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Sample records for high-throughput antimalarial drug

  1. High-throughput matrix screening identifies synergistic and antagonistic antimalarial drug combinations

    PubMed Central

    Mott, Bryan T.; Eastman, Richard T.; Guha, Rajarshi; Sherlach, Katy S.; Siriwardana, Amila; Shinn, Paul; McKnight, Crystal; Michael, Sam; Lacerda-Queiroz, Norinne; Patel, Paresma R.; Khine, Pwint; Sun, Hongmao; Kasbekar, Monica; Aghdam, Nima; Fontaine, Shaun D.; Liu, Dongbo; Mierzwa, Tim; Mathews-Griner, Lesley A.; Ferrer, Marc; Renslo, Adam R.; Inglese, James; Yuan, Jing; Roepe, Paul D.; Su, Xin-zhuan; Thomas, Craig J.

    2015-01-01

    Drug resistance in Plasmodium parasites is a constant threat. Novel therapeutics, especially new drug combinations, must be identified at a faster rate. In response to the urgent need for new antimalarial drug combinations we screened a large collection of approved and investigational drugs, tested 13,910 drug pairs, and identified many promising antimalarial drug combinations. The activity of known antimalarial drug regimens was confirmed and a myriad of new classes of positively interacting drug pairings were discovered. Network and clustering analyses reinforced established mechanistic relationships for known drug combinations and identified several novel mechanistic hypotheses. From eleven screens comprising >4,600 combinations per parasite strain (including duplicates) we further investigated interactions between approved antimalarials, calcium homeostasis modulators, and inhibitors of phosphatidylinositide 3-kinases (PI3K) and the mammalian target of rapamycin (mTOR). These studies highlight important targets and pathways and provide promising leads for clinically actionable antimalarial therapy. PMID:26403635

  2. Automated High Throughput Drug Target Crystallography

    SciTech Connect

    Rupp, B

    2005-02-18

    The molecular structures of drug target proteins and receptors form the basis for 'rational' or structure guided drug design. The majority of target structures are experimentally determined by protein X-ray crystallography, which as evolved into a highly automated, high throughput drug discovery and screening tool. Process automation has accelerated tasks from parallel protein expression, fully automated crystallization, and rapid data collection to highly efficient structure determination methods. A thoroughly designed automation technology platform supported by a powerful informatics infrastructure forms the basis for optimal workflow implementation and the data mining and analysis tools to generate new leads from experimental protein drug target structures.

  3. Development and Optimization of a Novel 384-Well Anti-Malarial Imaging Assay Validated for High-Throughput Screening

    PubMed Central

    Duffy, Sandra; Avery, Vicky M.

    2012-01-01

    With the increasing occurrence of drug resistance in the malaria parasite, Plasmodium falciparum, there is a great need for new and novel anti-malarial drugs. We have developed a 384-well, high-throughput imaging assay for the detection of new anti-malarial compounds, which was initially validated by screening a marine natural product library, and subsequently used to screen more than 3 million data points from a variety of compound sources. Founded on another fluorescence-based P. falciparum growth inhibition assay, the DNA-intercalating dye 4′,6-diamidino-2-phenylindole, was used to monitor changes in parasite number. Fluorescent images were acquired on the PerkinElmer Opera High Throughput confocal imaging system and analyzed with a spot detection algorithm using the Acapella data processing software. Further optimization of this assay sought to increase throughput, assay stability, and compatibility with our high-throughput screening equipment platforms. The assay typically yielded Z'-factor values of 0.5–0.6, with signal-to-noise ratios of 12. PMID:22232455

  4. C. elegans in high-throughput drug discovery

    PubMed Central

    O’Reilly, Linda P.; Luke, Cliff J.; Perlmutter, David H.; Silverman, Gary A.; Pak, Stephen C.

    2014-01-01

    C. elegans has proven to be a useful model organism for investigating molecular and cellular aspects of numerous human diseases. More recently, investigators have explored the use of this organism as a tool for drug discovery. Although earlier drug screens were labor-intensive and low in throughput, recent advances in high-throughput liquid workflows, imaging platforms and data analysis software have made C. elegans a viable option for automated high-throughput drug screens. This review will outline the evolution of C. elegans-based drug screening, discuss the inherent challenges of using C. elegans, and highlight recent technological advances that have paved the way for future drug screens. PMID:24333896

  5. Antimalarial drug resistance: An overview

    PubMed Central

    Antony, Hiasindh Ashmi; Parija, Subhash Chandra

    2016-01-01

    Malaria is a major public health burden throughout the world. Resistance to the antimalarial drugs has increased the mortality and morbidity rate that is achieved so far through the malaria control program. Monitoring the drug resistance to the available antimalarial drugs helps to implement effective drug policy, through the in vivo efficacy studies, in vitro drug susceptibility tests and detection of molecular markers. It is important to understand the mechanism of the antimalarial drugs, as it is one of the key factors in the emergence and spread of drug resistance. This review summarizes the commonly used antimalarial drugs, their mechanism of action and the genetic markers validated so far for the detection of drug-resistant parasites. PMID:26998432

  6. [Resistance to the antimalarial drugs].

    PubMed

    Venanzi, E; López-Vélez, R

    2016-09-01

    Malaria is one of the most widespread infectious diseases around the world with 214 million cases and 438,000 deaths in 2015. In the early twentieth century it was described for the first time the resistance to quinine and, since then, drug resistance to antimalarial drugs has spread up to represent a global challenge in the fight and control of malaria. Understanding the mechanisms, geography and monitoring tools that we can act against resistance to antimalarial drugs is critical to prevent its expansion. PMID:27608319

  7. High-throughput crystallography for lead discovery in drug design.

    PubMed

    Blundell, Tom L; Jhoti, Harren; Abell, Chris

    2002-01-01

    Knowledge of the three-dimensional structures of protein targets now emerging from genomic data has the potential to accelerate drug discovery greatly. X-ray crystallography is the most widely used technique for protein structure determination, but technical challenges and time constraints have traditionally limited its use primarily to lead optimization. Here, we describe how significant advances in process automation and informatics have aided the development of high-throughput X-ray crystallography, and discuss the use of this technique for structure-based lead discovery.

  8. Microfluidic cell chips for high-throughput drug screening.

    PubMed

    Chi, Chun-Wei; Ahmed, Ah Rezwanuddin; Dereli-Korkut, Zeynep; Wang, Sihong

    2016-05-01

    The current state of screening methods for drug discovery is still riddled with several inefficiencies. Although some widely used high-throughput screening platforms may enhance the drug screening process, their cost and oversimplification of cell-drug interactions pose a translational difficulty. Microfluidic cell-chips resolve many issues found in conventional HTS technology, providing benefits such as reduced sample quantity and integration of 3D cell culture physically more representative of the physiological/pathological microenvironment. In this review, we introduce the advantages of microfluidic devices in drug screening, and outline the critical factors which influence device design, highlighting recent innovations and advances in the field including a summary of commercialization efforts on microfluidic cell chips. Future perspectives of microfluidic cell devices are also provided based on considerations of present technological limitations and translational barriers. PMID:27071838

  9. High-throughput protein crystallography and drug discovery.

    PubMed

    Tickle, Ian; Sharff, Andrew; Vinkovic, Mladen; Yon, Jeff; Jhoti, Harren

    2004-10-20

    Single crystal X-ray diffraction is the technique of choice for studying the interactions of small organic molecules with proteins by determining their three-dimensional structures; however the requirement for highly purified protein and lack of process automation have traditionally limited its use in this field. Despite these shortcomings, the use of crystal structures of therapeutically relevant drug targets in pharmaceutical research has increased significantly over the last decade. The application of structure-based drug design has resulted in several marketed drugs and is now an established discipline in most pharmaceutical companies. Furthermore, the recently published full genome sequences of Homo sapiens and a number of micro-organisms have provided a plethora of new potential drug targets that could be utilised in structure-based drug design programs. In order to take maximum advantage of this explosion of information, techniques have been developed to automate and speed up the various procedures required to obtain protein crystals of suitable quality, to collect and process the raw X-ray diffraction data into usable structural information, and to use three-dimensional protein structure as a basis for drug discovery and lead optimisation. This tutorial review covers the various technologies involved in the process pipeline for high-throughput protein crystallography as it is currently being applied to drug discovery. It is aimed at synthetic and computational chemists, as well as structural biologists, in both academia and industry, who are interested in structure-based drug design.

  10. High-throughput virtual screening for drug discovery in parallel.

    PubMed

    Toledo-Sherman, Leticia M; Chen, Deqi

    2002-05-01

    With the influx of targets generated by genomics and proteomics initiatives, a new drug discovery paradigm is emerging. Many companies are setting up target family platforms that tackle multiple targets and therapeutic areas simultaneously. Virtual screening (VS) techniques are a fundamental component of such platforms for in silico filtering of compound collections and prioritization of chemistry and screening efforts. At the heart of these, structure-based docking and scoring methods are especially effective in identifying bioactive molecules if the structure of a target is available. As structural genomics maps the structural space of the proteome, these techniques are expected to become commonplace. In light of this, an overview of the latest developments in VS methodology is given here. In particular, emphasis is placed on those techniques adaptable to high-throughput VS in parallel drug discovery platforms. The first examples of docking across multiple targets have already appeared in the literature and will be reviewed here.

  11. Miniaturized Cultivation of Microbiota for Antimalarial Drug Discovery.

    PubMed

    Waterman, Carrie; Calcul, Laurent; Beau, Jeremy; Ma, Wai Sheung; Lebar, Matthew D; von Salm, Jacqueline L; Harter, Charles; Mutka, Tina; Morton, Lindsay C; Maignan, Patrick; Barisic, Betty; van Olphen, Alberto; Kyle, Dennis E; Vrijmoed, Lilian; Pang, Ka-Lai; Pearce, Cedric J; Baker, Bill J

    2016-01-01

    The ongoing search for effective antiplasmodial agents remains essential in the fight against malaria worldwide. Emerging parasitic drug resistance places an urgent need to explore chemotherapies with novel structures and mechanisms of action. Natural products have historically provided effective antimalarial drug scaffolds. In an effort to search nature's chemical potential for antiplasmodial agents, unconventionally sourced organisms coupled with innovative cultivation techniques were utilized. Approximately 60,000 niche microbes from various habitats (slow-growing terrestrial fungi, Antarctic microbes, and mangrove endophytes) were cultivated on a small-scale, extracted, and used in high-throughput screening to determine antimalarial activity. About 1% of crude extracts were considered active and 6% partially active (≥ 67% inhibition at 5 and 50 μg/mL, respectively). Active extracts (685) were cultivated on a large-scale, fractionated, and screened for both antimalarial activity and cytotoxicity. High interest fractions (397) with an IC50 < 1.11 μg/mL were identified and subjected to chromatographic separation for compound characterization and dereplication. Identifying active compounds with nanomolar antimalarial activity coupled with a selectivity index tenfold higher was accomplished with two of the 52 compounds isolated. This microscale, high-throughput screening project for antiplasmodial agents is discussed in the context of current natural product drug discovery efforts.

  12. Miniaturized Cultivation of Microbiota for Antimalarial Drug Discovery.

    PubMed

    Waterman, Carrie; Calcul, Laurent; Beau, Jeremy; Ma, Wai Sheung; Lebar, Matthew D; von Salm, Jacqueline L; Harter, Charles; Mutka, Tina; Morton, Lindsay C; Maignan, Patrick; Barisic, Betty; van Olphen, Alberto; Kyle, Dennis E; Vrijmoed, Lilian; Pang, Ka-Lai; Pearce, Cedric J; Baker, Bill J

    2016-01-01

    The ongoing search for effective antiplasmodial agents remains essential in the fight against malaria worldwide. Emerging parasitic drug resistance places an urgent need to explore chemotherapies with novel structures and mechanisms of action. Natural products have historically provided effective antimalarial drug scaffolds. In an effort to search nature's chemical potential for antiplasmodial agents, unconventionally sourced organisms coupled with innovative cultivation techniques were utilized. Approximately 60,000 niche microbes from various habitats (slow-growing terrestrial fungi, Antarctic microbes, and mangrove endophytes) were cultivated on a small-scale, extracted, and used in high-throughput screening to determine antimalarial activity. About 1% of crude extracts were considered active and 6% partially active (≥ 67% inhibition at 5 and 50 μg/mL, respectively). Active extracts (685) were cultivated on a large-scale, fractionated, and screened for both antimalarial activity and cytotoxicity. High interest fractions (397) with an IC50 < 1.11 μg/mL were identified and subjected to chromatographic separation for compound characterization and dereplication. Identifying active compounds with nanomolar antimalarial activity coupled with a selectivity index tenfold higher was accomplished with two of the 52 compounds isolated. This microscale, high-throughput screening project for antiplasmodial agents is discussed in the context of current natural product drug discovery efforts. PMID:25545963

  13. High-throughput process development for biopharmaceutical drug substances.

    PubMed

    Bhambure, Rahul; Kumar, Kaushal; Rathore, Anurag S

    2011-03-01

    Quality by Design (QbD) is gaining industry acceptance as an approach towards development and commercialization of biotechnology therapeutic products that are expressed via microbial or mammalian cell lines. In QbD, the process is designed and controlled to deliver specified quality attributes consistently. To acquire the enhanced understanding that is necessary to achieve the above, however, requires more extensive experimentation to establish the design space for the process and the product. With biotechnology companies operating under ever-increasing pressure towards lowering the cost of manufacturing, the use of high-throughput tools has emerged as a necessary enabler of QbD in a time- and resource-constrained environment. We review this topic for those in academia and industry that are engaged in drug substance process development.

  14. High Throughput Screening for Drugs that Modulate Intermediate Filament Proteins

    PubMed Central

    Sun, Jingyuan; Groppi, Vincent E.; Gui, Honglian; Chen, Lu; Xie, Qing; Liu, Li

    2016-01-01

    Intermediate filament (IF) proteins have unique and complex cell and tissue distribution. Importantly, IF gene mutations cause or predispose to more than 80 human tissue-specific diseases (IF-pathies), with the most severe disease phenotypes being due to mutations at conserved residues that result in a disrupted IF network. A critical need for the entire IF-pathy field is the identification of drugs that can ameliorate or cure these diseases, particularly since all current therapies target the IF-pathy complication, such as diabetes or cardiovascular disease, rather than the mutant IF protein or gene. We describe a high throughput approach to identify drugs that can normalize disrupted IF proteins. This approach utilizes transduction of lentivirus that expresses green-fluorescent-protein-tagged keratin 18 (K18) R90C in A549 cells. The readout is drug ‘hits’ that convert the dot-like keratin filament distribution, due to the R90C mutation, to a wildtype-like filamentous array. A similar strategy can be used to screen thousands of compounds and can be utilized for practically any IF protein with a filament-disrupting mutation, and could therefore potentially target many IF-pathies. ‘Hits’ of interest require validation in cell culture then using in vivo experimental models. Approaches to study the mechanism of mutant-IF normalization by potential drugs of interest are also described. The ultimate goal of this drug screening approach is to identify effective and safe compounds that can potentially be tested for clinical efficacy in patients. PMID:26795471

  15. High-throughput screening technologies for drug glucuronidation profiling.

    PubMed

    Trubetskoy, Olga; Finel, Moshe; Trubetskoy, Vladimir

    2008-08-01

    A significant number of endogenous and exogenous compounds, including many therapeutic agents, are metabolized in humans via glucuronidation, catalysed by uridine diphosphoglucuronosyltransferases (UGTs). The study of the UGTs is a growing field of research, with constantly accumulated and updated information regarding UGT structure, purification, substrate specificity and inhibition, including clinically relevant drug interactions. Development of reliable UGT assays for the assessment of individual isoform substrate specificity and for the discovery of novel isoform-specific substrates and inhibitors is crucial for understanding the function and regulation of the UGT enzyme family and its clinical and pharmacological relevance. High-throughput screening (HTS) is a powerful technology used to search for novel substrates and inhibitors for a wide variety of targets. However, application of HTS in the context of UGTs is complicated because of the poor stability, low levels of expression, low affinity and broad substrate specificity of the enzymes, combined with difficulties in obtaining individual UGT isoforms in purified format, and insufficient information regarding isoform-specific substrates and inhibitors. This review examines the current status of HTS assays used in the search for novel UGT substrates and inhibitors, emphasizing advancements and challenges in HTS technologies for drug glucuronidation profiling, and discusses possible avenues for future advancement of the field.

  16. World Antimalarial Resistance Network I: clinical efficacy of antimalarial drugs.

    PubMed

    Price, Ric N; Dorsey, Grant; Ashley, Elizabeth A; Barnes, Karen I; Baird, J Kevin; d'Alessandro, Umberto; Guerin, Philippe J; Laufer, Miriam K; Naidoo, Inbarani; Nosten, François; Olliaro, Piero; Plowe, Christopher V; Ringwald, Pascal; Sibley, Carol H; Stepniewska, Kasia; White, Nicholas J

    2007-01-01

    The proliferation of antimalarial drug trials in the last ten years provides the opportunity to launch a concerted global surveillance effort to monitor antimalarial drug efficacy. The diversity of clinical study designs and analytical methods undermines the current ability to achieve this. The proposed World Antimalarial Resistance Network (WARN) aims to establish a comprehensive clinical database from which standardised estimates of antimalarial efficacy can be derived and monitored over time from diverse geographical and endemic regions. The emphasis of this initiative is on five key variables which define the therapeutic response. Ensuring that these data are collected at the individual patient level in a consistent format will facilitate better data management and analytical practices, and ensure that clinical data can be readily collated and made amenable for pooled analyses. Such an approach, if widely adopted will permit accurate and timely recognition of trends in drug efficacy. This will guide not only appropriate interventions to deal with established multidrug resistant strains of malaria, but also facilitate prompt action when new strains of drug resistant plasmodia first emerge. A comprehensive global database incorporating the key determinants of the clinical response with in vitro, molecular and pharmacokinetic parameters will bring together relevant data on host, drug and parasite factors that are fundamental contributors to treatment efficacy. This resource will help guide rational drug policies that optimize antimalarial drug use, in the hope that the emergence and spread of resistance to new drugs can be, if not prevented, at least delayed.

  17. Cell-based medicinal chemistry optimization of high-throughput screening (HTS) hits for orally active antimalarials. Part 1: challenges in potency and absorption, distribution, metabolism, excretion/pharmacokinetics (ADME/PK).

    PubMed

    Chatterjee, Arnab K

    2013-10-24

    Malaria represents a significant health issue, and novel and effective drugs are needed to address parasite resistance that has emerged to the current drug arsenal. Antimalarial drug discovery has historically benefited from a whole-cell (phenotypic) screening approach to identify lead molecules. This approach has been utilized by several groups to optimize weakly active antimalarial pharmacophores, such as the quinolone scaffold, to yield potent and highly efficacious compounds that are now poised to enter clinical trials. More recently, GNF/Novartis, GSK, and others have employed the same approach in high-throughput screening (HTS) of large compound libraries to find novel scaffolds that have also been optimized to clinical candidates by GNF/Novartis. This perspective outlines some of the inherent challenges in cell-based medicinal chemistry optimization, including optimization of oral exposure and hERG activity.

  18. High-throughput flow cytometry for drug discovery.

    PubMed

    Edwards, Bruce S; Young, Susan M; Saunders, Matthew J; Bologa, Cristian; Oprea, Tudor I; Ye, Richard D; Prossnitz, Eric R; Graves, Steven W; Sklar, Larry A

    2007-05-01

    High-throughput flow cytometry exploits a novel many-samples/one-file approach to dramatically speed data acquisition, limit aspirated sample volume to as little as 2 μl/well and produce multisample data sets that facilitate automated analysis of samples in groups as well as individually. It has been successfully applied to both cell- and microsphere-based bioassays in 96- and 384-well formats, to screen tens-of-thousands of compounds and identify novel bioactive structures. High-content multiparametric analysis capabilities have been exploited for assay multiplexing, allowing the assessment of biologic selectivity and specificity to be an integral component of primary screens. These and other advances in the last decade have contributed to the application of flow cytometry as a uniquely powerful tool for probing biologic and chemical diversity and complex systems biology.

  19. A High-Throughput Screen for Antibiotic Drug Discovery

    PubMed Central

    Scanlon, Thomas C.; Dostal, Sarah M.; Griswold, Karl E.

    2014-01-01

    We describe an ultra-high-throughput screening platform enabling discovery and/or engineering of natural product antibiotics. The methodology involves creation of hydrogel-in-oil emulsions in which recombinant microorganisms are co-emulsified with bacterial pathogens; antibiotic activity is assayed by use of a fluorescent viability dye. We have successfully utilized both bulk emulsification and microfluidic technology for the generation of hydrogel microdroplets that are size-compatible with conventional flow cytometry. Hydrogel droplets are ~25 pL in volume, and can be synthesized and sorted at rates exceeding 3,000 drops/s. Using this technique, we have achieved screening throughputs exceeding 5 million clones/day. Proof-of-concept experiments demonstrate efficient selection of antibiotic-secreting yeast from a vast excess of negative controls. In addition, we have successfully used this technique to screen a metagenomic library for secreted antibiotics that kill the human pathogen Staphylococcus aureus. Our results establish the practical utility of the screening platform, and we anticipate that the accessible nature of our methods will enable others seeking to identify and engineer the next generation of antibacterial biomolecules. PMID:23955804

  20. High-Throughput Screening of Ototoxic and Otoprotective Pharmacological Drugs

    ERIC Educational Resources Information Center

    Kalinec, Federico

    2005-01-01

    Drug ototoxicity research has relied traditionally on animal models for the discovery and development of therapeutic interventions. More than 50 years of research, however, has delivered few--if any--successful clinical strategies for preventing or ameliorating the ototoxic effects of common pharmacological drugs such as aminoglycoside…

  1. Emerging high-throughput drug target validation technologies.

    PubMed

    Ilag, Leodevico L; Ng, Jocelyn H; Beste, Gerald; Henning, Stefan W

    2002-09-15

    Identifying the right target for drug development is a critical bottleneck in the pharmaceutical and biotech industries. The genomics revolution has shifted the problem from a scarcity of targets to a surplus of putative drug targets. As the validity of a target cannot be simply inferred from correlative data, the key is confirmation of the causative role of a gene product in a particular disease. It should therefore be recognized that an effective therapeutic strategy requires an appropriate target validation technology to verify the right target.

  2. Review article: high-throughput affinity-based technologies for small-molecule drug discovery.

    PubMed

    Zhu, Zhengrong; Cuozzo, John

    2009-12-01

    High-throughput affinity-based technologies are rapidly growing in use as primary screening methods in drug discovery. In this review, their principles and applications are described and their impact on small-molecule drug discovery is evaluated. In general, these technologies can be divided into 2 groups: those that detect binding interactions by measuring changes to the protein target and those that detect bound compounds. Technologies detecting binding interactions by focusing on the protein have limited throughput but can reveal mechanistic information about the binding interaction; technologies detecting bound compounds have very high throughput, some even significantly higher than current high-throughput screening technologies, but offer limited information about the binding interaction. In addition, the appropriate use of affinity-based technologies is discussed. Finally, nanotechnology is predicted to generate a significant impact on the future of affinity-based technologies. PMID:19822881

  3. High-throughput screening approaches for investigating drug metabolism and pharmacokinetics.

    PubMed

    Roberts, S A

    2001-01-01

    1. High-throughput screening approaches have been adopted throughout the pharmaceutical industry to aid in the rapid discovery of new chemical entities. Because it is now well recognized that the selection of a robust candidate requires a balance of potency, safety and pharmacokinetics, the role of drug metabolism departments has widened from their traditional one of supporting drug development to include the screening of compounds during the discovery process. To put drug metabolism and pharmacokinetic (DMPK) studies in context, the evolving role of DMPK screening in the drug discovery strategy of pharmaceutical companies will be discussed and a generalized approach will be presented. 2. With the increasing numbers of compounds requiring screening, DMPK optimization methods have had to be adapted for high throughput. There have been many developments in this field over the past decade and this review will focus on the high-throughput DMPK screening methodologies used today and in the recent past. 3. In vitro and in silico (computer-based) methods have proven most amenable to high-throughput approaches and these will firm the bulk of the review, but some advances with in vivo methods will also be discussed. As there has been a vast increase in published material on the topic of high-throughput DMPK methodologies in the past 10 years, it would be impossible to cover every method in detail, so this review will concentrate on the key areas and refer the reader to other, more detailed reviews wherever possible. 4. Most high-throughput methods would not be possible without the enabling technologies of computing, automation, new sample preparation technologies, and highly sensitive and selective detection systems, and these will also be reviewed. 5. The advantages and disadvantages of the screening methods will be presented, in particular the issue of handling the false-positives and -negatives that arise. 6. In concluding the review, future developments in this field

  4. Antimalarial drug resistance and combination chemotherapy.

    PubMed Central

    White, N

    1999-01-01

    Antimarial drug resistance develops when spontaneously occurring parasite mutants with reduced susceptibility are selected, and are then transmitted. Drugs for which a single point mutation confers a marked reduction in susceptibility are particularly vulnerable. Low clearance and a shallow concentration-effect relationship increase the chance of selection. Use of combinations of antimalarials that do not share the same resistance mechanisms will reduce the chance of selection because the chance of a resistant mutant surviving is the product of the per parasite mutation rates for the individual drugs, multiplied by the number of parasites in an infection that are exposed to the drugs. Artemisinin derivatives are particularly effective combination partners because (i) they are very active antimalarials, producing up to 10,000-fold reductions in parasite biomass per asexual cycle; (ii) they reduce malaria transmissibility; and (iii) no resistance to these drugs has been reported yet. There are good arguments for no longer using antimalarial drugs alone in treatment, and instead always using a combination with artemisinin or one of its derivatives. PMID:10365399

  5. Pricing, distribution, and use of antimalarial drugs.

    PubMed Central

    Foster, S. D.

    1991-01-01

    Prices of new antimalarial drugs are targeted at the "travellers' market" in developed countries, which makes them unaffordable in malaria-endemic countries where the per capita annual drug expenditures are US$ 5 or less. Antimalarials are distributed through a variety of channels in both public and private sectors, the official malaria control programmes accounting for 25-30% of chloroquine distribution. The unofficial drug sellers in markets, streets, and village shops account for as much as half of antimalarials distributed in many developing countries. Use of antimalarials through the health services is often poor; drug shortages are common and overprescription and overuse of injections are significant problems. Anxiety over drug costs may prevent patients from getting the necessary treatment for malaria, especially because of the seasonal appearance of this disease when people's cash reserves are very low. The high costs may lead them to unofficial sources, which will sell a single tablet instead of a complete course of treatment, and subsequently to increased, often irrational demand for more drugs and more injections. Increasingly people are resorting to self-medication for malaria, which may cause delays in seeking proper treatment in cases of failure, especially in areas where chloroquine resistance has increased rapidly. Self-medication is now widespread, and measures to restrict the illicit sale of drugs have been unsuccessful. The "unofficial" channels thus represent an unacknowledged extension of the health services in many countries; suggestions are advanced to encourage better self-medication by increasing the knowledge base among the population at large (mothers, schoolchildren, market sellers, and shopkeepers), with an emphasis on correct dosing and on the importance of seeking further treatment without delay, if necessary. PMID:1893512

  6. Evaluation of high-throughput assays for in vitro drug susceptibility testing of Tritrichomonas foetus trophozoites.

    PubMed

    Bader, Chris; Jesudoss Chelladurai, Jeba; Thompson, Kylie; Hall, Cindy; Carlson, Steve A; Brewer, Matthew T

    2016-06-15

    Tritrichomonas foetus is a sexually transmitted protozoan parasite that causes abortions in cattle and results in severe economic losses. In the United States, there are no safe and effective treatments for this parasite and infected animals are typically culled. In order to expedite drug discovery efforts, we investigated in vitro trophozoite killing assays amenable to high-throughput screening in 96 well plate formats. We evaluated the reduction of resorufin, incorporation of propidium iodide, and a luminescence-based ATP detection assay. Of these methods, reduction of resorufin was found to be the most reliable predictor of trophozoite concentrations. We further validated this method by conducting dose-response experiments suitable for calculation of EC50 values for two established compounds with known activity against trophozoites in vitro, namely, metronidazole and ronidazole. Our results demonstrate that the resorufin method is suitable for high-throughput screening and could be used to enhance efforts targeting new treatments for bovine trichomoniasis. PMID:27198774

  7. Expanding the Antimalarial Drug Arsenal-Now, But How?

    PubMed

    Grimberg, Brian T; Mehlotra, Rajeev K

    2011-05-01

    The number of available and effective antimalarial drugs is quickly dwindling. This is mainly because a number of drug resistance-associated mutations in malaria parasite genes, such as crt, mdr1, dhfr/dhps, and others, have led to widespread resistance to all known classes of antimalarial compounds. Unfortunately, malaria parasites have started to exhibit some level of resistance in Southeast Asia even to the most recently introduced class of drugs, artemisinins. While there is much need, the antimalarial drug development pipeline remains woefully thin, with little chemical diversity, and there is currently no alternative to the precious artemisinins. It is difficult to predict where the next generation of antimalarial drugs will come from; however, there are six major approaches: (i) re-optimizing the use of existing antimalarials by either replacement/rotation or combination approach; (ii) repurposing drugs that are currently used to treat other infections or diseases; (iii) chemically modifying existing antimalarial compounds; (iv) exploring natural sources; (v) large-scale screening of diverse chemical libraries; and (vi) through parasite genome-based ("targeted") discoveries. When any newly discovered effective antimalarial treatment is used by the populus, we must maintain constant vigilance for both parasite-specific and human-related factors that are likely to hamper its success. This article is neither comprehensive nor conclusive. Our purpose is to provide an overview of antimalarial drug resistance, associated parasite genetic factors (1. Introduction; 2. Emergence of artemisinin resistance in P. falciparum), and the antimalarial drug development pipeline (3. Overview of the global pipeline of antimalarial drugs), and highlight some examples of the aforementioned approaches to future antimalarial treatment. These approaches can be categorized into "short term" (4. Feasible options for now) and "long term" (5. Next generation of antimalarial treatment

  8. Expanding the Antimalarial Drug Arsenal—Now, But How?

    PubMed Central

    Grimberg, Brian T.; Mehlotra, Rajeev K.

    2011-01-01

    The number of available and effective antimalarial drugs is quickly dwindling. This is mainly because a number of drug resistance-associated mutations in malaria parasite genes, such as crt, mdr1, dhfr/dhps, and others, have led to widespread resistance to all known classes of antimalarial compounds. Unfortunately, malaria parasites have started to exhibit some level of resistance in Southeast Asia even to the most recently introduced class of drugs, artemisinins. While there is much need, the antimalarial drug development pipeline remains woefully thin, with little chemical diversity, and there is currently no alternative to the precious artemisinins. It is difficult to predict where the next generation of antimalarial drugs will come from; however, there are six major approaches: (i) re-optimizing the use of existing antimalarials by either replacement/rotation or combination approach; (ii) repurposing drugs that are currently used to treat other infections or diseases; (iii) chemically modifying existing antimalarial compounds; (iv) exploring natural sources; (v) large-scale screening of diverse chemical libraries; and (vi) through parasite genome-based (“targeted”) discoveries. When any newly discovered effective antimalarial treatment is used by the populus, we must maintain constant vigilance for both parasite-specific and human-related factors that are likely to hamper its success. This article is neither comprehensive nor conclusive. Our purpose is to provide an overview of antimalarial drug resistance, associated parasite genetic factors (1. Introduction; 2. Emergence of artemisinin resistance in P. falciparum), and the antimalarial drug development pipeline (3. Overview of the global pipeline of antimalarial drugs), and highlight some examples of the aforementioned approaches to future antimalarial treatment. These approaches can be categorized into “short term” (4. Feasible options for now) and “long term” (5. Next generation of antimalarial

  9. Engineering a Brain Cancer Chip for High-throughput Drug Screening.

    PubMed

    Fan, Yantao; Nguyen, Duong Thanh; Akay, Yasemin; Xu, Feng; Akay, Metin

    2016-01-01

    Glioblastoma multiforme (GBM) is the most common and malignant of all human primary brain cancers, in which drug treatment is still one of the most effective treatments. However, existing drug discovery and development methods rely on the use of conventional two-dimensional (2D) cell cultures, which have been proven to be poor representatives of native physiology. Here, we developed a novel three-dimensional (3D) brain cancer chip composed of photo-polymerizable poly(ethylene) glycol diacrylate (PEGDA) hydrogel for drug screening. This chip can be produced after a few seconds of photolithography and requires no silicon wafer, replica molding, and plasma bonding like microfluidic devices made of poly(dimethylsiloxane) (PDMS). We then cultured glioblastoma cells (U87), which formed 3D brain cancer tissues on the chip, and used the GBM chip to perform combinatorial treatment of Pitavastatin and Irinotecan. The results indicate that this chip is capable of high-throughput GBM cancer spheroids formation, multiple-simultaneous drug administration, and a massive parallel testing of drug response. Our approach is easily reproducible, and this chip has the potential to be a powerful platform in cases such as high-throughput drug screening and prolonged drug release. The chip is also commercially promising for other clinical applications, including 3D cell culture and micro-scale tissue engineering. PMID:27151082

  10. Engineering a Brain Cancer Chip for High-throughput Drug Screening.

    PubMed

    Fan, Yantao; Nguyen, Duong Thanh; Akay, Yasemin; Xu, Feng; Akay, Metin

    2016-05-06

    Glioblastoma multiforme (GBM) is the most common and malignant of all human primary brain cancers, in which drug treatment is still one of the most effective treatments. However, existing drug discovery and development methods rely on the use of conventional two-dimensional (2D) cell cultures, which have been proven to be poor representatives of native physiology. Here, we developed a novel three-dimensional (3D) brain cancer chip composed of photo-polymerizable poly(ethylene) glycol diacrylate (PEGDA) hydrogel for drug screening. This chip can be produced after a few seconds of photolithography and requires no silicon wafer, replica molding, and plasma bonding like microfluidic devices made of poly(dimethylsiloxane) (PDMS). We then cultured glioblastoma cells (U87), which formed 3D brain cancer tissues on the chip, and used the GBM chip to perform combinatorial treatment of Pitavastatin and Irinotecan. The results indicate that this chip is capable of high-throughput GBM cancer spheroids formation, multiple-simultaneous drug administration, and a massive parallel testing of drug response. Our approach is easily reproducible, and this chip has the potential to be a powerful platform in cases such as high-throughput drug screening and prolonged drug release. The chip is also commercially promising for other clinical applications, including 3D cell culture and micro-scale tissue engineering.

  11. Engineering a Brain Cancer Chip for High-throughput Drug Screening

    PubMed Central

    Fan, Yantao; Nguyen, Duong Thanh; Akay, Yasemin; Xu, Feng; Akay, Metin

    2016-01-01

    Glioblastoma multiforme (GBM) is the most common and malignant of all human primary brain cancers, in which drug treatment is still one of the most effective treatments. However, existing drug discovery and development methods rely on the use of conventional two-dimensional (2D) cell cultures, which have been proven to be poor representatives of native physiology. Here, we developed a novel three-dimensional (3D) brain cancer chip composed of photo-polymerizable poly(ethylene) glycol diacrylate (PEGDA) hydrogel for drug screening. This chip can be produced after a few seconds of photolithography and requires no silicon wafer, replica molding, and plasma bonding like microfluidic devices made of poly(dimethylsiloxane) (PDMS). We then cultured glioblastoma cells (U87), which formed 3D brain cancer tissues on the chip, and used the GBM chip to perform combinatorial treatment of Pitavastatin and Irinotecan. The results indicate that this chip is capable of high-throughput GBM cancer spheroids formation, multiple-simultaneous drug administration, and a massive parallel testing of drug response. Our approach is easily reproducible, and this chip has the potential to be a powerful platform in cases such as high-throughput drug screening and prolonged drug release. The chip is also commercially promising for other clinical applications, including 3D cell culture and micro-scale tissue engineering. PMID:27151082

  12. A multilayer microdevice for cell-based high-throughput drug screening

    NASA Astrophysics Data System (ADS)

    Liu, Chong; Wang, Lei; Xu, Zheng; Li, Jingmin; Ding, Xiping; Wang, Qi; Chunyu, Li

    2012-06-01

    A multilayer polydimethylsiloxane microdevice for cell-based high-throughput drug screening is described in this paper. This established microdevice was based on a modularization method and it integrated a drug/medium concentration gradient generator (CGG), pneumatic microvalves and a cell culture microchamber array. The CGG was able to generate five steps of linear concentrations with the same outlet flow rate. The medium/drug flowed through CGG and then into the pear-shaped cell culture microchambers vertically. This vertical perfusion mode was used to reduce the impact of the shear stress on the physiology of cells induced by the fluid flow in the microchambers. Pear-shaped microchambers with two arrays of miropillars at each outlet were adopted in this microdevice, which were beneficial to cell distribution. The chemotherapeutics Cisplatin (DDP)-induced Cisplatin-resistant cell line A549/DDP apoptotic experiments were performed well on this platform. The results showed that this novel microdevice could not only provide well-defined and stable conditions for cell culture, but was also useful for cell-based high-throughput drug screening with less reagents and time consumption.

  13. Protein traffic disorders: an effective high-throughput fluorescence microscopy pipeline for drug discovery.

    PubMed

    Botelho, Hugo M; Uliyakina, Inna; Awatade, Nikhil T; Proença, Maria C; Tischer, Christian; Sirianant, Lalida; Kunzelmann, Karl; Pepperkok, Rainer; Amaral, Margarida D

    2015-01-01

    Plasma membrane proteins are essential molecules in the cell which mediate interactions with the exterior milieu, thus representing key drug targets for present pharma. Not surprisingly, protein traffic disorders include a large range of diseases sharing the common mechanism of failure in the respective protein to reach the plasma membrane. However, specific therapies for these diseases are remarkably lacking. Herein, we report a robust platform for drug discovery applied to a paradigmatic genetic disorder affecting intracellular trafficking - Cystic Fibrosis. This platform includes (i) two original respiratory epithelial cellular models incorporating an inducible double-tagged traffic reporter; (ii) a plasma membrane protein traffic assay for high-throughput microscopy screening; and (iii) open-source image analysis software to quantify plasma membrane protein traffic. By allowing direct scoring of compounds rescuing the basic traffic defect, this platform enables an effective drug development pipeline, which can be promptly adapted to any traffic disorder-associated protein and leverage therapy development efforts.

  14. Preclinical drug metabolism in the age of high-throughput screening: an industrial perspective.

    PubMed

    Rodrigues, A D

    1997-11-01

    With the advent of genomics, combinatorial paradigms and high-throughput screen (HTS)-based pharmacological testing, the number of compounds flowing through the discovery pipeline is likely to escalate. At the same time, with increased knowledge of the human drug-metabolizing enzymes and the availability of in vitro absorption-metabolism (AM) models, Preclinical Drug Metabolism is poised to meet the challenges of HTS. In order to be successful, however, a rational HTS strategy (vs. serendipitous HTS) has to be employed. Such a strategy is based on automation, validation and integration of in vitro AM models and database management (AVID). A generalized strategy for rational (AVID-based) HTS in Preclinical Drug Metabolism is described briefly.

  15. Moderate to high throughput in vitro binding kinetics for drug discovery.

    PubMed

    Zhang, Rumin; Barbieri, Christopher M; Garcia-Calvo, Margarita; Myers, Robert W; McLaren, David; Kavana, Michael

    2016-01-01

    This review provides a concise summary for state of the art, moderate to high throughput in vitro technologies being employed to study drug-target binding kinetics. These technologies cover a wide kinetic timescale spanning up to nine orders of magnitude from milliseconds to days. Automated stopped flow measures transient and (pre)steady state kinetics from milliseconds to seconds. For seconds to hours timescale kinetics we discuss surface plasmon resonance-based biosensor, global progress curve analysis for high throughput kinetic profiling of enzyme inhibitors and activators, and filtration plate-based radioligand or fluorescent binding assays for receptor binding kinetics. Jump dilution after pre-incubation is the preferred method for very slow kinetics lasting for days. The basic principles, best practices and simulated data for these technologies are described. Finally, the application of a universal label-free technology, liquid chromatography coupled tandem mass spectrometry (LC/MS/MS), is briefly reviewed. Select literature references are highlighted for in-depth understanding. A new reality is dawning wherein binding kinetics is an integral and routine part of mechanism of action elucidation and translational, quantitative pharmacology for drug discovery. PMID:27100706

  16. Moderate to high throughput in vitro binding kinetics for drug discovery.

    PubMed

    Zhang, Rumin; Barbieri, Christopher M; Garcia-Calvo, Margarita; Myers, Robert W; McLaren, David; Kavana, Michael

    2016-06-01

    This review provides a concise summary for state of the art, moderate to high throughput in vitro technologies being employed to study drug-target binding kinetics. These technologies cover a wide kinetic timescale spanning up to nine orders of magnitude from milliseconds to days. Automated stopped flow measures transient and (pre)steady state kinetics from milliseconds to seconds. For seconds to hours timescale kinetics we discuss surface plasmon resonance-based biosensor, global progress curve analysis for high throughput kinetic profiling of enzyme inhibitors and activators, and filtration plate-based radioligand or fluorescent binding assays for receptor binding kinetics. Jump dilution after pre-incubation is the preferred method for very slow kinetics lasting for days. The basic principles, best practices and simulated data for these technologies are described. Finally, the application of a universal label-free technology, liquid chromatography coupled tandem mass spectrometry (LC/MS/MS), is briefly reviewed. Select literature references are highlighted for in-depth understanding. A new reality is dawning wherein binding kinetics is an integral and routine part of mechanism of action elucidation and translational, quantitative pharmacology for drug discovery.

  17. High-throughput drug library screening identifies colchicine as a thyroid cancer inhibitor

    PubMed Central

    Zhang, Le; Yang, Zhaoying; Granieri, Letizia; Pasculescu, Adrian; Datti, Alessandro; Asa, Sylvia L.; Xu, Zheli; Ezzat, Shereen

    2016-01-01

    We employed a high-throughput drug library screening platform to identify novel agents affecting thyroid cancer cells. We used human thyroid cancer cell lines to screen a collection of approximately 5200 small molecules with biological and/or pharmacologial properties. Parallel primary screens yielded a number of hits differentially active between thyroid and melanoma cells. Amongst compounds specifically targeting thyroid cancer cells, colchicine emerged as an effective candidate. Colchicine inhibited cell growth which correlated with G2 cell cycle arrest and apoptosis. These effects were hampered through inhibition of MEK1/2 and JNK. In contrast, inhibition of p38-MAPK had little effect, and AKT had no impact on colchicine action. Systemic colchicine inhibited thyroid cancer progression in xenografted mice. These findings demonstrate that our screening platform is an effective vehicle for drug reposition and show that colchicine warrants further attention in well-defined clinical niches such as thyroid cancer. PMID:26942566

  18. Drug-excipient compatibility testing using a high-throughput approach and statistical design.

    PubMed

    Wyttenbach, Nicole; Birringer, Christian; Alsenz, Jochem; Kuentz, Martin

    2005-01-01

    The aim of our research was to develop a miniaturized high throughput drug-excipient compatibility test. Experiments were planned and evaluated using statistical experimental design. Binary mixtures of a drug, acetylsalicylic acid, or fluoxetine hydrochloride, and of excipients commonly used in solid dosage forms were prepared at a ratio of approximately 1:100 in 96-well microtiter plates. Samples were exposed to different temperature (40 degrees C/ 50 degrees C) and humidity (10%/75%) for different time (1 week/4 weeks), and chemical drug degradation was analyzed using a fast gradient high pressure liquid chromatography (HPLC). Categorical statistical design was applied to identify the effects and interactions of time, temperature, humidity, and excipient on drug degradation. Acetylsalicylic acid was least stable in the presence of magnesium stearate, dibasic calcium phosphate, or sodium starch glycolate. Fluoxetine hydrochloride exhibited a marked degradation only with lactose. Factor-interaction plots revealed that the relative humidity had the strongest effect on the drug excipient blends tested. In conclusion, the developed technique enables fast drug-excipient compatibility testing and identification of interactions. Since only 0.1 mg of drug is needed per data point, fast rational preselection of the pharmaceutical additives can be performed early in solid dosage form development.

  19. Solid electrodes in electroanalytical chemistry: present applications and prospects for high throughput screening of drug compounds.

    PubMed

    Uslu, Bengi; Ozkan, Sibel A

    2007-08-01

    This review summarizes recent progress in the development and application of solid electrodes to the screening of pharmaceutical dosage forms and biological fluids. Recent trends and advances in the electroanalytical chemistry of solid electrodes, microelectrodes and electrochemical sensors are reviewed. The varieties of solid electrodes and their basic physico-chemical properties and some specific characteristics including some supramolecular phenomena at their surface are surveyed. This review also includes some selected designs and their applications. Despite many reviews about individual solid electrodes in the literature, this review offers the first comprehensive report on all forms of solid electrodes. Special attention is paid to the possibilities of solid electrodes in high throughput electroanalytical investigation of drug dosage forms and biological samples using modern electroanalytical techniques. Various selected studies on these subjects since 1996 are reviewed in this paper.

  20. Novel Phenotypic Fluorescent Three-Dimensional Platforms for High-throughput Drug Screening and Personalized Chemotherapy.

    PubMed

    Fang, Changge; Avis, Ingalill; Salomon, David; Cuttitta, Frank

    2013-01-01

    We have developed novel phenotypic fluorescent three-dimensional co-culture platforms that efficiently and economically screen anti-angiogenic/anti-metastatic drugs on a high-throughput scale. Individual cell populations can be identified and isolated for protein/gene expression profiling studies and cellular movement/interactions can be tracked by time-lapse cinematography. More importantly, these platforms closely parallel the in vivo angiogenic and metastatic outcomes of a given tumor xenograft in the nude mouse model but, unlike in vivo models, our co-culture platforms produce comparable results in five to nine days. Potentially, by incorporating cancer patient biopsies, the co-culture platforms should greatly improve the effectiveness and efficiency of personalized chemotherapy. PMID:23833685

  1. Corifungin, a new drug lead against Naegleria, identified from a high-throughput screen.

    PubMed

    Debnath, Anjan; Tunac, Josefino B; Galindo-Gómez, Silvia; Silva-Olivares, Angélica; Shibayama, Mineko; McKerrow, James H

    2012-11-01

    Primary amebic meningoencephalitis (PAM) is a rapidly fatal infection caused by the free-living ameba Naegleria fowleri. The drug of choice in treating PAM is the antifungal antibiotic amphotericin B, but its use is associated with severe adverse effects. Moreover, few patients treated with amphotericin B have survived PAM. Therefore, fast-acting and efficient drugs are urgently needed for the treatment of PAM. To facilitate drug screening for this pathogen, an automated, high-throughput screening methodology was developed and validated for the closely related species Naegleria gruberi. Five kinase inhibitors and an NF-kappaB inhibitor were hits identified in primary screens of three compound libraries. Most importantly for a preclinical drug discovery pipeline, we identified corifungin, a water-soluble polyene macrolide with a higher activity against Naegleria than that of amphotericin B. Transmission electron microscopy of N. fowleri trophozoites incubated with different concentrations of corifungin showed disruption of cytoplasmic and plasma membranes and alterations in mitochondria, followed by complete lysis of amebae. In vivo efficacy of corifungin in a mouse model of PAM was confirmed by an absence of detectable amebae in the brain and 100% survival of mice for 17 days postinfection for a single daily intraperitoneal dose of 9 mg/kg of body weight given for 10 days. The same dose of amphotericin B did not reduce ameba growth, and mouse survival was compromised. Based on these results, the U.S. FDA has approved orphan drug status for corifungin for the treatment of PAM. PMID:22869574

  2. Quantitative high-throughput identification of drugs as modulators of human constitutive androstane receptor.

    PubMed

    Lynch, Caitlin; Zhao, Jinghua; Huang, Ruili; Xiao, Jingwei; Li, Linhao; Heyward, Scott; Xia, Menghang; Wang, Hongbing

    2015-05-20

    The constitutive androstane receptor (CAR, NR1I3) plays a key role in governing the transcription of numerous hepatic genes that involve xenobiotic metabolism/clearance, energy homeostasis, and cell proliferation. Thus, identification of novel human CAR (hCAR) modulators may not only enhance early prediction of drug-drug interactions but also offer potentially novel therapeutics for diseases such as metabolic disorders and cancer. In this study, we have generated a double stable cell line expressing both hCAR and a CYP2B6-driven luciferase reporter for quantitative high-throughput screening (qHTS) of hCAR modulators. Approximately 2800 compounds from the NIH Chemical Genomics Center Pharmaceutical Collection were screened employing both the activation and deactivation modes of the qHTS. Activators (115) and deactivators (152) of hCAR were identified from the primary qHTS, among which 10 agonists and 10 antagonists were further validated in the physiologically relevant human primary hepatocytes for compound-mediated hCAR nuclear translocation and target gene expression. Collectively, our results reveal that hCAR modulators can be efficiently identified through this newly established qHTS assay. Profiling drug collections for hCAR activity would facilitate the prediction of metabolism-based drug-drug interactions, and may lead to the identification of potential novel therapeutics.

  3. Corifungin, a new drug lead against Naegleria, identified from a high-throughput screen.

    PubMed

    Debnath, Anjan; Tunac, Josefino B; Galindo-Gómez, Silvia; Silva-Olivares, Angélica; Shibayama, Mineko; McKerrow, James H

    2012-11-01

    Primary amebic meningoencephalitis (PAM) is a rapidly fatal infection caused by the free-living ameba Naegleria fowleri. The drug of choice in treating PAM is the antifungal antibiotic amphotericin B, but its use is associated with severe adverse effects. Moreover, few patients treated with amphotericin B have survived PAM. Therefore, fast-acting and efficient drugs are urgently needed for the treatment of PAM. To facilitate drug screening for this pathogen, an automated, high-throughput screening methodology was developed and validated for the closely related species Naegleria gruberi. Five kinase inhibitors and an NF-kappaB inhibitor were hits identified in primary screens of three compound libraries. Most importantly for a preclinical drug discovery pipeline, we identified corifungin, a water-soluble polyene macrolide with a higher activity against Naegleria than that of amphotericin B. Transmission electron microscopy of N. fowleri trophozoites incubated with different concentrations of corifungin showed disruption of cytoplasmic and plasma membranes and alterations in mitochondria, followed by complete lysis of amebae. In vivo efficacy of corifungin in a mouse model of PAM was confirmed by an absence of detectable amebae in the brain and 100% survival of mice for 17 days postinfection for a single daily intraperitoneal dose of 9 mg/kg of body weight given for 10 days. The same dose of amphotericin B did not reduce ameba growth, and mouse survival was compromised. Based on these results, the U.S. FDA has approved orphan drug status for corifungin for the treatment of PAM.

  4. Quantitative High-Throughput Identification of Drugs as Modulators of Human Constitutive Androstane Receptor

    PubMed Central

    Lynch, Caitlin; Zhao, Jinghua; Huang, Ruili; Xiao, Jingwei; Li, Linhao; Heyward, Scott; Xia, Menghang; Wang, Hongbing

    2015-01-01

    The constitutive androstane receptor (CAR, NR1I3) plays a key role in governing the transcription of numerous hepatic genes that involve xenobiotic metabolism/clearance, energy homeostasis, and cell proliferation. Thus, identification of novel human CAR (hCAR) modulators may not only enhance early prediction of drug-drug interactions but also offer potentially novel therapeutics for diseases such as metabolic disorders and cancer. In this study, we have generated a double stable cell line expressing both hCAR and a CYP2B6-driven luciferase reporter for quantitative high-throughput screening (qHTS) of hCAR modulators. Approximately 2800 compounds from the NIH Chemical Genomics Center Pharmaceutical Collection were screened employing both the activation and deactivation modes of the qHTS. Activators (115) and deactivators (152) of hCAR were identified from the primary qHTS, among which 10 agonists and 10 antagonists were further validated in the physiologically relevant human primary hepatocytes for compound-mediated hCAR nuclear translocation and target gene expression. Collectively, our results reveal that hCAR modulators can be efficiently identified through this newly established qHTS assay. Profiling drug collections for hCAR activity would facilitate the prediction of metabolism-based drug-drug interactions, and may lead to the identification of potential novel therapeutics. PMID:25993555

  5. Corifungin, a New Drug Lead against Naegleria, Identified from a High-Throughput Screen

    PubMed Central

    Debnath, Anjan; Tunac, Josefino B.; Galindo-Gómez, Silvia; Silva-Olivares, Angélica; Shibayama, Mineko

    2012-01-01

    Primary amebic meningoencephalitis (PAM) is a rapidly fatal infection caused by the free-living ameba Naegleria fowleri. The drug of choice in treating PAM is the antifungal antibiotic amphotericin B, but its use is associated with severe adverse effects. Moreover, few patients treated with amphotericin B have survived PAM. Therefore, fast-acting and efficient drugs are urgently needed for the treatment of PAM. To facilitate drug screening for this pathogen, an automated, high-throughput screening methodology was developed and validated for the closely related species Naegleria gruberi. Five kinase inhibitors and an NF-kappaB inhibitor were hits identified in primary screens of three compound libraries. Most importantly for a preclinical drug discovery pipeline, we identified corifungin, a water-soluble polyene macrolide with a higher activity against Naegleria than that of amphotericin B. Transmission electron microscopy of N. fowleri trophozoites incubated with different concentrations of corifungin showed disruption of cytoplasmic and plasma membranes and alterations in mitochondria, followed by complete lysis of amebae. In vivo efficacy of corifungin in a mouse model of PAM was confirmed by an absence of detectable amebae in the brain and 100% survival of mice for 17 days postinfection for a single daily intraperitoneal dose of 9 mg/kg of body weight given for 10 days. The same dose of amphotericin B did not reduce ameba growth, and mouse survival was compromised. Based on these results, the U.S. FDA has approved orphan drug status for corifungin for the treatment of PAM. PMID:22869574

  6. Open access high throughput drug discovery in the public domain: a Mount Everest in the making.

    PubMed

    Roy, Anuradha; McDonald, Peter R; Sittampalam, Sitta; Chaguturu, Rathnam

    2010-11-01

    High throughput screening (HTS) facilitates screening large numbers of compounds against a biochemical target of interest using validated biological or biophysical assays. In recent years, a significant number of drugs in clinical trails originated from HTS campaigns, validating HTS as a bona fide mechanism for hit finding. In the current drug discovery landscape, the pharmaceutical industry is embracing open innovation strategies with academia to maximize their research capabilities and to feed their drug discovery pipeline. The goals of academic research have therefore expanded from target identification and validation to probe discovery, chemical genomics, and compound library screening. This trend is reflected in the emergence of HTS centers in the public domain over the past decade, ranging in size from modestly equipped academic screening centers to well endowed Molecular Libraries Probe Centers Network (MLPCN) centers funded by the NIH Roadmap initiative. These centers facilitate a comprehensive approach to probe discovery in academia and utilize both classical and cutting-edge assay technologies for executing primary and secondary screening campaigns. The various facets of academic HTS centers as well as their implications on technology transfer and drug discovery are discussed, and a roadmap for successful drug discovery in the public domain is presented. New lead discovery against therapeutic targets, especially those involving the rare and neglected diseases, is indeed a Mount Everestonian size task, and requires diligent implementation of pharmaceutical industry's best practices for a successful outcome.

  7. High-throughput screening with nanoimprinting 3D culture for efficient drug development by mimicking the tumor environment.

    PubMed

    Yoshii, Yukie; Furukawa, Takako; Waki, Atsuo; Okuyama, Hiroaki; Inoue, Masahiro; Itoh, Manabu; Zhang, Ming-Rong; Wakizaka, Hidekatsu; Sogawa, Chizuru; Kiyono, Yasushi; Yoshii, Hiroshi; Fujibayashi, Yasuhisa; Saga, Tsuneo

    2015-05-01

    Anti-cancer drug development typically utilizes high-throughput screening with two-dimensional (2D) cell culture. However, 2D culture induces cellular characteristics different from tumors in vivo, resulting in inefficient drug development. Here, we report an innovative high-throughput screening system using nanoimprinting 3D culture to simulate in vivo conditions, thereby facilitating efficient drug development. We demonstrated that cell line-based nanoimprinting 3D screening can more efficiently select drugs that effectively inhibit cancer growth in vivo as compared to 2D culture. Metabolic responses after treatment were assessed using positron emission tomography (PET) probes, and revealed similar characteristics between the 3D spheroids and in vivo tumors. Further, we developed an advanced method to adopt cancer cells from patient tumor tissues for high-throughput drug screening with nanoimprinting 3D culture, which we termed Cancer tissue-Originated Uniformed Spheroid Assay (COUSA). This system identified drugs that were effective in xenografts of the original patient tumors. Nanoimprinting 3D spheroids showed low permeability and formation of hypoxic regions inside, similar to in vivo tumors. Collectively, the nanoimprinting 3D culture provides easy-handling high-throughput drug screening system, which allows for efficient drug development by mimicking the tumor environment. The COUSA system could be a useful platform for drug development with patient cancer cells.

  8. CRIMALDDI: a prioritized research agenda to expedite the discovery of new anti-malarial drugs

    PubMed Central

    2013-01-01

    The CRIMALDDI Consortium has been a three-year project funded by the EU Framework Seven Programme. It aimed to develop a prioritized set of recommendations to speed up anti-malarial drug discovery research and contribute to the setting of the global research agenda. It has attempted to align thinking on the high priority issues and then to develop action plans and strategies to address these issues. Through a series of facilitated and interactive workshops, it has concluded that these priorities can be grouped under five key themes: attacking artemisinin resistance; creating and sharing community resources; delivering enabling technologies; exploiting high throughput screening hits quickly; and, identifying novel targets. Recommendations have been prioritized into one of four levels: quick wins; removing key roadblocks to future progress; speeding-up drug discovery; and, nice to have (but not essential). Use of this prioritization allows efforts and resources to be focused on the lines of work that will contribute most to expediting anti-malarial drug discovery. Estimates of the time and finances required to implement the recommendations have also been made, along with indications of when recommendations within each theme will make an impact. All of this has been collected into an indicative roadmap that, it is hoped, will guide decisions about the direction and focus of European anti-malarial drug discovery research and contribute to the setting of the global research agenda. PMID:24191947

  9. Microengineering Methods for Cell Based Microarrays and High-Throughput Drug Screening Applications

    PubMed Central

    Xu, Feng; Wu, JinHui; Wang, ShuQi; Durmus, Naside Gozde; Gurkan, Umut Atakan; Demirci, Utkan

    2011-01-01

    Screening for effective therapeutic agents from millions of drug candidates is costly, time-consuming and often face ethical concerns due to extensive use of animals. To improve cost-effectiveness, and to minimize animal testing in pharmaceutical research, in vitro monolayer cell microarrays with multiwell plate assays have been developed. Integration of cell microarrays with microfluidic systems have facilitated automated and controlled component loading, significantly reducing the consumption of the candidate compounds and the target cells. Even though these methods significantly increased the throughput compared to conventional in vitro testing systems and in vivo animal models, the cost associated with these platforms remains prohibitively high. Besides, there is a need for three-dimensional (3D) cell based drug-screening models, which can mimic the in vivo microenvironment and the functionality of the native tissues. Here, we present the state-of-the-art microengineering approaches that can be used to develop 3D cell based drug screening assays. We highlight the 3D in vitro cell culture systems with live cell-based arrays, microfluidic cell culture systems, and their application to high-throughput drug screening. We conclude that among the emerging microengineering approaches, bioprinting holds a great potential to provide repeatable 3D cell based constructs with high temporal, spatial control and versatility. PMID:21725152

  10. High-Throughput Screening for Drugs that Modulate Intermediate Filament Proteins.

    PubMed

    Sun, Jingyuan; Groppi, Vincent E; Gui, Honglian; Chen, Lu; Xie, Qing; Liu, Li; Omary, M Bishr

    2016-01-01

    Intermediate filament (IF) proteins have unique and complex cell and tissue distribution. Importantly, IF gene mutations cause or predispose to more than 80 human tissue-specific diseases (IF-pathies), with the most severe disease phenotypes being due to mutations at conserved residues that result in a disrupted IF network. A critical need for the entire IF-pathy field is the identification of drugs that can ameliorate or cure these diseases, particularly since all current therapies target the IF-pathy complication, such as diabetes or cardiovascular disease, rather than the mutant IF protein or gene. We describe a high-throughput approach to identify drugs that can normalize disrupted IF proteins. This approach utilizes transduction of lentivirus that expresses green fluorescent protein-tagged keratin 18 (K18) R90C in A549 cells. The readout is drug "hits" that convert the dot-like keratin filament distribution, due to the R90C mutation, to a wild-type-like filamentous array. A similar strategy can be used to screen thousands of compounds and can be utilized for practically any IF protein with a filament-disrupting mutation, and could therefore potentially target many IF-pathies. "Hits" of interest require validation in cell culture then using in vivo experimental models. Approaches to study the mechanism of mutant IF normalization by potential drugs of interest are also described. The ultimate goal of this drug screening approach is to identify effective and safe compounds that can potentially be tested for clinical efficacy in patients.

  11. High-Throughput Phase-Distribution Method to Determine Drug-Cyclodextrin Binding Constants

    PubMed Central

    CHEN, ZHI; LU, DUJUAN; WEBER, STEPHEN G.

    2009-01-01

    A high-throughput method has been developed to measure drug-cyclodextrin binding constants. It measures the distribution ratio of a drug between a polymer film [polyvinyl chloride (PVC) with 67% (w/w) dioctyl sebacate (DOS)] and a cyclodextrin-containing buffer in a 96-well format. Measurements of distribution ratios at several cyclodextrin concentrations lead to binding constants. Binding constants for econazole with six CDs have been determined in one 96-well microplate with four replications of each condition in 10 h. The K1:1/103 M−1 values are 3.98±0.13, 3.90±0.22, 29.3±2.2, 0.66±0.04 1.78±0.30, 4.08±0.50, with (2-hydroxyethyl)-β-cyclodextrin, (2-hydroxypropyl)-β-cyclodextrin, 2,6-di-O-methyl-β-cyclodextrin, hepta-kis(2,3,6-tri-O-methyl)-β-cyclodextrin, α-cyclodextrin, β-cyclodextrin, respectively. It is likely that 1:2 complexes are also formed in some cases. This method has also been applied to study the binding behavior as a function of the drug concentration and pH. Binding weakens at higher drug concentration which may be due to the self-association of the drug. An acidic environment decreases the binding constant of CD with the basic econazole. The formation of the 1:2 complexes is completely suppressed in acid as well. This protocol is faster than the phase-solubility method. Moreover, the material requirement is up to four orders of magnitude lower. PMID:18428984

  12. Drug Discovery and Development of Antimalarial Agents: Recent Advances.

    PubMed

    Thota, Sreekanth; Yerra, Rajeshwar

    2016-01-01

    Malaria, a deadly infectious parasitic disease, is a major issue of public health in the world today and already produces serious economic constraints in the endemic countries. Most of the malarial infections and deaths are due to Plasmodium falciparum and Plasmodium vivax species. The recent emergence of resistance necessitates the search for new antimalarial drugs, which overcome the resistance and act through new mechanisms. Although much effort has been directed towards the discovery of novel antimalarial drugs. 4-anilino quinolone triazines as potent antimalarial agents, their in silico modelling and bioevaluation as Plasmodium falciparum transketolase and β-hematin inhibitors has been reported. This review is primarily focused on the drug discovery of the recent advances in the development of antimalarial agents and their mechanism of action.

  13. High-throughput mapping of brain-wide activity in awake and drug-responsive vertebrates.

    PubMed

    Lin, Xudong; Wang, Shiqi; Yu, Xudong; Liu, Zhuguo; Wang, Fei; Li, Wai Tsun; Cheng, Shuk Han; Dai, Qiuyun; Shi, Peng

    2015-02-01

    The reconstruction of neural activity across complete neural circuits, or brain activity mapping, has great potential in both fundamental and translational neuroscience research. Larval zebrafish, a vertebrate model, has recently been demonstrated to be amenable to whole brain activity mapping in behaving animals. Here we demonstrate a microfluidic array system ("Fish-Trap") that enables high-throughput mapping of brain-wide activity in awake larval zebrafish. Unlike the commonly practiced larva-processing methods using a rigid gel or a capillary tube, which are laborious and time-consuming, the hydrodynamic design of our microfluidic chip allows automatic, gel-free, and anesthetic-free processing of tens of larvae for microscopic imaging with single-cell resolution. Notably, this system provides the capability to directly couple pharmaceutical stimuli with real-time recording of neural activity in a large number of animals, and the local and global effects of pharmacoactive drugs on the nervous system can be directly visualized and evaluated by analyzing drug-induced functional perturbation within or across different brain regions. Using this technology, we tested a set of neurotoxin peptides and obtained new insights into how to exploit neurotoxin derivatives as therapeutic agents. The novel and versatile "Fish-Trap" technology can be readily unitized to study other stimulus (optical, acoustic, or physical) associated functional brain circuits using similar experimental strategies.

  14. Anti-malarial Drug Design by Targeting Apicoplasts: New Perspectives

    PubMed Central

    Mukherjee, Avinaba; Sadhukhan, Gobinda Chandra

    2016-01-01

    Objectives: Malaria has been a major global health problem in recent times with increasing mortality. Current treatment methods include parasiticidal drugs and vaccinations. However, resistance among malarial parasites to the existing drugs has emerged as a significant area of concern in anti-malarial drug design. Researchers are now desperately looking for new targets to develop anti-malarials drug which is more target specific. Malarial parasites harbor a plastid-like organelle known as the ‘apicoplast’, which is thought to provide an exciting new outlook for the development of drugs to be used against the parasite. This review elaborates on the current state of development of novel compounds targeted againstemerging malaria parasites. Methods: The apicoplast, originates by an endosymbiotic process, contains a range of metabolic pathways and housekeeping processes that differ from the host body and thereby presents ideal strategies for anti-malarial drug therapy. Drugs are designed by targeting the unique mechanism of the apicoplasts genetic machinery. Several anabolic and catabolic processes, like fatty acid, isopenetyl diphosphate and heme synthess in this organelle, have also been targeted by drugs. Results: Apicoplasts offer exciting opportunities for the development of malarial treatment specific drugs have been found to act by disrupting this organelle’s function, which wouldimpede the survival of the parasite. Conclusion: Recent advanced drugs, their modes of action, and their advantages in the treatment of malaria by using apicoplasts as a target are discussed in this review which thought to be very useful in desigining anti-malarial drugs. Targetting the genetic machinery of apicoplast shows a great advantange regarding anti-malarial drug design. Critical knowledge of these new drugs would give a healthier understanding for deciphering the mechanism of action of anti-malarial drugs when targeting apicoplasts to overcome drug resistance. PMID

  15. Development of Drugs for Epstein - Barr virus using High-Throughput in silico Virtual Screening

    PubMed Central

    Li, Ning; Thompson, Scott; Jiang, Hualiang; Lieberman, Paul M.; Luo, Cheng

    2010-01-01

    Importance of the field Epstein-Barr virus (EBV) is a ubiquitious human herpesvirus that is causally associated with endemic forms of Burkitt’s lymphoma (BL), nasopharyngeal carcinoma, and lymphoproliferative disease in immunosuppressed individuals. On a global scale, EBV infects over 90% of the adult population and is responsible for ~1% of all human cancers. To date, there is no efficacious drug or therapy for the treatment of EBV infection and EBV-related diseases. Areas covered in this review In this review, we discuss the existing anti-EBV inhibitors and those under development. We discuss the value of different molecular targets, including EBV lytic DNA replication enzymes, as well as proteins that are expressed exclusively during latent infection, like EBNA1 and LMP1. Since the atomic structure of the EBNA1 DNA binding domain has been described, it is an attractive target for in silico methods of drug design and small molecule screening. We discuss the use of computational methods that can greatly facilitate the development of novel inhibitors and how in silico screening methods can be applied to target proteins with known structures, like EBNA1, to treat EBV infection and disease. What the reader will gain The reader will be familiarized with the problems in targeting of EBV for inhibition by small molecules and how computational methods can greatly facilitate this process. Take home message Despite the impressive efficacy of nucleoside analogues for the treatment of herpesvirus lytic infection, there remain few effective treatments for latent infections. Since EBV-latent infection persists within and contributes to the formation of EBV-associated cancers, targeting EBV latent proteins is an unmet medical need. High throughput in silico screening can accelerate the process of drug discovery for novel and selective agents that inhibit EBV latent infection and associated disease. PMID:22822721

  16. Fluorescence polarization assays in high-throughput screening and drug discovery: a review

    NASA Astrophysics Data System (ADS)

    Hall, Matthew D.; Yasgar, Adam; Peryea, Tyler; Braisted, John C.; Jadhav, Ajit; Simeonov, Anton; Coussens, Nathan P.

    2016-06-01

    The sensitivity of fluorescence polarization (FP) and fluorescence anisotropy (FA) to molecular weight changes has enabled the interrogation of diverse biological mechanisms, ranging from molecular interactions to enzymatic activity. Assays based on FP/FA technology have been widely utilized in high-throughput screening (HTS) and drug discovery due to the homogenous format, robust performance and relative insensitivity to some types of interferences, such as inner filter effects. Advancements in assay design, fluorescent probes, and technology have enabled the application of FP assays to increasingly complex biological processes. Herein we discuss different types of FP/FA assays developed for HTS, with examples to emphasize the diversity of applicable targets. Furthermore, trends in target and fluorophore selection, as well as assay type and format, are examined using annotated HTS assays within the PubChem database. Finally, practical considerations for the successful development and implementation of FP/FA assays for HTS are provided based on experience at our center and examples from the literature, including strategies for flagging interference compounds among a list of hits.

  17. Assay development and high throughput antiviral drug screening against Bluetongue virus

    PubMed Central

    Li, Qianjun; Maddox, Clinton; Rasmussen, Lynn; Hobrath, Judith V.; White, Lucile E.

    2009-01-01

    Bluetongue virus (BTV) infection is one of the most important diseases of domestic livestock. There are no antivirals available against BTV disease. In this paper, we present the development, optimization and validation of an in vitro cell-based high-throughput screening (HTS) assay using the luminescent-based CellTiter-Glo reagent to identify novel antivirals against BTV. Conditions of the cytopathic effect (CPE)-based assay were optimized at cell density of 5 000 cells/well in medium containing 1% FBS and a multiplicity of infection at 0.01 in 384-well plate, with Z'-values ≥ 0.70, Coefficient of Variations ≥ 5.68 and signal-to-background ratio ≥ 7.10. This assay was further validated using a 9 532 compound library. The fully validated assay was then used to screen the 194 950 compound collection, which identified 693 compounds with > 30% CPE inhibition. The ten-concentration dose response assay identified 185 structures with IC50 ≤ 100 μM, out of which 42 compounds were grouped into six analog series corresponding to six scaffolds enriched within the active set compared to their distribution in the library. The CPE-based assay development demonstrated its robustness and reliability, and its application in the HTS campaign will make significant contribution to the antiviral drug discovery against BTV disease. PMID:19559054

  18. Alternative to the soft-agar assay that permits high-throughput drug and genetic screens for cellular transformation

    PubMed Central

    Rotem, Asaf; Janzer, Andreas; Izar, Benjamin; Ji, Zhe; Doench, John G.; Garraway, Levi A.; Struhl, Kevin

    2015-01-01

    Colony formation in soft agar is the gold-standard assay for cellular transformation in vitro, but it is unsuited for high-throughput screening. Here, we describe an assay for cellular transformation that involves growth in low attachment (GILA) conditions and is strongly correlated with the soft-agar assay. Using GILA, we describe high-throughput screens for drugs and genes that selectively inhibit or increase transformation, but not proliferation. Such molecules are unlikely to be found through conventional drug screening, and they include kinase inhibitors and drugs for noncancer diseases. In addition to known oncogenes, the genetic screen identifies genes that contribute to cellular transformation. Lastly, we demonstrate the ability of Food and Drug Administration-approved noncancer drugs to selectively kill ovarian cancer cells derived from patients with chemotherapy-resistant disease, suggesting this approach may provide useful information for personalized cancer treatment. PMID:25902495

  19. Ecotoxicological evaluation of the antimalarial drug chloroquine.

    PubMed

    Zurita, Jorge L; Jos, Angeles; del Peso, Ana; Salguero, Manuel; López-Artíguez, Miguel; Repetto, Guillermo

    2005-10-15

    There is limited information available about the potential environmental effects of chloroquine (CQ), a widely used antimalarial agent and a promising inexpensive drug in the management of HIV disease. The acute effects of CQ were studied using four ecotoxicological model systems. The most sensitive bioindicator was the immobilization of the cladoceran Daphnia magna, with an EC50 of 12 microM CQ at 72 h and a non-observed adverse effect level of 2.5 microM CQ, followed very closely by the decrease of the uptake of neutral red and the reduction of the lysosomal function in the fish cell line PLHC-1 derived from the top minnow Poeciliopsis lucida, probably due to the selective accumulation of the drug into the lysosomes. There was significant cellular stress as indicated by the increases on metallothionein and glucose-6P dehydrogenase levels after 24 h of exposure and succinate dehydrogenase activity mainly after 48 h. No changes were observed for ethoxyresorufin-O-deethylase (EROD) activity. The least sensitive model was the inhibition of bioluminescence in the bacterium Vibrio fischeri. An increase of more than five-fold in the toxicity from 24 to 72 h of exposure was observed for the inhibition of the growth in the alga Chlorella vulgaris and the content of total protein and MTS tetrazolium salt metabolization in PLHC-1 cells. At the morphological level, the most evident alterations in PLHC-1 cultures were hydropic degeneration from 25 microM CQ after 24h of exposure and the presence of many cells with pyknotic nuclei, condensed cytoplasm and apoptosis with concentrations higher than 50 microM CQ after 48 h of exposure. In conclusion, CQ should be classified as harmful to aquatic organisms. PMID:16153718

  20. Antimalarial drug policy in India: Past, present & future

    PubMed Central

    Anvikar, Anupkumar R.; Arora, Usha; Sonal, G.S.; Mishra, Neelima; Shahi, Bharatendu; Savargaonkar, Deepali; Kumar, Navin; Shah, Naman K.; Valecha, Neena

    2014-01-01

    The use of antimalarial drugs in India has evolved since the introduction of quinine in the 17th century. Since the formal establishment of a malaria control programme in 1953, shortly after independence, treatments provided by the public sector ranged from chloroquine, the mainstay drug for many decades, to the newer, recently introduced artemisinin based combination therapy. The complexity of considerations in antimalarial treatment led to the formulation of a National Antimalarial Drug Policy to guide procurement as well as communicate best practices to both public and private healthcare providers. Challenges addressed in the policy include the use of presumptive treatment, the introduction of alternate treatments for drug-resistant malaria, the duration of primaquine therapy to prevent relapses of vivax malaria, the treatment of malaria in pregnancy, and the choice of drugs for chemoprophylaxis. While data on antimalarial drug resistance and both public and private sector treatment practices have been recently reviewed, the policy process of setting national standards has not. In this perspective on antimalarial drug policy, this review highlights its relevant history, analyzes the current policy, and examines future directions. PMID:24718394

  1. Novel drug candidates for blast phase chronic myeloid leukemia from high-throughput drug sensitivity and resistance testing

    PubMed Central

    Pietarinen, P O; Pemovska, T; Kontro, M; Yadav, B; Mpindi, J P; Andersson, E I; Majumder, M M; Kuusanmäki, H; Koskenvesa, P; Kallioniemi, O; Wennerberg, K; Heckman, C A; Mustjoki, S; Porkka, K

    2015-01-01

    Chronic myeloid leukemia in blast crisis (CML BC) remains a challenging disease to treat despite the introduction and advances in tyrosine kinase inhibitor (TKI) therapy. In this study we set out to identify novel candidate drugs for CML BC by using an unbiased high-throughput drug testing platform. We used three CML cell lines representing different types of CML blast phases (K562, EM-2 and MOLM-1) and primary leukemic cells from three CML BC patients. Profiling of drug responses was performed with a drug sensitivity and resistance testing platform comprising 295 anticancer agents. Overall, drug sensitivity scores and the drug response profiles of cell line and primary cell samples correlated well and were distinct from other types of leukemia samples. The cell lines were highly sensitive to TKIs and the clinically TKI-resistant patient samples were also resistant ex vivo. Comparison of cell line and patient sample data identified new candidate drugs for CML BC, such as vascular endothelial growth factor receptor and nicotinamide phosphoribosyltransferase inhibitors. Our results indicate that these drugs in particular warrant further evaluation by analyzing a larger set of primary patient samples. The results also pave way for designing rational combination therapies. PMID:25933373

  2. Antimalarial Drug Discovery: From Quinine to the Dream of Eradication

    PubMed Central

    2013-01-01

    The search for antimalarial remedies predates modern medicine and the concept of small molecule chemotherapy, yet has played a central role in the development of both. This history is reviewed in the context of the current renaissance in antimalarial drug discovery, which is seeing modern drug discovery approaches applied to the problem for the first time. Great strides have been made in the past decade, but further innovations from the drug discovery community will be required if the ultimate dream of eradication is to be achieved. PMID:24790706

  3. Identification of new drug candidates against Borrelia burgdorferi using high-throughput screening.

    PubMed

    Pothineni, Venkata Raveendra; Wagh, Dhananjay; Babar, Mustafeez Mujtaba; Inayathullah, Mohammed; Solow-Cordero, David; Kim, Kwang-Min; Samineni, Aneesh V; Parekh, Mansi B; Tayebi, Lobat; Rajadas, Jayakumar

    2016-01-01

    Lyme disease is the most common zoonotic bacterial disease in North America. It is estimated that >300,000 cases per annum are reported in USA alone. A total of 10%-20% of patients who have been treated with antibiotic therapy report the recrudescence of symptoms, such as muscle and joint pain, psychosocial and cognitive difficulties, and generalized fatigue. This condition is referred to as posttreatment Lyme disease syndrome. While there is no evidence for the presence of viable infectious organisms in individuals with posttreatment Lyme disease syndrome, some researchers found surviving Borrelia burgdorferi population in rodents and primates even after antibiotic treatment. Although such observations need more ratification, there is unmet need for developing the therapeutic agents that focus on removing the persisting bacterial form of B. burgdorferi in rodent and nonhuman primates. For this purpose, high-throughput screening was done using BacTiter-Glo assay for four compound libraries to identify candidates that stop the growth of B. burgdorferi in vitro. The four chemical libraries containing 4,366 compounds (80% Food and Drug Administration [FDA] approved) that were screened are Library of Pharmacologically Active Compounds (LOPAC1280), the National Institutes of Health Clinical Collection, the Microsource Spectrum, and the Biomol FDA. We subsequently identified 150 unique compounds, which inhibited >90% of B. burgdorferi growth at a concentration of <25 µM. These 150 unique compounds comprise many safe antibiotics, chemical compounds, and also small molecules from plant sources. Of the 150 unique compounds, 101 compounds are FDA approved. We selected the top 20 FDA-approved molecules based on safety and potency and studied their minimum inhibitory concentration and minimum bactericidal concentration. The promising safe FDA-approved candidates that show low minimum inhibitory concentration and minimum bactericidal concentration values can be chosen as lead

  4. Identification of new drug candidates against Borrelia burgdorferi using high-throughput screening

    PubMed Central

    Pothineni, Venkata Raveendra; Wagh, Dhananjay; Babar, Mustafeez Mujtaba; Inayathullah, Mohammed; Solow-Cordero, David; Kim, Kwang-Min; Samineni, Aneesh V; Parekh, Mansi B; Tayebi, Lobat; Rajadas, Jayakumar

    2016-01-01

    Lyme disease is the most common zoonotic bacterial disease in North America. It is estimated that >300,000 cases per annum are reported in USA alone. A total of 10%–20% of patients who have been treated with antibiotic therapy report the recrudescence of symptoms, such as muscle and joint pain, psychosocial and cognitive difficulties, and generalized fatigue. This condition is referred to as posttreatment Lyme disease syndrome. While there is no evidence for the presence of viable infectious organisms in individuals with posttreatment Lyme disease syndrome, some researchers found surviving Borrelia burgdorferi population in rodents and primates even after antibiotic treatment. Although such observations need more ratification, there is unmet need for developing the therapeutic agents that focus on removing the persisting bacterial form of B. burgdorferi in rodent and nonhuman primates. For this purpose, high-throughput screening was done using BacTiter-Glo assay for four compound libraries to identify candidates that stop the growth of B. burgdorferi in vitro. The four chemical libraries containing 4,366 compounds (80% Food and Drug Administration [FDA] approved) that were screened are Library of Pharmacologically Active Compounds (LOPAC1280), the National Institutes of Health Clinical Collection, the Microsource Spectrum, and the Biomol FDA. We subsequently identified 150 unique compounds, which inhibited >90% of B. burgdorferi growth at a concentration of <25 µM. These 150 unique compounds comprise many safe antibiotics, chemical compounds, and also small molecules from plant sources. Of the 150 unique compounds, 101 compounds are FDA approved. We selected the top 20 FDA-approved molecules based on safety and potency and studied their minimum inhibitory concentration and minimum bactericidal concentration. The promising safe FDA-approved candidates that show low minimum inhibitory concentration and minimum bactericidal concentration values can be chosen as

  5. Drug resistance genomics of the antimalarial drug artemisinin.

    PubMed

    Winzeler, Elizabeth A; Manary, Micah J

    2014-01-01

    Across the globe, over 200 million annual malaria infections result in up to 660,000 deaths, 77% of which occur in children under the age of five years. Although prevention is important, malaria deaths are typically prevented by using antimalarial drugs that eliminate symptoms and clear parasites from the blood. Artemisinins are one of the few remaining compound classes that can be used to cure multidrug-resistant Plasmodium falciparum infections. Unfortunately, clinical trials from Southeast Asia are showing that artemisinin-based treatments are beginning to lose their effectiveness, adding renewed urgency to the search for the genetic determinants of parasite resistance to this important drug class. We review the genetic and genomic approaches that have led to an improved understanding of artemisinin resistance, including the identification of resistance-conferring mutations in the P. falciparum kelch13 gene. PMID:25470531

  6. A high-throughput cell-based method to predict the unbound drug fraction in the brain.

    PubMed

    Mateus, André; Matsson, Pär; Artursson, Per

    2014-04-10

    Optimization of drug efficacy in the brain requires understanding of the local exposure to unbound drug at the site of action. This relies on measurements of the unbound drug fraction (fu,brain), which currently requires access to brain tissue. Here, we present a novel methodology using homogenates of cultured cells for rapid estimation of fu,brain. In our setup, drug binding to human embryonic kidney cell (HEK293) homogenate was measured in a small-scale dialysis apparatus. To increase throughput, we combined drugs into cassettes for simultaneous measurement of multiple compounds. Our method estimated fu,brain with an average error of 1.9-fold. We propose that our simple method can be used as an inexpensive, easily available and high-throughput alternative to brain tissues excised from laboratory animals. Thereby, estimates of unbound drug exposure can now be implemented at a much earlier stage of the drug discovery process, when molecular property changes are easier to make.

  7. High-throughput microsomal stability assay for screening new chemical entities in drug discovery.

    PubMed

    Fonsi, Massimiliano; Orsale, Maria V; Monteagudo, Edith

    2008-10-01

    In this work, the authors present a novel, robotic, automated protocol for assessing a metabolic stability protocol assembled on a Hamilton platform and a new strategy for pooling samples (cassette analysis). To increase the high throughput of the liquid chromatography (LC) step, fast chromatography and automated liquid chromatography tandem mass spectrometry (LC/MS/MS) analytical methods were also developed, and a rapid data analysis system was generated that converts peak areas obtained by LC/MS/MS in intrinsic clearance values. All of the steps of the microsomal stability assay were carefully studied and optimized. Standard errors and confidence intervals of the measured clearances were also automatically generated in the process to allow an immediate evaluation of the significance of observed values. Methods based on pooling analysis of 2 and 4 different analytes were compared with a standard method without pooling. A simple statistical treatment was used to show their equivalence. The different protocols developed were analyzed in terms of the best compromise between accuracy and high-throughput capabilities.

  8. Artemisinin anti-malarial drugs in China

    PubMed Central

    Guo, Zongru

    2016-01-01

    Discovered by Youyou Tu, one of the 2015 Nobel Prize winners in Physiology or Medicine, together with many other Chinese scientists, artemisinin, artemether and artesunate, as well as other artemisinins, have brought the global anti-malarial treatment to a new era, saving millions of lives all around the world for the past 40 years. The discoveries of artemisinins were carried out beginning from the 1970s, a special period in China, by hundreds of scientists all together under the “whole nation” system. This article focusing on medicinal chemistry research, briefly introduced the discovery and invention course of the scientists according to the published papers, and highlighted their academic contribution and achievements. PMID:27006895

  9. A Novel High Throughput Assay for Anthelmintic Drug Screening and Resistance Diagnosis by Real-Time Monitoring of Parasite Motility

    PubMed Central

    Smout, Michael J.; Kotze, Andrew C.; McCarthy, James S.; Loukas, Alex

    2010-01-01

    Background Helminth parasites cause untold morbidity and mortality to billions of people and livestock. Anthelmintic drugs are available but resistance is a problem in livestock parasites, and is a looming threat for human helminths. Testing the efficacy of available anthelmintic drugs and development of new drugs is hindered by the lack of objective high-throughput screening methods. Currently, drug effect is assessed by observing motility or development of parasites using laborious, subjective, low-throughput methods. Methodology/Principal Findings Here we describe a novel application for a real-time cell monitoring device (xCELLigence) that can simply and objectively assess anthelmintic effects by measuring parasite motility in real time in a fully automated high-throughput fashion. We quantitatively assessed motility and determined real time IC50 values of different anthelmintic drugs against several developmental stages of major helminth pathogens of humans and livestock, including larval Haemonchus contortus and Strongyloides ratti, and adult hookworms and blood flukes. The assay enabled quantification of the onset of egg hatching in real time, and the impact of drugs on hatch rate, as well as discriminating between the effects of drugs on motility of drug-susceptible and –resistant isolates of H. contortus. Conclusions/Significance Our findings indicate that this technique will be suitable for discovery and development of new anthelmintic drugs as well as for detection of phenotypic resistance to existing drugs for the majority of helminths and other pathogens where motility is a measure of pathogen viability. The method is also amenable to use for other purposes where motility is assessed, such as gene silencing or antibody-mediated killing. PMID:21103363

  10. Substandard anti-malarial drugs in Burkina Faso

    PubMed Central

    Tipke, Maike; Diallo, Salou; Coulibaly, Boubacar; Störzinger, Dominic; Hoppe-Tichy, Torsten; Sie, Ali; Müller, Olaf

    2008-01-01

    Background There is concern about an increasing infiltration of markets by substandard and fake medications against life-threatening diseases in developing countries. This is particularly worrying with regard to the increasing resistance development of Plasmodium falciparum against affordable anti-malarial medications, which has led to a change to more expensive drugs in most endemic countries. Methods A representative sample of modern anti-malarial medications from licensed (public and private pharmacies, community health workers) and illicit (market and street vendors, shops) sources has been collected in the Nouna Health District in north-western Burkina Faso in 2006. All drugs were tested for their quality with the standard procedures of the German Pharma Health Fund-Minilab. Detected low standard drugs were re-tested with European Pharmacopoeia 2.9.1 standards for disintegration and ultraviolet-visible spectroscopy at the laboratory of the Heidelberg University for confirmation. Results Overall, 86 anti-malarial drug samples were collected, of which 77 samples have been included in the final analysis. The sample consisted of 39/77 (50%) chloroquine, 10/77 (13%) pyrimethamine-sulphadoxine, 9/77 (12%) quinine, 6/77 (8%) amodiaquine, 9/77 (12%) artesunate, and 4/77 (5%) artemether-lumefantrine. 32/77 (42%) drug samples were found to be of poor quality, of which 28 samples failed the visual inspection, nine samples had substandard concentrations of the active ingredient, four samples showed poor disintegration, and one sample contained non of the stated active ingredient. The licensed and the illicit market contributed 5/47 (10.6%) and 27/30 (90.0%) samples of substandard drugs respectively. Conclusion These findings provide further evidence for the wide-spread existence of substandard anti-malarial medications in Africa and call for strengthening of the regulatory and quality control capacity of affected countries, particularly in view of the now wider available

  11. Facile and rapid generation of 3D chemical gradients within hydrogels for high-throughput drug screening applications.

    PubMed

    Ahadian, Samad; Ramón-Azcón, Javier; Estili, Mehdi; Obregón, Raquel; Shiku, Hitoshi; Matsue, Tomokazu

    2014-09-15

    We propose a novel application of dielectrophoresis (DEP) to make three-dimensional (3D) methacrylated gelatin (GelMA) hydrogels with gradients of micro- and nanoparticles. DEP forces were able to manipulate micro- and nanoparticles of different sizes and materials (i.e., C2C12 myoblasts, polystyrene beads, gold microparticles, and carbon nanotubes) within GelMA hydrogels in a rapid and facile way and create 3D gradients of these particles in a microchamber. Immobilization of drugs, such as fluorescein isothiocyanate-dextran (FITC-dextran) and 6-hydroxydopamine (6-OHDA), on gold microparticles allowed us to investigate the high-throughput release of these drugs from GelMA-gold microparticle gradient systems. The latter gradient constructs were incubated with C2C12 myoblasts for 24h to examine the cell viability through the release of 6-OHDA. The drug was released from the microparticles in a gradient manner, inducing a cell viability gradient. This novel approach to create 3D chemical gradients within hydrogels is scalable to any arbitrary length scale. It is useful for making anisotropic biomimetic materials and high-throughput platforms to investigate cell-microenvironment interactions in a rapid, simple, cost-effective, and reproducible manner.

  12. Internal standard capillary electrophoresis as a high-throughput method for pKa determination in drug discovery and development.

    PubMed

    Cabot, Joan M; Fuguet, Elisabet; Rosés, Martí

    2014-10-13

    A novel high-throughput method for determining acidity constants (pKa) by capillary electrophoresis (CE) is developed. The method, based on the use of an internal standard (IS-CE), is implemented as a routine method for accurate experimental pKa determination of drugs undergoing physicochemical measurements in drug discovery laboratories. Just two electropherograms at 2 different pH values are needed to calculate an acidity constant. Several ISs can be used in the same buffer and run to enhance precision. With 3 ISs, for example, the pKa of the test compound (TC) can be obtained in triplicate in less than 3 min of electrophoresis. It has been demonstrated that the IS-CE method eliminates some systematic errors, maintaining, or even increasing the precision of the results compared with other methods. Furthermore, pH buffer instability during electrophoretic runs is not a problem in the IS-CE method. It is also proved that after 16 h of electroseparation using the same buffer vial, pH may change by around one unit; but the pKa calculated by the IS-CE method remains constant. Thus, IS-CE is a powerful high-throughput method for pKa determination in drug discovery and development.

  13. Evolution from double to triple-antimalarial drug combinations.

    PubMed

    Shanks, G Dennis; Edstein, Michael D; Jacobus, David

    2015-03-01

    Drug combinations are used to treat multiple-drug resistant malaria parasites and to attempt to further delay the evolution of drug resistance. Most current antimalarial combinations are binary but it is likely that new triple drug combinations will be required in the future. A review of previous triple combinations of antimalarial drugs was done to focus attention on past problems and possible future combinations. The advantages of such triple drug combinations include greater efficacy against multiple-drug resistant strains, synergistic action between the different medications and simplification of the regimen so that it could be administered under direct observation and possibly as single-dose therapy. The disadvantages of poly-pharmacy include increased cost of medication, difficulty preparing robust regulatory packages and problems constructing combined formulations due to drug-drug interactions. Given the arrival of artemisinin tolerance/resistance in Southeast Asia, it is likely that new drugs introduced for malaria treatment will be in triple drug combinations. PMID:25549631

  14. Combinatorial high-throughput experimental and bioinformatic approach identifies molecular pathways linked with the sensitivity to anticancer target drugs

    PubMed Central

    Venkova, Larisa; Aliper, Alexander; Suntsova, Maria; Kholodenko, Roman; Shepelin, Denis; Borisov, Nicolas; Malakhova, Galina; Vasilov, Raif; Roumiantsev, Sergey; Zhavoronkov, Alex; Buzdin, Anton

    2015-01-01

    Effective choice of anticancer drugs is important problem of modern medicine. We developed a method termed OncoFinder for the analysis of new type of biomarkers reflecting activation of intracellular signaling and metabolic molecular pathways. These biomarkers may be linked with the sensitivity to anticancer drugs. In this study, we compared the experimental data obtained in our laboratory and in the Genomics of Drug Sensitivity in Cancer (GDS) project for testing response to anticancer drugs and transcriptomes of various human cell lines. The microarray-based profiling of transcriptomes was performed for the cell lines before the addition of drugs to the medium, and experimental growth inhibition curves were built for each drug, featuring characteristic IC50 values. We assayed here four target drugs - Pazopanib, Sorafenib, Sunitinib and Temsirolimus, and 238 different cell lines, of which 11 were profiled in our laboratory and 227 - in GDS project. Using the OncoFinder-processed transcriptomic data on ∼600 molecular pathways, we identified pathways showing significant correlation between pathway activation strength (PAS) and IC50 values for these drugs. Correlations reflect relationships between response to drug and pathway activation features. We intersected the results and found molecular pathways significantly correlated in both our assay and GDS project. For most of these pathways, we generated molecular models of their interaction with known molecular target(s) of the respective drugs. For the first time, our study uncovered mechanisms underlying cancer cell response to drugs at the high-throughput molecular interactomic level. PMID:26317900

  15. Combinatorial high-throughput experimental and bioinformatic approach identifies molecular pathways linked with the sensitivity to anticancer target drugs.

    PubMed

    Venkova, Larisa; Aliper, Alexander; Suntsova, Maria; Kholodenko, Roman; Shepelin, Denis; Borisov, Nicolas; Malakhova, Galina; Vasilov, Raif; Roumiantsev, Sergey; Zhavoronkov, Alex; Buzdin, Anton

    2015-09-29

    Effective choice of anticancer drugs is important problem of modern medicine. We developed a method termed OncoFinder for the analysis of new type of biomarkers reflecting activation of intracellular signaling and metabolic molecular pathways. These biomarkers may be linked with the sensitivity to anticancer drugs. In this study, we compared the experimental data obtained in our laboratory and in the Genomics of Drug Sensitivity in Cancer (GDS) project for testing response to anticancer drugs and transcriptomes of various human cell lines. The microarray-based profiling of transcriptomes was performed for the cell lines before the addition of drugs to the medium, and experimental growth inhibition curves were built for each drug, featuring characteristic IC50 values. We assayed here four target drugs - Pazopanib, Sorafenib, Sunitinib and Temsirolimus, and 238 different cell lines, of which 11 were profiled in our laboratory and 227 - in GDS project. Using the OncoFinder-processed transcriptomic data on ~600 molecular pathways, we identified pathways showing significant correlation between pathway activation strength (PAS) and IC50 values for these drugs. Correlations reflect relationships between response to drug and pathway activation features. We intersected the results and found molecular pathways significantly correlated in both our assay and GDS project. For most of these pathways, we generated molecular models of their interaction with known molecular target(s) of the respective drugs. For the first time, our study uncovered mechanisms underlying cancer cell response to drugs at the high-throughput molecular interactomic level. PMID:26317900

  16. High-throughput identification of off-targets for the mechanistic study of severe adverse drug reactions induced by analgesics

    SciTech Connect

    Pan, Jian-Bo; Ji, Nan; Pan, Wen; Hong, Ru; Wang, Hao; Ji, Zhi-Liang

    2014-01-01

    Drugs may induce adverse drug reactions (ADRs) when they unexpectedly bind to proteins other than their therapeutic targets. Identification of these undesired protein binding partners, called off-targets, can facilitate toxicity assessment in the early stages of drug development. In this study, a computational framework was introduced for the exploration of idiosyncratic mechanisms underlying analgesic-induced severe adverse drug reactions (SADRs). The putative analgesic-target interactions were predicted by performing reverse docking of analgesics or their active metabolites against human/mammal protein structures in a high-throughput manner. Subsequently, bioinformatics analyses were undertaken to identify ADR-associated proteins (ADRAPs) and pathways. Using the pathways and ADRAPs that this analysis identified, the mechanisms of SADRs such as cardiac disorders were explored. For instance, 53 putative ADRAPs and 24 pathways were linked with cardiac disorders, of which 10 ADRAPs were confirmed by previous experiments. Moreover, it was inferred that pathways such as base excision repair, glycolysis/glyconeogenesis, ErbB signaling, calcium signaling, and phosphatidyl inositol signaling likely play pivotal roles in drug-induced cardiac disorders. In conclusion, our framework offers an opportunity to globally understand SADRs at the molecular level, which has been difficult to realize through experiments. It also provides some valuable clues for drug repurposing. - Highlights: • A novel computational framework was developed for mechanistic study of SADRs. • Off-targets of drugs were identified in large scale and in a high-throughput manner. • SADRs like cardiac disorders were systematically explored in molecular networks. • A number of ADR-associated proteins were identified.

  17. A high throughput solubility assay for drug discovery using microscale shake-flask and rapid UHPLC-UV-CLND quantification.

    PubMed

    Lin, Baiwei; Pease, Joseph H

    2016-04-15

    The rapid determination of key physical properties of lead compounds is essential to the drug discovery process. Solubility is one of the most important properties since good solubility is needed not only for obtaining reliable in vitro and in vivo assay results in early discovery but also to ensure sufficient concentration of the drug being in circulation to get the desired therapeutic exposure at the target of interest. In order for medicinal chemists to tune solubility of lead compounds, a rapid assay is needed to provide solubility data that is accurate and predictive so that it can be reliably used for designing the next generation of compounds with improved properties. To ensure speed and data quality, we developed a high throughput solubility assay that utilizes a single calibration UHPLC-UV-CLND method and a 24h shake-flask format for rapid quantification. A set of 46 model compounds was used to demonstrate that the method is accurate, reproducible and predictive. Here we present development of the assay, including evaluation of quantification method, filtration membranes, equilibrium times, DMSO concentrations, and buffer conditions. A comparison of thermodynamic solubility results to our high throughput 24h shake-flask solubility assay results is also discussed.

  18. Antimicrobial peptides: a new class of antimalarial drugs?

    PubMed Central

    Vale, Nuno; Aguiar, Luísa; Gomes, Paula

    2014-01-01

    A range of antimicrobial peptides (AMP) exhibit activity on malaria parasites, Plasmodium spp., in their blood or mosquito stages, or both. These peptides include a diverse array of both natural and synthetic molecules varying greatly in size, charge, hydrophobicity, and secondary structure features. Along with an overview of relevant literature reports regarding AMP that display antiplasmodial activity, this review makes a few considerations about those molecules as a potential new class of antimalarial drugs. PMID:25566072

  19. An implantable microdevice to perform high-throughput in vivo drug sensitivity testing in tumors

    PubMed Central

    Jonas, Oliver; Landry, Heather M.; Fuller, Jason E.; Santini, John T.; Baselga, Jose; Tepper, Robert I.; Cima, Michael J.; Langer, Robert

    2016-01-01

    Current anticancer chemotherapy relies on a limited set of in vitro or indirect prognostic markers of tumor response to available drugs. A more accurate analysis of drug sensitivity would involve studying tumor response in vivo. To this end, we have developed an implantable device that can perform drug sensitivity testing of several anticancer agents simultaneously inside the living tumor. The device contained reservoirs that released microdoses of single agents or drug combinations into spatially distinct regions of the tumor. The local drug concentrations were chosen to be representative of concentrations achieved during systemic treatment. Local efficacy and drug concentration profiles were evaluated for each drug or drug combination on the device, and the local efficacy was confirmed to be a predictor of systemic efficacy in vivo for multiple drugs and tumor models. Currently, up to 16 individual drugs or combinations can be assessed independently, without systemic drug exposure, through minimally invasive biopsy of a small region of a single tumor. This assay takes into consideration physiologic effects that contribute to drug response by allowing drugs to interact with the living tumor in its native microenvironment. Because these effects are crucial to predicting drug response, we envision that these devices will help identify optimal drug therapy before systemic treatment is initiated and could improve drug response prediction beyond the biomarkers and in vitro and ex vivo studies used today. These devices may also be used in clinical drug development to safely gather efficacy data on new compounds before pharmacological optimization. PMID:25904741

  20. An implantable microdevice to perform high-throughput in vivo drug sensitivity testing in tumors.

    PubMed

    Jonas, Oliver; Landry, Heather M; Fuller, Jason E; Santini, John T; Baselga, Jose; Tepper, Robert I; Cima, Michael J; Langer, Robert

    2015-04-22

    Current anticancer chemotherapy relies on a limited set of in vitro or indirect prognostic markers of tumor response to available drugs. A more accurate analysis of drug sensitivity would involve studying tumor response in vivo. To this end, we have developed an implantable device that can perform drug sensitivity testing of several anticancer agents simultaneously inside the living tumor. The device contained reservoirs that released microdoses of single agents or drug combinations into spatially distinct regions of the tumor. The local drug concentrations were chosen to be representative of concentrations achieved during systemic treatment. Local efficacy and drug concentration profiles were evaluated for each drug or drug combination on the device, and the local efficacy was confirmed to be a predictor of systemic efficacy in vivo for multiple drugs and tumor models. Currently, up to 16 individual drugs or combinations can be assessed independently, without systemic drug exposure, through minimally invasive biopsy of a small region of a single tumor. This assay takes into consideration physiologic effects that contribute to drug response by allowing drugs to interact with the living tumor in its native microenvironment. Because these effects are crucial to predicting drug response, we envision that these devices will help identify optimal drug therapy before systemic treatment is initiated and could improve drug response prediction beyond the biomarkers and in vitro and ex vivo studies used today. These devices may also be used in clinical drug development to safely gather efficacy data on new compounds before pharmacological optimization. PMID:25904741

  1. Quantifying the pharmacology of antimalarial drug combination therapy

    NASA Astrophysics Data System (ADS)

    Hastings, Ian M.; Hodel, Eva Maria; Kay, Katherine

    2016-09-01

    Most current antimalarial drugs are combinations of an artemisinin plus a ‘partner’ drug from another class, and are known as artemisinin-based combination therapies (ACTs). They are the frontline drugs in treating human malaria infections. They also have a public-health role as an essential component of recent, comprehensive scale-ups of malaria interventions and containment efforts conceived as part of longer term malaria elimination efforts. Recent reports that resistance has arisen to artemisinins has caused considerable concern. We investigate the likely impact of artemisinin resistance by quantifying the contribution artemisinins make to the overall therapeutic capacity of ACTs. We achieve this using a simple, easily understood, algebraic approach and by more sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two approaches gave consistent results. Surprisingly, the artemisinin component typically makes a negligible contribution (≪0.0001%) to the therapeutic capacity of the most widely used ACTs and only starts to make a significant contribution to therapeutic outcome once resistance has started to evolve to the partner drugs. The main threat to antimalarial drug effectiveness and control comes from resistance evolving to the partner drugs. We therefore argue that public health policies be re-focussed to maximise the likely long-term effectiveness of the partner drugs.

  2. Quantifying the pharmacology of antimalarial drug combination therapy.

    PubMed

    Hastings, Ian M; Hodel, Eva Maria; Kay, Katherine

    2016-01-01

    Most current antimalarial drugs are combinations of an artemisinin plus a 'partner' drug from another class, and are known as artemisinin-based combination therapies (ACTs). They are the frontline drugs in treating human malaria infections. They also have a public-health role as an essential component of recent, comprehensive scale-ups of malaria interventions and containment efforts conceived as part of longer term malaria elimination efforts. Recent reports that resistance has arisen to artemisinins has caused considerable concern. We investigate the likely impact of artemisinin resistance by quantifying the contribution artemisinins make to the overall therapeutic capacity of ACTs. We achieve this using a simple, easily understood, algebraic approach and by more sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two approaches gave consistent results. Surprisingly, the artemisinin component typically makes a negligible contribution (≪0.0001%) to the therapeutic capacity of the most widely used ACTs and only starts to make a significant contribution to therapeutic outcome once resistance has started to evolve to the partner drugs. The main threat to antimalarial drug effectiveness and control comes from resistance evolving to the partner drugs. We therefore argue that public health policies be re-focussed to maximise the likely long-term effectiveness of the partner drugs. PMID:27604175

  3. Quantifying the pharmacology of antimalarial drug combination therapy

    PubMed Central

    Hastings, Ian M.; Hodel, Eva Maria; Kay, Katherine

    2016-01-01

    Most current antimalarial drugs are combinations of an artemisinin plus a ‘partner’ drug from another class, and are known as artemisinin-based combination therapies (ACTs). They are the frontline drugs in treating human malaria infections. They also have a public-health role as an essential component of recent, comprehensive scale-ups of malaria interventions and containment efforts conceived as part of longer term malaria elimination efforts. Recent reports that resistance has arisen to artemisinins has caused considerable concern. We investigate the likely impact of artemisinin resistance by quantifying the contribution artemisinins make to the overall therapeutic capacity of ACTs. We achieve this using a simple, easily understood, algebraic approach and by more sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two approaches gave consistent results. Surprisingly, the artemisinin component typically makes a negligible contribution (≪0.0001%) to the therapeutic capacity of the most widely used ACTs and only starts to make a significant contribution to therapeutic outcome once resistance has started to evolve to the partner drugs. The main threat to antimalarial drug effectiveness and control comes from resistance evolving to the partner drugs. We therefore argue that public health policies be re-focussed to maximise the likely long-term effectiveness of the partner drugs. PMID:27604175

  4. Design and use of electrochemical sensors in enantioselective high throughput screening of drugs. A minireview.

    PubMed

    Stefana, R I; van Staden, J L; Aboul-Enein, H Y

    2000-12-01

    The importance of reliable detection systems for enantiomeric assays increases with the necessity of high throughput screening analysis of raw materials for the pharmaceutical industry. The utilization of electrochemical sensors in enantioselective analysis is an accurate and precise alternative to chromatographic techniques. The reliability of the response characteristics as well as of the analytical information obtained by using electrochemical sensors is strictly correlated with the design of the sensors. The designs evaluated for sensors have been based on PVC, imprinting polymers and carbon paste matrices. Among these, carbon paste sensors have been the most reliable and have been utilized for the construction of potentiometric, enantioselective membrane electrodes as well as for amperometric biosensors, and immunosensors. There are two ways to use the electrochemical sensors in enantioselective screening analysis: selective binding and catalyst selectivity. A molecule with a special chemical architecture is required for selective binding: a lock for a key. The high reliability of analytical information obtained using these sensors has made possible the automation of potentiometric and amperometric techniques by integration of enantioselective sensors as detectors in flow injection analysis and sequential injection analysis techniques.

  5. In Vitro High-Throughput RNAi Screening to Accelerate the Process of Target Identification and Drug Development.

    PubMed

    Yin, Hongwei; Kassner, Michelle

    2016-01-01

    High-throughput RNA interference (HT-RNAi) is a powerful tool that can be used to knock down gene expression in order to identify novel genes and pathways involved in many cellular processes. It is a systematic, yet unbiased, approach to identify essential or synthetic lethal genes that promote cell survival in diseased cells as well as genes that confer resistance or sensitivity to drug treatment. This information serves as a foundation for enhancing current treatments for cancer and other diseases by identifying new drug targets, uncovering potential combination therapies, and helping clinicians match patients with the most effective treatment based on genetic information. Here, we describe the method of performing an in vitro HT-RNAi screen using chemically synthesized siRNA. PMID:27581290

  6. Antimalarial drugs for rheumatoid disease during pregnancy.

    PubMed Central

    Koren, G.

    1999-01-01

    QUESTION: One of my patients, who has rheumatoid arthritis, has just found out she is pregnant. She is being treated with hydroxychloroquine. I could not find anything about the safety of this drug during pregnancy. ANSWER: Most of the literature on this drug relates to prophylaxis for malaria. Much lower doses than those used for rheumatic diseases are given with no adverse fetal effects. Several studies on use of the drug for rheumatic diseases during pregnancy also failed to show adverse fetal effects, although, in most cases, only first-trimester exposure was reported. PMID:10626050

  7. A High-Throughput Cell-Based Method to Predict the Unbound Drug Fraction in the Brain

    PubMed Central

    2014-01-01

    Optimization of drug efficacy in the brain requires understanding of the local exposure to unbound drug at the site of action. This relies on measurements of the unbound drug fraction (fu,brain), which currently requires access to brain tissue. Here, we present a novel methodology using homogenates of cultured cells for rapid estimation of fu,brain. In our setup, drug binding to human embryonic kidney cell (HEK293) homogenate was measured in a small-scale dialysis apparatus. To increase throughput, we combined drugs into cassettes for simultaneous measurement of multiple compounds. Our method estimated fu,brain with an average error of 1.9-fold. We propose that our simple method can be used as an inexpensive, easily available and high-throughput alternative to brain tissues excised from laboratory animals. Thereby, estimates of unbound drug exposure can now be implemented at a much earlier stage of the drug discovery process, when molecular property changes are easier to make. PMID:24601604

  8. Quality of antimalarials at the epicenter of antimalarial drug resistance: results from an overt and mystery client survey in Cambodia.

    PubMed

    Yeung, Shunmay; Lawford, Harriet L S; Tabernero, Patricia; Nguon, Chea; van Wyk, Albert; Malik, Naiela; DeSousa, Mikhael; Rada, Ouk; Boravann, Mam; Dwivedi, Prabha; Hostetler, Dana M; Swamidoss, Isabel; Green, Michael D; Fernandez, Facundo M; Kaur, Harparkash

    2015-06-01

    Widespread availability of monotherapies and falsified antimalarials is thought to have contributed to the historical development of multidrug-resistant malaria in Cambodia. This study aimed to document the quality of artemisinin-containing antimalarials (ACAs) and to compare two methods of collecting antimalarials from drug outlets: through open surveyors and mystery clients (MCs). Few oral artemisinin-based monotherapies and no suspected falsified medicines were found. All 291 samples contained the stated active pharmaceutical ingredient (API) of which 69% were considered good quality by chemical analysis. Overall, medicine quality did not differ by collection method, although open surveyors were less likely to obtain oral artemisinin-based monotherapies than MCs. The results are an encouraging indication of the positive impact of the country's efforts to tackle falsified antimalarials and artemisinin-based monotherapies. However, poor-quality medicines remain an ongoing challenge that demands sustained political will and investment of human and financial resources.

  9. Quality of Antimalarials at the Epicenter of Antimalarial Drug Resistance: Results from an Overt and Mystery Client Survey in Cambodia

    PubMed Central

    Yeung, Shunmay; Lawford, Harriet L. S.; Tabernero, Patricia; Nguon, Chea; van Wyk, Albert; Malik, Naiela; DeSousa, Mikhael; Rada, Ouk; Boravann, Mam; Dwivedi, Prabha; Hostetler, Dana M.; Swamidoss, Isabel; Green, Michael D.; Fernandez, Facundo M.; Kaur, Harparkash

    2015-01-01

    Widespread availability of monotherapies and falsified antimalarials is thought to have contributed to the historical development of multidrug-resistant malaria in Cambodia. This study aimed to document the quality of artemisinin-containing antimalarials (ACAs) and to compare two methods of collecting antimalarials from drug outlets: through open surveyors and mystery clients (MCs). Few oral artemisinin-based monotherapies and no suspected falsified medicines were found. All 291 samples contained the stated active pharmaceutical ingredient (API) of which 69% were considered good quality by chemical analysis. Overall, medicine quality did not differ by collection method, although open surveyors were less likely to obtain oral artemisinin-based monotherapies than MCs. The results are an encouraging indication of the positive impact of the country's efforts to tackle falsified antimalarials and artemisinin-based monotherapies. However, poor-quality medicines remain an ongoing challenge that demands sustained political will and investment of human and financial resources. PMID:25897063

  10. Human genetics in rheumatoid arthritis guides a high-throughput drug screen of the CD40 signaling pathway.

    PubMed

    Li, Gang; Diogo, Dorothée; Wu, Di; Spoonamore, Jim; Dancik, Vlado; Franke, Lude; Kurreeman, Fina; Rossin, Elizabeth J; Duclos, Grant; Hartland, Cathy; Zhou, Xuezhong; Li, Kejie; Liu, Jun; De Jager, Philip L; Siminovitch, Katherine A; Zhernakova, Alexandra; Raychaudhuri, Soumya; Bowes, John; Eyre, Steve; Padyukov, Leonid; Gregersen, Peter K; Worthington, Jane; Gupta, Namrata; Clemons, Paul A; Stahl, Eli; Tolliday, Nicola; Plenge, Robert M

    2013-05-01

    Although genetic and non-genetic studies in mouse and human implicate the CD40 pathway in rheumatoid arthritis (RA), there are no approved drugs that inhibit CD40 signaling for clinical care in RA or any other disease. Here, we sought to understand the biological consequences of a CD40 risk variant in RA discovered by a previous genome-wide association study (GWAS) and to perform a high-throughput drug screen for modulators of CD40 signaling based on human genetic findings. First, we fine-map the CD40 risk locus in 7,222 seropositive RA patients and 15,870 controls, together with deep sequencing of CD40 coding exons in 500 RA cases and 650 controls, to identify a single SNP that explains the entire signal of association (rs4810485, P = 1.4×10(-9)). Second, we demonstrate that subjects homozygous for the RA risk allele have ∼33% more CD40 on the surface of primary human CD19+ B lymphocytes than subjects homozygous for the non-risk allele (P = 10(-9)), a finding corroborated by expression quantitative trait loci (eQTL) analysis in peripheral blood mononuclear cells from 1,469 healthy control individuals. Third, we use retroviral shRNA infection to perturb the amount of CD40 on the surface of a human B lymphocyte cell line (BL2) and observe a direct correlation between amount of CD40 protein and phosphorylation of RelA (p65), a subunit of the NF-κB transcription factor. Finally, we develop a high-throughput NF-κB luciferase reporter assay in BL2 cells activated with trimerized CD40 ligand (tCD40L) and conduct an HTS of 1,982 chemical compounds and FDA-approved drugs. After a series of counter-screens and testing in primary human CD19+ B cells, we identify 2 novel chemical inhibitors not previously implicated in inflammation or CD40-mediated NF-κB signaling. Our study demonstrates proof-of-concept that human genetics can be used to guide the development of phenotype-based, high-throughput small-molecule screens to identify potential novel therapies in

  11. Human Genetics in Rheumatoid Arthritis Guides a High-Throughput Drug Screen of the CD40 Signaling Pathway

    PubMed Central

    Li, Gang; Diogo, Dorothée; Wu, Di; Spoonamore, Jim; Dancik, Vlado; Franke, Lude; Kurreeman, Fina; Rossin, Elizabeth J.; Duclos, Grant; Hartland, Cathy; Zhou, Xuezhong; Li, Kejie; Liu, Jun; De Jager, Philip L.; Siminovitch, Katherine A.; Zhernakova, Alexandra; Raychaudhuri, Soumya; Bowes, John; Eyre, Steve; Padyukov, Leonid; Gregersen, Peter K.; Worthington, Jane; Gupta, Namrata; Clemons, Paul A.; Stahl, Eli; Tolliday, Nicola; Plenge, Robert M.

    2013-01-01

    Although genetic and non-genetic studies in mouse and human implicate the CD40 pathway in rheumatoid arthritis (RA), there are no approved drugs that inhibit CD40 signaling for clinical care in RA or any other disease. Here, we sought to understand the biological consequences of a CD40 risk variant in RA discovered by a previous genome-wide association study (GWAS) and to perform a high-throughput drug screen for modulators of CD40 signaling based on human genetic findings. First, we fine-map the CD40 risk locus in 7,222 seropositive RA patients and 15,870 controls, together with deep sequencing of CD40 coding exons in 500 RA cases and 650 controls, to identify a single SNP that explains the entire signal of association (rs4810485, P = 1.4×10−9). Second, we demonstrate that subjects homozygous for the RA risk allele have ∼33% more CD40 on the surface of primary human CD19+ B lymphocytes than subjects homozygous for the non-risk allele (P = 10−9), a finding corroborated by expression quantitative trait loci (eQTL) analysis in peripheral blood mononuclear cells from 1,469 healthy control individuals. Third, we use retroviral shRNA infection to perturb the amount of CD40 on the surface of a human B lymphocyte cell line (BL2) and observe a direct correlation between amount of CD40 protein and phosphorylation of RelA (p65), a subunit of the NF-κB transcription factor. Finally, we develop a high-throughput NF-κB luciferase reporter assay in BL2 cells activated with trimerized CD40 ligand (tCD40L) and conduct an HTS of 1,982 chemical compounds and FDA–approved drugs. After a series of counter-screens and testing in primary human CD19+ B cells, we identify 2 novel chemical inhibitors not previously implicated in inflammation or CD40-mediated NF-κB signaling. Our study demonstrates proof-of-concept that human genetics can be used to guide the development of phenotype-based, high-throughput small-molecule screens to identify potential novel therapies in

  12. High-Throughput 3D Screening Reveals Differences in Drug Sensitivities between Culture Models of JIMT1 Breast Cancer Cells

    PubMed Central

    Fey, Vidal; Mpindi, John-Patrick; Kleivi Sahlberg, Kristine; Kallioniemi, Olli; Perälä, Merja

    2013-01-01

    The traditional method for studying cancer in vitro is to grow immortalized cancer cells in two-dimensional monolayers on plastic. However, many cellular features are impaired in these artificial conditions, and large changes in gene expression compared to tumors have been reported. Three-dimensional cell culture models have become increasingly popular and are suggested to be better models than two-dimensional monolayers due to improved cell-to-cell contact and structures that resemble in vivo architecture. The aim of this study was to develop a simple high-throughput three-dimensional drug screening method and to compare drug responses in JIMT1 breast cancer cells when grown in two dimensions, in poly(2-hydroxyethyl methacrylate) induced anchorage-independent three-dimensional models, and in Matrigel three-dimensional cell culture models. We screened 102 compounds with multiple concentrations and biological replicates for their effects on cell proliferation. The cells were either treated immediately upon plating, or they were allowed to grow in three-dimensional cultures for 4 days before the drug treatment. Large variations in drug responses were observed between the models indicating that comparisons of culture model-influenced drug sensitivities cannot be made based on the effects of a single drug. However, we show with the 63 most prominent drugs that, in general, JIMT1 cells grown on Matrigel were significantly more sensitive to drugs than cells grown in two-dimensional cultures, while the responses of cells grown in poly(2-hydroxyethyl methacrylate) resembled those of the two-dimensional cultures. Furthermore, comparing the gene expression profiles of the cell culture models to xenograft tumors indicated that cells cultured in Matrigel and as xenografts most closely resembled each other. In this study, we also suggest that three-dimensional cultures can provide a platform for systematic experimentation of larger compound collections in a high-throughput mode

  13. A New Set of Chemical Starting Points with Plasmodium falciparum Transmission-Blocking Potential for Antimalarial Drug Discovery.

    PubMed

    Almela, Maria Jesus; Lozano, Sonia; Lelièvre, Joël; Colmenarejo, Gonzalo; Coterón, José Miguel; Rodrigues, Janneth; Gonzalez, Carolina; Herreros, Esperanza

    2015-01-01

    The discovery of new antimalarials with transmission blocking activity remains a key issue in efforts to control malaria and eventually eradicate the disease. Recently, high-throughput screening (HTS) assays have been successfully applied to Plasmodium falciparum asexual stages to screen millions of compounds, with the identification of thousands of new active molecules, some of which are already in clinical phases. The same approach has now been applied to identify compounds that are active against P. falciparum gametocytes, the parasite stage responsible for transmission. This study reports screening results for the Tres Cantos Antimalarial Set (TCAMS), of approximately 13,533 molecules, against P. falciparum stage V gametocytes. Secondary confirmation and cytotoxicity assays led to the identification of 98 selective molecules with dual activity against gametocytes and asexual stages. Hit compounds were chemically clustered and analyzed for appropriate physicochemical properties. The TCAMS chemical space around the prioritized hits was also studied. A selection of hit compounds was assessed ex vivo in the standard membrane feeding assay and demonstrated complete block in transmission. As a result of this effort, new chemical structures not connected to previously described antimalarials have been identified. This new set of compounds may serve as starting points for future drug discovery programs as well as tool compounds for identifying new modes of action involved in malaria transmission. PMID:26317851

  14. A New Set of Chemical Starting Points with Plasmodium falciparum Transmission-Blocking Potential for Antimalarial Drug Discovery

    PubMed Central

    Almela, Maria Jesus; Lozano, Sonia; Lelièvre, Joël; Colmenarejo, Gonzalo; Coterón, José Miguel; Rodrigues, Janneth; Gonzalez, Carolina; Herreros, Esperanza

    2015-01-01

    The discovery of new antimalarials with transmission blocking activity remains a key issue in efforts to control malaria and eventually eradicate the disease. Recently, high-throughput screening (HTS) assays have been successfully applied to Plasmodium falciparum asexual stages to screen millions of compounds, with the identification of thousands of new active molecules, some of which are already in clinical phases. The same approach has now been applied to identify compounds that are active against P. falciparum gametocytes, the parasite stage responsible for transmission. This study reports screening results for the Tres Cantos Antimalarial Set (TCAMS), of approximately 13,533 molecules, against P. falciparum stage V gametocytes. Secondary confirmation and cytotoxicity assays led to the identification of 98 selective molecules with dual activity against gametocytes and asexual stages. Hit compounds were chemically clustered and analyzed for appropriate physicochemical properties. The TCAMS chemical space around the prioritized hits was also studied. A selection of hit compounds was assessed ex vivo in the standard membrane feeding assay and demonstrated complete block in transmission. As a result of this effort, new chemical structures not connected to previously described antimalarials have been identified. This new set of compounds may serve as starting points for future drug discovery programs as well as tool compounds for identifying new modes of action involved in malaria transmission. PMID:26317851

  15. High throughput screening for inhibitors of the HECT ubiquitin E3 ligase ITCH identifies antidepressant drugs as regulators of autophagy

    PubMed Central

    Rossi, M; Rotblat, B; Ansell, K; Amelio, I; Caraglia, M; Misso, G; Bernassola, F; Cavasotto, C N; Knight, R A; Ciechanover, A; Melino, G

    2014-01-01

    Inhibition of distinct ubiquitin E3 ligases might represent a powerful therapeutic tool. ITCH is a HECT domain-containing E3 ligase that promotes the ubiquitylation and degradation of several proteins, including p73, p63, c-Jun, JunB, Notch and c-FLIP, thus affecting cell fate. Accordingly, ITCH depletion potentiates the effect of chemotherapeutic drugs, revealing ITCH as a potential pharmacological target in cancer therapy. Using high throughput screening of ITCH auto-ubiquitylation, we identified several putative ITCH inhibitors, one of which is clomipramine—a clinically useful antidepressant drug. Previously, we have shown that clomipramine inhibits autophagy by blocking autophagolysosomal fluxes and thus could potentiate chemotherapy in vitro. Here, we found that clomipramine specifically blocks ITCH auto-ubiquitylation, as well as p73 ubiquitylation. By screening structural homologs of clomipramine, we identified several ITCH inhibitors and putative molecular moieties that are essential for ITCH inhibition. Treating a panel of breast, prostate and bladder cancer cell lines with clomipramine, or its homologs, we found that they reduce cancer cell growth, and synergize with gemcitabine or mitomycin in killing cancer cells by blocking autophagy. We also discuss a potential mechanism of inhibition. Together, our study (i) demonstrates the feasibility of using high throughput screening to identify E3 ligase inhibitors and (ii) provides insight into how clomipramine and its structural homologs might interfere with ITCH and other HECT E3 ligase catalytic activity in (iii) potentiating chemotherapy by regulating autophagic fluxes. These results may have direct clinical applications. PMID:24787015

  16. Biomimetic three-dimensional tissue models for advanced high-throughput drug screening

    PubMed Central

    Nam, Ki-Hwan; Smith, Alec S.T.; Lone, Saifullah; Kwon, Sunghoon; Kim, Deok-Ho

    2015-01-01

    Most current drug screening assays used to identify new drug candidates are 2D cell-based systems, even though such in vitro assays do not adequately recreate the in vivo complexity of 3D tissues. Inadequate representation of the human tissue environment during a preclinical test can result in inaccurate predictions of compound effects on overall tissue functionality. Screening for compound efficacy by focusing on a single pathway or protein target, coupled with difficulties in maintaining long-term 2D monolayers, can serve to exacerbate these issues when utilizing such simplistic model systems for physiological drug screening applications. Numerous studies have shown that cell responses to drugs in 3D culture are improved from those in 2D, with respect to modeling in vivo tissue functionality, which highlights the advantages of using 3D-based models for preclinical drug screens. In this review, we discuss the development of microengineered 3D tissue models which accurately mimic the physiological properties of native tissue samples, and highlight the advantages of using such 3D micro-tissue models over conventional cell-based assays for future drug screening applications. We also discuss biomimetic 3D environments, based-on engineered tissues as potential preclinical models for the development of more predictive drug screening assays for specific disease models. PMID:25385716

  17. Precision multidimensional assay for high-throughput microRNA drug discovery.

    PubMed

    Haefliger, Benjamin; Prochazka, Laura; Angelici, Bartolomeo; Benenson, Yaakov

    2016-01-01

    Development of drug discovery assays that combine high content with throughput is challenging. Information-processing gene networks can address this challenge by integrating multiple potential targets of drug candidates' activities into a small number of informative readouts, reporting simultaneously on specific and non-specific effects. Here we show a family of networks implementing this concept in a cell-based drug discovery assay for miRNA drug targets. The networks comprise multiple modules reporting on specific effects towards an intended miRNA target, together with non-specific effects on gene expression, off-target miRNAs and RNA interference pathway. We validate the assays using known perturbations of on- and off-target miRNAs, and evaluate an ∼700 compound library in an automated screen with a follow-up on specific and non-specific hits. We further customize and validate assays for additional drug targets and non-specific inputs. Our study offers a novel framework for precision drug discovery assays applicable to diverse target families. PMID:26880188

  18. Precision multidimensional assay for high-throughput microRNA drug discovery.

    PubMed

    Haefliger, Benjamin; Prochazka, Laura; Angelici, Bartolomeo; Benenson, Yaakov

    2016-01-01

    Development of drug discovery assays that combine high content with throughput is challenging. Information-processing gene networks can address this challenge by integrating multiple potential targets of drug candidates' activities into a small number of informative readouts, reporting simultaneously on specific and non-specific effects. Here we show a family of networks implementing this concept in a cell-based drug discovery assay for miRNA drug targets. The networks comprise multiple modules reporting on specific effects towards an intended miRNA target, together with non-specific effects on gene expression, off-target miRNAs and RNA interference pathway. We validate the assays using known perturbations of on- and off-target miRNAs, and evaluate an ∼700 compound library in an automated screen with a follow-up on specific and non-specific hits. We further customize and validate assays for additional drug targets and non-specific inputs. Our study offers a novel framework for precision drug discovery assays applicable to diverse target families.

  19. Precision multidimensional assay for high-throughput microRNA drug discovery

    PubMed Central

    Haefliger, Benjamin; Prochazka, Laura; Angelici, Bartolomeo; Benenson, Yaakov

    2016-01-01

    Development of drug discovery assays that combine high content with throughput is challenging. Information-processing gene networks can address this challenge by integrating multiple potential targets of drug candidates' activities into a small number of informative readouts, reporting simultaneously on specific and non-specific effects. Here we show a family of networks implementing this concept in a cell-based drug discovery assay for miRNA drug targets. The networks comprise multiple modules reporting on specific effects towards an intended miRNA target, together with non-specific effects on gene expression, off-target miRNAs and RNA interference pathway. We validate the assays using known perturbations of on- and off-target miRNAs, and evaluate an ∼700 compound library in an automated screen with a follow-up on specific and non-specific hits. We further customize and validate assays for additional drug targets and non-specific inputs. Our study offers a novel framework for precision drug discovery assays applicable to diverse target families. PMID:26880188

  20. The Oral Antimalarial Drug Tafenoquine Shows Activity against Trypanosoma brucei

    PubMed Central

    Carvalho, Luis; Martínez-García, Marta; Pérez-Victoria, Ignacio; Manzano, José Ignacio; Yardley, Vanessa

    2015-01-01

    The protozoan parasite Trypanosoma brucei causes human African trypanosomiasis, or sleeping sickness, a neglected tropical disease that requires new, safer, and more effective treatments. Repurposing oral drugs could reduce both the time and cost involved in sleeping sickness drug discovery. Tafenoquine (TFQ) is an oral antimalarial drug belonging to the 8-aminoquinoline family which is currently in clinical phase III. We show here that TFQ efficiently kills different T. brucei spp. in the submicromolar concentration range. Our results suggest that TFQ accumulates into acidic compartments and induces a necrotic process involving cell membrane disintegration and loss of cytoplasmic content, leading to parasite death. Cell lysis is preceded by a wide and multitarget drug action, affecting the lysosome, mitochondria, and acidocalcisomes and inducing a depolarization of the mitochondrial membrane potential, elevation of intracellular Ca2+, and production of reactive oxygen species. This is the first report of an 8-aminoquinoline demonstrating significant in vitro activity against T. brucei. PMID:26195527

  1. The Oral Antimalarial Drug Tafenoquine Shows Activity against Trypanosoma brucei.

    PubMed

    Carvalho, Luis; Martínez-García, Marta; Pérez-Victoria, Ignacio; Manzano, José Ignacio; Yardley, Vanessa; Gamarro, Francisco; Pérez-Victoria, José M

    2015-10-01

    The protozoan parasite Trypanosoma brucei causes human African trypanosomiasis, or sleeping sickness, a neglected tropical disease that requires new, safer, and more effective treatments. Repurposing oral drugs could reduce both the time and cost involved in sleeping sickness drug discovery. Tafenoquine (TFQ) is an oral antimalarial drug belonging to the 8-aminoquinoline family which is currently in clinical phase III. We show here that TFQ efficiently kills different T. brucei spp. in the submicromolar concentration range. Our results suggest that TFQ accumulates into acidic compartments and induces a necrotic process involving cell membrane disintegration and loss of cytoplasmic content, leading to parasite death. Cell lysis is preceded by a wide and multitarget drug action, affecting the lysosome, mitochondria, and acidocalcisomes and inducing a depolarization of the mitochondrial membrane potential, elevation of intracellular Ca(2+), and production of reactive oxygen species. This is the first report of an 8-aminoquinoline demonstrating significant in vitro activity against T. brucei. PMID:26195527

  2. An Organotypic High Throughput System for Characterization of Drug Sensitivity of Primary Multiple Myeloma Cells.

    PubMed

    Silva, Ariosto; Jacobson, Timothy; Meads, Mark; Distler, Allison; Shain, Kenneth

    2015-01-01

    In this work we describe a novel approach that combines ex vivo drug sensitivity assays and digital image analysis to estimate chemosensitivity and heterogeneity of patient-derived multiple myeloma (MM) cells. This approach consists in seeding primary MM cells freshly extracted from bone marrow aspirates into microfluidic chambers implemented in multi-well plates, each consisting of a reconstruction of the bone marrow microenvironment, including extracellular matrix (collagen or basement membrane matrix) and stroma (patient-derived mesenchymal stem cells) or human-derived endothelial cells (HUVECs). The chambers are drugged with different agents and concentrations, and are imaged sequentially for 96 hr through bright field microscopy, in a motorized microscope equipped with a digital camera. Digital image analysis software detects live and dead cells from presence or absence of membrane motion, and generates curves of change in viability as a function of drug concentration and exposure time. We use a computational model to determine the parameters of chemosensitivity of the tumor population to each drug, as well as the number of sub-populations present as a measure of tumor heterogeneity. These patient-tailored models can then be used to simulate therapeutic regimens and estimate clinical response. PMID:26274375

  3. Antimalarial drug resistance in Bangladesh, 1996-2012.

    PubMed

    Haque, Ubydul; Glass, Gregory E; Haque, Waziul; Islam, Nazrul; Roy, Shyamal; Karim, Jahirul; Noedl, Harald

    2013-12-01

    Malaria remains an important health problem in Bangladesh, with approximately 14 million people at risk. Antimalarial drug resistance is a major obstacle to the control of malaria in endemic countries. In 2012, Bangladesh reported an estimated 29 522 malaria episodes, of which 94% were reported as being caused by Plasmodium falciparum. In this study, we reviewed and summarized antimalarial drug resistance data from Bangladesh published until June 2013. We searched published sources for data referring to any type of P. falciparum drug resistance (in vivo, in vitro, or molecular) and found 169 articles published in peer-reviewed journals. Of these, 143 articles were excluded because they did not meet our inclusion criteria. After detailed review of the remaining 26 articles, 14 were selected for evaluation. Published studies indicate that P. falciparum shows varying levels of resistance to chloroquine, mefloquine and sulfadoxine-pyrimethamine. Combination therapy of chloroquine and primaquine has proven ineffective and combinations of sulfadoxine-pyrimethamine with either quinine or chloroquine have also shown poor efficacy. Recent studies indicate that artemisinin derivatives, such as artesunate, remain highly efficacious in treating P. falciparum malaria. Available data suggest that artemisinins, quinine, doxycyline, mefloquine-artesunate and azithromycin-artesunate combination therapy remain efficacious in the treatment of P. falciparum malaria in Bangladesh.

  4. Large-scale drug screening against Babesia divergens parasite using a fluorescence-based high-throughput screening assay.

    PubMed

    Rizk, Mohamed Abdo; El-Sayed, Shimaa Abd El-Salam; AbouLaila, Mahmoud; Tuvshintulga, Bumduuren; Yokoyama, Naoaki; Igarashi, Ikuo

    2016-08-30

    The validation of a fluorescence-based high-throughput screening (HTS) assay for determining the efficacies of large chemical libraries against Babesia divergens (bovine strain) in in vitro cultures was evaluated in this study. Hematocrits (HCTs) of 2.5%, 5%, and 10% were used for the in vitro culture at 1% parasitemia without daily replacement of the medium. Linearity and HTS assay results revealed that the best HCTs were 5% and 10%. The obtained IC50 values of diminazene aceturate, either by fluorescence-based HTS assay with and without daily replacement of medium or by fluorescence- and microscopy-based methods, did not differ significantly at 5% HCT. Actinonin and chloroquine diphosphate were the most effective drugs against the in vitro growth of B. divergens, followed by pyronaridine tetraphosphate- and luteolin-treated cultures. On contrary, tetracycline hydrochloride and (-)-epigallocatechin-3-gallate from green tea exhibited poor activity as compared with diminazene aceturate (positive control drug). The data indicated that 5% HCT without daily replacement of the culture medium mixed with bovine serum in vitro using a fluorescence-based HTS assay creates the best conditions for large-scale drug screening against B. divergens that infect cattle. PMID:27523944

  5. Discovering novel neuroactive drugs through high-throughput behavior-based chemical screening in the zebrafish

    PubMed Central

    Bruni, Giancarlo; Lakhani, Parth; Kokel, David

    2014-01-01

    Most neuroactive drugs were discovered through unexpected behavioral observations. Systematic behavioral screening is inefficient in most model organisms. But, automated technologies are enabling a new phase of discovery-based research in central nervous system (CNS) pharmacology. Researchers are using large-scale behavior-based chemical screens in zebrafish to discover compounds with new structures, targets, and functions. These compounds are powerful tools for understanding CNS signaling pathways. Substantial differences between human and zebrafish biology will make it difficult to translate these discoveries to clinical medicine. However, given the molecular genetic similarities between humans and zebrafish, it is likely that some of these compounds will have translational utility. We predict that the greatest new successes in CNS drug discovery will leverage many model systems, including in vitro assays, cells, rodents, and zebrafish. PMID:25104936

  6. Poor quality drugs: grand challenges in high throughput detection, countrywide sampling, and forensics in developing countries†

    PubMed Central

    Fernandez, Facundo M.; Hostetler, Dana; Powell, Kristen; Kaur, Harparkash; Green, Michael D.; Mildenhall, Dallas C.; Newton, Paul N.

    2012-01-01

    Throughout history, poor quality medicines have been a persistent problem, with periodical crises in the supply of antimicrobials, such as fake cinchona bark in the 1600s and fake quinine in the 1800s. Regrettably, this problem seems to have grown in the last decade, especially afflicting unsuspecting patients and those seeking medicines via on-line pharmacies. Here we discuss some of the challenges related to the fight against poor quality drugs, and counterfeits in particular, with an emphasis on the analytical tools available, their relative performance, and the necessary workflows needed for distinguishing between genuine, substandard, degraded and counterfeit medicines. PMID:21107455

  7. Targeting serpins in high-throughput and structure-based drug design.

    PubMed

    Chang, Yi-Pin; Mahadeva, Ravi; Patschull, Anathe O M; Nobeli, Irene; Ekeowa, Ugo I; McKay, Adam R; Thalassinos, Konstantinos; Irving, James A; Haq, Imran; Nyon, Mun Peak; Christodoulou, John; Ordóñez, Adriana; Miranda, Elena; Gooptu, Bibek

    2011-01-01

    Native, metastable serpins inherently tend to undergo stabilizing conformational transitions in mechanisms of health (e.g., enzyme inhibition) and disease (serpinopathies). This intrinsic tendency is modifiable by ligand binding, thus structure-based drug design is an attractive strategy in the serpinopathies. This can be viewed as a labor-intensive approach, and historically, its intellectual attractiveness has been tempered by relatively limited success in development of drugs reaching clinical practice. However, the increasing availability of a range of powerful experimental systems and higher-throughput techniques is causing academic and early-stage industrial pharmaceutical approaches to converge. In this review, we outline the different systems and techniques that are bridging the gap between what have traditionally been considered distinct disciplines. The individual methods are not serpin-specific. Indeed, many have only recently been applied to serpins, and thus investigators in other fields may have greater experience of their use to date. However, by presenting examples from our work and that of other investigators in the serpin field, we highlight how techniques with potential for automation and scaling can be combined to address a range of context-specific challenges in targeting the serpinopathies.

  8. High-throughput screening using patient-derived tumor xenografts to predict clinical trial drug response.

    PubMed

    Gao, Hui; Korn, Joshua M; Ferretti, Stéphane; Monahan, John E; Wang, Youzhen; Singh, Mallika; Zhang, Chao; Schnell, Christian; Yang, Guizhi; Zhang, Yun; Balbin, O Alejandro; Barbe, Stéphanie; Cai, Hongbo; Casey, Fergal; Chatterjee, Susmita; Chiang, Derek Y; Chuai, Shannon; Cogan, Shawn M; Collins, Scott D; Dammassa, Ernesta; Ebel, Nicolas; Embry, Millicent; Green, John; Kauffmann, Audrey; Kowal, Colleen; Leary, Rebecca J; Lehar, Joseph; Liang, Ying; Loo, Alice; Lorenzana, Edward; Robert McDonald, E; McLaughlin, Margaret E; Merkin, Jason; Meyer, Ronald; Naylor, Tara L; Patawaran, Montesa; Reddy, Anupama; Röelli, Claudia; Ruddy, David A; Salangsang, Fernando; Santacroce, Francesca; Singh, Angad P; Tang, Yan; Tinetto, Walter; Tobler, Sonja; Velazquez, Roberto; Venkatesan, Kavitha; Von Arx, Fabian; Wang, Hui Qin; Wang, Zongyao; Wiesmann, Marion; Wyss, Daniel; Xu, Fiona; Bitter, Hans; Atadja, Peter; Lees, Emma; Hofmann, Francesco; Li, En; Keen, Nicholas; Cozens, Robert; Jensen, Michael Rugaard; Pryer, Nancy K; Williams, Juliet A; Sellers, William R

    2015-11-01

    Profiling candidate therapeutics with limited cancer models during preclinical development hinders predictions of clinical efficacy and identifying factors that underlie heterogeneous patient responses for patient-selection strategies. We established ∼1,000 patient-derived tumor xenograft models (PDXs) with a diverse set of driver mutations. With these PDXs, we performed in vivo compound screens using a 1 × 1 × 1 experimental design (PDX clinical trial or PCT) to assess the population responses to 62 treatments across six indications. We demonstrate both the reproducibility and the clinical translatability of this approach by identifying associations between a genotype and drug response, and established mechanisms of resistance. In addition, our results suggest that PCTs may represent a more accurate approach than cell line models for assessing the clinical potential of some therapeutic modalities. We therefore propose that this experimental paradigm could potentially improve preclinical evaluation of treatment modalities and enhance our ability to predict clinical trial responses.

  9. Superhydrophobic chips for cell spheroids high-throughput generation and drug screening.

    PubMed

    Oliveira, Mariana B; Neto, Ana I; Correia, Clara R; Rial-Hermida, Maria Isabel; Alvarez-Lorenzo, Carmen; Mano, João F

    2014-06-25

    We suggest the use of biomimetic superhydrophobic patterned chips produced by a benchtop methodology as low-cost and waste-free platforms for the production of arrays of cell spheroids/microtissues by the hanging drop methodology. Cell spheroids have a wide range of applications in biotechnology fields. For drug screening, they allow studying 3D models in structures resembling real living tissues/tumors. In tissue engineering, they are suggested as building blocks of bottom-up fabricated tissues. We used the wettability contrast of the chips to fix cell suspension droplets in the wettable regions and evaluated on-chip drug screening in 3D environment. Cell suspensions were patterned in the wettable spots by three distinct methods: (1) by pipetting the cell suspension directly in each individual spot, (2) by the continuous dragging of a cell suspension on the chip, and (3) by dipping the whole chip in a cell suspension. These methods allowed working with distinct throughputs and degrees of precision. The platforms were robust, and we were able to have static or dynamic environments in each droplet. The access to cell culture media for exchange or addition/removal of components was versatile and opened the possibility of using each spot of the chip as a mini-bioreactor. The platforms' design allowed for samples visualization and high-content image-based analysis on-chip. The combinatorial analysis capability of this technology was validated by following the effect of doxorubicin at different concentrations on spheroids formed using L929 and SaOs-2 cells.

  10. Long term effectiveness of antimalarial drugs in rheumatic diseases

    PubMed Central

    Avina-Zubieta, J; Galindo-Rodriguez, G.; Newman, S.; Suarez-Almazor, M.; Russell, A.

    1998-01-01

    OBJECTIVE—The purpose of this study was to compare the long term effectiveness between chloroquine (CQ) and hydroxychloroquine (HCQ).
METHODS—Medical charts of all patients seen by eight rheumatologists practising in two tertiary care centres and starting antimalarial treatment between January 1985 and December 1993 were reviewed. Patient characteristics, disease, and treatment information were collected. The main outcome measures were the cause of and the time to the discontinuation of antimalarial drugs resulting from all causes, principally toxicity or inefficacy, or both. Bivariate analysis including t tests and χ2 tests were used to assess differences between means and proportions respectively. Survival curves were evaluated using the Kaplan-Meier method. Multivariate analysis (Cox regression) was used to adjust for potential confounders.
RESULTS—After all medical records were reviewed, 1042 eligible cases were identified. From these, 940 (90%) had usable information and they represent the cohort. Five hundred and fifty eight had rheumatoid arthritis, 178 had systemic lupus erythematosus, 127 had palindromic arthritis, and 77 had other diagnoses. Fifty seven per cent of the patients received CQ and 43% HCQ. The proportion of patients with side effects taking HCQ and CQ was 15% and 28% respectively (p=0.001). Using Cox regression model to adjust for age at the onset of antimalarial treatment, physician differences, sex, disease type, disease duration before treatment, and rank selection, there were no differences in the hazard ratio (HR) for overall discontinuations between CQ and HCQ. While the HR for discontinuations because of toxicity was lower for HCQ (HR= 0.6, 95% CI 0.4, 0.9), the HR for discontinuations because of inefficacy was significantly higher for HCQ (HR= 1.4, 95% CI 1.1, 1.9).
CONCLUSIONS—After adjusting for time and several confounders HCQ was less toxic but less effective than CQ. Only one case of probable

  11. A critical evaluation of in vitro cell culture models for high-throughput drug screening and toxicity.

    PubMed

    Astashkina, Anna; Mann, Brenda; Grainger, David W

    2012-04-01

    Drug candidate and toxicity screening processes currently rely on results from early-stage in vitro cell-based assays expected to faithfully represent essential aspects of in vivo pharmacology and toxicology. Several in vitro designs are optimized for high throughput to benefit screening efficiencies, allowing the entire libraries of potential pharmacologically relevant or possible toxin molecules to be screened for different types of cell signals relevant to tissue damage or to therapeutic goals. Creative approaches to multiplexed cell-based assay designs that select specific cell types, signaling pathways and reporters are routine. However, substantial percentages of new chemical and biological entities (NCEs/NBEs) that fail late-stage human drug testing, or receive regulatory "black box" warnings, or that are removed from the market for safety reasons after regulatory approvals all provide strong evidence that in vitro cell-based assays and subsequent preclinical in vivo studies do not yet provide sufficient pharmacological and toxicity data or reliable predictive capacity for understanding drug candidate performance in vivo. Without a reliable translational assay tool kit for pharmacology and toxicology, the drug development process is costly and inefficient in taking initial in vitro cell-based screens to in vivo testing and subsequent clinical approvals. Commonly employed methods of in vitro testing, including dissociated, organotypic, organ/explant, and 3-D cultures, are reviewed here with specific focus on retaining cell and molecular interactions and physiological parameters that determine cell phenotypes and their corresponding responses to bioactive agents. Distinct advantages and performance challenges for these models pertinent to cell-based assay and their predictive capabilities required for accurate correlations to in vivo mechanisms of drug toxicity are compared. PMID:22252140

  12. Quantitative High-Throughput Profiling of Environmental Chemicals and Drugs that Modulate Farnesoid X Receptor

    PubMed Central

    Hsu, Chia-Wen; Zhao, Jinghua; Huang, Ruili; Hsieh, Jui-Hua; Hamm, Jon; Chang, Xiaoqing; Houck, Keith; Xia, Menghang

    2014-01-01

    The farnesoid X receptor (FXR) regulates the homeostasis of bile acids, lipids, and glucose. Because endogenous chemicals bind and activate FXR, it is important to examine which xenobiotic compounds would disrupt normal receptor function. We used a cell-based human FXR β-lactamase (Bla) reporter gene assay to profile the Tox21 10K compound collection of environmental chemicals and drugs. Structure-activity relationships of FXR-active compounds revealed by this screening were then compared against the androgen receptor, estrogen receptor α, peroxisome proliferator-activated receptors δ and γ, and the vitamin D receptor. We identified several FXR-active structural classes including anthracyclines, benzimidazoles, dihydropyridines, pyrethroids, retinoic acids, and vinca alkaloids. Microtubule inhibitors potently decreased FXR reporter gene activity. Pyrethroids specifically antagonized FXR transactivation. Anthracyclines affected reporter activity in all tested assays, suggesting non-specific activity. These results provide important information to prioritize chemicals for further investigation, and suggest possible modes of action of compounds in FXR signaling. PMID:25257666

  13. Toxic effects of antimalarial drugs in Paramecium: role of calcium channels.

    PubMed

    Nori, V S; Barry, S R

    1997-05-01

    The antimalarial drugs, quinacrine, quinine and mefloquine, as well as the structurally-similar compound, W-7, inhibit calcium-dependent backward swimming and calcium currents in Paramecium calkinsi. These drugs are also toxic to paramecia at high concentrations. Therefore, one site of toxic action of the drugs may be the calcium channel. To test this hypothesis, the toxicity of the antimalarials and W-7 was compared in paramecia with and without calcium channels. Since calcium channels are located on the cilia, calcium channels were removed from the paramecia by deciliating the cells. Deciliated cells were found to be less susceptible to the lethal effects of the antimalarials and W-7 than their ciliated counterparts. Moreover, Pawns, mutants of P. tetraurelia that possess cilia but lack functional calcium channels, were also less susceptible to the antimalarials than wild-type cells. Thus, calcium channels may be one site of toxic action of the antimalarial drugs in paramecia and perhaps in other protists.

  14. High-throughput protein crystallization.

    PubMed

    Stevens, R C

    2000-10-01

    The combinatorial chemistry industry has made major advances in the handling and mixing of small volumes, and in the development of robust liquid-handling systems. In addition, developments have been made in the area of material handling for the high-throughput drug screening and combinatorial chemistry fields. Lastly, improvements in beamline optics at synchrotron sources have enabled the use of flash-frozen micron-sized (10-50 microm) crystals. The combination of these and other recent advances will make high-throughput protein crystallography possible. Further advances in high-throughput methods of protein crystallography will require application of the above developments and the accumulation of success/failure data in a more systematic manner. Major changes in crystallography technology will emerge based on the data collected by first-generation high-throughput systems.

  15. Multilayered, Hyaluronic Acid-Based Hydrogel Formulations Suitable for Automated 3D High Throughput Drug Screening of Cancer-Stromal Cell Cocultures.

    PubMed

    Engel, Brian J; Constantinou, Pamela E; Sablatura, Lindsey K; Doty, Nathaniel J; Carson, Daniel D; Farach-Carson, Mary C; Harrington, Daniel A; Zarembinski, Thomas I

    2015-08-01

    Validation of a high-throughput compatible 3D hyaluronic acid hydrogel coculture of cancer cells with stromal cells. The multilayered hyaluronic acid hydrogels improve drug screening predictability as evaluated with a panel of clinically relevant chemotherapeutics in both prostate and endometrial cancer cell lines compared to 2D culture. PMID:26059746

  16. A high-throughput lab-on-a-chip interface for zebrafish embryo tests in drug discovery and ecotoxicology

    NASA Astrophysics Data System (ADS)

    Zhu, Feng; Akagi, Jin; Hall, Chris J.; Crosier, Kathryn E.; Crosier, Philip S.; Delaage, Pierre; Wlodkowic, Donald

    2013-12-01

    Drug discovery screenings performed on zebrafish embryos mirror with a high level of accuracy. The tests usually performed on mammalian animal models, and the fish embryo toxicity assay (FET) is one of the most promising alternative approaches to acute ecotoxicity testing with adult fish. Notwithstanding this, conventional methods utilising 96-well microtiter plates and manual dispensing of fish embryos are very time-consuming. They rely on laborious and iterative manual pipetting that is a main source of analytical errors and low throughput. In this work, we present development of a miniaturised and high-throughput Lab-on-a-Chip (LOC) platform for automation of FET assays. The 3D high-density LOC array was fabricated in poly-methyl methacrylate (PMMA) transparent thermoplastic using infrared laser micromachining while the off-chip interfaces were fabricated using additive manufacturing processes (FDM and SLA). The system's design facilitates rapid loading and immobilization of a large number of embryos in predefined clusters of traps during continuous microperfusion of drugs/toxins. It has been conceptually designed to seamlessly interface with both upright and inverted fluorescent imaging systems and also to directly interface with conventional microtiter plate readers that accept 96-well plates. We also present proof-of-concept interfacing with a high-speed imaging cytometer Plate RUNNER HD® capable of multispectral image acquisition with resolution of up to 8192 x 8192 pixels and depth of field of about 40 μm. Furthermore, we developed a miniaturized and self-contained analytical device interfaced with a miniaturized USB microscope. This system modification is capable of performing rapid imaging of multiple embryos at a low resolution for drug toxicity analysis.

  17. Novel Arenavirus Entry Inhibitors Discovered by Using a Minigenome Rescue System for High-Throughput Drug Screening

    PubMed Central

    Rathbun, Jessica Y.; Droniou, Magali E.; Damoiseaux, Robert; Haworth, Kevin G.; Henley, Jill E.; Exline, Colin M.; Choe, Hyeryun

    2015-01-01

    ABSTRACT Certain members of the Arenaviridae family are category A agents capable of causing severe hemorrhagic fevers in humans. Specific antiviral treatments do not exist, and the only commonly used drug, ribavirin, has limited efficacy and can cause severe side effects. The discovery and development of new antivirals are inhibited by the biohazardous nature of the viruses, making them a relatively poorly understood group of human pathogens. We therefore adapted a reverse-genetics minigenome (MG) rescue system based on Junin virus, the causative agent of Argentine hemorrhagic fever, for high-throughput screening (HTS). The MG rescue system recapitulates all stages of the virus life cycle and enables screening of small-molecule libraries under biosafety containment level 2 (BSL2) conditions. The HTS resulted in the identification of four candidate compounds with potent activity against a broad panel of arenaviruses, three of which were completely novel. The target for all 4 compounds was the stage of viral entry, which positions the compounds as potentially important leads for future development. IMPORTANCE The arenavirus family includes several members that are highly pathogenic, causing acute viral hemorrhagic fevers with high mortality rates. No specific effective treatments exist, and although a vaccine is available for Junin virus, the causative agent of Argentine hemorrhagic fever, it is licensed for use only in areas where Argentine hemorrhagic fever is endemic. For these reasons, it is important to identify specific compounds that could be developed as antivirals against these deadly viruses. PMID:26041296

  18. A quantitative high throughput assay for identifying gametocytocidal compounds.

    PubMed

    Tanaka, Takeshi Q; Dehdashti, Seameen J; Nguyen, Dac-Trung; McKew, John C; Zheng, Wei; Williamson, Kim C

    2013-03-01

    Current antimalarial drug treatment does not effectively kill mature Plasmodium falciparum gametocytes, the parasite stage responsible for malaria transmission from human to human via a mosquito. Consequently, following standard therapy malaria can still be transmitted for over a week after the clearance of asexual parasites. A new generation of malaria drugs with gametocytocidal properties, or a gametocytocidal drug that could be used in combinational therapy with currently available antimalarials, is needed to control the spread of the disease and facilitate eradication efforts. We have developed a 1536-well gametocyte viability assay for the high throughput screening of large compound collections to identify novel compounds with gametocytocidal activity. The signal-to-basal ratio and Z'-factor for this assay were 3.2-fold and 0.68, respectively. The IC(50) value of epoxomicin, the positive control compound, was 1.42±0.09 nM that is comparable to previously reported values. This miniaturized assay significantly reduces the number of gametocytes required for the AlamarBlue viability assay, and enables high throughput screening for lead discovery efforts. Additionally, the screen does not require a specialized parasite line, gametocytes from any strain, including field isolates, can be tested. A pilot screen utilizing the commercially available LOPAC library, consisting of 1280 known compounds, revealed two selective gametocytocidal compounds having 54- and 7.8-fold gametocytocidal selectivity in comparison to their cell cytotoxicity effect against the mammalian SH-SY5Y cell line.

  19. A Quantitative High Throughput Assay for Identifying Gametocytocidal Compounds

    PubMed Central

    Tanaka, Takeshi Q.; Dehdashti, Seameen J.; Nguyen, Dac-Trung; McKew, John C.; Zheng, Wei; Williamson, Kim C.

    2013-01-01

    Current antimalarial drug treatment does not effectively kill mature Plasmodium falciparum gametocytes, the parasite stage responsible for malaria transmission from human to human via a mosquito. Consequently, following standard therapy malaria can still be transmitted for over a week after the clearance of asexual parasites. A new generation of malaria drugs with gametocytocidal properties, or a gametocytocidal drug that could be used in combinational therapy with currently available antimalarials, is needed to control the spread of the disease and facilitate eradication efforts. We have developed a 1,536-well gametocyte viability assay for the high throughput screening of large compound collections to identify novel compounds with gametocytocidal activity. The signal-to-basal ratio and Z′-factor for this assay were 3.2-fold and 0.68, respectively. The IC50 value of epoxomicin, the positive control compound, was 1.42 ± 0.09 nM that is comparable to previously reported values. This miniaturized assay significantly reduces the number of gametocytes required for the alamarBlue viability assay, and enables high throughput screening for lead discovery efforts. Additionally, the screen does not require a specialized parasite line, gametocytes from any strain, including field isolates, can be tested. A pilot screen utilizing the commercially available LOPAC library, consisting of 1,280 known compounds, revealed two selective gametocytocidal compounds having 54 and 7.8-fold gametocytocidal selectivity in comparison to their cell cytotoxicity effect against the mammalian SH-SY5Y cell line. PMID:23454872

  20. High-throughput analysis of genome-wide receptor tyrosine kinase expression in human cancers identifies potential novel drug targets.

    PubMed

    Müller-Tidow, Carsten; Schwäble, Joachim; Steffen, Björn; Tidow, Nicola; Brandt, Burkhardt; Becker, Kerstin; Schulze-Bahr, Eric; Halfter, Hartmut; Vogt, Ulf; Metzger, Ralf; Schneider, Paul M; Büchner, Thomas; Brandts, Christian; Berdel, Wolfgang E; Serve, Hubert

    2004-02-15

    Novel high-throughput analyses in molecular biology allow sensitive and rapid identification of disease-related genes and drug targets. We have used quantitative real-time reverse transcription-PCR reactions (n = 23000) to analyze expression of all human receptor tyrosine kinases (n = 56) in malignant tumors (n = 313) of different origins and normal control samples (n = 58). The different tumor types expressed very different numbers of receptor tyrosine kinases: whereas brain tumors and testicular cancer expressed 50 receptor tyrosine kinases, acute myeloid leukemia (AML) samples expressed only 20 different ones. Specimens of similar tumor origin exhibited characteristic receptor tyrosine kinase expression patterns and were grouped together in hierarchical cluster analyses. When we focused on specific tumor entities, receptor tyrosine kinases were identified that were disease and/or stage specific. Leukemic blasts from AML bone marrow samples differed significantly in receptor tyrosine kinase expression compared with normal bone marrow and purified CD34+ cells. Among the differentially expressed receptor tyrosine kinases, we found FLT3, c-kit, CSF1 receptor, EPHB6, leukocyte tyrosine kinase, and ptk7 to be highly overexpressed in AML samples. Whereas expression changes of some of these were associated with altered differentiation patterns (e.g., CSF1 receptor), others, such as FLT3, were genuinely overexpressed in leukemic blasts. These data and the associated database (http://medweb.uni-muenster.de/institute/meda/research/) provide a comprehensive view of receptor tyrosine kinase expression in human cancer. This information can assist in the definition of novel drug targets.

  1. The antimalarial drug quinine interferes with serotonin biosynthesis and action.

    PubMed

    Islahudin, Farida; Tindall, Sarah M; Mellor, Ian R; Swift, Karen; Christensen, Hans E M; Fone, Kevin C F; Pleass, Richard J; Ting, Kang-Nee; Avery, Simon V

    2014-01-01

    The major antimalarial drug quinine perturbs uptake of the essential amino acid tryptophan, and patients with low plasma tryptophan are predisposed to adverse quinine reactions; symptoms of which are similar to indications of tryptophan depletion. As tryptophan is a precursor of the neurotransmitter serotonin (5-HT), here we test the hypothesis that quinine disrupts serotonin function. Quinine inhibited serotonin-induced proliferation of yeast as well as human (SHSY5Y) cells. One possible cause of this effect is through inhibition of 5-HT receptor activation by quinine, as we observed here. Furthermore, cells exhibited marked decreases in serotonin production during incubation with quinine. By assaying activity and kinetics of the rate-limiting enzyme for serotonin biosynthesis, tryptophan hydroxylase (TPH2), we showed that quinine competitively inhibits TPH2 in the presence of the substrate tryptophan. The study shows that quinine disrupts both serotonin biosynthesis and function, giving important new insight to the action of quinine on mammalian cells.

  2. Modulation of PF10_0355 (MSPDBL2) Alters Plasmodium falciparum Response to Antimalarial Drugs

    PubMed Central

    Van Tyne, Daria; Uboldi, Alessandro D.; Healer, Julie; Cowman, Alan F.

    2013-01-01

    Malaria's ability to rapidly adapt to new drugs has allowed it to remain one of the most devastating infectious diseases of humans. Understanding and tracking the genetic basis of these adaptations are critical to the success of treatment and intervention strategies. The novel antimalarial resistance locus PF10_0355 (Pfmspdbl2) was previously associated with the parasite response to halofantrine, and functional validation confirmed that overexpression of this gene lowered parasite sensitivity to both halofantrine and the structurally related antimalarials mefloquine and lumefantrine, predominantly through copy number variation. Here we further characterize the role of Pfmspdbl2 in mediating the antimalarial drug response of Plasmodium falciparum. Knockout of Pfmspdbl2 increased parasite sensitivity to halofantrine, mefloquine, and lumefantrine but not to unrelated antimalarials, further suggesting that this gene mediates the parasite response to a specific class of antimalarial drugs. A single nucleotide polymorphism encoding a C591S mutation within Pfmspdbl2 had the strongest association with halofantrine sensitivity and showed a high derived allele frequency among Senegalese parasites. Transgenic parasites expressing the ancestral Pfmspdbl2 allele were more sensitive to halofantrine and structurally related antimalarials than were parasites expressing the derived allele, revealing an allele-specific effect on drug sensitivity in the absence of copy number effects. Finally, growth competition experiments showed that under drug pressure, parasites expressing the derived allele of Pfmspdbl2 outcompeted parasites expressing the ancestral allele within a few generations. Together, these experiments demonstrate that modulation of Pfmspdbl2 affects malaria parasite responses to antimalarial drugs. PMID:23587962

  3. Assessment of urinary excretion of antimalarial drugs in large-scale chemotherapeutic eradication projects

    PubMed Central

    Bruce-Chwatt, L. J.

    1959-01-01

    Assessment of the urinary excretion of an antimalarial drug is a useful means of checking the amount of drug administered and the regularity of intake. The author describes the various methods available for the qualitative and quantitative estimation of antimalarial drugs in urine and discusses their relative merits, with special reference to their suitability for use in the field. He points out the difficulties involved in estimating the urinary excretion of antimalarials in large-scale chemotherapeutic eradication projects and stress the importance of simplifying testing techniques as far as possible. PMID:13805135

  4. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network

    PubMed Central

    Cui, Liwang; Mharakurwa, Sungano; Ndiaye, Daouda; Rathod, Pradipsinh K.; Rosenthal, Philip J.

    2015-01-01

    Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs. PMID:26259943

  5. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network.

    PubMed

    Cui, Liwang; Mharakurwa, Sungano; Ndiaye, Daouda; Rathod, Pradipsinh K; Rosenthal, Philip J

    2015-09-01

    Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs. PMID:26259943

  6. Superinfection and the evolution of resistance to antimalarial drugs.

    PubMed

    Klein, Eili Y; Smith, David L; Laxminarayan, Ramanan; Levin, Simon

    2012-09-22

    A major issue in the control of malaria is the evolution of drug resistance. Ecological theory has demonstrated that pathogen superinfection and the resulting within-host competition influences the evolution of specific traits. Individuals infected with Plasmodium falciparum are consistently infected by multiple parasites; however, while this probably alters the dynamics of resistance evolution, there are few robust mathematical models examining this issue. We developed a general theory for modelling the evolution of resistance with host superinfection and examine: (i) the effect of transmission intensity on the rate of resistance evolution; (ii) the importance of different biological costs of resistance; and (iii) the best measure of the frequency of resistance. We find that within-host competition retards the ability and slows the rate at which drug-resistant parasites invade, particularly as the transmission rate increases. We also find that biological costs of resistance that reduce transmission are less important than reductions in the duration of drug-resistant infections. Lastly, we find that random sampling of the population for resistant parasites is likely to significantly underestimate the frequency of resistance. Considering superinfection in mathematical models of antimalarial drug resistance may thus be important for generating accurate predictions of interventions to contain resistance.

  7. Superinfection and the evolution of resistance to antimalarial drugs

    PubMed Central

    Klein, Eili Y.; Smith, David L.; Laxminarayan, Ramanan; Levin, Simon

    2012-01-01

    A major issue in the control of malaria is the evolution of drug resistance. Ecological theory has demonstrated that pathogen superinfection and the resulting within-host competition influences the evolution of specific traits. Individuals infected with Plasmodium falciparum are consistently infected by multiple parasites; however, while this probably alters the dynamics of resistance evolution, there are few robust mathematical models examining this issue. We developed a general theory for modelling the evolution of resistance with host superinfection and examine: (i) the effect of transmission intensity on the rate of resistance evolution; (ii) the importance of different biological costs of resistance; and (iii) the best measure of the frequency of resistance. We find that within-host competition retards the ability and slows the rate at which drug-resistant parasites invade, particularly as the transmission rate increases. We also find that biological costs of resistance that reduce transmission are less important than reductions in the duration of drug-resistant infections. Lastly, we find that random sampling of the population for resistant parasites is likely to significantly underestimate the frequency of resistance. Considering superinfection in mathematical models of antimalarial drug resistance may thus be important for generating accurate predictions of interventions to contain resistance. PMID:22787024

  8. High-throughput in vitro drug release and pharmacokinetic simulation as a tool for drug delivery system development: application to intravitreal ocular administration.

    PubMed

    Sarkhel, Sanjay; Ramsay, Eva; Kontturi, Leena-Stiina; Peltoniemi, Jonne; Urtti, Arto

    2014-12-30

    In vitro estimation of release kinetics from drug delivery systems is needed in formulation development. Cost-effective methods of assessment for delivery systems are needed particularly in the case of biologicals and drug administration routes that are difficult to screen in vivo (e.g. intraocular drug delivery). As a proof-of-concept, we demonstrate here a practical high-throughput methodology to investigate in vitro drug release and predict resulting drug concentrations in the eye after intravitreal administration. 96-well plate based assay aided with robotic sampling was used to study release of eight model drugs of varying physicochemical properties (dexamethasone, vancomycin, alpha-lactalbumin, lysozyme, myoglobin, albumin, lactoferrin, human IgG) from twelve alginate microsphere formulations. The amount of drug released over a period of time was assessed by photometric and fluorescence methods. In vitro drug release rates obtained were used in pharmacokinetic simulations using one-compartment model of the vitreal cavity with anatomical volume of distribution and clearance estimates based on the literature precedence. An integrated approach of drug release screening and pharmacokinetic simulations can prove to be a useful methodology in guiding formulation development for ocular delivery in animal models. In general, the methodology has the potential to be a cost-effective tool for early stage drug delivery system discovery and development.

  9. A biomimetic Schlemm's canal inner wall: A model to study outflow physiology, glaucoma pathology and high-throughput drug screening.

    PubMed

    Dautriche, Cula N; Szymanski, Dennis; Kerr, Matthew; Torrejon, Karen Y; Bergkvist, Magnus; Xie, Yubing; Danias, John; Stamer, W D; Sharfstein, Susan T

    2015-10-01

    Glaucoma is a disease that damages the optic nerve, frequently leading to blindness. Elevated intraocular pressure (IOP) is the only modifiable risk factor for glaucoma, which is expected to affect 80 million people by 2020, causing bilateral blindness in over 10 million individuals. Because pathological changes to Schlemm's canal (SC) may account for significant resistance to outflow, there is considerable interest in characterizing and evaluating the Schlemm's canal as a target for glaucoma therapeutics. In conventional, two-dimensional culture, human Schlemm's canal (HSC) cells lose spatial, mechanical and biochemical cues, resulting in altered gene expression and cell signaling than observed in vivo, compromising the clinical relevance of data obtained from such systems. Here, we report, for the first time, that 3D culture of HSC cells on microfabricated scaffolds with defined physical and biochemical cues, rescued expression of key HSC markers, VE-cadherin and PECAM1, and mediated pore formation, crucial for the Schlemm's canal regulation of IOP. We demonstrated that following treatment with the glaucopathogenic agent, TGF-β2, HSC cells undergo an endothelial-mesenchymal transition, which together with the increase in extracellular matrix (ECM) proteins might account for the decrease in outflow facility observed in patients with high TGF-β2 levels in their aqueous humor. We also demonstrated that unlike 2D cultures, 3D cultures of HSC cells are amenable to gene transfer. Thus, our data imply that 3D culture of HSC cells may be used as a platform to advance our understanding of HSC physiology and pathology and as a model for high-throughput drug and gene screening.

  10. A biomimetic Schlemm's canal inner wall: a model to study outflow physiology, glaucoma pathology and high-throughput drug screening

    PubMed Central

    Dautriche, Cula N.; Szymanski, Dennis; Kerr, Matthew; Torrejon, Karen Y.; Bergkvist, Magnus; Xie, Yubing; Danias, John; Stamer, W.D.; Sharfstein, Susan T.

    2015-01-01

    Glaucoma is a disease that damages the optic nerve, frequently leading to blindness. Elevated intraocular pressure (IOP) is the only modifiable risk factor for glaucoma, which is expected to affect 80 million people by 2020, causing bilateral blindness in over 10 million individuals. Because pathological changes to Schlemm's canal (SC) may account for significant resistance to outflow, there is considerable interest in characterizing and evaluating the Schlemm's canal as a target for glaucoma therapeutics. In conventional, two-dimensional culture, human Schlemm's canal (HSC) cells lose spatial, mechanical and biochemical cues, resulting in altered gene expression and cell signaling than observed in vivo, compromising the clinical relevance of data obtained from such systems. Here, we report, for the first time, that 3D culture of HSC cells on microfabricated scaffolds with defined physical and biochemical cues, rescued expression of key HSC markers, VE-cadherin and PECAM1, and mediated pore formation, crucial for the Schlemm's canal regulation of IOP. We demonstrated that following treatment with the glaucopathogenic agent, TGF-β2, HSC cells undergo an endothelial-mesenchymal transition, which together with the increase in extracellular matrix (ECM) proteins might account for the decrease in outflow facility observed in patients with high TGF-β2 levels in their aqueous humor. We also demonstrated that unlike 2D cultures, 3D cultures of HSC cells are amenable to gene transfer. Thus, our data imply that 3D culture of HSC cells may be used as a platform to advance our understanding of HSC physiology and pathology and as a model for high-throughput drug and gene screening. PMID:26142779

  11. Targeting Plasmodium Metabolism to Improve Antimalarial Drug Design.

    PubMed

    Avitia-Domínguez, Claudia; Sierra-Campos, Erick; Betancourt-Conde, Irene; Aguirre-Raudry, Miriam; Vázquez-Raygoza, Alejandra; Luevano-De la Cruz, Artemisa; Favela-Candia, Alejandro; Sarabia-Sanchez, Marie; Ríos-Soto, Lluvia; Méndez-Hernández, Edna; Cisneros-Martínez, Jorge; Palacio-Gastélum, Marcelo Gómez; Valdez-Solana, Mónica; Hernández-Rivera, Jessica; De Lira-Sánchez, Jaime; Campos-Almazán, Mara; Téllez-Valencia, Alfredo

    2016-01-01

    Malaria is one of the main infectious diseases in tropical developing countries and represents high morbidity and mortality rates nowadays. The principal etiological agent P. falciparum is transmitted through the bite of the female Anopheles mosquito. The issue has escalated due to the emergence of resistant strains to most of the antimalarials used for the treatment including Chloroquine, Sulfadoxine-Pyrimethamine, and recently Artemisinin derivatives, which has led to diminished effectiveness and by consequence increased the severity of epidemic outbreaks. Due to the lack of effective compounds to treat these drug-resistant strains, the discovery or development of novel anti-malaria drugs is important. In this context, one strategy has been to find inhibitors of enzymes, which play an important role for parasite survival. Today, promising results have been obtained in this regard, involving the entire P. falciparum metabolism. These inhibitors could serve as leads in the search of a new chemotherapy against malaria. This review focuses on the achievements in recent years with regard to inhibition of enzymes used as targets for drug design against malaria. PMID:26983887

  12. A high-throughput chemical screen with FDA approved drugs reveals that the antihypertensive drug Spironolactone impairs cancer cell survival by inhibiting homology directed repair

    PubMed Central

    Shahar, Or David; Kalousi, Alkmini; Eini, Lital; Fisher, Benoit; Weiss, Amelie; Darr, Jonatan; Mazina, Olga; Bramson, Shay; Kupiec, Martin; Eden, Amir; Meshorer, Eran; Mazin, Alexander V.; Brino, Laurent; Goldberg, Michal; Soutoglou, Evi

    2014-01-01

    DNA double-strand breaks (DSBs) are the most severe type of DNA damage. DSBs are repaired by non-homologous end-joining or homology directed repair (HDR). Identifying novel small molecules that affect HDR is of great importance both for research use and therapy. Molecules that elevate HDR may improve gene targeting whereas inhibiting molecules can be used for chemotherapy, since some of the cancers are more sensitive to repair impairment. Here, we performed a high-throughput chemical screen for FDA approved drugs, which affect HDR in cancer cells. We found that HDR frequencies are increased by retinoic acid and Idoxuridine and reduced by the antihypertensive drug Spironolactone. We further revealed that Spironolactone impairs Rad51 foci formation, sensitizes cancer cells to DNA damaging agents, to Poly (ADP-ribose) polymerase (PARP) inhibitors and cross-linking agents and inhibits tumor growth in xenografts, in mice. This study suggests Spironolactone as a new candidate for chemotherapy. PMID:24682826

  13. A high-throughput chemical screen with FDA approved drugs reveals that the antihypertensive drug Spironolactone impairs cancer cell survival by inhibiting homology directed repair.

    PubMed

    Shahar, Or David; Kalousi, Alkmini; Eini, Lital; Fisher, Benoit; Weiss, Amelie; Darr, Jonatan; Mazina, Olga; Bramson, Shay; Kupiec, Martin; Eden, Amir; Meshorer, Eran; Mazin, Alexander V; Brino, Laurent; Goldberg, Michal; Soutoglou, Evi

    2014-05-01

    DNA double-strand breaks (DSBs) are the most severe type of DNA damage. DSBs are repaired by non-homologous end-joining or homology directed repair (HDR). Identifying novel small molecules that affect HDR is of great importance both for research use and therapy. Molecules that elevate HDR may improve gene targeting whereas inhibiting molecules can be used for chemotherapy, since some of the cancers are more sensitive to repair impairment. Here, we performed a high-throughput chemical screen for FDA approved drugs, which affect HDR in cancer cells. We found that HDR frequencies are increased by retinoic acid and Idoxuridine and reduced by the antihypertensive drug Spironolactone. We further revealed that Spironolactone impairs Rad51 foci formation, sensitizes cancer cells to DNA damaging agents, to Poly (ADP-ribose) polymerase (PARP) inhibitors and cross-linking agents and inhibits tumor growth in xenografts, in mice. This study suggests Spironolactone as a new candidate for chemotherapy.

  14. Next-Generation Antimalarial Drugs: Hybrid Molecules as a New Strategy in Drug Design

    PubMed Central

    Muregi, Francis W; Ishih, Akira

    2010-01-01

    Malaria is a disease that affects nearly 40% of the global population, and chemotherapy remains the mainstay of its control strategy. The global malaria situation is increasingly being exacerbated by the emergence of drug resistance to most of the available antimalarials, necessitating search for novel drugs. A recent rational approach of antimalarial drug design characterized as “covalent bitherapy” involves linking two molecules with individual intrinsic activity into a single agent, thus packaging dual-activity into a single hybrid molecule. Current research in this field seems to endorse hybrid molecules as the next-generation antimalarial drugs. If the selective toxicity of hybrid prodrugs can be demonstrated in vivo with good bioavailability at the target site in the parasite, it would offer various advantages including dosage compliance, minimized toxicity, ability to design better drug combinations, and cheaper preclinical evaluation while achieving the ultimate object of delaying or circumventing the development of resistance. This review is focused on several hybrid molecules that have been developed, with particular emphasis on those deemed to have high potential for development for clinical use. Drug Dev Res 71: 20–32, 2010. © 2009 Wiley-Liss, Inc. PMID:21399701

  15. Perspective for the production of antimalarial drugs in Brazil.

    PubMed

    Gilbert, B

    1992-01-01

    There appears to be no chemical manufacture of antimalarial drugs in Brazil. Technology at the laboratory process level has been developed for chloroquine, mefloquine, pyrimethamine and cycloguanil, but not perfected nor scaled-up, largely for economic reasons and market uncertainty. Development of primaquine has been contracted but it will run into the same difficulty. Manufacturing capacity for sulfadoxine was registered in the SDI by Roche. A project to produce artemisinine and its derivatives is under way at UNICAMP-CPQBA but is hampered by low content in the plant. Proguanil could be produced easily, but apparently no attempt has been made to do so. Quinine is imported on a large scale mostly for soft-drink production. Since malarial treatment falls largely within the responsibility of the Government health authorities, manufacture of drugs in Brazil will depend on an assured medium-term purchase order made to a potential local manufacturer, since competition in the world market is scarcely viable at the present moment.

  16. A concentration gradient generator on a paper-based microfluidic chip coupled with cell culture microarray for high-throughput drug screening.

    PubMed

    Hong, Bo; Xue, Peng; Wu, Yafeng; Bao, Jingnan; Chuah, Yon Jin; Kang, Yuejun

    2016-02-01

    Inspired by the paper platforms for 3-D cell culture, a paper-based microfluidic device containing drug concentration gradient was designed and constructed for investigating cell response to drugs based on high throughput analysis. This drug gradient generator was applied to generate concentration gradients of doxorubicin (DOX) as the model drug. HeLa cells encapsulated in collagen hydrogel were incubated in the device reservoirs to evaluate the cell viability based on the controlled release of DOX spatially. It was demonstrated that drug diffusion through the paper fibers created a gradient of drug concentration, which influenced cell viability. This drug screening platform has a great opportunity to be applied for drug discovery and diagnostic studies with simultaneous and parallel tests of drugs under various gradient concentrations. PMID:26864970

  17. A concentration gradient generator on a paper-based microfluidic chip coupled with cell culture microarray for high-throughput drug screening.

    PubMed

    Hong, Bo; Xue, Peng; Wu, Yafeng; Bao, Jingnan; Chuah, Yon Jin; Kang, Yuejun

    2016-02-01

    Inspired by the paper platforms for 3-D cell culture, a paper-based microfluidic device containing drug concentration gradient was designed and constructed for investigating cell response to drugs based on high throughput analysis. This drug gradient generator was applied to generate concentration gradients of doxorubicin (DOX) as the model drug. HeLa cells encapsulated in collagen hydrogel were incubated in the device reservoirs to evaluate the cell viability based on the controlled release of DOX spatially. It was demonstrated that drug diffusion through the paper fibers created a gradient of drug concentration, which influenced cell viability. This drug screening platform has a great opportunity to be applied for drug discovery and diagnostic studies with simultaneous and parallel tests of drugs under various gradient concentrations.

  18. Bioluminescent Mycobacterium aurum expressing firefly luciferase for rapid and high throughput screening of antimycobacterial drugs in vitro and in infected macrophages.

    PubMed

    Deb, D K; Srivastava, K K; Srivastava, R; Srivastava, B S

    2000-12-20

    The slow growth and highly infectious nature of Mycobacterium tuberculosis is a limiting factor in its use as test organism in high throughput screening for inhibitory compounds. To overcome these problems, use of surrogate strains and reporter genes have been considered. In this study, we have investigated the application of a fast growing nonpathogenic M. aurum expressing firefly luciferase in rapid screening of antituberculosis compounds in vitro and in infected macrophages using bioluminescence assay. The assay is based on luminescence determination using luciferin as substrate. Inhibition of bioluminescence was obtained with frontline antimycobacterial drugs like streptomycin, rifampicin, isoniazid, ethambutol, ofloxacin, and sparfloxacin at their reported MICs. Inhibition could be observed as early as 2 h in vitro and within 24 h in infected macrophages. The system can reliably be used in high throughput screening.

  19. High-Throughput Melanin-Binding Affinity and In Silico Methods to Aid in the Prediction of Drug Exposure in Ocular Tissue.

    PubMed

    Reilly, John; Williams, Sarah L; Forster, Cornelia J; Kansara, Viral; End, Peter; Serrano-Wu, Michael H

    2015-12-01

    Drugs possessing the ability to bind to melanin-rich tissue, such as the eye, are linked with higher ocular exposure, and therefore have the potential to affect the efficacy and safety profiles of therapeutics. A high-throughput melanin chromatographic affinity assay has been developed and validated, which has allowed the rapid melanin affinity assessment for a large number of compounds. Melanin affinity of compounds can be quickly assigned as low, medium, or high melanin binders. A high-throughput chromatographic method has been developed and fully validated to assess melanin affinity of pharmaceuticals and has been useful in predicting ocular tissue distribution in vivo studies. The high-throughput experimental approach has also allowed for a specific training set of 263 molecules for a quantitative structure-affinity relationships (QSAR) method to be developed, which has also been shown to be a predictor of ocular tissue exposure. Previous studies have reported the development of in silico QSAR models based on training sets of relatively small and mostly similar compounds; this model covers a broader range of melanin-binding affinities than what has been previously published and identified several physiochemical descriptors to be considered in the design of compounds where melanin-binding modulation is desired.

  20. High throughput screening informatics.

    PubMed

    Ling, Xuefeng Bruce

    2008-03-01

    High throughput screening (HTS), an industrial effort to leverage developments in the areas of modern robotics, data analysis and control software, liquid handling devices, and sensitive detectors, has played a pivotal role in the drug discovery process, allowing researchers to efficiently screen millions of compounds to identify tractable small molecule modulators of a given biological process or disease state and advance them into high quality leads. As HTS throughput has significantly increased the volume, complexity, and information content of datasets, lead discovery research demands a clear corporate strategy for scientific computing and subsequent establishment of robust enterprise-wide (usually global) informatics platforms, which enable complicated HTS work flows, facilitate HTS data mining, and drive effective decision-making. The purpose of this review is, from the data analysis and handling perspective, to examine key elements in HTS operations and some essential data-related activities supporting or interfacing the screening process, and outline properties that various enabling software should have. Additionally, some general advice for corporate managers with system procurement responsibilities is offered.

  1. A review of LC-MS techniques and high-throughput approaches used to investigate drug metabolism by cytochrome P450s.

    PubMed

    Youdim, Kuresh A; Saunders, Kenneth C

    2010-05-15

    One of the major challenges facing the pharmaceutical industry today is finding new ways to increase productivity, decrease costs whilst still ultimately developing new therapies that enhance human health. To help address these challenges the utilisation of analytical technologies and high-throughput automated platforms has been employed; in order to perform more experiments in a shorter time frame with increased data quality. One of the main in vitro techniques to assess new chemical entities in a discovery setting has been the use of recombinant liver enzymes, microsomes and hepatocytes. These techniques can help predict in vivo metabolism, clearance and potential drug-drug interactions of these new compounds by cytochrome P450s (the major drug metabolising enzymes). This in vitro methodology has been totally transformed in recent times by the use of automated liquid handling and HPLC tandem mass spectrometry detection techniques (LC-MS/MS). This review aims looking at recent advances in the methodology used to investigate drug metabolism by cytochrome P450s; including an up to date summary of high-throughput platforms including the use of automation and LC-MS/MS to facilitate greater throughput, chromatographic resolution and data quality.

  2. High-throughput combinatorial screening identifies drugs that cooperate with ibrutinib to kill activated B-cell–like diffuse large B-cell lymphoma cells

    PubMed Central

    Mathews Griner, Lesley A.; Guha, Rajarshi; Shinn, Paul; Young, Ryan M.; Keller, Jonathan M.; Liu, Dongbo; Goldlust, Ian S.; Yasgar, Adam; McKnight, Crystal; Boxer, Matthew B.; Duveau, Damien Y.; Jiang, Jian-Kang; Michael, Sam; Mierzwa, Tim; Huang, Wenwei; Walsh, Martin J.; Mott, Bryan T.; Patel, Paresma; Leister, William; Maloney, David J.; Leclair, Christopher A.; Rai, Ganesha; Jadhav, Ajit; Peyser, Brian D.; Austin, Christopher P.; Martin, Scott E.; Simeonov, Anton; Ferrer, Marc; Staudt, Louis M.; Thomas, Craig J.

    2014-01-01

    The clinical development of drug combinations is typically achieved through trial-and-error or via insight gained through a detailed molecular understanding of dysregulated signaling pathways in a specific cancer type. Unbiased small-molecule combination (matrix) screening represents a high-throughput means to explore hundreds and even thousands of drug–drug pairs for potential investigation and translation. Here, we describe a high-throughput screening platform capable of testing compounds in pairwise matrix blocks for the rapid and systematic identification of synergistic, additive, and antagonistic drug combinations. We use this platform to define potential therapeutic combinations for the activated B-cell–like subtype (ABC) of diffuse large B-cell lymphoma (DLBCL). We identify drugs with synergy, additivity, and antagonism with the Bruton’s tyrosine kinase inhibitor ibrutinib, which targets the chronic active B-cell receptor signaling that characterizes ABC DLBCL. Ibrutinib interacted favorably with a wide range of compounds, including inhibitors of the PI3K-AKT-mammalian target of rapamycin signaling cascade, other B-cell receptor pathway inhibitors, Bcl-2 family inhibitors, and several components of chemotherapy that is the standard of care for DLBCL. PMID:24469833

  3. A new high-throughput method utilizing porous silica-based nano-composites for the determination of partition coefficients of drug candidates.

    PubMed

    Yu, Chih H; Tam, Kin; Tsang, Shik C

    2011-09-01

    We show that highly porous silica-based nanoparticles prepared via micro-emulsion and sol-gel techniques are stable colloids in aqueous solution. By incorporating a magnetic core into the porous silica nano-composite, it is found that the material can be rapidly separated (precipitated) upon exposure to an external magnetic field. Alternatively, the porous silica nanoparticles without magnetic cores can be equally separated from solution by applying a high-speed centrifugation. Using these silica-based nanostructures a new high-throughput method for the determination of partition coefficient for water/n-octanol is hereby described. First, a tiny quantity of n-octanol phase is pre-absorbed in the porous silica nano-composite colloids, which allows an establishment of interface at nano-scale between the adsorbed n-octanol with the bulk aqueous phase. Organic compounds added to the mixture can therefore undergo a rapid partition between the two phases. The concentration of drug compound in the supernatant in a small vial can be determined by UV-visible absorption spectroscopy. With the adaptation of a robotic liquid handler, a high-throughput technology for the determination of partition coefficients of drug candidates can be employed for drug screening in the industry based on these nano-separation skills. The experimental results clearly suggest that this new method can provide partition coefficient values of potential drug candidates comparable to the conventional shake-flask method but requires much shorter analytical time and lesser quantity of chemicals.

  4. Ultrafast and high-throughput mass spectrometric assay for therapeutic drug monitoring of antiretroviral drugs in pediatric HIV-1 infection applying dried blood spots

    PubMed Central

    van Kampen, Jeroen J. A.; Reedijk, Mariska L.; Scheuer, Rachel D.; Dekker, Lennard J. M.; Burger, David M.; Hartwig, Nico G.; Osterhaus, Albert D. M. E.; Luider, Theo M.; Gruters, Rob A.

    2010-01-01

    Kaletra® (Abott Laboratories) is a co-formulated medication used in the treatment of HIV-1-infected children, and it contains the two antiretroviral protease inhibitor drugs lopinavir and ritonavir. We validated two new ultrafast and high-throughput mass spectrometric assays to be used for therapeutic drug monitoring of lopinavir and ritonavir concentrations in whole blood and in plasma from HIV-1-infected children. Whole blood was blotted onto dried blood spot (DBS) collecting cards, and plasma was collected simultaneously. DBS collecting cards were extracted by an acetonitrile/water mixture while plasma samples were deproteinized with acetone. Drug concentrations were determined by matrix-assisted laser desorption/ionization-triple quadrupole tandem mass spectrometry (MALDI-QqQ-MS/MS). The application of DBS made it possible to measure lopinavir and ritonavir in whole blood in therapeutically relevant concentrations. The MALDI-QqQ-MS/MS plasma assay was successfully cross-validated with a commonly used high-performance liquid chromatography (HPLC)–ultraviolet (UV) assay for the therapeutic drug monitoring (TDM) of HIV-1-infected patients, and it showed comparable performance characteristics. Observed DBS concentrations showed as well, a good correlation between plasma concentrations obtained by MALDI-QqQ-MS/MS and those obtained by the HPLC-UV assay. Application of DBS for TDM proved to be a good alternative to the normally used plasma screening. Moreover, collection of DBS requires small amounts of whole blood which can be easily performed especially in (very) young children where collection of large whole blood amounts is often not possible. DBS is perfectly suited for TDM of HIV-1-infected children; but nevertheless, DBS can also easily be applied for TDM of patients in areas with limited or no laboratory facilities. PMID:20632164

  5. High-throughput transfection and engineering of primary cells and cultured cell lines - an invaluable tool for research as well as drug development.

    PubMed

    Müller-Hartmann, Herbert; Faust, Nicole; Kazinski, Michael; Kretzschmar, Titus

    2007-11-01

    The manipulation of eukaryotic cells by introducing nucleic acids and other substrates using chemical, physical or viral methods is one of the ground-breaking tools in the life sciences. Changes in the molecular equipment of a cell induced by introducing different molecules not only enable the dissection of signal transduction and metabolic pathways, but also allow the exploitation of engineered cells as bio-factories for the production of proteins in the processes of target research and drug development. In addition to the application of engineered cells for modern cell-based assays, medically relevant engineered cells can be used in clinical settings for adoptive immunotherapy or gene therapy. With the advent of methods exploiting RNA interference (RNAi), gene identification and functional validation in eukaryotic cells have clearly become one of the most exciting methods in life sciences during the past few years. To accelerate research and development in these areas, high-quality, high-throughput approaches (i.e., using sample formats of at least 96 wells) for cell engineering are needed with increasing demand. Recent developments, especially in the field of electroporation, now allow the efficient, high-throughput engineering of virtually any cell type, including primary cells, many of which were previously considered difficult or even impossible to transfect. Primary cells freshly isolated from native tissues are gaining more and more interest, as data obtained with these cells are considered to be of higher physiological relevance than data obtained with immortalized cell lines that have been cultured for extensive periods. In this review, the various methods for cell engineering (with focus on higher eukaryotic cells) are summarized and their impact for high-throughput applications in research and drug development is discussed.

  6. Simultaneous high-throughput determination of interaction kinetics for drugs and cyclodextrins by high performance affinity chromatography with mass spectrometry detection.

    PubMed

    Wang, Caifen; Wang, Xiaobo; Xu, Xiaonan; Liu, Botao; Xu, Xu; Sun, Lixin; Li, Haiyan; Zhang, Jiwen

    2016-02-25

    The individual determination of the apparent dissociation rate constant (kd,app) using high performance affinity chromatography (HPAC) is a tedious process requiring numerous separate tests and massive data fitting, unable to provide the apparent association rate constant (ka) and equilibrium binding constant (Ka). In this study, a HPAC with mass spectrometry detection (HPAC-MS/MS) was employed to determine the drug-cyclodextrin (CD) interaction kinetics with low sample loading quantity (<10 ng per injection for single compound) and high-throughput yield as twenty drugs determined in one injection. The kd,app measured by HPAC-MS/MS approach were 0.89 ± 0.07, 4.34 ± 0.01, 1.48 ± 0.01 and 7.77 ± 0.04 s(-1) for ketoprofen, trimethoprim, indapamide and acetaminophen, with kd,app for acetaminophen consistent with that from the HPAC method with UV detector in our previous studies. For twenty drugs with diverse structures and chemical properties, good correlationship was found between kd,app measured by single compound analysis method and high-throughput HPAC-MS/MS approach, with the correlation coefficient of 0.987 and the significance F less than 0.001. Comprehensive quantification of ka,app, kd,app and Ka values was further performed based on the measurement of kd,app by peak profiling method and Ka by the peak fitting method. And the investigation of the drug-CD interaction kinetics under different conditions indicated that the column temperature and mobile phase composition significantly affected the determination of ka,app, kd,app and Ka while also dependent on the acidity and basicity of drugs. In summary, the high-throughput HPAC-MS/MS approach has been demonstrated high efficiency in determination of the drug-CD primary interaction kinetic parameter, especially, kd,app, being proven as a novel tool in screening the right CD for the solubilization of the right drug. PMID:26851087

  7. Simultaneous high-throughput determination of interaction kinetics for drugs and cyclodextrins by high performance affinity chromatography with mass spectrometry detection.

    PubMed

    Wang, Caifen; Wang, Xiaobo; Xu, Xiaonan; Liu, Botao; Xu, Xu; Sun, Lixin; Li, Haiyan; Zhang, Jiwen

    2016-02-25

    The individual determination of the apparent dissociation rate constant (kd,app) using high performance affinity chromatography (HPAC) is a tedious process requiring numerous separate tests and massive data fitting, unable to provide the apparent association rate constant (ka) and equilibrium binding constant (Ka). In this study, a HPAC with mass spectrometry detection (HPAC-MS/MS) was employed to determine the drug-cyclodextrin (CD) interaction kinetics with low sample loading quantity (<10 ng per injection for single compound) and high-throughput yield as twenty drugs determined in one injection. The kd,app measured by HPAC-MS/MS approach were 0.89 ± 0.07, 4.34 ± 0.01, 1.48 ± 0.01 and 7.77 ± 0.04 s(-1) for ketoprofen, trimethoprim, indapamide and acetaminophen, with kd,app for acetaminophen consistent with that from the HPAC method with UV detector in our previous studies. For twenty drugs with diverse structures and chemical properties, good correlationship was found between kd,app measured by single compound analysis method and high-throughput HPAC-MS/MS approach, with the correlation coefficient of 0.987 and the significance F less than 0.001. Comprehensive quantification of ka,app, kd,app and Ka values was further performed based on the measurement of kd,app by peak profiling method and Ka by the peak fitting method. And the investigation of the drug-CD interaction kinetics under different conditions indicated that the column temperature and mobile phase composition significantly affected the determination of ka,app, kd,app and Ka while also dependent on the acidity and basicity of drugs. In summary, the high-throughput HPAC-MS/MS approach has been demonstrated high efficiency in determination of the drug-CD primary interaction kinetic parameter, especially, kd,app, being proven as a novel tool in screening the right CD for the solubilization of the right drug.

  8. A new fluorescent based screening system for high throughput screening of drugs targeting HBV-core and HBsAg interaction.

    PubMed

    Suresh, V; Krishnakumar, K A; Asha, V V

    2015-03-01

    The existing screening systems for anti-hepatitis B virus (anti-HBV) drug discovery is time-consuming mainly due to the laborious detection system it is using. A new fluorescence based screening system for high throughput anti-HBV drug discovery was created by tagging hepatitis B surface antigen (HBsAg) with monomeric red fluorescent protein and hepatitis B virus (HBV) core protein with enhanced green fluorescent protein. The two constructs were co-transfected on to Hep3B cells and the transfection was stabilized by fluorescent activated cell sorter (FACS). The fusion proteins expressed through the secretory protein pathway as evidenced by localization with ER-Tracker and tubulin tracker. The new system has given analogues results like that of conventional enzyme-linked immunosorbent assay (ELISA). Hence it can be of very high potential for large scale drug screening systems.

  9. Retinal toxicity induced by antimalarial drugs: literature review and case report.

    PubMed

    Garza-Leon, Manuel; Flores-Alvarado, Diana Elsa; Muñoz-Bravo, Juan Manuel

    2016-06-17

    Antimalarial drugs are widely used in several countries for control of rheumatologic diseases such as systemic lupus erythematosus and rheumatoid arthritis. They are still used in Mexico because of their low cost and few secondary effects, most of which are mild and reversible. Even so, at an ophthalmological level, they could produce irreversible visual damage, which is why it is important to have ophthalmological evaluation and proper follow up. We present a clinical case as an example of characteristic ophthalmological findings as well as risk factors for retinal toxicity. We then discuss guidelines for diagnosis and follow up of patients who use antimalarial drugs for the treatment of rheumatologic illnesses.

  10. A reaction-diffusion system modeling the spread of resistance to an antimalarial drug.

    PubMed

    Bacaer, Nicolas; Sokhna, Cheikh

    2005-04-01

    A mathematical model representing the difusion of resistance to an antimalarial drug is developed. Resistance can spread only when the basic reproduction number of the resistant parasites is bigger than the basic reproduction number of the sensitive parasites (which depends on the fraction of infected people treated with the antimalarial drug). Based on a linearization study and on numerical simulations, an expression for the speed at which resistance spreads is conjectured. It depends on the ratio of the two basic reproduction numbers, on a coefficient representing the difusion of mosquitoes, on the death rate of mosquitoes infected by resistant parasites, and on the recovery rate of nonimmune humans infected by resistant parasites.

  11. Retinal toxicity induced by antimalarial drugs: literature review and case report.

    PubMed

    Garza-Leon, Manuel; Flores-Alvarado, Diana Elsa; Muñoz-Bravo, Juan Manuel

    2016-01-01

    Antimalarial drugs are widely used in several countries for control of rheumatologic diseases such as systemic lupus erythematosus and rheumatoid arthritis. They are still used in Mexico because of their low cost and few secondary effects, most of which are mild and reversible. Even so, at an ophthalmological level, they could produce irreversible visual damage, which is why it is important to have ophthalmological evaluation and proper follow up. We present a clinical case as an example of characteristic ophthalmological findings as well as risk factors for retinal toxicity. We then discuss guidelines for diagnosis and follow up of patients who use antimalarial drugs for the treatment of rheumatologic illnesses. PMID:27391903

  12. Quantitative RT-PCR assay for high-throughput screening (HTS) of drugs against the growth of Cryptosporidium parvum in vitro

    PubMed Central

    Zhang, Haili; Zhu, Guan

    2015-01-01

    Our laboratory has previously developed a qRT-PCR assay to assess drug efficacy on the growth of Cryptosporidium parvum in vitro by detecting the levels of parasite 18S rRNA. This approach displayed up to four orders of magnitude of linear dynamic range and was much less labor-intensive than the traditional microscopic methods. However, conventional qRT-PCR protocol is not very amendable to high-throughput analysis when total RNA needs to be purified by lengthy, multi-step procedures. Recently, several commercial reagents are available for preparing cell lysates that could be directly used in downstream qRT-PCR analysis (e.g., Ambion Cell-to-cDNA kit and Bio-Rad iScript sample preparation reagent). Using these reagents, we are able to adapt the qRT-PCR assay into high-throughput screening of drugs in vitro (i.e., 96-well and 384-well formats for the cultivation of parasites and qRT-PCR detection, respectively). This qRT-PCR protocol is able to give a >150-fold linear dynamic range using samples isolated from cells infected with various numbers of parasites. The new assay is also validated by the NIH-recommended intra-plate, inter-plate, and inter-day uniformity tests. The robustness and effectiveness of the assay are also confirmed by evaluating the anti-cryptosporidial efficacy of paromomycin and by a small scale screening of compounds. PMID:26441920

  13. Quantitative RT-PCR assay for high-throughput screening (HTS) of drugs against the growth of Cryptosporidium parvum in vitro.

    PubMed

    Zhang, Haili; Zhu, Guan

    2015-01-01

    Our laboratory has previously developed a qRT-PCR assay to assess drug efficacy on the growth of Cryptosporidium parvum in vitro by detecting the levels of parasite 18S rRNA. This approach displayed up to four orders of magnitude of linear dynamic range and was much less labor-intensive than the traditional microscopic methods. However, conventional qRT-PCR protocol is not very amendable to high-throughput analysis when total RNA needs to be purified by lengthy, multi-step procedures. Recently, several commercial reagents are available for preparing cell lysates that could be directly used in downstream qRT-PCR analysis (e.g., Ambion Cell-to-cDNA kit and Bio-Rad iScript sample preparation reagent). Using these reagents, we are able to adapt the qRT-PCR assay into high-throughput screening of drugs in vitro (i.e., 96-well and 384-well formats for the cultivation of parasites and qRT-PCR detection, respectively). This qRT-PCR protocol is able to give a >150-fold linear dynamic range using samples isolated from cells infected with various numbers of parasites. The new assay is also validated by the NIH-recommended intra-plate, inter-plate, and inter-day uniformity tests. The robustness and effectiveness of the assay are also confirmed by evaluating the anti-cryptosporidial efficacy of paromomycin and by a small scale screening of compounds.

  14. Microwave-Accelerated Metal-Enhanced Fluorescence (MAMEF) with silver colloids in 96-well plates: Application to ultra fast and sensitive immunoassays, High Throughput Screening and drug discovery.

    PubMed

    Aslan, Kadir; Holley, Patrick; Geddes, Chris D

    2006-05-30

    Fluorescence detection is the basis of most assays used in drug discovery and High Throughput Screening (HTS) today. In all of these assays, assay rapidity and sensitivity is a primary concern, the sensitivity determined by both the quantum yield of the fluorophores and efficiency of the detection system, while rapidity is determined by the physical and biophysical parameters of temperature, concentration, assay bioaffinity, etc. In this paper we describe a platform technology that promises to fundamentally address these two physical constraints of sensitivity and rapidity. By combining the use of Metal-Enhanced Fluorescence (MEF), a near-field effect that can significantly enhance fluorescence signatures, with low power microwave heating, we can significantly increase the sensitivity of surface assays as well as >95% kinetically complete the assay within a few seconds. In addition, the metallic nanostructures used to facilitate MEF appear to be preferentially heated as compared to the surface assay fluid, advantageously localizing the MEF and heating around the nanostructures. To demonstrate proof of principle, a 96-well plate has been functionalized with silver nanostructures, and a model protein avidin-biotin assay studied. In our findings, a greater than 5-fold fluorescence enhancement coupled with a approximately 90-fold increase in assay kinetics was observed, but with no assay washing steps needed due to the silver-enhanced evanescent field mode of excitation. These findings promise to strongly facilitate high throughput fluorescence-based processes, such as in biology, drug discovery and general compound screening.

  15. Monitoring antimalarial drug resistance: Applying lessons learned from the past in a fast-moving present.

    PubMed

    Sibley, Carol Hopkins; Price, Ric N

    2012-12-01

    The need for robust surveillance of antimalarial drugs is more urgent than it has ever been. In the western region of Cambodia, artemisinin resistance has emerged in Plasmodium falciparum and threatens to undermine the efficacy of highly effective artemisinin combination therapies. Although some manfestations of artemisinin tolerance are unique to this class of drug, many of its properties mirror previous experience in understanding and tracking resistance to other antimalarials. In this review we outline the spectrum of approaches that were developed to understand the evolution and spread of antifolate resistance, highlighting the importance of integrating information from different methodologies towards a better understanding of the underlying biologic processes. We consider how to apply our experience in investigating and attempting to contain antifolate resistance to inform our prospective assessment of novel antimalarial resistance patterns and their subsequent spread.

  16. Rational Design of Proteasome Inhibitors as Antimalarial Drugs.

    PubMed

    Le Chapelain, Camille; Groll, Michael

    2016-05-23

    One life, two strategies: Crucial structural differences between the human and the Plasmodium falciparum proteasomes were recently identified. A combination of cryo-EM and functional characterization enabled the design of a selective antimalarial proteasome inhibitor that shows low toxicity in the host. When used with artemisinin, this ligand offers a new approach for the efficient treatment of malaria at all stages of the parasite lifecycle.

  17. A High-Throughput Fluorescence-Based Assay System for Appetite-Regulating Gene and Drug Screening

    PubMed Central

    Shimada, Yasuhito; Hirano, Minoru; Nishimura, Yuhei; Tanaka, Toshio

    2012-01-01

    The increasing number of people suffering from metabolic syndrome and obesity is becoming a serious problem not only in developed countries, but also in developing countries. However, there are few agents currently approved for the treatment of obesity. Those that are available are mainly appetite suppressants and gastrointestinal fat blockers. We have developed a simple and rapid method for the measurement of the feeding volume of Danio rerio (zebrafish). This assay can be used to screen appetite suppressants and enhancers. In this study, zebrafish were fed viable paramecia that were fluorescently-labeled, and feeding volume was measured using a 96-well microplate reader. Gene expression analysis of brain-derived neurotrophic factor (bdnf), knockdown of appetite-regulating genes (neuropeptide Y, preproinsulin, melanocortin 4 receptor, agouti related protein, and cannabinoid receptor 1), and the administration of clinical appetite suppressants (fluoxetine, sibutramine, mazindol, phentermine, and rimonabant) revealed the similarity among mechanisms regulating appetite in zebrafish and mammals. In combination with behavioral analysis, we were able to evaluate adverse effects on locomotor activities from gene knockdown and chemical treatments. In conclusion, we have developed an assay that uses zebrafish, which can be applied to high-throughput screening and target gene discovery for appetite suppressants and enhancers. PMID:23300705

  18. A high-throughput fluorescence-based assay system for appetite-regulating gene and drug screening.

    PubMed

    Shimada, Yasuhito; Hirano, Minoru; Nishimura, Yuhei; Tanaka, Toshio

    2012-01-01

    The increasing number of people suffering from metabolic syndrome and obesity is becoming a serious problem not only in developed countries, but also in developing countries. However, there are few agents currently approved for the treatment of obesity. Those that are available are mainly appetite suppressants and gastrointestinal fat blockers. We have developed a simple and rapid method for the measurement of the feeding volume of Danio rerio (zebrafish). This assay can be used to screen appetite suppressants and enhancers. In this study, zebrafish were fed viable paramecia that were fluorescently-labeled, and feeding volume was measured using a 96-well microplate reader. Gene expression analysis of brain-derived neurotrophic factor (bdnf), knockdown of appetite-regulating genes (neuropeptide Y, preproinsulin, melanocortin 4 receptor, agouti related protein, and cannabinoid receptor 1), and the administration of clinical appetite suppressants (fluoxetine, sibutramine, mazindol, phentermine, and rimonabant) revealed the similarity among mechanisms regulating appetite in zebrafish and mammals. In combination with behavioral analysis, we were able to evaluate adverse effects on locomotor activities from gene knockdown and chemical treatments. In conclusion, we have developed an assay that uses zebrafish, which can be applied to high-throughput screening and target gene discovery for appetite suppressants and enhancers. PMID:23300705

  19. The University of Kansas High-Throughput Screening laboratory. Part I: meeting drug-discovery needs in the heartland of America with entrepreneurial flair.

    PubMed

    McDonald, Peter R; Roy, Anuradha; Chaguturu, Rathnam

    2011-05-01

    The University of Kansas High-Throughput Screening (KU HTS) core is a state-of-the-art drug-discovery facility with an entrepreneurial open-service policy, which provides centralized resources supporting public- and private-sector research initiatives. The KU HTS core applies pharmaceutical industry project-management principles in an academic setting by bringing together multidisciplinary teams to fill critical scientific and technology gaps, using an experienced team of industry-trained researchers and project managers. The KU HTS proactively engages in supporting grant applications for extramural funding, intellectual-property management and technology transfer. The KU HTS staff further provides educational opportunities for the KU faculty and students to learn cutting-edge technologies in drug-discovery platforms through seminars, workshops, internships and course teaching. This is the first instalment of a two-part contribution from the KU HTS laboratory. PMID:21644824

  20. A new high-throughput method utilizing porous silica-based nano-composites for the determination of partition coefficients of drug candidates.

    PubMed

    Yu, Chih H; Tam, Kin; Tsang, Shik C

    2011-09-01

    We show that highly porous silica-based nanoparticles prepared via micro-emulsion and sol-gel techniques are stable colloids in aqueous solution. By incorporating a magnetic core into the porous silica nano-composite, it is found that the material can be rapidly separated (precipitated) upon exposure to an external magnetic field. Alternatively, the porous silica nanoparticles without magnetic cores can be equally separated from solution by applying a high-speed centrifugation. Using these silica-based nanostructures a new high-throughput method for the determination of partition coefficient for water/n-octanol is hereby described. First, a tiny quantity of n-octanol phase is pre-absorbed in the porous silica nano-composite colloids, which allows an establishment of interface at nano-scale between the adsorbed n-octanol with the bulk aqueous phase. Organic compounds added to the mixture can therefore undergo a rapid partition between the two phases. The concentration of drug compound in the supernatant in a small vial can be determined by UV-visible absorption spectroscopy. With the adaptation of a robotic liquid handler, a high-throughput technology for the determination of partition coefficients of drug candidates can be employed for drug screening in the industry based on these nano-separation skills. The experimental results clearly suggest that this new method can provide partition coefficient values of potential drug candidates comparable to the conventional shake-flask method but requires much shorter analytical time and lesser quantity of chemicals. PMID:21780284

  1. Formation of the diuretic chlorazanil from the antimalarial drug proguanil--implications for sports drug testing.

    PubMed

    Thevis, Mario; Geyer, Hans; Thomas, Andreas; Tretzel, Laura; Bailloux, Isabelle; Buisson, Corinne; Lasne, Francoise; Schaefer, Maximilian S; Kienbaum, Peter; Mueller-Stoever, Irmela; Schänzer, Wilhelm

    2015-11-10

    Chlorazanil (Ordipan, N-(4-chlorophenyl)-1,3,5-triazine-2,4-diamine) is a diuretic agent and as such prohibited in sport according to the regulations of the World Anti-Doping Agency (WADA). Despite its introduction into clinical practice in the late 1950s, the worldwide very first two adverse analytical findings were registered only in 2014, being motive for an in-depth investigation of these cases. Both individuals denied the intake of the drug; however, the athletes did declare the use of the antimalarial prophylactic agent proguanil due to temporary residences in African countries. A structural similarity between chlorazanil and proguanil is given but no direct metabolic relation has been reported in the scientific literature. Moreover, chlorazanil has not been confirmed as a drug impurity of proguanil. Proguanil however is metabolized in humans to N-(4-chlorophenyl)-biguanide, which represents a chemical precursor in the synthesis of chlorazanil. In the presence of formic acid, formaldehyde, or formic acid esters, N-(4-chlorophenyl)-biguanide converts to chlorazanil. In order to probe for potential sources of the chlorazanil detected in the doping control samples, drug formulations containing proguanil and urine samples of individuals using proguanil as antimalarial drug were subjected to liquid chromatography-high resolution/high accuracy mass spectrometry. In addition, in vitro simulations with 4-chlorophenyl-biguanide and respective reactants were conducted in urine and resulting specimens analyzed for the presence of chlorazanil. While no chlorazanil was found in drug formulations, the urine samples of 2 out of 4 proguanil users returned findings for chlorazanil at low ng/mL levels, similar to the adverse analytical findings in the doping control samples. Further, in the presence of formaldehyde, formic acid and related esters, 4-chlorophenyl-biguanide was found to produce chlorazanil in human urine, suggesting that the detection of the obsolete diuretic

  2. Potentiation of antimalarial drug action by chlorpheniramine against multidrug-resistant Plasmodium falciparum in vitro.

    PubMed

    Nakornchai, Sunan; Konthiang, Phattanapong

    2006-09-01

    Chlorpheniramine, a histamine H1 receptor antagonist, was assayed for in vitro antimalarial activity against multidrug-resistant Plasmodium falciparum K1 strain and chloroquine-resistant P. falciparum T9/94 clone, by measuring the 3H-hypoxanthine incorporation. Chlorphenirame inhibited P. falciparum K1 and T9/94 growth with IC50 values of 136.0+/-40.2 microM and 102.0+/-22.6 microM respectively. A combination of antimalarial drug and chlorpheniramine was tested against resistant P. falciparum in vitro. Isobologram analysis showed that chlorpheniramine exerts marked synergistic action on chloroquine against P. falciparum K1 and T9/94. Chlorpheniramine also potentiated antimalarial action of mefloquine, quinine or pyronaridine against both of the resistant strains of P. falciparum. However, chlorpheniramine antagonism with artesunate was obtained in both P. falciparum K1 and T9/94. The results in this study indicate that antihistaminic drugs may be promising candidates for potentiating antimalarial drug action against drug resistant malarial parasites.

  3. Serine Proteases of Malaria Parasite Plasmodium falciparum: Potential as Antimalarial Drug Targets

    PubMed Central

    2014-01-01

    Malaria is a major global parasitic disease and a cause of enormous mortality and morbidity. Widespread drug resistance against currently available antimalarials warrants the identification of novel drug targets and development of new drugs. Malarial proteases are a group of molecules that serve as potential drug targets because of their essentiality for parasite life cycle stages and feasibility of designing specific inhibitors against them. Proteases belonging to various mechanistic classes are found in P. falciparum, of which serine proteases are of particular interest due to their involvement in parasite-specific processes of egress and invasion. In P. falciparum, a number of serine proteases belonging to chymotrypsin, subtilisin, and rhomboid clans are found. This review focuses on the potential of P. falciparum serine proteases as antimalarial drug targets. PMID:24799897

  4. Amphiphilic dendritic derivatives as nanocarriers for the targeted delivery of antimalarial drugs.

    PubMed

    Movellan, Julie; Urbán, Patricia; Moles, Ernest; de la Fuente, Jesús M; Sierra, Teresa; Serrano, José Luis; Fernàndez-Busquets, Xavier

    2014-09-01

    It can be foreseen that in a future scenario of malaria eradication, a varied armamentarium will be required, including strategies for the targeted administration of antimalarial compounds. The development of nanovectors capable of encapsulating drugs and of delivering them to Plasmodium-infected cells with high specificity and efficacy and at an affordable cost is of particular interest. With this objective, dendritic derivatives based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Pluronic(®) polymers have been herein explored. Four different dendritic derivatives have been tested for their capacity to encapsulate the antimalarial drugs chloroquine (CQ) and primaquine (PQ), their specific targeting to Plasmodium-infected red blood cells (pRBCs), and their antimalarial activity in vitro against the human pathogen Plasmodium falciparum and in vivo against the rodent malaria species Plasmodium yoelii. The results obtained have allowed the identification of two dendritic derivatives exhibiting specific targeting to pRBCs vs. non-infected RBCs, which reduce the in vitro IC50 of CQ and PQ by ca. 3- and 4-fold down to 4.0 nm and 1.1 μm, respectively. This work on the application of dendritic derivatives to antimalarial targeted drug delivery opens the way for the use of this new type of chemicals in future malaria eradication programs.

  5. The University of Kansas High-Throughput Screening Laboratory. Part II: enabling collaborative drug-discovery partnerships through cutting-edge screening technology

    PubMed Central

    McDonald, Peter R; Roy, Anuradha; Chaguturu, Rathnam

    2011-01-01

    The University of Kansas High-Throughput Screening (KU HTS) core is a state-of-the-art drug-discovery facility with an entrepreneurial open-service policy, which provides centralized resources supporting public- and private-sector research initiatives. The KU HTS core was established in 2002 at the University of Kansas with support from an NIH grant and the state of Kansas. It collaborates with investigators from national and international academic, nonprofit and pharmaceutical organizations in executing HTS-ready assay development and screening of chemical libraries for target validation, probe selection, hit identification and lead optimization. This is part two of a contribution from the KU HTS laboratory. PMID:21806374

  6. A High-Throughput Screening Assay for the Identification of Flavivirus NS5 Capping Enzyme GTP-Binding Inhibitors: Implications for Antiviral Drug Development

    PubMed Central

    GEISS, BRIAN J.; STAHLA-BEEK, HILLARY J.; HANNAH, AMANDA M.; GARI, HAMID H.; HENDERSON, BRITTNEY R.; SAEEDI, BEJAN J.; KEENAN, SUSAN M.

    2012-01-01

    There are no effective antivirals currently available for the treatment of flavivirus infection in humans. As such, the identification and characterization of novel drug target sites are critical to developing new classes of antiviral drugs. The flavivirus NS5 N-terminal capping enzyme (CE) is vital for the formation of the viral RNA cap structure, which directs viral polyprotein translation and stabilizes the 5′ end of the viral genome. The structure of the flavivirus CE has been solved, and a detailed understanding of the CE–guanosine triphosphate (GTP) and CE–RNA cap interactions is available. Because of the essential nature of the interaction for viral replication, disrupting CE–GTP binding is an attractive approach for drug development. The authors have previously developed a robust assay for monitoring CE–GTP binding in real time. They adapted this assay for high-throughput screening and performed a pilot screen of 46 323 commercially available compounds. A number of small-molecule inhibitors capable of displacing a fluorescently labeled GTP in vitro were identified, and a second functional assay was developed to identify false positives. The results presented indicate that the flavivirus CE cap-binding site is a valuable new target site for antiviral drug discovery and should be further exploited for broad-spectrum anti-flaviviral drug development. PMID:21788392

  7. Characterization of the Plasmodium falciparum M17 leucyl aminopeptidase. A protease involved in amino acid regulation with potential for antimalarial drug development.

    PubMed

    Stack, Colin M; Lowther, Jonathan; Cunningham, Eithne; Donnelly, Sheila; Gardiner, Donald L; Trenholme, Katharine R; Skinner-Adams, Tina S; Teuscher, Franka; Grembecka, Jolanta; Mucha, Artur; Kafarski, Pawel; Lua, Linda; Bell, Angus; Dalton, John P

    2007-01-19

    Amino acids generated from the catabolism of hemoglobin by intra-erythrocytic malaria parasites are not only essential for protein synthesis but also function in maintaining an osmotically stable environment, and creating a gradient by which amino acids that are rare or not present in hemoglobin are drawn into the parasite from host serum. We have proposed that a Plasmodium falciparum M17 leucyl aminopeptidase (PfLAP) generates and regulates the internal pool of free amino acids and therefore represents a target for novel antimalarial drugs. This enzyme has been expressed in insect cells as a functional 320-kDa homo-hexamer that is optimally active at neutral or alkaline pH, is dependent on metal ions for activity, and exhibits a substrate preference for N-terminally exposed hydrophobic amino acids, particularly leucine. PfLAP is produced by all stages in the intra-erythrocytic developmental cycle of malaria but was most highly expressed by trophozoites, a stage at which hemoglobin degradation and parasite protein synthesis are elevated. The enzyme was located by immunohistochemical methods and by transfecting malaria cells with a PfLAP-green fluorescent protein construct, to the cytosolic compartment of the cell at all developmental stages, including segregated merozoites. Amino acid dipeptide analogs, such as bestatin and its derivatives, are potent inhibitors of the protease and also block the growth of P. falciparum malaria parasites in culture. This study provides a biochemical basis for the antimalarial activity of aminopeptidase inhibitors. Availability of functionally active recombinant PfLAP, coupled with a simple enzymatic readout, will aid medicinal chemistry and/or high throughput approaches for the future design/discovery of new antimalarial drugs. PMID:17107951

  8. Discovery of New Compounds Active against Plasmodium falciparum by High Throughput Screening of Microbial Natural Products

    PubMed Central

    Pérez-Moreno, Guiomar; Cantizani, Juan; Sánchez-Carrasco, Paula; Ruiz-Pérez, Luis Miguel; Martín, Jesús; el Aouad, Noureddine; Pérez-Victoria, Ignacio; Tormo, José Rubén; González-Menendez, Víctor; González, Ignacio; de Pedro, Nuria; Reyes, Fernando; Genilloud, Olga; Vicente, Francisca; González-Pacanowska, Dolores

    2016-01-01

    Due to the low structural diversity within the set of antimalarial drugs currently available in the clinic and the increasing number of cases of resistance, there is an urgent need to find new compounds with novel modes of action to treat the disease. Microbial natural products are characterized by their large diversity provided in terms of the chemical complexity of the compounds and the novelty of structures. Microbial natural products extracts have been underexplored in the search for new antiparasitic drugs and even more so in the discovery of new antimalarials. Our objective was to find new druggable natural products with antimalarial properties from the MEDINA natural products collection, one of the largest natural product libraries harboring more than 130,000 microbial extracts. In this work, we describe the optimization process and the results of a phenotypic high throughput screen (HTS) based on measurements of Plasmodium lactate dehydrogenase. A subset of more than 20,000 extracts from the MEDINA microbial products collection has been explored, leading to the discovery of 3 new compounds with antimalarial activity. In addition, we report on the novel antiplasmodial activity of 4 previously described natural products. PMID:26735308

  9. Cos-Seq for high-throughput identification of drug target and resistance mechanisms in the protozoan parasite Leishmania.

    PubMed

    Gazanion, Élodie; Fernández-Prada, Christopher; Papadopoulou, Barbara; Leprohon, Philippe; Ouellette, Marc

    2016-05-24

    Innovative strategies are needed to accelerate the identification of antimicrobial drug targets and resistance mechanisms. Here we develop a sensitive method, which we term Cosmid Sequencing (or "Cos-Seq"), based on functional cloning coupled to next-generation sequencing. Cos-Seq identified >60 loci in the Leishmania genome that were enriched via drug selection with methotrexate and five major antileishmanials (antimony, miltefosine, paromomycin, amphotericin B, and pentamidine). Functional validation highlighted both known and previously unidentified drug targets and resistance genes, including novel roles for phosphatases in resistance to methotrexate and antimony, for ergosterol and phospholipid metabolism genes in resistance to miltefosine, and for hypothetical proteins in resistance to paromomycin, amphothericin B, and pentamidine. Several genes/loci were also found to confer resistance to two or more antileishmanials. This screening method will expedite the discovery of drug targets and resistance mechanisms and is easily adaptable to other microorganisms. PMID:27162331

  10. Microfluidic Cell Culture and Its Application in High Throughput Drug Screening: Cardiotoxicity Assay for hERG Channels

    PubMed Central

    Su, Xiaojing; Young, Edmond W.K.; Underkofler, Heather A. S.; Kamp, Timothy J.; January, Craig T.; Beebe, David J.

    2011-01-01

    Evaluation of drug cardiotoxicity is essential to the safe development of novel pharmaceuticals. Assessing a compound's risk for prolongation of the surface electrocardiographic QT interval, and hence risk for life threatening arrhythmias is mandated before approval of nearly all new pharmaceuticals. QT prolongation has most commonly been associated with loss of current through hERG (human ether-a-go-go related gene) potassium ion channels due to direct block of the ion channel by drugs or occasionally by inhibition of the plasma membrane expression of the channel protein. To develop an efficient, reliable, and cost-effective hERG screening assay for detecting drug-mediated disruption of hERG membrane trafficking, we demonstrate the use of microfluidic-based systems to improve throughput and lower cost of current methods. We validate our microfluidics array platform in polystyrene (PS), cyclo-olefin polymer (COP) and poly(dimethylsiloxane) (PDMS) microchannels for drug-induced disruption of hERG trafficking by culturing stably transfected HEK cells that overexpressed hERG (WT-hERG), and studying their morphology, proliferation rates, hERG protein expression, and response to drug treatment. Our results show that WT-hERG cells readily proliferate in PS, COP, and PDMS microfluidic channels. We demonstrated that conventional Western blot analysis was possible using cell lysate extracted from a single microchannel. The Western blot analysis also provided important evidence that WT-hERG cells cultured in microchannels maintained regular (well plate-based) expression of hERG. We further showed that experimental procedures can be streamlined by using direct in-channel immunofluorescent staining in conjunction with detection using an infrared scanner. Finally, treatment of WT-hERG cells with five different drugs suggested that PS (and COP) microchannels were more suitable than PDMS microchannels for drug screening applications, particularly for tests involving hydrophobic

  11. Irrational use of antimalarial drugs in rural areas of eastern Pakistan: a random field study

    PubMed Central

    2012-01-01

    Background Prescription of antimalarial drugs in the absence of malarial disease is a common practice in countries where malaria is endemic. However, unwarranted use of such drugs can cause side effects in some people and is a financial drain on local economies. In this study, we surveyed the prevalence of malaria parasites in humans, and the prevalence of the malaria transmitting mosquito vectors in the study area. We also investigated the use of antimalarial drugs in the local people. We focused on randomly selected rural areas of eastern Pakistan where no malaria cases had been reported since May 2004. Methods Mass blood surveys, active case detection, passive case detection, and vector density surveys were carried out in selected areas of Sargodha district from September 2008 to August 2009. Data pertaining to the quantities and types of antimalarial drugs used in these areas were collected from health centers, pharmacies, and the district CDC program of the Health Department of the Government of the Punjab. Results Seven hundred and forty four blood samples were examined, resulting in a Blood Examination Rate (BER) of 3.18; microscopic analysis of blood smears showed that none of the samples were positive for malaria parasites. Investigation of the mosquito vector density in 43 living rooms (bedrooms or rooms used for sleeping), 23 stores, and 32 animal sheds, revealed no vectors capable of transmitting malaria in these locations. In contrast, the density of Culex mosquitoes was high. Substantial consumption of a variety of antimalarial tablets, syrups, capsules and injections costing around 1000 US$, was documented for the region. Conclusion Use of antimalarial drugs in the absence of malarial infection or the vectors that transmit the disease was common in the study area. Continuous use of such drugs, not only in Pakistan, but in other parts of the world, may lead to drug-induced side effects amongst users. Better training of health care professionals is

  12. Metabolic Dysregulation Induced in Plasmodium falciparum by Dihydroartemisinin and Other Front-Line Antimalarial Drugs.

    PubMed

    Cobbold, Simon A; Chua, Hwa H; Nijagal, Brunda; Creek, Darren J; Ralph, Stuart A; McConville, Malcolm J

    2016-01-15

    Detailed information on the mode of action of antimalarial drugs can be used to improve existing drugs, identify new drug targets, and understand the basis of drug resistance. In this study we describe the use of a time-resolved, mass spectrometry (MS)-based metabolite profiling approach to map the metabolic perturbations induced by a panel of clinical antimalarial drugs and inhibitors on Plasmodium falciparum asexual blood stages. Drug-induced changes in metabolite levels in P. falciparum-infected erythrocytes were monitored over time using gas chromatography-MS and liquid chromatography-MS and changes in specific metabolic fluxes confirmed by nonstationary [(13)C]-glucose labeling. Dihydroartemisinin (DHA) was found to disrupt hemoglobin catabolism within 1 hour of exposure, resulting in a transient decrease in hemoglobin-derived peptides. Unexpectedly, it also disrupted pyrimidine biosynthesis, resulting in increased [(13)C]-glucose flux toward malate production, potentially explaining the susceptibility of P. falciparum to DHA during early blood-stage development. Unique metabolic signatures were also found for atovaquone, chloroquine, proguanil, cycloguanil and methylene blue. We also show that this approach can be used to identify the mode of action of novel antimalarials, such as the compound Torin 2, which inhibits hemoglobin catabolism. PMID:26150544

  13. Lead Clinical and Preclinical Antimalarial Drugs Can Significantly Reduce Sporozoite Transmission to Vertebrate Populations

    PubMed Central

    Upton, L. M.; Brock, P. M.; Churcher, T. S.; Ghani, A. C.; Gething, P. W.; Delves, M. J.; Sala, K. A.; Leroy, D.; Sinden, R. E.

    2014-01-01

    To achieve malarial elimination, we must employ interventions that reduce the exposure of human populations to infectious mosquitoes. To this end, numerous antimalarial drugs are under assessment in a variety of transmission-blocking assays which fail to measure the single crucial criteria of a successful intervention, namely impact on case incidence within a vertebrate population (reduction in reproductive number/effect size). Consequently, any reduction in new infections due to drug treatment (and how this may be influenced by differing transmission settings) is not currently examined, limiting the translation of any findings. We describe the use of a laboratory population model to assess how individual antimalarial drugs can impact the number of secondary Plasmodium berghei infections over a cycle of transmission. We examine the impact of multiple clinical and preclinical drugs on both insect and vertebrate populations at multiple transmission settings. Both primaquine (>6 mg/kg of body weight) and NITD609 (8.1 mg/kg) have significant impacts across multiple transmission settings, but artemether and lumefantrine (57 and 11.8 mg/kg), OZ439 (6.5 mg/kg), and primaquine (<1.25 mg/kg) demonstrated potent efficacy only at lower-transmission settings. While directly demonstrating the impact of antimalarial drug treatment on vertebrate populations, we additionally calculate effect size for each treatment, allowing for head-to-head comparison of the potential impact of individual drugs within epidemiologically relevant settings, supporting their usage within elimination campaigns. PMID:25385107

  14. Mechanisms of hematin crystallization and inhibition by the antimalarial drug chloroquine.

    PubMed

    Olafson, Katy N; Ketchum, Megan A; Rimer, Jeffrey D; Vekilov, Peter G

    2015-04-21

    Hematin crystallization is the primary mechanism of heme detoxification in malaria parasites and the target of the quinoline class of antimalarials. Despite numerous studies of malaria pathophysiology, fundamental questions regarding hematin growth and inhibition remain. Among them are the identity of the crystallization medium in vivo, aqueous or organic; the mechanism of crystallization, classical or nonclassical; and whether quinoline antimalarials inhibit crystallization by sequestering hematin in the solution, or by blocking surface sites crucial for growth. Here we use time-resolved in situ atomic force microscopy (AFM) and show that the lipid subphase in the parasite may be a preferred growth medium. We provide, to our knowledge, the first evidence of the molecular mechanisms of hematin crystallization and inhibition by chloroquine, a common quinoline antimalarial drug. AFM observations demonstrate that crystallization strictly follows a classical mechanism wherein new crystal layers are generated by 2D nucleation and grow by the attachment of solute molecules. We identify four classes of surface sites available for binding of potential drugs and propose respective mechanisms of drug action. Further studies reveal that chloroquine inhibits hematin crystallization by binding to molecularly flat {100} surfaces. A 2-μM concentration of chloroquine fully arrests layer generation and step advancement, which is ∼10(4)× less than hematin's physiological concentration. Our results suggest that adsorption at specific growth sites may be a general mode of hemozoin growth inhibition for the quinoline antimalarials. Because the atomic structures of the identified sites are known, this insight could advance the future design and/or optimization of new antimalarials. PMID:25831526

  15. Mechanisms of hematin crystallization and inhibition by the antimalarial drug chloroquine.

    PubMed

    Olafson, Katy N; Ketchum, Megan A; Rimer, Jeffrey D; Vekilov, Peter G

    2015-04-21

    Hematin crystallization is the primary mechanism of heme detoxification in malaria parasites and the target of the quinoline class of antimalarials. Despite numerous studies of malaria pathophysiology, fundamental questions regarding hematin growth and inhibition remain. Among them are the identity of the crystallization medium in vivo, aqueous or organic; the mechanism of crystallization, classical or nonclassical; and whether quinoline antimalarials inhibit crystallization by sequestering hematin in the solution, or by blocking surface sites crucial for growth. Here we use time-resolved in situ atomic force microscopy (AFM) and show that the lipid subphase in the parasite may be a preferred growth medium. We provide, to our knowledge, the first evidence of the molecular mechanisms of hematin crystallization and inhibition by chloroquine, a common quinoline antimalarial drug. AFM observations demonstrate that crystallization strictly follows a classical mechanism wherein new crystal layers are generated by 2D nucleation and grow by the attachment of solute molecules. We identify four classes of surface sites available for binding of potential drugs and propose respective mechanisms of drug action. Further studies reveal that chloroquine inhibits hematin crystallization by binding to molecularly flat {100} surfaces. A 2-μM concentration of chloroquine fully arrests layer generation and step advancement, which is ∼10(4)× less than hematin's physiological concentration. Our results suggest that adsorption at specific growth sites may be a general mode of hemozoin growth inhibition for the quinoline antimalarials. Because the atomic structures of the identified sites are known, this insight could advance the future design and/or optimization of new antimalarials.

  16. Impact of prepackaging antimalarial drugs on cost to patients and compliance with treatment.

    PubMed Central

    Yeboah-Antwi, K.; Gyapong, J. O.; Asare, I. K.; Barnish, G.; Evans, D. B.; Adjei, S.

    2001-01-01

    OBJECTIVE: To examine the extent to which district health teams could reduce the burden of malaria, a continuing major cause of mortality and morbidity, in a situation where severe resource constraints existed and integrated care was provided. METHODS: Antimalarial drugs were prepackaged into unit doses in an attempt to improve compliance with full courses of chemotherapy. FINDINGS: Compliance improved by approximately 20% in both adults and children. There were 50% reductions in cost to patients, waiting time at dispensaries and drug wastage at facilities. The intervention, which tended to improve both case and drug management at facilities, was well accepted by health staff and did not involve them in additional working time. CONCLUSION: The prepackaging of antimalarials at the district level offers the prospect of improved compliance and a reduction in the spread of resistance. PMID:11417034

  17. High-Throughput Screening for Identification of Blood-Brain Barrier Integrity Enhancers: A Drug Repurposing Opportunity to Rectify Vascular Amyloid Toxicity.

    PubMed

    Qosa, Hisham; Mohamed, Loqman A; Al Rihani, Sweilem B; Batarseh, Yazan S; Duong, Quoc-Viet; Keller, Jeffrey N; Kaddoumi, Amal

    2016-07-01

    The blood-brain barrier (BBB) is a dynamic interface that maintains brain homeostasis and protects it from free entry of chemicals, toxins, and drugs. The barrier function of the BBB is maintained mainly by capillary endothelial cells that physically separate brain from blood. Several neurological diseases, such as Alzheimer's disease (AD), are known to disrupt BBB integrity. In this study, a high-throughput screening (HTS) was developed to identify drugs that rectify/protect BBB integrity from vascular amyloid toxicity associated with AD progression. Assessing Lucifer Yellow permeation across in-vitro BBB model composed from mouse brain endothelial cells (bEnd3) grown on 96-well plate inserts was used to screen 1280 compounds of Sigma LOPAC®1280 library for modulators of bEnd3 monolayer integrity. HTS identified 62 compounds as disruptors, and 50 compounds as enhancers of the endothelial barrier integrity. From these 50 enhancers, 7 FDA approved drugs were identified with EC50 values ranging from 0.76-4.56 μM. Of these 7 drugs, 5 were able to protect bEnd3-based BBB model integrity against amyloid toxicity. Furthermore, to test the translational potential to humans, the 7 drugs were tested for their ability to rectify the disruptive effect of Aβ in the human endothelial cell line hCMEC/D3. Only 3 (etodolac, granisetron, and beclomethasone) out of the 5 effective drugs in the bEnd3-based BBB model demonstrated a promising effect to protect the hCMEC/D3-based BBB model integrity. These drugs are compelling candidates for repurposing as therapeutic agents that could rectify dysfunctional BBB associated with AD.

  18. High-Throughput Screening for Identification of Blood-Brain Barrier Integrity Enhancers: A Drug Repurposing Opportunity to Rectify Vascular Amyloid Toxicity.

    PubMed

    Qosa, Hisham; Mohamed, Loqman A; Al Rihani, Sweilem B; Batarseh, Yazan S; Duong, Quoc-Viet; Keller, Jeffrey N; Kaddoumi, Amal

    2016-07-01

    The blood-brain barrier (BBB) is a dynamic interface that maintains brain homeostasis and protects it from free entry of chemicals, toxins, and drugs. The barrier function of the BBB is maintained mainly by capillary endothelial cells that physically separate brain from blood. Several neurological diseases, such as Alzheimer's disease (AD), are known to disrupt BBB integrity. In this study, a high-throughput screening (HTS) was developed to identify drugs that rectify/protect BBB integrity from vascular amyloid toxicity associated with AD progression. Assessing Lucifer Yellow permeation across in-vitro BBB model composed from mouse brain endothelial cells (bEnd3) grown on 96-well plate inserts was used to screen 1280 compounds of Sigma LOPAC®1280 library for modulators of bEnd3 monolayer integrity. HTS identified 62 compounds as disruptors, and 50 compounds as enhancers of the endothelial barrier integrity. From these 50 enhancers, 7 FDA approved drugs were identified with EC50 values ranging from 0.76-4.56 μM. Of these 7 drugs, 5 were able to protect bEnd3-based BBB model integrity against amyloid toxicity. Furthermore, to test the translational potential to humans, the 7 drugs were tested for their ability to rectify the disruptive effect of Aβ in the human endothelial cell line hCMEC/D3. Only 3 (etodolac, granisetron, and beclomethasone) out of the 5 effective drugs in the bEnd3-based BBB model demonstrated a promising effect to protect the hCMEC/D3-based BBB model integrity. These drugs are compelling candidates for repurposing as therapeutic agents that could rectify dysfunctional BBB associated with AD. PMID:27392852

  19. A better resolution for integrating methods for monitoring Plasmodium falciparum resistance to antimalarial drugs.

    PubMed

    Abdul-Ghani, Rashad; Al-Maktari, Mohamed T; Al-Shibani, Latifa A; Allam, Amal F

    2014-09-01

    Effective chemotherapy is the mainstay of malaria control. However, resistance of falciparum malaria to antimalarial drugs compromised the efforts to eliminate the disease and led to the resurgence of malaria epidemics. Three main approaches are used to monitor antimalarial drug efficacy and drug resistance; namely, in vivo trials, in vitro/ex vivo assays and molecular markers of drug resistance. Each approach has its implications of use as well as its advantages and drawbacks. Therefore, there is a need to use an integrated approach that would give the utmost effect to detect resistance as early as its emergence and to track it once spread. Such integration becomes increasingly needed in the era of artemisinin-based combination therapy as a forward action to deter resistance. The existence of regional and global networks for the standardization of methodology, provision of high quality reagents for the assessment of antimalarial drug resistance and dissemination of open-access data would help in approaching an integrated resistance surveillance system on a global scale.

  20. Interspecies Allometric Scaling of Antimalarial Drugs and Potential Application to Pediatric Dosing

    PubMed Central

    Senarathna, S. M. D. K. Ganga

    2014-01-01

    Pharmacopeial recommendations for administration of antimalarial drugs are the same weight-based (mg/kg of body weight) doses for children and adults. However, linear calculations are known to underestimate pediatric doses; therefore, interspecies allometric scaling data may have a role in predicting doses in children. We investigated the allometric scaling relationships of antimalarial drugs using data from pharmacokinetic studies in mammalian species. Simple allometry (Y = a × Wb) was utilized and compared to maximum life span potential (MLP) correction. All drugs showed a strong correlation with clearance (CL) in healthy controls. Insufficient data from malaria-infected species other than humans were available for allometric scaling. The allometric exponents (b) for CL of artesunate, dihydroartemisinin (from intravenous artesunate), artemether, artemisinin, clindamycin, piperaquine, mefloquine, and quinine were 0.71, 0.85, 0.66, 0.83, 0.62, 0.96, 0.52, and 0.40, respectively. Clearance was significantly lower in malaria infection than in healthy (adult) humans for quinine (0.07 versus 0.17 liter/h/kg; P = 0.0002) and dihydroartemisinin (0.81 versus 1.11 liters/h/kg; P = 0.04; power = 0.6). Interpolation of simple allometry provided better estimates of CL for children than MLP correction, which generally underestimated CL values. Pediatric dose calculations based on simple allometric exponents were 10 to 70% higher than pharmacopeial (mg/kg) recommendations. Interpolation of interspecies allometric scaling could provide better estimates than linear scaling of adult to pediatric doses of antimalarial drugs; however, the use of a fixed exponent for CL was not supported in the present study. The variability in allometric exponents for antimalarial drugs also has implications for scaling of fixed-dose combinations. PMID:25092696

  1. A High-Throughput In Vitro Drug Screen in a Genetically Engineered Mouse Model of Diffuse Intrinsic Pontine Glioma Identifies BMS-754807 as a Promising Therapeutic Agent

    PubMed Central

    Halvorson, Kyle G.; Barton, Kelly L.; Schroeder, Kristin; Misuraca, Katherine L.; Hoeman, Christine; Chung, Alex; Crabtree, Donna M.; Cordero, Francisco J.; Singh, Raj; Spasojevic, Ivan; Berlow, Noah; Pal, Ranadip; Becher, Oren J.

    2015-01-01

    Diffuse intrinsic pontine gliomas (DIPGs) represent a particularly lethal type of pediatric brain cancer with no effective therapeutic options. Our laboratory has previously reported the development of genetically engineered DIPG mouse models using the RCAS/tv-a system, including a model driven by PDGF-B, H3.3K27M, and p53 loss. These models can serve as a platform in which to test novel therapeutics prior to the initiation of human clinical trials. In this study, an in vitro high-throughput drug screen as part of the DIPG preclinical consortium using cell-lines derived from our DIPG models identified BMS-754807 as a drug of interest in DIPG. BMS-754807 is a potent and reversible small molecule multi-kinase inhibitor with many targets including IGF-1R, IR, MET, TRKA, TRKB, AURKA, AURKB. In vitro evaluation showed significant cytotoxic effects with an IC50 of 0.13 μM, significant inhibition of proliferation at a concentration of 1.5 μM, as well as inhibition of AKT activation. Interestingly, IGF-1R signaling was absent in serum-free cultures from the PDGF-B; H3.3K27M; p53 deficient model suggesting that the antitumor activity of BMS-754807 in this model is independent of IGF-1R. In vivo, systemic administration of BMS-754807 to DIPG-bearing mice did not prolong survival. Pharmacokinetic analysis demonstrated that tumor tissue drug concentrations of BMS-754807 were well below the identified IC50, suggesting that inadequate drug delivery may limit in vivo efficacy. In summary, an unbiased in vitro drug screen identified BMS-754807 as a potential therapeutic agent in DIPG, but BMS-754807 treatment in vivo by systemic delivery did not significantly prolong survival of DIPG-bearing mice. PMID:25748921

  2. Zebrafish swimming behavior as a biomarker for ototoxicity-induced hair cell damage: a high-throughput drug development platform targeting hearing loss.

    PubMed

    Niihori, Maki; Platto, Terry; Igarashi, Suzu; Hurbon, Audriana; Dunn, Allison M; Tran, Phi; Tran, Hung; Mudery, Jordan A; Slepian, Marvin J; Jacob, Abraham

    2015-11-01

    Hearing loss is one of the most common human sensory disabilities, adversely affecting communication, socialization, mood, physical functioning, and quality of life. In addition to age and noise-induced damage, ototoxicity is a common cause of sensorineural hearing loss with chemotherapeutic agents, for example, cisplatin, being a major contributor. Zebrafish (Danio rerio) are an excellent model to study hearing loss as they have neurosensory hair cells on their body surface that are structurally similar to those within the human inner ear. Anatomic assays of toxin-mediated hair cell damage in zebrafish have been established; however, using fish swimming behavior--rheotaxis--as a biomarker for this anatomic damage was only recently described. We hypothesized that, in parallel, multilane measurements of rheotaxis could be used to create a high-throughput platform for drug development assessing both ototoxic and potentially otoprotective compounds in real time. Such a device was created, and results demonstrated a clear dose response between cisplatin exposure, progressive hair cell damage, and reduced rheotaxis in zebrafish. Furthermore, pre-exposure to the otoprotective medication dexamethasone, before cisplatin exposure, partially rescued rheotaxis swimming behavior and hair cell integrity. These results provide the first evidence that rescued swimming behavior can serve as a biomarker for rescued hair cell function. Developing a drug against hearing loss represents an unmet clinical need with global implications. Because hearing loss from diverse etiologies may result from common end-effects at the hair cell level, lessons learned from the present study may be broadly used.

  3. Molecular surveillance of antimalarial drug resistance related genes in Plasmodium falciparum isolates from Eritrea.

    PubMed

    Menegon, Michela; Nurahmed, Abduselam M; Talha, Albadawi A; Nour, Bakri Y M; Severini, Carlo

    2016-05-01

    The introduction of artemisinin-based combination therapy has led to extraordinary results in malaria control, however the recent emergence of partial resistance to artemisinin therapy in Southeast Asia jeopardizes these successes. This study aimed at investigating resistance to the antimalarial drugs by evaluating the polymorphisms in the PfK13, Pfcrt and Pfmdr1 genes in Plasmodium falciparum isolates obtained from patients in Eritrea.

  4. Linking Murine and Human Plasmodium falciparum Challenge Models in a Translational Path for Antimalarial Drug Development

    PubMed Central

    McCarthy, James S.; Marquart, Louise; Sekuloski, Silvana; Trenholme, Katharine; Elliott, Suzanne; Griffin, Paul; Rockett, Rebecca; O'Rourke, Peter; Sloots, Theo; Angulo-Barturen, Iñigo; Ferrer, Santiago; Jiménez-Díaz, María Belén; Martínez, María-Santos; Duparc, Stephan; Leroy, Didier; Wells, Timothy N. C.; Baker, Mark

    2016-01-01

    Effective progression of candidate antimalarials is dependent on optimal dosing in clinical studies, which is determined by a sound understanding of pharmacokinetics and pharmacodynamics (PK/PD). Recently, two important translational models for antimalarials have been developed: the NOD/SCID/IL2Rγ−/− (NSG) model, whereby mice are engrafted with noninfected and Plasmodium falciparum-infected human erythrocytes, and the induced blood-stage malaria (IBSM) model in human volunteers. The antimalarial mefloquine was used to directly measure the PK/PD in both models, which were compared to previously published trial data for malaria patients. The clinical part was a single-center, controlled study using a blood-stage Plasmodium falciparum challenge inoculum in volunteers to characterize the effectiveness of mefloquine against early malaria. The study was conducted in three cohorts (n = 8 each) using different doses of mefloquine. The characteristic delay in onset of action of about 24 h was seen in both NSG and IBSM systems. In vivo 50% inhibitory concentrations (IC50s) were estimated at 2.0 μg/ml and 1.8 μg/ml in the NSG and IBSM models, respectively, aligning with 1.8 μg/ml reported previously for patients. In the IBSM model, the parasite reduction ratios were 157 and 195 for the 10- and 15-mg/kg doses, within the range of previously reported clinical data for patients but significantly lower than observed in the mouse model. Linking mouse and human challenge models to clinical trial data can accelerate the accrual of critical data on antimalarial drug activity. Such data can guide large clinical trials required for development of urgently needed novel antimalarial combinations. (This trial was registered at the Australian New Zealand Clinical Trials Registry [http://anzctr.org.au] under registration number ACTRN12612000323820.) PMID:27044554

  5. Linking Murine and Human Plasmodium falciparum Challenge Models in a Translational Path for Antimalarial Drug Development.

    PubMed

    McCarthy, James S; Marquart, Louise; Sekuloski, Silvana; Trenholme, Katharine; Elliott, Suzanne; Griffin, Paul; Rockett, Rebecca; O'Rourke, Peter; Sloots, Theo; Angulo-Barturen, Iñigo; Ferrer, Santiago; Jiménez-Díaz, María Belén; Martínez, María-Santos; Hooft van Huijsduijnen, Rob; Duparc, Stephan; Leroy, Didier; Wells, Timothy N C; Baker, Mark; Möhrle, Jörg J

    2016-06-01

    Effective progression of candidate antimalarials is dependent on optimal dosing in clinical studies, which is determined by a sound understanding of pharmacokinetics and pharmacodynamics (PK/PD). Recently, two important translational models for antimalarials have been developed: the NOD/SCID/IL2Rγ(-/-) (NSG) model, whereby mice are engrafted with noninfected and Plasmodium falciparum-infected human erythrocytes, and the induced blood-stage malaria (IBSM) model in human volunteers. The antimalarial mefloquine was used to directly measure the PK/PD in both models, which were compared to previously published trial data for malaria patients. The clinical part was a single-center, controlled study using a blood-stage Plasmodium falciparum challenge inoculum in volunteers to characterize the effectiveness of mefloquine against early malaria. The study was conducted in three cohorts (n = 8 each) using different doses of mefloquine. The characteristic delay in onset of action of about 24 h was seen in both NSG and IBSM systems. In vivo 50% inhibitory concentrations (IC50s) were estimated at 2.0 μg/ml and 1.8 μg/ml in the NSG and IBSM models, respectively, aligning with 1.8 μg/ml reported previously for patients. In the IBSM model, the parasite reduction ratios were 157 and 195 for the 10- and 15-mg/kg doses, within the range of previously reported clinical data for patients but significantly lower than observed in the mouse model. Linking mouse and human challenge models to clinical trial data can accelerate the accrual of critical data on antimalarial drug activity. Such data can guide large clinical trials required for development of urgently needed novel antimalarial combinations. (This trial was registered at the Australian New Zealand Clinical Trials Registry [http://anzctr.org.au] under registration number ACTRN12612000323820.). PMID:27044554

  6. High-throughput behavioral phenotyping of drug and alcohol susceptibility traits in the expanded panel of BXD recombinant inbred strains

    SciTech Connect

    Philip, Vivek M; Ansah, T; Blaha, C,; Cook, Melloni N.; Hamre, Kristin M.; Lariviere, William R; Matthews, Douglas B; Goldowitz, Daniel; Chesler, Elissa J

    2010-01-01

    Genetic reference populations, particularly the BXD recombinant inbred strains, are a valuable resource for the discovery of the bio-molecular substrates and genetic drivers responsible for trait variation and co- ariation. This approach can be profitably applied in the analysis of susceptibility and mechanisms of drug and alcohol use disorders for which many predisposing behaviors may predict occurrence and manifestation of increased preference for these substances. Many of these traits are modeled by common mouse behavioral assays, facilitating the detection of patterns and sources of genetic co-regulation of predisposing phenotypes and substance consumption. Members of the Tennessee Mouse Genome Consortium have obtained behavioral phenotype data from 260 measures related to multiple behavioral assays across several domains: self-administration, response to, and withdrawal from cocaine, MDMA, morphine and alcohol; novelty seeking; behavioral despair and related neurological phenomena; pain sensitivity; stress sensitivity; anxiety; hyperactivity; and sleep/wake cycles. All traits have been measured in both sexes and the recently expanded panel of 69 additional BXD recombinant inbred strains (N=69). Sex differences and heritability estimates were obtained for each trait, and a comparison of early (N = 32) and recent BXD RI lines was performed. Primary data is publicly available for heritability, sex difference and genetic analyses using www.GeneNetwork.org. These analyses include QTL detection and genetic analysis of gene expression. Stored results from these analyses are available at http://ontologicaldiscovery.org for comparison to other genomic analysis results. Together with the results of related studies, these data form a public resource for integrative systems genetic analysis of neurobehavioral traits.

  7. High throughput continuous cryopump

    SciTech Connect

    Foster, C.A.

    1986-01-01

    A cryocondensation pump with a unique regeneration mechanism that allows continuous operation has been constructed and tested. The pump features a device referred to as the ''Snail'' which removes the cryofrost layer as it is moved over the pumping surfaces. A forepump pumps the sublimed gas generated inside the Snail. The compression ratio of the pump is the ratio of the cryopump speed to the leakage conductance of the Snail. Deuterium had been pumped continuously at 30 torr.L/s at a speed of 2000 L/s and a compression ratio of 100. The pump, being all metal sealed and free of lubricating fluids, has many potential applications where untraclean high throughput pumping is desirable. Since the pump regenerates on a time scale of 60 seconds, the inventory in the pump is minimized - an important consideration when pumping radioactive materials such as tritium. Test data and a videotape of the Snail removing the cryofrost will be shown.

  8. High-Throughput Proteomics

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaorui; Wu, Si; Stenoien, David L.; Paša-Tolić, Ljiljana

    2014-06-01

    Mass spectrometry (MS)-based high-throughput proteomics is the core technique for large-scale protein characterization. Due to the extreme complexity of proteomes, sophisticated separation techniques and advanced MS instrumentation have been developed to extend coverage and enhance dynamic range and sensitivity. In this review, we discuss the separation and prefractionation techniques applied for large-scale analysis in both bottom-up (i.e., peptide-level) and top-down (i.e., protein-level) proteomics. Different approaches for quantifying peptides or intact proteins, including label-free and stable-isotope-labeling strategies, are also discussed. In addition, we present a brief overview of different types of mass analyzers and fragmentation techniques as well as selected emerging techniques.

  9. Altering Antimalarial Drug Regimens May Dramatically Enhance and Restore Drug Effectiveness.

    PubMed

    Kay, Katherine; Hodel, Eva Maria; Hastings, Ian M

    2015-10-01

    There is considerable concern that malaria parasites are starting to evolve resistance to the current generation of antimalarial drugs, the artemisinin-based combination therapies (ACTs). We use pharmacological modeling to investigate changes in ACT effectiveness likely to occur if current regimens are extended from 3 to 5 days or, alternatively, given twice daily over 3 days. We show that the pharmacology of artemisinins allows both regimen changes to substantially increase the artemisinin killing rate. Malaria patients rarely contain more than 10(12) parasites, while the standard dosing regimens allow approximately 1 in 10(10) parasites to survive artemisinin treatment. Parasite survival falls dramatically, to around 1 in 10(17) parasites if the dose is extended or split; theoretically, this increase in drug killing appears to be more than sufficient to restore failing ACT efficacy. One of the most widely used dosing regimens, artemether-lumefantrine, already successfully employs a twice-daily dosing regimen, and we argue that twice-daily dosing should be incorporated into all ACT regimen design considerations as a simple and effective way of ensuring the continued long-term effectiveness of ACTs. PMID:26239993

  10. Altering Antimalarial Drug Regimens May Dramatically Enhance and Restore Drug Effectiveness

    PubMed Central

    Hastings, Ian M.

    2015-01-01

    There is considerable concern that malaria parasites are starting to evolve resistance to the current generation of antimalarial drugs, the artemisinin-based combination therapies (ACTs). We use pharmacological modeling to investigate changes in ACT effectiveness likely to occur if current regimens are extended from 3 to 5 days or, alternatively, given twice daily over 3 days. We show that the pharmacology of artemisinins allows both regimen changes to substantially increase the artemisinin killing rate. Malaria patients rarely contain more than 1012 parasites, while the standard dosing regimens allow approximately 1 in 1010 parasites to survive artemisinin treatment. Parasite survival falls dramatically, to around 1 in 1017 parasites if the dose is extended or split; theoretically, this increase in drug killing appears to be more than sufficient to restore failing ACT efficacy. One of the most widely used dosing regimens, artemether-lumefantrine, already successfully employs a twice-daily dosing regimen, and we argue that twice-daily dosing should be incorporated into all ACT regimen design considerations as a simple and effective way of ensuring the continued long-term effectiveness of ACTs. PMID:26239993

  11. High-throughput screening platform for natural product-based drug discovery against 3 neglected tropical diseases: human African trypanosomiasis, leishmaniasis, and Chagas disease.

    PubMed

    Annang, F; Pérez-Moreno, G; García-Hernández, R; Cordon-Obras, C; Martín, J; Tormo, J R; Rodríguez, L; de Pedro, N; Gómez-Pérez, V; Valente, M; Reyes, F; Genilloud, O; Vicente, F; Castanys, S; Ruiz-Pérez, L M; Navarro, M; Gamarro, F; González-Pacanowska, D

    2015-01-01

    African trypanosomiasis, leishmaniasis, and Chagas disease are 3 neglected tropical diseases for which current therapeutic interventions are inadequate or toxic. There is an urgent need to find new lead compounds against these diseases. Most drug discovery strategies rely on high-throughput screening (HTS) of synthetic chemical libraries using phenotypic and target-based approaches. Combinatorial chemistry libraries contain hundreds of thousands of compounds; however, they lack the structural diversity required to find entirely novel chemotypes. Natural products, in contrast, are a highly underexplored pool of unique chemical diversity that can serve as excellent templates for the synthesis of novel, biologically active molecules. We report here a validated HTS platform for the screening of microbial extracts against the 3 diseases. We have used this platform in a pilot project to screen a subset (5976) of microbial extracts from the MEDINA Natural Products library. Tandem liquid chromatography-mass spectrometry showed that 48 extracts contain potentially new compounds that are currently undergoing de-replication for future isolation and characterization. Known active components included actinomycin D, bafilomycin B1, chromomycin A3, echinomycin, hygrolidin, and nonactins, among others. The report here is, to our knowledge, the first HTS of microbial natural product extracts against the above-mentioned kinetoplastid parasites.

  12. Development of high-throughput multi-residue method for non-steroidal anti-inflammatory drugs monitoring in swine muscle by LC-MS/MS.

    PubMed

    Castilhos, Tamara S; Barreto, Fabiano; Meneghini, Leonardo; Bergold, Ana Maria

    2016-07-01

    A reliable and simple method for the detection and quantification of residues of 14 non-steroidal anti-inflammatory drugs and a metamizole metabolite in swine muscle was developed using liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). The samples were extracted with acetonitrile (ACN) in solid-liquid extraction followed by a low-temperature partitioning (LLE-LTP) process at -20 ± 2°C. After evaporation to dryness, the residue was reconstituted with hexane and a mixture of water:acetonitrile (1:1). LC separation was achieved on a reversed-phase (RP18) column with gradient elution using water (phase A) and ACN (phase B) both containing 1 mmol l(-)(1) ammonium acetate (NH4COO) with 0.025% acetic acid. Analysis was carried out on a triple-quadrupole tandem mass spectrometer (LC-MS/MS) in multiple reaction monitoring mode using an electrospray interface in negative and positive mode in a single run. Method validation was performed according to the criteria of Commission Decision No. 2002/657/EC. The matrix effect and linearity were evaluated. Decision limit (CCα), detection capability (CCβ), accuracy and repeatability of the method are also reported. The proposed method proved to be simple, easy and adequate for high-throughput analysis and was applied to routine analysis by the Brazilian Ministry of Agriculture, Livestock and Food Supply. PMID:27268755

  13. The development and assessment of high-throughput mass spectrometry-based methods for the quantification of a nanoparticle drug delivery agent in cellular lysate.

    PubMed

    Buse, Joshua; Purves, Randy W; Verrall, Ronald E; Badea, Ildiko; Zhang, Haixia; Mulligan, Christopher C; Peru, Kerry M; Bailey, Jonathan; Headley, John V; El-Aneed, Anas

    2014-11-01

    The safe use of lipid-based drug delivery agents requires fast and sensitive qualitative and quantitative assessment of their cellular interactions. Many mass spectrometry (MS) based analytical platforms can achieve such task with varying capabilities. Therefore, four novel high-throughput MS-based quantitative methods were evaluated for the analysis of a small organic gene delivery agent: N,N-bis(dimethylhexadecyl)-1,3-propane-diammonium dibromide (G16-3). Analysis utilized MS instruments that detect analytes using low-resolution tandem MS (MS/MS) analysis (i.e. QTRAP or linear ion trap in this work) or high-resolution MS analysis (i.e. time of flight (ToF) or Orbitrap). Our results indicate that the validated fast chromatography (FC)-QTRAP-MS/MS, FC- LTQ-Orbitrap-MS, desorption electrospray ionization-collision-induced dissociation (CID)-MS/MS and matrix assisted laser desorption ionization-ToF/ToF-MS MS methods were superior in the area of method development and sample analysis time to a previously developed liquid chromatography (LC)-CID-MS/MS. To our knowledge, this is the first evaluation of the abilities of five MS-based quantitative methods that target a single pharmaceutical analyte. Our findings indicate that, in comparison to conventional LC-CID-MS/MS, the new MS-based methods resulted in a (1) substantial reduction in the analysis time, (2) reduction in the time required for method development and (3) production of either superior or comparable quantitative data. The four new high-throughput MS methods, therefore, were faster, more efficient and less expensive than a conventional LC-CID-MS/MS for the quantification of the G16-3 analyte within tissue culture. When applied to cellular lysate, no significant change in the concentration of G16-3 gemini surfactant within PAM212 cells was observed between 5 and 53 h, suggesting the absence of any metabolism/excretion from PAM212 cells.

  14. Chemical and genetic validation of thiamine utilization as an antimalarial drug target.

    PubMed

    Chan, Xie Wah Audrey; Wrenger, Carsten; Stahl, Katharina; Bergmann, Bärbel; Winterberg, Markus; Müller, Ingrid B; Saliba, Kevin J

    2013-01-01

    Thiamine is metabolized into an essential cofactor for several enzymes. Here we show that oxythiamine, a thiamine analog, inhibits proliferation of the malaria parasite Plasmodium falciparum in vitro via a thiamine-related pathway and significantly reduces parasite growth in a mouse malaria model. Overexpression of thiamine pyrophosphokinase (the enzyme that converts thiamine into its active form, thiamine pyrophosphate) hypersensitizes parasites to oxythiamine by up to 1,700-fold, consistent with oxythiamine being a substrate for thiamine pyrophosphokinase and its conversion into an antimetabolite. We show that parasites overexpressing the thiamine pyrophosphate-dependent enzymes oxoglutarate dehydrogenase and pyruvate dehydrogenase are up to 15-fold more resistant to oxythiamine, consistent with the antimetabolite inactivating thiamine pyrophosphate-dependent enzymes. Our studies therefore validate thiamine utilization as an antimalarial drug target and demonstrate that a single antimalarial can simultaneously target several enzymes located within distinct organelles.

  15. How Patients Take Malaria Treatment: A Systematic Review of the Literature on Adherence to Antimalarial Drugs

    PubMed Central

    Bruxvoort, Katia; Goodman, Catherine; Kachur, S. Patrick; Schellenberg, David

    2014-01-01

    Background High levels of patient adherence to antimalarial treatment are important in ensuring drug effectiveness. To achieve this goal, it is important to understand levels of patient adherence, and the range of study designs and methodological challenges involved in measuring adherence and interpreting results. Since antimalarial adherence was reviewed in 2004, there has been a major expansion in the use of artemisinin-based combination therapies (ACTs) in the public sector, as well as initiatives to make them more widely accessible through community health workers and private retailers. These changes and the large number of recent adherence studies raise the need for an updated review on this topic. Objective We conducted a systematic review of studies reporting quantitative results on patient adherence to antimalarials obtained for treatment. Results The 55 studies identified reported extensive variation in patient adherence to antimalarials, with many studies reporting very high adherence (90–100%) and others finding adherence of less than 50%. We identified five overarching approaches to assessing adherence based on the definition of adherence and the methods used to measure it. Overall, there was no clear pattern in adherence results by approach. However, adherence tended to be higher among studies where informed consent was collected at the time of obtaining the drug, where patient consultations were directly observed by research staff, and where a diagnostic test was obtained. Conclusion Variations in reported adherence may reflect factors related to patient characteristics and the nature of their consultation with the provider, as well as methodological variations such as interaction between the research team and patients before and during the treatment. Future studies can benefit from an awareness of the impact of study procedures on adherence outcomes, and the identification of improved measurement methods less dependent on self-report. PMID:24465418

  16. High-throughput proteomics

    NASA Astrophysics Data System (ADS)

    Lesley, Scott A.; Nasoff, Marc; Kreusch, Andreas; Spraggon, Glen

    2001-04-01

    Proteomics has become a major focus as researchers attempt to understand the vast amount of genomic information. Protein complexity makes identifying and understanding gene function inherently difficult. The challenge of studying proteins in a global way is driving the development of new technologies for systematic and comprehensive analysis of protein structure and function. We are addressing this challenge through instrumentation and approaches to rapidly express, purify, crystallize, and mutate large numbers of human gene products. Our approach applies the principles of HTS technologies commonly used in pharmaceutical development. Genes are cloned, expressed, and purified in parallel to achieve a throughput potential of hundreds per day. Our instrumentation allows us to produce tens of milligrams of protein from 96 separate clones simultaneously. Purified protein is used for several applications including a high-throughput crystallographic screening approach for structure determination using automated image analysis. To further understand protein function, we are integrating a mutagenesis and screening approach. By combining these key technologies, we hope to provide a fundamental basis for understanding gene function at the protein level.

  17. High throughput optical scanner

    DOEpatents

    Basiji, David A.; van den Engh, Gerrit J.

    2001-01-01

    A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector. For phase-sensitive detection the light source is intensity modulated and the detector is connected to phase-sensitive detection electronics. A scanner using a substrate translator is also provided. For two dimensional imaging the substrate is translated in one dimension while the scanning mirror scans the beam in a second dimension. For a high throughput scanner, stacks of substrates are loaded onto a conveyor belt from a tray feeder.

  18. Antimalarial Drug Discovery: Approaches and Progress towards New Medicines

    PubMed Central

    Flannery, Erika L.; Chatterjee, Arnab K.; Winzeler, Elizabeth A.

    2014-01-01

    Malaria elimination has recently been reinstated as a global health priority but current therapies seem to be insufficient for the task. Elimination efforts require new drug classes that alleviate symptoms, prevent transmission and provide a radical cure. To develop these next generation medicines, public-private partnerships are funding innovative approaches to identify compounds that target multiple parasite species at multiple stages of the parasite lifecycle. Here, we review the cell-, chemistry- and target-based approaches used to discover new drug candidates that are currently in clinical trials or undergoing preclinical testing. PMID:24217412

  19. Measuring Topology of Low-Intensity DNA Methylation Sites for High Throughput Assessment of Epigenetic Drug-Induced Effects in Cancer Cells

    PubMed Central

    Gertych, Arkadiusz; Farkas, Daniel L.; Tajbakhsh, Jian

    2010-01-01

    component in the high throughput assessment of demethylation and risk of chromatin reorganization in epigenetic-drug screening tasks. PMID:20813111

  20. Measuring topology of low-intensity DNA methylation sites for high-throughput assessment of epigenetic drug-induced effects in cancer cells

    SciTech Connect

    Gertych, Arkadiusz; Farkas, Daniel L.; Tajbakhsh, Jian

    2010-11-15

    potentially be a valuable component in the high-throughput assessment of demethylation and risk of chromatin reorganization in epigenetic-drug screening tasks.

  1. Study of the efficacy of antimalarial drugs delivered inside targeted immunoliposomal nanovectors

    NASA Astrophysics Data System (ADS)

    Urbán, Patricia; Estelrich, Joan; Adeva, Alberto; Cortés, Alfred; Fernàndez-Busquets, Xavier

    2011-12-01

    Paul Ehrlich's dream of a 'magic bullet' that would specifically destroy invading microbes is now a major aspect of clinical medicine. However, a century later, the implementation of this medical holy grail continues being a challenge in three main fronts: identifying the right molecular or cellular targets for a particular disease, having a drug that is effective against it, and finding a strategy for the efficient delivery of sufficient amounts of the drug in an active state exclusively to the selected targets. In a previous work, we engineered an immunoliposomal nanovector for the targeted delivery of its contents exclusively to Plasmodium falciparum-infected red blood cells [pRBCs]. In preliminary assays, the antimalarial drug chloroquine showed improved efficacy when delivered inside immunoliposomes targeted with the pRBC-specific monoclonal antibody BM1234. Because difficulties in determining the exact concentration of the drug due to its low amounts prevented an accurate estimation of the nanovector performance, here, we have developed an HPLC-based method for the precise determination of the concentrations in the liposomal preparations of chloroquine and of a second antimalarial drug, fosmidomycin. The results obtained indicate that immunoliposome encapsulation of chloroquine and fosmidomycin improves by tenfold the efficacy of antimalarial drugs. The targeting antibody used binds preferentially to pRBCs containing late maturation stages of the parasite. In accordance with this observation, the best performing immunoliposomes are those added to Plasmodium cultures having a larger number of late form-containing pRBCs. An average of five antibody molecules per liposome significantly improves in cell cultures the performance of immunoliposomes over non-functionalized liposomes as drug delivery vessels. Increasing the number of antibodies on the liposome surface correspondingly increases performance, with a reduction of 50% parasitemia achieved with

  2. The Interactions of P-Glycoprotein with Antimalarial Drugs, Including Substrate Affinity, Inhibition and Regulation.

    PubMed

    Senarathna, S M D K Ganga; Page-Sharp, Madhu; Crowe, Andrew

    2016-01-01

    The combination of passive drug permeability, affinity for uptake and efflux transporters as well as gastrointestinal metabolism defines net drug absorption. Efflux mechanisms are often overlooked when examining the absorption phase of drug bioavailability. Knowing the affinity of antimalarials for efflux transporters such as P-glycoprotein (P-gp) may assist in the determination of drug absorption and pharmacokinetic drug interactions during oral absorption in drug combination therapies. Concurrent administration of P-gp inhibitors and P-gp substrate drugs may also result in alterations in the bioavailability of some antimalarials. In-vitro Caco-2 cell monolayers were used here as a model for potential drug absorption related problems and P-gp mediated transport of drugs. Artemisone had the highest permeability at around 50 x 10(-6) cm/sec, followed by amodiaquine around 20 x 10(-6) cm/sec; both mefloquine and artesunate were around 10 x 10(-6) cm/sec. Methylene blue was between 2 and 6 x 10(-6) cm/sec depending on the direction of transport. This 3 fold difference was able to be halved by use of P-gp inhibition. MRP inhibition also assisted the consolidation of the methylene blue transport. Mefloquine was shown to be a P-gp inhibitor affecting our P-gp substrate, Rhodamine 123, although none of the other drugs impacted upon rhodamine123 transport rates. In conclusion, mefloquine is a P-gp inhibitor and methylene blue is a partial substrate; methylene blue may have increased absorption if co-administered with such P-gp inhibitors. An upregulation of P-gp was observed when artemisone and dihydroartemisinin were co-incubated with mefloquine and amodiaquine. PMID:27045516

  3. The Interactions of P-Glycoprotein with Antimalarial Drugs, Including Substrate Affinity, Inhibition and Regulation.

    PubMed

    Senarathna, S M D K Ganga; Page-Sharp, Madhu; Crowe, Andrew

    2016-01-01

    The combination of passive drug permeability, affinity for uptake and efflux transporters as well as gastrointestinal metabolism defines net drug absorption. Efflux mechanisms are often overlooked when examining the absorption phase of drug bioavailability. Knowing the affinity of antimalarials for efflux transporters such as P-glycoprotein (P-gp) may assist in the determination of drug absorption and pharmacokinetic drug interactions during oral absorption in drug combination therapies. Concurrent administration of P-gp inhibitors and P-gp substrate drugs may also result in alterations in the bioavailability of some antimalarials. In-vitro Caco-2 cell monolayers were used here as a model for potential drug absorption related problems and P-gp mediated transport of drugs. Artemisone had the highest permeability at around 50 x 10(-6) cm/sec, followed by amodiaquine around 20 x 10(-6) cm/sec; both mefloquine and artesunate were around 10 x 10(-6) cm/sec. Methylene blue was between 2 and 6 x 10(-6) cm/sec depending on the direction of transport. This 3 fold difference was able to be halved by use of P-gp inhibition. MRP inhibition also assisted the consolidation of the methylene blue transport. Mefloquine was shown to be a P-gp inhibitor affecting our P-gp substrate, Rhodamine 123, although none of the other drugs impacted upon rhodamine123 transport rates. In conclusion, mefloquine is a P-gp inhibitor and methylene blue is a partial substrate; methylene blue may have increased absorption if co-administered with such P-gp inhibitors. An upregulation of P-gp was observed when artemisone and dihydroartemisinin were co-incubated with mefloquine and amodiaquine.

  4. The Interactions of P-Glycoprotein with Antimalarial Drugs, Including Substrate Affinity, Inhibition and Regulation

    PubMed Central

    Senarathna, S M D K Ganga; Page-Sharp, Madhu; Crowe, Andrew

    2016-01-01

    The combination of passive drug permeability, affinity for uptake and efflux transporters as well as gastrointestinal metabolism defines net drug absorption. Efflux mechanisms are often overlooked when examining the absorption phase of drug bioavailability. Knowing the affinity of antimalarials for efflux transporters such as P-glycoprotein (P-gp) may assist in the determination of drug absorption and pharmacokinetic drug interactions during oral absorption in drug combination therapies. Concurrent administration of P-gp inhibitors and P-gp substrate drugs may also result in alterations in the bioavailability of some antimalarials. In-vitro Caco-2 cell monolayers were used here as a model for potential drug absorption related problems and P-gp mediated transport of drugs. Artemisone had the highest permeability at around 50 x 10−6 cm/sec, followed by amodiaquine around 20 x 10−6 cm/sec; both mefloquine and artesunate were around 10 x 10−6 cm/sec. Methylene blue was between 2 and 6 x 10−6 cm/sec depending on the direction of transport. This 3 fold difference was able to be halved by use of P-gp inhibition. MRP inhibition also assisted the consolidation of the methylene blue transport. Mefloquine was shown to be a P-gp inhibitor affecting our P-gp substrate, Rhodamine 123, although none of the other drugs impacted upon rhodamine123 transport rates. In conclusion, mefloquine is a P-gp inhibitor and methylene blue is a partial substrate; methylene blue may have increased absorption if co-administered with such P-gp inhibitors. An upregulation of P-gp was observed when artemisone and dihydroartemisinin were co-incubated with mefloquine and amodiaquine. PMID:27045516

  5. Why Hospital Pharmacists Have Failed to Manage Antimalarial Drugs Stock-Outs in Pakistan? A Qualitative Insight

    PubMed Central

    Hassali, Mohamed Azmi Ahmad; Shafie, Asrul Akmal; Hussain, Azhar

    2013-01-01

    Purpose. This study aimed to explore the perceptions of hospital pharmacists towards drug management and reasons underlying stock-outs of antimalarial drugs in Pakistan. Methods. A qualitative study was designed to explore the perceptions of hospital pharmacists regarding drug management and irrational use of antimalarial drugs in two major cities of Pakistan, namely, Islamabad (national capital) and Rawalpindi (twin city). Semistructured interviews were conducted with 16 hospital pharmacists using indepth interview guides at a place and time convenient for the respondents. Interviews, which were audiotaped and transcribed verbatim, were evaluated by thematic content analysis and by other authors' analysis. Results. Most of the respondents were of the view that financial constraints, inappropriate drug management, and inadequate funding were the factors contributing toward the problem of antimalarial drug stock-outs in healthcare facilities of Pakistan. The pharmacists anticipated that prescribing by nonproprietary names, training of health professionals, accepted role of hospital pharmacist in drug management, implementation of essential drug list and standard treatment guidelines for malaria in the healthcare system can minimize the problem of drug stock outs in healthcare system of Pakistan. Conclusion. The current study showed that all the respondents in the two cities agreed that hospital pharmacist has failed to play an effective role in efficient management of anti-malarial drugs stock-outs. PMID:24223321

  6. Policy options for deploying anti-malarial drugs in endemic countries: a population genetics approach

    PubMed Central

    2012-01-01

    Background Anti-malarial drugs are constantly exposed to the threat of evolving drug resistance so good stewardship of existing therapy is an essential component of public health policy. However, the widespread availability of numerous different drugs through informal providers could undermine official drug deployment policies. A policy of multiple first-line therapy (MFT) is compared with the conventional policy of sequential drug deployment, i.e., where one drug is used until resistance evolves and then replaced by the next drug in the sequence. Methods Population genetic models of drug resistance are used to make the comparison; this methodology explicitly tracks the genetics of drug resistance (including, importantly, recombination in the sexual stage, intrahost dynamics, and direction of linkage disequilibrium). Results A policy of MFT outlasts sequential application providing drug usages are low to moderate, and appears not to drive widespread multi-drug resistance. Inadequate dosing is an even more potent driver of drug resistance than the MFT/sequential policy decision. Conclusions The provision of MFT as a deliberate policy can be encouraged provided overall treatment rates are low or moderate (less than around half of malaria infections are treated) and the ad hoc provision of MFT through the private sector may be tolerated. This must be fully supported by education to ensure people take adequate doses of each of the drugs. PMID:23244624

  7. Antimalarial drug resistance: a review of the biology and strategies to delay emergence and spread

    PubMed Central

    Klein, E.Y.

    2013-01-01

    The emergence of resistance to former first-line antimalarial drugs has been an unmitigated disaster. In recent years, artemisinin class drugs have become standard and they are considered an essential tool for helping to eradicate the disease. However, their ability to reduce morbidity and mortality and to slow transmission requires the maintenance of effectiveness. Recently, an artemisinin delayed-clearance phenotype was described. This is believed to be the precursor to resistance and threatens local elimination and global eradication plans. Understanding how resistance emerges and spreads is important for developing strategies to contain its spread. Resistance is the result of two processes: (i) drug selection of resistant parasites; and (ii) the spread of resistance. In this review, we examine the factors that lead to both drug selection and the spread of resistance. We then examine strategies for controlling the spread of resistance, pointing out the complexities and deficiencies in predicting how resistance will spread. PMID:23394809

  8. Interaction of quinoline antimalarial drugs with ferriprotoporphyrin IX, a solid state spectroscopy study.

    PubMed

    Asghari-Khiavi, Mehdi; Vongsvivut, Jitraporn; Perepichka, Inna; Mechler, Adam; Wood, Bayden R; McNaughton, Don; Bohle, D Scott

    2011-12-01

    To investigate the nature of binding of quinoline antimalarial drugs to heme and to extract experimental evidence for this binding, the interaction of ferriprotoporphyrin IX (FP) with chloroquine and quinacrine (both of which have a similar side chain) and quinoline methanol antimalarials quinine and mefloquine has been studied using IR and NIR-Raman spectroscopy in the solid state. Attenuated total reflectance infrared spectroscopic data clearly show that heme in chloroquine-FP complex is not μ-oxo dimeric indicating that the hypothesis that chloroquine binds to FP μ-oxo dimer with a stoichiometry of 1 chloroquine:2 μ-oxo dimers is not valid in the solid state. Moreover, the first vibrational spectroscopy evidence is presented for the formation of hydrogen bonding between a propionate group of heme and the tertiary amino nitrogen of chloroquine and quinacrine. Raman spectroscopy data does not provide any evidence to support the formation of a similar salt bridge in the complexes of FP with quinine and mefloquine; however, it suggests that the interaction of these drugs with FP happens through coordination of the Fe(III) center of the porphyrin to the 9-hydroxy group of the drug.

  9. Chemogenomic profiling of Plasmodium falciparum as a tool to aid antimalarial drug discovery.

    PubMed

    Pradhan, Anupam; Siwo, Geoffrey H; Singh, Naresh; Martens, Brian; Balu, Bharath; Button-Simons, Katrina A; Tan, Asako; Zhang, Min; Udenze, Kenneth O; Jiang, Rays H Y; Ferdig, Michael T; Adams, John H; Kyle, Dennis E

    2015-01-01

    The spread of Plasmodium falciparum multidrug resistance highlights the urgency to discover new targets and chemical scaffolds. Unfortunately, lack of experimentally validated functional information about most P. falciparum genes remains a strategic hurdle. Chemogenomic profiling is an established tool for classification of drugs with similar mechanisms of action by comparing drug fitness profiles in a collection of mutants. Inferences of drug mechanisms of action and targets can be obtained by associations between shifts in drug fitness and specific genetic changes in the mutants. In this screen, P. falciparum, piggyBac single insertion mutants were profiled for altered responses to antimalarial drugs and metabolic inhibitors to create chemogenomic profiles. Drugs targeting the same pathway shared similar response profiles and multiple pairwise correlations of the chemogenomic profiles revealed novel insights into drugs' mechanisms of action. A mutant of the artemisinin resistance candidate gene - "K13-propeller" gene (PF3D7_1343700) exhibited increased susceptibility to artemisinin drugs and identified a cluster of 7 mutants based on similar enhanced responses to the drugs tested. Our approach of chemogenomic profiling reveals artemisinin functional activity, linked by the unexpected drug-gene relationships of these mutants, to signal transduction and cell cycle regulation pathways.

  10. Network medicine and high throughput screening.

    PubMed

    Smith, Robert E; Tran, Kevin; Vocque, Ralph H

    2013-09-01

    A new paradigm is emerging in modern drug discovery. It is a fusion of traditional and modern medicine, phenotypic and targeted drug discovery, or systems and reductionist thinking. This is exemplified by using a combination of network medicine and high throughput screening. It blends the use of physiologically relevant biological systems with the high throughput and statistical robustness of modern assay technologies. The basic principles of network theory and tools of network medicine are described. Scale-free networks and their organizing principles are discussed. They are emergent properties of living, autopoietic systems. This includes networks of people who do high throughput screening (HTS), and microscopic networks of ions, metabolites, DNA, RNA, proteins, lipids, carbohydrates, viruses, bacteria, fungi, human cells and tissues. Databases have been constructed based on the metabolome, genome, transcriptome, proteome, lipidome, glycocode, virome, bacteriome and many others. Modern HTS can be used to examine the interactions of many parts of the complex human network. High content screening (HCS) can look at perturbations that occur when test compounds are added to single cells. Allo-network drugs can have effects far beyond a single protein and can be transmitted to other cells. Interactions and hidden connections can be revealed, with the goal of developing new drugs that have few, if any harmful side effects and are effective against multi-drug resistant cancer cells or bacteria.

  11. Antimalarial Drug Quality in the Most Severely Malarious Parts of Africa – A Six Country Study

    PubMed Central

    Bate, Roger; Coticelli, Philip; Tren, Richard; Attaran, Amir

    2008-01-01

    A range of antimalarial drugs were procured from private pharmacies in urban and peri-urban areas in the major cities of six African countries, situated in the part of that continent and the world that is most highly endemic for malaria. Semi-quantitative thin-layer chromatography (TLC) and dissolution testing were used to measure active pharmaceutical ingredient content against internationally acceptable standards. 35% of all samples tested failed either or both tests, and were substandard. Further, 33% of treatments collected were artemisinin monotherapies, most of which (78%) were manufactured in disobservance of an appeal by the World Health Organisation (WHO) to withdraw these clinically inappropriate medicines from the market. The high persistence of substandard drugs and clinically inappropriate artemisinin monotherapies in the private sector risks patient safety and, through drug resistance, places the future of malaria treatment at risk globally. PMID:18461128

  12. Anti-malarial Drugs Primaquine and Chloroquine Have Different Sensitization Effects with Anti-mitotic Drugs in Resistant Cancer Cells.

    PubMed

    Choi, Ae-Ran; Kim, Ju-Hwa; Woo, Yeon Hwa; Kim, Hyung Sik; Yoon, Sungpil

    2016-04-01

    The purpose of this study was to identify conditions that would increase the sensitivity of drug-resistant cancer cells. Previously, two anti-malarial drugs, chloroquine (CHL) and primaquine (PRI), showed different sensitization effects for vinblastine (VIB)-resistant cancer cells. Herein, we tested co-treatment of cells with CHL or PRI and other microtubule-targeting cancer drugs, namely, vinorelbine (VIO), paclitaxel (PAC), docetaxel (DOC), vincristine (VIC), or halaven (HAL). We found that PRI sensitized P-glycoprotein (P-gp)-overexpressing drug-resistant KBV20C cells to all six anti-mitotic drugs to a similar extent. CHL had a similar sensitization effect only for co-treatment with PAC, DOC, VIC, and HAL, while the sensitization effect was less marked for co-treatment with VIB or VIO. FACS analysis and western blot analysis revealed that G2arrest and apoptosis showed only a slight increase on co-treatment with VIB or VIO and CHL. We also found that phospho-histone H3 and pRb were markedly increased only by PRI-VIB co-treatment, but not by CHL-VIB co-treatment. This suggests that reduction in the expression of these proteins correlates with decreased G2arrest in CHL-VIB co-treatment. We further compared the effect of another anti-malarial drug, mefloquine (MEF), in combination with the six anti-mitotic drugs. We found that MEF and PRI had similar sensitization effects in co-treatment with these anti-mitotic drugs. PRI and MEF had generally similar sensitization effects in co-treatment with anti-mitotic drugs, suggesting that they do not have any preferred anti-mitotic drug partner in co-treatment. This indicates that only CHL shows specificity in co-treatment with anti-mitotic drugs in resistant cancer cells. Our results may contribute to the choice of anti-mitotic drugs to be used in co-treatment of resistant cancer cells with the anti-malarial drugs, CHL, PRI, and MEF. PMID:27069141

  13. Chemogenomic profiling of Plasmodium falciparum as a tool to aid antimalarial drug discovery

    PubMed Central

    Pradhan, Anupam; Siwo, Geoffrey H.; Singh, Naresh; Martens, Brian; Balu, Bharath; Button-Simons, Katrina A.; Tan, Asako; Zhang, Min; Udenze, Kenneth O.; Jiang, Rays H.Y.; Ferdig, Michael T.; Adams, John H.; Kyle, Dennis E.

    2015-01-01

    The spread of Plasmodium falciparum multidrug resistance highlights the urgency to discover new targets and chemical scaffolds. Unfortunately, lack of experimentally validated functional information about most P. falciparum genes remains a strategic hurdle. Chemogenomic profiling is an established tool for classification of drugs with similar mechanisms of action by comparing drug fitness profiles in a collection of mutants. Inferences of drug mechanisms of action and targets can be obtained by associations between shifts in drug fitness and specific genetic changes in the mutants. In this screen, P. falciparum, piggyBac single insertion mutants were profiled for altered responses to antimalarial drugs and metabolic inhibitors to create chemogenomic profiles. Drugs targeting the same pathway shared similar response profiles and multiple pairwise correlations of the chemogenomic profiles revealed novel insights into drugs’ mechanisms of action. A mutant of the artemisinin resistance candidate gene - “K13-propeller” gene (PF3D7_1343700) exhibited increased susceptibility to artemisinin drugs and identified a cluster of 7 mutants based on similar enhanced responses to the drugs tested. Our approach of chemogenomic profiling reveals artemisinin functional activity, linked by the unexpected drug-gene relationships of these mutants, to signal transduction and cell cycle regulation pathways. PMID:26541648

  14. Understanding the biology of the Plasmodium falciparum apicoplast; an excellent target for antimalarial drug development.

    PubMed

    Chakraborty, Arnish

    2016-08-01

    Malaria is a life-threatening tropical disease, caused by the intracellular parasite Plasmodium falciparum. The World Health Organization counts malaria as one of the top ten causes of worldwide death. The unavailability of a successful malaria vaccine and the ever-increasing instances of drug resistance in the malaria parasite demand the discovery of new targets within P. falciparum for the development of next generation antimalarials. Fortunately, all apicomplexan parasites, including P. falciparum harbor a relict, non-photosynthetic plastid known as the apicoplast. The apicoplast is a semi-autonomous organelle within P. falciparum containing a 35kb circular genome. Despite a genome of its own, majority of the apicoplast proteins are encoded by the parasite nucleus and imported into the apicoplast. The organelle has been shown to be essential to P. falciparum survival and the loss the apicoplast manifests as a 'delayed death' response in the parasite. The apicoplast has evolved out of cyanobacteria in a complex, two step endosymbiotic event. As a result the architecture and the gene expression machinery of the apicoplast is quite bacteria-like and is susceptible to a wide range of antibiotics such as fosmidomycin, tetracycline, azithromycin, clindamycin and triclosan. The biosynthetic pathways for isoprenoids, fatty acids and heme operate within the malaria apicoplast, making the organelle an excellent target for drug development. The review focuses on the evolution, biology and the essentiality of the apicoplast within the malaria parasite and discusses some of the recent achievements towards the design and discovery of apicoplast targeted antimalarial compounds.

  15. Discovery and Characterization of ACT-451840: an Antimalarial Drug with a Novel Mechanism of Action.

    PubMed

    Boss, Christoph; Aissaoui, Hamed; Amaral, Nathalie; Bauer, Aude; Bazire, Stephanie; Binkert, Christoph; Brun, Reto; Bürki, Cédric; Ciana, Claire-Lise; Corminboeuf, Olivier; Delahaye, Stephane; Dollinger, Claire; Fischli, Christoph; Fischli, Walter; Flock, Alexandre; Frantz, Marie-Céline; Girault, Malory; Grisostomi, Corinna; Friedli, Astrid; Heidmann, Bibia; Hinder, Claire; Jacob, Gael; Le Bihan, Amelie; Malrieu, Sophie; Mamzed, Saskia; Merot, Aurelien; Meyer, Solange; Peixoto, Sabrina; Petit, Nolwenn; Siegrist, Romain; Trollux, Julien; Weller, Thomas; Wittlin, Sergio

    2016-09-20

    More than 40 % of the world's population is at risk of being infected with malaria. Most malaria cases occur in the countries of sub-Saharan Africa, Central and South America, and Asia. Resistance to standard therapy, including artemisinin combinations, is increasing. There is an urgent need for novel antimalarials with new mechanisms of action. In a phenotypic screen, we identified a series of phenylalanine-based compounds that exhibit antimalarial activity via a new and yet unknown mechanism of action. Our optimization efforts culminated in the selection of ACT-451840 [(S,E)-N-(4-(4-acetylpiperazin-1-yl)benzyl)-3-(4-(tert-butyl)phenyl)-N-(1-(4-(4-cyanobenzyl)piperazin-1-yl)-1-oxo-3-phenylpropan-2-yl)acrylamide] for clinical development. Herein we describe our optimization efforts from the screening hit to the potential drug candidate with respect to antiparasitic activity, drug metabolism and pharmacokinetics (DMPK) properties, and in vivo pharmacological efficacy.

  16. 2D Inorganic-Antimalarial Drug-Polymer Hybrid with pH-Responsive Solubility.

    PubMed

    Kim, Ji-Yeong; Yang, Jae-Hun; Lee, Ji-Hee; Choi, Goeun; Park, Dae-Hwan; Jo, Mi-Rea; Choi, Soo-Jin; Choy, Jin-Ho

    2015-10-01

    Artesunic acid (ASH), an antimalarial drug, has low oral bioavailability due to its low aqueous solubility. To overcome this problem, artesunate (AS) was intercalated into zinc basic salt (ZBS) via co-precipitation. AS was immobilized with a tilted double layer arrangement, which was also confirmed by XRD and 1-D electron density mapping. In order to decrease the release rate of AS under gastrointestinal conditions and to simultaneously increase the release rate of AS under intestinal conditions, ZBS-AS was coated with EUDRAGIT L100 (ZBS-AS-L100). Finally, we performed an in-vivo pharmacokinetic study to compare the oral bioavailability of AS of ZBS-AS-L100 with that of ASH. Surprisingly, it was found that the former is 5.5 times greater than the latter due to an enhanced solubility of AS thanks to the ternary hybridization with ZBS and EUDRAGIT L100. Therefore, the present ZBS-AS-L100 system has a great potential as a novel antimalarial drug formulation with pH selectivity and enhanced bioavailability.

  17. CRIMALDDI: a co-ordinated, rational, and integrated effort to set logical priorities in anti-malarial drug discovery initiatives

    PubMed Central

    2010-01-01

    Despite increasing efforts and support for anti-malarial drug R&D, globally anti-malarial drug discovery and development remains largely uncoordinated and fragmented. The current window of opportunity for large scale funding of R&D into malaria is likely to narrow in the coming decade due to a contraction in available resources caused by the current economic difficulties and new priorities (e.g. climate change). It is, therefore, essential that stakeholders are given well-articulated action plans and priorities to guide judgments on where resources can be best targeted. The CRIMALDDI Consortium (a European Union funded initiative) has been set up to develop, through a process of stakeholder and expert consultations, such priorities and recommendations to address them. It is hoped that the recommendations will help to guide the priorities of the European anti-malarial research as well as the wider global discovery agenda in the coming decade. PMID:20626844

  18. Molecular Farming in Artemisia annua, a Promising Approach to Improve Anti-malarial Drug Production

    PubMed Central

    Pulice, Giuseppe; Pelaz, Soraya; Matías-Hernández, Luis

    2016-01-01

    Malaria is a parasite infection affecting millions of people worldwide. Even though progress has been made in prevention and treatment of the disease; an estimated 214 million cases of malaria occurred in 2015, resulting in 438,000 estimated deaths; most of them occurring in Africa among children under the age of five. This article aims to review the epidemiology, future risk factors and current treatments of malaria, with particular focus on the promising potential of molecular farming that uses metabolic engineering in plants as an effective anti-malarial solution. Malaria represents an example of how a health problem may, on one hand, influence the proper development of a country, due to its burden of the disease. On the other hand, it constitutes an opportunity for lucrative business of diverse stakeholders. In contrast, plant biofarming is proposed here as a sustainable, promising, alternative for the production, not only of natural herbal repellents for malaria prevention but also for the production of sustainable anti-malarial drugs, like artemisinin (AN), used for primary parasite infection treatments. AN, a sesquiterpene lactone, is a natural anti-malarial compound that can be found in Artemisia annua. However, the low concentration of AN in the plant makes this molecule relatively expensive and difficult to produce in order to meet the current worldwide demand of Artemisinin Combination Therapies (ACTs), especially for economically disadvantaged people in developing countries. The biosynthetic pathway of AN, a process that takes place only in glandular secretory trichomes of A. annua, is relatively well elucidated. Significant efforts have been made using plant genetic engineering to increase production of this compound. These include diverse genetic manipulation approaches, such as studies on diverse transcription factors which have been shown to regulate the AN genetic pathway and other biological processes. Results look promising; however, further

  19. Molecular Farming in Artemisia annua, a Promising Approach to Improve Anti-malarial Drug Production.

    PubMed

    Pulice, Giuseppe; Pelaz, Soraya; Matías-Hernández, Luis

    2016-01-01

    Malaria is a parasite infection affecting millions of people worldwide. Even though progress has been made in prevention and treatment of the disease; an estimated 214 million cases of malaria occurred in 2015, resulting in 438,000 estimated deaths; most of them occurring in Africa among children under the age of five. This article aims to review the epidemiology, future risk factors and current treatments of malaria, with particular focus on the promising potential of molecular farming that uses metabolic engineering in plants as an effective anti-malarial solution. Malaria represents an example of how a health problem may, on one hand, influence the proper development of a country, due to its burden of the disease. On the other hand, it constitutes an opportunity for lucrative business of diverse stakeholders. In contrast, plant biofarming is proposed here as a sustainable, promising, alternative for the production, not only of natural herbal repellents for malaria prevention but also for the production of sustainable anti-malarial drugs, like artemisinin (AN), used for primary parasite infection treatments. AN, a sesquiterpene lactone, is a natural anti-malarial compound that can be found in Artemisia annua. However, the low concentration of AN in the plant makes this molecule relatively expensive and difficult to produce in order to meet the current worldwide demand of Artemisinin Combination Therapies (ACTs), especially for economically disadvantaged people in developing countries. The biosynthetic pathway of AN, a process that takes place only in glandular secretory trichomes of A. annua, is relatively well elucidated. Significant efforts have been made using plant genetic engineering to increase production of this compound. These include diverse genetic manipulation approaches, such as studies on diverse transcription factors which have been shown to regulate the AN genetic pathway and other biological processes. Results look promising; however, further

  20. Holographic analysis on deformation and restoration of malaria-infected red blood cells by antimalarial drug

    NASA Astrophysics Data System (ADS)

    Byeon, Hyeokjun; Ha, Young-Ran; Lee, Sang Joon

    2015-11-01

    Malaria parasites induce morphological, biochemical, and mechanical changes in red blood cells (RBCs). Mechanical variations are closely related to the deformability of individual RBCs. The deformation of various RBCs, including healthy and malaria-infected RBCs (iRBCs), can be directly observed through quantitative phase imaging (QPI). The effects of chloroquine treatment on the mechanical property variation of iRBCs were investigated using time-resolved holographic QPI of single live cells on a millisecond time scale. The deformabilities of healthy RBCs, iRBCs, and drug-treated iRBCs were compared, and the effect of chloroquine on iRBC restoration was experimentally examined. The present results are beneficial to elucidate the dynamic characteristics of iRBCs and the effect of the antimalarial drug on iRBCs.

  1. A novel asymmetric-loop molecular beacon-based two-phase hybridization assay for accurate and high-throughput detection of multiple drug resistance-conferring point mutations in Mycobacterium tuberculosis.

    PubMed

    Chen, Qinghai; Wu, Nan; Xie, Meng; Zhang, Bo; Chen, Ming; Li, Jianjun; Zhuo, Lisha; Kuang, Hong; Fu, Weiling

    2012-04-01

    The accurate and high-throughput detection of drug resistance-related multiple point mutations remains a challenge. Although the combination of molecular beacons with bio-immobilization technology, such as microarray, is promising, its application is difficult due to the ineffective immobilization of molecular beacons on the chip surface. Here, we propose a novel asymmetric-loop molecular beacon in which the loop consists of 2 parts. One is complementary to a target, while the other is complementary to an oligonucleotide probe immobilized on the chip surface. With this novel probe, a two-phase hybridization assay can be used for simultaneously detecting multiple point mutations. This assay will have advantages, such as easy probe availability, multiplex detection, low background, and high-efficiency hybridization, and may provide a new avenue for the immobilization of molecular beacons and high-throughput detection of point mutations.

  2. Validation of N-myristoyltransferase as an antimalarial drug target using an integrated chemical biology approach

    NASA Astrophysics Data System (ADS)

    Wright, Megan H.; Clough, Barbara; Rackham, Mark D.; Rangachari, Kaveri; Brannigan, James A.; Grainger, Munira; Moss, David K.; Bottrill, Andrew R.; Heal, William P.; Broncel, Malgorzata; Serwa, Remigiusz A.; Brady, Declan; Mann, David J.; Leatherbarrow, Robin J.; Tewari, Rita; Wilkinson, Anthony J.; Holder, Anthony A.; Tate, Edward W.

    2014-02-01

    Malaria is an infectious disease caused by parasites of the genus Plasmodium, which leads to approximately one million deaths per annum worldwide. Chemical validation of new antimalarial targets is urgently required in view of rising resistance to current drugs. One such putative target is the enzyme N-myristoyltransferase, which catalyses the attachment of the fatty acid myristate to protein substrates (N-myristoylation). Here, we report an integrated chemical biology approach to explore protein myristoylation in the major human parasite P. falciparum, combining chemical proteomic tools for identification of the myristoylated and glycosylphosphatidylinositol-anchored proteome with selective small-molecule N-myristoyltransferase inhibitors. We demonstrate that N-myristoyltransferase is an essential and chemically tractable target in malaria parasites both in vitro and in vivo, and show that selective inhibition of N-myristoylation leads to catastrophic and irreversible failure to assemble the inner membrane complex, a critical subcellular organelle in the parasite life cycle. Our studies provide the basis for the development of new antimalarials targeting N-myristoyltransferase.

  3. MIPHENO: Data normalization for high throughput metabolic analysis.

    EPA Science Inventory

    High throughput methodologies such as microarrays, mass spectrometry and plate-based small molecule screens are increasingly used to facilitate discoveries from gene function to drug candidate identification. These large-scale experiments are typically carried out over the course...

  4. Understanding the biology of the Plasmodium falciparum apicoplast; an excellent target for antimalarial drug development.

    PubMed

    Chakraborty, Arnish

    2016-08-01

    Malaria is a life-threatening tropical disease, caused by the intracellular parasite Plasmodium falciparum. The World Health Organization counts malaria as one of the top ten causes of worldwide death. The unavailability of a successful malaria vaccine and the ever-increasing instances of drug resistance in the malaria parasite demand the discovery of new targets within P. falciparum for the development of next generation antimalarials. Fortunately, all apicomplexan parasites, including P. falciparum harbor a relict, non-photosynthetic plastid known as the apicoplast. The apicoplast is a semi-autonomous organelle within P. falciparum containing a 35kb circular genome. Despite a genome of its own, majority of the apicoplast proteins are encoded by the parasite nucleus and imported into the apicoplast. The organelle has been shown to be essential to P. falciparum survival and the loss the apicoplast manifests as a 'delayed death' response in the parasite. The apicoplast has evolved out of cyanobacteria in a complex, two step endosymbiotic event. As a result the architecture and the gene expression machinery of the apicoplast is quite bacteria-like and is susceptible to a wide range of antibiotics such as fosmidomycin, tetracycline, azithromycin, clindamycin and triclosan. The biosynthetic pathways for isoprenoids, fatty acids and heme operate within the malaria apicoplast, making the organelle an excellent target for drug development. The review focuses on the evolution, biology and the essentiality of the apicoplast within the malaria parasite and discusses some of the recent achievements towards the design and discovery of apicoplast targeted antimalarial compounds. PMID:27381078

  5. Stability of the Antimalarial Drug Dihydroartemisinin under Physiologically Relevant Conditions: Implications for Clinical Treatment and Pharmacokinetic and In Vitro Assays

    PubMed Central

    Parapini, Silvia; Olliaro, Piero; Navaratnam, Visweswaran; Taramelli, Donatella

    2015-01-01

    Artemisinins are peroxidic antimalarial drugs known to be very potent but highly chemically unstable; they degrade in the presence of ferrous iron, Fe(II)-heme, or biological reductants. Less documented is how this translates into chemical stability and antimalarial activity across a range of conditions applying to in vitro testing and clinical situations. Dihydroartemisinin (DHA) is studied here because it is an antimalarial drug on its own and the main metabolite of other artemisinins. The behaviors of DHA in phosphate-buffered saline, plasma, or erythrocyte lysate at different temperatures and pH ranges were examined. The antimalarial activity of the residual drug was evaluated using the chemosensitivity assay on Plasmodium falciparum, and the extent of decomposition of DHA was established through use of high-performance liquid chromatography with electrochemical detection analysis. The role of the Fe(II)-heme was investigated by blocking its reactivity using carbon monoxide (CO). A significant reduction in the antimalarial activity of DHA was seen after incubation in plasma and to a lesser extent in erythrocyte lysate. Activity was reduced by half after 3 h and almost completely abolished after 24 h. Serum-enriched media also affected DHA activity. Effects were temperature and pH dependent and paralleled the increased rate of decomposition of DHA from pH 7 upwards and in plasma. These results suggest that particular care should be taken in conducting and interpreting in vitro studies, prone as their results are to experimental and drug storage conditions. Disorders such as fever, hemolysis, or acidosis associated with malaria severity may contribute to artemisinin instability and reduce their clinical efficacy. PMID:25918150

  6. Mass administration of the antimalarial drug mefloquine to Guantánamo detainees: a critical analysis.

    PubMed

    Nevin, Remington L

    2012-10-01

    Recently, evidence has emerged from an unusual form of mass drug administration practised among detainees held at US Naval Station Guantánamo Bay, Cuba ('Guantánamo'), ostensibly as a public health measure. Mefloquine, an antimalarial drug originally developed by the US military, whose use is associated with a range of severe neuropsychiatric adverse effects, was administered at treatment doses to detainees immediately upon their arrival at Guantánamo, prior to laboratory testing for malaria and irrespective of symptoms of disease. In this analysis, the history of mefloquine's development is reviewed and the indications for its administration at treatment doses are discussed. The stated rationale for the use of mefloquine among Guantánamo detainees is then evaluated in the context of accepted forms of population-based malaria control. It is concluded that there was no plausible public health indication for the use of mefloquine at Guantánamo and that based on prevailing standards of care, the clinical indications for its use are decidedly unclear. This analysis suggests the troubling possibility that the use of mefloquine at Guantánamo may have been motivated in part by knowledge of the drug's adverse effects, and points to a critical need for further investigation to resolve unanswered questions regarding the drug's potentially inappropriate use. PMID:22882560

  7. Development of a Specific Monoclonal Antibody-Based ELISA to Measure the Artemether Content of Antimalarial Drugs

    PubMed Central

    He, Lishan; Zhang, Liang; Cao, Zhen; Zhang, Wei; Zhang, Rui; Tan, Guiyu; Wang, Baomin; Cui, Liwang

    2013-01-01

    Artemether is one of the artemisinin derivatives that are active ingredients in antimalarial drugs. Counterfeit and substandard antimalarial drugs have become a serious problem, which demands reliable analytical tools and implementation of strict regulation of drug quality. Structural similarity among artemisinin analogs is a challenge to develop immunoassays that are specific to artemisinin derivatives. To produce specific antibodies to artemether, we used microbial fermentation of artemether to obtain 9-hydroxyartemether, which was subsequently used to prepare a 9-O-succinylartemether hapten for conjugation with ovalbumin as the immunogen. A monoclonal antibody (mAb), designated as 2G12E1, was produced with high specificity to artemether. 2G12E1 showed low cross reactivities to dihydroartemisinin, artemisinin, artesunate and other major antimalarial drugs. An indirect competitive enzyme linked immunosorbent assay (icELISA) developed showed a concentration causing 50% of inhibition for artemether as 3.7 ng mL−1 and a working range of 0.7–19 ng mL−1. The icELISA was applied for determination of artemether content in different commercial drugs and the results were comparable to those determined by high-performance liquid chromatography analysis. In comparison with reported broad cross activity of anti-artemisinin mAbs, the most notable advantage of the 2G12E1-based ELISA is its high specificity to artemether only. PMID:24236102

  8. High throughput screening technologies for ion channels

    PubMed Central

    Yu, Hai-bo; Li, Min; Wang, Wei-ping; Wang, Xiao-liang

    2016-01-01

    Ion channels are involved in a variety of fundamental physiological processes, and their malfunction causes numerous human diseases. Therefore, ion channels represent a class of attractive drug targets and a class of important off-targets for in vitro pharmacological profiling. In the past decades, the rapid progress in developing functional assays and instrumentation has enabled high throughput screening (HTS) campaigns on an expanding list of channel types. Chronologically, HTS methods for ion channels include the ligand binding assay, flux-based assay, fluorescence-based assay, and automated electrophysiological assay. In this review we summarize the current HTS technologies for different ion channel classes and their applications. PMID:26657056

  9. Validation of ELISA for Quantitation of Artemisinin-Based Antimalarial Drugs

    PubMed Central

    Wang, Min; Cui, Yongliang; Zhou, Guofa; Yan, Guiyun; Cui, Liwang; Wang, Baomin

    2013-01-01

    The circulation of counterfeit or substandard artemisinins (ARTs) in malaria-endemic areas poses a serious threat to the long-term use of these drugs. Here, we validated an indirect competitive enzyme-linked immunosorbent assay (icELISA) for quantification of ARTs and found that 50% of inhibitory concentrations of dihydroartemisinin, artemether, and artesunate were 8.1, 207.0, and 4.7 ng/mL, respectively. We compared the icELISA with high-performance liquid chromatography (HPLC) for quantifying ART and its derivatives in 22 convenience samples of commercial antimalarial drugs. Paired t tests showed a borderline significant difference between the two methods (mean = 0.03, 95% confidence interval [CI] 0.00–0.07, P = 0.074) and the icELISA results were more variable than those of the HPLC analysis (P < 0.001), suggesting that further improvement is needed to enhance the performance of the icELISA. Our results showed that the icELISA has the potential to be improved for quality assurance of ARTs at the point of care in endemic settings. PMID:24080636

  10. High-throughput continuous cryopump

    SciTech Connect

    Foster, C.A.

    1986-01-01

    A cryopump with a unique method of regeneration which allows continuous operation at high throughput has been constructed and tested. Deuterium was pumped continuously at a throughput of 30 Torr.L/s at a speed of 2000 L/s and a compression ratio of 200. Argon was pumped at a throughput of 60 Torr.L/s at a speed of 1275 L/s. To produce continuous operation of the pump, a method of regeneration that does not thermally cycle the pump is employed. A small chamber (the ''snail'') passes over the pumping surface and removes the frost from it either by mechanical action with a scraper or by local heating. The material removed is topologically in a secondary vacuum system with low conductance into the primary vacuum; thus, the exhaust can be pumped at pressures up to an effective compression ratio determined by the ratio of the pumping speed to the leakage conductance of the snail. The pump, which is all-metal-sealed and dry and which regenerates every 60 s, would be an ideal system for pumping tritium. Potential fusion applications are for mpmp limiters, for repeating pneumatic pellet injection lines, and for the centrifuge pellet injector spin tank, all of which will require pumping tritium at high throughput. Industrial applications requiring ultraclean pumping of corrosive gases at high throughput, such as the reactive ion etch semiconductor process, may also be feasible.

  11. Differentiation from human pluripotent stem cells of cortical neurons of the superficial layers amenable to psychiatric disease modeling and high-throughput drug screening.

    PubMed

    Boissart, C; Poulet, A; Georges, P; Darville, H; Julita, E; Delorme, R; Bourgeron, T; Peschanski, M; Benchoua, A

    2013-01-01

    Cortical neurons of the superficial layers (II-IV) represent a pivotal neuronal population involved in the higher cognitive functions of the human and are particularly affected by psychiatric diseases with developmental manifestations such as schizophrenia and autism. Differentiation protocols of human pluripotent stem cells (PSC) into cortical neurons have been achieved, opening the way to in vitro modeling of neuropsychiatric diseases. However, these protocols commonly result in the asynchronous production of neurons typical for the different layers of the cortex within an extended period of culture, thus precluding the analysis of specific subtypes of neurons in a standardized manner. Addressing this issue, we have successfully captured a stable population of self-renewing late cortical progenitors (LCPs) that synchronously and massively differentiate into glutamatergic cortical neurons of the upper layers. The short time course of differentiation into neurons of these progenitors has made them amenable to high-throughput assays. This has allowed us to analyze the capability of LCPs at differentiating into post mitotic neurons as well as extending and branching neurites in response to a collection of selected bioactive molecules. LCPs and cortical neurons of the upper layers were successfully produced from patient-derived-induced PSC, indicating that this system enables functional studies of individual-specific cortical neurons ex vivo for disease modeling and therapeutic purposes. PMID:23962924

  12. Fast Gradient Elution Reversed-Phase HPLC with Diode-Array Detection as a High Throughput Screening Method for Drugs of Abuse

    SciTech Connect

    Peter W. Carr; K.M. Fuller; D.R. Stoll; L.D. Steinkraus; M.S. Pasha; Glenn G. Hardin

    2005-12-30

    A new approach has been developed by modifying a conventional gradient elution liquid chromatograph for the high throughput screening of biological samples to detect the presence of regulated intoxicants. The goal of this work was to improve the speed of a gradient elution screening method over current approaches by optimizing the operational parameters of both the column and the instrument without compromising the reproducibility of the retention times, which are the basis for the identification. Most importantly, the novel instrument configuration substantially reduces the time needed to re-equilibrate the column between gradient runs, thereby reducing the total time for each analysis. The total analysis time for each gradient elution run is only 2.8 minutes, including 0.3 minutes for column reequilibration between analyses. Retention times standard calibration solutes are reproducible to better than 0.002 minutes in consecutive runs. A corrected retention index was adopted to account for day-to-day and column-to-column variations in retention time. The discriminating power and mean list length were calculated for a library of 47 intoxicants and compared with previous work from other laboratories to evaluate fast gradient elution HPLC as a screening tool.

  13. Salinomycin and Other Ionophores as a New Class of Antimalarial Drugs with Transmission-Blocking Activity

    PubMed Central

    D'Alessandro, Sarah; Corbett, Yolanda; Ilboudo, Denise P.; Misiano, Paola; Dahiya, Nisha; Abay, Solomon M.; Habluetzel, Annette; Grande, Romualdo; Gismondo, Maria R.; Dechering, Koen J.; Koolen, Karin M. J.; Sauerwein, Robert W.; Taramelli, Donatella; Parapini, Silvia

    2015-01-01

    The drug target profile proposed by the Medicines for Malaria Venture for a malaria elimination/eradication policy focuses on molecules active on both asexual and sexual stages of Plasmodium, thus with both curative and transmission-blocking activities. The aim of the present work was to investigate whether the class of monovalent ionophores, which includes drugs used in veterinary medicine and that were recently proposed as human anticancer agents, meets these requirements. The activity of salinomycin, monensin, and nigericin on Plasmodium falciparum asexual and sexual erythrocytic stages and on the development of the Plasmodium berghei and P. falciparum mosquito stages is reported here. Gametocytogenesis of the P. falciparum strain 3D7 was induced in vitro, and gametocytes at stage II and III or stage IV and V of development were treated for different lengths of time with the ionophores and their viability measured with the parasite lactate dehydrogenase (pLDH) assay. The monovalent ionophores efficiently killed both asexual parasites and gametocytes with a nanomolar 50% inhibitory concentration (IC50). Salinomycin showed a fast speed of kill compared to that of standard drugs, and the potency was higher on stage IV and V than on stage II and III gametocytes. The ionophores inhibited ookinete development and subsequent oocyst formation in the mosquito midgut, confirming their transmission-blocking activity. Potential toxicity due to hemolysis was excluded, since only infected and not normal erythrocytes were damaged by ionophores. Our data strongly support the downstream exploration of monovalent ionophores for repositioning as new antimalarial and transmission-blocking leads. PMID:26055362

  14. Anti-malarial drug quality in Lagos and Accra - a comparison of various quality assessments

    PubMed Central

    2010-01-01

    Background Two major cities in West Africa, Accra, the capital of Ghana, and Lagos, the largest city of Nigeria, have significant problems with substandard pharmaceuticals. Both have actively combated the problem in recent years, particularly by screening products on the market using the Global Pharma Health Fund e.V. Minilab® protocol. Random sampling of medicines from the two cities at least twice over the past 30 months allows a tentative assessment of whether improvements in drug quality have occurred. Since intelligence provided by investigators indicates that some counterfeit producers may be adapting products to pass Minilab tests, the results are compared with those from a Raman spectrometer and discrepancies are discussed. Methods Between mid-2007 and early-2010, samples of anti-malarial drugs were bought covertly from pharmacies in Lagos on three different occasions (October 2007, December 2008, February 2010), and from pharmacies in Accra on two different occasions (October 2007, February 2010). All samples were tested using the Minilab® protocol, which includes disintegration and active ingredient assays as well as visual inspection, and most samples were also tested by Raman spectrometry. Results In Lagos, the failure rate in the 2010 sampling fell to 29% of the 2007 finding using the Minilab® protocol, 53% using Raman spectrometry, and 46% using visual inspection. In Accra, the failure rate in the 2010 sampling fell to 54% of the 2007 finding using the Minilab® protocol, 72% using Raman spectrometry, and 90% using visual inspection. Conclusions The evidence presented shows that drug quality is probably improving in both cities, especially Lagos, since major reductions of failure rates over time occur with all means of assessment. Many more samples failed when examined by Raman spectrometry than by Minilab® protocol. The discrepancy is most likely caused by the two techniques measuring different aspects of the medication and hence the discrepancy

  15. CHALLENGES IN SECONDARY ANALYSIS OF HIGH THROUGHPUT SCREENING DATA

    PubMed Central

    BLUCHER, AURORA S.; MCWEENEY, SHANNON K.

    2014-01-01

    Repurposing an existing drug for an alternative use is not only a cost effective method of development, but also a faster process due to the drug's previous clinical testing and established pharmokinetic profiles. A potentially rich resource for computational drug repositioning approaches is publically available high throughput screening data, available in databases such as PubChem Bioassay and ChemBank. We examine statistical and computational considerations for secondary analysis of publicly available high throughput screening (HTS) data with respect to metadata, data quality, and completeness. We discuss developing methods and best practices that can help to ameliorate these issues. PMID:24297539

  16. Hemin potentiates the anti-hepatitis C virus activity of the antimalarial drug artemisinin

    SciTech Connect

    Paeshuyse, Jan; Coelmont, Lotte; Vliegen, Inge; Hemel, Johan van; Vandenkerckhove, Jan; Peys, Eric; Sas, Benedikt; Clercq, Erik De; Neyts, Johan . E-mail: johan.neyts@rega.kuleuven.be

    2006-09-15

    We report that the antimalarial drug artemisinin inhibits hepatitis C virus (HCV) replicon replication in a dose-dependent manner in two replicon constructs at concentrations that have no effect on the proliferation of the exponentially growing host cells. The 50% effective concentration (EC{sub 5}) for inhibition of HCV subgenomic replicon replication in Huh 5-2 cells (luciferase assay) by artemisinin was 78 {+-} 21 {mu}M. Hemin, an iron donor, was recently reported to inhibit HCV replicon replication [mediated by inhibition of the viral polymerase (C. Fillebeen, A.M. Rivas-Estilla, M. Bisaillon, P. Ponka, M. Muckenthaler, M.W. Hentze, A.E. Koromilas, K. Pantopoulos, Iron inactivates the RNA polymerase NS5B and suppresses subgenomic replication of hepatitis C virus, J. Biol. Chem. 280 (2005) 9049-9057.)] at a concentration that had no adverse effect on the host cells. When combined, artemisinin and hemin resulted, over a broad concentration range, in a pronounced synergistic antiviral activity. Also at a concentration (2 {mu}M) that alone had no effect on HCV replication, hemin still potentiated the anti-HCV activity of artemisinin.

  17. Molecular markers of anti-malarial drug resistance in Lahj Governorate, Yemen: baseline data and implications

    PubMed Central

    2011-01-01

    Background This is an investigation of anti-malarial molecular markers coupled with a therapeutic efficacy test of chloroquine (CQ) against falciparum malaria in an area of unstable malaria in Lahj Governorate, Yemen. The study was aimed at assessment of therapeutic response to CQ and elucidation of baseline information on molecular markers for Plasmodium falciparum resistance against CQ and sulphadoxine/pyrimethamine (SP). Methods Between 2002 and 2003 the field test was conducted according to the standard WHO protocol to evaluate the therapeutic efficacy of CQ in 124 patients with falciparum malaria in an endemic area in Lahj Governorate in Yemen. Blood samples collected during this study were analysed for P. falciparum chloroquine resistance transporter gene (pfcrt)-76 polymorphisms, mutation pfcrt-S163R and the antifolate resistance-associated mutations dihydrofolate reductase (dhfr)-C59R and dihydropteroate synthase (dhps)-K540E. Direct DNA sequencing of the pfcrt gene from three representative field samples was carried out after DNA amplification of the 13 exons of the pfcrt gene. Results Treatment failure was detected in 61% of the 122 cases that completed the 14-day follow-up. The prevalence of mutant pfcrt T76 was 98% in 112 amplified pre-treatment samples. The presence of pfcrt T76 was poorly predictive of in vivo CQ resistance (PPV = 61.8%, 95% CI = 52.7-70.9). The prevalence of dhfr Arg-59 mutation in 99 amplified samples was 5%, while the dhps Glu-540 was not detected in any of 119 amplified samples. Sequencing the pfcrt gene confirmed that Yemeni CQ resistant P. falciparum carry the old world (Asian and African) CQ resistant haplotype CVIETSESI at positions 72,73,74,75,76,220,271, 326 and 371. Conclusion This is the first study to report baseline information on the characteristics and implications of anti-malarial drug resistance markers in Yemen. It is also the first report of the haplotype associated with CQR P. falciparum parasites from Yemen

  18. High throughput protein production screening

    DOEpatents

    Beernink, Peter T.; Coleman, Matthew A.; Segelke, Brent W.

    2009-09-08

    Methods, compositions, and kits for the cell-free production and analysis of proteins are provided. The invention allows for the production of proteins from prokaryotic sequences or eukaryotic sequences, including human cDNAs using PCR and IVT methods and detecting the proteins through fluorescence or immunoblot techniques. This invention can be used to identify optimized PCR and WT conditions, codon usages and mutations. The methods are readily automated and can be used for high throughput analysis of protein expression levels, interactions, and functional states.

  19. High-Throughput Sequencing Technologies

    PubMed Central

    Reuter, Jason A.; Spacek, Damek; Snyder, Michael P.

    2015-01-01

    Summary The human genome sequence has profoundly altered our understanding of biology, human diversity and disease. The path from the first draft sequence to our nascent era of personal genomes and genomic medicine has been made possible only because of the extraordinary advancements in DNA sequencing technologies over the past ten years. Here, we discuss commonly used high-throughput sequencing platforms, the growing array of sequencing assays developed around them as well as the challenges facing current sequencing platforms and their clinical application. PMID:26000844

  20. Rational Design of Antimalarial Drugs Using Molecular Modeling and Statistical Analysis.

    PubMed

    Santos, Cleydson Breno Rodrigues dos; Lobato, Cleison Carvalho; Braga, Francinaldo Sarges; Costa, Josivan da Silva; Favacho, Hugo Alexandre Silva; Carvalho, Jose Carlos Tavares; Macedo, Williams Jorge da Cruz; Brasil, Davi Do Socorro Barros; Silva, Carlos Henrique Tomich de Paula da; Silva Hage-Melim, Lorane Izabel da

    2015-01-01

    Artemisinin is an antimalarial compound isolated from Artemisia annua L. that is effective against Plasmodium falciparum. This paper proposes the development of new antimalarial derivatives of artemisinin from a SAR study and statistical analysis by multiple linear regression (MLR). The HF/6-31G** method was used to determine the molecular properties of artemisinin and 10 derivatives with antimalarial action. MEP maps and molecular docking were used to study the interface between ligand and receptor (heme). The Pearson correlation was used to choose the most important properties interrelated to the antimalarial activity: Hydration Energy (HE), Energy of the Complex (Ecplex), bond length (FeO1), and maximum index of R/Electronegativity of Sanderson (RTe+). After the Pearson correlation, 72 MLR models were built between antimalarial activity and molecular properties; the statistical quality of the models was evaluated by means of correlation coefficient (r), squared correlation coefficient (r(2)), explained variance (adjusted R(2)), standard error of estimate (SEE), and variance ratio (F), and only four models showed predictive ability. The selected models were used to predict the antimalarial activity of ten new artemisinin derivatives (test set) with unknown activity, and only eight of these compounds were predicted to be more potent than artemisinin, and were therefore subjected to theoretical studies of pharmacokinetic and toxicological properties. The test set showed satisfactory results for six new artemisinin compounds which is a promising factor for future synthesis and biological assays. PMID:26017698

  1. Cyclosporin A in Membrane Lipids Environment: Implications for Antimalarial Activity of the Drug--The Langmuir Monolayer Studies.

    PubMed

    Dynarowicz-Łątka, Patrycja; Wnętrzak, Anita; Makyła-Juzak, Katarzyna

    2015-12-01

    Cyclosporin A (CsA), a hydrophobic cyclic peptide produced by the fungus Tolypocladium inflatum, is well known for its high efficiency as an immunosuppressor for transplanted organs and anti-inflammatory properties; however, it is also active as antiparasitic (antimalarial) drug. Antimalarial mechanism of CsA action lacks a detailed understanding at molecular level. Due to a high lipophilicity of CsA, it is able to interact with lipids of cellular membrane; however, molecular targets of this drug are still unknown. To get a deeper insight into the mode of antimalarial activity of CsA, it is of utmost importance to examine its interactions with membrane components. To reach this goal, the Langmuir monolayer technique, which serves as a very useful, easy to handle and controllable model of biomembranes, has been employed. In this work, the interactions between CsA and main membrane lipids, i.e., cholesterol (Chol), 2-oleoyl-1-palmitoyl-3-phosphocholine (POPC), and sphingomyelin (SM), have been investigated. Attractive interactions are observed only for CsA mixtures with SM, while repulsive forces occur in systems containing remaining membrane lipids. Taking into consideration mutual interactions between membrane lipids (Chol-SM; Chol-POPC and SM-POPC), the behavior of CsA in model erythrocyte membrane of normal and infected cells has been analyzed. Our results prove strong affinity of CsA to SM in membrane environment. Since normal and parasitized erythrocytes differ significantly in the level of SM, this phospholipid may be considered as a molecular target for antimalarial activity of CsA.

  2. Pharmacoeconomics of Antimalarials in Private-for-Profit (PFP) Drug-Outlets in Gulu and Kitgum Towns, Northern Uganda

    PubMed Central

    Maghanga, Mshilla; Gerald, Obai; David, Musoke

    2015-01-01

    Background Clinically-diagnosed malaria is the leading cause of morbidity and mortality in Uganda accounting for 25 to 40% of outpatients, 15 to 20% of all hospital admissions, and 9 to 14% of all hospital deaths. This situation was exacerbated by The Lord’s Resistance Army (LRA) rebellion in northern Uganda which completely ran down the health care system. While malaria remains the number one killer disease in northern Uganda, antimalarials are lacking in the public health facilities. Consequently, Private-for-profit drug-outlets have come up to help bridge the gap. However, the cost-effectiveness and treatment outcome ratings of antimalarials are not clear. Objective: To assess the pharmacoeconomics of malaria treatment in Private-for-profit (PFP) drug-outlets in Gulu Municipality and Kitgum Town Council. Methodology This was a descriptive cross-sectional study sites were registered drug outlets. Study participants were drug-outlet owners, their employees, and malaria patients. We employed both purposive and random sampling methods to select the study participants. Data were collected using questionnaires and analysed using the SPSS computer package. Results Up to 91.1% of the respondents indicated that antimalarials are expensive. The prices varied from less than 5,000 to over 20,000 Ugandan shillings per dose (Exchange rate: 1$ = Ush 2,650). Fansidar and chloroquine were rated as being relatively cheap and ACTs expensive (Ush 11,000 to 15,000). Duration of treatment, frequency of administration, needles and syringes, raised the cost of some medicines. Most patients preferred cheap medicines (76.2%); those with low administration frequencies (77.5%); and those with short treatment duration (95%). Most patients (80.9%) buy antimalarials without testing, while 66.6% do not buy full doses. Conclusion The cost benefit analysis of the use of antimalarials is unfavourable. The unit price of the medicines, their irrational use and the lack of professionals in the

  3. High-throughput screening for modulators of cellular contractile force†

    PubMed Central

    Park, Chan Young; Zhou, Enhua H.; Tambe, Dhananjay; Chen, Bohao; Lavoie, Tera; Dowell, Maria; Simeonov, Anton; Maloney, David J.; Marinkovic, Aleksandar; Tschumperlin, Daniel J.; Burger, Stephanie; Frykenberg, Matthew; Butler, James P.; Stamer, W. Daniel; Johnson, Mark; Solway, Julian; Fredberg, Jeffrey J.

    2015-01-01

    When cellular contractile forces are central to pathophysiology, these forces comprise a logical target of therapy. Nevertheless, existing high-throughput screens are limited to upstream signalling intermediates with poorly defined relationships to such a physiological endpoint. Using cellular force as the target, here we report a new screening technology and demonstrate its applications using human airway smooth muscle cells in the context of asthma and Schlemm's canal endothelial cells in the context of glaucoma. This approach identified several drug candidates for both asthma and glaucoma. We attained rates of 1000 compounds per screening day, thus establishing a force-based cellular platform for high-throughput drug discovery. PMID:25953078

  4. The synergy between combinatorial chemistry and high-throughput screening.

    PubMed

    Diller, David J

    2008-05-01

    Despite the initial promise of combinatorial chemistry, particularly large library combinatorial chemistry, to greatly accelerate drug discovery, this approach has not been fully utilized as a means to build the compound collections of pharmaceutical and biotechnology companies. This review highlights some of the strengths of large library combinatorial chemistry as a means of generating molecules for lead discovery, such as providing rich and robust structure-activity relationships around each hit series. The challenges and concepts emerging from traditional high-throughput screening and fragment-based drug design, how these methods influence the design of large combinatorial libraries and the interpretation of the ensuing high-throughput screening data are also highlighted.

  5. Surveillance of Travellers: An Additional Tool for Tracking Antimalarial Drug Resistance in Endemic Countries

    PubMed Central

    Gharbi, Myriam; Flegg, Jennifer A.; Pradines, Bruno; Berenger, Ako; Ndiaye, Magatte; Djimdé, Abdoulaye A.; Roper, Cally; Hubert, Véronique; Kendjo, Eric; Venkatesan, Meera; Brasseur, Philippe; Gaye, Oumar; Offianan, André T.; Penali, Louis; Le Bras, Jacques; Guérin, Philippe J.; Study, Members of the French National Reference Center for Imported Malaria

    2013-01-01

    Introduction There are growing concerns about the emergence of resistance to artemisinin-based combination therapies (ACTs). Since the widespread adoption of ACTs, there has been a decrease in the systematic surveillance of antimalarial drug resistance in many malaria-endemic countries. The aim of this work was to test whether data on travellers returning from Africa with malaria could serve as an additional surveillance system of local information sources for the emergence of drug resistance in endemic-countries. Methodology Data were collected from travellers with symptomatic Plasmodium falciparum malaria returning from Senegal (n = 1,993), Mali (n = 2,372), Cote d’Ivoire (n = 4,778) or Cameroon (n = 3,272) and recorded in the French Malaria Reference Centre during the period 1996–2011. Temporal trends of the proportion of parasite isolates that carried the mutant genotype, pfcrt 76T, a marker of resistance to chloroquine (CQ) and pfdhfr 108N, a marker of resistance to pyrimethamine, were compared for travellers and within-country surveys that were identified through a literature review in PubMed. The in vitro response to CQ was also compared between these two groups for parasites from Senegal. Results The trends in the proportion of parasites that carried pfcrt 76T, and pfdhfr 108N, were compared for parasites from travellers and patients within-country using the slopes of the curves over time; no significant differences in the trends were found for any of the 4 countries. These results were supported by in vitro analysis of parasites from the field in Senegal and travellers returning to France, where the trends were also not significantly different. Conclusion The results have not shown different trends in resistance between parasites derived from travellers or from parasites within-country. This work highlights the value of an international database of drug responses in travellers as an additional tool to assess the emergence of drug

  6. Incorporating Stage-Specific Drug Action into Pharmacological Modeling of Antimalarial Drug Treatment

    PubMed Central

    2016-01-01

    Pharmacological modeling of antiparasitic treatment based on a drug's pharmacokinetic and pharmacodynamic properties plays an increasingly important role in identifying optimal drug dosing regimens and predicting their potential impact on control and elimination programs. Conventional modeling of treatment relies on methods that do not distinguish between parasites at different developmental stages. This is problematic for malaria parasites, as their sensitivity to drugs varies substantially during their 48-h developmental cycle. We investigated four drug types (short or long half-lives with or without stage-specific killing) to quantify the accuracy of the standard methodology. The treatment dynamics of three drug types were well characterized with standard modeling. The exception were short-half-life drugs with stage-specific killing (i.e., artemisinins) because, depending on time of treatment, parasites might be in highly drug-sensitive stages or in much less sensitive stages. We describe how to bring such drugs into pharmacological modeling by including additional variation into the drug's maximal killing rate. Finally, we show that artemisinin kill rates may have been substantially overestimated in previous modeling studies because (i) the parasite reduction ratio (PRR) (generally estimated to be 104) is based on observed changes in circulating parasite numbers, which generally overestimate the “true” PRR, which should include both circulating and sequestered parasites, and (ii) the third dose of artemisinin at 48 h targets exactly those stages initially hit at time zero, so it is incorrect to extrapolate the PRR measured over 48 h to predict the impact of doses at 48 h and later. PMID:26902760

  7. The antimalarial drug primaquine targets Fe-S cluster proteins and yeast respiratory growth.

    PubMed

    Lalève, Anaïs; Vallières, Cindy; Golinelli-Cohen, Marie-Pierre; Bouton, Cécile; Song, Zehua; Pawlik, Grzegorz; Tindall, Sarah M; Avery, Simon V; Clain, Jérôme; Meunier, Brigitte

    2016-04-01

    Malaria is a major health burden in tropical and subtropical countries. The antimalarial drug primaquine is extremely useful for killing the transmissible gametocyte forms of Plasmodium falciparum and the hepatic quiescent forms of P. vivax. Yet its mechanism of action is still poorly understood. In this study, we used the yeast Saccharomyces cerevisiae model to help uncover the mode of action of primaquine. We found that the growth inhibitory effect of primaquine was restricted to cells that relied on respiratory function to proliferate and that deletion of SOD2 encoding the mitochondrial superoxide dismutase severely increased its effect, which can be countered by the overexpression of AIM32 and MCR1 encoding mitochondrial enzymes involved in the response to oxidative stress. This indicated that ROS produced by respiratory activity had a key role in primaquine-induced growth defect. We observed that Δsod2 cells treated with primaquine displayed a severely decreased activity of aconitase that contains a Fe-S cluster notoriously sensitive to oxidative damage. We also showed that in vitro exposure to primaquine impaired the activity of purified aconitase and accelerated the turnover of the Fe-S cluster of the essential protein Rli1. It is suggested that ROS-labile Fe-S groups are the primary targets of primaquine. Aconitase activity is known to be essential at certain life-cycle stages of the malaria parasite. Thus primaquine-induced damage of its labile Fe-S cluster - and of other ROS-sensitive enzymes - could inhibit parasite development. PMID:26629948

  8. Low-cost, high-speed identification of counterfeit antimalarial drugs on paper.

    PubMed

    Koesdjojo, Myra T; Wu, Yuanyuan; Boonloed, Anukul; Dunfield, Elizabeth M; Remcho, Vincent T

    2014-12-01

    With the emergence of artesunate antimalarial counterfeiting in Southeast Asia and sub-Saharan Africa, we present the production of a rapid, inexpensive and simple colorimetric-based testing kit for the detection of counterfeit artesunate in order to preserve life and prevent the development of multi-drug resistant malaria. The kit works based on paper microfluidics which offer several advantages over conventional microfluidics, and has great potential to generate inexpensive, easy-to-use, rapid and disposable diagnostic devices. Here, we have developed a colorimetric assay that is specific to artesunate and turns yellow upon addition of the sample. The test can be done within minutes, and allows for a semi-quantitative analysis of the artesunate tablets by comparing the developed yellow color on the paper test to a color-coded key chart that comes with the kit. A more accurate and precise analysis is done by utilizing a color analyzer on an iPhone camera that measures the color intensity of the developed color on the paper chip. A digital image of the chip was taken and analyzed by measuring the average gray intensity of the color developed on the paper circle. A plot of the artesunate concentration versus the average gray scale intensity was generated. Results show that the intensity of the yellow color developed on the paper test was consistent and proportional to the amount of artesunate present in the sample. With artesunate concentrations ranging from 0.0 to 20mg/mL, a linear calibration plot was obtained with a detection limit of 0.98 mg/mL.

  9. Antidiabetic and antimalarial biguanide drugs are metal-interactive antiproteolytic agents.

    PubMed

    Sweeney, Deacon; Raymer, Michael L; Lockwood, Thomas D

    2003-08-15

    Various biguanide derivatives are used as antihyperglycemic and antimalarial drugs (e.g., 1,1-dimethyl biguanide (metformin), phenylethyl biguanide (phenformin), N-(4-chlorophenyl)-N'-(isopropyl)-imidodicarbonimidic diamide (proguanil)); however, no common mechanism has been suggested in these controversial therapeutic actions. Biguanides bind endogenous metals that inhibit cysteine proteases independently, e.g., Zn(2+), Cu(2+), Fe(3+). Here, various biguanide derivatives are reported to be metal-interactive inhibitors of cathepsin B from mammals and falcipain-2 from Plasmodium falciparum. Structural homologies were identified among the Phe-Arg protease substrate motif and the metal complexes of phenformin and proguanil. Molecular modeling revealed that the position of the scissile amide substrate bond corresponds to the biguanide-complexed inhibitory metal when the phenyl groups are homologously aligned. Binding of the phenformin-metal complex within the active site of human cathepsin B was modeled with computational docking. A major binding mode involved binding of the drug phenyl group at the protease S2 subsite, and the complexed inhibitory metal shared between the drug and the protease Cys29-His199 catalytic pair. Cysteine protease inhibition was assayed with carbobenzyloxy-PHE-ARG-7-aminomethylcoumarin substrate. In the absence of metal ions, phenformin was a weakly competitive protease inhibitor (apparent K(i) several microM); however, metformin was noninhibitory. In contrast, the metal complexes of both metformin and phenformin were protease inhibitors with potency at therapeutic concentrations. Biguanide-metal complexes were more potent cysteine protease inhibitors than either the biguanide or metal ions alone, i.e., synergistic. Similar to chloroquine, therapeutic extracellular concentrations of metformin, phenformin, and proguanil caused metal-interactive inhibition of lysosomal protein degradation as bioassayed in primary tissue using perfused

  10. Quinine, an old anti-malarial drug in a modern world: role in the treatment of malaria

    PubMed Central

    2011-01-01

    Quinine remains an important anti-malarial drug almost 400 years after its effectiveness was first documented. However, its continued use is challenged by its poor tolerability, poor compliance with complex dosing regimens, and the availability of more efficacious anti-malarial drugs. This article reviews the historical role of quinine, considers its current usage and provides insight into its appropriate future use in the treatment of malaria. In light of recent research findings intravenous artesunate should be the first-line drug for severe malaria, with quinine as an alternative. The role of rectal quinine as pre-referral treatment for severe malaria has not been fully explored, but it remains a promising intervention. In pregnancy, quinine continues to play a critical role in the management of malaria, especially in the first trimester, and it will remain a mainstay of treatment until safer alternatives become available. For uncomplicated malaria, artemisinin-based combination therapy (ACT) offers a better option than quinine though the difficulty of maintaining a steady supply of ACT in resource-limited settings renders the rapid withdrawal of quinine for uncomplicated malaria cases risky. The best approach would be to identify solutions to ACT stock-outs, maintain quinine in case of ACT stock-outs, and evaluate strategies for improving quinine treatment outcomes by combining it with antibiotics. In HIV and TB infected populations, concerns about potential interactions between quinine and antiretroviral and anti-tuberculosis drugs exist, and these will need further research and pharmacovigilance. PMID:21609473

  11. Quality of anti-malarial drugs provided by public and private healthcare providers in south-east Nigeria

    PubMed Central

    Onwujekwe, Obinna; Kaur, Harparkash; Dike, Nkem; Shu, Elvis; Uzochukwu, Benjamin; Hanson, Kara; Okoye, Viola; Okonkwo, Paul

    2009-01-01

    Background There is little existing knowledge about actual quality of drugs provided by different providers in Nigeria and in many sub-Saharan African countries. Such information is important for improving malaria treatment that will help in the development and implementation of actions designed to improve the quality of treatment. The objective of the study was to determine the quality of drugs used for the treatment of malaria in a broad spectrum of public and private healthcare providers. Methods The study was undertaken in six towns (three urban and three rural) in Anambra state, south-east Nigeria. Anti-malarials (225 samples), which included artesunate, dihydroartemisinin, sulphadoxine-pyrimethamine (SP), quinine, and chloroquine, were either purchased or collected from randomly selected providers. The quality of these drugs was assessed by laboratory analysis of the dissolution profile using published pharmacopoeial monograms and measuring the amount of active ingredient using high performance liquid chromatography (HPLC). Findings It was found that 60 (37%) of the anti-malarials tested did not meet the United States Pharmacopoeia (USP) specifications for the amount of active ingredients, with the suspect drugs either lacking the active ingredients or containing suboptimal quantities of the active ingredients. Quinine (46%) and SP formulations (39%) were among drugs that did not satisfy the tolerance limits published in USP monograms. A total of 78% of the suspect drugs were from private facilities, mostly low-level providers, such as patent medicine dealers (vendors). Conclusion This study found that there was a high prevalence of poor quality drugs. The findings provide areas for public intervention to improve the quality of malaria treatment services. There should be enforced checks and regulation of drug supply management as well as stiffer penalties for people stocking substandard and counterfeit drugs. PMID:19208221

  12. High throughput assays for analyzing transcription factors.

    PubMed

    Li, Xianqiang; Jiang, Xin; Yaoi, Takuro

    2006-06-01

    Transcription factors are a group of proteins that modulate the expression of genes involved in many biological processes, such as cell growth and differentiation. Alterations in transcription factor function are associated with many human diseases, and therefore these proteins are attractive potential drug targets. A key issue in the development of such therapeutics is the generation of effective tools that can be used for high throughput discovery of the critical transcription factors involved in human diseases, and the measurement of their activities in a variety of disease or compound-treated samples. Here, a number of innovative arrays and 96-well format assays for profiling and measuring the activities of transcription factors will be discussed. PMID:16834538

  13. Novel anti-Cryptosporidium activity of known drugs identified by high-throughput screening against parasite fatty acyl-CoA binding protein (ACBP)

    PubMed Central

    Fritzler, Jason M.; Zhu, Guan

    2012-01-01

    Background Cryptosporidium parvum causes an opportunistic infection in AIDS patients, and no effective treatments are yet available. This parasite possesses a single fatty acyl-CoA binding protein (CpACBP1) that is localized to the unique parasitophorous vacuole membrane (PVM). The major goal of this study was to identify inhibitors from known drugs against CpACBP1 as potential new anti-Cryptosporidium agents. Methods A fluorescence assay was developed to detect CpACBP1 activity and to identify inhibitors by screening known drugs. Efficacies of top CpACBP1 inhibitors against Cryptosporidium growth in vitro were evaluated using a quantitative RT–PCR assay. Results Nitrobenzoxadiazole-labelled palmitoyl-CoA significantly increased the fluorescent emission upon binding to CpACBP1 (excitation/emission 460/538 nm), which was quantified to determine the CpACBP1 activity and binding kinetics. The fluorescence assay was used to screen a collection of 1040 compounds containing mostly known drugs, and identified the 28 most active compounds that could inhibit CpACBP1 activity with sub-micromolar IC50 values. Among them, four compounds displayed efficacies against parasite growth in vitro with low micromolar IC50 values. The effective compounds were broxyquinoline (IC50 64.9 μM), cloxyquin (IC50 25.1 μM), cloxacillin sodium (IC50 36.2 μM) and sodium dehydrocholate (IC50 53.2 μM). Conclusions The fluorescence ACBP assay can be effectively used to screen known drugs or other compound libraries. Novel anti-Cryptosporidium activity was observed in four top CpACBP1 inhibitors, which may be further investigated for their potential to be repurposed to treat cryptosporidiosis and to serve as leads for drug development. PMID:22167242

  14. An amphiphilic graft copolymer-based nanoparticle platform for reduction-responsive anticancer and antimalarial drug delivery

    NASA Astrophysics Data System (ADS)

    Najer, Adrian; Wu, Dalin; Nussbaumer, Martin G.; Schwertz, Geoffrey; Schwab, Anatol; Witschel, Matthias C.; Schäfer, Anja; Diederich, François; Rottmann, Matthias; Palivan, Cornelia G.; Beck, Hans-Peter; Meier, Wolfgang

    2016-08-01

    Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL-1. Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (+/-)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block.Medical applications of anticancer and antimalarial drugs often suffer from low aqueous

  15. Treatment of Plasmodium chabaudi Parasites with Curcumin in Combination with Antimalarial Drugs: Drug Interactions and Implications on the Ubiquitin/Proteasome System

    PubMed Central

    Neto, Zoraima; Machado, Marta; Lindeza, Ana; do Rosário, Virgílio; Gazarini, Marcos L.; Lopes, Dinora

    2013-01-01

    Antimalarial drug resistance remains a major obstacle in malaria control. Evidence from Southeast Asia shows that resistance to artemisinin combination therapy (ACT) is inevitable. Ethnopharmacological studies have confirmed the efficacy of curcumin against Plasmodium spp. Drug interaction assays between curcumin/piperine/chloroquine and curcumin/piperine/artemisinin combinations and the potential of drug treatment to interfere with the ubiquitin proteasome system (UPS) were analyzed. In vivo efficacy of curcumin was studied in BALB/c mice infected with Plasmodium chabaudi clones resistant to chloroquine and artemisinin, and drug interactions were analyzed by isobolograms. Subtherapeutic doses of curcumin, chloroquine, and artemisinin were administered to mice, and mRNA was collected following treatment for RT-PCR analysis of genes encoding deubiquitylating enzymes (DUBs). Curcumin was found be nontoxic in BALB/c mice. The combination of curcumin/chloroquine/piperine reduced parasitemia to 37% seven days after treatment versus the control group's 65%, and an additive interaction was revealed. Curcumin/piperine/artemisinin combination did not show a favorable drug interaction in this murine model of malaria. Treatment of mice with subtherapeutic doses of the drugs resulted in a transient increase in genes encoding DUBs indicating UPS interference. If curcumin is to join the arsenal of available antimalarial drugs, future studies exploring suitable drug partners would be of interest. PMID:23691276

  16. An amphiphilic graft copolymer-based nanoparticle platform for reduction-responsive anticancer and antimalarial drug delivery.

    PubMed

    Najer, Adrian; Wu, Dalin; Nussbaumer, Martin G; Schwertz, Geoffrey; Schwab, Anatol; Witschel, Matthias C; Schäfer, Anja; Diederich, François; Rottmann, Matthias; Palivan, Cornelia G; Beck, Hans-Peter; Meier, Wolfgang

    2016-08-21

    Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL(-1). Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (±)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block. PMID:27452350

  17. High-throughput screening of pesticide and veterinary drug residues in baby food by liquid chromatography coupled to quadrupole Orbitrap mass spectrometry.

    PubMed

    Jia, Wei; Chu, Xiaogang; Ling, Yun; Huang, Junrong; Chang, James

    2014-06-20

    A new analytical method was developed and validated for simultaneous analysis of 333 pesticide and veterinary drug residues in baby food. Response surface methodology was employed to optimize a generic extraction method. Ultrahigh-performance liquid chromatography and electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-ESI Q-Orbitrap) was used for the separation and detection of all the analytes. The method was validated by taking into consideration the guidelines specified in Commission Decision 2002/657/EC and SANCO/12571/2013. The extraction recoveries were in a range of 79.8-110.7%, with coefficient of variation <8.3%. The 333 compounds behave dynamic in the range 0.1-1000μgkg(-1) concentration, with correlation coefficient >0.99. The limits of detection for the analytes are in the range 0.01-5.35μgkg(-1). The limits of quantification for the analytes are in the range 0.01-9.27μgkg(-1). This method has been successfully applied on screening of pesticide and veterinary drugs in ninety-three commercial baby food samples, and tilmicosin, fenbendazole, tylosin tartrate and thiabendazole were detected in some samples tested in this study. The present study is very useful for fast screening of different food contaminants.

  18. Falsified antimalarials: a minireview.

    PubMed

    Chaccour, Carlos; Kaur, Harparkash; Del Pozo, Jose Luis

    2015-04-01

    Malaria is a curable disease, provided timely access to efficacious drugs is sought. Poor quality and, in particular, falsified antimalarial drugs harm the population of malaria endemic areas; they put lives in peril, cause economic losses to patients, families, industry, and generally undermine the trust in health systems. The extent of the problem is not easily assessed, and although a prevalence of up to 35% of poor-quality antimalarials has been reported, this number should be interpreted with caution given the heterogeneity of methods used to measure it. The trade in falsified antimalarials can be curtailed by putting in place drug quality surveillance, better legislation and improving the access and affordability of these essential drugs. PMID:25683870

  19. Imaging-Based High-Throughput Screening Assay To Identify New Molecules with Transmission-Blocking Potential against Plasmodium falciparum Female Gamete Formation

    PubMed Central

    Miguel-Blanco, Celia; Lelièvre, Joël; Delves, Michael J.; Bardera, Ana I.; Presa, Jesús L.; López-Barragán, María José; Ruecker, Andrea; Marques, Sara; Sinden, Robert E.

    2015-01-01

    In response to a call for the global eradication of malaria, drug discovery has recently been extended to identify compounds that prevent the onward transmission of the parasite, which is mediated by Plasmodium falciparum stage V gametocytes. Lately, metabolic activity has been used in vitro as a surrogate for gametocyte viability; however, as gametocytes remain relatively quiescent at this stage, their ability to undergo onward development (gamete formation) may be a better measure of their functional viability. During gamete formation, female gametocytes undergo profound morphological changes and express translationally repressed mRNA. By assessing female gamete cell surface expression of one such repressed protein, Pfs25, as the readout for female gametocyte functional viability, we developed an imaging-based high-throughput screening (HTS) assay to identify transmission-blocking compounds. This assay, designated the P. falciparum female gametocyte activation assay (FGAA), was scaled up to a high-throughput format (Z′ factor, 0.7 ± 0.1) and subsequently validated using a selection of 50 known antimalarials from diverse chemical families. Only a few of these agents showed submicromolar 50% inhibitory concentrations in the assay: thiostrepton, methylene blue, and some endoperoxides. To determine the best conditions for HTS, a robustness test was performed with a selection of the GlaxoSmithKline Tres Cantos Antimalarial Set (TCAMS) and the final screening conditions for this library were determined to be a 2 μM concentration and 48 h of incubation with gametocytes. The P. falciparum FGAA has been proven to be a robust HTS assay faithful to Plasmodium transmission-stage cell biology, and it is an innovative useful tool for antimalarial drug discovery which aims to identify new molecules with transmission-blocking potential. PMID:25801574

  20. Fast Gradient Elution Reversed-Phase Liquid Chromatography with Diode-Array Detection as a High-throughput Screening Method for Drugs of Abuse II. Data Analysis

    PubMed Central

    Porter, Sarah E. G.; Stoll, Dwight R.; Paek, Changyub; Rutan, Sarah C.; Carr, Peter W.

    2009-01-01

    In Part I of this work, we developed a method for the detection of drugs of abuse in biological samples based on fast gradient elution liquid-chromatography coupled with diode array spectroscopic detection (LC-DAD). In this part of the work, we apply the chemometric method of target factor analysis (TFA) to the chromatograms. This algorithm identifies the target compounds present in chromatograms based on a spectral library, resolves nearly co-eluting components, and differentiates between drugs with similar spectra. The ability to resolve highly overlapped peaks using the spectral data afforded by the DAD is what distinguishes the present method from conventional library searching methods. Our library has a mean list length of 1.255 and a discriminating power of 0.997 when both retention index and spectral factors are considered. The algorithm compares a library of 47 different compounds of toxicological relevance to unknown samples and identifies which compounds are present based on spectral and retention index matching. The application of a corrected retention index for identification rather than raw retention times compensates for long-term and column-to-column retention time shifts and allows for the use of a single library of spectral and retention data. Training data sets were used to establish the search and identification parameters of the method. A validation data set of 70 chromatograms was used to calculate the sensitivity (correct identification of positives) and specificity (correct identification of negatives) of the method, which were found to be 92 % and 94% respectively. PMID:17070534

  1. High-Throughput Methods for Electron Crystallography

    PubMed Central

    Stokes, David L.; Ubarretxena-Belandia, Iban; Gonen, Tamir; Engel, Andreas

    2013-01-01

    Membrane proteins play a tremendously important role in cell physiology and serve as a target for an increasing number of drugs. Structural information is key to understanding their function and for developing new strategies for combating disease. However, the complex physical chemistry associated with membrane proteins has made them more difficult to study than their soluble cousins. Electron crystallography has historically been a successful method for solving membrane protein structures and has the advantage of providing the natural environment of a lipid membrane. Specifically, when membrane proteins form two-dimensional arrays within a lipid bilayer, images and diffraction can be recorded by electron microscopy. The corresponding data can be combined to produce a three-dimensional reconstruction which, under favorable conditions, can extend to atomic resolution. Like X-ray crystallography, the quality of the structures are very much dependent on the order and size of the crystals. However, unlike X-ray crystallography, high-throughput methods for screening crystallization trials for electron crystallography are not in general use. In this chapter, we describe two alternative and potentially complementary methods for high-throughput screening of membrane protein crystallization within the lipid bilayer. The first method relies on the conventional use of dialysis for removing detergent and thus reconstituting the bilayer; an array of dialysis wells in the standard 96-well format allows the use of a liquid-handling robot and greatly increases throughput. The second method relies on detergent complexation by cyclodextrin; a specialized pipetting robot has been designed not only to titrate cyclodextrin, but to use light scattering to monitor the reconstitution process. In addition, the use of liquid-handling robots for making negatively stained grids and methods for automatically imaging samples in the electron microscope are described. PMID:23132066

  2. High-throughput methods for electron crystallography.

    PubMed

    Stokes, David L; Ubarretxena-Belandia, Iban; Gonen, Tamir; Engel, Andreas

    2013-01-01

    Membrane proteins play a tremendously important role in cell physiology and serve as a target for an increasing number of drugs. Structural information is key to understanding their function and for developing new strategies for combating disease. However, the complex physical chemistry associated with membrane proteins has made them more difficult to study than their soluble cousins. Electron crystallography has historically been a successful method for solving membrane protein structures and has the advantage of providing a native lipid environment for these proteins. Specifically, when membrane proteins form two-dimensional arrays within a lipid bilayer, electron microscopy can be used to collect images and diffraction and the corresponding data can be combined to produce a three-dimensional reconstruction, which under favorable conditions can extend to atomic resolution. Like X-ray crystallography, the quality of the structures are very much dependent on the order and size of the crystals. However, unlike X-ray crystallography, high-throughput methods for screening crystallization trials for electron crystallography are not in general use. In this chapter, we describe two alternative methods for high-throughput screening of membrane protein crystallization within the lipid bilayer. The first method relies on the conventional use of dialysis for removing detergent and thus reconstituting the bilayer; an array of dialysis wells in the standard 96-well format allows the use of a liquid-handling robot and greatly increases throughput. The second method relies on titration of cyclodextrin as a chelating agent for detergent; a specialized pipetting robot has been designed not only to add cyclodextrin in a systematic way, but to use light scattering to monitor the reconstitution process. In addition, the use of liquid-handling robots for making negatively stained grids and methods for automatically imaging samples in the electron microscope are described.

  3. Substandard Antimalarials Available in Afghanistan: A Case for Assessing the Quality of Drugs in Resource Poor Settings

    PubMed Central

    Lalani, Mirza; Kaur, Harparkash; Mohammed, Nader; Mailk, Naiela; van Wyk, Albert; Jan, Sakhi; Kakar, Rishtya Meena; Mojadidi, Mohammed Khalid; Leslie, Toby

    2015-01-01

    Good-quality antimalarials are crucial for the effective treatment and control of malaria. A total of 7,740 individual and packaged tablets, ampoules, and syrups were obtained from 60 randomly selected public (N = 35) and private outlets (N = 25) in Afghanistan. Of these, 134 samples were screened using the Global Pharma Health Fund (GPHF) MiniLab® in Kabul with 33/126 (26%) samples failing the MiniLab® disintegration test. The quality of a subsample (N = 37) of cholorquine, quinine, and sulfadoxine/pyrimethamine tablets was assessed by in vitro dissolution testing following U.S. Pharmacopeia (USP) monographs at a bioanalytical laboratory in London, United Kingdom. Overall, 12/32 (32%) samples of sulfadoxine/pyrimethamine and quinine were found not to comply with the USP tolerance limits. Substandard antimalarials were available in Afghanistan demonstrating that continuous monitoring of drug quality is warranted. However, in Afghanistan as in many low-income countries, capacity to determine and monitor drug quality using methods such as dissolution testing needs to be established to empower national authorities to take appropriate action in setting up legislation and regulation. PMID:25897070

  4. Substandard antimalarials available in Afghanistan: a case for assessing the quality of drugs in resource poor settings.

    PubMed

    Lalani, Mirza; Kaur, Harparkash; Mohammed, Nader; Mailk, Naiela; van Wyk, Albert; Jan, Sakhi; Kakar, Rishtya Meena; Mojadidi, Mohammed Khalid; Leslie, Toby

    2015-06-01

    Good-quality antimalarials are crucial for the effective treatment and control of malaria. A total of 7,740 individual and packaged tablets, ampoules, and syrups were obtained from 60 randomly selected public (N = 35) and private outlets (N = 25) in Afghanistan. Of these, 134 samples were screened using the Global Pharma Health Fund (GPHF) MiniLab® in Kabul with 33/126 (26%) samples failing the MiniLab® disintegration test. The quality of a subsample (N = 37) of cholorquine, quinine, and sulfadoxine/pyrimethamine tablets was assessed by in vitro dissolution testing following U.S. Pharmacopeia (USP) monographs at a bioanalytical laboratory in London, United Kingdom. Overall, 12/32 (32%) samples of sulfadoxine/pyrimethamine and quinine were found not to comply with the USP tolerance limits. Substandard antimalarials were available in Afghanistan demonstrating that continuous monitoring of drug quality is warranted. However, in Afghanistan as in many low-income countries, capacity to determine and monitor drug quality using methods such as dissolution testing needs to be established to empower national authorities to take appropriate action in setting up legislation and regulation.

  5. Substandard antimalarials available in Afghanistan: a case for assessing the quality of drugs in resource poor settings.

    PubMed

    Lalani, Mirza; Kaur, Harparkash; Mohammed, Nader; Mailk, Naiela; van Wyk, Albert; Jan, Sakhi; Kakar, Rishtya Meena; Mojadidi, Mohammed Khalid; Leslie, Toby

    2015-06-01

    Good-quality antimalarials are crucial for the effective treatment and control of malaria. A total of 7,740 individual and packaged tablets, ampoules, and syrups were obtained from 60 randomly selected public (N = 35) and private outlets (N = 25) in Afghanistan. Of these, 134 samples were screened using the Global Pharma Health Fund (GPHF) MiniLab® in Kabul with 33/126 (26%) samples failing the MiniLab® disintegration test. The quality of a subsample (N = 37) of cholorquine, quinine, and sulfadoxine/pyrimethamine tablets was assessed by in vitro dissolution testing following U.S. Pharmacopeia (USP) monographs at a bioanalytical laboratory in London, United Kingdom. Overall, 12/32 (32%) samples of sulfadoxine/pyrimethamine and quinine were found not to comply with the USP tolerance limits. Substandard antimalarials were available in Afghanistan demonstrating that continuous monitoring of drug quality is warranted. However, in Afghanistan as in many low-income countries, capacity to determine and monitor drug quality using methods such as dissolution testing needs to be established to empower national authorities to take appropriate action in setting up legislation and regulation. PMID:25897070

  6. Novel high throughput pooled shRNA screening identifies NQO1 as a potential drug target for host directed therapy for tuberculosis

    PubMed Central

    Li, Qing; Karim, Ahmad F.; Ding, Xuedong; Das, Biswajit; Dobrowolski, Curtis; Gibson, Richard M.; Quiñones-Mateu, Miguel E.; Karn, Jonathan; Rojas, Roxana E.

    2016-01-01

    Chemical regulation of macrophage function is one key strategy for developing host-directed adjuvant therapies for tuberculosis (TB). A critical step to develop these therapies is the identification and characterization of specific macrophage molecules and pathways with a high potential to serve as drug targets. Using a barcoded lentivirus-based pooled short-hairpin RNA (shRNA) library combined with next generation sequencing, we identified 205 silenced host genes highly enriched in mycobacteria-resistant macrophages. Twenty-one of these “hits” belonged to the oxidoreductase functional category. NAD(P)H:quinone oxidoreductase 1 (NQO1) was the top oxidoreductase “hit”. NQO1 expression was increased after mycobacterial infection, and NQO1 knockdown increased macrophage differentiation, NF-κB activation, and the secretion of pro-inflammatory cytokines TNF-α and IL-1β in response to infection. This suggests that mycobacteria hijacks NQO1 to down-regulate pro-inflammatory and anti-bacterial functions. The competitive inhibitor of NQO1 dicoumarol synergized with rifampin to promote intracellular killing of mycobacteria. Thus, NQO1 is a new host target in mycobacterial infection that could potentially be exploited to increase antibiotic efficacy in vivo. Our findings also suggest that pooled shRNA libraries could be valuable tools for genome-wide screening in the search for novel druggable host targets for adjunctive TB therapies. PMID:27297123

  7. Addressing the malaria drug resistance challenge using flow cytometry to discover new antimalarials.

    PubMed

    Grimberg, Brian T; Jaworska, Maria M; Hough, Lindsay B; Zimmerman, Peter A; Phillips, James G

    2009-09-15

    A new flow cytometry method that uses an optimized DNA and RNA staining strategy to monitor the growth and development of the Plasmodium falciparum strain W2mef has been used in a pilot study and has identified Bay 43-9006 1, SU 11274 2, and TMC 125 5 as compounds that exhibit potent (<1 microM) overall and ring stage in vitro antimalarial activity.

  8. Antimalarial Preclinical Drug Development: A Single Oral Dose of A 5-Carbon-linked Trioxane Dimer Plus Mefloquine Cures Malaria-Infected Mice.

    PubMed

    Moon, Deuk Kyu; Singhal, Vandana; Kumar, Nirbhay; Shapiro, Theresa A; Posner, Gary H

    2009-01-01

    Three new 5-carbon-linked trioxane dimer carboxylate esters have been prepared from the natural trioxane, artemisinin in only 3-steps and 40-50% overall yields. Each one of these new chemical entities is at least as efficacious as the clinically used trioxane antimalarial drug artemether when combined with mefloquine hydrochloride in a low single oral dose cure. PMID:20686674

  9. High-Throughput Assay and Discovery of Small Molecules that Interrupt Malaria Transmission.

    PubMed

    Plouffe, David M; Wree, Melanie; Du, Alan Y; Meister, Stephan; Li, Fengwu; Patra, Kailash; Lubar, Aristea; Okitsu, Shinji L; Flannery, Erika L; Kato, Nobutaka; Tanaseichuk, Olga; Comer, Eamon; Zhou, Bin; Kuhen, Kelli; Zhou, Yingyao; Leroy, Didier; Schreiber, Stuart L; Scherer, Christina A; Vinetz, Joseph; Winzeler, Elizabeth A

    2016-01-13

    Preventing transmission is an important element of malaria control. However, most of the current available methods to assay for malaria transmission blocking are relatively low throughput and cannot be applied to large chemical libraries. We have developed a high-throughput and cost-effective assay, the Saponin-lysis Sexual Stage Assay (SaLSSA), for identifying small molecules with transmission-blocking capacity. SaLSSA analysis of 13,983 unique compounds uncovered that >90% of well-characterized antimalarials, including endoperoxides and 4-aminoquinolines, as well as compounds active against asexual blood stages, lost most of their killing activity when parasites developed into metabolically quiescent stage V gametocytes. On the other hand, we identified compounds with consistent low nanomolar transmission-blocking activity, some of which showed cross-reactivity against asexual blood and liver stages. The data clearly emphasize substantial physiological differences between sexual and asexual parasites and provide a tool and starting points for the discovery and development of transmission-blocking drugs.

  10. High-Throughput Assay and Discovery of Small Molecules that Interrupt Malaria Transmission

    PubMed Central

    Plouffe, David M.; Wree, Melanie; Du, Alan Y.; Meister, Stephan; Li, Fengwu; Patra, Kailash; Lubar, Aristea; Okitsu, Shinji L.; Flannery, Erika L.; Kato, Nobutaka; Tanaseichuk, Olga; Comer, Eamon; Zhou, Bin; Kuhen, Kelli; Zhou, Yingyao; Leroy, Didier; Schreiber, Stuart L.; Scherer, Christina A.; Vinetz, Joseph; Winzeler, Elizabeth A.

    2016-01-01

    Summary Preventing transmission is an important element of malaria control. However, most of the current available methods to assay for malaria transmission blocking are relatively low throughput and cannot be applied to large chemical libraries. We have developed a high-throughput and cost-effective assay, the Saponin-lysis Sexual Stage Assay (SaLSSA), for identifying small molecules with transmission-blocking capacity. SaLSSA analysis of 13,983 unique compounds uncovered that >90% of well-characterized antimalarials, including endoperoxides and 4-aminoquinolines, as well as compounds active against asexual blood stages, lost most of their killing activity when parasites developed into metabolically quiescent stage V gametocytes. On the other hand, we identified compounds with consistent low nanomolar transmission-blocking activity, some of which showed cross-reactivity against asexual blood and liver stages. The data clearly emphasize substantial physiological differences between sexual and asexual parasites and provide a tool and starting points for the discovery and development of transmission-blocking drugs. PMID:26749441

  11. Technological advances in high-throughput screening.

    PubMed

    Liu, Bailing; Li, Songjun; Hu, Jie

    2004-01-01

    High-throughput screening (HTS) is the process of testing a large number of diverse chemical structures against disease targets to identify 'hits'. Compared to traditional drug screening methods, HTS is characterized by its simplicity, rapidness, low cost, and high efficiency, taking the ligand-target interactions as the principle, as well as leading to a higher information harvest. As a multidisciplinary field, HTS involves an automated operation-platform, highly sensitive testing system, specific screening model (in vitro), an abundant components library, and a data acquisition and processing system. Various technologies, especially the novel technologies such as fluorescence, nuclear-magnetic resonance, affinity chromatography, surface plasmon resonance, and DNA microarray, are now available, and the screening of more than 100,000 samples per day is already possible. Fluorescence-based assays include the scintillation proximity assay, time-resolved energy transfer, fluorescence anisotropy, fluorescence correlation spectroscopy, and fluorescence fluctuation spectroscopy. Fluorescence-based techniques are likely to be among the most important detection approaches used for HTS due to their high sensitivity and amenability to automation, giving the industry-wide drive to simplify, miniaturize, and speed up assays. The application of NMR technology to HTS is another recent trend in drug research. One advantage afforded by NMR technology is that it can provide direct information on the affinity of the screening compounds and the binding location of protein. The structure-activity relationship acquired from NMR analysis can sharpen the library design, which will be very important in furnishing HTS with well-defined drug candidates. Affinity chromatography used for library screening will provide the information on the fundamental processes of drug action, such as absorption, distribution, excretion, and receptor activation; also the eluting curve can give directly the

  12. High-Throughput Screening in Primary Neurons

    PubMed Central

    Sharma, Punita; Ando, D. Michael; Daub, Aaron; Kaye, Julia A.; Finkbeiner, Steven

    2013-01-01

    Despite years of incremental progress in our understanding of diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), there are still no disease-modifying therapeutics. The discrepancy between the number of lead compounds and approved drugs may partially be a result of the methods used to generate the leads and highlights the need for new technology to obtain more detailed and physiologically relevant information on cellular processes in normal and diseased states. Our high-throughput screening (HTS) system in a primary neuron model can help address this unmet need. HTS allows scientists to assay thousands of conditions in a short period of time which can reveal completely new aspects of biology and identify potential therapeutics in the span of a few months when conventional methods could take years or fail all together. HTS in primary neurons combines the advantages of HTS with the biological relevance of intact, fully differentiated neurons which can capture the critical cellular events or homeostatic states that make neurons uniquely susceptible to disease-associated proteins. We detail methodologies of our primary neuron HTS assay workflow from sample preparation to data reporting. We also discuss our adaptation of our HTS system into high-content screening (HCS), a type of HTS that uses multichannel fluorescence images to capture biological events in situ, and is uniquely suited to study dynamical processes in living cells. PMID:22341232

  13. Natural polyhydroxyalkanoate-gold nanocomposite based biosensor for detection of antimalarial drug artemisinin.

    PubMed

    Phukon, Pinkee; Radhapyari, Keisham; Konwar, Bolin Kumar; Khan, Raju

    2014-04-01

    The worrisome trend of antimalarial resistance has already highlighted the importance of artemisinin as a potent antimalarial agent. The current investigation aimed at fabricating a biosensor based on natural polymer polyhydroxyalkanoate-gold nanoparticle composite mounting on an indium-tin oxide glass plate for the analysis of artemisinin. The biosensor was fabricated using an adsorbing horse-radish peroxidase enzyme on the electrode surface for which cyclic voltammetry was used to monitor the electro-catalytic reduction of artemisinin under diffusion controlled conditions. Electrochemical interfacial properties and immobilization of enzyme onto a polyhydroxyalkanoate-gold nanoparticle film were evaluated, and confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The differential pulse voltammetric peak current for artemisinin was increased linearly (concentration range of 0.01-0.08μg mL(-1)) with sensitivity of 0.26μAμg mL(-1). The greater sensitivity of the fabricated biosensor to artemisinin (optimum limits of detection were 0.0035μg mL(-1) and 0.0036μg mL(-1) in bulk and spiked human serum, respectively) could be of much aid in medical diagnosis. PMID:24582254

  14. Major Reduction in Anti-Malarial Drug Consumption in Senegal after Nation-Wide Introduction of Malaria Rapid Diagnostic Tests

    PubMed Central

    Thiam, Sylla; Thior, Moussa; Faye, Babacar; Ndiop, Médoune; Diouf, Mamadou Lamine; Diouf, Mame Birame; Diallo, Ibrahima; Fall, Fatou Ba; Ndiaye, Jean Louis; Albertini, Audrey; Lee, Evan; Jorgensen, Pernille; Gaye, Oumar; Bell, David

    2011-01-01

    Background While WHO recently recommended universal parasitological confirmation of suspected malaria prior to treatment, debate has continued as to whether wide-scale use of rapid diagnostic tests (RDTs) can achieve this goal. Adherence of health service personnel to RDT results has been poor in some settings, with little impact on anti-malarial drug consumption. The Senegal national malaria control programme introduced universal parasite-based diagnosis using malaria RDTs from late 2007 in all public health facilities. This paper assesses the impact of this programme on anti-malarial drug consumption and disease reporting. Methods and Findings Nationally-collated programme data from 2007 to 2009 including malaria diagnostic outcomes, prescription of artemisinin-based combination therapy (ACT) and consumption of RDTs in public health facilities, were reviewed and compared. Against a marked seasonal variation in all-cause out-patient visits, non-malarial fever and confirmed malaria, parasite-based diagnosis increased nationally from 3.9% of reported malaria-like febrile illness to 86.0% over a 3 year period. The prescription of ACT dropped throughout this period from 72.9% of malaria-like febrile illness to 31.5%, reaching close equivalence to confirmed malaria (29.9% of 584873 suspect fever cases). An estimated 516576 courses of inappropriate ACT prescription were averted. Conclusions The data indicate high adherence of anti-malarial prescribing practice to RDT results after an initial run-in period. The large reduction in ACT consumption enabled by the move from symptom-based to parasite-based diagnosis demonstrates that effective roll-out and use of malaria RDTs is achievable on a national scale through well planned and structured implementation. While more detailed information on management of parasite-negative cases is required at point of care level to assess overall cost-benefits to the health sector, considerable cost-savings were achieved in ACT

  15. Prevalence of Plasmodium falciparum Molecular Markers of Antimalarial Drug Resistance in a Residual Malaria Focus Area in Sabah, Malaysia

    PubMed Central

    Mohd Abd Razak, Mohd Ridzuan; Abdullah, Noor Rain; Sastu, Umi Rubiah; Imwong, Mallika; Muniandy, Prem Kumar; Saat, Muhammad Nor Farhan; Muhammad, Amirrudin; Jelip, Jenarun; Tikuson, Moizin; Yusof, Norsalleh; Rundi, Christina; Mudin, Rose Nani; Syed Mohamed, Ami Fazlin

    2016-01-01

    Chloroquine (CQ) and fansidar (sulphadoxine-pyrimethamine, SP) were widely used for treatment of Plasmodium falciparum for several decades in Malaysia prior to the introduction of Artemisinin-based Combination Therapy (ACT) in 2008. Our previous study in Kalabakan, located in south-east coast of Sabah showed a high prevalence of resistance to CQ and SP, suggesting the use of the treatment may no longer be effective in the area. This study aimed to provide a baseline data of antimalarial drug resistant markers on P. falciparum isolates in Kota Marudu located in the north-east coast of Sabah. Mutations on genes associated with CQ (pfcrt and pfmdr1) and SP (pfdhps and pfdhfr) were assessed by PCR amplification and restriction fragment length polymorphism. Mutations on the kelch13 marker (K13) associated with artemisinin resistance were determined by DNA sequencing technique. The assessment of pfmdr1 copy number variation associated with mefloquine resistant was done by real-time PCR technique. A low prevalence (6.9%) was indicated for both pfcrt K76T and pfmdr1 N86Y mutations. All P. falciparum isolates harboured the pfdhps A437G mutation. Prevalence of pfdhfr gene mutations, S108N and I164L, were 100% and 10.3%, respectively. Combining the different resistant markers, only two isolates were conferred to have CQ and SP treatment failure markers as they contained mutant alleles of pfcrt and pfmdr1 together with quintuple pfdhps/pfdhfr mutation (combination of pfdhps A437G+A581G and pfdhfr C59R+S108N+I164L). All P. falciparum isolates carried single copy number of pfmdr1 and wild type K13 marker. This study has demonstrated a low prevalence of CQ and SP resistance alleles in the study area. Continuous monitoring of antimalarial drug efficacy is warranted and the findings provide information for policy makers in ensuring a proper malaria control. PMID:27788228

  16. 1993 Sir Henry Wellcome Medal and Prize recipient. The rise and fall of mefloquine as an antimalarial drug in South East Asia.

    PubMed

    Shanks, G D

    1994-04-01

    Mefloquine is an antimalarial drug developed by the U.S. Army Antimalarial Drug Program in conjunction with the World Health Organization and Hoffmann-La Roche to address the problem of chloroquine-resistant falciparum malaria encountered during the Vietnam War. Despite the expenditure of millions of dollars over a 20-year period, it is unlikely that mefloquine will ever be used for U.S. soldiers deployed to South East Asia. Although mefloquine met the specifications set by its developers, its usefulness is now limited by the rapid evolution of drug resistance following its release to the civilian population. Drug development for particular military needs was compromised by a rapid biological response from the parasite and commercial concerns. In an era of shrinking military budgets, military drug development programs will by necessity be more resource constrained, thus yielding fewer new drugs per decade. In the short-term, emphasis should be directed toward adapting available antimicrobial drugs for antimalarial purposes. PMID:20058419

  17. Detection and cartography of the fluorinated antimalarial drug mefloquine in normal and Plasmodium falciparum infected red blood cells by scanning ion microscopy and mass spectrometry.

    PubMed

    Adovelande, J; Boulard, Y; Berry, J P; Galle, P; Slodzian, G; Schrével, J

    1994-01-01

    Due to the presence of fluorine atoms in its molecule, the antimalarial drug mefloquine (MQ) can be easily detected in normal and Plasmodium falciparum infected red blood cells (RBC) by scanning ion microscopy and mass spectrometry. The P falciparum infected RBC exhibited intense distribution of MQ inside the parasite. The main compartments of the parasite which accumulate the drug were the food vacuole and the cytoplasm. The correlation between fluorine (19F-) and phosphorus (31P-) as well as probes for the DNA synthesis (BrdU and IdU) emissions shows that the parasite nucleus is also accessible to the drug. This study demonstrates that SIMS technique on smear preparations is an efficient approach for the direct detection and cartography of fluorinated antimalarial drugs in normal and P falciparum infected RBC, without radioactive labelling.

  18. Open Source Drug Discovery: Highly Potent Antimalarial Compounds Derived from the Tres Cantos Arylpyrroles

    PubMed Central

    2016-01-01

    The development of new antimalarial compounds remains a pivotal part of the strategy for malaria elimination. Recent large-scale phenotypic screens have provided a wealth of potential starting points for hit-to-lead campaigns. One such public set is explored, employing an open source research mechanism in which all data and ideas were shared in real time, anyone was able to participate, and patents were not sought. One chemical subseries was found to exhibit oral activity but contained a labile ester that could not be replaced without loss of activity, and the original hit exhibited remarkable sensitivity to minor structural change. A second subseries displayed high potency, including activity within gametocyte and liver stage assays, but at the cost of low solubility. As an open source research project, unexplored avenues are clearly identified and may be explored further by the community; new findings may be cumulatively added to the present work. PMID:27800551

  19. Bayesian models trained with HTS data for predicting β-haematin inhibition and in vitro antimalarial activity

    PubMed Central

    Wicht, Kathryn J.; Combrinck, Jill M.; Smith, Peter J.; Egan, Timothy J.

    2015-01-01

    A large quantity of high throughput screening (HTS) data for antimalarial activity has become available in recent years. This includes both phenotypic and target-based activity. Realising the maximum value of these data remains a challenge. In this respect, methods that allow such data to be used for virtual screening maximise efficiency and reduce costs. In this study both in vitro antimalarial activity and inhibitory data for β-haematin formation, largely obtained from publically available sources, has been used to develop Bayesian models for inhibitors of β-haematin formation and in vitro antimalarial activity. These models were used to screen two in silico compound libraries. In the first, the 1510 U.S. Food and Drug Administration approved drugs available on PubChem were ranked from highest to lowest Bayesian score based on a training set of β-haematin inhibiting compounds active against P. falciparum that did not include any of the clinical antimalarials or close analogues. The six known clinical antimalarials that inhibit β-haematin formation were ranked in the top 2.1% of compounds. Furthermore, the in vitro antimalarial hit-rate for this prioritised set of compounds was found to be 81% in the case of the subset where activity data are available in PubChem. In the second, a library of about 5,000 commercially available compounds (AldrichCPR) was virtually screened for ability to inhibit β-haematin formation and then for in vitro antimalarial activity. A selection of 34 compounds was purchased and tested, of which 24 were predicted to be β-haematin inhibitors. The hit rate for inhibition of β-haematin formation was found to be 25% and a third of these were active against P. falciparum, corresponding to enrichments estimated at about 25- and 140-fold relative to random screening, respectively. PMID:25573118

  20. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy

    PubMed Central

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-01-01

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery. PMID:27294925

  1. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy.

    PubMed

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-06-09

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery.

  2. High-throughput human metabolism and toxicity analysis.

    PubMed

    Lee, Moo-Yeal; Dordick, Jonathan S

    2006-12-01

    Poor drug candidate safety profiles are often identified late in the drug development process, manifesting themselves in the preclinical and clinical phases and significantly contributing to the high cost and low yield of drug discovery. As a result, new tools are needed to accelerate the assessment of drug candidate toxicity and human metabolism earlier in the drug development process, from primary drug candidate screening to lead optimization. Although high-throughput screens exist for much of the discovery phase of drug development, translating such screening techniques into platforms that can accurately mimic the human in vivo response and predict the impact of drug candidates on human toxicology has proven difficult. Nevertheless, some success has been achieved in recent years, which may ultimately yield widespread acceptance in the pharmaceutical industry.

  3. Temporal trends in prevalence of Plasmodium falciparum drug resistance alleles over two decades of changing antimalarial policy in coastal Kenya.

    PubMed

    Okombo, John; Kamau, Alice W; Marsh, Kevin; Sutherland, Colin J; Ochola-Oyier, Lynette Isabella

    2014-12-01

    Molecular surveillance of drug resistance markers through time provides crucial information on genomic adaptations, especially in parasite populations exposed to changing drug pressures. To assess temporal trends of established genotypes associated with tolerance to clinically important antimalarials used in Kenya over the last two decades, we sequenced a region of the pfcrt locus encompassing codons 72-76 of the Plasmodium falciparum chloroquine resistance transporter, full-length pfmdr1 - encoding multi-drug resistance protein, P-glycoprotein homolog (Pgh1) and pfdhfr encoding dihydrofolate reductase, in 485 archived Plasmodium falciparum positive blood samples collected in coastal Kenya at four different time points between 1995 and 2013. Microsatellite loci were also analyzed to compare the genetic backgrounds of parasite populations circulating before and after the withdrawal of chloroquine and sulfadoxine/pyrimethamine. Our results reveal a significant increase in the prevalence of the pfcrt K76 wild-type allele between 1995 and 2013 from 38% to 81.7% (p < 0.0001). In contrast, we noted a significant decline in wild-type pfdhfr S108 allele (p < 0.0001) culminating in complete absence of this allele in 2013. We also observed a significant increase in the prevalence of the wild-type pfmdr1 N86/Y184/D1246 haplotype from 14.6% in 1995 to 66.0% in 2013 (p < 0.0001) and a corresponding decline of the mutant pfmdr1 86Y/184Y/1246Y allele from 36.4% to 0% in 19 years (p < 0.0001). We also show extensive genetic heterogeneity among the chloroquine-sensitive parasites before and after the withdrawal of the drug in contrast to a selective sweep around the triple mutant pfdhfr allele, leading to a mono-allelic population at this locus. These findings highlight the importance of continual surveillance and characterization of parasite genotypes as indicators of the therapeutic efficacy of antimalarials, particularly in the context of changes in malaria treatment

  4. A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs

    PubMed Central

    2013-01-01

    Background Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. Methods A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator. Results Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy

  5. High-throughput titration of luciferase-expressing recombinant viruses.

    PubMed

    Garcia, Vanessa; Krishnan, Ramya; Davis, Colin; Batenchuk, Cory; Le Boeuf, Fabrice; Abdelbary, Hesham; Diallo, Jean-Simon

    2014-01-01

    Standard plaque assays to determine infectious viral titers can be time consuming, are not amenable to a high volume of samples, and cannot be done with viruses that do not form plaques. As an alternative to plaque assays, we have developed a high-throughput titration method that allows for the simultaneous titration of a high volume of samples in a single day. This approach involves infection of the samples with a Firefly luciferase tagged virus, transfer of the infected samples onto an appropriate permissive cell line, subsequent addition of luciferin, reading of plates in order to obtain luminescence readings, and finally the conversion from luminescence to viral titers. The assessment of cytotoxicity using a metabolic viability dye can be easily incorporated in the workflow in parallel and provide valuable information in the context of a drug screen. This technique provides a reliable, high-throughput method to determine viral titers as an alternative to a standard plaque assay.

  6. Direct assembling methodologies for high-throughput bioscreening

    PubMed Central

    Rodríguez-Dévora, Jorge I.; Shi, Zhi-dong; Xu, Tao

    2012-01-01

    Over the last few decades, high-throughput (HT) bioscreening, a technique that allows rapid screening of biochemical compound libraries against biological targets, has been widely used in drug discovery, stem cell research, development of new biomaterials, and genomics research. To achieve these ambitions, scaffold-free (or direct) assembly of biological entities of interest has become critical. Appropriate assembling methodologies are required to build an efficient HT bioscreening platform. The development of contact and non-contact assembling systems as a practical solution has been driven by a variety of essential attributes of the bioscreening system, such as miniaturization, high throughput, and high precision. The present article reviews recent progress on these assembling technologies utilized for the construction of HT bioscreening platforms. PMID:22021162

  7. High-throughput phenotyping of plant shoots.

    PubMed

    Berger, Bettina; de Regt, Bas; Tester, Mark

    2012-01-01

    Advances in automated plant handling and image acquisition now make it possible to use digital imaging for the high-throughput phenotyping of plants. Various traits can be extracted from individual images. However, the potential of this technology lies in the acquisition of time series. Since whole shoot imaging is nondestructive, plants can now be monitored throughout their lifecycle, and dynamic traits such as plant growth and development can be captured and quantified. The technique is applicable to a wide range of plants and research areas and makes high-throughput screens possible, reducing the time and labor needed for the phenotypic characterization of plants.

  8. Rational quality assessment procedure for less-investigated herbal medicines: Case of a Congolese antimalarial drug with an analytical report.

    PubMed

    Tshitenge, Dieudonné Tshitenge; Ioset, Karine Ndjoko; Lami, José Nzunzu; Ndelo-di-Phanzu, Josaphat; Mufusama, Jean-Pierre Koy Sita; Bringmann, Gerhard

    2016-04-01

    Herbal medicines are the most globally used type of medical drugs. Their high cultural acceptability is due to the experienced safety and efficiency over centuries of use. Many of them are still phytochemically less-investigated, and are used without standardization or quality control. Choosing SIROP KILMA, an authorized Congolese antimalarial phytomedicine, as a model case, our study describes an interdisciplinary approach for a rational quality assessment of herbal drugs in general. It combines an authentication step of the herbal remedy prior to any fingerprinting, the isolation of the major constituents, the development and validation of an HPLC-DAD analytical method with internal markers, and the application of the method to several batches of the herbal medicine (here KILMA) thus permitting the establishment of a quantitative fingerprint. From the constitutive plants of KILMA, acteoside, isoacteoside, stachannin A, and pectolinarigenin-7-O-glucoside were isolated, and acteoside was used as the prime marker for the validation of an analytical method. This study contributes to the efforts of the WHO for the establishment of standards enabling the analytical evaluation of herbal materials. Moreover, the paper describes the first phytochemical and analytical report on a marketed Congolese phytomedicine.

  9. A single LC-tandem mass spectrometry method for the simultaneous determination of 14 antimalarial drugs and their metabolites in human plasma.

    PubMed

    Hodel, E M; Zanolari, B; Mercier, T; Biollaz, J; Keiser, J; Olliaro, P; Genton, B; Decosterd, L A

    2009-04-01

    Among the various determinants of treatment response, the achievement of sufficient blood levels is essential for curing malaria. For helping us at improving our current understanding of antimalarial drugs pharmacokinetics, efficacy and toxicity, we have developed a liquid chromatography-tandem mass spectrometry method (LC-MS/MS) requiring 200mul of plasma for the simultaneous determination of 14 antimalarial drugs and their metabolites which are the components of the current first-line combination treatments for malaria (artemether, artesunate, dihydroartemisinin, amodiaquine, N-desethyl-amodiaquine, lumefantrine, desbutyl-lumefantrine, piperaquine, pyronaridine, mefloquine, chloroquine, quinine, pyrimethamine and sulfadoxine). Plasma is purified by a combination of protein precipitation, evaporation and reconstitution in methanol/ammonium formate 20mM (pH 4.0) 1:1. Reverse-phase chromatographic separation of antimalarial drugs is obtained using a gradient elution of 20mM ammonium formate and acetonitrile both containing 0.5% formic acid, followed by rinsing and re-equilibration to the initial solvent composition up to 21min. Analyte quantification, using matrix-matched calibration samples, is performed by electro-spray ionization-triple quadrupole mass spectrometry by selected reaction monitoring detection in the positive mode. The method was validated according to FDA recommendations, including assessment of extraction yield, matrix effect variability, overall process efficiency, standard addition experiments as well as antimalarials short- and long-term stability in plasma. The reactivity of endoperoxide-containing antimalarials in the presence of hemolysis was tested both in vitro and on malaria patients samples. With this method, signal intensity of artemisinin decreased by about 20% in the presence of 0.2% hemolysed red-blood cells in plasma, whereas its derivatives were essentially not affected. The method is precise (inter-day CV%: 3.1-12.6%) and sensitive

  10. Antimalarial natural products: a review

    PubMed Central

    Mojab, Faraz

    2012-01-01

    Objective: Malaria is an infectious disease commonplace in tropical countries. For many years, major antimalarial drugs consisted of natural products, but since 1930s these drugs have been largely replaced with a series of synthetic drugs. This article tries to briefly indicate that some plants which previously were used to treat malaria, as a result of deficiencies of synthetic drugs, have revived into useful products once more. It also attempts to describe some tests which can be used to evaluate plant extracts for antimalarial activity. Materials and Methods: By referring to some recent literatures, data were collected about plants used for the treatment of malaria, evaluation of plant extracts for antimalarial activity, modes of action of natural antimalarial agents, and recent research on antimalarial plants in Iran and other countries. Results and Conclusion: There is an urgent need for the development of new treatments for malaria. Many countries have a vast precedence in the use of medicinal plants and the required knowledge spans many centuries. Although malaria is controlled in Iran, some researchers tend to study malaria and related subjects. In vitro biological tests for the detection of antimalarial activities in plant extracts are currently available. It is vital that the efficacy and safety of traditional medicines be validated and their active constituents be identified in order to establish reliable quality control measures. PMID:25050231

  11. In Vitro and Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity.

    PubMed

    Lucchi, Naomi W; Komino, Franklin; Okoth, Sheila Akinyi; Goldman, Ira; Onyona, Philip; Wiegand, Ryan E; Juma, Elizabeth; Shi, Ya Ping; Barnwell, John W; Udhayakumar, Venkatachalam; Kariuki, Simon

    2015-12-01

    Malaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203 Plasmodium falciparum malaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzed in vitro for sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms in P. falciparum crt (Pfcrt), Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with the Pfcrt wild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P < 0.0001), and higher proportions of parasites with elevated sensitivity to CQ in vitro. The majority of isolates harbored the wild-type N allele in Pfmdr-1 codon 86 (93.5%), with only 7 (3.50%) samples with the N86Y mutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-type Pfmdr-1 D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Y mutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of the Pfmdr-1 gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya.

  12. In Vitro and Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity

    PubMed Central

    Komino, Franklin; Okoth, Sheila Akinyi; Goldman, Ira; Onyona, Philip; Wiegand, Ryan E.; Juma, Elizabeth; Shi, Ya Ping; Barnwell, John W.; Udhayakumar, Venkatachalam; Kariuki, Simon

    2015-01-01

    Malaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203 Plasmodium falciparum malaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzed in vitro for sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms in P. falciparum crt (Pfcrt), Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with the Pfcrt wild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P < 0.0001), and higher proportions of parasites with elevated sensitivity to CQ in vitro. The majority of isolates harbored the wild-type N allele in Pfmdr-1 codon 86 (93.5%), with only 7 (3.50%) samples with the N86Y mutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-type Pfmdr-1 D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Y mutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of the Pfmdr-1 gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya. PMID:26392510

  13. In Vitro and Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity.

    PubMed

    Lucchi, Naomi W; Komino, Franklin; Okoth, Sheila Akinyi; Goldman, Ira; Onyona, Philip; Wiegand, Ryan E; Juma, Elizabeth; Shi, Ya Ping; Barnwell, John W; Udhayakumar, Venkatachalam; Kariuki, Simon

    2015-12-01

    Malaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203 Plasmodium falciparum malaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzed in vitro for sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms in P. falciparum crt (Pfcrt), Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with the Pfcrt wild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P < 0.0001), and higher proportions of parasites with elevated sensitivity to CQ in vitro. The majority of isolates harbored the wild-type N allele in Pfmdr-1 codon 86 (93.5%), with only 7 (3.50%) samples with the N86Y mutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-type Pfmdr-1 D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Y mutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of the Pfmdr-1 gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya. PMID:26392510

  14. Determination of the Cytostatic and Cytocidal Activities of Antimalarial Compounds and their Combination Interactions

    PubMed Central

    Sherlach, Katy S.; Roepe, Paul D.

    2014-01-01

    Determining the antiplasmodial activity of candidate antimalarial drugs in vitro identifies new therapies for drug-resistant malaria. Importantly though, activity can be either growth-inhibitory (cytostatic) or parasite-kill (cytocidal), or both. The simple methods described here can allow for distinction between these, as well as definition of drug interactions between two or more compounds. The latter is important in the definition of novel drug combination therapy for malaria. These methods involve live malarial parasite red blood cell culture, routine pharmacology, high-throughput detection of parasite DNA with fluorescent reporters, and routine mathematical analysis of dose – response curves. The techniques and approaches are accessible to most laboratories and require minimal special equipment beyond a fluorescent plate reader and tissue culture facilities. PMID:25445179

  15. Homology modeling and molecular dynamics simulation of N-myristoyltransferase from Plasmodium falciparum: an insight into novel antimalarial drug design.

    PubMed

    Paul, Paulomi; Chowdhury, Abhishek; Das Talukdar, Anupam; Choudhury, Manabendra Dutta

    2015-03-01

    Malaria is an infectious disease caused by parasites of the genus Plasmodium. It leads to approximately 1 million deaths per annum worldwide, with an increase number of 6.27 million deaths in 2012 alone. Validation of new antimalarial targets is very important in the context of the rise in resistance to current drugs. One such putative target is the enzyme N-myristoyltransferase (NMT), which catalyzes the attachment of the fatty acid myristate to protein substrates (N-myristoylation) for activation. Reports suggests that NMT is an essential and chemically docile target in malaria parasites both in vitro and in vivo, and the selective inhibition of N-myristoylation leads to irreversible failure to form an inner membrane complex—an essential subcellular organelle in the parasite life cycle. In this work, we modeled the three-dimensional structure of Plasmodium falciparum NMT (PfNMT) using Modeler 9.0 taking Plasmodium vivax NMT (PvNMT) as the template. The novelty of the work lies in the selection of template as the similarity of PfNMT with PvNMT was 80.47%, whereas earlier similar work showed template similarity with Candida albicans NMT (CaNMT) and Saccharomyces cerevisiae NMT (ScNMT) to be less than 50%. The generated structure was then validated using various programs such as PROCHECK, RAMPAGE server, CHIMERA and the stability of the model was checked by Gromacs 5.0.

  16. Pharmacokinetics of a novel sublingual spray formulation of the antimalarial drug artemether in African children with malaria.

    PubMed

    Salman, Sam; Bendel, Daryl; Lee, Toong C; Templeton, David; Davis, Timothy M E

    2015-01-01

    The pharmacokinetics of sublingual artemether (ArTiMist) was investigated in 91 young African children with severe malaria or who could not tolerate oral antimalarial therapy. Each received 3.0 mg/kg of body weight of artemether at 0, 8, 24, 36, 48, and 60 h or until the initiation of oral treatment. Few blood samples were drawn postdose. Plasma artemether and dihydroartemisinin (DHA) levels were measured using liquid chromatography-mass spectrometry, and the data were analyzed using established population compartmental pharmacokinetic models. Parasite clearance was prompt (median parasite clearance time, 24 h), and there were no serious adverse events. Consistent with studies in healthy adults (S. Salman, D. Bendel, T. C. Lee, D. Templeton, and T. M. E. Davis, Antimicrob Agents Chemother 59:3197-3207, 2015, http://dx.doi.org/10.1128/AAC.05013-14), the absorption of sublingual artemether was biphasic, and multiple dosing was associated with the autoinduction of the metabolism of artemether to DHA (which itself has potent antimalarial activity). In contrast to studies using healthy volunteers, pharmacokinetic modeling indicated that the first absorption phase did not avoid first-pass metabolism, suggesting that the drug is transferred to the upper intestine through postdose fluid/food intake. Simulations using the present data and those from an earlier study in older Melanesian children with uncomplicated malaria treated with artemether-lumefantrine tablets suggested that the bioavailability of sublingual artemether was at least equivalent to that after conventional oral artemether-lumefantrine (median [interquartile range] areas under the concentration-time curve for artemether, 3,403 [2,471 to 4,771] versus 3,063 [2,358 to 4,514] μg · h/liter, respectively; and for DHA, 2,958 [2,146 to 4,278] versus 2,839 [1,812 to 3,488] μg · h/liter, respectively; P ≥ 0.42). These findings suggest that sublingual artemether could be used as prereferral treatment for sick

  17. Assessment of the Worldwide Antimalarial Resistance Network Standardized Procedure for In Vitro Malaria Drug Sensitivity Testing Using SYBR Green Assay for Field Samples with Various Initial Parasitemia Levels

    PubMed Central

    Cheruiyot, Agnes C.; Auschwitz, Jennifer M.; Lee, Patricia J.; Yeda, Redemptah A.; Okello, Charles O.; Leed, Susan E.; Talwar, Mayank; Murthy, Tushar; Gaona, Heather W.; Hickman, Mark R.; Akala, Hoseah M.; Kamau, Edwin

    2016-01-01

    The malaria SYBR green assay, which is used to profile in vitro drug susceptibility of Plasmodium falciparum, is a reliable drug screening and surveillance tool. Malaria field surveillance efforts provide isolates with various low levels of parasitemia. To be advantageous, malaria drug sensitivity assays should perform reproducibly among various starting parasitemia levels rather than at one fixed initial value. We examined the SYBR green assay standardized procedure developed by the Worldwide Antimalarial Resistance Network (WWARN) for its sensitivity and ability to accurately determine the drug concentration that inhibits parasite growth by 50% (IC50) in samples with a range of initial parasitemia levels. The initial sensitivity determination of the WWARN procedure yielded a detection limit of 0.019% parasitemia. P. falciparum laboratory strains and field isolates with various levels of initial parasitemia were then subjected to a range of doses of common antimalarials. The IC50s were comparable for laboratory strains with between 0.0375% and 0.6% parasitemia and for field isolates with between 0.075% and 0.6% parasitemia for all drugs tested. Furthermore, assay quality (Z′) analysis indicated that the WWARN procedure displays high robustness, allowing for drug testing of malaria field samples within the derived range of initial parasitemia. The use of the WWARN procedure should allow for the inclusion of more malaria field samples in malaria drug sensitivity screens that would have otherwise been excluded due to low initial parasitemia levels. PMID:26856829

  18. Structural mapping of the ClpB ATPases of Plasmodium falciparum: Targeting protein folding and secretion for antimalarial drug design

    PubMed Central

    AhYoung, Andrew P; Koehl, Antoine; Cascio, Duilio; Egea, Pascal F

    2015-01-01

    Caseinolytic chaperones and proteases (Clp) belong to the AAA+ protein superfamily and are part of the protein quality control machinery in cells. The eukaryotic parasite Plasmodium falciparum, the causative agent of malaria, has evolved an elaborate network of Clp proteins including two distinct ClpB ATPases. ClpB1 and ClpB2 are involved in different aspects of parasitic proteostasis. ClpB1 is present in the apicoplast, a parasite-specific and plastid-like organelle hosting various metabolic pathways necessary for parasite growth. ClpB2 localizes to the parasitophorous vacuole membrane where it drives protein export as core subunit of a parasite-derived protein secretion complex, the Plasmodium Translocon of Exported proteins (PTEX); this process is central to parasite virulence and survival in the human host. The functional associations of these two chaperones with parasite-specific metabolism and protein secretion make them prime drug targets. ClpB proteins function as unfoldases and disaggregases and share a common architecture consisting of four domains—a variable N-terminal domain that binds different protein substrates, followed by two highly conserved catalytic ATPase domains, and a C-terminal domain. Here, we report and compare the first crystal structures of the N terminal domains of ClpB1 and ClpB2 from Plasmodium and analyze their molecular surfaces. Solution scattering analysis of the N domain of ClpB2 shows that the average solution conformation is similar to the crystalline structure. These structures represent the first step towards the characterization of these two malarial chaperones and the reconstitution of the entire PTEX to aid structure-based design of novel anti-malarial drugs. PMID:26130467

  19. Viral detection by high-throughput sequencing.

    PubMed

    Motooka, Daisuke; Nakamura, Shota; Hagiwara, Katsuro; Nakaya, Takaaki

    2015-01-01

    We applied a high-throughput sequencing platform, Ion PGM, for viral detection in fecal samples from adult cows collected in Hokkaido, Japan. Random RT-PCR was performed to amplify RNA extracted from 0.25 ml of fecal specimens (N = 8), and more than 5 μg of cDNA was synthesized. Unbiased high-throughput sequencing using the 318 v2 semiconductor chip of these eight samples yielded 57-580 K (average: 270 K, after data analysis) reads in a single run. As a result, viral genome sequences were detected in each specimen. In addition to bacteriophage, mammal- and insect-derived viruses, partial genome sequences of plant, algal, and protozoal viruses were detected. Thus, this metagenomic analysis of fecal specimens could be useful to comprehensively understand viral populations of the intestine and food sources in animals. PMID:25287501

  20. Microfabricated high-throughput electronic particle detector.

    PubMed

    Wood, D K; Requa, M V; Cleland, A N

    2007-10-01

    We describe the design, fabrication, and use of a radio frequency reflectometer integrated with a microfluidic system, applied to the very high-throughput measurement of micron-scale particles, passing in a microfluidic channel through the sensor region. The device operates as a microfabricated Coulter counter [U.S. Patent No. 2656508 (1953)], similar to a design we have described previously, but here with significantly improved electrode geometry as well as including electronic tuning of the reflectometer; the two improvements yielding an improvement by more than a factor of 10 in the signal to noise and in the diametric discrimination of single particles. We demonstrate the high-throughput discrimination of polystyrene beads with diameters in the 4-10 microm range, achieving diametric resolutions comparable to the intrinsic spread of diameters in the bead distribution, at rates in excess of 15 x 10(6) beads/h.

  1. Viral detection by high-throughput sequencing.

    PubMed

    Motooka, Daisuke; Nakamura, Shota; Hagiwara, Katsuro; Nakaya, Takaaki

    2015-01-01

    We applied a high-throughput sequencing platform, Ion PGM, for viral detection in fecal samples from adult cows collected in Hokkaido, Japan. Random RT-PCR was performed to amplify RNA extracted from 0.25 ml of fecal specimens (N = 8), and more than 5 μg of cDNA was synthesized. Unbiased high-throughput sequencing using the 318 v2 semiconductor chip of these eight samples yielded 57-580 K (average: 270 K, after data analysis) reads in a single run. As a result, viral genome sequences were detected in each specimen. In addition to bacteriophage, mammal- and insect-derived viruses, partial genome sequences of plant, algal, and protozoal viruses were detected. Thus, this metagenomic analysis of fecal specimens could be useful to comprehensively understand viral populations of the intestine and food sources in animals.

  2. High throughput network for multiprocessor interconnections

    NASA Astrophysics Data System (ADS)

    Raatikainen, Pertti; Zidbeck, Juha

    1993-05-01

    Multiprocessor architectures are needed to support modern broadband applications, since traditional bus structures are not capable of providing high throughput. New bus structures are needed, especially in the area of network components and terminals. A study to find an efficient and cost effective interconnection topology for the future high speed products is presented. The most common bus topologies are introduced, and their characteristics are estimated to decide which one of them offers best performance and lowest implementation cost. The ring topology is chosen to be studied in more detail. Four competing bus access schemes for the high throughput ring are introduced as well as simulation models for each of them. Using transfer delay and throughput results, as well as keeping the implementation point of view in mind, the best candidate is selected to be studied and experimented in the succeeding research project.

  3. Assessment of the Worldwide Antimalarial Resistance Network Standardized Procedure for In Vitro Malaria Drug Sensitivity Testing Using SYBR Green Assay for Field Samples with Various Initial Parasitemia Levels.

    PubMed

    Cheruiyot, Agnes C; Auschwitz, Jennifer M; Lee, Patricia J; Yeda, Redemptah A; Okello, Charles O; Leed, Susan E; Talwar, Mayank; Murthy, Tushar; Gaona, Heather W; Hickman, Mark R; Akala, Hoseah M; Kamau, Edwin; Johnson, Jacob D

    2016-04-01

    The malaria SYBR green assay, which is used to profilein vitrodrug susceptibility ofPlasmodium falciparum, is a reliable drug screening and surveillance tool. Malaria field surveillance efforts provide isolates with various low levels of parasitemia. To be advantageous, malaria drug sensitivity assays should perform reproducibly among various starting parasitemia levels rather than at one fixed initial value. We examined the SYBR green assay standardized procedure developed by the Worldwide Antimalarial Resistance Network (WWARN) for its sensitivity and ability to accurately determine the drug concentration that inhibits parasite growth by 50% (IC50) in samples with a range of initial parasitemia levels. The initial sensitivity determination of the WWARN procedure yielded a detection limit of 0.019% parasitemia.P. falciparumlaboratory strains and field isolates with various levels of initial parasitemia were then subjected to a range of doses of common antimalarials. The IC50s were comparable for laboratory strains with between 0.0375% and 0.6% parasitemia and for field isolates with between 0.075% and 0.6% parasitemia for all drugs tested. Furthermore, assay quality (Z') analysis indicated that the WWARN procedure displays high robustness, allowing for drug testing of malaria field samples within the derived range of initial parasitemia. The use of the WWARN procedure should allow for the inclusion of more malaria field samples in malaria drug sensitivity screens that would have otherwise been excluded due to low initial parasitemia levels.

  4. High-throughput neuro-imaging informatics

    PubMed Central

    Miller, Michael I.; Faria, Andreia V.; Oishi, Kenichi; Mori, Susumu

    2013-01-01

    This paper describes neuroinformatics technologies at 1 mm anatomical scale based on high-throughput 3D functional and structural imaging technologies of the human brain. The core is an abstract pipeline for converting functional and structural imagery into their high-dimensional neuroinformatic representation index containing O(1000–10,000) discriminating dimensions. The pipeline is based on advanced image analysis coupled to digital knowledge representations in the form of dense atlases of the human brain at gross anatomical scale. We demonstrate the integration of these high-dimensional representations with machine learning methods, which have become the mainstay of other fields of science including genomics as well as social networks. Such high-throughput facilities have the potential to alter the way medical images are stored and utilized in radiological workflows. The neuroinformatics pipeline is used to examine cross-sectional and personalized analyses of neuropsychiatric illnesses in clinical applications as well as longitudinal studies. We demonstrate the use of high-throughput machine learning methods for supporting (i) cross-sectional image analysis to evaluate the health status of individual subjects with respect to the population data, (ii) integration of image and personal medical record non-image information for diagnosis and prognosis. PMID:24381556

  5. High-Throughput Screening Uncovers Novel Botulinum Neurotoxin Inhibitor Chemotypes.

    PubMed

    Bompiani, Kristin M; Caglič, Dejan; Krutein, Michelle C; Benoni, Galit; Hrones, Morgan; Lairson, Luke L; Bian, Haiyan; Smith, Garry R; Dickerson, Tobin J

    2016-08-01

    Botulism is caused by potent and specific bacterial neurotoxins that infect host neurons and block neurotransmitter release. Treatment for botulism is limited to administration of an antitoxin within a short time window, before the toxin enters neurons. Alternatively, current botulism drug development targets the toxin light chain, which is a zinc-dependent metalloprotease that is delivered into neurons and mediates long-term pathology. Several groups have identified inhibitory small molecules, peptides, or aptamers, although no molecule has advanced to the clinic due to a lack of efficacy in advanced models. Here we used a homogeneous high-throughput enzyme assay to screen three libraries of drug-like small molecules for new chemotypes that modulate recombinant botulinum neurotoxin light chain activity. High-throughput screening of 97088 compounds identified numerous small molecules that activate or inhibit metalloprotease activity. We describe four major classes of inhibitory compounds identified, detail their structure-activity relationships, and assess their relative inhibitory potency. A previously unreported chemotype in any context of enzyme inhibition is described with potent submicromolar inhibition (Ki = 200-300 nM). Additional detailed kinetic analyses and cellular cytotoxicity assays indicate the best compound from this series is a competitive inhibitor with cytotoxicity values around 4-5 μM. Given the potency and drug-like character of these lead compounds, further studies, including cellular activity assays and DMPK analysis, are justified. PMID:27314875

  6. Determination of log P values of new cyclen based antimalarial drug leads using RP-HPLC.

    PubMed

    Rudraraju, A V; Amoyaw, P N A; Hubin, T J; Khan, M O F

    2014-09-01

    Lipophilicity, expressed by log P, is an important physicochemical property of drugs that affects many biological processes, including drug absorption and distribution. The main purpose of this study to determine the log P values of newly discovered drug leads using reversed-phase high-performance liquid chromatography (RP-HPLC). The reference standards, with varying polarity ranges, were dissolved in methanol and analyzed by RP-HPLC using a C18 column. The mobile phase consisted of a mixture of acetonitrile, methanol and water in a gradient elution mode. A calibration curve was plotted between the experimental log P values and obtained log k values of the reference standard compounds and a best fit line was obtained. The log k values of the new drug leads were determined in the same solvent system and were used to calculate the respective log P values by using the best fit equation. The log P vs. log k data gave a best fit linear curve that had an R2 of 0.9786 with Pvalues of the intercept and slope of 1.19 x 10(-6) and 1.56 x 10(-10), respectively, at 0.05 level of significance. Log P values of 15 new drug leads and related compounds, all of which are derivatives of macrocyclic polyamines and their metal complexes, were determined. The values obtained are closely related to the calculated log P (Clog P) values using ChemDraw Ultra 12.0. This experiment provided efficient, fast and reasonable estimates of log P values of the new drug leads by using RP-HPLC.

  7. A Physico-Biochemical Study on Potential Redox-Cyclers as Antimalarial and Antischistosomal Drugs

    PubMed Central

    Johann, Laure; Lanfranchi, Don Antoine; Davioud-Charvet, Elisabeth; Elhabiri, Mourad

    2013-01-01

    The role of redox enzymes in establishing a microenvironment for parasite development is well characterized. Mimicking human glucose-6-phosphate dehydrogenase and glutathione reductase (GR) deficiencies by redox-cycling compounds thus represents a challenge to the design of new preclinical antiparasitic drug candidates. Schistosomes and malarial parasites feed on hemoglobin. Heme, the toxic prosthetic group of the protein, is not digested and represents a challenge to the redox metabolism of the parasites. Here, we report on old and new redox-cycling compounds – whose antiparasitic activities are related to their interference with (met)hemoglobin degradation and hematin crystallization. Three key-assays allowed probing and differentiating the mechanisms of drug actions. Inhibition of β-hematin was first compared to the heme binding as a possible mode of action. All tested ligands interact with the hematin π-π dimer with KD similar to those measured for the major antiparasitic drugs. No correlation between a high affinity for hematin and the capacity to prevent β-hematin formation was however deduced. Inhibition of β-hematin formation is consequently not the result of a single process but results from redox processes following electron transfers from the drugs to iron(III)-containing targets. The third experiment highlighted that several redox-active compounds (in their reduced forms) are able to efficiently reduce methemoglobin to hemoglobin in a GR/NADPH-coupled assay. A correlation between methemoglobin reduction and inhibition of β-hematin was shown, demonstrating that both processes are closely related. The ability of our redox-cyclers to trigger methemoglobin reduction therefore constitutes a critical step to understand the mechanism of action of our drug candidates. PMID:22607146

  8. Epidemic of Plasmodium falciparum malaria involving substandard antimalarial drugs, Pakistan, 2003.

    PubMed

    Leslie, Toby; Kaur, Harpakash; Mohammed, Nasir; Kolaczinski, Kate; Ord, Rosalynn L; Rowland, Mark

    2009-11-01

    Because of instability in eastern Afghanistan, new refugees crossed into the federally administered tribal areas of northwestern Pakistan in 2002. In 2003, we investigated an epidemic of Plasmodium falciparum malaria in 1 of the camps. Incidence was 100.4 cases/1,000 person-years; in other nearby camps it was only 2.1/1,000 person-years. Anopheline mosquitoes were found despite an earlier spray campaign. Documented clinical failures at the basic health unit prompted a drug resistance survey of locally manufactured sulfadoxine-pyrimethamine used for routine treatment. The in vivo failure rate was 28.5%. PCR analysis of the P. falciparum dihydrofolate reductase and dihyropteroate synthase genes showed no mutations associated with clinical failure. However, chemical analysis of the drug showed that it was substandard. As global incidence decreases and epidemics become more of a threat, enhanced quality assurance of control interventions is essential. PMID:19891862

  9. Epidemic of Plasmodium falciparum Malaria Involving Substandard Antimalarial Drugs, Pakistan, 2003

    PubMed Central

    Kaur, Harpakash; Mohammed, Nasir; Kolaczinski, Kate; Ord, Rosalynn L.; Rowland, Mark

    2009-01-01

    Because of instability in eastern Afghanistan, new refugees crossed into the federally administered tribal areas of northwestern Pakistan in 2002. In 2003, we investigated an epidemic of Plasmodium falciparum malaria in 1 of the camps. Incidence was 100.4 cases/1,000 person-years; in other nearby camps it was only 2.1/1,000 person-years. Anopheline mosquitoes were found despite an earlier spray campaign. Documented clinical failures at the basic health unit prompted a drug resistance survey of locally manufactured sulfadoxine-pyrimethamine used for routine treatment. The in vivo failure rate was 28.5%. PCR analysis of the P. falciparum dihydrofolate reductase and dihyropteroate synthase genes showed no mutations associated with clinical failure. However, chemical analysis of the drug showed that it was substandard. As global incidence decreases and epidemics become more of a threat, enhanced quality assurance of control interventions is essential. PMID:19891862

  10. Luciferase-Based, High-Throughput Assay for Screening and Profiling Transmission-Blocking Compounds against Plasmodium falciparum Gametocytes.

    PubMed

    Lucantoni, Leonardo; Fidock, David A; Avery, Vicky M

    2016-04-01

    The discovery of new antimalarial drugs able to target both the asexual and gametocyte stages ofPlasmodium falciparumis critical to the success of the malaria eradication campaign. We have developed and validated a robust, rapid, and cost-effective high-throughput reporter gene assay to identify compounds active against late-stage (stage IV and V) gametocytes. The assay, which is suitable for testing compound activity at incubation times up to 72 h, demonstrates excellent quality and reproducibility, with averageZ' values of 0.85 ± 0.01. We used the assay to screen more than 10,000 compounds from three chemically diverse libraries. The screening outcomes highlighted the opportunity to use collections of compounds with known activity against the asexual stages of the parasites as a starting point for gametocytocidal activity detection in order to maximize the chances of identifying gametocytocidal compounds. This assay extends the capabilities of our previously reported luciferase assay, which tested compounds against early-stage gametocytes, and opens possibilities to profile the activities of gametocytocidal compounds over the entire course of gametocytogenesis. PMID:26787698

  11. Luciferase-Based, High-Throughput Assay for Screening and Profiling Transmission-Blocking Compounds against Plasmodium falciparum Gametocytes

    PubMed Central

    Lucantoni, Leonardo; Fidock, David A.

    2016-01-01

    The discovery of new antimalarial drugs able to target both the asexual and gametocyte stages of Plasmodium falciparum is critical to the success of the malaria eradication campaign. We have developed and validated a robust, rapid, and cost-effective high-throughput reporter gene assay to identify compounds active against late-stage (stage IV and V) gametocytes. The assay, which is suitable for testing compound activity at incubation times up to 72 h, demonstrates excellent quality and reproducibility, with average Z′ values of 0.85 ± 0.01. We used the assay to screen more than 10,000 compounds from three chemically diverse libraries. The screening outcomes highlighted the opportunity to use collections of compounds with known activity against the asexual stages of the parasites as a starting point for gametocytocidal activity detection in order to maximize the chances of identifying gametocytocidal compounds. This assay extends the capabilities of our previously reported luciferase assay, which tested compounds against early-stage gametocytes, and opens possibilities to profile the activities of gametocytocidal compounds over the entire course of gametocytogenesis. PMID:26787698

  12. Inhibition of native 5-HT3 receptor-evoked contractions in guinea pig and mouse ileum by antimalarial drugs.

    PubMed

    Kelley, Stephen P; Walsh, Jacqueline; Kelly, Mark C; Muhdar, Simerjyot; Adel-Aziz, Mohammed; Barrett, Iain D; Wildman, Scott S

    2014-09-01

    Quinine, chloroquine and mefloquine are commonly used to treat malaria, however, with associated gastrointestinal (GI) side-effects. These drugs act as antagonists at recombinant 5-HT3 receptors and modulate gut peristalsis. These gastrointestinal side effects may be the result of antagonism at intestinal 5-HT3 receptors. Ileum from male C57BL/6 mice and guinea pigs was mounted longitudinally in organ baths. The concentration-response curves for 5-HT and the selective 5-HT3 agonist 2-Me-5-HT were obtained with 5-HT (pEC50 = 7.57 ± 0.33, 12) more potent (P = 0.004) than 2-Me-5-HT (pEC50 = 5.45 ± 0.58, n = 5) in mouse ileum. There was no difference in potency of 5-HT (pEC50 = 5.42 ± 0.15, n = 8) and 2-Me-5-HT (pIC50 = 5.01 ± 0.55, n = 11) in guinea pig ileum (P > 0.05). Quinine, chloroquine or mefloquine was applied for 10 min and inhibitions prior to submaximal agonist application. In mouse ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 4.9 ± 0.17, n = 7; 4.76 ± 0.14, n = 5; 6.21 ± 0.2, n = 4, correspondingly) with mefloquine most potent (P < 0.05). Quinine, chloroquine and mefloquine antagonised 2-me-5-HT-induced contractions (pIC50 = 6.35 ± 0.11, n = 8; 4.64 ± 0.2, n = 7; 5.11 ± 0.22, n = 6, correspondingly) with quinine most potent (P < 0.05). In guinea-pig ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 5.02 ± 0.15, n = 6; 4.54 ± 0.1, n = 7; 5.32 ± 0.13, n = 5) and 2-me-5-HT-induced contractions (pIC50 = 4.62 ± 0.25, n = 5; 4.56 ± 0.14, n = 6; 5.67 ± 0.12, n = 4) with chloroquine least potent against 5-HT and mefloquine most potent against 2-me-5-HT (P < 0.05). These results support previous studies identifying anti-malarial drugs as antagonists at recombinant 5-HT3 receptors and may also demonstrate the ability of these drugs to influence native 5-HT3 receptor-evoked contractile responses which may account for their associated GI side-effects. PMID:24886883

  13. High Throughput Screening For Hazard and Risk of Environmental Contaminants

    EPA Science Inventory

    High throughput toxicity testing provides detailed mechanistic information on the concentration response of environmental contaminants in numerous potential toxicity pathways. High throughput screening (HTS) has several key advantages: (1) expense orders of magnitude less than an...

  14. High-throughput siRNA-based functional target validation.

    PubMed

    Xin, Hong; Bernal, Alejandro; Amato, Frank A; Pinhasov, Albert; Kauffman, Jack; Brenneman, Douglas E; Derian, Claudia K; Andrade-Gordon, Patricia; Plata-Salamán, Carlos R; Ilyin, Sergey E

    2004-06-01

    The drug discovery process pursued by major pharmaceutical companies for many years starts with target identification followed by high-throughput screening (HTS) with the goal of identifying lead compounds. To accomplish this goal, significant resources are invested into automation of the screening process or HTS. Robotic systems capable of handling thousands of data points per day are implemented across the pharmaceutical sector. Many of these systems are amenable to handling cell-based screening protocols as well. On the other hand, as companies strive to develop innovative products based on novel mechanisms of action(s), one of the current bottlenecks of the industry is the target validation process. Traditionally, bioinformatics and HTS groups operate separately at different stages of the drug discovery process. The authors describe the convergence and integration of HTS and bioinformatics to perform high-throughput target functional identification and validation. As an example of this approach, they initiated a project with a functional cell-based screen for a biological process of interest using libraries of small interfering RNA (siRNA) molecules. In this protocol, siRNAs function as potent gene-specific inhibitors. siRNA-mediated knockdown of the target genes is confirmed by TaqMan analysis, and genes with impacts on biological functions of interest are selected for further analysis. Once the genes are confirmed and further validated, they may be used for HTS to yield lead compounds.

  15. Malaria Related Perceptions, Care Seeking after Onset of Fever and Anti-Malarial Drug Use in Malaria Endemic Settings of Southwest Ethiopia

    PubMed Central

    Birhanu, Zewdie; Abebe, Lakew; Sudhakar, Morankar; Dissanayake, Gunawardena; Yihdego, Yemane Ye-ebiyo; Alemayehu, Guda; Yewhalaw, Delenasaw

    2016-01-01

    Background Prompt care seeking and appropriate use of anti-malarial drugs are critical components of malaria prevention and control. This study assessed malaria related perceptions, care seeking behavior and anti-malarial drug use in malaria endemic settings of Ethiopia. Methods Data were generated from a community based cross-sectional study conducted among 798 households during January 2014 as part of a larger household behavioral study in three malaria endemic districts of Jimma Zone, Southwest Ethiopia. Both quantitative and qualitative data were collected and analyzed using SPSS 17.0 and STATA 12.0. Results In this study, only 76.1% of the respondents associated malaria to mosquito bite, and incorrect beliefs and perceptions were noted. Despite moderate level of knowledge (estimated mean = 62.2, Std Err = 0.7, 95% CI: 60.6–63.8%), quite high favorable attitude (overall estimated mean = 91.5, Std Err = 0.6, 95% CI: 90.1–92.9%) were recorded towards malaria preventive measures. The mean attitude score for prompt care seeking, appropriate use of anti-malarial drugs, LLIN use and Indoor Residual Spray acceptance was 98.5 (Std Err = 0.4, 95% CI:97.5–99.4), 92.7 (Std Err = 0.6 95% CI:91.5–93.9), 88.8 (Std Err = 0.5, 95% CI:85.5–92.1) and 86.5 (Std Err = 1.2, 95% CI: 83.9–89.1), respectively. The prevalence of fever was 2.9% (116/4107) and of the study participants with fever, 71.9% (95% CI: 65.5–78.3%) sought care and all of them consulted formal health care system. However, only 17 (19.8%) sought care within 24 hours after onset of fever. The frequency of care seeking was higher (77.8%, n = 21/27) and more prompt (28.6%, 6/21) for children under five as compared to old age groups despite it was not statistically significant (p > 0.05). However, higher median time of seeking first care was observed among Muslims and people who did not attend school (p < 0.05). Of those who used anti-malarial drugs, 9.1% indicated that they used it inappropriately

  16. High throughput chemical munitions treatment system

    DOEpatents

    Haroldsen, Brent L.; Stofleth, Jerome H.; Didlake, Jr., John E.; Wu, Benjamin C-P

    2011-11-01

    A new High-Throughput Explosive Destruction System is disclosed. The new system is comprised of two side-by-side detonation containment vessels each comprising first and second halves that feed into a single agent treatment vessel. Both detonation containment vessels further comprise a surrounding ventilation facility. Moreover, the detonation containment vessels are designed to separate into two half-shells, wherein one shell can be moved axially away from the fixed, second half for ease of access and loading. The vessels are closed by means of a surrounding, clam-shell type locking seal mechanisms.

  17. Clustering of High Throughput Gene Expression Data

    PubMed Central

    Pirim, Harun; Ekşioğlu, Burak; Perkins, Andy; Yüceer, Çetin

    2012-01-01

    High throughput biological data need to be processed, analyzed, and interpreted to address problems in life sciences. Bioinformatics, computational biology, and systems biology deal with biological problems using computational methods. Clustering is one of the methods used to gain insight into biological processes, particularly at the genomics level. Clearly, clustering can be used in many areas of biological data analysis. However, this paper presents a review of the current clustering algorithms designed especially for analyzing gene expression data. It is also intended to introduce one of the main problems in bioinformatics - clustering gene expression data - to the operations research community. PMID:23144527

  18. Using genetic methods to define the targets of compounds with antimalarial activity

    PubMed Central

    Flannery, Erika L.; Fidock, David A.; Winzeler, Elizabeth A.

    2013-01-01

    Although phenotypic cellular screening has been used to drive antimalarial drug discovery in recent years, in some cases target-based drug discovery remains more attractive. This is especially true when appropriate high-throughput cellular assays are lacking, as is the case for drug discovery efforts that aim to provide a replacement for primaquine (4-N-(6-methoxyquinolin-8-yl)pentane-1,4-diamine), the only drug that can block Plasmodium transmission to Anopheles mosquitoes and eliminate liver-stage hypnozoites. At present, however, there are no known chemically validated parasite protein targets that are important in all Plasmodium parasite developmental stages and that can be used in traditional biochemical compound screens. We propose that a plethora of novel, chemically validated, cross-stage antimalarial targets still remain to be discovered from the ~5,500 proteins encoded by the Plasmodium genomes. Here we discuss how in vitro evolution of drug-resistant strains of Plasmodium falciparum and subsequent whole-genome analysis can be used to find the targets of some of the many compounds discovered in whole-cell phenotypic screens. PMID:23927658

  19. Molecular diagnosis of resistance to antimalarial drugs during epidemics and in war zones.

    PubMed

    Djimdé, Abdoulaye A; Dolo, Amagana; Ouattara, Amed; Diakité, Sira; Plowe, Christopher V; Doumbo, Ogobara K

    2004-08-15

    Plasmodium falciparum mutations pfcrt K76T and the dhfr/dhps "quintuple mutant" are molecular markers of resistance to chloroquine and sulfadoxine-pyrimethamine, respectively. During an epidemic of P. falciparum malaria in an area of political unrest in northern Mali, where standard efficacy studies have been impossible, we measured the prevalence of these markers in a cross-sectional survey. In 80% of cases of infection, pfcrt K76T was detected, but none of the cases carried the dhfr/dhps quintuple mutant. On the basis of these results, chloroquine was replaced by sulfadoxine-pyrimethamine in control efforts. This example illustrates how molecular markers for drug resistance can provide timely data that inform malaria-control policy during epidemics and other emergency situations.

  20. Assessment of causal prophylactic activity in Plasmodium berghei yoelii and its value for the development of new antimalarial drugs*

    PubMed Central

    Fink, E.

    1974-01-01

    The causal prophylactic activity of several reference and experimental antimalarial compounds was assessed in sporozoite-induced infections of NMRI mice with Plasmodium berghei yoelii (strain 17X). The animals were inoculated with 10 000 sporozoites per mouse and treated once 2-4 hours later. The test system has proved to be very suitable in experiments involving more than 3 000 mice. The infection rate in 448 untreated controls was 97.3%. Lowering the sporozoite content of the inoculum to 1 000 or 100 sporozoites markedly reduced the rate (65.1% and 32.7%). In experiments with primaquine the causal prophylactic activity was also influenced by the time of drug administration before or after sporozoite inoculation. No causal prophylactic effect was demonstrable with quinine, chloroquine, amodiaquine, amopyroquine, RC-12, or B 505. Primaquine was active, but pamaquine and pentaquine were only sporadically active. The pre-erythrocytic stages of P. b. yoelii were only slightly sensitive to dapsone, sulfadiazine, and sulformethoxine; they were 10-100 times more susceptible to proguanil, cycloguanil, and pyrimethamine. The experimental 6-aminoquinolines NI 147/36, NI 187/82, and BA 138/111 and the 7-chlorolincomycin derivative U 24729 were also studied. Experiments in which curative activity against blood-induced infections of P. b. yoelii was evaluated showed that the causal prophylactics act more specifically against the pre-erythrocytic than against the erythrocytic forms. This specificity was most pronounced among the DHFR-inhibitors, whose outstanding activity may be explained by the fact that the rate of multiplication of the pre-erythrocytic forms of P. b. yoelii is greater than that of other plasmodia used hitherto; it is also greater than the rate shown by the malaria parasites of man and that of the erythrocytic forms of P. b. yoelii itself. We believe that this feature will render P. b. yoelii very useful for determination of the causal prophylactic activity

  1. Economic consequences of high throughput maskless lithography

    NASA Astrophysics Data System (ADS)

    Hartley, John G.; Govindaraju, Lakshmi

    2005-11-01

    Many people in the semiconductor industry bemoan the high costs of masks and view mask cost as one of the significant barriers to bringing new chip designs to market. All that is needed is a viable maskless technology and the problem will go away. Numerous sites around the world are working on maskless lithography but inevitably, the question asked is "Wouldn't a one wafer per hour maskless tool make a really good mask writer?" Of course, the answer is yes, the hesitation you hear in the answer isn't based on technology concerns, it's financial. The industry needs maskless lithography because mask costs are too high. Mask costs are too high because mask pattern generators (PG's) are slow and expensive. If mask PG's become much faster, mask costs go down, the maskless market goes away and the PG supplier is faced with an even smaller tool demand from the mask shops. Technical success becomes financial suicide - or does it? In this paper we will present the results of a model that examines some of the consequences of introducing high throughput maskless pattern generation. Specific features in the model include tool throughput for masks and wafers, market segmentation by node for masks and wafers and mask cost as an entry barrier to new chip designs. How does the availability of low cost masks and maskless tools affect the industries tool makeup and what is the ultimate potential market for high throughput maskless pattern generators?

  2. High Throughput Optimization of Stem Cell Microenvironments

    PubMed Central

    Yang, Fan; Mei, Ying; Langer, Robert; Anderson, Daniel G.

    2009-01-01

    Stem cells have great potential as cell sources for regenerative medicine due to both their self-renewal and multi-lineage differentiation capacity. Despite advances in the field of stem cell biology, major challenges remain before stem cells can be widely used for therapeutic purposes. One challenge is to develop reproducible methods to control stem cell growth and differentiation. The niche in which stem cells reside is a complex, multi-factorial environment. In contrast to using cells alone, biomaterials can provide initial structural support, and allow cells to adhere, proliferate and differentiate in a three-dimensional environment. Researchers have incorporated signals into the biomaterials that can promote desired cell functions in a spatially and temporally controlled manner. Despite progress in biomaterial design and methods to modulate cellular behavior, many of the complex signal networks that regulate cell-material interactions remain unclear. Due to the vast numbers of material properties to be explored and the complexity of cell-surface interactions, it is often difficult to optimize stem cell microenvironments using conventional, iterative approaches. To address these challenges, high throughput screening of combinatorial libraries has emerged as a novel approach to achieve rapid screening with reduced materials and costs. In this review, we discuss recent research in the area of high throughput approaches for characterization and optimization of cellular interactions with their microenvironments. In contrast to conventional approaches, screening combinatorial libraries can result in the discovery of unexpected material solutions to these complex problems. PMID:19601753

  3. Preliminary High-Throughput Metagenome Assembly

    SciTech Connect

    Dusheyko, Serge; Furman, Craig; Pangilinan, Jasmyn; Shapiro, Harris; Tu, Hank

    2007-03-26

    Metagenome data sets present a qualitatively different assembly problem than traditional single-organism whole-genome shotgun (WGS) assembly. The unique aspects of such projects include the presence of a potentially large number of distinct organisms and their representation in the data set at widely different fractions. In addition, multiple closely related strains could be present, which would be difficult to assemble separately. Failure to take these issues into account can result in poor assemblies that either jumble together different strains or which fail to yield useful results. The DOE Joint Genome Institute has sequenced a number of metagenomic projects and plans to considerably increase this number in the coming year. As a result, the JGI has a need for high-throughput tools and techniques for handling metagenome projects. We present the techniques developed to handle metagenome assemblies in a high-throughput environment. This includes a streamlined assembly wrapper, based on the JGI?s in-house WGS assembler, Jazz. It also includes the selection of sensible defaults targeted for metagenome data sets, as well as quality control automation for cleaning up the raw results. While analysis is ongoing, we will discuss preliminary assessments of the quality of the assembly results (http://fames.jgi-psf.org).

  4. Plants as Sources of Antimalarial Drugs Part. 1. In vitro Test Method for the Evaluation of Crude Extracts from Plants.

    PubMed

    O'neill, M J; Bray, D H; Boardman, P; Phillipson, J D; Warhurst, D C

    1985-10-01

    An IN VITRO antimalarial test, utilising the inhibition of uptake of [G- (3)H]-hypoxanthine into PLASMODIUM FALCIPARUM cultured in human blood, has been used to assess the activity of crude extracts of ARTEMISIA ANNUA and A. VULGARIS (Compositae) and of BRUCEA JAVANICA, AILANTHUS ALTISSIMA, and SIMABA CEDRON (Simaroubaceae).

  5. Computational analysis of high-throughput flow cytometry data

    PubMed Central

    Robinson, J Paul; Rajwa, Bartek; Patsekin, Valery; Davisson, Vincent Jo

    2015-01-01

    Introduction Flow cytometry has been around for over 40 years, but only recently has the opportunity arisen to move into the high-throughput domain. The technology is now available and is highly competitive with imaging tools under the right conditions. Flow cytometry has, however, been a technology that has focused on its unique ability to study single cells and appropriate analytical tools are readily available to handle this traditional role of the technology. Areas covered Expansion of flow cytometry to a high-throughput (HT) and high-content technology requires both advances in hardware and analytical tools. The historical perspective of flow cytometry operation as well as how the field has changed and what the key changes have been discussed. The authors provide a background and compelling arguments for moving toward HT flow, where there are many innovative opportunities. With alternative approaches now available for flow cytometry, there will be a considerable number of new applications. These opportunities show strong capability for drug screening and functional studies with cells in suspension. Expert opinion There is no doubt that HT flow is a rich technology awaiting acceptance by the pharmaceutical community. It can provide a powerful phenotypic analytical toolset that has the capacity to change many current approaches to HT screening. The previous restrictions on the technology, based on its reduced capacity for sample throughput, are no longer a major issue. Overcoming this barrier has transformed a mature technology into one that can focus on systems biology questions not previously considered possible. PMID:22708834

  6. Markers of anti-malarial drug resistance in Plasmodium falciparum isolates from Swaziland: identification of pfmdr1-86F in natural parasite isolates

    PubMed Central

    2010-01-01

    Background The development of Plasmodium falciparum resistance to chloroquine (CQ) has limited its use in many malaria endemic areas of the world. However, despite recent drug policy changes to adopt the more effective artemisinin-based combination (ACT) in Africa and in the Southern African region, in 2007 Swaziland still relied on CQ as first-line anti-malarial drug. Methods Parasite DNA was amplified from P. falciparum isolates from Swaziland collected in 1999 (thick smear blood slides) and 2007 (filter paper blood spots). Markers of CQ and sulphadoxine-pyrimethamine (SP) resistance were identified by probe-based qPCR and DNA sequencing. Results Retrospective microscopy, confirmed by PCR amplification, found that only six of 252 patients treated for uncomplicated malaria in 2007 carried detectable P. falciparum. The pfcrt haplotype 72C/73V/74I/75E/76T occurred at a prevalence of 70% (n = 64) in 1999 and 83% (n = 6) in 2007. Prevalence of the pfmdr1-86N allele was 24% in 1999 and 67% in 2007. A novel substitution of phenylalanine for asparagine at codon 86 of pfmdr1 (N86F) occurred in two of 51 isolates successfully amplified from 1999. The pfmdr1-1246Y allele was common in 1999, with a prevalence of 49%, but was absent among isolates collected in 2007. The 86N/184F/1246D pfmdr1 haplotype, associated with enhanced parasite survival in patients treated with artemether-lumefantrine, comprised 8% of 1999 isolates, and 67% among 2007 isolates. The pfdhfr triple-mutant 16C/51I/59R/108N/164I haplotype associated with pyrimethamine resistance was common in both 1999 (82%, n = 34) and 2007 (50%, n = 6), as was the wild-type 431I/436S/437A/540K/581A/613A haplotype of pfdhps (100% and 93% respectively in 1999 and 2007). The quintuple-mutant haplotype pfdhfr/pfdhps-CIRNI/ISGEAA, associated with high-level resistance to SP, was rare (9%) among 1999 isolates and absent among 2007 isolates. Conclusions The prevalence of pfcrt and pfmdr1 alleles reported in this study is

  7. High-Throughput Analysis of Enzyme Activities

    SciTech Connect

    Lu, Guoxin

    2007-01-01

    High-throughput screening (HTS) techniques have been applied to many research fields nowadays. Robot microarray printing technique and automation microtiter handling technique allows HTS performing in both heterogeneous and homogeneous formats, with minimal sample required for each assay element. In this dissertation, new HTS techniques for enzyme activity analysis were developed. First, patterns of immobilized enzyme on nylon screen were detected by multiplexed capillary system. The imaging resolution is limited by the outer diameter of the capillaries. In order to get finer images, capillaries with smaller outer diameters can be used to form the imaging probe. Application of capillary electrophoresis allows separation of the product from the substrate in the reaction mixture, so that the product doesn't have to have different optical properties with the substrate. UV absorption detection allows almost universal detection for organic molecules. Thus, no modifications of either the substrate or the product molecules are necessary. This technique has the potential to be used in screening of local distribution variations of specific bio-molecules in a tissue or in screening of multiple immobilized catalysts. Another high-throughput screening technique is developed by directly monitoring the light intensity of the immobilized-catalyst surface using a scientific charge-coupled device (CCD). Briefly, the surface of enzyme microarray is focused onto a scientific CCD using an objective lens. By carefully choosing the detection wavelength, generation of product on an enzyme spot can be seen by the CCD. Analyzing the light intensity change over time on an enzyme spot can give information of reaction rate. The same microarray can be used for many times. Thus, high-throughput kinetic studies of hundreds of catalytic reactions are made possible. At last, we studied the fluorescence emission spectra of ADP and obtained the detection limits for ADP under three different

  8. Research influence on antimalarial drug policy change in Tanzania: case study of replacing chloroquine with sulfadoxine-pyrimethamine as the first-line drug

    PubMed Central

    Mubyazi, Godfrey M; Gonzalez-Block, Miguel A

    2005-01-01

    Introduction Research is an essential tool in facing the challenges of scaling up interventions and improving access to services. As in many other countries, the translation of research evidence into drug policy action in Tanzania is often constrained by poor communication between researchers and policy decision-makers, individual perceptions or attitudes towards the drug and hesitation by some policy decision-makers to approve change when they anticipate possible undesirable repercussions should the policy change as proposed. Internationally, literature on the role of researchers on national antimalarial drug policy change is limited. Objectives To describe the (a) role of researchers in producing evidence that influenced the Tanzanian government replace chloroquine (CQ) with sulfadoxine-pyrimethamine (SP) as the first-line drug and the challenges faced in convincing policy-makers, general practitioners, pharmaceutical industry and the general public on the need for change (b) challenges ahead before a new drug combination treatment policy is introduced in Tanzania. Methods In-depth interviews were held with national-level policy-makers, malaria control programme managers, pharmaceutical officers, general medical practitioners, medical research library and publications officers, university academicians, heads of medical research institutions and district and regional medical officers. Additional data were obtained through a review of malaria drug policy documents and participant observations were also done. Results In year 2001, the Tanzanian Government officially changed its malaria treatment policy guidelines whereby CQ – the first-line drug for a long time was replaced with SP. This policy decision was supported by research evidence indicating parasite resistance to CQ and clinical CQ treatment failure rates to have reached intolerable levels as compared to SP and amodiaquine (AQ). Research also indicated that since SP was also facing rising resistance trend

  9. High Throughput Screening Tools for Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Wong-Ng, W.; Yan, Y.; Otani, M.; Martin, J.; Talley, K. R.; Barron, S.; Carroll, D. L.; Hewitt, C.; Joress, H.; Thomas, E. L.; Green, M. L.; Tang, X. F.

    2015-06-01

    A suite of complementary high-throughput screening systems for combinatorial films was developed at National Institute of Standards and Technology to facilitate the search for efficient thermoelectric materials. These custom-designed capabilities include a facility for combinatorial thin film synthesis and a suite of tools for screening the Seebeck coefficient, electrical resistance (electrical resistivity), and thermal effusivity (thermal conductivity) of these films. The Seebeck coefficient and resistance are measured via custom-built automated apparatus at both ambient and high temperatures. Thermal effusivity is measured using a frequency domain thermoreflectance technique. This paper will discuss applications using these tools on representative thermoelectric materials, including combinatorial composition-spread films, conventional films, single crystals, and ribbons.

  10. A high-throughput neutron spectrometer

    NASA Astrophysics Data System (ADS)

    Stampfl, Anton; Noakes, Terry; Bartsch, Friedl; Bertinshaw, Joel; Veliscek-Carolan, Jessica; Nateghi, Ebrahim; Raeside, Tyler; Yethiraj, Mohana; Danilkin, Sergey; Kearley, Gordon

    2010-03-01

    A cross-disciplinary high-throughput neutron spectrometer is currently under construction at OPAL, ANSTO's open pool light-water research reactor. The spectrometer is based on the design of a Be-filter spectrometer (FANS) that is operating at the National Institute of Standards research reactor in the USA. The ANSTO filter-spectrometer will be switched in and out with another neutron spectrometer, the triple-axis spectrometer, Taipan. Thus two distinct types of neutron spectrometers will be accessible: one specialised to perform phonon dispersion analysis and the other, the filter-spectrometer, designed specifically to measure vibrational density of states. A summary of the design will be given along with a detailed ray-tracing analysis. Some preliminary results will be presented from the spectrometer.

  11. High-Throughput Nonlinear Optical Microscopy

    PubMed Central

    So, Peter T.C.; Yew, Elijah Y.S.; Rowlands, Christopher

    2013-01-01

    High-resolution microscopy methods based on different nonlinear optical (NLO) contrast mechanisms are finding numerous applications in biology and medicine. While the basic implementations of these microscopy methods are relatively mature, an important direction of continuing technological innovation lies in improving the throughput of these systems. Throughput improvement is expected to be important for studying fast kinetic processes, for enabling clinical diagnosis and treatment, and for extending the field of image informatics. This review will provide an overview of the fundamental limitations on NLO microscopy throughput. We will further cover several important classes of high-throughput NLO microscope designs with discussions on their strengths and weaknesses and their key biomedical applications. Finally, this review will close with a perspective of potential future technological improvements in this field. PMID:24359736

  12. High-throughput cellular RNA device engineering.

    PubMed

    Townshend, Brent; Kennedy, Andrew B; Xiang, Joy S; Smolke, Christina D

    2015-10-01

    Methods for rapidly assessing sequence-structure-function landscapes and developing conditional gene-regulatory devices are critical to our ability to manipulate and interface with biology. We describe a framework for engineering RNA devices from preexisting aptamers that exhibit ligand-responsive ribozyme tertiary interactions. Our methodology utilizes cell sorting, high-throughput sequencing and statistical data analyses to enable parallel measurements of the activities of hundreds of thousands of sequences from RNA device libraries in the absence and presence of ligands. Our tertiary-interaction RNA devices performed better in terms of gene silencing, activation ratio and ligand sensitivity than optimized RNA devices that rely on secondary-structure changes. We applied our method to build biosensors for diverse ligands and determine consensus sequences that enable ligand-responsive tertiary interactions. These methods advance our ability to develop broadly applicable genetic tools and to elucidate the underlying sequence-structure-function relationships that empower rational design of complex biomolecules. PMID:26258292

  13. Microfluidics for cell-based high throughput screening platforms - A review.

    PubMed

    Du, Guansheng; Fang, Qun; den Toonder, Jaap M J

    2016-01-15

    In the last decades, the basic techniques of microfluidics for the study of cells such as cell culture, cell separation, and cell lysis, have been well developed. Based on cell handling techniques, microfluidics has been widely applied in the field of PCR (Polymerase Chain Reaction), immunoassays, organ-on-chip, stem cell research, and analysis and identification of circulating tumor cells. As a major step in drug discovery, high-throughput screening allows rapid analysis of thousands of chemical, biochemical, genetic or pharmacological tests in parallel. In this review, we summarize the application of microfluidics in cell-based high throughput screening. The screening methods mentioned in this paper include approaches using the perfusion flow mode, the droplet mode, and the microarray mode. We also discuss the future development of microfluidic based high throughput screening platform for drug discovery.

  14. Image-based high-throughput screening for inhibitors of angiogenesis.

    PubMed

    Evensen, Lasse; Link, Wolfgang; Lorens, James B

    2013-01-01

    Automated multicolor fluorescence microscopy facilitates high-throughput quantitation of cellular parameters of complex, organotypic systems. In vitro co-cultured vascular cells form capillary-like networks that model facets of angiogenesis, making it an attractive alternative for anti-angiogenic drug discovery. We have adapted this angiogenesis assay system to a high-throughput format to enable automated image-based high-throughput screening of live primary human vascular cell co-cultures with chemical libraries for anti-angiogenic drug discovery. Protocols are described for setup of a fluorescence-based co-culture assay, live cell image acquisition, image analysis of morphological parameters, and screening data handling. PMID:23027002

  15. Yeast-based High-Throughput Screen Identifies Plasmodium falciparum Equilibrative Nucleoside Transporter 1 Inhibitors That Kill Malaria Parasites

    PubMed Central

    Frame, I. J.; Deniskin, Roman; Rinderspacher, Alison; Katz, Francine; Deng, Shi-Xian; Moir, Robyn D.; Adjalley, Sophie H.; Coburn-Flynn, Olivia; Fidock, David A.; Willis, Ian M.; Landry, Donald W.; Akabas, Myles H.

    2015-01-01

    Equilibrative transporters are potential drug targets, however most functional assays involve radioactive substrate uptake that is unsuitable for high-throughput screens (HTS). We developed a robust yeast-based growth assay that is potentially applicable to many equilibrative transporters. As proof of principle, we applied our approach to Equilibrative Nucleoside Transporter 1 of the malarial parasite Plasmodium falciparum (PfENT1). PfENT1 inhibitors might serve as novel antimalarial drugs since PfENT1-mediated purine import is essential for parasite proliferation. To identify PfENT1 inhibitors, we screened 64,560 compounds and identified 171 by their ability to rescue the growth of PfENT1-expressing fui1Δ yeast in the presence of a cytotoxic PfENT1 substrate, 5-fluorouridine (5-FUrd). In secondary assays, nine of the highest activity compounds inhibited PfENT1-dependent growth of a purine auxotrophic yeast strain with adenosine as the sole purine source (IC50 0.2–2 µM). These nine compounds completely blocked [3H]adenosine uptake into PfENT1-expressing yeast and erythrocyte-free trophozoite-stage parasites (IC50 5–50 nM), and inhibited chloroquine-sensitive and -resistant parasite proliferation (IC50 5–50 µM). Wild-type (WT) parasite IC50 values were up to four-fold lower compared to PfENT1-knockout (pfent1Δ) parasites. pfent1Δ parasite killing showed a delayed-death phenotype not observed with WT. We infer that in parasites, the compounds inhibit both PfENT1 and a secondary target with similar efficacy. The secondary target identity is unknown, but its existence may reduce the likelihood of parasites developing resistance to PfENT1 inhibitors. Our data support the hypothesis that blocking purine transport through PfENT1 may be a novel and compelling approach for antimalarial drug development. PMID:25602169

  16. Induction of multiple pleiotropic drug resistance genes in yeast engineered to produce an increased level of anti-malarial drug precursor, artemisinic acid

    PubMed Central

    Ro, Dae-Kyun; Ouellet, Mario; Paradise, Eric M; Burd, Helcio; Eng, Diana; Paddon, Chris J; Newman, Jack D; Keasling, Jay D

    2008-01-01

    Background Due to the global occurrence of multi-drug-resistant malarial parasites (Plasmodium falciparum), the anti-malarial drug most effective against malaria is artemisinin, a natural product (sesquiterpene lactone endoperoxide) extracted from sweet wormwood (Artemisia annua). However, artemisinin is in short supply and unaffordable to most malaria patients. Artemisinin can be semi-synthesized from its precursor artemisinic acid, which can be synthesized from simple sugars using microorganisms genetically engineered with genes from A. annua. In order to develop an industrially competent yeast strain, detailed analyses of microbial physiology and development of gene expression strategies are required. Results Three plant genes coding for amorphadiene synthase, amorphadiene oxidase (AMO or CYP71AV1), and cytochrome P450 reductase, which in concert divert carbon flux from farnesyl diphosphate to artemisinic acid, were expressed from a single plasmid. The artemisinic acid production in the engineered yeast reached 250 μg mL-1 in shake-flask cultures and 1 g L-1 in bio-reactors with the use of Leu2d selection marker and appropriate medium formulation. When plasmid stability was measured, the yeast strain synthesizing amorphadiene alone maintained the plasmid in 84% of the cells, whereas the yeast strain synthesizing artemisinic acid showed poor plasmid stability. Inactivation of AMO by a point-mutation restored the high plasmid stability, indicating that the low plasmid stability is not caused by production of the AMO protein but by artemisinic acid synthesis or accumulation. Semi-quantitative reverse-transcriptase (RT)-PCR and quantitative real time-PCR consistently showed that pleiotropic drug resistance (PDR) genes, belonging to the family of ATP-Binding Cassette (ABC) transporter, were massively induced in the yeast strain producing artemisinic acid, relative to the yeast strain producing the hydrocarbon amorphadiene alone. Global transcriptional analysis by

  17. Development of a membrane impregnated with a poly(dimethylsiloxane)/poly(ethylene glycol) copolymer for a high-throughput screening of the permeability of drugs, cosmetics, and other chemicals across the human skin.

    PubMed

    Miki, Ryotaro; Ichitsuka, Yasuna; Yamada, Takumi; Kimura, Soichiro; Egawa, Yuya; Seki, Toshinobu; Juni, Kazuhiko; Ueda, Hideo; Morimoto, Yasunori

    2015-01-23

    We aimed to develop a high-throughput screening (HTS) system for preliminary predictions of human skin permeability by using an artificial membrane that can mimic the permeation behaviour of lipophilic and hydrophilic compounds across the human skin. In this study, we synthesized a copolymer containing poly(dimethylsiloxane) (PDMS) and poly(ethylene glycol) (PEG) 6000 and impregnated it onto a supportive membrane filter to prepare a PDMS/PEG 6000 copolymer-impregnated membrane. In addition, we synthesized another polymer without PEG units and used it to prepare an impregnated membrane for determining the role of PEG 6000 units in the PDMS/PEG 6000 copolymer-impregnated membrane. The permeation characteristics of the impregnated membranes were evaluated on the basis of the permeability coefficients of 12 model compounds with different lipophilicities, by using a 2-chamber diffusion cell, and these permeability coefficients were compared with those across the human skin. We obtained a good correlation between the permeability coefficients across the PDMS/PEG 6000 copolymer-impregnated membrane and human skin. Further, we evaluated the permeation characteristics of a 96-well plate model of the PDMS/PEG 6000 copolymer by using 6 model compounds. We obtained an ideal correlation between the permeability coefficients across the PDMS/PEG 6000 copolymer using a 96-well plate and those across the human skin. Thus, the PDMS/PEG 6000 copolymer would be a good candidate for preliminary evaluation of the permeability of lipophilic and hydrophilic compounds across the human skin.

  18. High-throughput measurements of the optical redox ratio using a commercial microplate reader

    NASA Astrophysics Data System (ADS)

    Cannon, Taylor M.; Shah, Amy T.; Walsh, Alex J.; Skala, Melissa C.

    2015-01-01

    There is a need for accurate, high-throughput, functional measures to gauge the efficacy of potential drugs in living cells. As an early marker of drug response in cells, cellular metabolism provides an attractive platform for high-throughput drug testing. Optical techniques can noninvasively monitor NADH and FAD, two autofluorescent metabolic coenzymes. The autofluorescent redox ratio, defined as the autofluorescence intensity of NADH divided by that of FAD, quantifies relative rates of cellular glycolysis and oxidative phosphorylation. However, current microscopy methods for redox ratio quantification are time-intensive and low-throughput, limiting their practicality in drug screening. Alternatively, high-throughput commercial microplate readers quickly measure fluorescence intensities for hundreds of wells. This study found that a commercial microplate reader can differentiate the receptor status of breast cancer cell lines (p<0.05) based on redox ratio measurements without extrinsic contrast agents. Furthermore, microplate reader redox ratio measurements resolve response (p<0.05) and lack of response (p>0.05) in cell lines that are responsive and nonresponsive, respectively, to the breast cancer drug trastuzumab. These studies indicate that the microplate readers can be used to measure the redox ratio in a high-throughput manner and are sensitive enough to detect differences in cellular metabolism that are consistent with microscopy results.

  19. Proteomics equipped with multiplexing toward ultra high throughput.

    PubMed

    Kim, Min-Sik

    2015-01-01

    MS-based quantitative proteomics is a powerful technology to study virtually almost all biological and clinical samples. Although it has been known to be a high-throughput method, an MS analysis of a higher number of samples remains to be challenging practically and economically. In this issue, the use of multiplexing strategy for quantitative analysis of proteomes and phosphoproteomes has been demonstrated by Paulo et al. (Proteomics 2015, 15, 462-473) to better understand in vivo effects of two small molecule inhibitors on a mouse model. Within the short period of drug treatment, it has been found that the protein alteration is minimal in three tissues tested, whereas the phosphorylation level was widely altered. PMID:25522341

  20. Quantitative High-Throughput Luciferase Screening in Identifying CAR Modulators.

    PubMed

    Lynch, Caitlin; Zhao, Jinghua; Wang, Hongbing; Xia, Menghang

    2016-01-01

    The constitutive androstane receptor (CAR, NR1I3) is responsible for the transcription of multiple drug metabolizing enzymes and transporters. There are two possible methods of activation for CAR, direct ligand binding and a ligand-independent method, which makes this a unique nuclear receptor. Both of these mechanisms require translocation of CAR from the cytoplasm into the nucleus. Interestingly, CAR is constitutively active in immortalized cell lines due to the basal nuclear location of this receptor. This creates an important challenge in most in vitro assay models because immortalized cells cannot be used without inhibiting the high basal activity. In this book chapter, we go into detail of how to perform quantitative high-throughput screens to identify hCAR1 modulators through the employment of a double stable cell line. Using this line, we are able to identify activators, as well as deactivators, of the challenging nuclear receptor, CAR. PMID:27518621

  1. Antimalarial properties of orally active iron chelators.

    PubMed

    Heppner, D G; Hallaway, P E; Kontoghiorghes, G J; Eaton, J W

    1988-07-01

    The appearance of widespread multiple drug resistance in human malaria has intensified the search for new antimalarial compounds. Metal chelators, especially those with high affinity for iron, represent one presently unexploited class of antimalarials. Unfortunately the use of previously identified chelators as antimalarials has been precluded by their toxicity and, in the case of desferrioxamine, the necessity for parenteral administration. The investigators now report that a new class of orally active iron chelators, namely the derivatives of alpha-ketohydroxypyridines (KHPs), are potent antimalarials against cultured Plasmodium falciparum. The KHPs evidently exert this effect by sequestering iron because a preformed chelator:iron complex has no antimalarial action. The pool(s) of iron being sequestered by the chelators have not been identified but may not include serum transferrin. Preincubation of human serum with KHPs followed by removal of the drug results in the removal of greater than 97% of total serum iron. Nonetheless, this serum effectively supports the growth of P falciparum cultures. Therefore the KHPs may exert antimalarial effect through chelation of erythrocytic rather than serum iron pool(s). The investigators conclude that these powerful, orally active iron chelators may form the basis of a new class of antimalarial drugs. PMID:3291984

  2. Discovery of new antimalarial chemotypes through chemical methodology and library development.

    PubMed

    Brown, Lauren E; Chih-Chien Cheng, Ken; Wei, Wan-Guo; Yuan, Pingwei; Dai, Peng; Trilles, Richard; Ni, Feng; Yuan, Jing; MacArthur, Ryan; Guha, Rajarshi; Johnson, Ronald L; Su, Xin-zhuan; Dominguez, Melissa M; Snyder, John K; Beeler, Aaron B; Schaus, Scott E; Inglese, James; Porco, John A

    2011-04-26

    In an effort to expand the stereochemical and structural complexity of chemical libraries used in drug discovery, the Center for Chemical Methodology and Library Development at Boston University has established an infrastructure to translate methodologies accessing diverse chemotypes into arrayed libraries for biological evaluation. In a collaborative effort, the NIH Chemical Genomics Center determined IC(50)'s for Plasmodium falciparum viability for each of 2,070 members of the CMLD-BU compound collection using quantitative high-throughput screening across five parasite lines of distinct geographic origin. Three compound classes displaying either differential or comprehensive antimalarial activity across the lines were identified, and the nascent structure activity relationships (SAR) from this experiment used to initiate optimization of these chemotypes for further development.

  3. The anti-malarial atovaquone increases radiosensitivity by alleviating tumour hypoxia.

    PubMed

    Ashton, Thomas M; Fokas, Emmanouil; Kunz-Schughart, Leoni A; Folkes, Lisa K; Anbalagan, Selvakumar; Huether, Melanie; Kelly, Catherine J; Pirovano, Giacomo; Buffa, Francesca M; Hammond, Ester M; Stratford, Michael; Muschel, Ruth J; Higgins, Geoff S; McKenna, William Gillies

    2016-01-01

    Tumour hypoxia renders cancer cells resistant to cancer therapy, resulting in markedly worse clinical outcomes. To find clinical candidate compounds that reduce hypoxia in tumours, we conduct a high-throughput screen for oxygen consumption rate (OCR) reduction and identify a number of drugs with this property. For this study we focus on the anti-malarial, atovaquone. Atovaquone rapidly decreases the OCR by more than 80% in a wide range of cancer cell lines at pharmacological concentrations. In addition, atovaquone eradicates hypoxia in FaDu, HCT116 and H1299 spheroids. Similarly, it reduces hypoxia in FaDu and HCT116 xenografts in nude mice, and causes a significant tumour growth delay when combined with radiation. Atovaquone is a ubiquinone analogue, and decreases the OCR by inhibiting mitochondrial complex III. We are now undertaking clinical studies to assess whether atovaquone reduces tumour hypoxia in patients, thereby increasing the efficacy of radiotherapy. PMID:27453292

  4. The anti-malarial atovaquone increases radiosensitivity by alleviating tumour hypoxia

    PubMed Central

    Ashton, Thomas M.; Fokas, Emmanouil; Kunz-Schughart, Leoni A.; Folkes, Lisa K.; Anbalagan, Selvakumar; Huether, Melanie; Kelly, Catherine J.; Pirovano, Giacomo; Buffa, Francesca M.; Hammond, Ester M.; Stratford, Michael; Muschel, Ruth J.; Higgins, Geoff S.; McKenna, William Gillies

    2016-01-01

    Tumour hypoxia renders cancer cells resistant to cancer therapy, resulting in markedly worse clinical outcomes. To find clinical candidate compounds that reduce hypoxia in tumours, we conduct a high-throughput screen for oxygen consumption rate (OCR) reduction and identify a number of drugs with this property. For this study we focus on the anti-malarial, atovaquone. Atovaquone rapidly decreases the OCR by more than 80% in a wide range of cancer cell lines at pharmacological concentrations. In addition, atovaquone eradicates hypoxia in FaDu, HCT116 and H1299 spheroids. Similarly, it reduces hypoxia in FaDu and HCT116 xenografts in nude mice, and causes a significant tumour growth delay when combined with radiation. Atovaquone is a ubiquinone analogue, and decreases the OCR by inhibiting mitochondrial complex III. We are now undertaking clinical studies to assess whether atovaquone reduces tumour hypoxia in patients, thereby increasing the efficacy of radiotherapy. PMID:27453292

  5. Data Analysis for High-Throughput RNAi Screening.

    PubMed

    Azorsa, David O; Turnidge, Megan A; Arora, Shilpi

    2016-01-01

    High-throughput RNA interference (HT-RNAi) screening is an effective technology to help identify important genes and pathways involved in a biological process. Analysis of high-throughput RNAi screening data is a critical part of this technology, and many analysis methods have been described. Here, we summarize the workflow and types of analyses commonly used in high-throughput RNAi screening. PMID:27581298

  6. High Throughput Screening and Selection Methods for Directed Enzyme Evolution

    PubMed Central

    2015-01-01

    Successful evolutionary enzyme engineering requires a high throughput screening or selection method, which considerably increases the chance of obtaining desired properties and reduces the time and cost. In this review, a series of high throughput screening and selection methods are illustrated with significant and recent examples. These high throughput strategies are also discussed with an emphasis on compatibility with phenotypic analysis during directed enzyme evolution. Lastly, certain limitations of current methods, as well as future developments, are briefly summarized. PMID:26074668

  7. Comparative protein modeling of 1-deoxy-D-xylulose-5-phosphate reductoisomerase enzyme from Plasmodium falciparum: a potential target for antimalarial drug discovery.

    PubMed

    Singh, Nidhi; Chevé, Gwénaël; Avery, Mitchell A; McCurdy, Christopher R

    2006-01-01

    Plasmodium falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase (Pf-DXR) is a potential target for antimalarial chemotherapy. The three-dimensional model (3D) of this enzyme was determined by means of comparative modeling through multiple alignment followed by intensive optimization, minimization, and validation. The resulting model demonstrates a reasonable topology as gauged from the Ramachandran plot and acceptable three-dimensional structure compatibility as assessed by the Profiles-3D score. The modeled monomeric subunit consists of three domains: (1) N-terminal NADPH binding domain, (2) connective or linker domain (with most of the active site residues located in this domain), and (3) a C-terminal domain. This structure proved to be consistent with known DXR crystal structures from other species. The predicted active site compared favorably with those of the templates and appears to have an active site with a highly conserved architecture. Additionally, the model explains several site-directed mutagenesis data. Besides using several protein structure-checking programs to validate the model, a set of known inhibitors of DXR were also docked into the active site of the modeled Pf-DXR. The docked scores correlated reasonably well with experimental pIC50 values with a regression coefficient (R2) equal to 0.84. Results of the current study should prove useful in the early design and development of inhibitors by either de novo drug design or virtual screening of large small-molecule databases leading to development of new antimalarial agents. PMID:16711755

  8. High School Students Are a Target Group for Fight against Self-Medication with Antimalarial Drugs: A Pilot Study in University of Kinshasa, Democratic Republic of Congo

    PubMed Central

    Kabongo Kamitalu, Ramsès; Aloni, Michel Ntetani

    2016-01-01

    Aim. To assess the self-medication against malaria infection in population of Congolese students in Kinshasa, Democratic Republic of Congo (DRC). Methods. A cross-sectional study was carried out in University of Kinshasa, Kinshasa, Democratic Republic of Congo. Medical records of all students with malaria admitted to Centre de Santé Universitaire of University of Kinshasa from January 1, 2008, to April 30, 2008, were reviewed retrospectively. Results. The median age of the patients was 25.4 years (range: from 18 to 36 years). The majority of them were male (67.9%). Artemisinin-based combination treatments (ACTs) was the most used self-prescribed antimalarial drugs. However, self-medication was associated with the ingestion of quinine in 19.9% of cases. No case of ingestion of artesunate/artemether in monotherapy was found. All the medicines taken were registered in DRC. In this series, self-prescribed antimalarial was very irrational in terms of dose and duration of treatment. Conclusion. This paper highlights self-medication by a group who should be aware of malaria treatment protocols. The level of self-prescribing quinine is relatively high among students and is disturbing for a molecule reserved for severe disease in Congolese health care policy in management of malaria. PMID:27340411

  9. High-throughput approaches to understanding gene function and mapping network architecture in bacteria.

    PubMed

    Brochado, Ana Rita; Typas, Athanasios

    2013-04-01

    Advances in sequencing technology have provided an unprecedented view of bacterial diversity, along with a daunting number of novel genes. Within this new reality lies the challenge of developing large-scale approaches to assign function to the new genes and place them in pathways. Here, we highlight recent advances on this front, focusing on how high-throughput gene-gene, gene-drug and drug-drug interactions can yield functional and mechanistic inferences in bacteria. PMID:23403119

  10. High throughput sample processing and automated scoring.

    PubMed

    Brunborg, Gunnar; Jackson, Petra; Shaposhnikov, Sergey; Dahl, Hildegunn; Azqueta, Amaya; Collins, Andrew R; Gutzkow, Kristine B

    2014-01-01

    The comet assay is a sensitive and versatile method for assessing DNA damage in cells. In the traditional version of the assay, there are many manual steps involved and few samples can be treated in one experiment. High throughput (HT) modifications have been developed during recent years, and they are reviewed and discussed. These modifications include accelerated scoring of comets; other important elements that have been studied and adapted to HT are cultivation and manipulation of cells or tissues before and after exposure, and freezing of treated samples until comet analysis and scoring. HT methods save time and money but they are useful also for other reasons: large-scale experiments may be performed which are otherwise not practicable (e.g., analysis of many organs from exposed animals, and human biomonitoring studies), and automation gives more uniform sample treatment and less dependence on operator performance. The HT modifications now available vary largely in their versatility, capacity, complexity, and costs. The bottleneck for further increase of throughput appears to be the scoring. PMID:25389434

  11. High-Throughput Enzyme Kinetics Using Microarrays

    SciTech Connect

    Guoxin Lu; Edward S. Yeung

    2007-11-01

    We report a microanalytical method to study enzyme kinetics. The technique involves immobilizing horseradish peroxidase on a poly-L-lysine (PLL)- coated glass slide in a microarray format, followed by applying substrate solution onto the enzyme microarray. Enzyme molecules are immobilized on the PLL-coated glass slide through electrostatic interactions, and no further modification of the enzyme or glass slide is needed. In situ detection of the products generated on the enzyme spots is made possible by monitoring the light intensity of each spot using a scientific-grade charged-coupled device (CCD). Reactions of substrate solutions of various types and concentrations can be carried out sequentially on one enzyme microarray. To account for the loss of enzyme from washing in between runs, a standard substrate solution is used for calibration. Substantially reduced amounts of substrate solution are consumed for each reaction on each enzyme spot. The Michaelis constant K{sub m} obtained by using this method is comparable to the result for homogeneous solutions. Absorbance detection allows universal monitoring, and no chemical modification of the substrate is needed. High-throughput studies of native enzyme kinetics for multiple enzymes are therefore possible in a simple, rapid, and low-cost manner.

  12. Orthogonal NGS for High Throughput Clinical Diagnostics.

    PubMed

    Chennagiri, Niru; White, Eric J; Frieden, Alexander; Lopez, Edgardo; Lieber, Daniel S; Nikiforov, Anastasia; Ross, Tristen; Batorsky, Rebecca; Hansen, Sherry; Lip, Va; Luquette, Lovelace J; Mauceli, Evan; Margulies, David; Milos, Patrice M; Napolitano, Nichole; Nizzari, Marcia M; Yu, Timothy; Thompson, John F

    2016-04-19

    Next generation sequencing is a transformative technology for discovering and diagnosing genetic disorders. However, high-throughput sequencing remains error-prone, necessitating variant confirmation in order to meet the exacting demands of clinical diagnostic sequencing. To address this, we devised an orthogonal, dual platform approach employing complementary target capture and sequencing chemistries to improve speed and accuracy of variant calls at a genomic scale. We combined DNA selection by bait-based hybridization followed by Illumina NextSeq reversible terminator sequencing with DNA selection by amplification followed by Ion Proton semiconductor sequencing. This approach yields genomic scale orthogonal confirmation of ~95% of exome variants. Overall variant sensitivity improves as each method covers thousands of coding exons missed by the other. We conclude that orthogonal NGS offers improvements in variant calling sensitivity when two platforms are used, better specificity for variants identified on both platforms, and greatly reduces the time and expense of Sanger follow-up, thus enabling physicians to act on genomic results more quickly.

  13. High-throughput rod-induced electrospinning

    NASA Astrophysics Data System (ADS)

    Wu, Dezhi; Xiao, Zhiming; Teh, Kwok Siong; Han, Zhibin; Luo, Guoxi; Shi, Chuan; Sun, Daoheng; Zhao, Jinbao; Lin, Liwei

    2016-09-01

    A high throughput electrospinning process, directly from flat polymer solution surfaces induced by a moving insulating rod, has been proposed and demonstrated. Different rods made of either phenolic resin or paper with a diameter of 1–3 cm and a resistance of about 100–500 MΩ, has been successfully utilized in the process. The rod is placed approximately 10 mm above the flat polymer solution surface with a moving speed of 0.005–0.4 m s‑1 this causes the solution to generate multiple liquid jets under an applied voltage of 15–60 kV for the tip-less electrospinning process. The local electric field induced by the rod can boost electrohydrodynamic instability in order to generate Taylor cones and liquid jets. Experimentally, it is found that a large rod diameter and a small solution-to-rod distance can enhance the local electrical field to reduce the magnitude of the applied voltage. In the prototype setup with poly (ethylene oxide) polymer solution, an area of 5 cm  ×  10 cm and under an applied voltage of 60 kV, the maximum throughput of nanofibers is recorded to be approximately144 g m‑2 h‑1.

  14. Orthogonal NGS for High Throughput Clinical Diagnostics

    PubMed Central

    Chennagiri, Niru; White, Eric J.; Frieden, Alexander; Lopez, Edgardo; Lieber, Daniel S.; Nikiforov, Anastasia; Ross, Tristen; Batorsky, Rebecca; Hansen, Sherry; Lip, Va; Luquette, Lovelace J.; Mauceli, Evan; Margulies, David; Milos, Patrice M.; Napolitano, Nichole; Nizzari, Marcia M.; Yu, Timothy; Thompson, John F.

    2016-01-01

    Next generation sequencing is a transformative technology for discovering and diagnosing genetic disorders. However, high-throughput sequencing remains error-prone, necessitating variant confirmation in order to meet the exacting demands of clinical diagnostic sequencing. To address this, we devised an orthogonal, dual platform approach employing complementary target capture and sequencing chemistries to improve speed and accuracy of variant calls at a genomic scale. We combined DNA selection by bait-based hybridization followed by Illumina NextSeq reversible terminator sequencing with DNA selection by amplification followed by Ion Proton semiconductor sequencing. This approach yields genomic scale orthogonal confirmation of ~95% of exome variants. Overall variant sensitivity improves as each method covers thousands of coding exons missed by the other. We conclude that orthogonal NGS offers improvements in variant calling sensitivity when two platforms are used, better specificity for variants identified on both platforms, and greatly reduces the time and expense of Sanger follow-up, thus enabling physicians to act on genomic results more quickly. PMID:27090146

  15. High-throughput rod-induced electrospinning

    NASA Astrophysics Data System (ADS)

    Wu, Dezhi; Xiao, Zhiming; Teh, Kwok Siong; Han, Zhibin; Luo, Guoxi; Shi, Chuan; Sun, Daoheng; Zhao, Jinbao; Lin, Liwei

    2016-09-01

    A high throughput electrospinning process, directly from flat polymer solution surfaces induced by a moving insulating rod, has been proposed and demonstrated. Different rods made of either phenolic resin or paper with a diameter of 1-3 cm and a resistance of about 100-500 MΩ, has been successfully utilized in the process. The rod is placed approximately 10 mm above the flat polymer solution surface with a moving speed of 0.005-0.4 m s-1 this causes the solution to generate multiple liquid jets under an applied voltage of 15-60 kV for the tip-less electrospinning process. The local electric field induced by the rod can boost electrohydrodynamic instability in order to generate Taylor cones and liquid jets. Experimentally, it is found that a large rod diameter and a small solution-to-rod distance can enhance the local electrical field to reduce the magnitude of the applied voltage. In the prototype setup with poly (ethylene oxide) polymer solution, an area of 5 cm  ×  10 cm and under an applied voltage of 60 kV, the maximum throughput of nanofibers is recorded to be approximately144 g m-2 h-1.

  16. Deciphering the genomic targets of alkylating polyamide conjugates using high-throughput sequencing

    PubMed Central

    Chandran, Anandhakumar; Syed, Junetha; Taylor, Rhys D.; Kashiwazaki, Gengo; Sato, Shinsuke; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

    2016-01-01

    Chemically engineered small molecules targeting specific genomic sequences play an important role in drug development research. Pyrrole-imidazole polyamides (PIPs) are a group of molecules that can bind to the DNA minor-groove and can be engineered to target specific sequences. Their biological effects rely primarily on their selective DNA binding. However, the binding mechanism of PIPs at the chromatinized genome level is poorly understood. Herein, we report a method using high-throughput sequencing to identify the DNA-alkylating sites of PIP-indole-seco-CBI conjugates. High-throughput sequencing analysis of conjugate 2 showed highly similar DNA-alkylating sites on synthetic oligos (histone-free DNA) and on human genomes (chromatinized DNA context). To our knowledge, this is the first report identifying alkylation sites across genomic DNA by alkylating PIP conjugates using high-throughput sequencing. PMID:27098039

  17. Absence of Association between Polymorphisms in the RING E3 Ubiquitin Protein Ligase Gene and Ex Vivo Susceptibility to Conventional Antimalarial Drugs in Plasmodium falciparum Isolates from Dakar, Senegal.

    PubMed

    Gendrot, Mathieu; Fall, Bécaye; Madamet, Marylin; Fall, Mansour; Wade, Khalifa Ababacar; Amalvict, Rémy; Nakoulima, Aminata; Benoit, Nicolas; Diawara, Silman; Diémé, Yaya; Diatta, Bakary; Wade, Boubacar; Pradines, Bruno

    2016-08-01

    The RING E3 ubiquitin protein ligase is crucial for facilitating the transfer of ubiquitin. The only polymorphism identified in the E3 ubiquitin protein ligase gene was the D113N mutation (62.5%) but was not significantly associated with the 50% inhibitory concentration (IC50) of conventional antimalarial drugs. However, some mutated isolates (D113N) present a trend of reduced susceptibility to piperaquine (P = 0.0938). To evaluate the association of D113N polymorphism with susceptibility to antimalarials, more isolates are necessary. PMID:27185795

  18. A robust robotic high-throughput antibody purification platform.

    PubMed

    Schmidt, Peter M; Abdo, Michael; Butcher, Rebecca E; Yap, Min-Yin; Scotney, Pierre D; Ramunno, Melanie L; Martin-Roussety, Genevieve; Owczarek, Catherine; Hardy, Matthew P; Chen, Chao-Guang; Fabri, Louis J

    2016-07-15

    Monoclonal antibodies (mAbs) have become the fastest growing segment in the drug market with annual sales of more than 40 billion US$ in 2013. The selection of lead candidate molecules involves the generation of large repertoires of antibodies from which to choose a final therapeutic candidate. Improvements in the ability to rapidly produce and purify many antibodies in sufficient quantities reduces the lead time for selection which ultimately impacts on the speed with which an antibody may transition through the research stage and into product development. Miniaturization and automation of chromatography using micro columns (RoboColumns(®) from Atoll GmbH) coupled to an automated liquid handling instrument (ALH; Freedom EVO(®) from Tecan) has been a successful approach to establish high throughput process development platforms. Recent advances in transient gene expression (TGE) using the high-titre Expi293F™ system have enabled recombinant mAb titres of greater than 500mg/L. These relatively high protein titres reduce the volume required to generate several milligrams of individual antibodies for initial biochemical and biological downstream assays, making TGE in the Expi293F™ system ideally suited to high throughput chromatography on an ALH. The present publication describes a novel platform for purifying Expi293F™-expressed recombinant mAbs directly from cell-free culture supernatant on a Perkin Elmer JANUS-VariSpan ALH equipped with a plate shuttle device. The purification platform allows automated 2-step purification (Protein A-desalting/size exclusion chromatography) of several hundred mAbs per week. The new robotic method can purify mAbs with high recovery (>90%) at sub-milligram level with yields of up to 2mg from 4mL of cell-free culture supernatant.

  19. Fluorescent Approaches to High Throughput Crystallography

    NASA Technical Reports Server (NTRS)

    Pusey, Marc L.; Forsythe, Elizabeth; Achari, Aniruddha

    2006-01-01

    We have shown that by covalently modifying a subpopulation, less than or equal to 1%, of a macromolecule with a fluorescent probe, the labeled material will add to a growing crystal as a microheterogeneous growth unit. Labeling procedures can be readily incorporated into the final stages of purification, and the presence of the probe at low concentrations does not affect the X-ray data quality or the crystallization behavior. The presence of the trace fluorescent label gives a number of advantages when used with high throughput crystallizations. The covalently attached probe will concentrate in the crystal relative to the solution, and under fluorescent illumination crystals show up as bright objects against a dark background. Non-protein structures, such as salt crystals, will not incorporate the probe and will not show up under fluorescent illumination. Brightly fluorescent crystals are readily found against less bright precipitated phases, which under white light illumination may obscure the crystals. Automated image analysis to find crystals should be greatly facilitated, without having to first define crystallization drop boundaries as the protein or protein structures is all that shows up. Fluorescence intensity is a faster search parameter, whether visually or by automated methods, than looking for crystalline features. We are now testing the use of high fluorescence intensity regions, in the absence of clear crystalline features or "hits", as a means for determining potential lead conditions. A working hypothesis is that kinetics leading to non-structured phases may overwhelm and trap more slowly formed ordered assemblies, which subsequently show up as regions of brighter fluorescence intensity. Preliminary experiments with test proteins have resulted in the extraction of a number of crystallization conditions from screening outcomes based solely on the presence of bright fluorescent regions. Subsequent experiments will test this approach using a wider

  20. Use of bacterial surrogates as a tool to explore antimalarial drug interaction: Synergism between inhibitors of malarial dihydrofolate reductase and dihydropteroate synthase.

    PubMed

    Talawanich, Yuwadee; Kamchonwongpaisan, Sumalee; Sirawaraporn, Worachart; Yuthavong, Yongyuth

    2015-09-01

    Interaction between antimalarial drugs is important in determining the outcome of chemotherapy using drug combinations. Inhibitors of dihydrofolate reductase (DHFR) such as pyrimethamine and of dihydropteroate synthase (DHPS) such as sulfa drugs are known to have synergistic interactions. However, studies of the synergism are complicated by the fact that the malaria parasite can also salvage exogenous folates, and the salvage may also be affected by the drugs. It is desirable to have a convenient system to study interaction of DHFR and DHPS inhibitors without such complications. Here, we describe the use of Escherichia coli transformed with malarial DHFR and DHPS, while its own corresponding genes have been inactivated by optimal concentration of trimethoprim and genetic knockout, respectively, to study the interaction of the inhibitors. Marked synergistic effects are observed for all combinations of pyrimethamine and sulfa inhibitors in the presence of trimethoprim. At 0.05μM trimethoprim, sum of fractional inhibitory concentrations, ΣFIC of pyrimethamine with sulfadoxine, pyrimethamine with sulfathiazole, pyrimethamine with sulfamethoxazole, and pyrimethamine with dapsone are in the range of 0.24-0.41. These results show synergism between inhibitors of the two enzymes even in the absence of folate transport and uptake. This bacterial surrogate system should be useful as a tool for assessing the interactions of drug combinations between the DHFR and DHPS inhibitors.

  1. High-Throughput Baculovirus Expression System for Membrane Protein Production.

    PubMed

    Kalathur, Ravi C; Panganiban, Marinela; Bruni, Renato

    2016-01-01

    The ease of use, robustness, cost-effectiveness, and posttranslational machinery make baculovirus expression system a popular choice for production of eukaryotic membrane proteins. This system can be readily adapted for high-throughput operations. This chapter outlines the techniques and procedures for cloning, transfection, small-scale production, and purification of membrane protein samples in a high-throughput manner. PMID:27485337

  2. In vitro evaluation of the cytotoxic and genotoxic effects of artemether, an antimalarial drug, in a gastric cancer cell line (PG100).

    PubMed

    Alcântara, Diego Di Felipe Ávila; Ribeiro, Helem Ferreira; Cardoso, Plínio Cerqueira Dos Santos; Araújo, Taíssa Maíra Thomaz; Burbano, Rommel Rodriguez; Guimarães, Adriana Costa; Khayat, André Salim; de Oliveira Bahia, Marcelo

    2013-02-01

    Artemisinin is a sesquiterpene lactone endoperoxide, obtained from Artemisia annua, and extensively used as an antimalarial drug. Many studies have reported the genotoxic and cytotoxic effects of artemisinins; however, there are no studies that compare such effects between cancer cell lines and normal human cells after treatment with artemether, an artemisinin derivative. Gastric cancer is the fourth most frequent type of cancer and the second highest cause of cancer mortality worldwide. Thus, the aim of this study was to evaluate the in vitro genotoxic and cytotoxic effects induced by artemether in gastric cancer cell line (PG100) and compare them with the results obtained in human lymphocytes exposed to the same conditions. We used MTT (3-(4,5-methylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide) assay, comet assay and ethidium bromide/acridine orange viability staining to evaluate the cytotoxic and genotoxic effects of artemether in PG100. MTT assay showed a decrease in the survival percentages for both cell types treated with different concentrations of artemether (P < 0.05). PG100 also showed a significant dose-dependent increase in DNA damage index at concentrations of 119.4 and 238.8 µg ml(-1) (P < 0.05). Our results showed that artemether induced necrosis in PG100 at concentrations of 238.8 and 477.6 µg ml(-1), for all the tested harvest times (P < 0.05). In lymphocytes, artemether induced both apoptosis and necrosis at concentrations of 238.8 and 477.6 µg ml(-1), for all the tested harvest times (P < 0.05). In conclusion, human lymphocytes were more sensitive to the cytotoxic effects of the antimalarial drug than the gastric cancer cell line PG100. PMID:21953315

  3. Traditionally-used antimalarials from the Meliaceae.

    PubMed

    Omar, S; Zhang, J; MacKinnon, S; Leaman, D; Durst, T; Philogene, B J R; Arnason, J T; Sanchez-Vindas, P E; Poveda, L; Tamez, P A; Pezzuto, J M

    2003-01-01

    A quantitative ethnobotanical approach to antimalarial drug discovery led to the identification of Lansium domesticum Corr. Ser. (Meliaceae) as an important antimalarial used by Kenyah Dyak healers in Indonesian Borneo. Triterpenoid lansiolides with antimalarial activity were isolated from the bark and shown to have activity in both in vitro bioassays with Plasmodium falciparum, and in mice infected with P. berghei. A survey of African and tropical American Meliaceae led to further development of the limonoid gedunin from the traditionally used medicinal plants, tropical cedar, Cedrela odorata L., and neem, Azadirachta indica A. Juss. Gedunin has significant in vitro activity but initially showed poor in vivo activity. In vivo activity was improved by (1) incorporation into an easy to absorb suspension, (2) preparation of a more stable compound, 7-methoxygedunin; and (3) synergism with dillapiol, a cytochrome P450 3A4 inhibitor. The results show the potential for both antimalarial drug and phytomedicine development from traditionally used plants. PMID:12570769

  4. Life in the fast lane: high-throughput chemistry for lead generation and optimisation.

    PubMed

    Hunter, D

    2001-01-01

    The pharmaceutical industry has come under increasing pressure due to regulatory restrictions on the marketing and pricing of drugs, competition, and the escalating costs of developing new drugs. These forces can be addressed by the identification of novel targets, reductions in the development time of new drugs, and increased productivity. Emphasis has been placed on identifying and validating new targets and on lead generation: the response from industry has been very evident in genomics and high throughput screening, where new technologies have been applied, usually coupled with a high degree of automation. The combination of numerous new potential biological targets and the ability to screen large numbers of compounds against many of these targets has generated the need for large diverse compound collections. To address this requirement, high-throughput chemistry has become an integral part of the drug discovery process.

  5. Microfluidic-Enabled Print-to-Screen Platform for High-Throughput Screening of Combinatorial Chemotherapy.

    PubMed

    Ding, Yuzhe; Li, Jiannan; Xiao, Wenwu; Xiao, Kai; Lee, Joyce; Bhardwaj, Urvashi; Zhu, Zijie; Digiglio, Philip; Yang, Gaomai; Lam, Kit S; Pan, Tingrui

    2015-10-20

    Since the 1960s, combination chemotherapy has been widely utilized as a standard method to treat cancer. However, because of the potentially enormous number of drug candidates and combinations, conventional identification methods of the effective drug combinations are usually associated with significantly high operational costs, low throughput screening, laborious and time-consuming procedures, and ethical concerns. In this paper, we present a low-cost, high-efficiency microfluidic print-to-screen (P2S) platform, which integrates combinatorial screening with biomolecular printing for high-throughput screening of anticancer drug combinations. This P2S platform provides several distinct advantages and features, including automatic combinatorial printing, high-throughput parallel drug screening, modular disposable cartridge, and biocompatibility, which can potentially speed up the entire discovery cycle of potent drug combinations. Microfluidic impact printing utilizing plug-and-play microfluidic cartridges is experimentally characterized with controllable droplet volume and accurate positioning. Furthermore, the combinatorial print-to-screen assay is demonstrated in a proof-of-concept biological experiment which can identify the positive hits among the entire drug combination library in a parallel and rapid manner. Overall, this microfluidic print-to-screen platform offers a simple, low-cost, high-efficiency solution for high-throughput large-scale combinatorial screening and can be applicable for various emerging applications in drug cocktail discovery. PMID:26334956

  6. Virtual high throughput screening in new lead identification.

    PubMed

    Badrinarayan, Preethi; Sastry, G Narahari

    2011-12-01

    Drug discovery continues to be one of the greatest contemporary challenges and rational application of modelling approaches is the first important step to obtain lead compounds, which can be optimised further. Virtual high throughput screening (VHTS) is one of the efficient approaches to obtain lead structures for a given target. Strategic application of different screening filters like pharmacophore mapping, shape-based, ligand-based, molecular similarity etc., in combination with other drug design protocols provide invaluable insights in lead identification and optimization. Screening of large databases using these computational methods provides potential lead compounds, thus triggering a meaningful interplay between computations and experiments. In this review, we present a critical account on the relevance of molecular modelling approaches in general, lead optimization and virtual screening methods in particular for new lead identification. The importance of developing reliable scoring functions for non-bonded interactions has been highlighted, as it is an extremely important measure for the reliability of scoring function. The lead optimization and new lead design has also been illustrated with examples. The importance of employing a combination of general and target specific screening protocols has also been highlighted. PMID:21843146

  7. Multiplexing a high-throughput liability assay to leverage efficiencies.

    PubMed

    Herbst, John; Anthony, Monique; Stewart, Jeremy; Connors, David; Chen, Taosheng; Banks, Martyn; Petrillo, Edward W; Agler, Michele

    2009-06-01

    In order to identify potential cytochrome P-450 3A4 (drug-metabolizing enzyme) inducers at an early stage of the drug discovery process, a cell-based transactivation high-throughput luciferase reporter assay for the human pregnane X receptor (PXR) in HepG2 cells has been implemented and multiplexed with a viability end point for data interpretation, as part of a Lead Profiling portfolio of assays. As a routine part of Lead Profiling operations, assays are periodically evaluated for utility as well as for potential improvements in technology or process. We used a recent evaluation of our PXR-transactivation assay as a model for the application of Lean Thinking-based process analysis to lab-bench assay optimization and automation. This resulted in the development of a 384-well multiplexed homogeneous assay simultaneously detecting PXR transactivation and HepG2 cell cytotoxicity. In order to multiplex fluorescent and luminescent read-outs, modifications to each assay were necessary, which included optimization of multiple assay parameters such as cell density, plate type, and reagent concentrations. Subsequently, a set of compounds including known cytotoxic compounds and PXR inducers were used to validate the multiplexed assay. Results from the multiplexed assay correlate well with those from the singleplexed assay formats measuring PXR transactivation and viability separately. Implementation of the multiplexed assay for routine compound profiling provides improved data quality, sample conservation, cost savings, and resource efficiencies.

  8. High throughput LSPR and SERS analysis of aminoglycoside antibiotics.

    PubMed

    McKeating, Kristy S; Couture, Maxime; Dinel, Marie-Pier; Garneau-Tsodikova, Sylvie; Masson, Jean-Francois

    2016-08-15

    Aminoglycoside antibiotics are used in the treatment of infections caused by Gram-negative bacteria, and are often dispensed only in severe cases due to their adverse side effects. Patients undergoing treatment with these antibiotics are therefore commonly subjected to therapeutic drug monitoring (TDM) to ensure a safe and effective personalised dosage. The ability to detect these antibiotics in a rapid and sensitive manner in human fluids is therefore of the utmost importance in order to provide effective monitoring of these drugs, which could potentially allow for a more widespread use of this class of antibiotics. Herein, we report on the detection of various aminoglycosides, by exploiting their ability to aggregate gold nanoparticles. The number and position of the amino groups of aminoglycoside antibiotics controlled the aggregation process. We investigated the complementary techniques of surface enhanced Raman spectroscopy (SERS) and localized surface plasmon resonance (LSPR) for dual detection of these aminoglycoside antibiotics and performed an in-depth study of the feasibility of carrying out TDM of tobramycin using a platform amenable to high throughput analysis. Herein, we also demonstrate dual detection of tobramycin using both LSPR and SERS in a single platform and within the clinically relevant concentration range needed for TDM of this particular aminoglycoside. Additionally we provide evidence that tobramycin can be detected in spiked human serum using only functionalised nanoparticles and SERS analysis. PMID:27412506

  9. A High-Throughput Yeast Halo Assay for Bioactive Compounds.

    PubMed

    Bray, Walter; Lokey, R Scott

    2016-01-01

    When a disk of filter paper is impregnated with a cytotoxic or cytostatic drug and added to solid medium seeded with yeast, a visible clear zone forms around the disk whose size depends on the concentration and potency of the drug. This is the traditional "halo" assay and provides a convenient, if low-throughput, read-out of biological activity that has been the mainstay of antifungal and antibiotic testing for decades. Here, we describe a protocol for a high-throughput version of the halo assay, which uses an array of 384 pins to deliver ∼200 nL of stock solutions from compound plates onto single-well plates seeded with yeast. Using a plate reader in the absorbance mode, the resulting halos can be quantified and the data archived in the form of flat files that can be connected to compound databases with standard software. This assay has the convenience associated with the visual readout of the traditional halo assay but uses far less material and can be automated to screen thousands of compounds per day. PMID:27587777

  10. A Recombinant Human Pluripotent Stem Cell Line Stably Expressing Halide-Sensitive YFP-I152L for GABAAR and GlyR-Targeted High-Throughput Drug Screening and Toxicity Testing.

    PubMed

    Kuenzel, Katharina; Friedrich, Oliver; Gilbert, Daniel F

    2016-01-01

    GABAARs and GlyRs are considered attractive drug targets for therapeutic intervention and are also increasingly recognized in the context of in vitro neurotoxicity (NT) and developmental neurotoxicity (DNT) testing. However, systematic human-specific GABAAR and GlyR-targeted drug screening and toxicity testing is hampered due to lack of appropriate in vitro models that express native GABAARs and GlyRs. We have established a human pluripotent stem cell line (NT2) stably expressing YFP-I152L, a halide-sensitive variant of yellow fluorescent protein (YFP), allowing for fluorescence-based functional analysis of chloride channels. Upon stimulation with retinoic acid, NT2 cells undergo neuronal differentiation and allow pharmacological and toxicological evaluation of native GABAARs and GlyRs at different stages of brain maturation. We applied the cell line in concentration-response experiments with the neurotransmitters GABA and glycine as well as with the drugs strychnine, picrotoxin, fipronil, lindane, bicuculline, and zinc and demonstrate that the established in vitro model is applicable to GABAAR and GlyR-targeted pharmacological and toxicological profiling. We quantified the proportion of GABAAR and GlyR-sensitive cells, respectively, and identified percentages of approximately 20% each within the overall populations, rendering the cells a suitable model for systematic in vitro GABAAR and GlyR-targeted screening in the context of drug development and NT/DNT testing. PMID:27445687

  11. Molecular analysis of plasmid encoded multi-drug resistance (MDR) in Salmonella enterica animal isolates by PFGE, replicon typing, and DNA microarray screening followed by high-throughput DNA sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The development of Multi-Drug Resistant (MDR) Salmonella is of global concern. MDR Salmonella genes can be transmitted in a number of ways including transfer of plasmids. To understand how MDR plasmids develop and are transmitted, their genetics must be thoroughly described. To achieve t...

  12. A Recombinant Human Pluripotent Stem Cell Line Stably Expressing Halide-Sensitive YFP-I152L for GABAAR and GlyR-Targeted High-Throughput Drug Screening and Toxicity Testing

    PubMed Central

    Kuenzel, Katharina; Friedrich, Oliver; Gilbert, Daniel F.

    2016-01-01

    GABAARs and GlyRs are considered attractive drug targets for therapeutic intervention and are also increasingly recognized in the context of in vitro neurotoxicity (NT) and developmental neurotoxicity (DNT) testing. However, systematic human-specific GABAAR and GlyR-targeted drug screening and toxicity testing is hampered due to lack of appropriate in vitro models that express native GABAARs and GlyRs. We have established a human pluripotent stem cell line (NT2) stably expressing YFP-I152L, a halide-sensitive variant of yellow fluorescent protein (YFP), allowing for fluorescence-based functional analysis of chloride channels. Upon stimulation with retinoic acid, NT2 cells undergo neuronal differentiation and allow pharmacological and toxicological evaluation of native GABAARs and GlyRs at different stages of brain maturation. We applied the cell line in concentration-response experiments with the neurotransmitters GABA and glycine as well as with the drugs strychnine, picrotoxin, fipronil, lindane, bicuculline, and zinc and demonstrate that the established in vitro model is applicable to GABAAR and GlyR-targeted pharmacological and toxicological profiling. We quantified the proportion of GABAAR and GlyR-sensitive cells, respectively, and identified percentages of approximately 20% each within the overall populations, rendering the cells a suitable model for systematic in vitro GABAAR and GlyR-targeted screening in the context of drug development and NT/DNT testing. PMID:27445687

  13. Antimalarials in dermatology: mechanism of action, indications, and side effects.

    PubMed

    Rodriguez-Caruncho, C; Bielsa Marsol, I

    2014-04-01

    Antimalarial drugs have been in common use in dermatology since the 1950s. Their mechanism of action is complex, and it is now known that they act through various pathways. We review the indications for antimalarials in dermatology, their adverse effects, and some less well-known effects, such as their antithrombotic and hypolipidemic action. The most recent recommendations concerning ophthalmological screening in patients on antimalarials are also reviewed.

  14. Acridine and Acridinones: Old and New Structures with Antimalarial Activity

    PubMed Central

    Valdés, Aymé Fernández-Calienes

    2011-01-01

    Since emergence of chloroquine-resistant Plasmodium falciparum and reports of parasite resistance to alternative drugs, there has been renewed interest in the antimalarial activity of acridines and their congeners, the acridinones. This article presents literature compilation of natural acridinone alkaloids and synthetic 9-substituted acridines, acridinediones, haloalcoxyacridinones and 10-N-substituted acridinones with antimalarial activity. The review also provides an outlook to antimalarial modes of action of some described compounds. PMID:21673977

  15. Quinoline-based antimalarial hybrid compounds.

    PubMed

    Vandekerckhove, Stéphanie; D'hooghe, Matthias

    2015-08-15

    Quinoline-containing compounds, such as quinine and chloroquine, have a long-standing history as potent antimalarial agents. However, the increasing resistance of the Plasmodium parasite against these drugs and the lack of licensed malaria vaccines have forced chemists to develop synthetic strategies toward novel biologically active molecules. A strategy that has attracted considerable attention in current medicinal chemistry is based on the conjugation of two biologically active molecules into one hybrid compound. Since quinolines are considered to be privileged antimalarial building blocks, the synthesis of quinoline-containing antimalarial hybrids has been elaborated extensively in recent years. This review provides a literature overview of antimalarial hybrid molecules containing a quinoline core, covering publications between 2009 and 2014. PMID:25593097

  16. A high-throughput-compatible assay to measure the degradation of endogenous Huntingtin proteins

    PubMed Central

    Wu, Peng; Lu, Ming-xing; Cui, Xiao-tian; Yang, He-qing; Yu, Shen-liang; Zhu, Jian-bin; Sun, Xiao-li; Lu, Boxun

    2016-01-01

    Aim: The accumulation of disease-causing proteins is a common hallmark of many neurodegenerative disorders. Measuring the degradation of such proteins using high-throughput-compatible assays is highly desired for the identification of genetic and chemical modulators of degradation. For example, Huntington's disease (HD) is an incurable hereditary neurodegenerative disorder caused by the cytotoxicity of mutant huntingtin protein (mHTT). The high-throughput measurement of mHTT degradation is important in HD drug discovery and research. Existing methods for such purposes have limitations due to their dependence on protein tags or pan protein synthesis inhibitors. Here, we report a high-throughput-compatible pulse-chase method (CH-chase) for the measurement of endogenous tag-free huntingtin protein (HTT) degradation based on Click chemistry and Homogeneous Time Resolved Fluorescence (HTRF) technologies. Methods: The pulsed-labeled proteins were conjugated with biotin using the click reaction strain-promoted alkyne-azide cycloaddition (SPAAC), and the chase signals were calculated by measuring the reduction percentage of the HTT HTRF signals after pull-down with streptavidin beads. Results: We validated that the signals were within the linear detection range and were HTT-specific. We successfully measured the degradation of endogenous HTT in a high-throughput-compatible format using 96-well plates. The predicted changes of HTT degradation by known modifiers were observed, which confirmed that the assay is suitable for the identification of HTT degradation modifiers. Conclusion: We have established the first high-throughput-compatible assay capable of measuring endogenous, tag-free HTT degradation, providing a valuable tool for HD research and drug discovery. The method could be applied to other proteins and can facilitate research on other neurodegenerative disorders and proteinopathies. PMID:27264314

  17. Optical microplates for photonic high throughput screening of algal photosynthesis and biofuel production.

    PubMed

    Mertiri, Taulant; Chen, Meng; Holland, Thomas; Basu, Amar S

    2011-01-01

    Biological systems respond not only to chemical stimuli (drugs, proteins) but also to physical stimuli (light, heat, stress). Though there are many high throughput tools for screening chemical stimuli, no such tool exists for screening of physical stimuli. This paper presents a novel instrument for photonic high throughput screening of photosynthesis, a light-driven bioprocess. The optical microplate has a footprint identical to a standard 96 well plate, and it provides temporal and intensity control of light in each individual well. Intensity control provides 128 dimming levels (7-bit resolution), with maximum intensity 120 mE/cm(2). Temporal modulation, used for studying dynamics and regulation of photosynthesis, can be as low as 10 μs. We used photonic screening for high throughput studies of algal growth rates and photosynthetic efficiency, using the model organism Dunaliella tertiolecta, a lipid producing algae of interest in biofuel production. Due to the ability to conduct 96 studies in parallel, experiments that would require 2 years using conventional tools can be completed in 1 week. This instrument opens up novel high throughput protocols for photobiology and the growing field of phenomics.

  18. High-Throughput Sequencing in Mitochondrial DNA Research

    PubMed Central

    Ye, Fei; Samuels, David C.; Clark, Travis; Guo, Yan

    2014-01-01

    Next-generation sequencing, also known as high-throughput sequencing, has greatly enhanced researchers’ ability to conduct biomedical research on all levels. Mitochondrial research has also benefitted greatly from high-throughput sequencing; sequencing technology now allows for screening of all 16569 base pairs of the mitochondrial genome simultaneously for SNPs and low level heteroplasmy and, in some cases, the estimation of mitochondrial DNA copy number. It is important to realize the full potential of high-throughput sequencing for the advancement of mitochondrial research. To this end, we review how high-throughput sequencing has impacted mitochondrial research in the categories of SNPs, low level heteroplasmy, copy number, and structural variants. We also discuss the different types of mitochondrial DNA sequencing and their pros and cons. Based on previous studies conducted by various groups, we provide strategies for processing mitochondrial DNA sequencing data, including assembly, variant calling, and quality control. PMID:24859348

  19. High-Throughput Pharmacokinetics for Environmental Chemicals (SOT)

    EPA Science Inventory

    High throughput screening (HTS) promises to allow prioritization of thousands of environmental chemicals with little or no in vivo information. For bioactivity identified by HTS, toxicokinetic (TK) models are essential to predict exposure thresholds below which no significant bio...

  20. High-throughput sequencing in mitochondrial DNA research.

    PubMed

    Ye, Fei; Samuels, David C; Clark, Travis; Guo, Yan

    2014-07-01

    Next-generation sequencing, also known as high-throughput sequencing, has greatly enhanced researchers' ability to conduct biomedical research on all levels. Mitochondrial research has also benefitted greatly from high-throughput sequencing; sequencing technology now allows for screening of all 16,569 base pairs of the mitochondrial genome simultaneously for SNPs and low level heteroplasmy and, in some cases, the estimation of mitochondrial DNA copy number. It is important to realize the full potential of high-throughput sequencing for the advancement of mitochondrial research. To this end, we review how high-throughput sequencing has impacted mitochondrial research in the categories of SNPs, low level heteroplasmy, copy number, and structural variants. We also discuss the different types of mitochondrial DNA sequencing and their pros and cons. Based on previous studies conducted by various groups, we provide strategies for processing mitochondrial DNA sequencing data, including assembly, variant calling, and quality control.

  1. AOPs & Biomarkers: Bridging High Throughput Screening and Regulatory Decision Making.

    EPA Science Inventory

    As high throughput screening (HTS) approaches play a larger role in toxicity testing, computational toxicology has emerged as a critical component in interpreting the large volume of data produced. Computational models for this purpose are becoming increasingly more sophisticated...

  2. Development of A High Throughput Method Incorporating Traditional Analytical Devices

    PubMed Central

    White, C. C.; Embree, E.; Byrd, W. E; Patel, A. R.

    2004-01-01

    A high-throughput (high throughput is the ability to process large numbers of samples) and companion informatics system has been developed and implemented. High throughput is defined as the ability to autonomously evaluate large numbers of samples, while an informatics system provides the software control of the physical devices, in addition to the organization and storage of the generated electronic data. This high throughput system includes both an ultra-violet and visible light spectrometer (UV-Vis) and a Fourier transform infrared spectrometer (FTIR) integrated with a multi sample positioning table. This method is designed to quantify changes in polymeric materials occurring from controlled temperature, humidity and high flux UV exposures. The integration of the software control of these analytical instruments within a single computer system is presented. Challenges in enhancing the system to include additional analytical devices are discussed. PMID:27366626

  3. HIGH THROUGHPUT ASSESSMENTS OF CONVENTIONAL AND ALTERNATIVE COMPOUNDS

    EPA Science Inventory

    High throughput approaches for quantifying chemical hazard, exposure, and sustainability have the potential to dramatically impact the pace and nature of risk assessments. Integrated evaluation strategies developed at the US EPA incorporate inherency,bioactivity,bioavailability, ...

  4. High throughput growth and characterization of thin film materials

    NASA Astrophysics Data System (ADS)

    Mao, Samuel S.

    2013-09-01

    It usually takes more than 10 years for a new material from initial research to its first commercial application. Therefore, accelerating the pace of discovery of new materials is critical to tackling challenges in areas ranging from clean energy to national security. As discovery of new materials has not kept pace with the product design cycles in many sectors of industry, there is a pressing need to develop and utilize high throughput screening and discovery technologies for the growth and characterization of new materials. This article presents two distinctive types of high throughput thin film material growth approaches, along with a number of high throughput characterization techniques, established in the author's group. These approaches include a second-generation "discrete" combinatorial semiconductor discovery technology that enables the creation of arrays of individually separated thin film semiconductor materials of different compositions, and a "continuous" high throughput thin film material screening technology that enables the realization of ternary alloy libraries with continuously varying elemental ratios.

  5. Evaluating Rapid Models for High-Throughput Exposure Forecasting (SOT)

    EPA Science Inventory

    High throughput exposure screening models can provide quantitative predictions for thousands of chemicals; however these predictions must be systematically evaluated for predictive ability. Without the capability to make quantitative, albeit uncertain, forecasts of exposure, the ...

  6. High Throughput Profiling of Molecular Shapes in Crystals

    NASA Astrophysics Data System (ADS)

    Spackman, Peter R.; Thomas, Sajesh P.; Jayatilaka, Dylan

    2016-02-01

    Molecular shape is important in both crystallisation and supramolecular assembly, yet its role is not completely understood. We present a computationally efficient scheme to describe and classify the molecular shapes in crystals. The method involves rotation invariant description of Hirshfeld surfaces in terms of of spherical harmonic functions. Hirshfeld surfaces represent the boundaries of a molecule in the crystalline environment, and are widely used to visualise and interpret crystalline interactions. The spherical harmonic description of molecular shapes are compared and classified by means of principal component analysis and cluster analysis. When applied to a series of metals, the method results in a clear classification based on their lattice type. When applied to around 300 crystal structures comprising of series of substituted benzenes, naphthalenes and phenylbenzamide it shows the capacity to classify structures based on chemical scaffolds, chemical isosterism, and conformational similarity. The computational efficiency of the method is demonstrated with an application to over 14 thousand crystal structures. High throughput screening of molecular shapes and interaction surfaces in the Cambridge Structural Database (CSD) using this method has direct applications in drug discovery, supramolecular chemistry and materials design.

  7. High-throughput measurements of hydrogel tissue construct mechanics.

    PubMed

    Marquez, Juan Pablo; Legant, Wesley; Lam, Vy; Cayemberg, Amy; Elson, Elliot; Wakatsuki, Tetsuro

    2009-06-01

    Engineered tissues represent a natural environment for studying cell physiology, mechanics, and function. Cellular interactions with the extracellular matrix proteins are important determinants of cell physiology and tissue mechanics. Dysregulation of these parameters can result in diseases such as cardiac fibrosis and atherosclerosis. In this report we present a novel system to produce hydrogel tissue constructs (HTCs) and to characterize their mechanical properties. HTCs are grown in custom chambers and a robotic system is used to indent them and measure the resulting forces. Force measurements are then used to estimate HTC pretension (cellular contractility). Pretension was reduced in a dose-dependent manner by cytochalasin D (CD) treatment; the highest concentration (2microM) resulted in 10-fold decrease. On the other hand, treatment with fetal bovine serum (20%) resulted in approximately threefold increase in pretension. Excellent repeatability and precision were observed in measurements from replicate HTCs. The coefficient of statistical variance of quantified pretension ranged from 7% to 15% (n=4). Due to the small size (4x4x0.8mm) of the HTCs, this system of profiling HTC mechanics can readily be used in high-throughput applications. In particular, it can be used for screening chemical libraries in search of drugs that can alter tissue mechanics.

  8. High throughput virus plaque quantitation using a flatbed scanner.

    PubMed

    Sullivan, Kate; Kloess, Johannes; Qian, Chen; Bell, Donald; Hay, Alan; Lin, Yi Pu; Gu, Yan

    2012-01-01

    The plaque assay is a standard technique for measuring influenza virus infectivity and inhibition of virus replication. Counting plaque numbers and quantifying virus infection of cells in multiwell plates quickly, accurately and automatically remain a challenge. Visual inspection relies upon experience, is subjective, often time consuming, and has less reproducibility than automated methods. In this paper, a simple, high throughput imaging-based alternative is proposed which uses a flatbed scanner and image processing software to quantify the infected cell population and plaque formation. Quantitation results were evaluated with reference to visual counting and achieved better than 80% agreement. The method was shown to be particularly advantageous in titration of the number of plaques and infected cells when influenza viruses produce a heterogeneous population of small plaques. It was also shown to be insensitive to the densities of plaques in determination of neutralization titres and IC(50)s of drug susceptibility. In comparison to other available techniques, this approach is cost-effective, relatively accurate, and readily available.

  9. Comprehensive analysis of high-throughput screening data

    NASA Astrophysics Data System (ADS)

    Heyse, Stephan

    2002-06-01

    High-Throughput Screening (HTS) data in its entirety is a valuable raw material for the drug-discovery process. It provides the most compete information about the biological activity of a company's compounds. However, its quantity, complexity and heterogeneity require novel, sophisticated approaches in data analysis. At GeneData, we are developing methods for large-scale, synoptical mining of screening data in a five-step analysis: (1) Quality Assurance: Checking data for experimental artifacts and eliminating low quality data. (2) Biological Profiling: Clustering and ranking of compounds based on their biological activity, taking into account specific characteristics of HTS data. (3) Rule-based Classification: Applying user-defined rules to biological and chemical properties, and providing hypotheses on the biological mode-of-action of compounds. (4) Joint Biological-Chemical Analysis: Associating chemical compound data to HTS data, providing hypotheses for structure- activity relationships. (5) integration with Genomic and Gene Expression Data: Linking into other components of GeneData's bioinformatics platform, and assessing the compounds' modes-of-action, toxicity, and metabolic properties. These analyses address issues that are crucial for a correct interpretation and full exploitation of screening data. They lead to a sound rating of assays and compounds at an early state of the lead-finding process.

  10. Salmonella serotype determination utilizing high-throughput genome sequencing data.

    PubMed

    Zhang, Shaokang; Yin, Yanlong; Jones, Marcus B; Zhang, Zhenzhen; Deatherage Kaiser, Brooke L; Dinsmore, Blake A; Fitzgerald, Collette; Fields, Patricia I; Deng, Xiangyu

    2015-05-01

    Serotyping forms the basis of national and international surveillance networks for Salmonella, one of the most prevalent foodborne pathogens worldwide (1-3). Public health microbiology is currently being transformed by whole-genome sequencing (WGS), which opens the door to serotype determination using WGS data. SeqSero (www.denglab.info/SeqSero) is a novel Web-based tool for determining Salmonella serotypes using high-throughput genome sequencing data. SeqSero is based on curated databases of Salmonella serotype determinants (rfb gene cluster, fliC and fljB alleles) and is predicted to determine serotype rapidly and accurately for nearly the full spectrum of Salmonella serotypes (more than 2,300 serotypes), from both raw sequencing reads and genome assemblies. The performance of SeqSero was evaluated by testing (i) raw reads from genomes of 308 Salmonella isolates of known serotype; (ii) raw reads from genomes of 3,306 Salmonella isolates sequenced and made publicly available by GenomeTrakr, a U.S. national monitoring network operated by the Food and Drug Administration; and (iii) 354 other publicly available draft or complete Salmonella genomes. We also demonstrated Salmonella serotype determination from raw sequencing reads of fecal metagenomes from mice orally infected with this pathogen. SeqSero can help to maintain the well-established utility of Salmonella serotyping when integrated into a platform of WGS-based pathogen subtyping and characterization.

  11. High-throughput screening in academia: the Harvard experience.

    PubMed

    Stein, Ross L

    2003-12-01

    To identify small-molecule modulators of biologic systems, academic scientists are beginning to use high-throughput screening (HTS) approaches that have traditionally been used only in industry. The HTS laboratories that are being established in universities, while differing in details of staffing, equipment, and size, have all been created to attain 1 or more of 3 principal goals: drug discovery, chemical genetics, or training. This article will examine the role that these activities play in 4 HTS laboratories that have been created within the academic community of Harvard Medical School and its affiliated institutions. First, the 3 activities will be defined with special attention paid to describing the impact they are having on how academic biologic science is conducted today. Next, the histories and operations of the 4 Harvard laboratories are reviewed. In the course of these summaries, emphasis is placed on understanding the motivational role that the 3 activities initially played in the creation of the 4 Harvard facilities and the roles that the activities continue to play in their day-to-day operations. Finally, several concerns are identified that must be attended to for the successful establishment and operation of an academic biologic science that has yet to be fully determined. HTS has the ability to provide the tools to test previously untestable hypotheses and can thereby allow the discovery of the unanticipated and the truly novel.

  12. High Throughput Profiling of Molecular Shapes in Crystals

    PubMed Central

    Spackman, Peter R.; Thomas, Sajesh P.; Jayatilaka, Dylan

    2016-01-01

    Molecular shape is important in both crystallisation and supramolecular assembly, yet its role is not completely understood. We present a computationally efficient scheme to describe and classify the molecular shapes in crystals. The method involves rotation invariant description of Hirshfeld surfaces in terms of of spherical harmonic functions. Hirshfeld surfaces represent the boundaries of a molecule in the crystalline environment, and are widely used to visualise and interpret crystalline interactions. The spherical harmonic description of molecular shapes are compared and classified by means of principal component analysis and cluster analysis. When applied to a series of metals, the method results in a clear classification based on their lattice type. When applied to around 300 crystal structures comprising of series of substituted benzenes, naphthalenes and phenylbenzamide it shows the capacity to classify structures based on chemical scaffolds, chemical isosterism, and conformational similarity. The computational efficiency of the method is demonstrated with an application to over 14 thousand crystal structures. High throughput screening of molecular shapes and interaction surfaces in the Cambridge Structural Database (CSD) using this method has direct applications in drug discovery, supramolecular chemistry and materials design. PMID:26908351

  13. High Throughput Profiling of Molecular Shapes in Crystals.

    PubMed

    Spackman, Peter R; Thomas, Sajesh P; Jayatilaka, Dylan

    2016-01-01

    Molecular shape is important in both crystallisation and supramolecular assembly, yet its role is not completely understood. We present a computationally efficient scheme to describe and classify the molecular shapes in crystals. The method involves rotation invariant description of Hirshfeld surfaces in terms of of spherical harmonic functions. Hirshfeld surfaces represent the boundaries of a molecule in the crystalline environment, and are widely used to visualise and interpret crystalline interactions. The spherical harmonic description of molecular shapes are compared and classified by means of principal component analysis and cluster analysis. When applied to a series of metals, the method results in a clear classification based on their lattice type. When applied to around 300 crystal structures comprising of series of substituted benzenes, naphthalenes and phenylbenzamide it shows the capacity to classify structures based on chemical scaffolds, chemical isosterism, and conformational similarity. The computational efficiency of the method is demonstrated with an application to over 14 thousand crystal structures. High throughput screening of molecular shapes and interaction surfaces in the Cambridge Structural Database (CSD) using this method has direct applications in drug discovery, supramolecular chemistry and materials design. PMID:26908351

  14. High prevalence of pfdhfr-pfdhps triple mutations associated with anti-malarial drugs resistance in Plasmodium falciparum isolates seven years after the adoption of sulfadoxine-pyrimethamine in combination with artesunate as first-line treatment in Iran.

    PubMed

    Rouhani, Maryam; Zakeri, Sedigheh; Pirahmadi, Sakineh; Raeisi, Ahmad; Djadid, Navid Dinparast

    2015-04-01

    The spread of anti-malarial drug resistance will challenge any malaria control and elimination strategies, and routine monitoring of resistance-associated molecular markers of commonly used anti-malarial drugs is very important. Therefore, in the present investigation, the extent of mutations/haplotypes in dhfr and dhps genes of Plasmodium falciparum isolates (n=72) was analyzed seven years after the introduction of sulfadoxine-pyrimethamine (SP) plus artesunate (AS) as first-line anti-malarial treatment in Iran using PCR-RFLP methods. The results showed that the majority of the patients (97.2%) carried both 59R and 108N mutations in pure form with wild-type genotype at positions N51 and I164. Additionally, a significant increase (P<0.05) was observed in the frequency of R59N108/G437 haplotype (79.2%) during 2012-2014. This raise was because of the significant increase (P<0.05) in the frequency of 437G mutation (81.9%), which more likely was due to more availability of SP as anti-malarial drug for treatment of falciparum patients in these malaria-endemic areas of Iran. However, no quintuple mutations associated with treatment failure were detected. In conclusion, the present results along with in vivo assays suggest that seven years after the adoption of SP-AS as the first-line treatment in Iran, this drug remains efficacious for treatment of uncomplicated falciparum malaria, as a partner drug with AS in these malaria-endemic areas.

  15. Establishing an Infrastructure for High-Throughput Short-Interfering RNA Screening.

    PubMed

    Yin, Hongwei; Sereduk, Chris; Tang, Nanyun

    2016-01-01

    RNA interference (RNAi) is a readily available research tool that can be used to accelerate the identification and functional validation of a multitude of new candidate drug targets by experimentally perturbing gene expression and function. High-throughput RNAi technology using libraries of short-interfering RNA (siRNA) makes it possible to rapidly identify genes and biomarkers associated with biological processes such as diseases or a cellular response to therapy. Thus, RNAi-based screening is an extremely powerful technology that can provide tremendous insights into the mechanisms of action and contexts of vulnerability of a particular drug treatment. This chapter describes the infrastructure requirements needed to successfully perform HT-RNAi screening. Information on the methodology, instrumentation, experimental design, and workflow aspects is provided, as well as insights on how to successfully implement a high-throughput RNAi screen. PMID:27581280

  16. High Throughput Screening Identifies Novel Lead Compounds with Activity against Larval, Juvenile and Adult Schistosoma mansoni.

    PubMed

    Mansour, Nuha R; Paveley, Ross; Gardner, J Mark F; Bell, Andrew S; Parkinson, Tanya; Bickle, Quentin

    2016-04-01

    An estimated 600 million people are affected by the helminth disease schistosomiasis caused by parasites of the genus Schistosoma. There is currently only one drug recommended for treating schistosomiasis, praziquantel (PZQ), which is effective against adult worms but not against the juvenile stage. In an attempt to identify improved drugs for treating the disease, we have carried out high throughput screening of a number of small molecule libraries with the aim of identifying lead compounds with balanced activity against all life stages of Schistosoma. A total of almost 300,000 compounds were screened using a high throughput assay based on motility of worm larvae and image analysis of assay plates. Hits were screened against juvenile and adult worms to identify broadly active compounds and against a mammalian cell line to assess cytotoxicity. A number of compounds were identified as promising leads for further chemical optimization. PMID:27128493

  17. High Throughput Screening Identifies Novel Lead Compounds with Activity against Larval, Juvenile and Adult Schistosoma mansoni

    PubMed Central

    Gardner, J. Mark F.; Bell, Andrew S.; Parkinson, Tanya; Bickle, Quentin

    2016-01-01

    An estimated 600 million people are affected by the helminth disease schistosomiasis caused by parasites of the genus Schistosoma. There is currently only one drug recommended for treating schistosomiasis, praziquantel (PZQ), which is effective against adult worms but not against the juvenile stage. In an attempt to identify improved drugs for treating the disease, we have carried out high throughput screening of a number of small molecule libraries with the aim of identifying lead compounds with balanced activity against all life stages of Schistosoma. A total of almost 300,000 compounds were screened using a high throughput assay based on motility of worm larvae and image analysis of assay plates. Hits were screened against juvenile and adult worms to identify broadly active compounds and against a mammalian cell line to assess cytotoxicity. A number of compounds were identified as promising leads for further chemical optimization. PMID:27128493

  18. High Throughput Screening Identifies Novel Lead Compounds with Activity against Larval, Juvenile and Adult Schistosoma mansoni.

    PubMed

    Mansour, Nuha R; Paveley, Ross; Gardner, J Mark F; Bell, Andrew S; Parkinson, Tanya; Bickle, Quentin

    2016-04-01

    An estimated 600 million people are affected by the helminth disease schistosomiasis caused by parasites of the genus Schistosoma. There is currently only one drug recommended for treating schistosomiasis, praziquantel (PZQ), which is effective against adult worms but not against the juvenile stage. In an attempt to identify improved drugs for treating the disease, we have carried out high throughput screening of a number of small molecule libraries with the aim of identifying lead compounds with balanced activity against all life stages of Schistosoma. A total of almost 300,000 compounds were screened using a high throughput assay based on motility of worm larvae and image analysis of assay plates. Hits were screened against juvenile and adult worms to identify broadly active compounds and against a mammalian cell line to assess cytotoxicity. A number of compounds were identified as promising leads for further chemical optimization.

  19. SPIM-fluid: open source light-sheet based platform for high-throughput imaging.

    PubMed

    Gualda, Emilio J; Pereira, Hugo; Vale, Tiago; Estrada, Marta Falcão; Brito, Catarina; Moreno, Nuno

    2015-11-01

    Light sheet fluorescence microscopy has recently emerged as the technique of choice for obtaining high quality 3D images of whole organisms/embryos with low photodamage and fast acquisition rates. Here we present an open source unified implementation based on Arduino and Micromanager, which is capable of operating Light Sheet Microscopes for automatized 3D high-throughput imaging on three-dimensional cell cultures and model organisms like zebrafish, oriented to massive drug screening. PMID:26601007

  20. SPIM-fluid: open source light-sheet based platform for high-throughput imaging

    PubMed Central

    Gualda, Emilio J.; Pereira, Hugo; Vale, Tiago; Estrada, Marta Falcão; Brito, Catarina; Moreno, Nuno

    2015-01-01

    Light sheet fluorescence microscopy has recently emerged as the technique of choice for obtaining high quality 3D images of whole organisms/embryos with low photodamage and fast acquisition rates. Here we present an open source unified implementation based on Arduino and Micromanager, which is capable of operating Light Sheet Microscopes for automatized 3D high-throughput imaging on three-dimensional cell cultures and model organisms like zebrafish, oriented to massive drug screening. PMID:26601007

  1. Tyrosine kinase inhibitors: New class of antimalarials on the horizon?

    PubMed

    Pathak, Vrushali; Colah, Roshan; Ghosh, Kanjaksha

    2015-08-01

    Development of the antimalarial drug resistant strains has currently become a major public health challenge. There is an urgent need to develop new antimalarial drugs. Tyrosine kinase inhibitors (TKIs) are receiving increasing attention as anticancer therapy. It has revolutionarised the management of CML to say the least. TKIs are also increasingly being implicated in complicated but vital life cycle of malaria parasite. Hence we tested two commonly used but different classes of TKIs (imatinib and sorafenib) in-vitro for their antimalarial activity and possible synergistic activity with existing antimalarial drug. Antimalarial activity was tested with the help of modified WHO microtest technique in-vitro for five different Plasmodium falciparum laboratory strains (3D7, Dd2, 7G8, MRC2, PKL9). Imatinib and sorafenib showed a promising antimalarial activity with all the strains. These compounds caused dose dependent inhibition of parasite maturation. The isobologram analysis of the interactions of these TKIs with standard antimalarial drug, artesunate revealed distinct patterns of synergism, additivity and antagonism at different ratios. Imatinib showed worthwhile synergism with artesunate indicating imatinib and other tyrosine kinase inhibitors may have significant antimalarial activity and can be used in combination therapy. PMID:26142327

  2. Development of transgenic Artemisia annua (Chinese wormwood) plants with an enhanced content of artemisinin, an effective anti-malarial drug, by hairpin-RNA-mediated gene silencing.

    PubMed

    Zhang, Ling; Jing, Fuyuan; Li, Fupeng; Li, Meiya; Wang, Yuliang; Wang, Guofeng; Sun, Xiaofen; Tang, Kexuan

    2009-03-01

    Artemisinin is an effective anti-malarial drug isolated from Artemisia annua L. (Chinese wormwood), but the content of artemisinin in A. annua is low. In the present study we explored the possibility of using genetic engineering to increase the artemisinin content of A. annua by suppressing the expression of SQS (squalene synthase), a key enzyme of sterol pathway (a pathway competitive with that of artemisinin biosynthesis) by means of a hairpin-RNA-mediated RNAi (RNA interference) technique. A total of 23 independent transgenic A. annua plants were obtained through Agrobacterium tumefaciens-mediated transformation, which was confirmed by PCR and Southern-blot analyses. HPLC-evaporative light-scattering detection analysis showed that the artemisinin content of some transgenic plants was significantly increased, with the highest values reaching 31.4 mg/g dry weight, which is about 3.14-fold the content observed in untransformed control plants. Real-time reverse transcription-PCR analysis demonstrated that the expression of SQS was suppressed significantly, and GC-MS analysis showed that sterol was efficiently decreased in the transgenic plants. The present study demonstrated that genetic-engineering strategy of RNAi is an effective means of increasing artemisinin content in plants.

  3. Structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase in a quaternary complex with a magnesium ion, NADPH and the antimalarial drug fosmidomycin

    SciTech Connect

    Yajima, Shunsuke Hara, Kodai; Iino, Daisuke; Sasaki, Yasuyuki; Kuzuyama, Tomohisa; Ohsawa, Kanju; Seto, Haruo

    2007-06-01

    The crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) from Escherichia coli complexed with Mg{sup 2+}, NADPH and fosmidomycin was determined at 2.2 Å resolution. The structure showed a well defined loop conformation at the active site of DXR. The crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) from Escherichia coli complexed with Mg{sup 2+}, NADPH and fosmidomycin was solved at 2.2 Å resolution. DXR is the key enzyme in the 2-C-methyl-d-erythritol 4-phosphate pathway and is an effective target of antimalarial drugs such as fosmidomycin. In the crystal structure, electron density for the flexible loop covering the active site was clearly observed, indicating the well ordered conformation of DXR upon substrate binding. On the other hand, no electron density was observed for the nicotinamide-ribose portion of NADPH and the position of Asp149 anchoring Mg{sup 2+} was shifted by NADPH in the active site.

  4. Mining Chemical Activity Status from High-Throughput Screening Assays

    PubMed Central

    Soufan, Othman; Ba-alawi, Wail; Afeef, Moataz; Essack, Magbubah; Rodionov, Valentin; Kalnis, Panos; Bajic, Vladimir B.

    2015-01-01

    High-throughput screening (HTS) experiments provide a valuable resource that reports biological activity of numerous chemical compounds relative to their molecular targets. Building computational models that accurately predict such activity status (active vs. inactive) in specific assays is a challenging task given the large volume of data and frequently small proportion of active compounds relative to the inactive ones. We developed a method, DRAMOTE, to predict activity status of chemical compounds in HTP activity assays. For a class of HTP assays, our method achieves considerably better results than the current state-of-the-art-solutions. We achieved this by modification of a minority oversampling technique. To demonstrate that DRAMOTE is performing better than the other methods, we performed a comprehensive comparison analysis with several other methods and evaluated them on data from 11 PubChem assays through 1,350 experiments that involved approximately 500,000 interactions between chemicals and their target proteins. As an example of potential use, we applied DRAMOTE to develop robust models for predicting FDA approved drugs that have high probability to interact with the thyroid stimulating hormone receptor (TSHR) in humans. Our findings are further partially and indirectly supported by 3D docking results and literature information. The results based on approximately 500,000 interactions suggest that DRAMOTE has performed the best and that it can be used for developing robust virtual screening models. The datasets and implementation of all solutions are available as a MATLAB toolbox online at www.cbrc.kaust.edu.sa/dramote and can be found on Figshare. PMID:26658480

  5. Liquid gradient in two-dimensional matrix for high throughput screening.

    PubMed

    Hu, Shan-Wen; Xu, Bi-Yi; Xu, Jing-Juan; Chen, Hong-Yuan

    2013-01-01

    Based on the ingenious combination of two different gradient generation mechanisms, this work reports a novel approach for a high throughput linear liquid gradient in a two-dimensional (2D) matrix. Specifically, a typical Christmas Tree structure with two inlets was designed as the first mixture gradient generator, upon which the second diffusion gradient generator was coupled to produce the desired concentration series on the basis of the distance difference. Rather than a simple 1D line, the integration of the two generators would result in an innovative 2D matrix of reservoirs, which was then characterized both theoretically and experimentally. Theoretically, calculation of fluid field demonstrated the formation of a concentration gradient, which was then confirmed by the dye solution visualization analysis. For high throughput screening application, doxorubicin (Dox) was then selected as model medicine to treat the acute myeloblastic leukemia (HL-60) cells. Cell viability displayed that cell death rate enhanced with the increase of drug concentration, and this result was higher than that on a 96-well plate, and the corresponding mechanism was properly discussed. Subsequently, Dox and quercetin were employed simultaneously to generate an overlapping gradient and its effect on HL-60 cells was investigated. Due to the automatic formation of concentration gradient that could improve the work efficiency, this work provides a promising tool for future high throughput drug screening.

  6. Molecular classification of fatty liver by high-throughput profiling of protein post-translational modifications.

    PubMed

    Urasaki, Yasuyo; Fiscus, Ronald R; Le, Thuc T

    2016-04-01

    We describe an alternative approach to classifying fatty liver by profiling protein post-translational modifications (PTMs) with high-throughput capillary isoelectric focusing (cIEF) immunoassays. Four strains of mice were studied, with fatty livers induced by different causes, such as ageing, genetic mutation, acute drug usage, and high-fat diet. Nutrient-sensitive PTMs of a panel of 12 liver metabolic and signalling proteins were simultaneously evaluated with cIEF immunoassays, using nanograms of total cellular protein per assay. Changes to liver protein acetylation, phosphorylation, and O-N-acetylglucosamine glycosylation were quantified and compared between normal and diseased states. Fatty liver tissues could be distinguished from one another by distinctive protein PTM profiles. Fatty liver is currently classified by morphological assessment of lipid droplets, without identifying the underlying molecular causes. In contrast, high-throughput profiling of protein PTMs has the potential to provide molecular classification of fatty liver.

  7. Post-high-throughput screening analysis: an empirical compound prioritization scheme.

    PubMed

    Oprea, Tudor I; Bologa, Cristian G; Edwards, Bruce S; Prossnitz, Eric R; Sklar, Larry A

    2005-08-01

    An empirical scheme to evaluate and prioritize screening hits from high-throughput screening (HTS) is proposed. Negative scores are given when chemotypes found in the HTS hits are present in annotated databases such as MDDR and WOMBAT or for testing positive in toxicity-related experiments reported in TOXNET. Positive scores were given for higher measured biological activities, for testing negative in toxicity-related literature, and for good overlap when profiled against drug-related properties. Particular emphasis is placed on estimating aqueous solubility to prioritize in vivo experiments. This empirical scheme is given as an illustration to assist the decision-making process in selecting chemotypes and individual compounds for further experimentation, when confronted with multiple hits from high-throughput experiments. The decision-making process is discussed for a set of G-protein coupled receptor antagonists and validated on a literature example for dihydrofolate reductase inhibition.

  8. High-throughput approaches for evaluating absorption, distribution, metabolism and excretion properties of lead compounds.

    PubMed

    Tarbit, M H; Berman, J

    1998-06-01

    Combinatorial chemistry methods and high-throughput screening for leads in industrial drug discovery have generated a potential bottleneck in the optimisation processes that seek to align potency with good pharmacokinetics in order to produce good medicines. This has resulted in the need for higher throughput methods of screening for absorption, distribution, metabolism and excretion properties. Significant progress has been made in throughput of in vivo pharmacokinetic studies, with the introduction of cassette, or multiple-in-one, protocols. In this technique, typically up to ten compounds are administered in one dose and analysed concomitantly on the mass spectrometer. High-throughput methods in in vitro absorption, distribution, metabolism and excretion are less well-developed as yet, and current approaches comprise automation of well-established methods for absorption using cell lines and metabolism using liver microsomes.

  9. High-Throughput Quantification of Bioactive Lipids by MALDI Mass Spectrometry: Application to Prostaglandins

    PubMed Central

    Manna, Joseph D.; Reyzer, Michelle L.; Latham, Joey C.; Weaver, C. David; Marnett, Lawrence J.; Caprioli, Richard M.

    2011-01-01

    Analysis and quantification of analytes in biological systems is a critical component of metabolomic investigations of cell function. The most widely used methods employ chromatographic separation followed by mass spectrometric analysis, which requires significant time for sample preparation and sequential chromatography. We introduce a novel high-throughput, separation-free methodology based on MALDI mass spectrometry that allows for the parallel analysis of targeted metabolomes. Proof-of-concept is demonstrated by analysis of prostaglandins and glyceryl prostaglandins. Derivatization to incorporate a charged moiety into ketone-containing prostaglandins dramatically increases the signal-to-noise ratio relative to underivatized samples. This resulted in an increased dynamic range (15 fmol – 2000 fmol on plate) and improved linearity (r2= 0.99). The method was adapted for high-throughput screening methods for enzymology and drug discovery. Application to cellular metabolomics was also demonstrated. PMID:21770391

  10. Inkjet printing for high-throughput cell patterning.

    PubMed

    Roth, E A; Xu, T; Das, M; Gregory, C; Hickman, J J; Boland, T

    2004-08-01

    The adaptation of inkjet printing technology to the complex fields of tissue engineering and biomaterial development presents the potential to increase progress in these emerging technologies through the implementation of this high-throughput capability via automated processes to enable precise control and repeatability. In this paper, a method of applying high-throughput inkjet printing to control cellular attachment and proliferation by precise, automated deposition of collagen is presented. The results indicate that commercial inkjet printing technology can be used to create viable cellular patterns with a resolution of 350 microm through the deposition of biologically active proteins. This method demonstrates a combination of off-the-shelf inkjet printing and biomaterials and has potential to be adapted to tissue engineering and colony patterning applications. Adapting this method into the three-dimensional construction of cellular structures for eventual high-throughput tissue engineering using a bottom-up approach is possible.

  11. Combinatorial and high-throughput screening approaches for strain engineering.

    PubMed

    Liu, Wenshan; Jiang, Rongrong

    2015-03-01

    Microbes have long been used in the industry to produce valuable biochemicals. Combinatorial engineering approaches, new strain engineering tools derived from inverse metabolic engineering, have started to attract attention in recent years, including genome shuffling, error-prone DNA polymerase, global transcription machinery engineering (gTME), random knockout/overexpression libraries, ribosome engineering, multiplex automated genome engineering (MAGE), customized optimization of metabolic pathways by combinatorial transcriptional engineering (COMPACTER), and library construction of "tunable intergenic regions" (TIGR). Since combinatorial approaches and high-throughput screening methods are fundamentally interconnected, color/fluorescence-based, growth-based, and biosensor-based high-throughput screening methods have been reviewed. We believe that with the help of metabolic engineering tools and new combinatorial approaches, plus effective high-throughput screening methods, researchers will be able to achieve better results on improving microorganism performance under stress or enhancing biochemical yield.

  12. The high throughput biomedicine unit at the institute for molecular medicine Finland: high throughput screening meets precision medicine.

    PubMed

    Pietiainen, Vilja; Saarela, Jani; von Schantz, Carina; Turunen, Laura; Ostling, Paivi; Wennerberg, Krister

    2014-05-01

    The High Throughput Biomedicine (HTB) unit at the Institute for Molecular Medicine Finland FIMM was established in 2010 to serve as a national and international academic screening unit providing access to state of the art instrumentation for chemical and RNAi-based high throughput screening. The initial focus of the unit was multiwell plate based chemical screening and high content microarray-based siRNA screening. However, over the first four years of operation, the unit has moved to a more flexible service platform where both chemical and siRNA screening is performed at different scales primarily in multiwell plate-based assays with a wide range of readout possibilities with a focus on ultraminiaturization to allow for affordable screening for the academic users. In addition to high throughput screening, the equipment of the unit is also used to support miniaturized, multiplexed and high throughput applications for other types of research such as genomics, sequencing and biobanking operations. Importantly, with the translational research goals at FIMM, an increasing part of the operations at the HTB unit is being focused on high throughput systems biological platforms for functional profiling of patient cells in personalized and precision medicine projects.

  13. Insights to transcriptional networks by using high throughput RNAi strategies

    PubMed Central

    Mattila, Jaakko

    2010-01-01

    RNA interference (RNAi) is a powerful method to unravel the role of a given gene in eukaryotic cells. The development of high throughput assay platforms such as fluorescence plate readers and high throughput microscopy has allowed the design of genome wide RNAi screens to systemically discern members of regulatory networks around various cellular processes. Here we summarize the different strategies employed in RNAi screens to reveal regulators of transcriptional networks. We focus our discussion in experimental approaches designed to uncover regulatory interactions modulating transcription factor activity. PMID:19952073

  14. Advances in high throughput DNA sequence data compression.

    PubMed

    Sardaraz, Muhammad; Tahir, Muhammad; Ikram, Ataul Aziz

    2016-06-01

    Advances in high throughput sequencing technologies and reduction in cost of sequencing have led to exponential growth in high throughput DNA sequence data. This growth has posed challenges such as storage, retrieval, and transmission of sequencing data. Data compression is used to cope with these challenges. Various methods have been developed to compress genomic and sequencing data. In this article, we present a comprehensive review of compression methods for genome and reads compression. Algorithms are categorized as referential or reference free. Experimental results and comparative analysis of various methods for data compression are presented. Finally, key challenges and research directions in DNA sequence data compression are highlighted. PMID:26846812

  15. High-throughput screening to identify inhibitors of lysine demethylases.

    PubMed

    Gale, Molly; Yan, Qin

    2015-01-01

    Lysine demethylases (KDMs) are epigenetic regulators whose dysfunction is implicated in the pathology of many human diseases including various types of cancer, inflammation and X-linked intellectual disability. Particular demethylases have been identified as promising therapeutic targets, and tremendous efforts are being devoted toward developing suitable small-molecule inhibitors for clinical and research use. Several High-throughput screening strategies have been developed to screen for small-molecule inhibitors of KDMs, each with advantages and disadvantages in terms of time, cost, effort, reliability and sensitivity. In this Special Report, we review and evaluate the High-throughput screening methods utilized for discovery of novel small-molecule KDM inhibitors.

  16. High-throughput acoustic separation of platelets from whole blood.

    PubMed

    Chen, Yuchao; Wu, Mengxi; Ren, Liqiang; Liu, Jiayang; Whitley, Pamela H; Wang, Lin; Huang, Tony Jun

    2016-09-21

    Platelets contain growth factors which are important in biomedical and clinical applications. In this work, we present an acoustic separation device for high-throughput, non-invasive platelet isolation. In particular, we separated platelets from whole blood at a 10 mL min(-1) throughput, which is three orders of magnitude greater than that of existing acoustic-based platelet separation techniques. Without sample dilution, we observed more than 80% RBC/WBC removal and platelet recovery. High throughput, high separation efficiency, and biocompatibility make this device useful for many clinical applications. PMID:27477388

  17. High-throughput acoustic separation of platelets from whole blood.

    PubMed

    Chen, Yuchao; Wu, Mengxi; Ren, Liqiang; Liu, Jiayang; Whitley, Pamela H; Wang, Lin; Huang, Tony Jun

    2016-09-21

    Platelets contain growth factors which are important in biomedical and clinical applications. In this work, we present an acoustic separation device for high-throughput, non-invasive platelet isolation. In particular, we separated platelets from whole blood at a 10 mL min(-1) throughput, which is three orders of magnitude greater than that of existing acoustic-based platelet separation techniques. Without sample dilution, we observed more than 80% RBC/WBC removal and platelet recovery. High throughput, high separation efficiency, and biocompatibility make this device useful for many clinical applications.

  18. Screening and synthesis: high throughput technologies applied to parasitology.

    PubMed

    Morgan, R E; Westwood, N J

    2004-01-01

    High throughput technologies continue to develop in response to the challenges set by the genome projects. This article discusses how the techniques of both high throughput screening (HTS) and synthesis can influence research in parasitology. Examples of the use of targeted and phenotype-based HTS using unbiased compound collections are provided. The important issue of identifying the protein target(s) of bioactive compounds is discussed from the synthetic chemist's perspective. This article concludes by reviewing recent examples of successful target identification studies in parasitology.

  19. Perspective: Data infrastructure for high throughput materials discovery

    NASA Astrophysics Data System (ADS)

    Pfeif, E. A.; Kroenlein, K.

    2016-05-01

    Computational capability has enabled materials design to evolve from trial-and-error towards more informed methodologies that require large amounts of data. Expert-designed tools and their underlying databases facilitate modern-day high throughput computational methods. Standard data formats and communication standards increase the impact of traditional data, and applying these technologies to a high throughput experimental design provides dense, targeted materials data that are valuable for material discovery. Integrated computational materials engineering requires both experimentally and computationally derived data. Harvesting these comprehensively requires different methods of varying degrees of automation to accommodate variety and volume. Issues of data quality persist independent of type.

  20. Substrate independent ATPase activity may complicate high throughput screening.

    PubMed

    Tuntland, Micheal L; Fung, L W-M

    2016-10-01

    Inorganic phosphate release, [Pi], is often measured in an enzymatic reaction in a high throughput setting. Based on the published mechanism, we designed a protocol for our screening for inhibitors of SAICAR synthetase (PurC), and we found a gradual increase in [Pi] in positive control samples over the course of the day. Further investigation indicated that hydrolysis of ATP catalyzed by PurC, rather than substrate-related phosphate release, was responsible for a partial contribution to the signals in the control samples. Thus substrate-independent ATPase activity may complicate high throughput screening. PMID:27430931

  1. Identification of Selective Inhibitors of the Plasmodium falciparum Hexose Transporter PfHT by Screening Focused Libraries of Anti-Malarial Compounds

    PubMed Central

    Johnson, Alex; Elya, Carolyn; Anderson, Johanna; Clark, Julie; Connelly, Michele; Yang, Lei; Min, Jaeki; Sato, Yuko; Guy, R. Kiplin; Landfear, Scott M.

    2015-01-01

    Development of resistance against current antimalarial drugs necessitates the search for novel drugs that interact with different targets and have distinct mechanisms of action. Malaria parasites depend upon high levels of glucose uptake followed by inefficient metabolic utilization via the glycolytic pathway, and the Plasmodium falciparum hexose transporter PfHT, which mediates uptake of glucose, has thus been recognized as a promising drug target. This transporter is highly divergent from mammalian hexose transporters, and it appears to be a permease that is essential for parasite viability in intra-erythrocytic, mosquito, and liver stages of the parasite life cycle. An assay was developed that is appropriate for high throughput screening against PfHT based upon heterologous expression of PfHT in Leishmania mexicana parasites that are null mutants for their endogenous hexose transporters. Screening of two focused libraries of antimalarial compounds identified two such compounds that are high potency selective inhibitors of PfHT compared to human GLUT1. Additionally, 7 other compounds were identified that are lower potency and lower specificity PfHT inhibitors but might nonetheless serve as starting points for identification of analogs with more selective properties. These results further support the potential of PfHT as a novel drug target. PMID:25894322

  2. Antimalarial drug interactions of compounds isolated from Kigelia africana (Bignoniaceae) and their synergism with artemether, against the multidrug-resistant W2mef Plasmodium falciparum strain.

    PubMed

    Zofou, Denis; Tene, Mathieu; Tane, Pierre; Titanji, Vincent P K

    2012-02-01

    For decades, drug resistance has been the major obstacle in the fight against malaria, and the search for new drugs together with the combination therapy constitutes the major approach in responding to this situation. The present study aims at assessing the in vitro antimalarial activity of four compounds isolated from Kigelia africana stem bark (atranorin - KAE1, specicoside - KAE7, 2β,3β,19α-trihydroxy-urs-12-20-en-28-oic acid - KAE3, and p-hydroxy-cinnamic acid - KAE10) and their drug interactions among themselves and their combination effects with quinine and artemether. The antiplasmodial activity and drug interactions were evaluated against the multidrug-resistant W2mef strain of Plasmodium falciparum using the parasite lactate dehydrogenase assay. Three of the four compounds tested were significantly active against W2mef: specicoside (IC(50) = 1.02 ± 0.17 μM), 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid (IC(50) = 1.86 ± 0.15 μM) and atranorin (IC(50) = 1.78 ± 0.18 μM), whereas p-hydroxy-cinnamic acid showed a weak activity (IC(50) = 12.89 ± 0.87 μM). A slight synergistic effect was observed between atranorin and 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid (Combination index, CI = 0.82) whereas the interaction between specicoside and p-hydroxy-cinnamic acid were instead antagonistic (CI = 2.67). All the three compounds showed synergistic effects with artemether, unlike the slight antagonistic interactions of atranorin and 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid in combination with quinine. K. africana compounds are therefore likely to serve as leads in the development of new partner drugs in artemether-based combination therapy. PMID:21814840

  3. High Throughput Screening for Inhibitors of Mycobacterium tuberculosis H37Rv

    PubMed Central

    ANANTHAN, SUBRAMANIAM; FAALEOLEA, ELLEN R.; GOLDMAN, ROBERT C.; HOBRATH, JUDITH V.; KWONG, CECIL D.; LAUGHON, BARBARA E.; MADDRY, JOSEPH A.; MEHTA, ALKA; RASMUSSEN, LYNN; REYNOLDS, ROBERT C.; SECRIST, JOHN A.; SHINDO, NICE; SHOWE, DUSTIN N.; SOSA, MELINDA I.; SULING, WILLIAM J.; WHITE, E. LUCILE

    2009-01-01

    SUMMARY There is an urgent need for the discovery and development of new antitubercular agents that target new biochemical pathways and treat drug resistant forms of the disease. One approach to addressing this need is through high throughput screening of medicinally relevant libraries against the whole bacterium in order to discover a variety of new, active scaffolds that will stimulate new biological research and drug discovery. Through the Tuberculosis Antimicrobial Acquisition and Coordinating Facility (www.taacf.org), a large, medicinally relevant chemical library was screened against M. tuberculosis strain H37Rv. The screening methods and a medicinal chemistry analysis of the results are reported herein. PMID:19758845

  4. High-Throughput Screening of Tyrosine Kinase Inhibitor Resistant Genes in CML.

    PubMed

    Ma, Leyuan; Roderick, Justine; Kelliher, Michelle A; Green, Michael R

    2016-01-01

    Genome-wide RNA interference (RNAi) screening in mammalian cells has proven to be a powerful tool for identifying new genes and molecular pathways relevant to many cellular processes and diseases. For example, screening for genes that, when inactivated, lead to resistance to cancer therapeutic drugs can reveal new mechanisms for how resistance develops and identify potential targetable strategies to overcome drug resistance. Here, we describe a detailed procedure for performing a high-throughput RNAi screen using a genome-wide human short hairpin RNA (shRNA) library for identifying tyrosine kinase inhibitor (TKI)-resistance genes in a human CML cell line model. PMID:27581147

  5. Immunoliposome-mediated drug delivery to Plasmodium-infected and non-infected red blood cells as a dual therapeutic/prophylactic antimalarial strategy.

    PubMed

    Moles, Ernest; Urbán, Patricia; Jiménez-Díaz, María Belén; Viera-Morilla, Sara; Angulo-Barturen, Iñigo; Busquets, Maria Antònia; Fernàndez-Busquets, Xavier

    2015-07-28

    One of the most important factors behind resistance evolution in malaria is the failure to deliver sufficiently high amounts of drugs to early stages of Plasmodium-infected red blood cells (pRBCs). Despite having been considered for decades as a promising approach, the delivery of antimalarials encapsulated in immunoliposomes targeted to pRBCs has not progressed towards clinical applications, whereas in vitro assays rarely reach drug efficacy improvements above 10-fold. Here we show that encapsulation efficiencies reaching >96% are achieved for the weak basic drugs chloroquine (CQ) and primaquine using the pH gradient loading method in liposomes containing neutral saturated phospholipids. Targeting antibodies are best conjugated through their primary amino groups, adjusting chemical crosslinker concentration to retain significant antigen recognition. Antigens from non-parasitized RBCs have also been considered as targets for the delivery to the cell of drugs not affecting the erythrocytic metabolism. Using this strategy, we have achieved unprecedented complete nanocarrier targeting to early intraerythrocytic stages of the malaria parasite for which there is a lack of specific extracellular molecular tags. Immunoliposomes studded with monoclonal antibodies raised against the erythrocyte surface protein glycophorin A were capable of targeting 100% RBCs and pRBCs at the low concentration of 0.5μM total lipid in the culture, with >95% of added liposomes retained on cell surfaces. When exposed for only 15min to Plasmodium falciparum in vitro cultures of early stages, free CQ had no significant effect on the viability of the parasite up to 200nM, whereas immunoliposomal 50nM CQ completely arrested its growth. In vivo assays in mice showed that immunoliposomes cleared the pathogen below detectable levels at a CQ dose of 0.5mg/kg, whereas free CQ administered at 1.75mg/kg was, at most, 40-fold less efficient. Our data suggest that this significant improvement is in part

  6. Antimalarial Activity of Cupredoxins

    PubMed Central

    Cruz-Gallardo, Isabel; Díaz-Moreno, Irene; Díaz-Quintana, Antonio; Donaire, Antonio; Velázquez-Campoy, Adrián; Curd, Rachel D.; Rangachari, Kaveri; Birdsall, Berry; Ramos, Andres; Holder, Anthony A.; De la Rosa, Miguel A.

    2013-01-01

    The discovery of effective new antimalarial agents is urgently needed. One of the most frequently studied molecules anchored to the parasite surface is the merozoite surface protein-1 (MSP1). At red blood cell invasion MSP1 is proteolytically processed, and the 19-kDa C-terminal fragment (MSP119) remains on the surface and is taken into the red blood cell, where it is transferred to the food vacuole and persists until the end of the intracellular cycle. Because a number of specific antibodies inhibit erythrocyte invasion and parasite growth, MSP119 is therefore a promising target against malaria. Given the structural homology of cupredoxins with the Fab domain of monoclonal antibodies, an approach combining NMR and isothermal titration calorimetry (ITC) measurements with docking calculations based on BiGGER is employed on MSP119-cupredoxin complexes. Among the cupredoxins tested, rusticyanin forms a well defined complex with MSP119 at a site that overlaps with the surface recognized by the inhibitory antibodies. The addition of holo-rusticyanin to infected cells results in parasitemia inhibition, but negligible effects on parasite growth can be observed for apo-rusticyanin and other proteins of the cupredoxin family. These findings point to rusticyanin as an excellent therapeutic tool for malaria treatment and provide valuable information for drug design. PMID:23749994

  7. Live Cell Bioluminescence Imaging in Temporal Reaction of G Protein-Coupled Receptor for High-Throughput Screening and Analysis.

    PubMed

    Hattori, Mitsuru; Ozawa, Takeaki

    2016-01-01

    G protein-coupled receptors (GPCRs) are notable targets of basic therapeutics. Many screening methods have been established to identify novel agents for GPCR signaling in a high-throughput manner. However, information related to the temporal reaction of GPCR with specific ligands remains poor. We recently developed a bioluminescence method for the quantitative detection of the interaction between GPCR and β-arrestin using split luciferase complementation. To monitor time-course variation of the interactions, a new imaging system contributes to the accurate evaluation of drugs for GPCRs in a high-throughput manner. PMID:27424906

  8. Live Cell Bioluminescence Imaging in Temporal Reaction of G Protein-Coupled Receptor for High-Throughput Screening and Analysis.

    PubMed

    Hattori, Mitsuru; Ozawa, Takeaki

    2016-01-01

    G protein-coupled receptors (GPCRs) are notable targets of basic therapeutics. Many screening methods have been established to identify novel agents for GPCR signaling in a high-throughput manner. However, information related to the temporal reaction of GPCR with specific ligands remains poor. We recently developed a bioluminescence method for the quantitative detection of the interaction between GPCR and β-arrestin using split luciferase complementation. To monitor time-course variation of the interactions, a new imaging system contributes to the accurate evaluation of drugs for GPCRs in a high-throughput manner.

  9. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    NASA Astrophysics Data System (ADS)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, <30% of drugs withdrawals from the market were due to cardiac toxicity, where unintended interactions with ion channels disrupt the heart's normal electrical function. Consequently, all new drugs must undergo preclinical testing for cardiac liability, adding to an already expensive and lengthy process. Recognition that proarrhythmic effects often result from drug action on multiple ion channels demonstrates a need for integrative and comprehensive measurements. Additionally, patient-specific therapies relying on emerging technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  10. High-throughput screening, predictive modeling and computational embryology - Abstract

    EPA Science Inventory

    High-throughput screening (HTS) studies are providing a rich source of data that can be applied to chemical profiling to address sensitivity and specificity of molecular targets, biological pathways, cellular and developmental processes. EPA’s ToxCast project is testing 960 uniq...

  11. Accounting For Uncertainty in The Application Of High Throughput Datasets

    EPA Science Inventory

    The use of high throughput screening (HTS) datasets will need to adequately account for uncertainties in the data generation process and propagate these uncertainties through to ultimate use. Uncertainty arises at multiple levels in the construction of predictors using in vitro ...

  12. High Throughput Assays and Exposure Science (ISES annual meeting)

    EPA Science Inventory

    High throughput screening (HTS) data characterizing chemical-induced biological activity has been generated for thousands of environmentally-relevant chemicals by the US inter-agency Tox21 and the US EPA ToxCast programs. For a limited set of chemicals, bioactive concentrations r...

  13. High Throughput Exposure Estimation Using NHANES Data (SOT)

    EPA Science Inventory

    In the ExpoCast project, high throughput (HT) exposure models enable rapid screening of large numbers of chemicals for exposure potential. Evaluation of these models requires empirical exposure data and due to the paucity of human metabolism/exposure data such evaluations includ...

  14. High-throughput glycoanalytical technology for systems glycobiology.

    PubMed

    Liu, Li; Telford, Jayne E; Knezevic, Ana; Rudd, Pauline M

    2010-10-01

    The development of glycoanalytical HPLC-based high-throughput technology has greatly enhanced the study of glycobiology, facilitating the discovery of disease-related solutions and providing an informative view of glycosylation and its relationship with other biological disciplines in a systems biology approach.

  15. New High Throughput Methods to Estimate Chemical Exposure

    EPA Science Inventory

    EPA has made many recent advances in high throughput bioactivity testing. However, concurrent advances in rapid, quantitative prediction of human and ecological exposures have been lacking, despite the clear importance of both measures for a risk-based approach to prioritizing an...

  16. Environmental Impact on Vascular Development Predicted by High Throughput Screening

    EPA Science Inventory

    Understanding health risks to embryonic development from exposure to environmental chemicals is a significant challenge given the diverse chemical landscape and paucity of data for most of these compounds. High throughput screening (HTS) in EPA’s ToxCastTM project provides vast d...

  17. High-throughput production of two disulphide-bridge toxins.

    PubMed

    Upert, Grégory; Mourier, Gilles; Pastor, Alexandra; Verdenaud, Marion; Alili, Doria; Servent, Denis; Gilles, Nicolas

    2014-08-01

    A quick and efficient production method compatible with high-throughput screening was developed using 36 toxins belonging to four different families of two disulphide-bridge toxins. Final toxins were characterized using HPLC co-elution, CD and pharmacological studies.

  18. High-Throughput Screening for Streptomyces Antibiotic Biosynthesis Activators

    PubMed Central

    Chen, Li; Wang, Yemin; Guo, Hang; Xu, Min; Deng, Zixin

    2012-01-01

    A genomic cosmid library of Streptomyces clavuligerus was constructed and transferred efficiently by conjugation to Streptomyces lividans, and 12 distinct groups of overlapping cosmid clones that activated the silent actinorhodin biosynthesis gene cluster were identified. This generally applicable high-throughput screening procedure greatly facilitates the identification of antibiotic biosynthesis activators. PMID:22504805

  19. High-Throughput Sequencing and Rare Genetic Diseases

    PubMed Central

    Makrythanasis, P.; Antonarakis, S.E.

    2012-01-01

    High-throughput sequencing has drastically changed the research of genes responsible for genetic disorders and is now gradually introduced as an additional genetic diagnostic testing in clinical practice. The current debates on the emerging technical, medical and ethical issues as well as the potential optimum use of the available technology are discussed. PMID:23293577

  20. High-throughput screening, predictive modeling and computational embryology

    EPA Science Inventory

    High-throughput screening (HTS) studies are providing a rich source of data that can be applied to profile thousands of chemical compounds for biological activity and potential toxicity. EPA’s ToxCast™ project, and the broader Tox21 consortium, in addition to projects worldwide,...

  1. Fully Bayesian Analysis of High-throughput Targeted Metabolomics Assays

    EPA Science Inventory

    High-throughput metabolomic assays that allow simultaneous targeted screening of hundreds of metabolites have recently become available in kit form. Such assays provide a window into understanding changes to biochemical pathways due to chemical exposure or disease, and are usefu...

  2. Combinatorial/high throughput methods for the determination of polyanhydride phase behavior.

    PubMed

    Thorstenson, Jon B; Petersen, Latrisha K; Narasimhan, Balaji

    2009-01-01

    Combinatorial methods have been developed to study the phase behavior of biodegradable polyanhydrides for drug delivery applications. The polyanhydrides of interest are poly[1,6-bis(p-carboxyphenoxy) hexane] (CPH) and poly[sebacic anhydride] (SA). Both continuous and discrete polymer blend libraries were fabricated by using a combination of solution-based gradient deposition and rapid prototyping. Blend compositions were characterized via a high throughput transmission Fourier transform infrared (FTIR) sampling technique and compared against theoretical mass balance predictions. To obtain phase diagrams of CPH/SA, the effect of blend composition and annealing temperature on the miscibility of the blend was studied. This gradient library was observed with optical microscopy in order to determine cloud points. These results were compared with a theoretical phase diagram obtained from Flory-Huggins theory and with atomic force microscopy (AFM) experiments on blend libraries and the agreement between the methods was very good. The high throughput method demonstrates that the CPH/SA system exhibits upper critical solution temperature behavior. These libraries are amenable to other high throughput applications in biomaterials science including cell viability, cell activation, and protein/biomaterial interactions.

  3. A high throughput array microscope for the mechanical characterization of biomaterials

    NASA Astrophysics Data System (ADS)

    Cribb, Jeremy; Osborne, Lukas D.; Hsiao, Joe Ping-Lin; Vicci, Leandra; Meshram, Alok; O'Brien, E. Tim; Spero, Richard Chasen; Taylor, Russell; Superfine, Richard

    2015-02-01

    In the last decade, the emergence of high throughput screening has enabled the development of novel drug therapies and elucidated many complex cellular processes. Concurrently, the mechanobiology community has developed tools and methods to show that the dysregulation of biophysical properties and the biochemical mechanisms controlling those properties contribute significantly to many human diseases. Despite these advances, a complete understanding of the connection between biomechanics and disease will require advances in instrumentation that enable parallelized, high throughput assays capable of probing complex signaling pathways, studying biology in physiologically relevant conditions, and capturing specimen and mechanical heterogeneity. Traditional biophysical instruments are unable to meet this need. To address the challenge of large-scale, parallelized biophysical measurements, we have developed an automated array high-throughput microscope system that utilizes passive microbead diffusion to characterize mechanical properties of biomaterials. The instrument is capable of acquiring data on twelve-channels simultaneously, where each channel in the system can independently drive two-channel fluorescence imaging at up to 50 frames per second. We employ this system to measure the concentration-dependent apparent viscosity of hyaluronan, an essential polymer found in connective tissue and whose expression has been implicated in cancer progression.

  4. High Throughput Label Free Measurement of Cancer Cell Adhesion Kinetics Under Hemodynamic Flow

    PubMed Central

    Spencer, Adrianne; Baker, Aaron B.

    2016-01-01

    The kinetics of receptor-mediated cell adhesion to extracellular matrix and adherent cell monolayers plays a key role in many physiological and pathological processes including cancer metastasis. Within this process the presence of fluidic shear forces is a key regulator of binding equilibrium and kinetics of cell adhesion. Current techniques to examine the kinetics of cell adhesion are either performed in the absence of flow or are low throughput, limiting their application to pharmacological compound screening or the high throughput investigation of biological mechanisms. We developed a high throughput flow device that applies flow in a multi-well format and interfaced this system with electric cell-substrate impedance sensing (ECIS) system to allow label free detection of cell adhesion. We demonstrate that this combined system is capable of making real time measurements of cancer cell adhesion to extracellular matrix and immobilized platelets. In addition, we examined the dependence of the kinetics of binding of cancer cells on the level of shear stress and in the presence of small molecule inhibitors to adhesion-related pathways. This versatile system is broadly adaptable to the high throughput study of cell adhesion kinetics for many applications including drug screening and the investigation of the mechanisms of cancer metastasis. PMID:26816215

  5. Droplet microfluidic technology for single-cell high-throughput screening.

    PubMed

    Brouzes, Eric; Medkova, Martina; Savenelli, Neal; Marran, Dave; Twardowski, Mariusz; Hutchison, J Brian; Rothberg, Jonathan M; Link, Darren R; Perrimon, Norbert; Samuels, Michael L

    2009-08-25

    We present a droplet-based microfluidic technology that enables high-throughput screening of single mammalian cells. This integrated platform allows for the encapsulation of single cells and reagents in independent aqueous microdroplets (1 pL to 10 nL volumes) dispersed in an immiscible carrier oil and enables the digital manipulation of these reactors at a very high-throughput. Here, we validate a full droplet screening workflow by conducting a droplet-based cytotoxicity screen. To perform this screen, we first developed a droplet viability assay that permits the quantitative scoring of cell viability and growth within intact droplets. Next, we demonstrated the high viability of encapsulated human monocytic U937 cells over a period of 4 days. Finally, we developed an optically-coded droplet library enabling the identification of the droplets composition during the assay read-out. Using the integrated droplet technology, we screened a drug library for its cytotoxic effect against U937 cells. Taken together our droplet microfluidic platform is modular, robust, uses no moving parts, and has a wide range of potential applications including high-throughput single-cell analyses, combinatorial screening, and facilitating small sample analyses. PMID:19617544

  6. A high throughput array microscope for the mechanical characterization of biomaterials

    PubMed Central

    Cribb, Jeremy; Osborne, Lukas D.; Hsiao, Joe Ping-Lin; Vicci, Leandra; Meshram, Alok; O’Brien, E. Tim; Spero, Richard Chasen; Taylor, Russell; Superfine, Richard

    2015-01-01

    In the last decade, the emergence of high throughput screening has enabled the development of novel drug therapies and elucidated many complex cellular processes. Concurrently, the mechanobiology community has developed tools and methods to show that the dysregulation of biophysical properties and the biochemical mechanisms controlling those properties contribute significantly to many human diseases. Despite these advances, a complete understanding of the connection between biomechanics and disease will require advances in instrumentation that enable parallelized, high throughput assays capable of probing complex signaling pathways, studying biology in physiologically relevant conditions, and capturing specimen and mechanical heterogeneity. Traditional biophysical instruments are unable to meet this need. To address the challenge of large-scale, parallelized biophysical measurements, we have developed an automated array high-throughput microscope system that utilizes passive microbead diffusion to characterize mechanical properties of biomaterials. The instrument is capable of acquiring data on twelve-channels simultaneously, where each channel in the system can independently drive two-channel fluorescence imaging at up to 50 frames per second. We employ this system to measure the concentration-dependent apparent viscosity of hyaluronan, an essential polymer found in connective tissue and whose expression has been implicated in cancer progression. PMID:25725856

  7. Reducing false positive findings in statistical analysis of pharmacogenomic biomarker studies using high-throughput technologies.

    PubMed

    Matsui, Shigeyuki

    2006-05-01

    The promise of pharmacogenomics lies in the potential to establish a personalized drug therapy with the intent of maximizing effectiveness and minimizing risk, through development of pharmacogenomics biomarkers. However, currently, most pharmacogenomic measurements are not considered valid biomarkers with clear clinical significance, thus this field is in early developmental stages. Recently, the development of comprehensive, high-throughput technologies such as gene expression microarrays has provided powerful new tools for these stages. This technological transformation is, at the same time, generating an increasing demand for statistical analysis of large and complex multivariate datasets from high-throughput assays. This article provides a review of the key features to be observed in statistical analyses of large amounts of data from pharmacogenomic biomarker studies with high-throughput assays. The problem of false positive can be very serious in such studies. The evaluation of stability and reproducibility of the results of statistical analysis are claimed to reduce chance that false positive findings are subject to further investigation in subsequent studies.

  8. Repurposing the anti-malarial drug artesunate as a novel therapeutic agent for metastatic renal cell carcinoma due to its attenuation of tumor growth, metastasis, and angiogenesis

    PubMed Central

    Lim, Sharon; Lee, Se Jeong; Lim, Joung Eun; Nam, Do-Hyun; Joo, Kyeung Min; Jeong, Byong Chang; Jeon, Seong Soo; Choi, Han Yong; Lee, Hye Won

    2015-01-01

    Despite advances in the development of molecularly targeted therapies, metastatic renal cell carcinoma (RCC) is still incurable. Artesunate (ART), a well-known anti-malarial drug with low toxicity, exhibits highly selective anti-tumor actions against various tumors through generation of cytotoxic carbon-centered free radical in the presence of free iron. However, the therapeutic efficacy of ART against metastatic RCC has not yet been fully elucidated. In the analysis on a dataset from The Cancer Genome Atlas (TCGA) (n = 469) and a tissue microarray set from Samsung Medical Center (n = 119) from a cohort of patients with clear cell RCC (ccRCC), up-regulation of transferrin receptor 1 (TfR1), which is a well-known predictive marker for ART, was correlated with the presence of distant metastasis and an unfavorable prognosis. Moreover, ART exerted potent selective cytotoxicity against human RCC cell lines (Caki-1, 786-O, and SN12C-GFP-SRLu2) and sensitized these cells to sorafenib in vitro, and the extent of ART cytotoxicity correlated with TfR1 expression. ART-mediated growth inhibition of human RCC cell lines was shown to result from the induction of cell cycle arrest at the G2/M phase and oncosis-like cell death. Furthermore, ART inhibited cell clonogenicity and invasion of human RCC cells and anti-angiogenic effects in vitro in a dose-dependent manner. Consistent with these in vitro data, anti-tumor, anti-metastatic and anti-angiogenic effects of ART were also validated in human 786-O xenografts. Taken together, ART is a promising novel candidate for treating human RCC, either alone or in combination with other therapies. PMID:26426994

  9. Methodological Issues in the Assessment of Antimalarial Drug Treatment: Analysis of 13 Studies in Eight African Countries from 2001 to 2004▿

    PubMed Central

    Guthmann, Jean-Paul ; Pinoges, Loretxu; Checchi, Francesco; Cousens, Simon; Balkan, Suna; van Herp, Michel ; Legros, Dominique; Olliaro, Piero

    2006-01-01

    The objectives of these analyses were to assess the feasibility of the latest WHO recommendations (28-day follow-up with PCR genotyping) for the assessment of antimalarial drug efficacy in vivo and to examine how different statistical approaches affect results. We used individual-patient data from 13 studies of uncomplicated pediatric falciparum malaria conducted in sub-Saharan Africa, using chloroquine (CQ), sulfadoxine/pyrimethamine (SP), or amodiaquine (AQ). We assessed the use effectiveness and test performance of PCR genotyping in distinguishing recurrent infections. In analyzing data, we compared (i) the risk of failure on target days (days 14 and 28) by using Kaplan-Meier and per-protocol evaluable patient analyses, (ii) PCR-corrected results allowing (method 1) or excluding (method 2) new infections, (iii) and day 14 versus day 28 results. Of the 2,576 patients treated, 2,287 (89%) were evaluable on day 28. Of the 695 recurrences occurring post-day 14, 650 could be processed and 584 were resolved (PCR use effectiveness, 84%; test performance, 90%). The risks of failure on day 28 with Kaplan-Meier and evaluable-patient analyses tended to be generally close (except in smaller studies) because the numbers of dropouts were minimal, but attrition rates on day 28 were higher with the latter method. Method 2 yielded higher risks of failure than method 1. Extending observation to 28 days produced higher estimated risks of failure for SP and AQ but not for CQ (high failure rates by day 14). Results support the implementation of the current WHO protocol and favor analyzing PCR-corrected outcomes by Kaplan-Meier analysis (which allows for dropouts) and retaining new infections (which minimizes losses). PMID:16954313

  10. Oral treatments of Echinococcus multilocularis-infected mice with the antimalarial drug mefloquine that potentially interacts with parasite ferritin and cystatin.

    PubMed

    Küster, Tatiana; Stadelmann, Britta; Rufener, Reto; Risch, Corina; Müller, Joachim; Hemphill, Andrew

    2015-11-01

    This study investigated the effects of oral treatments of Echinococcus multilocularis-infected mice with the antimalarial drug mefloquine (MEF) and identified proteins that bind to MEF in parasite extracts and human cells by affinity chromatography. In a pilot experiment, MEF treatment was applied 5 days per week and was intensified by increasing the dosage stepwise from 12.5 mg/kg to 200 mg/kg during 4 weeks followed by treatments of 100 mg/kg during the last 7 weeks. This resulted in a highly significant reduction of parasite weight in MEF-treated mice compared with mock-treated mice, but the reduction was significantly less efficacious compared with the standard treatment regimen of albendazole (ABZ). In a second experiment, MEF was applied orally in three different treatment groups at dosages of 25, 50 or 100 mg/kg, but only twice a week, for a period of 12 weeks. Treatment at 100 mg/kg had a profound impact on the parasite, similar to ABZ treatment at 200 mg/kg/day (5 days/week for 12 weeks). No adverse side effects were noted. To identify proteins in E. multilocularis metacestodes that physically interact with MEF, affinity chromatography of metacestode extracts was performed on MEF coupled to epoxy-activated Sepharose(®), followed by SDS-PAGE and in-gel digestion LC-MS/MS. This resulted in the identification of E. multilocularis ferritin and cystatin as MEF-binding proteins. In contrast, when human cells were exposed to MEF affinity chromatography, nicotinamide phosphoribosyltransferase was identified as a MEF-binding protein. This indicates that MEF could potentially interact with different proteins in parasites and human cells. PMID:26395219

  11. Factors related to compliance to anti-malarial drug combination: example of amodiaquine/sulphadoxine-pyrimethamine among children in rural Senegal

    PubMed Central

    Souares, Aurélia; Lalou, Richard; Sene, Ibra; Sow, Diarietou; Le Hesran, Jean-Yves

    2009-01-01

    Background The introduction of new anti-malarial treatment that is effective, but more expensive, raises questions about whether the high level of effectiveness observed in clinical trials can be found in a context of family use. The objective of this study was to determine the factors related to adherence, when using the amodiaquine/sulphadoxine-pyrimethamine (AQ/SP) association, a transitory strategy before ACT implementation in Senegal. Methods The study was conducted in five rural dispensaries. Children, between two and 10 years of age, who presented mild malaria were recruited at the time of the consultation and were prescribed AQ/SP. The child's primary caretaker was questioned at home on D3 about treatment compliance and factors that could have influenced his or her adherence to treatment. A logistic regression model was used for the analyses. Results The study sample included 289 children. The adherence rate was 64.7%. Two risks factors for non-adherence were identified: the children's age (8–10 years) (ORa = 3.07 [1.49–6.29]; p = 0.004); and the profession of the head of household (retailer/employee versus farmer) (ORa = 2.71 [1.34–5.48]; p = 0.006). Previously seeking care (ORa = 0.28 [0.105–0.736], p=0.001] satisfaction with received information (ORa = 0.45 [0.24–0.84]; p = 0.013), and the quality of history taking (ORa = 0.38 [0.21–0.69]; p = 0.001) were significantly associated with good compliance. Conclusion The results of the study show the importance of information and communication between caregivers and health center staff. The experience gained from this therapeutic transition emphasizes the importance of information given to the patients at the time of the consultation and drug delivery in order to improve drug use and thus prevent the emergence of rapid drug resistance. PMID:19497103

  12. High-Throughput Screening for Growth Inhibitors Using a Yeast Model of Familial Paraganglioma

    PubMed Central

    Tian, Defeng; Bundrick, Mary; John, Kristen; Holte, Molly Nelson; Her, Yeng F.; Evans, Debra; Saenz, Dyana T.; Poeschla, Eric M.; Hook, Derek; Georg, Gunda; Maher, L. James

    2013-01-01

    Classical tumor suppressor genes block neoplasia by regulating cell growth and death. A remarkable puzzle is therefore presented by familial paraganglioma (PGL), a neuroendocrine cancer where the tumor suppressor genes encode subunits of succinate dehydrogenase (SDH), an enzyme of the tricarboxylic acid (TCA) cycle of central metabolism. Loss of SDH initiates PGL through mechanisms that remain unclear. Could this metabolic defect provide a novel opportunity for chemotherapy of PGL? We report the results of high throughput screening to identify compounds differentially toxic to SDH mutant cells using a powerful S. cerevisiae (yeast) model of PGL. Screening more than 200,000 compounds identifies 12 compounds that are differentially toxic to SDH-mutant yeast. Interestingly, two of the agents, dequalinium and tetraethylthiuram disulfide (disulfiram), are anti-malarials with the latter reported to be a glycolysis inhibitor. We show that four of the additional hits are potent inhibitors of yeast alcohol dehydrogenase. Because alcohol dehydrogenase regenerates NAD+ in glycolytic cells that lack TCA cycle function, this result raises the possibility that lactate dehydrogenase, which plays the equivalent role in human cells, might be a target of interest for PGL therapy. We confirm that human cells deficient in SDH are differentially sensitive to a lactate dehydrogenase inhibitor. PMID:23451094

  13. High-throughput screening for growth inhibitors using a yeast model of familial paraganglioma.

    PubMed

    Bancos, Irina; Bida, John Paul; Tian, Defeng; Bundrick, Mary; John, Kristen; Holte, Molly Nelson; Her, Yeng F; Evans, Debra; Saenz, Dyana T; Poeschla, Eric M; Hook, Derek; Georg, Gunda; Maher, L James

    2013-01-01

    Classical tumor suppressor genes block neoplasia by regulating cell growth and death. A remarkable puzzle is therefore presented by familial paraganglioma (PGL), a neuroendocrine cancer where the tumor suppressor genes encode subunits of succinate dehydrogenase (SDH), an enzyme of the tricarboxylic acid (TCA) cycle of central metabolism. Loss of SDH initiates PGL through mechanisms that remain unclear. Could this metabolic defect provide a novel opportunity for chemotherapy of PGL? We report the results of high throughput screening to identify compounds differentially toxic to SDH mutant cells using a powerful S. cerevisiae (yeast) model of PGL. Screening more than 200,000 compounds identifies 12 compounds that are differentially toxic to SDH-mutant yeast. Interestingly, two of the agents, dequalinium and tetraethylthiuram disulfide (disulfiram), are anti-malarials with the latter reported to be a glycolysis inhibitor. We show that four of the additional hits are potent inhibitors of yeast alcohol dehydrogenase. Because alcohol dehydrogenase regenerates NAD(+) in glycolytic cells that lack TCA cycle function, this result raises the possibility that lactate dehydrogenase, which plays the equivalent role in human cells, might be a target of interest for PGL therapy. We confirm that human cells deficient in SDH are differentially sensitive to a lactate dehydrogenase inhibitor.

  14. Current trends in virtual high throughput screening using ligand-based and structure-based methods.

    PubMed

    Sukumar, Nagamani; Das, Sourav

    2011-12-01

    High throughput in silico methods have offered the tantalizing potential to drastically accelerate the drug discovery process. Yet despite significant efforts expended by academia, national labs and industry over the years, many of these methods have not lived up to their initial promise of reducing the time and costs associated with the drug discovery enterprise, a process that can typically take over a decade and cost hundreds of millions of dollars from conception to final approval and marketing of a drug. Nevertheless structure-based modeling has become a mainstay of computational biology and medicinal chemistry, helping to leverage our knowledge of the biological target and the chemistry of protein-ligand interactions. While ligand-based methods utilize the chemistry of molecules that are known to bind to the biological target, structure-based drug design methods rely on knowledge of the three-dimensional structure of the target, as obtained through crystallographic, spectroscopic or bioinformatics techniques. Here we review recent developments in the methodology and applications of structure-based and ligand-based methods and target-based chemogenomics in Virtual High Throughput Screening (VHTS), highlighting some case studies of recent applications, as well as current research in further development of these methods. The limitations of these approaches will also be discussed, to give the reader an indication of what might be expected in years to come. PMID:21843144

  15. Investigations of the effects of the antimalarial drug dihydroartemisinin (DHA) using the Frog Embryo Teratogenesis Assay-Xenopus (FETAX).

    PubMed

    Longo, Monica; Zanoncelli, Sara; Della Torre, Paola; Rosa, Francesco; Giusti, AnnaMaria; Colombo, Paolo; Brughera, Marco; Mazué, Guy; Olliaro, Piero

    2008-08-01

    Artemisinin derivatives are effective and safe drugs for treating malaria, but they are not recommended during the first trimester of pregnancy because of resorptions and abnormalities observed in animal reproduction studies. Previous studies in rats showed that artemisinin embryotoxicity derives from the depletion of primitive red blood cells (RBCs) over a narrow critical time window (gestation Days 9-14). In order to further investigate the susceptibility of primitive RBCs to artemisinins and to establish whether this susceptibility is species-specific or inherent to the compound, we studied dihydroartemisinin (DHA), both a drug in its own right and the main metabolite of current artemisinin derivatives in use, in the Frog Embryo Teratogenesis Assay-Xenopus (FETAX). This model readily allows investigation and monitoring of primitive and definitive RBCs. Effects on frog larvae exposed to DHA for 48 h during early embryonic development, starting from 24 h post fertilization, were similar to those on rat embryos in terms of reduction in the number of primitive RBCs (clonally produced within the ventral blood island). In contrast, RBCs of older larvae (stage 47, produced at the definitive sites of hematopoiesis) were affected minimally and subsequently recovered. Compared to rat embryos, the frog larvae had no areas of necrosis but they shared similar heart defects. The mitochondrion appeared to be the main subcellular target, similar to observations in Plasmodium. These results implicate artemisinin-induced embryotoxicity through perturbation of metabolically active RBCs; whereas this mode of action does not appear to be species-specific, the stages of susceptibility varied between different species. The window of susceptibility and duration of exposure must be considered to evaluate the clinical relevance of these findings. PMID:18394862

  16. Multiple column high-throughput e-beam inspection (EBI)

    NASA Astrophysics Data System (ADS)

    Lam, David K.; Monahan, Kevin M.; Liu, Enden D.; Tran, Cong; Prescop, Ted

    2012-03-01

    Single-column e-beam systems are used in production for the detection of electrical defects, but are too slow to be used for the detection of small physical defects, and can't meet future inspection requirements. This paper presents a multiplecolumn e-beam technology for high throughput wafer inspection. Multibeam has developed all-electrostatic columns for high-resolution imaging. The elimination of magnetic coils enables the columns to be small; e-beam deflection is faster in the absence of magnetic hysteresis. Multiple miniaturecolumns are assembled in an array. An array of 100 columns covers the entire surface of a 300mm wafer, affording simultaneous cross-wafer sampling. Column performance simulations and system architecture are presented. Also provided are examples of high throughput, more efficient, multiple-column wafer inspection.

  17. High throughput screening of starch structures using carbohydrate microarrays.

    PubMed

    Tanackovic, Vanja; Rydahl, Maja Gro; Pedersen, Henriette Lodberg; Motawia, Mohammed Saddik; Shaik, Shahnoor Sultana; Mikkelsen, Maria Dalgaard; Krunic, Susanne Langgaard; Fangel, Jonatan Ulrik; Willats, William George Tycho; Blennow, Andreas

    2016-01-01

    In this study we introduce the starch-recognising carbohydrate binding module family 20 (CBM20) from Aspergillus niger for screening biological variations in starch molecular structure using high throughput carbohydrate microarray technology. Defined linear, branched and phosphorylated maltooligosaccharides, pure starch samples including a variety of different structures with variations in the amylopectin branching pattern, amylose content and phosphate content, enzymatically modified starches and glycogen were included. Using this technique, different important structures, including amylose content and branching degrees could be differentiated in a high throughput fashion. The screening method was validated using transgenic barley grain analysed during development and subjected to germination. Typically, extreme branching or linearity were detected less than normal starch structures. The method offers the potential for rapidly analysing resistant and slowly digested dietary starches. PMID:27468930

  18. High throughput screening of starch structures using carbohydrate microarrays

    PubMed Central

    Tanackovic, Vanja; Rydahl, Maja Gro; Pedersen, Henriette Lodberg; Motawia, Mohammed Saddik; Shaik, Shahnoor Sultana; Mikkelsen, Maria Dalgaard; Krunic, Susanne Langgaard; Fangel, Jonatan Ulrik; Willats, William George Tycho; Blennow, Andreas

    2016-01-01

    In this study we introduce the starch-recognising carbohydrate binding module family 20 (CBM20) from Aspergillus niger for screening biological variations in starch molecular structure using high throughput carbohydrate microarray technology. Defined linear, branched and phosphorylated maltooligosaccharides, pure starch samples including a variety of different structures with variations in the amylopectin branching pattern, amylose content and phosphate content, enzymatically modified starches and glycogen were included. Using this technique, different important structures, including amylose content and branching degrees could be differentiated in a high throughput fashion. The screening method was validated using transgenic barley grain analysed during development and subjected to germination. Typically, extreme branching or linearity were detected less than normal starch structures. The method offers the potential for rapidly analysing resistant and slowly digested dietary starches. PMID:27468930

  19. Portable thermo-powered high-throughput visual electrochemiluminescence sensor.

    PubMed

    Hao, Nan; Xiong, Meng; Zhang, Jia-dong; Xu, Jing-Juan; Chen, Hong-Yuan

    2013-12-17

    This paper describes a portable thermo-powered high-throughput visual electrochemiluminescence (ECL) sensor for the first time. This sensor is composed of a tiny power supply device based on thermal-electrical conversion and a facile prepared array electrode. The ECL detection could be conducted with thermo-power, which is easily accessible. For example, hot water, a bonfire, or a lighted candle enables the detection to be conducted. And the assay can be directly monitored by the naked eye semiquantitatively or smart phones quantitatively. Combined with transparent electrode and array microreactors, a portable high-throughput sensor was achieved. The portable device, avoiding the use of an electrochemical workstation to generate potential and a photomultiplier tube to receive the signal, is not only a valuable addition for traditional methods but also a suitable device for field operation or point-of-care testing. PMID:24215560

  20. A high-throughput microRNA expression profiling system.

    PubMed

    Guo, Yanwen; Mastriano, Stephen; Lu, Jun

    2014-01-01

    As small noncoding RNAs, microRNAs (miRNAs) regulate diverse biological functions, including physiological and pathological processes. The expression and deregulation of miRNA levels contain rich information with diagnostic and prognostic relevance and can reflect pharmacological responses. The increasing interest in miRNA-related research demands global miRNA expression profiling on large numbers of samples. We describe here a robust protocol that supports high-throughput sample labeling and detection on hundreds of samples simultaneously. This method employs 96-well-based miRNA capturing from total RNA samples and on-site biochemical reactions, coupled with bead-based detection in 96-well format for hundreds of miRNAs per sample. With low-cost, high-throughput, high detection specificity, and flexibility to profile both small and large numbers of samples, this protocol can be adapted in a wide range of laboratory settings. PMID:25030917

  1. High-throughput screening to identify inhibitors of lysine demethylases

    PubMed Central

    Gale, Molly; Yan, Qin

    2015-01-01

    Lysine demethylases (KDMs) are epigenetic regulators whose dysfunction is implicated in the pathology of many human diseases including various types of cancer, inflammation and X-linked intellectual disability. Particular demethylases have been identified as promising therapeutic targets, and tremendous efforts are being devoted toward developing suitable small-molecule inhibitors for clinical and research use. Several high-throughput screening strategies have been developed to screen for small-molecule inhibitors of KDMs, each with advantages and disadvantages in terms of time, cost, effort, reliability and sensitivity. In this Special Report, we review and evaluate the high-throughput screening methods utilized for discovery of novel small-molecule KDM inhibitors. PMID:25687466

  2. A high-throughput label-free nanoparticle analyser

    NASA Astrophysics Data System (ADS)

    Fraikin, Jean-Luc; Teesalu, Tambet; McKenney, Christopher M.; Ruoslahti, Erkki; Cleland, Andrew N.

    2011-05-01

    Synthetic nanoparticles and genetically modified viruses are used in a range of applications, but high-throughput analytical tools for the physical characterization of these objects are needed. Here we present a microfluidic analyser that detects individual nanoparticles and characterizes complex, unlabelled nanoparticle suspensions. We demonstrate the detection, concentration analysis and sizing of individual synthetic nanoparticles in a multicomponent mixture with sufficient throughput to analyse 500,000 particles per second. We also report the rapid size and titre analysis of unlabelled bacteriophage T7 in both salt solution and mouse blood plasma, using just ~1 × 10-6 l of analyte. Unexpectedly, in the native blood plasma we discover a large background of naturally occurring nanoparticles with a power-law size distribution. The high-throughput detection capability, scalable fabrication and simple electronics of this instrument make it well suited for diverse applications.

  3. High-throughput patterning of photonic structures with tunable periodicity

    PubMed Central

    Kempa, Thomas J.; Bediako, D. Kwabena; Kim, Sun-Kyung; Park, Hong-Gyu; Nocera, Daniel G.

    2015-01-01

    A patterning method termed “RIPPLE” (reactive interface patterning promoted by lithographic electrochemistry) is applied to the fabrication of arrays of dielectric and metallic optical elements. This method uses cyclic voltammetry to impart patterns onto the working electrode of a standard three-electrode electrochemical setup. Using this technique and a template stripping process, periodic arrays of Ag circular Bragg gratings are patterned in a high-throughput fashion over large substrate areas. By varying the scan rate of the cyclically applied voltage ramps, the periodicity of the gratings can be tuned in situ over micrometer and submicrometer length scales. Characterization of the periodic arrays of periodic gratings identified point-like and annular scattering modes at different planes above the structured surface. Facile, reliable, and rapid patterning techniques like RIPPLE may enable the high-throughput and low-cost fabrication of photonic elements and metasurfaces for energy conversion and sensing applications. PMID:25870280

  4. A high-throughput multiplex method adapted for GMO detection.

    PubMed

    Chaouachi, Maher; Chupeau, Gaëlle; Berard, Aurélie; McKhann, Heather; Romaniuk, Marcel; Giancola, Sandra; Laval, Valérie; Bertheau, Yves; Brunel, Dominique

    2008-12-24

    A high-throughput multiplex assay for the detection of genetically modified organisms (GMO) was developed on the basis of the existing SNPlex method designed for SNP genotyping. This SNPlex assay allows the simultaneous detection of up to 48 short DNA sequences (approximately 70 bp; "signature sequences") from taxa endogenous reference genes, from GMO constructions, screening targets, construct-specific, and event-specific targets, and finally from donor organisms. This assay avoids certain shortcomings of multiplex PCR-based methods already in widespread use for GMO detection. The assay demonstrated high specificity and sensitivity. The results suggest that this assay is reliable, flexible, and cost- and time-effective for high-throughput GMO detection.

  5. High-throughput theoretical design of lithium battery materials

    NASA Astrophysics Data System (ADS)

    Shi-Gang, Ling; Jian, Gao; Rui-Juan, Xiao; Li-Quan, Chen

    2016-01-01

    The rapid evolution of high-throughput theoretical design schemes to discover new lithium battery materials is reviewed, including high-capacity cathodes, low-strain cathodes, anodes, solid state electrolytes, and electrolyte additives. With the development of efficient theoretical methods and inexpensive computers, high-throughput theoretical calculations have played an increasingly important role in the discovery of new materials. With the help of automatic simulation flow, many types of materials can be screened, optimized and designed from a structural database according to specific search criteria. In advanced cell technology, new materials for next generation lithium batteries are of great significance to achieve performance, and some representative criteria are: higher energy density, better safety, and faster charge/discharge speed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11234013 and 51172274) and the National High Technology Research and Development Program of China (Grant No. 2015AA034201).

  6. A combined within-host and between-hosts modelling framework for the evolution of resistance to antimalarial drugs

    PubMed Central

    2016-01-01

    The spread of drug resistance represents a significant challenge to many disease control efforts. The evolution of resistance is a complex process influenced by transmission dynamics between hosts as well as infection dynamics within these hosts. This study aims to investigate how these two processes combine to impact the evolution of resistance in malaria parasites. We introduce a stochastic modelling framework combining an epidemiological model of Plasmodium transmission and an explicit within-human infection model for two competing strains. Immunity, treatment and resistance costs are included in the within-host model. We show that the spread of resistance is generally less likely in areas of intense transmission, and therefore of increased competition between strains, an effect exacerbated when costs of resistance are higher. We also illustrate how treatment influences the spread of resistance, with a trade-off between slowing resistance and curbing disease incidence. We show that treatment coverage has a stronger impact on disease prevalence, whereas treatment efficacy primarily affects resistance spread, suggesting that coverage should constitute the primary focus of control efforts. Finally, we illustrate the importance of feedbacks between modelling scales. Overall, our results underline the importance of concomitantly modelling the evolution of resistance within and between hosts. PMID:27075004

  7. A combined within-host and between-hosts modelling framework for the evolution of resistance to antimalarial drugs.

    PubMed

    Legros, Mathieu; Bonhoeffer, Sebastian

    2016-04-01

    The spread of drug resistance represents a significant challenge to many disease control efforts. The evolution of resistance is a complex process influenced by transmission dynamics between hosts as well as infection dynamics within these hosts. This study aims to investigate how these two processes combine to impact the evolution of resistance in malaria parasites. We introduce a stochastic modelling framework combining an epidemiological model of Plasmodium transmission and an explicit within-human infection model for two competing strains. Immunity, treatment and resistance costs are included in the within-host model. We show that the spread of resistance is generally less likely in areas of intense transmission, and therefore of increased competition between strains, an effect exacerbated when costs of resistance are higher. We also illustrate how treatment influences the spread of resistance, with a trade-off between slowing resistance and curbing disease incidence. We show that treatment coverage has a stronger impact on disease prevalence, whereas treatment efficacy primarily affects resistance spread, suggesting that coverage should constitute the primary focus of control efforts. Finally, we illustrate the importance of feedbacks between modelling scales. Overall, our results underline the importance of concomitantly modelling the evolution of resistance within and between hosts. PMID:27075004

  8. Statistical Methods for Analysis of High-Throughput RNA Interference Screens

    PubMed Central

    Birmingham, Amanda; Selfors, Laura M.; Forster, Thorsten; Wrobel, David; Kennedy, Caleb J.; Shanks, Emma; Santoyo-Lopez, Javier; Dunican, Dara J.; Long, Aideen; Kelleher, Dermot; Smith, Queta; Beijersbergen, Roderick L.; Ghazal, Peter; Shamu, Caroline E.

    2009-01-01

    RNA interference (RNAi) has become a powerful technique for reverse genetics and drug discovery and, in both of these areas, large-scale high-throughput RNAi screens are commonly performed. The statistical techniques used to analyze these screens are frequently borrowed directly from small-molecule screening; however small-molecule and RNAi data characteristics differ in meaningful ways. We examine the similarities and differences between RNAi and small-molecule screens, highlighting particular characteristics of RNAi screen data that must be addressed during analysis. Additionally, we provide guidance on selection of analysis techniques in the context of a sample workflow. PMID:19644458

  9. Identification of Novel IGF1R Kinase Inhibitors by Molecular Modeling and High-Throughput Screening

    PubMed Central

    Moriev, R.; Vasylchenko, O.; Platonov, M.; Grygorenko, O.; Volkova, K.; Zozulya, S.

    2013-01-01

    The aim of this study was to identify small molecule compounds that inhibit the kinase activity of the IGF1 receptor and represent novel chemical scaffolds, which can be potentially exploited to develop drug candidates that are superior to the existing experimental anti-IGF1R therapeuticals. To this end, targeted compound libraries were produced by virtual screening using molecular modeling and docking strategies, as well as the ligand-based pharmacophore model. High-throughput screening of the resulting compound sets in a biochemical kinase inhibition assay allowed us to identify several novel chemotypes that represent attractive starting points for the development of advanced IGF1R inhibitory compounds. PMID:23819040

  10. Transfection microarrays for high-throughput phenotypic screening of genes involved in cell migration.

    PubMed

    Onuki-Nagasaki, Reiko; Nagasaki, Akira; Hakamada, Kazumi; Uyeda, Taro Q P; Fujita, Satoshi; Miyake, Masato; Miyake, Jun

    2010-01-01

    Cell migration is important in several biological phenomena, such as cancer metastasis. Therefore, the identification of genes involved in cell migration might facilitate the discovery of antimetastatic drugs. However, screening of genes by the current methods can be complicated by factors related to cell stimulation, for example, abolition of contact inhibition and the release inflammatory cytokines from wounded cells during examinations of wound healing in vitro. To overcome these problems and identify genes involved in cell migration, in this chapter we describe the use of transfection microarrays for high-throughput phenotypic screening. PMID:20387151

  11. High-throughput screening-driven lead discovery: meeting the challenges of finding new therapeutics.

    PubMed

    Posner, Bruce A

    2005-07-01

    The pharmaceutical industry faces a number of challenges that have cumulatively led to a decline in productivity, despite increasing levels of investment in research and development. It is in this context that some researchers and business analysts are questioning the value of the high-throughput screening (HTS) paradigm for the discovery of new therapeutics. While this criticism may be premature, significant changes are occurring in HTS-driven lead discovery to address the failure of drug candidates in the clinic. This article highlights some of these changes and their potential impact.

  12. Automated sample preparation and LC-MS for high-throughput ADME quantification.

    PubMed

    O'Connor, Desmond

    2002-01-01

    Bioanalytical groups in the pharmaceutical industry provide quantitative data to support all stages of drug discovery. The increased use of 96-well plates and robotic liquid handling systems, the availability of robust triple quadruple mass spectrometers, and developments in chromatographic and samples preparation techniques, have all increased the rate at which this data can be generated. This review describes currently used methods and emerging technologies for automation of high-throughput quantitative bioanalysis. The focus is on recent applications of sample preparation and chromatography techniques compatible with detection by triple quadruple mass spectrometers.

  13. NanoLuc Luciferase – A Multifunctional Tool for High Throughput Antibody Screening

    PubMed Central

    Boute, Nicolas; Lowe, Peter; Berger, Sven; Malissard, Martine; Robert, Alain; Tesar, Michael

    2016-01-01

    Based on the recent development of NanoLuc luciferase (Nluc), a small (19 kDa), highly stable, ATP independent, bioluminescent protein, an extremely robust and ultra high sensitivity screening system has been developed whereby primary hits of therapeutic antibodies and antibody fragments could be characterized and quantified without purification. This system is very versatile allowing cellular and solid phase ELISA but also homogeneous BRET based screening assays, relative affinity determinations with competition ELISA and direct Western blotting. The new Nluc protein fusion represents a “swiss army knife solution” for today and future high throughput antibody drug screenings. PMID:26924984

  14. High Throughput siRNA Screening Using Reverse Transfection.

    PubMed

    von Schantz, Carina; Saarela, Jani

    2016-01-01

    RNA interference (RNAi) is a commonly used technique to knockdown gene function. Here, we describe a high throughput screening method for siRNA mediated gene silencing of the breast cancer cell line MDA-MB-231 using reverse transfection. Furthermore, we describe the setup for two separate methods for detecting viable and dead cells using either homogenous assays or image-based analysis. PMID:27581282

  15. A fully automated robotic system for high throughput fermentation.

    PubMed

    Zimmermann, Hartmut F; Rieth, Jochen

    2007-03-01

    High throughput robotic systems have been used since the 1990s to carry out biochemical assays in microtiter plates. However, before the application of such systems in industrial fermentation process development, some important specific demands should be taken into account. These are sufficient oxygen supply, optimal growth temperature, minimized sample evaporation, avoidance of contaminations, and simple but reliable process monitoring. A fully automated solution where all these aspects have been taken into account is presented.

  16. High-throughput evaluation of synthetic metabolic pathways

    PubMed Central

    Klesmith, Justin R.; Whitehead, Timothy A.

    2016-01-01

    A central challenge in the field of metabolic engineering is the efficient identification of a metabolic pathway genotype that maximizes specific productivity over a robust range of process conditions. Here we review current methods for optimizing specific productivity of metabolic pathways in living cells. New tools for library generation, computational analysis of pathway sequence-flux space, and high-throughput screening and selection techniques are discussed. PMID:27453919

  17. High-Throughput Intracellular Antimicrobial Susceptibility Testing of Legionella pneumophila

    PubMed Central

    Chiaraviglio, Lucius

    2015-01-01

    Legionella pneumophila is a Gram-negative opportunistic human pathogen that causes a severe pneumonia known as Legionnaires' disease. Notably, in the human host, the organism is believed to replicate solely within an intracellular compartment, predominantly within pulmonary macrophages. Consequently, successful therapy is predicated on antimicrobials penetrating into this intracellular growth niche. However, standard antimicrobial susceptibility testing methods test solely for extracellular growth inhibition. Here, we make use of a high-throughput assay to characterize intracellular growth inhibition activity of known antimicrobials. For select antimicrobials, high-resolution dose-response analysis was then performed to characterize and compare activity levels in both macrophage infection and axenic growth assays. Results support the superiority of several classes of nonpolar antimicrobials in abrogating intracellular growth. Importantly, our assay results show excellent correlations with prior clinical observations of antimicrobial efficacy. Furthermore, we also show the applicability of high-throughput automation to two- and three-dimensional synergy testing. High-resolution isocontour isobolograms provide in vitro support for specific combination antimicrobial therapy. Taken together, findings suggest that high-throughput screening technology may be successfully applied to identify and characterize antimicrobials that target bacterial pathogens that make use of an intracellular growth niche. PMID:26392509

  18. THINK Back: KNowledge-based Interpretation of High Throughput data.

    PubMed

    Farfán, Fernando; Ma, Jun; Sartor, Maureen A; Michailidis, George; Jagadish, Hosagrahar V

    2012-01-01

    Results of high throughput experiments can be challenging to interpret. Current approaches have relied on bulk processing the set of expression levels, in conjunction with easily obtained external evidence, such as co-occurrence. While such techniques can be used to reason probabilistically, they are not designed to shed light on what any individual gene, or a network of genes acting together, may be doing. Our belief is that today we have the information extraction ability and the computational power to perform more sophisticated analyses that consider the individual situation of each gene. The use of such techniques should lead to qualitatively superior results. The specific aim of this project is to develop computational techniques to generate a small number of biologically meaningful hypotheses based on observed results from high throughput microarray experiments, gene sequences, and next-generation sequences. Through the use of relevant known biomedical knowledge, as represented in published literature and public databases, we can generate meaningful hypotheses that will aide biologists to interpret their experimental data. We are currently developing novel approaches that exploit the rich information encapsulated in biological pathway graphs. Our methods perform a thorough and rigorous analysis of biological pathways, using complex factors such as the topology of the pathway graph and the frequency in which genes appear on different pathways, to provide more meaningful hypotheses to describe the biological phenomena captured by high throughput experiments, when compared to other existing methods that only consider partial information captured by biological pathways. PMID:22536867

  19. THINK Back: KNowledge-based Interpretation of High Throughput data

    PubMed Central

    2012-01-01

    Results of high throughput experiments can be challenging to interpret. Current approaches have relied on bulk processing the set of expression levels, in conjunction with easily obtained external evidence, such as co-occurrence. While such techniques can be used to reason probabilistically, they are not designed to shed light on what any individual gene, or a network of genes acting together, may be doing. Our belief is that today we have the information extraction ability and the computational power to perform more sophisticated analyses that consider the individual situation of each gene. The use of such techniques should lead to qualitatively superior results. The specific aim of this project is to develop computational techniques to generate a small number of biologically meaningful hypotheses based on observed results from high throughput microarray experiments, gene sequences, and next-generation sequences. Through the use of relevant known biomedical knowledge, as represented in published literature and public databases, we can generate meaningful hypotheses that will aide biologists to interpret their experimental data. We are currently developing novel approaches that exploit the rich information encapsulated in biological pathway graphs. Our methods perform a thorough and rigorous analysis of biological pathways, using complex factors such as the topology of the pathway graph and the frequency in which genes appear on different pathways, to provide more meaningful hypotheses to describe the biological phenomena captured by high throughput experiments, when compared to other existing methods that only consider partial information captured by biological pathways. PMID:22536867

  20. Promises and Pitfalls of High-Throughput Biological Assays.

    PubMed

    Finak, Greg; Gottardo, Raphael

    2016-01-01

    This chapter discusses some of the pitfalls encountered when performing biomedical research involving high-throughput "omics" data and presents some strategies and guidelines that researchers should follow when undertaking such studies. We discuss common errors in experimental design and data analysis that lead to irreproducible and non-replicable research and provide some guidelines to avoid these common mistakes so that researchers may have confidence in study outcomes, even if the results are negative. We discuss the importance of ranking and prespecifying hypotheses, performing power analysis, careful experimental design, and preplanning of statistical analyses in order to avoid the "fishing expedition" data analysis strategy, which is doomed to fail. The impact of multiple testing on false-positive rates is discussed, particularly in the context of the analysis of high-throughput data, and methods to correct for it are presented, as well as approaches to detect and correct for experimental biases and batch effects, which often plague high-throughput assays. We highlight the importance of sharing data and analysis code to facilitate reproducibility and present tools and software that are appropriate for this purpose. PMID:27115636

  1. THINK Back: KNowledge-based Interpretation of High Throughput data.

    PubMed

    Farfán, Fernando; Ma, Jun; Sartor, Maureen A; Michailidis, George; Jagadish, Hosagrahar V

    2012-03-13

    Results of high throughput experiments can be challenging to interpret. Current approaches have relied on bulk processing the set of expression levels, in conjunction with easily obtained external evidence, such as co-occurrence. While such techniques can be used to reason probabilistically, they are not designed to shed light on what any individual gene, or a network of genes acting together, may be doing. Our belief is that today we have the information extraction ability and the computational power to perform more sophisticated analyses that consider the individual situation of each gene. The use of such techniques should lead to qualitatively superior results. The specific aim of this project is to develop computational techniques to generate a small number of biologically meaningful hypotheses based on observed results from high throughput microarray experiments, gene sequences, and next-generation sequences. Through the use of relevant known biomedical knowledge, as represented in published literature and public databases, we can generate meaningful hypotheses that will aide biologists to interpret their experimental data. We are currently developing novel approaches that exploit the rich information encapsulated in biological pathway graphs. Our methods perform a thorough and rigorous analysis of biological pathways, using complex factors such as the topology of the pathway graph and the frequency in which genes appear on different pathways, to provide more meaningful hypotheses to describe the biological phenomena captured by high throughput experiments, when compared to other existing methods that only consider partial information captured by biological pathways.

  2. NCBI GEO: archive for high-throughput functional genomic data.

    PubMed

    Barrett, Tanya; Troup, Dennis B; Wilhite, Stephen E; Ledoux, Pierre; Rudnev, Dmitry; Evangelista, Carlos; Kim, Irene F; Soboleva, Alexandra; Tomashevsky, Maxim; Marshall, Kimberly A; Phillippy, Katherine H; Sherman, Patti M; Muertter, Rolf N; Edgar, Ron

    2009-01-01

    The Gene Expression Omnibus (GEO) at the National Center for Biotechnology Information (NCBI) is the largest public repository for high-throughput gene expression data. Additionally, GEO hosts other categories of high-throughput functional genomic data, including those that examine genome copy number variations, chromatin structure, methylation status and transcription factor binding. These data are generated by the research community using high-throughput technologies like microarrays and, more recently, next-generation sequencing. The database has a flexible infrastructure that can capture fully annotated raw and processed data, enabling compliance with major community-derived scientific reporting standards such as 'Minimum Information About a Microarray Experiment' (MIAME). In addition to serving as a centralized data storage hub, GEO offers many tools and features that allow users to effectively explore, analyze and download expression data from both gene-centric and experiment-centric perspectives. This article summarizes the GEO repository structure, content and operating procedures, as well as recently introduced data mining features. GEO is freely accessible at http://www.ncbi.nlm.nih.gov/geo/.

  3. High-Throughput Optical Sensing Immunoassays on Smartphone.

    PubMed

    Wang, Li-Ju; Sun, Rongrong; Vasile, Tina; Chang, Yu-Chung; Li, Lei

    2016-08-16

    We present an optical sensing platform on a smartphone for high-throughput screening immunoassays. For the first time, a designed microprism array is utilized to achieve a one-time screening of 64 samples. To demonstrate the capability and the reliability of this optical sensing platform on smartphone, human interleukin 6 (IL-6) protein and six types of plant viruses are immunoassayed. The ability of quantification is shown by a sigmoidal dose-response curve fitting to analyze IL-6 protein. The accuracy in measuring the concentrations of IL-6 protein achieves 99.1%. On the other hand, to validate on-field immunoassays by our device, a total of 1030 samples are assayed using three immunoassay methods to detect six types of plant viruses. The accuracy is up to 96.2-99.9%; in addition, there is a high degree of agreement with lab instruments. The total cost for this high-throughput optical screening platform is ∼$50 USD. The reading time is only 2 s for 64 samples. The size is just as big as a portable hard drive. Our optical sensing platform on the smartphone offers a route toward in situ high-throughput screening immunoassays for viruses, pathogens, biomarkers, and toxins by decentralizing laboratory tests. With this mobile point-of-care optical platform, the spread of disease can be timely stopped within a very short turnaround time. PMID:27434250

  4. High throughput and miniaturised systems for biodegradability assessments.

    PubMed

    Cregut, Mickael; Jouanneau, Sulivan; Brillet, François; Durand, Marie-José; Sweetlove, Cyril; Chenèble, Jean-Charles; L'Haridon, Jacques; Thouand, Gérald

    2014-01-01

    The society demands safer products with a better ecological profile. Regulatory criteria have been developed to prevent risks for human health and the environment, for example, within the framework of the European regulation REACH (Regulation (EC) No 1907, 2006). This has driven industry to consider the development of high throughput screening methodologies for assessing chemical biodegradability. These new screening methodologies must be scalable for miniaturisation, reproducible and as reliable as existing procedures for enhanced biodegradability assessment. Here, we evaluate two alternative systems that can be scaled for high throughput screening and conveniently miniaturised to limit costs in comparison with traditional testing. These systems are based on two dyes as follows: an invasive fluorescent dyes that serves as a cellular activity marker (a resazurin-like dye reagent) and a noninvasive fluorescent oxygen optosensor dye (an optical sensor).