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The loop source TEM method has been widely used in the detection of a mined out area in China. In the cases that the laying of traditional rectangle or square transmitting loop is limited due to the presence of obstacle on the path of the loop, the changing of the shape of the transmitting loop to bypass the obstacle is a labor saving solution. A numeric integration scheme is proposed to calculate the response and Jacobian of the segmented loop source from that of an electric dipole source. The comparison of forward response between the segmented loop and square loop shows the effect of loop geometry on the decay curves. In order to interpret the data from an irregular source loop, this paper presents an inversion scheme that incorporate the effect of loop geometry. The proposed inversion scheme is validated on the synthetic data, and then applied to the field data. The result reveals that the developed inversion scheme is capable of interpreting the segmented loop source TEM field data.

Background. Daclatasvir is an NS5A inhibitor approved for treatment of infection due to hepatitis C virus (HCV) genotypes (GTs) 1–4. To support daclatasvir use in HCV genotype 4 infection, we examined a diverse genotype 4–infected population for HCV genotype 4 subtype prevalence, NS5A polymorphisms at residues associated with daclatasvir resistance (positions 28, 30, 31, or 93), and their effects on daclatasvir activity in vitro and clinically. Methods. We performed phylogenetic analysis of genotype 4 NS5A sequences from 186 clinical trial patients and 43 sequences from the European HCV database, and susceptibility analyses of NS5A polymorphisms and patient-derived NS5A sequences by using genotype 4 NS5A hybrid genotype 2a replicons. Results. The clinical trial patients represented 14 genotype 4 subtypes; most prevalent were genotype 4a (55%) and genotype 4d (27%). Daclatasvir 50% effective concentrations for 10 patient-derived NS5A sequences representing diverse phylogenetic clusters were ≤0.080 nM. Most baseline sequences had ≥1 NS5A polymorphism at residues associated with daclatasvir resistance; however, only 3 patients (1.6%) had polymorphisms conferring ≥1000-fold daclatasvir resistance in vitro. Among 46 patients enrolled in daclatasvir trials, all 20 with baseline resistance polymorphisms achieved a sustained virologic response. Conclusions. Circulating genotype 4 subtypes are genetically diverse. Polymorphisms conferring high-level daclatasvir resistance in vitro are uncommon before therapy, and clinical data suggest that genotype 4 subtype and baseline polymorphisms have minimal impact on responses to daclatasvir-containing regimens.

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling pathway plays crucial roles in cell proliferation, angiogenesis, migration, and survival. Aberration in FGFRs correlates with several malignancies and disorders. FGFRs have proved to be attractive targets for therapeutic intervention in cancer, and it is of high interest to find FGFR inhibitors with novel scaffolds. In this study, a combinatorial three-dimensional quantitative structure-activity relationship (3D-QSAR) model was developed based on previously reported FGFR1 inhibitors with diverse structural skeletons. This model was evaluated for its prediction performance on a diverse test set containing 232 FGFR inhibitors, and it yielded a SD value of 0.75 pIC50 units from measured inhibition affinities and a Pearson’s correlation coefficient R2 of 0.53. This result suggests that the combinatorial 3D-QSAR model could be used to search for new FGFR1 hit structures and predict their potential activity. To further evaluate the performance of the model, a decoy set validation was used to measure the efficiency of the model by calculating EF (enrichment factor). Based on the combinatorial pharmacophore model, a virtual screening against SPECS database was performed. Nineteen novel active compounds were successfully identified, which provide new chemical starting points for further structural optimization of FGFR1 inhibitors.

The central-loop time-domain electromagnetic (TEM) method has been widely used in hydrogeological prospecting. Because this type of TEM configuration is relatively insensitive to lateral resistivity contrasts, the mathematical derivation of an apparent resistivity formula, valid for later recording times, is greatly simplified. However, no simple formula exists for an in-loop off-center TEM sounding. In this type of acquisition, the field response is recorded at several points surrounding the central location. In-loop TEM surveys are frequently employed to obtain high spatial resolution within engineering geophysical exploration. Although the apparent resistivity formula of a fixed-loop TEM system is also applicable for the non-central receiver points used in an in-loop TEM system, the apparent resistivity values need to be extracted using an iterative method that requires complicated integrations. Presently, no fast method exists that can give access to the apparent resistivity values in a direct manner. The main objective of this paper is to present a possible solution to this computational problem. A new solution is presented that takes as a starting point a circular transmitter loop where an analytical solution exists for non-central receiver points. This analytical solution is further approximated through the combined use of least-mean square (LSQR) determined polynomial coefficients and an equivalent circular loop to represent the rectangular loop. The new apparent resistivity formula, valid for in-loop TEM, has been tested on field data. A successful case study from central China is presented where an increased sensitivity to locate water-filled zones has been obtained.

Traditional TEM study mainly focuses on the generation and application of the TE field using a loop or grounded-wire source; but in recent decades, lots of efforts have been made for implementation of the TM field and even the integration of the TE field with the TM one into anomaly detection in the subsurface. However, no applicable principles have been proposed for selecting the optimal electromagnetic field for various subsurface targets. The transient electromagnetic (TEM) fields generated from grounded-wire source consist of the TE-mode response (current-carrying wire), the TE–TM mode response (grounding ends) and the combined TEM-mode response (current-carrying wire and grounding ends). This study performs a comparison of TE/TE–TM/TEM fields by generating them from grounded-wire source and testing their distribution characteristics, detection depth, and sensitivity to anomalies, using both synthetic 1D model and two field surveys in China. The comparisons demonstrate that, the detection depth of the TE–TM field is smaller than those of both the TE and combined TEM fields. Meanwhile, for electric field, the TE–TM response provides a better detection than the TEM one, but with an uneven distribution. Therefore, the TE–TM electric field requires well-designed arrangements of receiving positions when applied to real projects. For the magnetic field, the TEM response has the best detection capability compared to the TE and TE–TM ones, but is least sensitive to layer thickness and resistivity, especially for an embedded layer with low resistivity.

Background Daclatasvir (DCV) is an approved NS5A inhibitor with potent anti-HCV activity and broad genotype coverage. DCV resistance-associated variants (RAVs) have been described for patients infected with genotype (GT) 1, but increased GT4 prevalence in European countries as a result of immigration has boosted interest in this genotype. Objectives Establishment of NS5A variability in treatment-naive patients with HCV genotype 4 infection and a case study of the dynamics of resistance-associated variants in a virologic failure receiving pIFN/RBV + DCV, as assessed by ultra-deep sequencing. Study design Five treatment-naive GT4 patients (GT4a [n = 1], GT4d [n = 3], GT4o [n = 1]) were evaluated for inclusion in the COMMAND-4 study and treatment with pIFN/RBV ± DCV. Results Patient (Pt) 1 received pIFN/RBV; Pts2–4 received pIFN/RBV + DCV; Pt5 was a screening failure. Pt1 relapsed; Pt2 experienced breakthrough at Wk4; Pts3 and 4 achieved a sustained virologic response. No substitutions associated with DCV-resistance were detected at baseline. In terms of viremic time points for Pts1 and 2, the extent of NS5A diversity pre-treatment was not significantly related to viral load (r = −0568; p = 0.035). In Pt2, multiple substitutions associated with DCV-resistance were observed after breakthrough at NS5A amino acid positions 28, 31 and 93. These substitutions were frequently observed on the same haplotype (L28S + M31I = 55.52, 82.50, and 99.36% at Wk4, 8 and 9; L28S + M31I + Y93H = 11.77, 5.01 and Conclusions This is the first report to describe DCV-resistance in patients infected with GT4d, supporting a possible role for a recently described RAV (L28S), and presenting the dynamics of HCV quasispecies during therapy failure, with indications of changes of diversity and association of mutations.

The dipole hypothesis commonly used in the description of electromagnetic fields associated with TEM loop antennas or grounded wire source is not accurate enough in the near-source zones where the response is also of significant importance for clearly mapping subtle structures embedded in shallow settings with geologic complexities. In order to better understand these near-source errors, we investigate the scale of errors resulting from the direct-dipole and superposing-dipole approximation of the large loop or long grounded wire sources. The results demonstrate that both the direct-dipole approximation and the superposing-dipole approximation fail to give accurate results in the near-source zone. Not only the direct-dipole approximation but also superposing-dipole approximation will arouse some errors. Therefore, a ‘point-charge’ solution of the EM damped wave equation is proposed and derived to calculate the near source responses. Forward modeling and field data analysis demonstrate that the proposed method provides more accurate results in the near source areas and can be effectively used to calculate the TEM response in the near source region.

The transient electromagnetic method has been extensively used for the detection of mined-out area in China for the past few years. In the cases that the mined-out area is overlain by a conductive layer, the detection of the target layer is difficult with a traditional loop source TEM method. In order to detect the target layer in this condition, this paper presents a newly developed array TEM method, which uses a grounded wire source. The underground current density distribution and the responses of the grounded wire source TEM configuration are modeled to demonstrate that the target layer is detectable in this condition. The 1D OCCAM inversion routine is applied to the synthetic single station data and common middle point gather. The result reveals that the electric source TEM method is capable of recovering the resistive target layer beneath the conductive overburden. By contrast, the conductive target layer cannot be recovered unless the distance between the target layer and the conductive overburden is large. Compared with inversion result of the single station data, the inversion of common middle point gather can better recover the resistivity of the target layer. Finally, a case study illustrates that the array TEM method is successfully applied in recovering a water-filled mined-out area beneath a conductive overburden.

Conventional use of the controlled-source audio-frequency magneto-telluric (CSAMT) method is based on calculating the apparent or Cagniard resistivity from the amplitude ratio of the horizontal electric and magnetic field components. However, direct comparison between these two components shows that the electric field is more sensitive to the underground medium resistivity than its magnetic counterpart. Thus, use of the electric component only should provide adequate information about the electric properties of the subsurface. The measurements typically belong to the far-field zone, but show a non-dipolar characteristic because of the source. In this paper, we therefore propose a simplified CSAMT technique based on measuring the electric field component only. As part of this new formulation, a related theoretical model for the electric field component accounting for the non-dipolar nature of the transmitter antenna is introduced. This is accompanied with a new apparent resistivity definition, including a procedure to transform it into pseudo-phase data, thus removing the static shifts.The potential of this modified CSAMT method is demonstrated using a field case from the Shanxi province in China. Until recently, it has been thought that no coal deposits exist in this region. However, application of the single-component CSAMT technique as advocated for here, revealed a major coal deposit, which was verified later by drilling.

Biomechanics is a fundamental feature of a cell. The manner by which a mechanical feature could affect immune evasion of tumor cells remains an enigma. Here we show that although cytotoxic T lymphocytes (CTL) can effectively destroy stiff differentiated tumor cells, they fail to kill tumor-repopulating cells (TRC), whose softness effectively impedes the pore formation process through perforin released from CTLs. Mechanistically, perforin interacting with nonmuscle myosin heavy chain 9 transmits forces to fewer F-actins in soft TRCs, thus inducing a weak contractile force which is inadquate for pore formation by perforin. Stiffening soft TRCs confers perforin the drilling ability, leading to CTLs killing the TRCs, thus achieving a better tumor immunotherapeutic outcome. More importantly, overcoming the mechanical softness also enhances the killing of human TRCs by human CTLs. These findings provide mechanics-based immunotherapeutic strategies with potential clinical applications.

Water inrush from limestone coal beds is disastrous for coal mining. In general, it is very difficult to detect such water-enriched zones because of their relatively large burial depth. In this paper, we propose a novel transient electromagnetic method (TEM) configuration, short-offset transient electromagnetic method (SOTEM). Consistency of the results obtained from SOTEM measurements in the Shandong province, East China and drilling information indicate that the proposed TEM configuration not only improves the accuracy, but also enlarges the exploration depth for detecting water-enriched areas in coal mines ranging from 1,000 to 1,200 m depth. In this region, a majority of the deep coal beds are filled with water. The SOTEM technique was successfully employed in detecting the floor of a coal seam at a depth of about 1,500 m, as well as in identifying the location of the water-saturated area. These findings were later confirmed by subsequent drillings. Thus, our study indicates that SOTEM represents a convenient and effective technique for deep mineral and hydrogeological investigations due to its high sensitivity to conductive zones (water enriched areas) and vertical resolution.

Two novel small-molecule based theranostic agents encompassing the dual functions of detection and detoxification of mercury ion poisoning are developed.

Blood-brain barrier (BBB) is a highly complex physical barrier determining what substances are allowed to enter the brain. Support vector machine (SVM) is a kernel-based machine learning method that is widely used in QSAR study. For a successful SVM model, the kernel parameters for SVM and feature subset selection are the most important factors affecting prediction accuracy. In most studies, they are treated as two independent problems, but it has been proven that they could affect each other. We designed and implemented genetic algorithm (GA) to optimize kernel parameters and feature subset selection for SVM regression and applied it to the BBB penetration prediction. The results show that our GA/SVM model is more accurate than other currently available logBBmodels. Therefore, to optimize both SVM parameters and feature subset simultaneously with genetic algorithm is a better approach than other methods that treat the two problems separately. Analysis of our logBBmodel suggests that carboxylic acid group, polar surface area (PSA)/hydrogen-bonding ability, lipophilicity, and molecular charge play important role in BBB penetration. Among those properties relevant to BBB penetration, lipophilicity could enhance the BBB penetration while all the others are negatively correlated with BBB penetration.

Dipicolinate sensitized LaF 3 :Tb 3+ luminescent nanoparticles (DPA-NPs) have been successfully synthesized and characterized for their morphology, structural and optical properties. It was found that the prepared DPA-NPs were spherical with an average diameter of 10 nm and their surfaces were capped by citric acid radicals and DPA. And then the interaction between DPA-NPs and bovine serum albumin (BSA) was investigated by fluorescence quenching, UV–visible absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy under the simulative physiological conditions. The results showed that DPA-NPs had a strong ability to quench the intrinsic fluorescence of BSA by forming 1:1 ground-state complexes with a binding constant of about 10 4 L mol −1 . Moreover, the values of the calculated thermodynamic parameters suggested that hydrophobic forces and hydrogen bonds played major roles in stabilizing the complex. The displacement experiments indicated that the binding of DPA-NPs primarily occurred in sub-domain II A (site I) of BSA. The binding distance r was calculated to be 1.9 nm based on the theory of Forster׳s non-radiation energy transfer. Finally, the analysis of synchronous fluorescence, FT-IR, CD, and three-dimensional fluorescence spectra revealed that the microenvironment of amino acid residues and the conformation of BSA were changed after the addition of DPA-NPs.

Viral myocarditis is a widespread cardiac disease associated with inflammation and myocardial injury and is predominantly caused by coxsackievirus B3 (CVB3) infection in humans as well as in mice. CVB3-induced myocarditis shows sexually dimorphic sensitivity and is more prevalent in male mice. Our previous studies showed that natural killer (NK) cells played an indispensable role in CVB3-induced myocarditis, and female mice exhibited less pathological cardiac interferon gamma (IFN-γ)We investigated the influence of estrogen on cardiac IFN-γIn this study, we found that CVB3 stimulation could clearly induce IFN-γ expression by NK cells; however, this trend could be blunted by estrogen treatment. Consistently, ovariectomized female mice with decreased estrogen levels exhibited substantially increased enrichment of cardiac IFN-γOverall, this study might help us understand the mechanism of increased cardiac infiltration by IFN-γ

Background Daclatasvir (DCV; non-structural [NS]5A inhibitor) plus asunaprevir (ASV; NS3 inhibitor) plus beclabuvir (BCV; non-nucleoside NS5B inhibitor) is an approved regimen for hepatitis C virus (HCV) genotype (GT)-1 treatment in Japan. A comprehensive analysis of pre-treatment and treatment-emergent HCV resistance to this regimen ± ribavirin (RBV) was performed. Methods Data were pooled from five Phase 2/3 studies of DCV+ASV+BCV±RBV given for 12 weeks to GT-1a- or GT-1b-infected patients. The prevalence and impact of pre-treatment resistance-associated substitutions (RAS) in NS5A, NS3, and NS5B on sustained virological response (SVR) was assessed, as were emergent RAS and their post-treatment persistence. Results Baseline NS5A RAS (GT-1a: M28T, Q30H/L/R/S, L31M, Y93C/H; GT-1b: L31I/M, Y93C/H) were present in 5% (26/561) of GT-1a and 16% (85/537) of GT-1b sequences. SVR12 for GT-1b without RBV was 100% (82/82) with RAS and >99% (427/428) without RAS. For GT-1a, SVR12 without RAS was 97% (85/88) with RBV and 92% (410/447) without RBV; SVR12 with RAS was 100% (2/2) with RBV and 54% (13/24) without RBV. Baseline NS3 (at R155 or D168) and NS5B (at P495) RAS were rare (≤1%). Treatment-emergent NS5A RAS (mostly Q30E/H/K/R+Y93H/N) in GT-1a persisted 60 weeks post-treatment, while NS3 RAS (mostly R155K) and NS5B-P495L/S were no longer detected after 48 or 24 weeks, respectively. Conclusions DCV+ASV+BCV+RBV was highly efficacious in HCV GT-1 infection, including HCV GT-1b with NS5A RAS. The fitness of treatment-emergent RAS post-treatment was NS5A > NS3 > NS5B; NS3 and NS5B RAS were generally replaced by wild-type sequence within 48 weeks.

The adsorption behaviors of antimony (III) by copper-zinc alloy filter media (KDF) have been investigated by batch and column experiments. In the batch experiment, the effects of KDF dosage, contact time, and solution pH on Sb(III) removal were examined. Under the optimum conditions, the removal percentage is over 95.0 % at room temperature. In the column experiment, the effects of flow rate, bed height, and some foreign ions on Sb(III) removal were explored. It was found that the removal percentage is over 95.0 % under the optimum conditions, and HCO 3 and CO 2 had positive effects on the Sb(III) removal, while Ca 2+ , Na + , Cl , NO 3 and SO 2 had negligible effects. Additionally the KDF column for Sb(III) removal could be repeatedly used three times and its removal ability could be effectively recovered by a simple washing process with water. KDF exhibits a good performance for the Sb(III) removal from contaminated waters.

HIV-1 gp120 undergoes multiple conformational changes both before and after binding to the host CD4 receptor. BMS-626529 is an attachment inhibitor (AI) in clinical development (administered as prodrug BMS-663068) that binds to HIV-1 gp120. To investigate the mechanism of action of this new class of antiretroviral compounds, we constructed homology models of unliganded HIV-1 gp120 (UNLIG), a pre-CD4 binding-intermediate conformation (pCD4), a CD4 bound-intermediate conformation (bCD4), and a CD4/co-receptor-bound gp120 (LIG) from a series of partial structures. We also describe a simple pathway illustrating the transition between these four states. Guided by the positions of BMS-626529 resistance substitutions and structure–activity relationship data for the AI series, putative binding sites for BMS-626529 were identified, supported by biochemical and biophysical data. BMS-626529 was docked into the UNLIG model and molecular dynamics simulations were used to demonstrate the thermodynamic stability of the different gp120 UNLIG/BMS-626529 models. We propose that BMS-626529 binds to the UNLIG conformation of gp120 within the structurally conserved outer domain, under the antiparallel β20–β21 sheet, and adjacent to the CD4 binding loop. Through this binding mode, BMS-626529 can inhibit both CD4-induced and CD4-independent formation of the “open state” four-stranded gp120 bridging sheet, and the subsequent formation and exposure of the chemokine co-receptor binding site. This unique mechanism of action prevents the initial interaction of HIV-1 with the host CD4+ T cell, and subsequent HIV-1 binding and entry. Our findings clarify the novel mechanism of BMS-626529, supporting its ongoing clinical development. Proteins 2015; 83:331–350. © 2014 Wiley Periodicals, Inc.

In China, banded iron formation (BIF) ore deposits of Precambrian age are found at different burial depths. Current exploration programs are focused on deep-seated concealed iron ore deposits. As a consequence, integrated geological and geophysical data are crucial in increasing the success-rate for exploration success. We propose a strategy by which the underlying geological model for the study area is first investigated. The corresponding electromagnetic response can then be modeled, simulating a geophysical type of survey with appropriate uncertainties in the analysis. Based on such an integrated approach, the required precision of detecting deeply-buried deposits can be investigated. In addition, by employing supplementary geophysical data acquired over known BIF deposits, further insight is gained into real geological models. The viability of this approach is demonstrated herein through a case study, where a hidden BIF deposit located in Anhui Province was successfully detected. The actual field measurements were carried out employing the grounded-wire Short-Offset TEM (SOTEM) technique. The analysis of the survey data revealed two new anomalies, one of which was subsequently drilled. Drilling results later confirmed that this anomaly was associated with an ore body that is 60 m thick at a burial depth of 750 m.

The interaction between p -nitrophenol (PNP) with bovine serum albumin (BSA) was investigated by fluorescence quenching, UV–visible absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy under the simulative physiological conditions. It is found that PNP has a strong ability to quench the intrinsic fluorescence of BSA by forming a 1:1 ground-state complex with a binding constant of about 10 4 L mol −1 . The values of the calculated thermodynamic parameters suggest that hydrogen bonds and hydrophobic forces played major roles in stabilizing the complex. The displacement experiments indicate that the binding of PNP to BSA primarily occurred in the sub-domain IIA (site I) of BSA. The binding distance r was calculated to be 1.58 nm based on the theory of Forster׳s non-radiation energy transfer. The analysis of synchronous fluorescence, FT-IR, CD, and three-dimensional fluorescence spectra reveals that the microenvironment of amino acid residues and the conformation of BSA were changed after addition of PNP.

The conventional method for computing the apparent resistivity of any location within a rectangular loop is to use the associated vertical magnetic field or its time derivative by a well-developed central-loop equation. For central part of the loop, this definition of apparent resistivity is accurate, and the survey configuration is designated as modified central-loop TEM. However, when applied to the non-central part of the rectangular loop that often demonstrates uneven distribution of magnetic field the use of this equation runs the risk of producing computational errors. Instead of the uneven distribution of vertical magnetic field, ratio response of the orthogonal horizontal field components has a uniform field distribution. Furthermore, the decay curves of ratio response reveal the properties of translation and scaling. By examining the decay curves for different resistivity, a new definition of ratio apparent resistivity is proposed, which is applicable for any point in a loop with the uniform distribution of ratio response. With the proposed explicit function between ratio response and apparent resistivity, our new algorithm avoids the time-consuming iteration by solving a non-linear equation. Both theoretical modeling and real data example indicate the added value of our method on computational efficiency and accuracy.

Large loop transient electromagnetic (TEM) is a widely used surface exploration method for mapping electrically conductive bodies. However, when working in the mountainous areas of China, it is difficult to lay out large enough transmitter loops for conventional surveys. An option for this type of terrain is a newly designed TEM survey configuration that uses a small 3-m square loop in combination with a high current (1,000 A to 2,000 A) TEM transmitter to excite a powerful EM field for detecting targets at greater depths. The detection depth of the system is analyzed. After comparing the responses as well as the detection depths between this special system and standard large loop configurations, it is shown that: 1) a small loop system can result in a detection depth similar to that of a large loop system; and 2) a small loop system is superior to a large loop during shallow depth target detection as well as in mountainous areas. Sufficient signal intensity can be obtained by a small central loop configuration equipped with a high current transmitter and a large equivalent area receiver coil. A large trial survey was conducted on the surface of mountainous areas in the Shanxi Province of China. This TEM survey showed that the 3-m by 3-m transmitter loop system was an effective method for deep TEM sounding in mountainous areas.

Several magmatic Ni-Cu deposits associated with Permian-Triassic mafic-ultramafic intrusions have been discovered during the last three decades in the southern part of the Central Asian Orogenic Belt, the northeastern margin of Tarim, and the margin of the North China Craton. The accurate delineations of the large resistive rock masses are crucial for locating potential ore bodies when they are located beneath rock masse. The controlled-source electromagnetic method (CSEM) is an important tool for investigating resistivity contrast in earth subsurface. In this study, we present a comprehensive example of using frequency domain CSEM survey to delineate the resistive rock masses that are related to the forming of orebody. The horizontal electric field, which is more sensitive to resistive target than the other components, is used in our study. We first built a geophysical model of the survey area based on prior confirmed geophysical and geological information. Then, both forward and inverse modeling were performed in order to assess the detectability of the resistive ore-forming rock masses in the model. Finally, this study acquired field data in the Kalatongke Ni-Cu Deposit, which is located in the Kalatongke District of the southern section of the Central Asian Orogenic Belt, and is specifically part of China’s southern Altai Orogenic Belt. The resistive ore-forming rock masses were successfully identified during the survey process and further verified by the drilling results. It was observed that both the synthetic and field examples indicated that the adopted frequency domain CSEM method successfully measured the electrical fields, and could be utilized to explore deeply buried resistive targets in future prospecting activities.

Please cite this article as: Hassanein, T., Sims, K.D., Bennett, M., Gitlin, N., Lawitz, E., Nguyen, T., Webster, L., Younossi, Z., Schwartz, H., Thuluvath, P.J., Zhou, H., Rege, B., McPhee, F., Zhou, N., Wind-Rotolo, M., Chung, E., Griffies, A., Grasela, D.M., Gardiner, D.F., A Randomized Trial of Daclatasvir in Combination With Asunaprevir and Beclabuvir in Patients With Chronic Hepatitis C Virus Genotype 4 Infection, Journal of Hepatology (2015), doi: http://dx.doi.org/10.1016/j.jhep.2014.12.025

Here we report on the structure-based optimization of antibody-recruiting molecules targeting HIV gp120 (ARM-H). These studies have leveraged a combination of medicinal chemistry, biochemical and cellular assay analysis, and computation. Our findings have afforded an optimized analog of ARM-H, which is ~1000 fold more potent in gp120-binding and MT-2 antiviral assays than our previously reported derivative. Furthermore, computational analysis, taken together with experimental data, provides evidence that azaindole- and indole-based attachment inhibitors bind gp120 at an accessory hydrophobic pocket beneath the CD4-binding site and can also adopt multiple unique binding modes in interacting with gp120. These results are likely to prove highly enabling in the development of novel HIV attachment inhibitors, and more broadly, they suggest novel applications for ARMs as probes of conformationally flexible systems.

Based on a semi-cyanine fluorophore, a selective turn-on fluorescent probe semi-CyHP for the detection of nitroreductase (NTR) and hypoxia was designed and synthesized. It can be activated by NTR and to restore the pull–push electronic systems of semi-CyHF, which strongly fluoresces at 556 nm. Besides, the investigation of the hypoxic tumor cell imaging with semi-CyHP was significant with minimal endogenous interference.

Hepatitis C virus (HCV) NS3/NS4A serine protease is essential for viral replication, which is regarded as a promising drug target for developing direct-acting anti-HCV agents. In this study, sixteen novel compounds with cell-based HCV replicon activity ranging from 3.0 to 28.2 μM (IC50) were successfully identified by means of structure-based virtual screening. Compound 5 and compound 11, with an IC50 of 3.0 μM and 5.1 μM, respectively, are the two most potent molecules with low cytotoxicity.

An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge. In this study, a comparison between the electromagnetic fields of an infinitesimal point charge and a dipole has been presented. First, the time-domain potential function of a point source in a 3D conductive medium is derived. Then the electric and magnetic fields in a 3D homogeneous lossless space are derived via the relation between the potential and field. The field differences between the infinitesimal point charge and the dipole in the step-off time, far-source, and near-source zones are analyzed, and the accuracy of the solutions from these sources is investigated. It is also shown that the field of the infinitesimal point charge in the near-source zone is different from that of the dipole, whereas the far-source zone fields of these two sources are identical. The comparison of real and simulated data shows that the infinitesimal point charge represents the real source better than the dipole source.

In a sentinel cohort, hepatitis C virus (HCV) patients (primarily genotype [GT] 1a) were treated with daclatasvir (NS5A inhibitor) and asunaprevir (NS3 protease inhibitor). Preexistence, emergence, and persistence of resistance variants in patients who failed this treatment are described. HCV-infected null responders received daclatasvir (60 mg once daily) and asunaprevir (600 mg twice daily) alone (Group A, 11 patients) or with peginterferon alfa-2a and ribavirin (Group B, 10 patients) for 24 weeks. Resistance testing was performed on baseline samples and samples with HCV RNA ≥1,000 IU/mL at Week 1 through posttreatment Week 48. Resistance substitution susceptibility to inhibition by asunaprevir and daclatasvir was assessed using HCV replicon assays. In Group A, six GT1a patients experiencing viral breakthrough and one GT1a patient who relapsed had detectable NS5A (Q30E/R, L31V/M, Y93C/N) and NS3 (R155K, D168A/E/V/Y) resistance-associated variants at failure. Two of six viral breakthrough patients achieved SVR48 after treatment intensification with peginterferon alfa-2a and ribavirin. For 2/4 viral breakthrough patients not responding to treatment intensification, NS3 resistance variants changed (D168Y to D168T; R155K to V36M-R155K). At posttreatment Week 48, daclatasvir-resistant variants persisted while asunaprevir-resistant variants were generally replaced by wild-type sequences. The NS3 sequence remained unchanged in the one patient with NS3-R155K at baseline, relapse, and posttreatment Week 48. In Group B, no viral breakthrough was observed. Conclusion: The treatment failure of daclatasvir and asunaprevir in HCV GT1a patients was associated with both NS5A and NS3 resistance variants in prior null responders. NS5A resistance variants persisted while NS3 resistance variants generally decayed, suggesting a higher relative fitness of NS5A variants. (Hepatology 2013;53:902–911)

Background Hepatitis C virus (HCV) NS5A replication complex inhibitors (RCIs) have been shown to exhibit picomolar antiviral activity against genotype 1 (GT1) in vitro. This has translated into rapid and robust declines in HCV RNA in GT1 patients. Less is known about the susceptibility of other genotypes such as GT3 to inhibition by NS5A RCIs. Objectives To detect and phenotype naturally occurring HCVGT3 NS5A polymorphisms against two NS5A RCIs (daclatasvir [DCV] and GS-5885) currently in clinical development. Study design The NS5A region from 96 HCV GT3 treatment-naive patients spanning North America, Europe and Australia was determined. Results Phylogenetic analysis revealed a broad distribution with no significant geographic clustering. GT1 DCV resistance-associated variants (RAVs) were observed in GT3 subjects; variants (and their frequencies) included 28M/V (1%), 30A/K/S/T/V (10%), 31L/M (1%), E92A (1%) and Y93H (8.3%). A consensus sequence was used to generate a JFH1/3a-NS5A hybrid replicon and employed to assess susceptibility to NS5A RCIs. Against JFH1/3a-NS5A, DCV was more potent (EC50 = 0.52 nM) than GS-5885 (EC50 = 141 nM). DCV sensitivity was increased against JFH1/3a-NS5A-M28V (EC50 = 0.006 nM), A30V (EC50 = 0.012 nM), and E92A (EC50 = 0.004 nM) while the NS5A-A30K and -Y93H variants exhibited reduced sensitivity to DCV (EC50 values of 23 nM and 1120 nM, respectively) and to GS-5885 (EC50 values of 1770 nM and 4300 nM, respectively). Conclusions Substitutions conferring resistance to NS5A RCIs pre-existed in treatment-naive patients infected with HCV GT3. The effectiveness of these NS5A RCIs to exert efficacy in the clinic may depend on which inhibitor is used in combination with other antivirals.

Transient electromagnetic method can penetrate high-resistivity shielding layer and delineate underlying strata or structure. However, the shielding effects of low-resistivity layer on transient electromagnetic exploration are often ignored, especially for low-resistive overburden. It is of great importance to ensure exploration depth and improve detection precision by researching the relationship between low-resistive layer and electromagnetic field. In this paper, the propagation process of the subsurface and surface TEM field responses were simulated using finite-difference time-domain method (FDTD). And the characteristic response of low-resistivity overburden was studied using numerical modeling. The observation time with low-resistivity layer was estimated using observation time formula. It was shown that a low-resistivity layer will not only reduce the propagation speed of the field, but also weaken the response of low-resistivity target.

This paper presents a method for converting the full waveform electromagnetic response excited by the pseudo-random binary sequences (PRBS) into subsurface resistivity cross section, based on the recovery of the transient electromagnetic diffusion field. The impulse response of the earth is extracted from the full waveform data efficiently using the Wiener-Hopf equation. Then, the backward accumulation is used to obtain the step off response from the extracted earth impulse response. An OCCAM inversion routine, which incorporates the band limitation of the derived transient, is adopted to produce the geoelectric models. Finally, the method was applied to the experimental field data set, and the consistency between the recovered models and the geological condition verifies the validity of this method.

MicroRNAs (miRNAs) are believed to be resistant against radiotherapy in certain types of cancers. The aim of our study was to determine the clinical application of miRNAs in non-small cell lung cancer (NSCLC). Sixty NSCLC tissue samples and adjacent histologically normal tissues were obtained for miRNAs microarray analysis and validated by RT-qPCR. Correlation between miRNA expression level and clinicopathological features was evaluated. Our study examined the influence of changed miRNA expression on the damaged DNA and its associated radio sensitivity. Luciferase assay was performed to determine potential effects on the targeted gene. Our study identified fifteen altered miRNAs in which miR-328-3p was down regulated in NSCLC tumour tissue as compared to normal tissues. Down-expression of miR-328-3p was positively associated with an enhanced lymph node metastasis, advanced clinical stage and a shortened survival rate. miR-328-3p expression was decreased in A549 cells compared to other NSCLC cell lines. Up-regulation of miR-328-3p demonstrated a survival inhibition effect in A549 and restored NSCLC cells’ sensitivity to radio therapy. An increased miR-328-3p expression promoted irradiation-induced DNA damage in cells. γ-H2AX was identified as the direct target of miR-328-3p. Over-expressed miR-328-3p can improve the radiosensitvity of cells by altering the DNA damage/repair signalling pathways in NSCLC.

During the last decade, there have been many exploration achievements in the Tibetan Gangdese metallogenic belt. The Sharang area of the Tibetan region is covered by a low-temperature mineralized alterable clay that is considered to be a low-grade ore. Although small intervals of rich molybdenum (Mo) mineralization have been discovered, the ore deposit scale is limited and the condition of deep ore is still unknown. To explore these deeper targets, a modified large-loop TEM system was used in the Sharang area. The TEM receiver configuration is redesigned and the late-time resistivity equation of large-loop TEM has also been defined. During data processing, two regions with low resistivity anomalies were discovered. The interpreted results indicate that the main ore deposit is buried 200 m beneath the surface, and extends 600 m vertically. The total anomalous area associated with the ore deposit is estimated at 3.77 km2. The interpretation results are consistent with drilling data acquired after the geophysical survey. The results show that it is the first ultra-large porphyry molybdenum deposit that has been found in Tibet.

In some applications, especially for tunnel surveys and ancient tomb investigations, the scale of survey location is so small that it is impossible to lay a large enough transmitter loop for detection. A small-scale and high-power Transient Electromagnetic (TEM) transmitter configuration must be adapted to detect longer distance or greater depth. Redesigning the TEM surveying configuration may facilitate improving signal penetration and precision of TEM soundings. Based on physical simulation, a newly designed special-loop-source TEM survey configuration has been introduced, which employs four square apertures within a single large transmitter loop to excite stronger fields. The primary and secondary fields have been measured using both the new special-loop system and standard normal single loop TEM configuration for different receiver-transmitter separations and for different target depths. The response curves were compared, revealing that the primary field intensity and the secondary field response were improved by the special-loop transmitter system as compared to the standard system. The new special-loop configuration can be used for tunnel TEM prediction and other TEM investigations. A case study was conducted on tunnel forecasting in Hubei Province, China. This terra TEM survey showed that it is an effective and successful method for exploring and predicting challenging geological structures ahead of a tunnel wall during excavation.

The central-loop TEM technology has been widely used in mineral exploration, engineering and environmental investigations and assorted geologic studies. For easy and efficient working conditions, a square (or rectangular) loop is generally employed instead of a circular one. Any position within the inner one ninth of the central part of the loop is often designated as the central survey location (within which the field is assumed to be uniform), and referred to as a modified central-loop configuration. However, the deduced field parameters at such non-central positions when calculated by a central-loop formula result in decreased accuracy and possibly erroneous interpretation. A large-fixed loop offers the advantage of being able to determine the induced potential at any point inside or outside the loop. In this study we provide the formula for the large-fixed loop and receiver positions within the modified central-loop system and solve the problem. Specifically, we compute the electromagnetic response of any field point by using an electric dipole integration method. The full time-domain apparent resistivity values are then extracted by using an iterative method. Both theoretical modeling and real data examples indicate that such a configuration not only improves the accuracy for the TEM survey, but also enlarges the exploration depth, due to a large loop used in the deployment. The method is used for locating the water enriched areas in coal mines in Yangquan region of Shanxi province and in Bin County of Shaanxi province, China. The interpreted results are tested by later drilling, which confirmed our combined method to be a reliable and efficient method for deep sounding.

Azaindole derivatives derived from the screening lead 1-(4-benzoylpiperazin-1-yl)-2-(1H-indol-3-yl)ethane-1,2-dione (1) were prepared and characterized to assess their potential as inhibitors of HIV-1 attachment. Systematic replacement of each of the unfused carbon atoms in the phenyl ring of the indole moiety by a nitrogen atom provided four different azaindole derivatives that displayed a clear SAR for antiviral activity and all of which displayed marked improvements in pharmaceutical properties. Optimization of these azaindole leads resulted in the identification of two compounds that were advanced to clinical studies: (R)-1-(4-benzoyl-2-methylpiperazin-1-yl)-2-(4-methoxy-1H-pyrrolo[2,3-b]pyridin-3-yl)ethane-1,2-dione (BMS-377806, 3) and 1-(4-benzoylpiperazin-1-yl)-2-(4,7-dimethoxy-1H-pyrrolo[2,3-c]pyridin-3-yl)ethane-1,2-dione (BMS-488043, 4). In a preliminary clinical study, 4 administered as monotherapy for 8 days, reduced viremia in HIV-1-infected subjects, providing proof of concept for this mecha...

CSAMT always use MT to calculate the Cagniard resistivity which is the ratio of electric field component and magnetic field component. CSAMT field source is known and the electric field component and the magnetic field component have a certain relationship with the underground resistivity. Therefore the single-component date including magnetic field component or electric field component can be used to extract the apparent resistivity. In order to improve the influence of noise to data interpretation, the paper put forward that the single-component of CSAMT is used to calculate the apparent resistivity through analyzing the data quality of magnetic field component and electric field component. The generalized inverse matrix inversion method is used and the layer number equals to time channel. The method overcomes the problem that the layer number is low, and the fitting inversion of the apparent resistivity curve in the whole field is realized. The detection of the result of seeper mine-out area in Datong show that the single-component detection and interpretation method is effective. Keywords—CSAMT; inversion interpretation; single- component date I. INTRODUCTION Controlled Source Audio-frequency Magnetotellurics (CSAMT for short) has been applied in geological survey, metal minerals, geothermal, hydro-geology, environmental geology, coal geology and other exploration . The ratio of the electric field component and the magnetic field component is used to define the apparent resistivity of the CSAMT. Although the ratio of apparent resistivity may be offset by the same interference, it is likely that quality of the measured magnetic field and electric field are different and the interference effects are also different because the polarization direction of electromagnetic interference is different, the environment and geological conditions are different (such as the earth's electric field component can't be observed or the quality is not high). However, CSAMT emission current is known, and the single component electric field and magnetic field can be separated so that the interaction between the single component and the magnetic field is avoided. The single-component apparent resistivity of CSAMT is derived through uniform earth far zone. In order to get the apparent resistivity that has hierarchical capabilities and is whole region, iterative algorithm is widely used

In antenna theory, the dipole hypothesis is applicable and widely used for observing the far-field radiation. However, when applied to near-field quasi-static radiation observation in geophysical surveying, the transceiver distance is often small, and thereby the source should not be treated as a dipole to avoid misfit between the observation and the modeling based on the dipole theory. To overcome such limitation, this paper first presents a new method of estimating the field generated from a dipole by dividing it into a series of infinitesimal point charge and computing both the velocity field excited by uniform-motion charge and accelerated-velocity field from accelerated charge, so that not only the far-field radiation but also the near-field quasi-static radiation can be accurately estimated. The results are well verified by the traditional methods of radiation modeling from a dipole. Then this study investigates the associated physical mechanism by developing a new equation for computing the radiated field in time-domain based on the frequency-to-time transformation, from which the relationship between a motive charge and its corresponding field is investigated. It is concluded that the field generated from dipole is in nature the same as that generated from motive charge.

A combinatorial pharmacophore (CP) model for Multidrug and toxin extrusion 1 (MATE1/SLC47A1) inhibitors was developed based on a data set including 881 compounds. The CP model comprises four individual pharmacophore hypotheses, HHR1, DRR, HHR2 and AAAP, which can successfully identify the MATE1 inhibitors with an overall accuracy around 75%. The model emphasizes the importance of aromatic ring and hydrophobicity as two important structural determinants for MATE1 inhibition. Compared with the pharmacophore model of Organic Cation Transporter 2 (OCT2/ SLC22A2), a functional related transporter of MATE1, the hypotheses of AAAP and PRR5 are suggested to be responsible for their ligand selectivity, while HHR a common recognition pattern for their dual inhibition. A series of analysis including molecular sizes of inhibitors matching different hypotheses, matching of representative MATE1 inhibitors and molecular docking indicated that the small inhibitors matching HHR1 and DRR involve in competitive inhibition, while the relatively large inhibitors matching AAAP are responsible for the noncompetitive inhibition by locking the conformation changing of MATE1. In light of the results, a hypothetical model for inhibiting transporting mediated by MATE1 was proposed.

Introduction Oral daclatasvir (DCV; pangenotypic NS5A inhibitor) plus asunaprevir (ASV; NS3 protease inhibitor) is approved in Japan and Korea for treatment of chronic hepatitis C virus (HCV) genotype 1. Response to DCV + ASV is affected by DCV resistance-associated polymorphisms (RAPs) in HCV NS5A. The prevalence and influence of these RAPs on 12-week sustained virologic response (SVR12) to DCV + ASV was evaluated in Asian and non-Asian patients. Methods Data were pooled from 5 national and international studies of patients with HCV genotype 1b (GT-1b) receiving DCV + ASV at their recommended doses. Baseline NS5A RAPs and their effect on SVR12 were assessed overall, in older (≥65 years) patients, patients with cirrhosis, and in patients stratified by baseline HCV RNA or prior treatment experience with interferon-based therapy. Results Baseline NS5A sequences were available from 988 patients (374 Japanese; 125 Korean/Taiwanese; 489 from non-Asian countries), 979 of whom were assessed for SVR12. Pretreatment NS5A-L31F/I/M/V and/or NS5A-Y93H polymorphisms were present in 18% of Japanese and 12–13% of non-Japanese patients; these RAPs reduced SVR12 by 54.9% overall (93.9% [787/838] SVR12 when absent, 39.0% [55/141] SVR12 when present), with comparable reductions observed in Asians and non-Asians and across all categories of treatment experience, age, and cirrhosis. RAP-associated SVR12 rates declined with increasing baseline HCV RNA (SVR12 with RAPs: 64.7% [11/17] at 5-6 log10 IU/mL, 29.8% [14/47] at 7–8 log10). Without baseline RAPs, very high SVR12 rates (92–100%) were observed in older patients and patients with cirrhosis irrespective of national origin, with similarly high rates observed among treatment-naïve and interferon-experienced patients and those with high baseline HCV RNA. Conclusions Following DCV + ASV treatment, the SVR12 rates in GT-1b patients without baseline NS5A-L31F/I/M/V and/or NS5A-Y93H polymorphisms were very high (approximately 90–100%), irrespective of age, cirrhosis, prior interferon treatment, or baseline HCV RNA. Funding Bristol-Myers Squibb. Electronic supplementary material The online version of this article (doi:10.1007/s12325-015-0221-5) contains supplementary material, which is available to authorized users.

BMS-488043 is a small-molecule human immunodeficiency virus type 1 (HIV-1) CD4 attachment inhibitor with demonstrated clinical efficacy. The compound inhibits soluble CD4 (sCD4) binding to the 11 distinct HIV envelope gp120 proteins surveyed. Binding of BMS-488043 and that of sCD4 to gp120 are mutually exclusive, since increased concentrations of one can completely block the binding of the other without affecting the maximal gp120 binding capacity. Similarly, BMS-488043 inhibited virion envelope trimers from binding to sCD4-immunoglobulin G (IgG), with decreasing inhibition as the sCD4-IgG concentration increased, and BMS-488043 blocked the sCD4-induced exposure of the gp41 groove in virions. In both virion binding assays, BMS-488043 was active only when added prior to sCD4. Collectively, these results indicate that obstruction of gp120-sCD4 interactions is the primary inhibition mechanism of this compound and that compound interaction with envelope must precede CD4 binding. By three independent approaches, BMS-488043 was further shown to induce conformational changes within gp120 in both the CD4 and CCR5 binding regions. These changes likely prevent gp120-CD4 interactions and downstream entry events. However, BMS-488043 could only partially inhibit CD4 binding to an HIV variant containing a specific envelope truncation and altered gp120 conformation, despite effectively inhibiting the pseudotyped virus infection. Taken together, BMS-488043 inhibits viral entry primarily through altering the envelope conformation and preventing CD4 binding, and other downstream entry events could also be inhibited as a result of these induced conformational changes.

BMS-378806 is a recently discovered small-molecule human immunodeficiency virus type 1 (HIV-1) attachment inhibitor with good antiviral activity and pharmacokinetic properties. Here, we demonstrate that the compound targets viral entry by inhibiting the binding of the HIV-1 envelope gp120 protein to cellular CD4 receptors via a specific and competitive mechanism. BMS-378806 binds directly to gp120 at a stoichiometry of approximately 1:1, with a binding affinity similar to that of soluble CD4. The potential BMS-378806 target site was localized to a specific region within the CD4 binding pocket of gp120 by using HIV-1 gp120 variants carrying either compound-selected resistant substitutions or gp120-CD4 contact site mutations. Mapping of resistance substitutions to the HIV-1 envelope, and the lack of compound activity against a CD4-independent viral infection confirm the gp120-CD4 interactions as the target in infected cells. BMS-378806 therefore serves as a prototype for this new class of antiretroviral agents and validates gp120 as a viable target for small-molecule inhibitors.

BMS-378806 is a recently discovered small molecule HIV-1 inhibitor that blocks viral entrance to cells. The compound exhibits potent inhibitory activity against a panel of R5-(virus using the CCR5 coreceptor), X4-(virus using the CXCR4 coreceptor), and R5/X4 HIV-1 laboratory and clinical isolates of the B subtype (median EC 50 of 0.04 μM) in culture assays. BMS-378806 is selective for HIV-1 and inactive against HIV-2, SIV and a panel of other viruses, and exhibits no significant cytotoxicity in the 14 cell types tested (concentration for 50% reduction of cell growth, >225 μM). Mechanism of action studies demonstrated that BMS-378806 binds to gp120 and inhibits the interactions of the HIV-1 envelope protein to cellular CD4 receptors. Further confirmation that BMS-378806 targets the envelope in infected cells was obtained through the isolation of resistant variants and the mapping of resistance substitutions to the HIV-1 envelope. In particular, two substitutions, M426L and M475I, are situated in the CD4 binding pocket of gp120. Recombinant HIV-1 carrying these two substitutions demonstrated significantly reduced susceptibility to compound inhibition. BMS-378806 displays many favorable pharmacological traits, such as low protein binding, minimal human serum effect on anti-HIV-1 potency, good oral bioavailability in animal species, and a clean safety profile in initial animal toxicology studies. Together, the data show that BMS-378806 is a representative of a new class of HIV inhibitors that has the potential to become a valued addition to our current armamentarium of antiretroviral drugs.

Plasmid-driven synthesis of viral RNA and protein allows the recovery of infectious influenza virus without the need for helper virus infection. Because no selection system is required for this approach, genetic manipulation of all eight viral gene segments without technical limitations is possible. We have developed a system which requires the construction and transfection of only eight plasmids for the recovery of influenza A viruses. In this DNA transfection system, viral cDNA is inserted between the human RNA polymerase I (pol I) promoter and murine terminator sequences. The entire pol I transcription unit is flanked by an RNA polymerase II (pol II) promoter and a poly(A) site. As a first step to evaluate the utility of this plasmid-based system for the production of vaccines, we generated the master strain A/PR/8/34 (H1N1) currently used for the production of inactivated vaccines entirely from cloned cDNAs. The virus yield as determined by HA-assay after passage of the recombinant virus in eggs was as high as the virus yield of the parental wild-type virus. These results prove that the generated recombinant virus has the same growth properties as the parental egg grown virus and indicate that the eight-plasmid transfection method has the potential to improve currently used methods for the production of vaccine viruses.

Background Daclatasvir (DCV; BMS-790052) is a picomolar inhibitor of HCV non-structural protein 5A (NS5A) and has demonstrated efficacy in patients chronically infected with HCV. Methods In the double-blind, randomized studies AI444021 and AI444022, 71 Japanese patients chronically infected with HCV genotype 1 (predominantly genotype 1b) received DCV (10 mg or 60 mg) plus peginterferon alfa-2b or alfa-2a and ribavirin. Virological failure occurred in 14% (5/36) of treatment-naive patients and 54% (19/35) of prior alfa/ribavirin non-responders. Resistance testing was performed on baseline samples and samples with HCV RNA≥1,000 IU/ml at week 1 through post-treatment week 24. Results Baseline NS5A resistance-associated polymorphisms had less impact on virological response rates than IL28B genotype. All patients with virological failure had NS5A DCV-resistant variants at the time of failure. The predominant NS5A variants were L31V/M/I plus Y93H; this combination was detected in 100% (5/5) of treatment-naive patients and 74% (14/19) of non-responders with failure. Emergent resistance variants in prior non-responders (four viral breakthroughs, one relapse) were more varied with novel combinations such as L31F-DP32 and L28M-R30Q-A92K detected. Significant loss in DCV antiviral activity was generally only seen with ≥ two resistance-associated NS5A substitutions. All DCV-resistant variants were still detected at end of study. Conclusions Virological failure in HCV genotype 1b treatment-naive Japanese patients receiving DCV plus alfa-2a/ribavirin or alfa-2b/ribavirin was associated with enrichment of NS5A resistance variants L31V/M-Y93H. In prior non-responders, emergent variants associated with failure also included NS5A-A92K or NS5A-DP32. As with L31-Y93 variants, these variants persisted.

Organic cation transporter 2 (OCT2) is responsible for the entry step of many drugs in renal elimination, of which the changing activity may cause unwanted drug-drug interactions (DDIs). To develop drugs with favorable safety profile and provide instruction for rational clinical drug administration, it is of great interest to investigate the multiple mechanisms of OCT2 inhibition. In this study, we designed a combinatorial scheme to screen the optimum combination of pharmacophores from a pool of hypotheses established based on 162 OCT2 inhibitors. Among them, one single pharmacophore hypothesis represents a potential binding mode that may account for one unique inhibitory mechanism, and the obtained pharmacophore combination describes the multimechanisms of OCT2 inhibition. The final model consists of four individual pharmacophores, i.e., DHPR18, APR2, PRR5 and HHR4. Given a query ligand, it is considered as an inhibitor if it matches at least one of the hypotheses, or a noninhibitor if it fails to match any of four hypotheses. Our combinatorial pharmacophore model performs reasonably well to discriminate inhibitors and noninhibitors, yielding an overall accuracy around 0.70 for a test set containing 81 OCT2 inhibitors and 218 noninhibitors. Intriguingly, we found that the number of matched hypotheses was positively correlated with inhibition rate, which coincides with the pharmacophore modeling result of P-gp substrate binding. Further analysis suggested that the hypothesis PRR5 was responsible for competitive inhibition of OCT2, and other hypotheses were important for interaction between the inhibitor and OCT2. In light of the results, a hypothetical model for inhibiting transporting mediated by OCT2 was proposed.