Activation of native TRPC1/C5/C6 channels by endothelin-1 is mediated by both PIP3 and PIP2 in rabbit coronary artery myocytes

We investigate activation mechanisms of native TRPC1/C5/C6 channels (termed TRPC1 channels) by stimulation of endothelin-1 (ET-1) receptor subtypes in freshly dispersed rabbit coronary artery myocytes using single channel recording and immunoprecipitation techniques. ET-1 evoked non-selective cation channel currents with a unitary conductance of 2.6 pS which were not inhibited by either ET(A) or ET(B) receptor antagonists, respectively BQ-123 and BQ788, when administered separately. However, in the presence of both antagonists, ET-1-evoked channel activity was abolished indicating that both ET(A) and ET(B) receptor stimulation activate this conductance. Stimulation of both ET(A) and ET(B) receptors evoked channel activity which was inhibited by the protein kinase C (PKC) inhibitor chelerythrine and by anti-TRPC1 antibodies indicating that activation of both receptor subtypes causes TRPC1 channel activation by a PKC-dependent mechanism. ET(A) receptor-mediated TRPC1 channel activity was selectively inhibited by phosphoinositol-3-kinase (PI-3-kinase) inhibitors wortmannin (50 nm) and PI-828 and by antibodies raised against phosphoinositol-3,4,5-trisphosphate (PIP(3)), the product of PI-3-kinase-mediated phosphorylation of phosphatidylinositol 4,5-bisphosphate (PIP(2)). Moreover, exogenous application of diC8-PIP(3) stimulated PKC-dependent TRPC1 channel activity. These results indicate that stimulation of ET(A) receptors evokes PKC-dependent TRPC1 channel activity through activation of PI-3-kinase and generation of PIP(3). In contrast, ET(B) receptor-mediated TRPC1 channel activity was inhibited by the PI-phospholipase C (PI-PLC) inhibitor U73122. 1-Oleoyl-2-acetyl-sn-glycerol (OAG), an analogue of diacylglycerol (DAG), which is a product of PI-PLC, also activated PKC-dependent TRPC1 channel activity. OAG-induced TRPC1 channel activity was inhibited by anti-phosphoinositol-4,5-bisphosphate (PIP(2)) antibodies and high concentrations of wortmannin (20 μm) which depleted tissue PIP(2) levels. In addition exogenous application of diC8-PIP(2) activated PKC-dependent TRPC1 channel activity. These data indicate that stimulation of ET(B) receptors evokes PKC-dependent TRPC1 activity through PI-PLC-mediated generation of DAG and requires a permissive role of PIP(2). In conclusion, we provide the first evidence that stimulation of ET(A) and ET(B) receptors activate native PKC-dependent TRPC1 channels through two distinct phospholipids pathways involving a novel action of PIP(3), in addition to PIP(2), in rabbit coronary artery myocytes

Var-CNN: A Data-Efficient Website Fingerprinting Attack Based on Deep Learning

In recent years, there have been several works that use website fingerprinting techniques to enable a local adversary to determine which website a Tor user visits. While the current state-of-the-art attack, which uses deep learning, outperforms prior art with medium to large amounts of data, it attains marginal to no accuracy improvements when both use small amounts of training data. In this work, we propose Var-CNN, a website fingerprinting attack that leverages deep learning techniques along with novel insights specific to packet sequence classification. In open-world settings with large amounts of data, Var-CNN attains over $1\%$ higher true positive rate (TPR) than state-of-the-art attacks while achieving $4\times$ lower false positive rate (FPR). Var-CNN's improvements are especially notable in low-data scenarios, where it reduces the FPR of prior art by $3.12\%$ while increasing the TPR by $13\%$. Overall, insights used to develop Var-CNN can be applied to future deep learning based attacks, and substantially reduce the amount of training data needed to perform a successful website fingerprinting attack. This shortens the time needed for data collection and lowers the likelihood of having data staleness issues.Comment: Original paper split into "Var-CNN: A Data-Efficient Website Fingerprinting Attack Based on Deep Learning" (PETS 2019) and "DynaFlow: An Efficient Website Fingerprinting Defense Based on Dynamically-Adjusting Flows" (WPES 2018

Part 2. Power Spectral Analysis

Automatic (computer) correlation of geophysical logs is complicated by stratigraphic thickening (or stretch) from one area to another. Previous algorithms compute the stretch with repeated crosscorrelations of the original logs. Program SPECOR presented in this report uses crosscorrelation of the power spectra of the logs to identify the stretch factor between logs in one simplified operation. Computations are performed in the frequency domain with the scequency intervals transformed to a logarithmic scale. Interpolation is required to obtain equally spaced power spectra. Given the stretch, displacement or lag between wells is computed rapidly by correlation processes, without needing to rely on iterative procedures

A Mouse Amidase Specific for N-terminal Asparagine: the gene, the enzyme, and their function in the N-end rule pathway

The N-end rule relates the in vivo half-life of a protein to the identity of its N-terminal residue. In both fungi and mammals, the tertiary destabilizing N-terminal residues asparagine and glutamine function through their conversion, by enzymatic deamidation, into the secondary destabilizing residues aspartate and glutamate, whose destabilizing activity requires their enzymatic conjugation to arginine, one of the primary destabilizing residues. We report the isolation and analysis of a mouse cDNA and the corresponding gene (termed Ntan1) that encode a 310-residue amidohydrolase (termed NtN-amidase) specific for N-terminal asparagine. The ~17-kilobase pair Ntan1 gene is located in the proximal region of mouse chromosome 16 and contains 10 exons ranging from 54 to 177 base pairs in length. The ~1.4-kilobase pair Ntan1 mRNA is expressed in all of the tested mouse tissues and cell lines and is down-regulated upon the conversion of myoblasts into myotubes. The Ntan1 promoter is located ~500 base pairs upstream of the Ntan1 start codon. The deduced amino acid sequence of mouse NtN-amidase is 88% identical to the sequence of its porcine counterpart, but bears no significant similarity to the sequence of the NTA1-encoded N-terminal amidohydrolase of the yeast Saccharomyces cerevisiae, which can deamidate either N-terminal asparagine or glutamine. The expression of mouse NtN-amidase in S. cerevisiae nta1Delta was used to verify that NtN-amidase retains its asparagine selectivity in vivo and can implement the asparagine-specific subset of the N-end rule. Further dissection of mouse Ntan1, including its null phenotype analysis, should illuminate the functions of the N-end rule, most of which are still unknown

Inhibition of native TRPC6 channel activity by phosphatidylinositol 4,5-bisphosphate in mesenteric artery myocytes

The present work investigates the effect of phosphatidylinositol-4,5-bisphosphate (PIP2) on native TRPC6 channel activity in freshly dispersed rabbit mesenteric artery myocytes using patch clamp recording and co-immunoprecipitation methods. Inclusion of 100 μm diC8-PIP2 in the patch pipette and bathing solutions, respectively, inhibited angiotensin II (Ang II)-evoked whole-cell cation currents and TRPC6 channel activity by over 90%. In inside-out patches diC8-PIP2 also inhibited TRPC6 activity induced by the diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) with an IC50 of 7.6 μm. Anti-PIP2 antibodies potentiated Ang II- and OAG-evoked TRPC6 activity by about 2-fold. Depleters of tissue PIP2 wortmannin and LY294002 stimulated TRPC6 activity, as did the polycation PIP2 scavenger poly-l-lysine. Wortmannin reduced Ang II-evoked TRPC6 activity by over 75% but increased OAG-induced TRPC6 activity by over 50-fold. Co-immunoprecipitation studies demonstrated association between PIP2 and TRPC6 proteins in tissue lysates. Pre-treatment with Ang II, OAG and wortmannin reduced TRPC6 association with PIP2. These results provide for the first time compelling evidence that constitutively produced PIP2 exerts a powerful inhibitory action on native TRPC6 channels

Atelectasis Induced by Thoracotomy Causes Lung Injury during Mechanical Ventilation in Endotoxemic Rats

Atelectasis can impair arterial oxygenation and decrease lung compliance. However, the effects of atelectasis on endotoxemic lungs during ventilation have not been well studied. We hypothesized that ventilation at low volumes below functional residual capacity (FRC) would accentuate lung injury in lipopolysaccharide (LPS)-pretreated rats. LPS-pretreated rats were ventilated with room air at 85 breaths/min for 2 hr at a tidal volume of 10 mL/kg with or without thoracotomy. Positive end-expiratory pressure (PEEP) was applied to restore FRC in the thoracotomy group. While LPS or thoracotomy alone did not cause significant injury, the combination of endotoxemia and thoracotomy caused significant hypoxemia and hypercapnia. The injury was observed along with a marked accumulation of inflammatory cells in the interstitium of the lungs, predominantly comprising neutrophils and mononuclear cells. Immunohistochemistry showed increased inducible nitric oxide synthase (iNOS) expression in mononuclear cells accumulated in the interstitium in the injury group. Pretreatment with PEEP or an iNOS inhibitor (1400 W) attenuated hypoxemia, hypercapnia, and the accumulation of inflammatory cells in the lung. In conclusion, the data suggest that atelectasis induced by thoracotomy causes lung injury during mechanical ventilation in endotoxemic rats through iNOS expression

Beaver: A Decentralized Anonymous Marketplace with Secure Reputation

Amid growing concerns of government surveillance and corporate data sharing, web users increasingly demand tools for preserving their privacy without placing trust in a third party. Unfortunately, existing centralized reputation systems need to be trusted for either privacy, correctness, or both. Existing decentralized approaches, on the other hand, are either vulnerable to Sybil attacks, present inconsistent views of the network, or leak critical information about the actions of their users. In this paper, we present Beaver, a decentralized anonymous marketplace that is resistant against Sybil attacks on vendor reputation, while preserving user anonymity. Beaver allows its participants to enjoy open enrollment, and provides every user with the same global view of the reputation of other users through public ledger based consensus. Various cryptographic primitives allow Beaver to offer high levels of usability and practicality, along with strong anonymity guarantees. Operations such as creating a listing, purchasing an item, and leaving feedback take just milliseconds to compute and require generating just a few kilobytes of state while often constructing convenient anonymity sets of hundreds of transactions