migration of monocytes stimulated with either MCP-1 or LPC. Inhibition of voltage-gated K+ channels with 4-aminopyridine or margatoxin partially inhibited MCP-1- and LPC-stimulated migration of monocytes. Blockade of Ca2+-activated K+ channels with TRAM-34 also partially reduced migration of MCP-1- and LPC-stimulated monocytes. Simultaneous inhibition of voltage-gated and Ca2+-activated K+ channels abolished MCP-1- and LPC-induced chemotaxis of monocytes. Thus, K+ channel inhibition may represent a novel powerful strategy to reduce monocyte infiltration and subsequent inflammation in atherosclerosis.

Non-selective cation channel activity is required for lysophosphatidylcholine-induced monocyte migration.

Lysophosphatidylcholine (LPC) is a major atherogenic lipid which stimulates the recruitment of monocytes to atherosclerotic lesions. The physiological mechanisms underlying LPC-induced monocyte migration are poorly understood. Here we demonstrate that LPC activates non-selective cation channels, which are significantly involved in LPC-induced chemotaxis of monocytes. External LPC elicited the activation of non-selective cation currents in THP-1 monocytes, which occurred in a G protein and phospholipase C-independent manner. LPC-activated currents were almost completely inhibited by Gd(3+), La(3+), and TRAM-34. Furthermore, currents were partially reduced by either 2-aminoethoxydiphenyl borate (2-APB) or ruthenium red, while combined application of 2-APB and ruthenium red abolished LPC-activated currents. The 2-APB-sensitive current component was potentiated by flufenamic acid and Ca(2+)-free extracellular solution, while the ruthenium red-sensitive current component was abolished by capsazepine. This pharmacological profile suggests that LPC simultaneously activates TRPC6 and TRPV1 channels in monocytes. Furthermore, in the presence of Gd(3+), La(3+), TRAM-34, 2-APB, ruthenium red or capsazepine, LPC-induced chemotaxis of monocytes was substantially inhibited, indicating that activation of both channel types is required for optimal migration of LPC-stimulated monocytes. Thus, ion channel inhibition may represent a powerful strategy to attenuate the progression of atherosclerosis by reducing monocyte infiltration.