K(+) regulates Ca(2+) to drive inflammasome signaling: dynamic visualization of ion flux in live cells

P2X₇ purinergic receptor engagement with extracellular ATP induces transmembrane potassium and calcium flux resulting in assembly of the NLRP3 inflammasome in LPS-primed macrophages. The role of potassium and calcium in inflammasome regulation is not well understood, largely due to limitations in existing methods for interrogating potassium in real time. The use of KS6, a novel sensor for selective and sensitive dynamic visualization of intracellular potassium flux in live cells, multiplexed with the intracellular calcium sensor Fluo-4, revealed a coordinated relationship between potassium and calcium. Interestingly, the mitochondrial potassium pool was mobilized in a P2X₇ signaling, and ATP dose-dependent manner, suggesting a role for mitochondrial sensing of cytosolic ion perturbation. Through treatment with extracellular potassium we found that potassium efflux was necessary to permit sustained calcium entry, but not transient calcium flux from intracellular stores. Further, intracellular calcium chelation with BAPTA-AM indicated that P2X₇-induced potassium depletion was independent of calcium mobilization. This evidence suggests that both potassium efflux and calcium influx are necessary for mitochondrial reactive oxygen generation upstream of NLRP3 inflammasome assembly and pyroptotic cell death. We propose a model wherein potassium efflux is necessary for calcium influx, resulting in mitochondrial reactive oxygen generation to trigger the NLRP3 inflammasome.

Diagnostic performance of magnetic resonance imaging for acute pulmonary embolism: a systematic review and meta-analysis

BACKGROUND

With ongoing technical developments, magnetic resonance imaging (MRI) has notably evolved for the assessment of the pulmonary vasculature. However, uncertainty persists about the performance of MRI for the diagnosis of acute pulmonary embolism (APE).

OBJECTIVES

To clarify the comprehensive role of MRI in diagnosing APE.

METHODS

Studies were identified through a search of Pubmed and Ovid databases, and the QUADAS-2 tool was applied for quality assessment of the included studies.

RESULTS

Fifteen studies based on patients and nine based on vessels were retrieved. The patient-based analysis yielded an overall sensitivity of 0.75 (95% confidence interval, 0.70-0.79) and 0.84 (0.80-0.87) for all patients and patients with technically adequate images, respectively, with an overall specificity of 0.80 (0.77-0.83) and 0.97 (0.96-0.98) and a pooled diagnostic odds ratio (DOR) of 51.07 (18.36-142.05) and 155.22 (86.83-277.47). On average, MRI was technically inadequate in 18.89% of patients (range, 2.10%-27.70%). A direct comparison of different MRI modalities showed that the combined MRI test had the highest pooled DOR and the lowest proportion of inconclusive images. Of note, heterogeneity and moderate quality were observed. On a vessel basis, the MRI had high sensitivity and specificity in larger-order vessels, but a significantly lower sensitivity of 0.55 (0.50-0.60) for subsegmental APE.

CONCLUSIONS

On a patient-based level, MRI yields high diagnostic accuracy for the detection of APE, especially in technically adequate images, and the inconclusive MRI examinations mainly result from motion artifact and poor arterial opacification. The combined MRI test appears to be a more promising diagnostic tool with greater power of discrimination than single techniques. From a vessel-based perspective, MRI exhibits a high diagnostic capability with proximal arteries, but lacks sensitivity for peripheral embolism.

Interaction between DNA/histone methyltransferases and their inhibitors

Epigenetic research has recently become one of the hotspots in the field of bioscience and drug design. DNA methylation and histone methylation serve a critical function in influencing gene expression and genome function. The inhibition of DNA and histone methyltransferases (DNMTs and HMTs) is a promising approach for the therapeutic treatment of numerous diseases, including cancer. This work reviews the recent achievements in methyltransferase crystallographic structure resolution and bioactive inhibitor screening. We discuss the features of DNA and HMT structures, as well as the mechanism and structure-function relationship of transferase inhibitors, to elucidate how methyltransferase and inhibitor interactions occur both internally and externally. This study briefly reviews the biological function, as well as the inhibitor discovery and development, of DNA/histone methyltransferases.

Kinetic and multidimensional profiling of accelerated degradation of oil sludge by biostimulation

Biostimulation, which employs nutrients to enhance the proliferation of indigenous microorganisms and therefore the degradation of contaminants, is an effective tool for treatment of oil-contaminated soil. However, the evolution of microbial ecology, which responds directly to stimulation procedures and intrinsically determines the degradation of oil contaminants, has rarely been explored, particularly in the context of biostimulation. In this study, the effects of biostimulation procedures including the regulation of the C : N : P ratio, as well as application of surfactants and electron acceptors in the degradation of crude oil contaminants and the evolution of the microbial community were examined simultaneously to provide ecological insights into the biostimulation. The real-time PCR showed that biostimulation promoted the proliferation of bacteria, with Gammaproteobacteria showing the greatest increase. However, the proliferation of fungi was inhibited by the accumulation of the degradation products. The degradation of polar compounds of crude oil contaminants was characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (negative-ion ESI FT-ICR MS), showing a biased increase in the relative abundance of naphthenic acids. Principal component analysis (PCA) showed that different species in oil sludge have different degradation rates during biostimulation. The addition of fertilizers with surfactants and electron acceptors profoundly stimulated the indigenous microorganisms with N1, O1 and O2 species as substrates while those with O3 and O4 species were little affected. An enriched abundance of alkB genes was observed during the degradation of saturated hydrocarbons. Monitoring the kinetics of the microbial community, functional genes and degradation offers a comprehensive view for the understanding and optimization of the biostimulation process.

Intraspecific and interspecific attraction of three Tomicus beetle species during the shoot-feeding phase

The shoot beetles Tomicus minor, Tomicus yunnanensis, and Tomicus brevipilosus have been decimating Pinus yunnanensis trees for more than 30 years in Southwestern China. To understand the chemical ecological relationship between pines and Tomicus, and among the three beetle species, we compared the attraction of these beetles to damaged shoots, extracts from damaged shoots, and volatiles from damaged shoots collected by the dynamic headspace sampling method. Experiments were performed using a modified open-arena olfactometer. The male T. minor and both sexes of T. brevipilosus were more strongly attracted to damaged shoots than to undamaged shoots and they showed attraction to shoots damaged by the same species. Female T. minor and both sexes of T. yunnanensis were attracted to shoots damaged by female T. brevipilosus. The three beetle species were attracted to shoot extracts and dynamic headspace volatiles from shoots damaged by the same species and sex. Female T. minor and male T. yunnanensis were also attracted to dynamic headspace volatiles from shoots damaged by both sexes of T. brevipilosus. The results suggested that specific semiochemicals that are induced or produced by T. brevipilosus also attract T. minor and T. yunnanensis. The semiochemicals in damaged shoots affect the attraction of the three beetle species and play an important chemical communication role in weakening the host trees during the beetles' shoot-feeding phase.

Evaluation of clinical measurements and development of new diagnostic criteria for Takayasu arteritis in a Chinese population

OBJECTIVES

Takayasu arteritis (TA) is a chronic granulomatous large-vessel vasculitis. When diagnosing TA, the criteria designed by the American College of Rheumatology (ACR) are used commonly but they were just classification criteria. There is an urgent need for a new set of diagnostic criteria.

METHODS

One hundred and thirty-one TA patients and 132 control patients with other types of vascular disease were enrolled and both groups were distributed into a "training set" and a "validation set". All general information as well as clinical, laboratory and imaging data were collected. After comparing all the medical records of two groups in the training set, logistic regression and clinical judgment were used to form the new criteria for TA. The new criteria were tested by the validation set.

RESULTS

New TA diagnostic criteria within total score 26 include age (<40 years), female, chest pain/chest distress, amaurosis, vascular bruits, a decreased/absent pulse, involvement of the aortic arch or its major branches, and involvement of the abdominal aorta or its branches. Patients with a score ≥ 8 were diagnosed as TA. The sensitivity and specificity of our new criteria were 91.92% and 93.94%, respectively, higher than those of the ACR criteria (75.76%, 85.86%) and the Ishikawa criteria (56.57%, 94.95%). The areas under the ROC curves of the new criteria and ACR criteria were 0.981 and 0.868, respectively (p<0.001). Sensitivity and specificity tested in the validation set were 90.63% and 96.97%, respectively.

CONCLUSIONS

The new diagnostic criteria exhibited high sensitivity and specificity and have demonstrated to be feasible in the diagnosis of TA.

A molecular theory for optimal blue energy extraction by electrical double layer expansion

Tuning the electrode pore size (H) and the charging potential (Ψ₀) may lead to significant increases of the thermodynamic efficiency and the work output for capacitive double layer expansion processes.

A multi-scale molecular dynamics simulation of PMAL facilitated delivery of siRNA

PMAL as a novel carrier for the delivery of siRNA into lipid bilayer membranes.

How ABA block polymers activate cytochrome c in toluene: molecular dynamics simulation and experimental observation

The temperature responsiveness of ABA-polymer-conjugated Cyt c and its improved dispersion properties at high temperature have been investigated through both simulations and experiments.

Use of an intra-aortic balloon pump with chronic renal cardiac surgery

OBJECTIVE

To investigate the protective effect of an intra-aortic balloon pump (IABP) on renal function during open-heart surgery in patients with chronic renal insufficiency.

MATERIALS AND METHODS

Seventeen patients with moderate renal insufficiency who underwent cardiac pulmonary bypass surgery were randomly assigned to receive either IABP or usual care (control group). In the IABP group, the IABP was inserted immediately after anesthesia, and built-in counterpulsation was continued during aortic blockade. The IABP was gradually removed when postoperative hemodynamics and renal function was recovered. Clinical parameters related to renal function, including urine output and serum creatinine levels, were recorded perioperatively.

RESULTS

Urine volume during surgery, postoperative usage of diuretics, and mechanical ventilation time were better in the IABP group than in the control group. Serum creatinine increased after surgery in both groups, but the increase was significantly smaller in the IABP group.

CONCLUSIONS

Preoperative use of IABP in patients with moderate renal insufficiency undergoing cardiac surgery can help protect renal function and may improve prognosis.

Molecular Theory for Electrokinetic Transport in pH-Regulated Nanochannels

Ion transport through nanochannels depends on various external driving forces as well as the structural and hydrodynamic inhomogeneity of the confined fluid inside of the pore. Conventional models of electrokinetic transport neglect the discrete nature of ionic species and electrostatic correlations important at the boundary and often lead to inconsistent predictions of the surface potential and the surface charge density. Here, we demonstrate that the electrokinetic phenomena can be successfully described by the classical density functional theory in conjunction with the Navier-Stokes equation for the fluid flow. The new theoretical procedure predicts ion conductivity in various pH-regulated nanochannels under different driving forces, in excellent agreement with experimental data.

Mechanism of motilin-mediated inhibition on voltage-dependent potassium currents in hippocampal neurons

OBJECTIVE

The effects of motilin on voltage-dependent K+ currents in hippocampal neurons with the addition of L-arginine (L-AA), D-arginine (D-AA) and N-nitro-L-arginine methyl ester (L-NAME) were investigated in this study.

METHODS

Mice (1-3 days old) were randomly assigned to different groups according to the addition of motilin, L-AA, D-AA, and L-NAME. The K+ current signals were detected by the whole-cell patch-clamp technique.

RESULTS

Compared with the control group, the transient outward voltage-dependent K+ current was significantly inhibited by motilin added with L-AA. In contrast, the addition of motilin and L-NAME significantly increased the K+ current, while no significant change was detected by the addition of motilin accompanied with D-AA.

CONCLUSION

The inhibiting effects of motilin on the voltage-dependent K+ current in hippocampal neurons indicate that motilin acts as a regulatory factor for the nitric oxide pathway.

Nuclear magnetic resonance spectroscopy with single spin sensitivity

Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen-vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four (29)Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds.

A critical review of traditional Chinese medicine use amongst women with menopausal symptoms

OBJECTIVES

To provide the first critical review of traditional Chinese medicine (TCM) use amongst symptomatic menopausal women, drawing upon work examining the perspectives of both TCM users and TCM practitioners.

METHODS

A search was conducted in three English-language databases (MEDLINE, CINAHL and AMED) and three Chinese-language databases (CNKI, VIP and CBM Disc) for 2002-2013 international peer-reviewed articles reporting empirical findings of TCM use in menopause.

RESULTS

A total of 25 journal articles reporting 22 studies were identified as meeting the review inclusion criteria. Chinese herbal medicine appears to be the most common therapy amongst symptomatic menopausal women, and vasomotor symptoms and emotional changes are the most frequent symptoms for which TCM is sought. However, evidence regarding the prevalence of TCM use and users' profile in menopause is limited. Existing studies are of varied methodological quality, often reporting low response rate, extensive recall bias and a lack of syndrome differentiation.

CONCLUSIONS

This review provides insights for practitioners and health policy-makers regarding TCM care to symptomatic menopausal women. More nationally representative studies are required to rigorously examine TCM use for the management of menopausal symptoms. Syndrome differentiation of menopausal women is an area which also warrants further attention.

The overexpression of a maize mitogen-activated protein kinase gene (ZmMPK5) confers salt stress tolerance and induces defence responses in tobacco

As sessile organisms, plants are exposed to potential dangers, including multiple biotic and abiotic stresses. The mitogen-activated protein kinase (MAPK) is a universal signalling pathways involved in these processes. A previous study showed that maize ZmMPK5 is induced by various stimuli at transcriptional and post-translational levels. In this study, ZmMPK5 was overexpressed in tobacco to further analyse its biological functions. Under salt and oxidative stresses, ZmMPK5-overexpressing lines displayed less severe damage and stronger growth phenotypes corresponding to a series of physiological changes. In addition, the transgenic lines accumulated less reactive oxygen species (ROS) and had higher levels of antioxidant enzyme activity and metabolites than wild-type (WT) plants following NaCl treatment. Quantitative RT-PCR revealed that the expression of ROS-related and stress-responsive genes was higher in transgenic plants than in WT plants. Furthermore, transgenic lines exhibited enhanced resistance to viral pathogens, and expressed constitutively higher transcript levels of pathogenesis-related genes, such as PR1a, PR4, PR5 and EREBP. Taken together, these results demonstrated that ZmMPK5 is involved in salt stress, oxidative stress and pathogen defence signalling pathways, and its function may be at least partly devoted to efficiently eliminating ROS accumulation under salt stress.

Surface tension effects on the phase transition of a DPPC bilayer with and without protein: a molecular dynamics simulation

A coarse-grained molecular dynamics simulation was applied to illustrate the phase transition behavior of the pure DPPC bilayer and aquaporin-embedded DPPC bilayer under different surface tensions.

Multiscale simulation of surfactant–aquaporin complex formation and water permeability

Molecular dynamics simulation reveals distinctive roles of electrostatic and hydrophobic interactions in surfactant (SDS)–protein (AqpZ) complex formation and functionality.

Electrokinetic desalination using honeycomb carbon nanotubes (HC-CNTs): a conceptual study by molecular simulation

Electrokinetic desalination using honeycomb carbon nanotubes (CNTs) with high efficiency.

BRCC2 inhibits breast cancer cell growth and metastasis in vitro and in vivo via downregulating AKT pathway

In our previous study, we demonstrated that the BRCC2 (breast cancer cell 2) gene is a proapoptotic molecule that interacts with Bcl-X_L. BRCC2 downregulation is associated with poor disease-free and overall survival in breast cancer. In this study, we aimed to investigate the role of BRCC2 in tumor suppression in breast cancer. In clinical breast cancer samples, we found that BRCC2 expression was significantly downregulated in cancer lesions compared with paired normal breast tissues. By silencing or overexpressing BRCC2 in breast cancer cells, we found that BRCC2 could inhibit cell growth and metastasis in vitro. An in vivo assay showed that BRCC2 not only dramatically inhibited breast cancer cell xenograft formation and growth but also inhibited breast cancer cell metastasis in a lung metastasis model. Moreover, we demonstrated that BRCC2 inhibited breast cancer metastasis via regulation of the Akt pathway. Thus, our study provided evidence that BRCC2 functions as a novel tumor suppressor in breast cancer and may be a potential therapeutic target for breast cancer management.

Nanoscale imaging of InN segregation and polymorphism in single vertically aligned InGaN/GaN multi quantum well nanorods by tip-enhanced Raman scattering

Vertically aligned GaN nanorod arrays with nonpolar InGaN/GaN multi quantum wells (MQW) were grown by MOVPE on c-plane GaN-on-sapphire templates. The chemical and structural properties of single nanorods are optically investigated with a spatial resolution beyond the diffraction limit using tip-enhanced Raman spectroscopy (TERS). This enables the local mapping of variations in the chemical composition, charge distribution, and strain in the MQW region of the nanorods. Nanoscale fluctuations of the In content in the InGaN layer of a few percent can be identified and visualized with a lateral resolution below 35 nm. We obtain evidence for the presence of indium clustering and the formation of cubic inclusions in the wurtzite matrix near the QW layers. These results are directly confirmed by high-resolution TEM images, revealing the presence of stacking faults and different polymorphs close to the surface near the MQW region. The combination of TERS and HRTEM demonstrates the potential of this nanoscale near-field imaging technique, establishing TERS as a very potent, comprehensive, and nondestructive tool for the characterization and optimization of technologically relevant semiconductor nanostructures.