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Sample records for anti-malarial drug sensitivity

  1. Co-treatment with the anti-malarial drugs mefloquine and primaquine highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition.

    PubMed

    Kim, Ju-Hwa; Choi, Ae-Ran; Kim, Yong Kee; Yoon, Sungpil

    2013-11-22

    The purpose of this study was to identify conditions that will increase the sensitivity of resistant cancer cells to anti-mitotic drugs. Currently, atovaquine (ATO), chloroquine (CHL), primaquine (PRI), mefloquine (MEF), artesunate (ART), and doxycycline (DOY) are the most commonly used anti-malarial drugs. Herein, we tested whether anti-malarial drugs can sensitize drug-resistant KBV20C cancer cells. None of the six tested anti-malarial drugs was found to better sensitize the drug-resistant cells compared to the sensitive KB cells. With an exception of DOY, all other anti-malarial drugs tested could sensitize both KB and KBV20C cells to a similar extent, suggesting that anti-malarial drugs could be used for sensitive as well as resistant cancer cells. Furthermore, we examined the effects of anti-malarial drugs in combination with an antimitotic drug, vinblastine (VIN) on the sensitisation of resistant KBV20C cells. Using viability assay, microscopic observation, assessment of cleaved PARP, and Hoechst staining, we identified that two anti-malarial drugs, PRI and MEF, highly sensitized KBV20C-resistant cells to VIN treatment. Moreover, PRI- or MEF-induced sensitisation was not observed in VIN-treated sensitive KB parent cells, suggesting that the observed effect is specific to resistant cancer cells. We demonstrated that the PRI and MEF sensitisation mechanism mainly depends on the inhibition of p-glycoprotein (P-gp). Our findings may contribute to the development of anti-malarial drug-based combination therapies for patients resistant to anti-mitotic drugs.

  2. 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

  3. Artemisinin anti-malarial drugs in China.

    PubMed

    Guo, Zongru

    2016-03-01

    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.

  4. 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

  5. Substandard anti-malarial drugs in Burkina Faso.

    PubMed

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

    2008-05-27

    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. 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. 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. 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 and substantially more costly

  6. Anti-malarial effect of semi-synthetic drug amitozyn.

    PubMed

    Tcherniuk, Sergey O; Chesnokova, Olga; Oleinikov, Irina V; Potopalsky, Anatoly I; Oleinikov, Andrew V

    2015-10-29

    Malaria caused by Plasmodium falciparum is the most virulent form of malaria, leading to approximately a half million deaths per year. Chemotherapy continues to be a key approach in malaria prevention and treatment. Due to widespread parasite drug resistance, identification and development of new anti-malarial compounds remains an important task of malarial parasitology. The semi-synthetic drug amitozyn, obtained through alkylation of major celandine (Chelidonium majus) alkaloids with N,N'N'-triethylenethiophosphoramide (ThioTEPA), is a widely used Eastern European folk medicine for the treatment of various tumours. However, its anti-malarial effect has never been studied. The anti-malarial effects of amitozyn alone and in combination with chloroquine, pyrimethamine and artemisinin on the blood stages of P. falciparum were analysed. The cytostatic effects of amitozyn on parasites and various cancerous and non-cancerous human cells were compared and their toxic effects on unparasitized human red blood cells were analysed. Obtained results demonstrate that amitozyn effectively inhibits the growth of blood-stage parasites with IC50 9.6 ± 2, 11.3 ± 2.8 and 10.8 ± 1.8 μg/mL using CS2, 3G8 and NF54 parasite lines, respectively. The median IC50 for 14 tested human cell lines was 33-152 μg/mL. Treatment of uninfected red blood cells with a high dose of amitozyn (500 μg/mL) did not change cell morphology, demonstrating its non-toxicity for erythrocytes. The synergistic impact of the amitozyn/chloroquine combination was observed at growth inhibition levels of 10-80 %, while demonstrating a nearly additive effect at a growth inhibition level of 90 %. The combination of amitozyn with pyrimethamine has a synergistic effect at growth inhibition levels of 10-70 % and a nearly additive effect at a growth inhibition level of 90 %. The synergistic anti-malarial effect of the amitozyn/artemisinin combination was observed at growth inhibition levels of 10-40 % and a nearly

  7. Ex vivo anti-malarial drugs sensitivity profile of Plasmodium falciparum field isolates from Burkina Faso five years after the national policy change

    PubMed Central

    2014-01-01

    Background The recent reports on the decreasing susceptibility of Plasmodium falciparum to artemisinin derivatives along the Thailand and Myanmar border are worrying. Indeed it may spread to India and then Africa, repeating the same pattern observed for chloroquine resistance. Therefore, it is essential to start monitoring P. falciparum sensitivity to artemisinin derivatives and its partner drugs in Africa. Efficacy of AL and ASAQ were tested by carrying out an in vivo drug efficacy test, with an ex vivo study against six anti-malarial drugs nested into it. Results of the latter are reported here. Methods Plasmodium falciparum ex-vivo susceptibility to chloroquine (CQ), quinine (Q), lumefantrine (Lum), monodesethylamodiaquine (MDA), piperaquine (PPQ) and dihydroartemisinin (DHA) was investigated in children (6 months – 15 years) with a parasitaemia of at least ≥4,000/μl. The modified isotopic microtest technique was used. The results of cellular proliferation were analysed using ICEstimator software to determine the 50% inhibitory concentration (IC50) values. Results DHA was the most potent among the 6 drugs tested, with IC50 values ranging from 0.8 nM to 0.9 nM (Geometric mean IC50 = 0.8 nM; 95% CI [0.8 - 0.9]). High IC50 values ranged between 0.8 nM to 166.1 nM were reported for lumefantrine (Geometric mean IC50 = 25.1 nM; 95% CI [22.4 - 28.2]). MDA and Q IC50s were significantly higher in CQ-resistant than in CQ-sensitive isolates (P = 0.0001). However, the opposite occurred for Lum and DHA (P < 0.001). No difference was observed for PPQ. Conclusion Artemisinin derivatives are still very efficacious in Burkina Faso and DHA-PPQ seems a valuable alternative ACT. The high lumefantrine IC50 found in this study is worrying as it may indicate a decreasing efficacy of one of the first-line treatments. This should be further investigated and monitored over time with large in vivo and ex vivo studies that will include also plasma drug measurements

  8. Ex vivo anti-malarial drugs sensitivity profile of Plasmodium falciparum field isolates from Burkina Faso five years after the national policy change.

    PubMed

    Tinto, Halidou; Bonkian, Léa N; Nana, Louis A; Yerbanga, Isidore; Lingani, Moussa; Kazienga, Adama; Valéa, Innocent; Sorgho, Hermann; Kpoda, Hervé; Guiguemdé, Tinga Robert; Ouédraogo, Jean Bosco; Mens, Petronella F; Schallig, Henk; D'Alessandro, Umberto

    2014-05-31

    The recent reports on the decreasing susceptibility of Plasmodium falciparum to artemisinin derivatives along the Thailand and Myanmar border are worrying. Indeed it may spread to India and then Africa, repeating the same pattern observed for chloroquine resistance. Therefore, it is essential to start monitoring P. falciparum sensitivity to artemisinin derivatives and its partner drugs in Africa. Efficacy of AL and ASAQ were tested by carrying out an in vivo drug efficacy test, with an ex vivo study against six anti-malarial drugs nested into it. Results of the latter are reported here. Plasmodium falciparum ex-vivo susceptibility to chloroquine (CQ), quinine (Q), lumefantrine (Lum), monodesethylamodiaquine (MDA), piperaquine (PPQ) and dihydroartemisinin (DHA) was investigated in children (6 months - 15 years) with a parasitaemia of at least ≥4,000/μl. The modified isotopic microtest technique was used. The results of cellular proliferation were analysed using ICEstimator software to determine the 50% inhibitory concentration (IC50) values. DHA was the most potent among the 6 drugs tested, with IC50 values ranging from 0.8 nM to 0.9 nM (Geometric mean IC50 = 0.8 nM; 95% CI [0.8 - 0.9]). High IC50 values ranged between 0.8 nM to 166.1 nM were reported for lumefantrine (Geometric mean IC50 = 25.1 nM; 95% CI [22.4 - 28.2]). MDA and Q IC50s were significantly higher in CQ-resistant than in CQ-sensitive isolates (P = 0.0001). However, the opposite occurred for Lum and DHA (P < 0.001). No difference was observed for PPQ. Artemisinin derivatives are still very efficacious in Burkina Faso and DHA-PPQ seems a valuable alternative ACT. The high lumefantrine IC50 found in this study is worrying as it may indicate a decreasing efficacy of one of the first-line treatments. This should be further investigated and monitored over time with large in vivo and ex vivo studies that will include also plasma drug measurements.

  9. Temporal changes in Plasmodium falciparum anti-malarial drug sensitivity in vitro and resistance-associated genetic mutations in isolates from Papua New Guinea.

    PubMed

    Koleala, Tamarah; Karl, Stephan; Laman, Moses; Moore, Brioni R; Benjamin, John; Barnadas, Celine; Robinson, Leanne J; Kattenberg, Johanna H; Javati, Sarah; Wong, Rina P M; Rosanas-Urgell, Anna; Betuela, Inoni; Siba, Peter M; Mueller, Ivo; Davis, Timothy M E

    2015-01-28

    mutations. Temporal changes in IC₅₀s for other anti-malarial drugs were inconsistent but susceptibility was preserved. Retention or increases in pfdhfr and pfdhps mutations reflect continued use of sulphadoxine-pyrimethamine in the study area including through paediatric intermittent preventive treatment. The susceptibility of local isolates to lumefantrine may be unrelated to those of other ACT partner drugs. Australian New Zealand Clinical Trials Registry ACTRN12610000913077 .

  10. CRIMALDDI: platform technologies and novel anti-malarial drug targets.

    PubMed

    Vial, Henri; Taramelli, Donatella; Boulton, Ian C; Ward, Steve A; Doerig, Christian; Chibale, Kelly

    2013-11-05

    The Coordination, Rationalization, and Integration of antiMALarial drug Discovery & Development Initiatives (CRIMALDDI) Consortium, funded by the EU Framework Seven Programme, has attempted, through a series of interactive and facilitated workshops, to develop priorities for research to expedite the discovery of new anti-malarials. This paper outlines the recommendations for the development of enabling technologies and the identification of novel targets.Screening systems must be robust, validated, reproducible, and represent human malaria. They also need to be cost-effective. While such systems exist to screen for activity against blood stage Plasmodium falciparum, they are lacking for other Plasmodium spp. and other stages of the parasite's life cycle. Priority needs to be given to developing high-throughput screens that can identify activity against the liver and sexual stages. This in turn requires other enabling technologies to be developed to allow the study of these stages and to allow for the culture of liver cells and the parasite at all stages of its life cycle.As these enabling technologies become available, they will allow novel drug targets to be studied. Currently anti-malarials are mostly targeting the asexual blood stage of the parasite's life cycle. There are many other attractive targets that need to be investigated. The liver stages and the sexual stages will become more important as malaria control moves towards malaria elimination. Sexual development is a process offering multiple targets, even though the mechanisms of differentiation are still not fully understood. However, designing a drug whose effect is not curative but would be used in asymptomatic patients is difficult given current safety thresholds. Compounds active against the liver schizont would have a prophylactic effect and Plasmodium vivax elimination requires effectors against the dormant liver hypnozoites. It may be that drugs to be used in elimination campaigns will also need

  11. Stated preferences for anti-malarial drug characteristics in Zomba, a malaria endemic area of Malawi.

    PubMed

    Medina-Lara, Antonieta; Mujica-Mota, Ruben E; Kunkwenzu, Esthery D; Lalloo, David G

    2014-07-08

    -quartile range) was highest (most responsive) to speed of symptom resolution (0.88, 0.80-0.89) and pruritus risk (0.25, 0.08-0.62). Most adult antimalarial users are willing to use treatments without recommendation from health professional, and may be influenced by price. Future studies should investigate the magnitude of differences in price and treatment attribute sensitivity between adult anti-malarial drug users in rural, peri-urban and urban areas in order to determine optimal price subsidies.

  12. Inclusion of gametocyte parameters in anti-malarial drug efficacy studies: filling a neglected gap needed for malaria elimination.

    PubMed

    Abdul-Ghani, Rashad; Basco, Leonardo K; Beier, John C; Mahdy, Mohammed A K

    2015-10-19

    Standard anti-malarial drug efficacy and drug resistance assessments neglect the gametocyte parameters in their protocols. With the spread of drug resistance and the absence of clinically proven vaccines, the use of gametocytocidal drugs or drug combinations with transmission-blocking activity is a high priority for malaria control and elimination. However, the limited repertoire of gametocytocidal drugs and induction of gametocytogenesis after treatment with certain anti-malarial drugs necessitate both regular monitoring of gametocytocidal activities of anti-malarial drugs in clinical use and the effectiveness of candidate gametocytocidal agents. Therefore, updating current protocols of anti-malarial drug efficacy is needed to reflect the effects of anti-malarial drugs or drug combinations on gametocyte carriage and gametocyte density along with asexual parasite density. Developing protocols of anti-malarial drug efficacy that include gametocyte parameters related to both microscopic and submicroscopic gametocytaemias is important if drugs or drug combinations are to be strategically used in transmission-blocking interventions in the context of malaria elimination. The present piece of opinion highlights the challenges in gametocyte detection and follow-up and discuss the need for including the gametocyte parameter in anti-malarial efficacy studies.

  13. Assessing the quality of anti-malarial drugs from Gabonese pharmacies using the MiniLab®: a field study.

    PubMed

    Visser, Benjamin J; Meerveld-Gerrits, Janneke; Kroon, Daniëlle; Mougoula, Judith; Vingerling, Rieke; Bache, Emmanuel; Boersma, Jimmy; van Vugt, Michèle; Agnandji, Selidji T; Kaur, Harparkash; Grobusch, Martin P

    2015-07-15

    Recent studies alluded to the alarming scale of poor anti-malarial drug quality in malaria-endemic countries, but also illustrated the major geographical gaps in data on anti-malarial drug quality from endemic countries. Data are particularly scarce from Central Africa, although it carries the highest burden of malaria. The aim of this medicine quality field survey was to determine the prevalence of poor-quality anti-malarial drugs in Gabon. A field survey of the quality of anti-malarial drugs in Gabonese pharmacies was conducted using the Global Pharma Health Fund Minilab(®) tests, following the Medicine Quality Assessment Reporting Guidelines. Anti-malarial drugs were purchased randomly from selected pharmacies in Gabon. Semi-quantitative thin-layer chromatography (TLC) and disintegration testing were carried out to measure the concentration of active pharmaceutical ingredients (APIs). The samples failing the TLC test were analysed by high-performance liquid chromatography. Following the collection of anti-malarial drugs, a street survey was conducted to understand where people purchase their anti-malarial drugs. A total of 432 samples were purchased from 41 pharmacies in 11 cities/towns in Gabon. The prevalence of poor-quality anti-malarial drugs was 0.5% (95% CI 0.08-1.84%). Two out of 432 samples failed the MiniLab(®) semi-quantitative TLC test, of which a suspected artemether-lumefantrine (AL) sample was classified as falsified and one sulfadoxine-pyrimethamine (SP) sample as substandard. High performance liquid chromatography with ultraviolet photo diode array detection analysis confirmed the absence of APIs in the AL sample, and showed that the SP sample did contain the stated APIs but the amount was half the stated dose. Of the people interviewed, 92% (187/203) purchased their anti-malarial drugs at a pharmacy. Using the GPHF Minilab(®), the prevalence of poor-quality anti-malarial drugs is far lower than anticipated. The findings emphasize the need for

  14. Pharmacological considerations in the design of anti-malarial drug combination therapies – is matching half-lives enough?

    PubMed Central

    2014-01-01

    Anti-malarial drugs are now mainly deployed as combination therapy (CT), primarily as a mechanism to prevent or slow the spread of resistance. This strategy is justified by mathematical arguments that generally assume that drug ‘resistance’ is a binary all-or-nothing genetic trait. Herein, a pharmacological, rather than a purely genetic, approach is used to investigate resistance and it is argued that this provides additional insight into the design principles of anti-malarial CTs. It is usually suggested that half-lives of constituent drugs in a CT be matched: it appears more important that their post-treatment anti-malarial activity profiles be matched and strategies identified that may achieve this. In particular, the considerable variation in pharmacological parameters noted in both human and parasites populations may compromise this matching and it is, therefore, essential to accurately quantify the population pharmacokinetics of the drugs in the CTs. Increasing drug dosages will likely follow a law of diminishing returns in efficacy, i.e. a certain increase in dose will not necessarily lead to the same percent increase in efficacy. This may allow individual drug dosages to be lowered without proportional decrease in efficacy, reducing any potential toxicity, and allowing the other drug(s) in the CT to compensate for this reduced dosage; this is a dangerous strategy which is discussed further. Finally, pharmacokinetic and pharmacodynamic drug interactions and the role of resistance mechanisms are discussed. This approach generated an idealized target product profile (TPP) for anti-malarial CTs. There is a restricted pipeline of anti-malarial drugs but awareness of pharmacological design principles during the development stages could optimize CT design pre-deployment. This may help prevent changes in drug dosages and/or regimen that have previously occurred post-deployment in most current anti-malarial drugs. PMID:24552440

  15. Spread of anti-malarial drug resistance: mathematical model with implications for ACT drug policies.

    PubMed

    Pongtavornpinyo, Wirichada; Yeung, Shunmay; Hastings, Ian M; Dondorp, Arjen M; Day, Nicholas P J; White, Nicholas J

    2008-11-02

    Most malaria-endemic countries are implementing a change in anti-malarial drug policy to artemisinin-based combination therapy (ACT). The impact of different drug choices and implementation strategies is uncertain. Data from many epidemiological studies in different levels of malaria endemicity and in areas with the highest prevalence of drug resistance like borders of Thailand are certainly valuable. Formulating an appropriate dynamic data-driven model is a powerful predictive tool for exploring the impact of these strategies quantitatively. A comprehensive model was constructed incorporating important epidemiological and biological factors of human, mosquito, parasite and treatment. The iterative process of developing the model, identifying data needed, and parameterization has been taken to strongly link the model to the empirical evidence. The model provides quantitative measures of outcomes, such as malaria prevalence/incidence and treatment failure, and illustrates the spread of resistance in low and high transmission settings. The model was used to evaluate different anti-malarial policy options focusing on ACT deployment. The model predicts robustly that in low transmission settings drug resistance spreads faster than in high transmission settings, and treatment failure is the main force driving the spread of drug resistance. In low transmission settings, ACT slows the spread of drug resistance to a partner drug, especially at high coverage rates. This effect decreases exponentially with increasing delay in deploying the ACT and decreasing rates of coverage. In the high transmission settings, however, drug resistance is driven by the proportion of the human population with a residual drug level, which gives resistant parasites some survival advantage. The spread of drug resistance could be slowed down by controlling presumptive drug use and avoiding the use of combination therapies containing drugs with mismatched half-lives, together with reducing malaria

  16. 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

  17. Evaluation of the effect of pyrimethamine, an anti-malarial drug, on HIV-1 replication

    PubMed Central

    Oguariri, Raphael M.; Adelsberger, Joseph W.; Baseler, Michael W.; Imamichi, Tomozumi

    2010-01-01

    Co-infection of human immunodeficiency virus (HIV) with malaria is one of the pandemic problems in Africa and parts of Asia. Here we investigated the impact of PYR and two other clinical anti-malarial drugs (chloroquine [CQ] or artemisinin [ART]) on HIV-1 replication. Peripheral blood mononuclear cells (PBMCs) or MT-2 cells were infected with HIVNL4.3 strain and treated with different concentrations of the anti-malarial drugs. HIV-1 replication was measured using p24 ELISA. We show that 10 μM CQ and ART inhibited HIV-1 replication by 76% and 60% in PBMCs, respectively, but not in MT-2 cells. In contrast, 10 μM PYR enhanced HIV-1 replication in MT-2 cells by >10-fold. A series of molecular mechanism studies revealed that PYR increased intracellular HIV gag proteins without affecting the promoter or the reverse transcriptase activity. The effect of PYR was independent of HTLV-1 produced by MT-2 cells. Of interest, PYR treatment led to S-phase accumulation and increased AZT and d4T antiviral activity by ~4-fold. Taken together, we show that PYR significantly enhances HIV-1 replication by affecting the cellular machinery. Our results could be relevant for the management of malaria and HIV particularly in regions where HIV-1 and malaria epidemics overlap. PMID:20800626

  18. 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

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

    PubMed

    Boulton, Ian C; Nwaka, Solomon; Bathurst, Ian; Lanzer, Michael; Taramelli, Donatella; Vial, Henri; Doerig, Christian; Chibale, Kelly; Ward, Steve A

    2010-07-13

    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.

  20. Assessing anti-malarial drug effects ex vivo using the haemozoin detection assay.

    PubMed

    Rebelo, Maria; Tempera, Carolina; Fernandes, José F; Grobusch, Martin P; Hänscheid, Thomas

    2015-04-01

    In vitro sensitivity assays are crucial to detect and monitor drug resistance. Plasmodium falciparum has developed resistance to almost all anti-malarial drugs. Although different in vitro drug assays are available, some of their inherent characteristics limit their application, especially in the field. A recently developed approach based on the flow cytometric detection of haemozoin (Hz) allowed reagent-free monitoring of parasite maturation and detection of drug effects in culture-adapted parasites. In this study, the set-up, performance and usefulness of this novel assay were investigated under field conditions in Gabon. An existing flow cytometer (Cyflow Blue) was modified on site to detect light depolarization caused by Hz. Blood from malaria patients was incubated for 72 hrs with increasing concentrations of chloroquine, artesunate and artemisinin. The percentage of depolarizing red blood cells (RBC) was used as maturation indicator and measured at 24, 48 and 72 hrs of incubation to determine parasite growth and drug effects. The flow cytometer was easily adapted on site to detect light depolarization caused by Hz. Analysis of ex vivo cultures of parasites, obtained from blood samples of malaria patients, showed four different growth profiles. In 39/46 samples, 50% inhibitory concentrations (IC50) were successfully determined. IC50 values for chloroquine were higher than 200 nM in 70% of the samples, indicating the presence of chloroquine-resistant parasites. For artesunate and artemisinin, IC50 values ranged from 0.9 to 60 nM and from 2.2 nM to 124 nM, respectively, indicating fully sensitive parasites. Flow cytometric detection of Hz allowed the detection of drug effects in blood samples from malaria patients, without using additional reagents or complex protocols. Adjustment of the initial parasitaemia was not required, which greatly simplifies the protocol, although it may lead to different IC50 values. Further investigation of set-up conditions of the

  1. The effect of malaria and anti-malarial drugs on skeletal and cardiac muscles.

    PubMed

    Marrelli, Mauro Toledo; Brotto, Marco

    2016-11-02

    Malaria remains one of the most important infectious diseases in the world, being a significant public health problem associated with poverty and it is one of the main obstacles to the economy of an endemic country. Among the several complications, the effects of malaria seem to target the skeletal muscle system, leading to symptoms, such as muscle aches, muscle contractures, muscle fatigue, muscle pain, and muscle weakness. Malaria cause also parasitic coronary artery occlusion. This article reviews the current knowledge regarding the effect of malaria disease and the anti-malarial drugs on skeletal and cardiac muscles. Research articles and case report publications that addressed aspects that are important for understanding the involvement of malaria parasites and anti-malarial therapies affecting skeletal and cardiac muscles were analysed and their findings summarized. Sequestration of red blood cells, increased levels of serum creatine kinase and reduced muscle content of essential contractile proteins are some of the potential biomarkers of the damage levels of skeletal and cardiac muscles. These biomarkers might be useful for prevention of complications and determining the effectiveness of interventions designed to protect cardiac and skeletal muscles from malaria-induced damage.

  2. Prioritization of anti-malarial hits from nature: chemo-informatic profiling of natural products with in vitro antiplasmodial activities and currently registered anti-malarial drugs.

    PubMed

    Egieyeh, Samuel Ayodele; Syce, James; Malan, Sarel F; Christoffels, Alan

    2016-01-29

    A large number of natural products have shown in vitro antiplasmodial activities. Early identification and prioritization of these natural products with potential for novel mechanism of action, desirable pharmacokinetics and likelihood for development into drugs is advantageous. Chemo-informatic profiling of these natural products were conducted and compared to currently registered anti-malarial drugs (CRAD). Natural products with in vitro antiplasmodial activities (NAA) were compiled from various sources. These natural products were sub-divided into four groups based on inhibitory concentration (IC50). Key molecular descriptors and physicochemical properties were computed for these compounds and analysis of variance used to assess statistical significance amongst the sets of compounds. Molecular similarity analysis, estimation of drug-likeness, in silico pharmacokinetic profiling, and exploration of structure-activity landscape were also carried out on these sets of compounds. A total of 1040 natural products were selected and a total of 13 molecular descriptors were analysed. Significant differences were observed among the sub-groups of NAA and CRAD for at least 11 of the molecular descriptors, including number of hydrogen bond donors and acceptors, molecular weight, polar and hydrophobic surface areas, chiral centres, oxygen and nitrogen atoms, and shape index. The remaining molecular descriptors, including clogP, number of rotatable bonds and number of aromatic rings, did not show any significant difference when comparing the two compound sets. Molecular similarity and chemical space analysis identified natural products that were structurally diverse from CRAD. Prediction of the pharmacokinetic properties and drug-likeness of these natural products identified over 50% with desirable drug-like properties. Nearly 70% of all natural products were identified as potentially promiscuous compounds. Structure-activity landscape analysis highlighted compound pairs that

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

    PubMed

    Quashie, Neils B; Duah, Nancy O; Abuaku, Benjamin; Quaye, Lydia; Ayanful-Torgby, Ruth; Akwoviah, George A; Kweku, Margaret; Johnson, Jacob D; Lucchi, Naomi W; Udhayakumar, Venkatachalam; Duplessis, Christopher; Kronmann, Karl C; Koram, Kwadwo A

    2013-12-17

    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. 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. 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, significant elevation of

  4. The biological and clinical activity of anti-malarial drugs in autoimmune disorders.

    PubMed

    Taherian, Elham; Rao, Anshul; Malemud, Charles J; Askari, Ali D

    2013-01-01

    Chloroquine and hydroxychloroquine are 4-aminoquinoline compounds commonly employed as anti-malarial drugs. Chloroquine and its synthetic analogue, hydroxychloroquine also belong to the disease-modifying anti-rheumatic drug class because these drugs are immunosuppressive. The immunosuppressive activity of chloroquine and hydroxychloroquine is likely to account for their capacity to reduce T-cell and B-cell hyperactivity as well as pro-inflammatory cytokine gene expression. This review evaluated experimental and clinical trials results as well as clinical response data relative to the use of chloroquine and/or hydroxychloroquine as first-line medical therapies in systemic lupus erythematosus, rheumatoid arthritis, primary Sjogren's syndrome, the anti-phospholipid syndrome and in the treatment of sarcoidosis. A primary outcomes measure in these clinical trials was the extent to which chloroquine and/or hydroxychloroquine reduced disease progression or exacerbations and/or the use and dosage of corticosteroids. The relative efficacy of chloroquine and hydroxychloroquine in modifying the clinical course of these autoimmune disorders is balanced against evidence that these drugs induce adverse effects which may reduce their use and effectiveness in the therapy of autoimmune disorders.

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

    PubMed

    Mubjer, Reem A; Adeel, Ahmed A; Chance, Michael L; Hassan, Amir A

    2011-08-21

    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). 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. 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. 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. Mutant pfcrtT76 is highly prevalent but it

  6. Repurposing the anti-malarial drug, quinacrine: new anti-colitis properties

    PubMed Central

    Chumanevich, Alexander A.; Witalison, Erin E.; Chaparala, Anusha; Chumanevich, Anastasiya; Nagarkatti, Prakash; Nagarkatti, Mitzi; Hofseth, Lorne J.

    2016-01-01

    Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is associated with an increased risk of colorectal cancer in 8-10 years after disease onset. Current colitis treatment strategies do not offer a cure for the disease, but only treat the symptoms with limited success and dangerous side-effects. Also, there is no preventive treatment for either UC or colorectal cancer. Quinacrine is an anti-malarial drug with versatile use in the treatment of diseases involving inflammatory response such as rheumatoid arthritis and lupus erythematosus. It also has putative anti-cancer effect. Quinacrine's anti-inflammatory, anti-oxidant properties, and anti-tumorigenic properties make it a potential small molecule preventive agent for both UC and associated colorectal cancer. Results There were obvious changes in the CDI, histology, and inflammatory load in quinacrine-treated groups in a dose and time dependent manner in both models of UC, induced by chemical or haptenating agent. Methods We tested quinacrine at two different doses as a colitis treatment agent in two mouse models of UC - the dextran sulfate sodium and oxazolone. The clinical disease index (CDI), histological changes of the colon, levels of inflammatory markers (Cox-2, iNOS, p53) and overall health vitals were evaluated. Conclusions We demonstrate that quinacrine successfully suppresses colitis without any indication of toxicity or side-effects in two mouse models of UC. PMID:27447967

  7. Physicochemical investigation and in vivo activity of anti-malarial drugs co-loaded in Tween 80 niosomes.

    PubMed

    Thakkar, Miloni; S, Brijesh

    2017-09-05

    Drugs used for the treatment and prevention of malaria are often plagued by the problem of development of resistance. This has hampered their therapeutic efficiency and rendered them ineffective for monotherapy. However, if re-packaged and combined properly, many of these neglected anti-malarial drugs can possibly find their way back into the treatment regime. The present study evaluates the use of curcumin (CC) and primaquine (PRI) as an anti-malarial combination, packaged within niosomes, in comparison to their respective monotherapy options. It was observed that in Plasmodium berghei-infected mice, mice treated with a combination of 35 mg/kg of CC along with either 5 mg/kg or 1 mg/kg body weight of PRI demonstrated 100% anti-malarial activity and survivability beyond 20 days. The niosome-based PRI-CC combination therapy provided increased protection and survival rate that was associated with prevention in recrudescence. The findings of the study suggest that niosome-based PRI-CC combination therapy may be a promising approach in the treatment of malaria.

  8. Malaria research and its influence on anti-malarial drug policy in Malawi: a case study.

    PubMed

    Mwendera, Chikondi; de Jager, Christiaan; Longwe, Herbert; Phiri, Kamija; Hongoro, Charles; Mutero, Clifford M

    2016-06-01

    In 1993, Malawi changed its first-line anti-malarial treatment for uncomplicated malaria from chloroquine to sulfadoxine-pyrimethamine (SP), and in 2007, it changed from SP to lumefantrine-artemether. The change in 1993 raised concerns about whether it had occurred timely and whether it had potentially led to early development of Plasmodium falciparum resistance to SP. This case study examined evidence from Malawi in order to assess if the policy changes were justifiable and supported by evidence. A systematic review of documents and published evidence between 1984 and 1993, when chloroquine was the first-line drug, and 1994 and 2007, when SP was the first-line drug, was conducted herein. The review was accompanied with key informant interviews. A total of 1287 publications related to malaria drug policy changes in sub-Saharan Africa were identified. Using the inclusion criteria, four articles from 1984 to 1993 and eight articles from 1994 to 2007 were reviewed. Between 1984 and 1993, three studies reported on chloroquine poor efficacy prompting policy change according to WHO's recommendation. From 1994 to 2007, four studies conducted in the early years of policy change reported a high SP efficacy of above 80%, retaining it as a first-line drug. Unpublished sentinel site studies between 2005 and 2007 showed a reduced efficacy of SP, influencing policy change to lumefantrine-artemether. The views of key informants indicate that the switch from chloroquine to SP was justified based on local evidence despite unavailability of WHO's policy recommendations, while the switch to lumefantrine-artemether was uncomplicated as the country was following the recommendations from WHO. Ample evidence from Malawi influenced and justified the policy changes. Therefore, locally generated evidence is vital for decision making during policy change.

  9. 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

  10. Clinical manifestations of new versus recrudescent malaria infections following anti-malarial drug treatment.

    PubMed

    Shaukat, Ayesha M; Gilliams, Elizabeth A; Kenefic, Leo J; Laurens, Matthew B; Dzinjalamala, Fraction K; Nyirenda, Osward M; Thesing, Phillip C; Jacob, Christopher G; Molyneux, Malcolm E; Taylor, Terrie E; Plowe, Christopher V; Laufer, Miriam K

    2012-06-18

    Distinguishing new from recrudescent infections in post-treatment episodes of malaria is standard in anti-malarial drug efficacy trials. New infections are not considered malaria treatment failures and as a result, the prevention of subsequent episodes of malaria infection is not reported as a study outcome. However, in moderate and high transmission settings, new infections are common and the ability of a short-acting medication to cure an initial infection may be outweighed by its inability to prevent the next imminent infection. The clinical benefit of preventing new infections has never been compared to that of curing the initial infection. Children enrolled in a sulphadoxine-pyrimethamine efficacy study in Blantyre, Malawi from 1998-2004 were prospectively evaluated. Six neutral microsatellites were used to classify new and recrudescent infections in children aged less than 10 years with recurrent malaria infections. Children from the study who did not experience recurrent parasitaemia comprised the baseline group. The odds of fever and anaemia, the rate of haemoglobin recovery and time to recurrence were compared among the groups. Fever and anemia were more common among children with parasitaemia compared to those who remained infection-free throughout the study period. When comparing recrudescent vs. new infections, the incidence of fever was not statistically different. However, children with recrudescent infections had a less robust haematological recovery and also experienced recurrence sooner than those whose infection was classified as new. The results of this study confirm the paramount importance of providing curative treatment for all malaria infections. Although new and recrudescent infections caused febrile illnesses at a similar rate, recurrence due to recrudescent infection did have a worsened haemological outcome than recurrence due to new infections. Local decision-makers should take into account the results of genotyping to distinguish new

  11. SMS for Life: a pilot project to improve anti-malarial drug supply management in rural Tanzania using standard technology

    PubMed Central

    2010-01-01

    restricted availability of anti-malarial drugs or other medicines in rural or under-resourced areas. PMID:20979633

  12. SMS for Life: a pilot project to improve anti-malarial drug supply management in rural Tanzania using standard technology.

    PubMed

    Barrington, Jim; Wereko-Brobby, Olympia; Ward, Peter; Mwafongo, Winfred; Kungulwe, Seif

    2010-10-27

    Maintaining adequate supplies of anti-malarial medicines at the health facility level in rural sub-Saharan Africa is a major barrier to effective management of the disease. Lack of visibility of anti-malarial stock levels at the health facility level is an important contributor to this problem. A 21-week pilot study, 'SMS for Life', was undertaken during 2009-2010 in three districts of rural Tanzania, involving 129 health facilities. Undertaken through a collaborative partnership of public and private institutions, SMS for Life used mobile telephones, SMS messages and electronic mapping technology to facilitate provision of comprehensive and accurate stock counts from all health facilities to each district management team on a weekly basis. The system covered stocks of the four different dosage packs of artemether-lumefantrine (AL) and quinine injectable. Stock count data was provided in 95% of cases, on average. A high response rate (≥ 93%) was maintained throughout the pilot. The error rate for composition of SMS responses averaged 7.5% throughout the study; almost all errors were corrected and messages re-sent. Data accuracy, based on surveillance visits to health facilities, was 94%. District stock reports were accessed on average once a day. The proportion of health facilities with no stock of one or more anti-malarial medicine (i.e. any of the four dosages of AL or quinine injectable) fell from 78% at week 1 to 26% at week 21. In Lindi Rural district, stock-outs were eliminated by week 8 with virtually no stock-outs thereafter. During the study, AL stocks increased by 64% and quinine stock increased 36% across the three districts. The SMS for Life pilot provided visibility of anti-malarial stock levels to support more efficient stock management using simple and widely available SMS technology, via a public-private partnership model that worked highly effectively. The SMS for Life system has the potential to alleviate restricted availability of anti-malarial

  13. 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

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

    PubMed

    Achan, Jane; Talisuna, Ambrose O; Erhart, Annette; Yeka, Adoke; Tibenderana, James K; Baliraine, Frederick N; Rosenthal, Philip J; D'Alessandro, Umberto

    2011-05-24

    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.

  15. Molecular markers of anti-malarial drug resistance in Central, West and East African children with severe malaria.

    PubMed

    Nguetse, Christian N; Adegnika, Ayola Akim; Agbenyega, Tsiri; Ogutu, Bernhards R; Krishna, Sanjeev; Kremsner, Peter G; Velavan, Thirumalaisamy P

    2017-05-23

    The Plasmodium falciparum multidrug resistance 1 (PfMDR1), P. falciparum Ca(2+)-ATPase (PfATP6) and Kelch-13 propeller domain (PfK13) loci are molecular markers of parasite susceptibility to anti-malarial drugs. Their frequency distributions were determined in the isolates collected from children with severe malaria originating from three African countries. Samples from 287 children with severe malaria [(Gabon: n = 114); (Ghana: n = 89); (Kenya: n = 84)] were genotyped for pfmdr1, pfatp6 and pfk13 loci by DNA sequencing and assessing pfmdr1 copy number variation (CNV) by real-time PCR. Pfmdr1-N86Y mutation was detected in 48, 10 and 10% in Lambaréné, Kumasi and Kisumu, respectively. At codon 184, the prevalence of the mutation was 73% in Lambaréné, 63% in Kumasi and 49% Kisumu. The S1034C and N1042D variants were absent at all three sites, while the frequency of the D1246Y mutation was 1, 3 and 13% in Lambaréné, Kumasi and Kisumu, respectively. Isolates with two pfmdr1 gene copy number predominantly harboured the N86Y wild-type allele and were mostly found in Kumasi (10%) (P < 0.0001). Among the main pfmdr1 haplotypes (NFD, NYD and YFD), NYD was associated with highest parasitaemia (P = 0.04). At the pfatp6 locus, H243Y and A623E mutations were observed at very low frequency at all three sites. The prevalence of the pfatp6 E431K variant was 6, 18 and 17% in Lambaréné, Kumasi and Kisumu, respectively. The L263E and S769N mutations were absent in all isolates. The pfk13 variants associated with artemisinin resistance in Southeast Asia were not observed. Eleven novel substitutions in the pfk13 locus occurring at low frequency were observed. Artemisinins are still highly efficacious in large malaria-endemic regions though declining efficacy has occurred in Southeast Asia. The return of chloroquine-sensitive strains following the removal of drug pressure is observed. However, selection of wild-type alleles in the multidrug-resistance gene and the

  16. Operational strategies of anti-malarial drug campaigns for malaria elimination in Zambia's southern province: a simulation study.

    PubMed

    Stuckey, Erin M; Miller, John M; Littrell, Megan; Chitnis, Nakul; Steketee, Rick

    2016-03-09

    Malaria elimination requires reducing both the potential of mosquitoes to transmit parasites to humans and humans to transmit parasites to mosquitoes. To achieve this goal in Southern province, Zambia a mass test and treat (MTAT) campaign was conducted from 2011-2013 to complement high coverage of long-lasting insecticide-treated nets (LLIN). To identify factors likely to increase campaign effectiveness, a modelling approach was applied to investigate the simulated effect of alternative operational strategies for parasite clearance in southern province. OpenMalaria, a discrete-time, individual-based stochastic model of malaria, was parameterized for the study area to simulate anti-malarial drug administration for interruption of transmission. Simulations were run for scenarios with a range of artemisinin-combination therapies, proportion of the population reached by the campaign, targeted age groups, time between campaign rounds, Plasmodium falciparum test protocols, and the addition of drugs aimed at preventing onward transmission. A sensitivity analysis was conducted to assess uncertainty of simulation results. Scenarios were evaluated based on the reduction in all-age parasite prevalence during the peak transmission month one year following the campaign, compared to the currently-implemented strategy of MTAT 19 % population coverage at pilot and 40 % coverage during the first year of implementation in the presence of 56 % LLIN use and 18 % indoor residual spray coverage. Simulation results suggest the most important determinant of success in reducing prevalence is the population coverage achieved in the campaign, which would require more than 1 year of campaign implementation for elimination. The inclusion of single low-dose primaquine, which acts as a gametocytocide, or ivermectin, which acts as an endectocide, to the drug regimen did not further reduce parasite prevalence one year following the campaign compared to the currently-implemented strategy

  17. Assessment of global reporting of adverse drug reactions for anti-malarials, including artemisinin-based combination therapy, to the WHO Programme for International Drug Monitoring

    PubMed Central

    2011-01-01

    Background In spite of enhanced control efforts, malaria remains a major public health problem causing close to a million deaths annually. With support from several donors, large amounts of artemisinin-based combination therapy (ACT) are being deployed in endemic countries raising safety concerns as little is known about the use of ACT in several of the settings where they are deployed. This project was undertaken to profile the provenance of the pharmacovigilance reporting of all anti-malarials, including ACT to the WHO adverse drug reaction (ADR) database (Vigibase™) over the past 40 years. Methods The WHO Programme for International Drug Monitoring, the Uppsala Monitoring Centre (UMC) provided anonymized extracts of Vigibase™ covering the period 1968-2008. All countries in the programme were clustered according to their malaria control phase and income status. The number of individual case safety reports (ICSRs) of anti-malarials was analyzed according to those clusters. Results From 1968 to 2008, 21,312 ICSRs suspecting anti-malarials were received from 64 countries. Low-income countries, that are also malaria-endemic (categorized as priority 1 countries) submitted only 1.2% of the ICSRs. Only 60 out of 21,312 ICSRs were related to ACT, 51 of which were coming from four sub-Saharan African countries. Although very few ICSRs involved artemisinin-based compounds, many of the adverse events reported were potentially serious. Conclusions This paper illustrates the low reporting of ADRs to anti-malarials in general and ACT in particular. Most reports were submitted by non-endemic and/or high-income countries. Given the current mix of large donor funding, the insufficient information on safety of these drugs, increasing availability of ACT and artemisinin-based monotherapies in public and private sector channels, associated potential for inappropriate use and finally a pipeline of more than 10 new novel anti-malarials in various stages of development, the

  18. Two years post affordable medicines facility for malaria program: availability and prices of anti-malarial drugs in central Ghana.

    PubMed

    Freeman, Alexander; Kwarteng, Anthony; Febir, Lawrence Gyabaa; Amenga-Etego, Seeba; Owusu-Agyei, Seth; Asante, Kwaku Poku

    2017-01-01

    The Affordable Medicines Facility for malaria (AMFm) Program was a subsidy aimed at artemisinin-based combination therapies (ACTs) in order to increase availability, affordability, and market share of ACTs in 8 malaria endemic countries in Africa. The WHO supervised the manufacture of the subsidized products, named them Quality Assured ACTs (QAACT) and printed a Green Leaf Logo on all QAACT packages. Ghana began to receive the subsidized QAACTs in 2010. A cross-sectional stock survey was conducted at 63 licensed chemical shops (LCS) and private pharmacies in two districts of the Brong-Ahafo region of Ghana to determine the availability and price of all anti-malarial treatments. Drug outlets were visited over a 3-weeks period in October and November of 2014, about 2 years after the end of AMFm program. At least one QAACT was available in 88.9% (95% CI 80.9% - 96.8%) of all drug outlets with no difference between urban and rural locations. Non-Assured ACTs (NAACT) were significantly more available in urban drug outlets [75.0% availability (95% CI 59.1% - 90.9%)] than in rural drug outlets [16.1% availability (95% CI 2.4% - 29.9%)]. The top selling product was Artemether Lumefantrine with the Green Leaf Logo, a QAACT. There was a significant difference in the mean price of a QAACT [$1.04 USD (95% CI $0.98 - $1.11)], and the mean price of a NAACT in both the urban and rural areas [$2.46 USD (95% CI $2.11 - $2.81)]. There was no significant difference in the price of any product that was available in urban and rural settings. About 2 years after the AMFm program, subsidized QAACTs in Ghana were widely available and more affordable than NAACTs in the Kintampo North District and Kintampo South Municipality of Ghana. The AMFm program appeared to have mostly succeeded in making QAACTs available and affordable.

  19. Recent progress in the development of anti-malarial quinolones.

    PubMed

    Beteck, Richard M; Smit, Frans J; Haynes, Richard K; N'Da, David D

    2014-08-30

    Available anti-malarial tools have over the ten-year period prior to 2012 dramatically reduced the number of fatalities due to malaria from one million to less than six-hundred and thirty thousand. Although fewer people now die from malaria, emerging resistance to the first-line anti-malarial drugs, namely artemisinins in combination with quinolines and arylmethanols, necessitates the urgent development of new anti-malarial drugs to curb the disease. The quinolones are a promising class of compounds, with some demonstrating potent in vitro activity against the malaria parasite. This review summarizes the progress made in the development of potential anti-malarial quinolones since 2008. The efficacy of these compounds against both asexual blood stages and other stages of the malaria parasite, the nature of putative targets, and a comparison of these properties with anti-malarial drugs currently in clinical use, are discussed.

  20. 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

  1. Plasmodial sugar transporters as anti-malarial drug targets and comparisons with other protozoa

    PubMed Central

    2011-01-01

    Glucose is the primary source of energy and a key substrate for most cells. Inhibition of cellular glucose uptake (the first step in its utilization) has, therefore, received attention as a potential therapeutic strategy to treat various unrelated diseases including malaria and cancers. For malaria, blood forms of parasites rely almost entirely on glycolysis for energy production and, without energy stores, they are dependent on the constant uptake of glucose. Plasmodium falciparum is the most dangerous human malarial parasite and its hexose transporter has been identified as being the major glucose transporter. In this review, recent progress regarding the validation and development of the P. falciparum hexose transporter as a drug target is described, highlighting the importance of robust target validation through both chemical and genetic methods. Therapeutic targeting potential of hexose transporters of other protozoan pathogens is also reviewed and discussed. PMID:21676209

  2. In vitro and in vivo assessment of the anti-malarial activity of Caesalpinia pluviosa

    PubMed Central

    2011-01-01

    Background To overcome the problem of increasing drug resistance, traditional medicines are an important source for potential new anti-malarials. Caesalpinia pluviosa, commonly named "sibipiruna", originates from Brazil and possess multiple therapeutic properties, including anti-malarial activity. Methods Crude extract (CE) was obtained from stem bark by purification using different solvents, resulting in seven fractions. An MTT assay was performed to evaluate cytotoxicity in MCF-7 cells. The CE and its fractions were tested in vitro against chloroquine-sensitive (3D7) and -resistant (S20) strains of Plasmodium falciparum and in vivo in Plasmodium chabaudi-infected mice. In vitro interaction with artesunate and the active C. pluviosa fractions was assessed, and mass spectrometry analyses were conducted. Results At non-toxic concentrations, the 100% ethanolic (F4) and 50% methanolic (F5) fractions possessed significant anti-malarial activity against both 3D7 and S20 strains. Drug interaction assays with artesunate showed a synergistic interaction with the F4. Four days of treatment with this fraction significantly inhibited parasitaemia in mice in a dose-dependent manner. Mass spectrometry analyses revealed the presence of an ion corresponding to m/z 303.0450, suggesting the presence of quercetin. However, a second set of analyses, with a quercetin standard, showed distinct ions of m/z 137 and 153. Conclusions The findings show that the F4 fraction of C. pluviosa exhibits anti-malarial activity in vitro at non-toxic concentrations, which was potentiated in the presence of artesunate. Moreover, this anti-malarial activity was also sustained in vivo after treatment of infected mice. Finally, mass spectrometry analyses suggest that a new compound, most likely an isomer of quercetin, is responsible for the anti-malarial activity of the F4. PMID:21535894

  3. 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

  4. 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

    Jeong, Da Eun; Song, Hye Jin Jin; Lim, Sharon; Lee, Se Jeong Jeong; Lim, Joung Eun; Nam, Do-Hyun; Joo, Kyeung Min; Jeong, Byong Chang; Jeon, Seong Soo; Choi, Han Yong; Lee, Hye Won

    2015-10-20

    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.

  5. A study of toxicity and differential gene expression in murine liver following exposure to anti-malarial drugs: amodiaquine and sulphadoxine-pyrimethamine

    PubMed Central

    2011-01-01

    Background Amodiaquine (AQ) along with sulphadoxine-pyrimethamine (SP) offers effective and cheaper treatment against chloroquine-resistant falciparum malaria in many parts of sub-Saharan Africa. Considering the previous history of hepatitis, agranulocytosis and neutrocytopenia associated with AQ monotherapy, it becomes imperative to study the toxicity of co-administration of AQ and SP. In this study, toxicity and resulting global differential gene expression was analyzed following exposure to these drugs in experimental Swiss mice. Methods The conventional markers of toxicity in serum, oxidative stress parameters in tissue homogenates, histology of liver and alterations in global transcriptomic expression were evaluated to study the toxic effects of AQ and SP in isolation and in combination. Results The combination therapy of AQ and SP results in more pronounced hepatotoxicity as revealed by elevated level of serum ALT, AST with respect to their individual drug exposure regimen. Furthermore, alterations in the activity of major antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase), indicating the development of oxidative stress, was more significant in AQ+SP combination therapy. cDNA microarray results too showed considerably more perturbed gene expression following combination therapy of AQ and SP as compared to their individual drug treatment. Moreover, a set of genes were identified whose expression pattern can be further investigated for identifying a good biomarker for potential anti-malarial hepatotoxicity. Conclusion These observations clearly indicate AQ+SP combination therapy is hepatotoxic in experimental Swiss mice. Microarray results provide a considerable number of potential biomarkers of anti-malarial drug toxicity. These findings hence will be useful for future drug toxicity studies, albeit implications of this study in clinical conditions need to be monitored with cautions. PMID:21529379

  6. Cellular engineering of Artemisia annua and Artemisia dubia with the rol ABC genes for enhanced production of potent anti-malarial drug artemisinin.

    PubMed

    Kiani, Bushra Hafeez; Suberu, John; Mirza, Bushra

    2016-05-04

    Malaria is causing more than half of a million deaths and 214 million clinical cases annually. Despite tremendous efforts for the control of malaria, the global morbidity and mortality have not been significantly changed in the last 50 years. Artemisinin, extracted from the medicinal plant Artemisia sp. is an effective anti-malarial drug. In 2015, elucidation of the effectiveness of artemisinin as a potent anti-malarial drug was acknowledged with a Nobel prize. Owing to the tight market and low yield of artemisinin, an economical way to increase its production is to increase its content in Artemisia sp. through different biotechnological approaches including genetic transformation. Artemisia annua and Artemisia dubia were transformed with rol ABC genes through Agrobacterium tumefacienes and Agrobacterium rhizogenes methods. The artemisinin content was analysed and compared between transformed and untransformed plants with the help of LC-MS/MS. Expression of key genes [Cytochrome P450 (CYP71AV1), aldehyde dehydrogenase 1 (ALDH1), amorpha-4, 11 diene synthase (ADS)] in the biosynthetic pathway of artemisinin and gene for trichome development and sesquiterpenoid biosynthetic (TFAR1) were measured using Quantitative real time PCR (qRT-PCR). Trichome density was analysed using confocal microscope. Artemisinin content was significantly increased in transformed material of both Artemisia species when compared to un-transformed plants. The artemisinin content within leaves of transformed lines was increased by a factor of nine, indicating that the plant is capable of synthesizing much higher amounts than has been achieved so far through traditional breeding. Expression of all artemisinin biosynthesis genes was significantly increased, although variation between the genes was observed. CYP71AV1 and ALDH1 expression levels were higher than that of ADS. Levels of the TFAR1 expression were also increased in all transgenic lines. Trichome density was also significantly

  7. Use of the atmospheric generators for capnophilic bacteria Genbag-CO2 for the evaluation of in vitro Plasmodium falciparum susceptibility to standard anti-malarial drugs

    PubMed Central

    2011-01-01

    Background The aim of this study was to evaluate the cultivation system in which the proper atmospheric conditions for growing Plasmodium falciparum parasites were maintained in a sealed bag. The Genbag® system associated with the atmospheric generators for capnophilic bacteria Genbag CO2® was used for in vitro susceptibility test of nine standard anti-malarial drugs and compared to standard incubator conditions. Methods The susceptibility of 36 pre-identified parasite strains from a wide panel of countries was assessed for nine standard anti-malarial drugs (chloroquine, quinine, mefloquine, monodesethylamodiaquine, lumefantrine, dihydroartemisinin, atovaquone and pyrimethamine) by the standard 42-hour 3H-hypoxanthine uptake inhibition method using the Genbag CO2® system and compared to controlled incubator conditions (5% CO2 and 10% O2). Results The counts per minute values in the control wells in incubator atmospheric conditions (5% CO2 and 10% O2) were significantly higher than those of Genbag® conditions (2738 cpm vs 2282 cpm, p < 0.0001). The geometric mean IC50 estimated under the incubator atmospheric conditions was significantly lower for atovaquone (1.2 vs 2.1 nM, p = 0.0011) and higher for the quinolines: chloroquine (127 vs 94 nM, p < 0.0001), quinine (580 vs 439 nM, p < 0.0001), monodesethylamodiaquine (41.4 vs 31.8 nM, p < 0.0001), mefloquine (57.5 vs 49.7 nM, p = 0.0011) and lumefantrine (23.8 vs 21.2 nM, p = 0.0044). There was no significant difference of IC50 between the 2 conditions for dihydroartemisinin, doxycycline and pyrimethamine. To reduce this difference in term of anti-malarial susceptibility, a specific cut-off was estimated for each drug under Genbag® conditions by regression. The cut-off was estimated at 77 nM for chloroquine (vs 100 nM in 10% O2), 611 nM for quinine (vs 800 nM), 30 nM for mefloquine (vs 30 nM), 61 nM for monodesethylamodiaquine (vs 80 nM) and 1729 nM for pyrimethamine (vs 2000 nM). Conclusions The atmospheric

  8. Susceptibility of human Plasmodium knowlesi infections to anti-malarials

    PubMed Central

    2013-01-01

    Background Evidence suggests that Plasmodium knowlesi malaria in Sarawak, Malaysian Borneo remains zoonotic, meaning anti-malarial drug resistance is unlikely to have developed in the absence of drug selection pressure. Therefore, adequate response to available anti-malarial treatments is assumed. Methods Here the ex vivo sensitivity of human P. knowlesi isolates in Malaysian Borneo were studied, using a WHO schizont maturation assay modified to accommodate the quotidian life cycle of this parasite. The in vitro sensitivities of P. knowlesi H strain adapted from a primate infection to in vitro culture (by measuring the production of Plasmodium lactate dehydrogenase) were also examined together with some assays using Plasmodium falciparum and Plasmodium vivax. Results Plasmodium knowlesi is uniformly highly sensitive to artemisinins, variably and moderately sensitive to chloroquine, and less sensitive to mefloquine. Conclusions Taken together with reports of clinical failures when P. knowlesi is treated with mefloquine, the data suggest that caution is required if using mefloquine in prevention or treatment of P. knowlesi infections, until further studies are undertaken. PMID:24245918

  9. A phase I trial to evaluate the safety and pharmacokinetics of low-dose methotrexate as an anti-malarial drug in Kenyan adult healthy volunteers.

    PubMed

    Chilengi, Roma; Juma, Rashid; Abdallah, Ahmed M; Bashraheil, Mahfudh; Lodenyo, Hudson; Nyakundi, Priscilla; Anabwani, Evelyn; Salim, Amina; Mwambingu, Gabriel; Wenwa, Ednah; Jemutai, Julie; Kipkeu, Chemtai; Oyoo, George O; Muchohi, Simon N; Kokwaro, Gilbert; Niehues, Tim; Lang, Trudie; Nzila, Alexis

    2011-03-16

    Previous investigations indicate that methotrexate, an old anticancer drug, could be used at low doses to treat malaria. A phase I evaluation was conducted to assess the safety and pharmacokinetic profile of this drug in healthy adult male Kenyan volunteers. Twenty five healthy adult volunteers were recruited and admitted to receive a 5 mg dose of methotrexate/day/5 days. Pharmacokinetics blood sampling was carried out at 2, 4, 6, 12 and 24 hours following each dose. Nausea, vomiting, oral ulcers and other adverse events were solicited during follow up of 42 days. The mean age of participants was 23.9 ± 3.3 years. Adherence to protocol was 100%. No grade 3 solicited adverse events were observed. However, one case of transiently elevated liver enzymes, and one serious adverse event (not related to the product) were reported. The maximum concentration (C(max)) was 160-200 nM and after 6 hours, the effective concentration (C(eff)) was <150 nM. Low-dose methotraxate had an acceptable safety profile. However, methotrexate blood levels did not reach the desirable C(eff) of 250-400-nM required to clear malaria infection in vivo. Further dose finding and safety studies are necessary to confirm suitability of this drug as an anti-malarial agent.

  10. Exposure to anti-malarial drugs and monitoring of adverse drug reactions using toll-free mobile phone calls in private retail sector in Sagamu, Nigeria: implications for pharmacovigilance.

    PubMed

    Adedeji, Ahmed A; Sanusi, Bilqees; Tella, Azeez; Akinsanya, Motunrayo; Ojo, Olubusola; Akinwunmi, Mufliat O; Tikare, Olubukola A; Ogunwande, Isiaka A; Ogundahunsi, Omobola A; Ayilara, Olajide O; Ademola, Taofeeqah T; Fehintola, Fatai A; Ogundahunsi, Olumide A T

    2011-08-09

    Adverse drug reactions (ADRs) contribute to ill-health or life-threatening outcomes of therapy during management of infectious diseases. The exposure to anti-malarial and use of mobile phone technology to report ADRs following drug exposures were investigated in Sagamu--a peri-urban community in Southwest Nigeria. Purchase of medicines was actively monitored for 28 days in three Community Pharmacies (CP) and four Patent and Proprietary Medicine Stores (PPMS) in the community. Information on experience of ADRs was obtained by telephone from 100 volunteers who purchased anti-malarials during the 28-day period. A total of 12,093 purchases were recorded during the period. Antibiotics, analgesics, vitamins and anti-malarials were the most frequently purchased medicines. A total of 1,500 complete courses of anti-malarials were purchased (12.4% of total purchases); of this number, purchases of sulphadoxine-pyrimethamine (SP) and chloroquine (CQ) were highest (39.3 and 25.2% respectively). Other anti-malarials purchased were artesunate monotherapy (AS)--16.1%, artemether-lumefantrine (AL) 10.0%, amodiaquine (AQ)--6.6%, quinine (QNN)--1.9%, halofantrine (HF)--0.2% and proguanil (PR)--0.2%. CQ was the cheapest (USD 0.3) and halofantrine the most expensive (USD 7.7). AL was 15.6 times ($4.68) more expensive than CQ. The response to mobile phone monitoring of ADRs was 57% in the first 24 hours (day 1) after purchase and decreased to 33% by day 4. Participants in this monitoring exercise were mostly with low level of education (54%). The findings from this study indicate that ineffective anti-malaria medicines including monotherapies remain widely available and are frequently purchased in the study area. Cost may be a factor in the continued use of ineffective monotherapies. Availability of a toll-free telephone line may facilitate pharmacovigilance and follow up of response to medicines in a resource-poor setting.

  11. Exposure to anti-malarial drugs and monitoring of adverse drug reactions using toll-free mobile phone calls in private retail sector in Sagamu, Nigeria: implications for pharmacovigilance

    PubMed Central

    2011-01-01

    Background Adverse drug reactions (ADRs) contribute to ill-health or life-threatening outcomes of therapy during management of infectious diseases. The exposure to anti-malarial and use of mobile phone technology to report ADRs following drug exposures were investigated in Sagamu - a peri-urban community in Southwest Nigeria. Methods Purchase of medicines was actively monitored for 28 days in three Community Pharmacies (CP) and four Patent and Proprietary Medicine Stores (PPMS) in the community. Information on experience of ADRs was obtained by telephone from 100 volunteers who purchased anti-malarials during the 28-day period. Results and Discussion A total of 12,093 purchases were recorded during the period. Antibiotics, analgesics, vitamins and anti-malarials were the most frequently purchased medicines. A total of 1,500 complete courses of anti-malarials were purchased (12.4% of total purchases); of this number, purchases of sulphadoxine-pyrimethamine (SP) and chloroquine (CQ) were highest (39.3 and 25.2% respectiuvely). Other anti-malarials purchased were artesunate monotherapy (AS) - 16.1%, artemether-lumefantrine (AL) 10.0%, amodiaquine (AQ) - 6.6%, quinine (QNN) - 1.9%, halofantrine (HF) - 0.2% and proguanil (PR) - 0.2%. CQ was the cheapest (USD 0.3) and halofantrine the most expensive (USD 7.7). AL was 15.6 times ($4.68) more expensive than CQ. The response to mobile phone monitoring of ADRs was 57% in the first 24 hours (day 1) after purchase and decreased to 33% by day 4. Participants in this monitoring exercise were mostly with low level of education (54%). Conclusion The findings from this study indicate that ineffective anti-malaria medicines including monotherapies remain widely available and are frequently purchased in the study area. Cost may be a factor in the continued use of ineffective monotherapies. Availability of a toll-free telephone line may facilitate pharmacovigilance and follow up of response to medicines in a resource-poor setting

  12. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. 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

  14. Repurposing the anti-malarial drug dihydroartemisinin suppresses metastasis of non-small-cell lung cancer via inhibiting NF-κB/GLUT1 axis

    PubMed Central

    Jiang, Jie; Geng, Guojun; Yu, Xiuyi; Liu, Hongming; Gao, Jing; An, Hanxiang; Cai, Chengfu; Li, Ning; Shen, Dongyan; Wu, Xiaoqiang; Zheng, Lisheng; Mi, Yanjun; Yang, Shuyu

    2016-01-01

    Non-small-cell lung cancer (NSCLC) is an aggressive malignancy and long-term survival remains unsatisfactory for patients with metastatic and recurrent disease. Repurposing the anti-malarial drug dihydroartemisinin (DHA) has been proved to possess potent antitumor effect on various cancers. However, the effects of DHA in preventing the invasion of NSCLC cells have not been studied. In the present study, we determined the inhibitory effects of DHA on invasion and migration and the possible mechanisms involved using A549 and H1975 cells. DHA inhibited in vitro migration and invasion of NSCLC cells even in low concentration with little cytotoxicity. Additionally, low concentration DHA also inhibited Warburg effect in NSCLC cells. Mechanically, DHA negatively regulates NF-κB signaling to inhibit the GLUT1 translocation. Blocking the NF-κB signaling largely abolishes the inhibitory effects of DHA on the translocation of GLUT1 to the plasma membrane and the Warburg effect. Furthermore, GLUT1 knockdown significantly decreased the inhibition of invasion, and migration by DHA. Our results suggested that DHA can inhibit metastasis of NSCLC by targeting glucose metabolism via inhibiting NF-κB signaling pathway and DHA may deserve further investigation in NSCLC treatment. PMID:27895313

  15. Repurposing the anti-malarial drug dihydroartemisinin suppresses metastasis of non-small-cell lung cancer via inhibiting NF-κB/GLUT1 axis.

    PubMed

    Jiang, Jie; Geng, Guojun; Yu, Xiuyi; Liu, Hongming; Gao, Jing; An, Hanxiang; Cai, Chengfu; Li, Ning; Shen, Dongyan; Wu, Xiaoqiang; Zheng, Lisheng; Mi, Yanjun; Yang, Shuyu

    2016-12-27

    Non-small-cell lung cancer (NSCLC) is an aggressive malignancy and long-term survival remains unsatisfactory for patients with metastatic and recurrent disease. Repurposing the anti-malarial drug dihydroartemisinin (DHA) has been proved to possess potent antitumor effect on various cancers. However, the effects of DHA in preventing the invasion of NSCLC cells have not been studied. In the present study, we determined the inhibitory effects of DHA on invasion and migration and the possible mechanisms involved using A549 and H1975 cells. DHA inhibited in vitro migration and invasion of NSCLC cells even in low concentration with little cytotoxicity. Additionally, low concentration DHA also inhibited Warburg effect in NSCLC cells. Mechanically, DHA negatively regulates NF-κB signaling to inhibit the GLUT1 translocation. Blocking the NF-κB signaling largely abolishes the inhibitory effects of DHA on the translocation of GLUT1 to the plasma membrane and the Warburg effect. Furthermore, GLUT1 knockdown significantly decreased the inhibition of invasion, and migration by DHA. Our results suggested that DHA can inhibit metastasis of NSCLC by targeting glucose metabolism via inhibiting NF-κB signaling pathway and DHA may deserve further investigation in NSCLC treatment.

  16. Anti-malarial activities of Andrographis paniculata and Hedyotis corymbosa extracts and their combination with curcumin

    PubMed Central

    Mishra, Kirti; Dash, Aditya P; Swain, Bijay K; Dey, Nrisingha

    2009-01-01

    Background Herbal extracts of Andrographis paniculata (AP) and Hedyotis corymbosa (HC) are known as hepato-protective and fever-reducing drugs since ancient time and they have been used regularly by the people in the south Asian sub-continent. Methanolic extracts of these two plants were tested in vitro on choloroquine sensitive (MRC-pf-20) and resistant (MRC-pf-303) strains of Plasmodium falciparum for their anti-malarial activity. Methods Growth inhibition was determined using different concentrations of these plant extracts on synchronized P. falciparum cultures at the ring stage. The interactions between these two plant extracts and individually with curcumin were studied in vitro. The performance of these two herbal extracts in isolation and combination were further evaluated in vivo on Balb/c mice infected with Plasmodium berghei ANKA and their efficacy was compared with that of curcumin. The in vivo toxicity of the plant derived compounds as well as their parasite stage-specificity was studied. Results The 50% inhibitory concentration (IC50) of AP (7.2 μg/ml) was found better than HC (10.8 μg/ml). Combination of these two herbal drugs showed substantial enhancement in their anti-malarial activity. Combinatorial effect of each of these with curcumin also revealed anti-malarial effect. Additive interaction between the plant extracts (AP + HC) and their individual synergism with curcumin (AP+CUR, HC+CUR) were evident from this study. Increased in vivo potency was also observed with the combination of plant extracts over the individual extracts and curcumin. Both the plant extracts were found to inhibit the ring stage of the parasite and did not show any in vivo toxicity, whether used in isolation or in combination. Conclusion Both these two plant extracts in combination with curcumin could be an effective, alternative source of herbal anti-malarial drugs. PMID:19216765

  17. Slowing down glioblastoma progression in mice by running or the anti-malarial drug dihydroartemisinin? Induction of oxidative stress in murine glioblastoma therapy

    PubMed Central

    Lemke, Dieter; Pledl, Hans-Werner; Zorn, Markus; Jugold, Manfred; Green, Ed; Blaes, Jonas; Löw, Sarah; Hertenstein, Anne; Ott, Martina; Sahm, Felix; Steffen, Ann-Catherine; Weiler, Markus; Winkler, Frank; Platten, Michael

    2016-01-01

    Influencing cancer metabolism by lifestyle changes is an attractive strategy as - if effective - exercise-induced problems may be less severe than those induced by classical anti-cancer therapies. Pursuing this idea, clinical trials evaluated the benefit of e.g. different diets such as the ketogenic diet, intermittent caloric restriction and physical exercise (PE) in the primary and secondary prevention of different cancer types. PE proved to be beneficial in the context of breast and colon cancer. Glioblastoma has a dismal prognosis, with an average overall survival of about one year despite maximal safe resection, concomitant radiochemotherapy with temozolomide followed by adjuvant temozolomide therapy. Here, we focused on the influence of PE as an isolated and adjuvant treatment in murine GB therapy. PE did not reduce toxic side effects of chemotherapy in mice administered in a dose escalating scheme as shown before for starvation. Although regular treadmill training on its own had no obvious beneficial effects, its combination with temozolomide was beneficial in the treatment of glioblastoma-bearing mice. As PE might partly act through the induction of reactive oxygen species, dihydroartemisinin - an approved anti-malarial drug which induces oxidative stress in glioma cells - was further evaluated in vitro and in vivo. Dihydroartemisinin showed anti-glioma activity by promoting autophagy, reduced the clonogenic survival and proliferation capacity of glioma cells, and prolonged the survival of tumor bearing mice. Using the reactive oxygen species scavenger n-acetyl-cysteine these effects were in part reversible, suggesting that dihydroartemisinin partly acts through the generation of reactive oxygen species. PMID:27447560

  18. Slowing down glioblastoma progression in mice by running or the anti-malarial drug dihydroartemisinin? Induction of oxidative stress in murine glioblastoma therapy.

    PubMed

    Lemke, Dieter; Pledl, Hans-Werner; Zorn, Markus; Jugold, Manfred; Green, Ed; Blaes, Jonas; Löw, Sarah; Hertenstein, Anne; Ott, Martina; Sahm, Felix; Steffen, Ann-Catherine; Weiler, Markus; Winkler, Frank; Platten, Michael; Dong, Zhen; Wick, Wolfgang

    2016-08-30

    Influencing cancer metabolism by lifestyle changes is an attractive strategy as - if effective - exercise-induced problems may be less severe than those induced by classical anti-cancer therapies. Pursuing this idea, clinical trials evaluated the benefit of e.g. different diets such as the ketogenic diet, intermittent caloric restriction and physical exercise (PE) in the primary and secondary prevention of different cancer types. PE proved to be beneficial in the context of breast and colon cancer.Glioblastoma has a dismal prognosis, with an average overall survival of about one year despite maximal safe resection, concomitant radiochemotherapy with temozolomide followed by adjuvant temozolomide therapy. Here, we focused on the influence of PE as an isolated and adjuvant treatment in murine GB therapy.PE did not reduce toxic side effects of chemotherapy in mice administered in a dose escalating scheme as shown before for starvation. Although regular treadmill training on its own had no obvious beneficial effects, its combination with temozolomide was beneficial in the treatment of glioblastoma-bearing mice. As PE might partly act through the induction of reactive oxygen species, dihydroartemisinin - an approved anti-malarial drug which induces oxidative stress in glioma cells - was further evaluated in vitro and in vivo. Dihydroartemisinin showed anti-glioma activity by promoting autophagy, reduced the clonogenic survival and proliferation capacity of glioma cells, and prolonged the survival of tumor bearing mice. Using the reactive oxygen species scavenger n-acetyl-cysteine these effects were in part reversible, suggesting that dihydroartemisinin partly acts through the generation of reactive oxygen species.

  19. In silico and in vivo anti-malarial studies of 18β glycyrrhetinic acid from Glycyrrhiza glabra.

    PubMed

    Kalani, Komal; Agarwal, Jyoti; Alam, Sarfaraz; Khan, Feroz; Pal, Anirban; Srivastava, Santosh Kumar

    2013-01-01

    Malaria is one of the most prevailing fatal diseases causing between 1.2 and 2.7 million deaths all over the world each year. Further, development of resistance against the frontline anti-malarial drugs has created an alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-malarial agents possessing novel modes of action. Over the past few years triterpenoids from higher plants have shown a wide range of anti-malarial activities. As a part of our drug discovery program for anti-malarial agents from Indian medicinal plants, roots of Glycyrrhizaglabra were chemically investigated, which resulted in the isolation and characterization of 18β-glycyrrhetinic acid (GA) as a major constituent. The in vitro studies against P. falciparum showed significant (IC50 1.69 µg/ml) anti-malarial potential for GA. Similarly, the molecular docking studies showed adequate docking (LibDock) score of 71.18 for GA and 131.15 for standard anti-malarial drug chloroquine. Further, in silico pharmacokinetic and drug-likeness studies showed that GA possesses drug-like properties. Finally, in vivo evaluation showed a dose dependent anti-malarial activity ranging from 68-100% at doses of 62.5-250 mg/kg on day 8. To the best of our knowledge this is the first ever report on the anti-malarial potential of GA. Further work on optimization of the anti-malarial lead is under progress.

  20. Prescribing Pattern of Anti-malarial Drugs with Particular Reference to the use of Artesunate in Complicated Plasmodium Vivax Cases

    PubMed Central

    Singh, Ashutosh Kumar; Khan, Mohd Sajid

    2014-01-01

    Background: In developing countries, Malaria has been found to be one of the most common cause of fever and morbidity, particularly among infants and young children. Therefore, its drug utilization studies should be carried out to know the rationality of treatment. Aim: To evaluate the use of antimalarial agents in children with a diagnosis of Malaria and visited to OPD & IPD Paediatric department of a tertiary care teaching hospital. Materials and Methods: This was a prospective six months study based on a Medication Utilization Form, which has been designed in consultation with the paediatrician. One hundred eighty three children <12 y of age were selected on the basis of inclusion and exclusion criteria. Results: Out of 183 patients, 110 were infected with Plasmodium falciparum (60.10%) and 73 with Plasmodium vivax (39.89%). Most of the patients were male, 56.83% and 43.16% were female patients. Most of the complicated cases were found from Plasmodium falciparum (n = 110) than Plasmodium vivax (n=15). In prescriptions with monotherapy, Artesunate (n=101) was found to be the most commonly prescribed drug and in prescriptions containing more than one drug, Artesunate – lumefantrine (n=125) combinations were frequently used. Most of the drugs were prescribed by oral route (n=285), than the parenteral route (n=140). The average number of drugs per encounter was 2.32 and only 4.50% drugs were prescribed by generic name. Average drug cost per prescription in complicated cases was found to be higher (185.5 INR) than uncomplicated cases (115 INR). Conclusion: Artemisinin were used as first line drugs irrespective of the causative agent for malaria, which is not recommended, however has been found to be effective in complicated cases of Plasmodium vivax also. The cost of the prescription was higher. Interventions to rectify over prescription of injectables necessary to further improve rational drug use in our facility. Also, there should be an awareness program

  1. A cross-sectional study of the availability and price of anti-malarial medicines and malaria rapid diagnostic tests in private sector retail drug outlets in rural Western Kenya, 2013.

    PubMed

    Kioko, Urbanus; Riley, Christina; Dellicour, Stephanie; Were, Vincent; Ouma, Peter; Gutman, Julie; Kariuki, Simon; Omar, Ahmeddin; Desai, Meghna; Buff, Ann M

    2016-07-12

    Although anti-malarial medicines are free in Kenyan public health facilities, patients often seek treatment from private sector retail drug outlets. In mid-2010, the Affordable Medicines Facility-malaria (AMFm) was introduced to make quality-assured artemisinin-based combination therapy (ACT) accessible and affordable in private and public sectors. Private sector retail drug outlets stocking anti-malarial medications within a surveillance area of approximately 220,000 people in a malaria perennial high-transmission area in rural western Kenya were identified via a census in September 2013. A cross-sectional study was conducted in September-October 2013 to determine availability and price of anti-malarial medicines and malaria rapid diagnostic tests (RDTs) in drug outlets. A standardized questionnaire was administered to collect drug outlet and personnel characteristics and availability and price of anti-malarials and RDTs. Of 181 drug outlets identified, 179 (99 %) participated in the survey. Thirteen percent were registered pharmacies, 25 % informal drug shops, 46 % general shops, 13 % homesteads and 2 % other. One hundred sixty-five (92 %) had at least one ACT type: 162 (91 %) had recommended first-line artemether-lumefantrine (AL), 22 (12 %) had recommended second-line dihydroartemisinin-piperaquine (DHA-PPQ), 85 (48 %) had sulfadoxine-pyrimethamine (SP), 60 (34 %) had any quinine (QN) formulation, and 14 (8 %) had amodiaquine (AQ) monotherapy. The mean price (range) of an adult treatment course for AL was $1.01 ($0.35-4.71); DHA-PPQ was $4.39 ($0.71-7.06); QN tablets were $2.24 ($0.12-4.71); SP was $0.62 ($0.24-2.35); AQ monotherapy was $0.42 ($0.24-1.06). The mean AL price with or without the AMFm logo did not differ significantly ($1.01 and 1.07, respectively; p = 0.45). Only 17 (10 %) drug outlets had RDTs; 149 (84 %) never stocked RDTs. The mean RDT price was $0.92 ($0.24-2.35). Most outlets never stocked RDTs; therefore, testing prior to

  2. 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

  3. Effect of selected anti-malarial drugs on the blood chemistry and brain serotonin levels in male rabbits.

    PubMed

    Eigbibhalu, Ukpo Grace; Albert Taiwo, Ebuehi Osaretin; Douglass, Idiakheua Akhabue; Abimbola, Efunogbon Aderonke

    2013-01-01

    The effects of oral administration of sulfadoxine - pyrimethamine (SP), artesunate (A) and sulfadoxine - pyrimethamine - artesunate (SPA) on blood chemistry and brain serotonin in rabbits were investigated. Forty rabbits were divided into four groups of ten animals each. The group that served as the control received 2ml of distilled water while the other groups were received 1.25/25mg base/kg body weight of SP, 3.3mg/kg body weight of A and 1.25/25mg base/kg body weight of SP plus 3.3mg/kg body weight of A respectively by oral route daily for 3 days in a week for four weeks. At the end of each week of drug administration, three rabbits from each group were anaesthetized, blood was taken from the jugular veins using sterile needle and serum was extracted. The rabbits were sacrificed by decapitation; the liver and brain tissues were excised and homogenized. Total blood protein, cholesterol, triglyceride, albumin, creatinine and urea concentrations, creatine kinase, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase, ALP activities were assayed using CX5 synchron autoanalyzer. The brain and liver serotonin levels were determined using high performance liquid chromatography (HPLC). There were no significant differences (P < 0.05) in the concentrations of serum albumin, urea, creatinine, cholesterol and triglyceride of rabbits administered SP, A and SPA for 4 weeks, except in serum total protein. No significant differences existed in the activities of AST, ALT and ALP, except in creatine kinase which was elevated in the control. The brain serotonin levels of rabbits administered SP, A and SPA were significantly higher as compared to the control throughout the duration of the study Data of the study indicate that oral administration of SP, A or SPA in rabbits do not affect blood chemistry, but affected brain serotonin levels and could alter some neural functions.

  4. Assessment of molecular markers for anti-malarial drug resistance after the introduction and scale-up of malaria control interventions in western Kenya.

    PubMed

    Shah, Monica; Omosun, Yusuf; Lal, Ashima; Odero, Christopher; Gatei, Wangeci; Otieno, Kephas; Gimnig, John E; ter Kuile, Feiko; Hawley, William A; Nahlen, Bernard; Kariuki, Simon; Walker, Edward; Slutsker, Laurence; Hamel, Mary; Shi, Ya Ping

    2015-02-14

    Although it is well known that drug pressure selects for drug-resistant parasites, the role of transmission reduction by insecticide-treated bed nets (ITNs) on drug resistance remains unclear. In this study, the drug resistance profile of current and previous first-line anti-malarials in Kenya was assessed within the context of drug policy change and scale-up of ITNs. National first-line treatment changed from chloroquine (CQ) to sulphadoxine-pyrimethamine (SP) in 1998 and to artemether-lumefantrine (AL) in 2004. ITN use was scaled-up in the Asembo, Gem and Karemo areas of western Kenya in 1997, 1999 and 2006, respectively. Smear-positive samples (N = 253) collected from a 2007 cross-sectional survey among children in Asembo, Gem and Karemo were genotyped for mutations in pfcrt and pfmdr1 (CQ), dhfr and dhps (SP), and at pfmdr-N86 and the gene copy number in pfmdr1 (lumefantrine). Results were compared among the three geographic areas in 2007 and to retrospective molecular data from children in Asembo in 2001. In 2007, 69 and 85% of samples harboured the pfmdr1-86Y mutation and dhfr/dhps quintuple mutant, respectively, with no significant differences by study area. However, the prevalence of the pfcrt-76T mutation differed significantly among areas (p <0.02), between 76 and 94%, with the highest prevalence in Asembo. Several 2007 samples carried mutations at dhfr-164L, dhps-436A, or dhps-613T. From 2001 to 2007, there were significant increases in the pfcrt-76T mutation from 82 to 94% (p <0.03), dhfr/dhps quintuple mutant from 62 to 82% (p <0.03), and an increase in the septuple CQ and SP combined mutant haplotype, K 76 Y 86 I 51 R 59 N 108 G 437 E 540 , from 28 to 39%. The prevalence of the pfmdr1-86Y mutation remained unchanged. All samples were single copy for pfmdr1. Molecular markers associated with lumefantrine resistance were not detected in 2007. More recent samples will be needed to detect any selective effects by AL. The prevalence of CQ and SP

  5. Plasmodium falciparum in vitro continuous culture conditions: A comparison of parasite susceptibility and tolerance to anti-malarial drugs throughout the asexual intra-erythrocytic life cycle.

    PubMed

    Duffy, Sandra; Avery, Vicky M

    2017-07-15

    The continuous culture of Plasmodium falciparum is often seen as a means to an end, that end being to probe the biology of the parasite in question, and ultimately for many in the malaria drug discovery arena, to identify means of killing the parasite in order to treat malaria. In vitro continuous culture of Plasmodium falciparum is a fundamental requirement when undertaking malaria research where the primary objectives utilise viable parasites of a desired lifecycle stage. This investigation, and resulting data, compared the impact culturing Plasmodium falciparum long term (4 months) in different environmental conditions had on experimental outcomes and thus conclusions. The example presented here focused specifically on the effect culture conditions had on the in vitro tolerance of Plasmodium falciparum to standard anti-malarial drugs, including artemisinin and lumefantrine. Historical data from an independent experiment for 3D7-ALB (5% O2) was also compared with that obtained from this study. We concluded that parasites cultured for several months in media supplemented with a serum substitute such as Albumax II(®) or within hyperoxic conditions (21% O2), demonstrate highly variable responses to artemisinin and lumefantrine but not all anti-malarial drugs, when compared to those cultured in human serum in combination with Albumax II(®) under normoxic conditions (5% O2) for the parasite. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Polymerase chain reaction and molecular genotyping to monitor parasitological response to anti-malarial chemotherapy in the Peruvian Amazon.

    PubMed

    Ayala, Everick; Lescano, Andrés G; Gilman, Robert H; Calderón, Maritza; Pinedo, Viviana V; Terry, Hilja; Cabrera, Lilia; Vinetz, Joseph M

    2006-04-01

    Over the past decade, anti-malarial drug resistance has rapidly become a major public health problem in the Peruvian Amazon. This study compared polymerase chain reaction (PCR) to light microscopy for diagnosing and monitoring the parasitological response of malaria patients to anti-malarial chemotherapy in the Peruvian Amazon region of Iquitos. Typing of P. falciparum using MSP1, MSP2, and glutamine-rich protein distinguished among infecting parasites. Most (73%) P. falciparum patients were parasitologically resistant to sulfadoxine-pyrimethamine (RI = 10, RII = 1). Sensitivity of microscopy was lower than PCR (69% for P. vivax and 78% for P. falciparum), but parasite clearance times were comparable between microscopy and PCR. PCR sensitively and specifically detected mixed infections and low-level parasitemia indicative of drug resistance, making this approach of practical use for the control of malaria at the public health level. Genotyping malaria parasites will be useful to distinguish drug failure from new infections in clinical trials of anti-malarial drugs in the Peruvian Amazon region.

  7. Monitoring of efficacy and safety of artemisinin-based anti-malarials for treatment of uncomplicated malaria: a review of evidence of implementation of anti-malarial therapeutic efficacy trials in Tanzania.

    PubMed

    Shayo, Alex; Buza, Joram; Ishengoma, Deus S

    2015-03-29

    Prompt diagnosis and effective treatment are considered the cornerstones of malaria control and artemisinin-based combination therapy (ACT) is currently the main anti-malarial drugs used for case management. After deployment of ACT due to widespread parasite resistance to the cheap and widely used anti-malarial drugs, chloroquine and sulphadoxine/pyrimethamine, the World Health Organization recommends regular surveillance to monitor the efficacy of the new drugs. The present paper assessed the implementation of anti-malarial efficacy testing for monitoring the therapeutic efficacy of ACT for treatment of uncomplicated malaria in Tanzania before and after policy changes in 2006. A literature search was performed for published clinical trials conducted in Tanzania from 2001 to 2014. It focused on studies which assessed at least one form of ACT for treatment of uncomplicated falciparum malaria in children less than 10 years and reported efficacy and safety of the tested anti-malarials. References were imported into the Endnote library and duplicates removed. An electronic matrix was developed in Microsoft Excel followed by full text review with predetermined criteria. Studies were independently assessed and information related to ACT efficacy and safety extracted. Nine papers were selected from 125 papers screened. The efficacy of both artemether-lumefantrine (AL) and artesunate-amodiaquine (AS + AQ) against uncomplicated P. falciparum infections in Tanzania was high with PCR-corrected cure rates on day 28 of 91-100% and 88-93.8%, respectively. The highest day-3 parasite positivity rate was 1.4%. Adverse events ranged from mild to serious but were not directly attributed to the drugs. ACT is efficacious and safe for treatment of uncomplicated malaria in Tanzania. However, few trials were conducted in Tanzania before and after policy changes in 2006 and thus more surveillance should be urgently undertaken to detect future changes in parasite sensitivity to ACT.

  8. Biological evaluation of hydroxynaphthoquinones as anti-malarials

    PubMed Central

    2013-01-01

    Background The hydroxynaphthoquinones have been extensively investigated over the past 50 years for their anti-malarial activity. One member of this class, atovaquone, is combined with proguanil in Malarone®, an important drug for the treatment and prevention of malaria. Methods Anti-malarial activity was assessed in vitro for a series of 3-alkyl-2-hydroxy-1,4-naphthoquinones (N1-N5) evaluating the parasitaemia after 48 hours of incubation. Potential cytotoxicity in HEK293T cells was assessed using the MTT assay. Changes in mitochondrial membrane potential of Plasmodium were measured using the fluorescent dye Mitrotracker Red CMXROS. Results Four compounds demonstrated IC50s in the mid-micromolar range, and the most active compound, N3, had an IC50 of 443 nM. N3 disrupted mitochondrial membrane potential, and after 1 hour presented an IC50ΔΨmit of 16 μM. In an in vitro cytotoxicity assay using HEK 293T cells N3 demonstrated no cytotoxicity at concentrations up to 16 μM. Conclusions N3 was a potent inhibitor of mitochondrial electron transport, had nanomolar activity against cultured Plasmodium falciparum and showed minimal cytotoxicity. N3 may serve as a starting point for the design of new hydroxynaphthoquinone anti-malarials. PMID:23841934

  9. Biological activities of nitidine, a potential anti-malarial lead compound

    PubMed Central

    2012-01-01

    Background Nitidine is thought to be the main active ingredient in several traditional anti-malarial remedies used in different parts of the world. The widespread use of these therapies stresses the importance of studying this molecule in the context of malaria control. However, little is known about its potential as an anti-plasmodial drug, as well as its mechanism of action. Methods In this study, the anti-malarial potential of nitidine was evaluated in vitro on CQ-sensitive and -resistant strains. The nitidine's selectivity index compared with cancerous and non-cancerous cell lines was then determined. In vivo assays were then performed, using the four-day Peter's test methodology. To gain information about nitidine's possible mode of action, its moment of action on the parasite cell cycle was studied, and its localization inside the parasite was determined using confocal microscopy. The in vitro abilities of nitidine to bind haem and to inhibit β-haematin formation were also demonstrated. Results Nitidine showed similar in vitro activity in CQ-sensitive and resistant strains, and also a satisfying selectivity index (> 10) when compared with a non-cancerous cells line. Its in vivo activity was moderate; however, no sign of acute toxicity was observed during treatment. Nitidine's moment of action on the parasite cycle showed that it could not interfere with DNA replication; this was consistent with the observation that nitidine did not localize in the nucleus, but rather in the cytoplasm of the parasite. Nitidine was able to form a 1-1 complex with haem in vitro and also inhibited β-haematin formation with the same potency as chloroquine. Conclusion Nitidine can be considered a potential anti-malarial lead compound. Its ability to complex haem and inhibit β-haematin formation suggests a mechanism of action similar to that of chloroquine. The anti-malarial activity of nitidine could therefore be improved by structural modification of this molecule to increase

  10. Adverse drug events resulting from use of drugs with sulphonamide-containing anti-malarials and artemisinin-based ingredients: findings on incidence and household costs from three districts with routine demographic surveillance systems in rural Tanzania

    PubMed Central

    2013-01-01

    Background Anti-malarial regimens containing sulphonamide or artemisinin ingredients are widely used in malaria-endemic countries. However, evidence of the incidence of adverse drug reactions (ADR) to these drugs is limited, especially in Africa, and there is a complete absence of information on the economic burden such ADR place on patients. This study aimed to document ADR incidence and associated household costs in three high malaria transmission districts in rural Tanzania covered by demographic surveillance systems. Methods Active and passive surveillance methods were used to identify ADR from sulphadoxine-pyrimethamine (SP) and artemisinin (AS) use. ADR were identified by trained clinicians at health facilities (passive surveillance) and through cross-sectional household surveys (active surveillance). Potential cases were followed up at home, where a complete history and physical examination was undertaken, and household cost data collected. Patients were classified as having ‘possible’ or ‘probable’ ADR by a physician. Results A total of 95 suspected ADR were identified during a two-year period, of which 79 were traced, and 67 reported use of SP and/or AS prior to ADR onset. Thirty-four cases were classified as ‘probable’ and 33 as ‘possible’ ADRs. Most (53) cases were associated with SP monotherapy, 13 with the AS/SP combination (available in one of the two areas only), and one with AS monotherapy. Annual ADR incidence per 100,000 exposures was estimated based on ‘probable’ ADR only at 5.6 for AS/SP in combination, and 25.0 and 11.6 for SP monotherapy. Median ADR treatment costs per episode ranged from US$2.23 for those making a single provider visit to US$146.93 for patients with four visits. Seventy-three per cent of patients used out-of-pocket funds or sold part of their farm harvests to pay for treatment, and 19% borrowed money. Conclusion Both passive and active surveillance methods proved feasible methods for anti-malarial ADR

  11. Poor quality vital anti-malarials in Africa - an urgent neglected public health priority.

    PubMed

    Newton, Paul N; Green, Michael D; Mildenhall, Dallas C; Plançon, Aline; Nettey, Henry; Nyadong, Leonard; Hostetler, Dana M; Swamidoss, Isabel; Harris, Glenn A; Powell, Kristen; Timmermans, Ans E; Amin, Abdinasir A; Opuni, Stephen K; Barbereau, Serge; Faurant, Claude; Soong, Ray C W; Faure, Kevin; Thevanayagam, Jonarthan; Fernandes, Peter; Kaur, Harparkash; Angus, Brian; Stepniewska, Kasia; Guerin, Philippe J; Fernández, Facundo M

    2011-12-13

    Plasmodium falciparum malaria remains a major public health problem. A vital component of malaria control rests on the availability of good quality artemisinin-derivative based combination therapy (ACT) at the correct dose. However, there are increasing reports of poor quality anti-malarials in Africa. Seven collections of artemisinin derivative monotherapies, ACT and halofantrine anti-malarials of suspicious quality were collected in 2002/10 in eleven African countries and in Asia en route to Africa. Packaging, chemical composition (high performance liquid chromatography, direct ionization mass spectrometry, X-ray diffractometry, stable isotope analysis) and botanical investigations were performed. Counterfeit artesunate containing chloroquine, counterfeit dihydroartemisinin (DHA) containing paracetamol (acetaminophen), counterfeit DHA-piperaquine containing sildenafil, counterfeit artemether-lumefantrine containing pyrimethamine, counterfeit halofantrine containing artemisinin, and substandard/counterfeit or degraded artesunate and artesunate+amodiaquine in eight countries are described. Pollen analysis was consistent with manufacture of counterfeits in eastern Asia. These data do not allow estimation of the frequency of poor quality anti-malarials in Africa. Criminals are producing diverse harmful anti-malarial counterfeits with important public health consequences. The presence of artesunate monotherapy, substandard and/or degraded and counterfeit medicines containing sub-therapeutic amounts of unexpected anti-malarials will engender drug resistance. With the threatening spread of artemisinin resistance to Africa, much greater investment is required to ensure the quality of ACTs and removal of artemisinin monotherapies. The International Health Regulations may need to be invoked to counter these serious public health problems.

  12. Fake anti-malarials: start with the facts.

    PubMed

    Kaur, Harparkash; Clarke, Siȃn; Lalani, Mirza; Phanouvong, Souly; Guérin, Philippe; McLoughlin, Andrew; Wilson, Benjamin K; Deats, Michael; Plançon, Aline; Hopkins, Heidi; Miranda, Debora; Schellenberg, David

    2016-02-13

    This meeting report presents the key findings and discussion points of a 1-day meeting entitled 'Fake anti-malarials: start with the facts' held on 28th May 2015, in Geneva, Switzerland, to disseminate the findings of the artemisinin combination therapy consortium's drug quality programme. The teams purchased over 10,000 samples, using representative sampling approaches, from six malaria endemic countries: Equatorial Guinea (Bioko Island), Cambodia, Ghana, Nigeria, Rwanda and Tanzania. Laboratory analyses of these samples showed that falsified anti-malarials (<8 %) were found in just two of the countries, whilst substandard artemisinin-based combinations were present in all six countries and, artemisinin-based monotherapy tablets are still available in some places despite the fact that the WHO has urged regulatory authorities in malaria-endemic countries to take measures to halt the production and marketing of these oral monotherapies since 2007. This report summarizes the presentations that reviewed the public health impact of falsified and substandard drugs, sampling strategies, techniques for drug quality analysis, approaches to strengthen health systems capacity for the surveillance of drug quality, and the ensuing discussion points from the dissemination meeting.

  13. Access to artesunate-amodiaquine, quinine and other anti-malarials: policy and markets in Burundi

    PubMed Central

    2011-01-01

    Background Malaria is the leading cause of morbidity and mortality in post-conflict Burundi. To counter the increasing challenge of anti-malarial drug resistance and improve highly effective treatment Burundi adopted artesunate-amodiaquine (AS-AQ) as first-line treatment for uncomplicated Plasmodium falciparum malaria and oral quinine as second-line treatment in its national treatment policy in 2003. Uptake of this policy in the public, private and non-governmental (NGO) retail market sectors of Burundi is relatively unknown. This study was conducted to evaluate access to national policy recommended anti-malarials. Methods Adapting a standardized methodology developed by Health Action International/World Health Organization (HAI/WHO), a cross-sectional survey of 70 (24 public, 36 private, and 10 NGO) medicine outlets was conducted in three regions of Burundi, representing different levels of transmission of malaria. The availability on day of the survey, the median prices, and affordability (in terms of number of days' wages to purchase treatment) of AS-AQ, quinine and other anti-malarials were calculated. Results Anti-malarials were stocked in all outlets surveyed. AS-AQ was available in 87.5%, 33.3%, and 90% of public, private, and NGO retail outlets, respectively. Quinine was the most common anti-malarial found in all outlet types. Non-policy recommended anti-malarials were mainly found in the private outlets (38.9%) compared to public (4.2%) and NGO (0%) outlets. The median price of a course of AS-AQ was US$0.16 (200 Burundi Francs, FBu) for the public and NGO markets, and 3.5-fold higher in the private sector (US$0.56 or 700 FBu). Quinine tablets were similarly priced in the public (US$1.53 or 1,892.50 FBu), private and NGO sectors (both US$1.61 or 2,000 FBu). Non-policy anti-malarials were priced 50-fold higher than the price of AS-AQ in the public sector. A course of AS-AQ was affordable at 0.4 of a day's wage in the public and NGO sectors, whereas, it was

  14. Anti-malarial treatment outcomes in Ethiopia: a systematic review and meta-analysis.

    PubMed

    Gebreyohannes, Eyob Alemayehu; Bhagavathula, Akshaya Srikanth; Seid, Mohammed Assen; Tegegn, Henok Getachew

    2017-07-03

    Ethiopia is among countries with a high malaria burden. There are several studies that assessed the efficacy of anti-malarial agents in the country and this systematic review and meta-analysis was performed to obtain stronger evidence on treatment outcomes of malaria from the existing literature in Ethiopia. A systematic literature search using the preferred reporting items for systematic review and meta-analysis (PRISMA) statement was conducted on studies from Pubmed, Google Scholar, and ScienceDirect databases to identify published and unpublished literature. Comprehensive meta-analysis software was used to perform all meta-analyses. The Cochrane Q and the I (2) were used to evaluate heterogeneity of studies. Random effects model was used to combine studies showing heterogeneity of Cochrane Q p < 0.10 and I (2)  > 50. Twenty-one studies were included in the final analysis with a total number of 3123 study participants. Treatment outcomes were assessed clinically and parasitologically using World Health Organization guidelines. Adequate clinical and parasitological response was used to assess treatment success at the 28th day. Overall, a significant high treatment success of 92.9% (95% CI 89.1-96.6), p < 0.001, I (2)  = 98.39% was noticed. However, treatment success was higher in falciparum malaria patients treated with artemether-lumefantrine than chloroquine for Plasmodium vivax patients [98.1% (97.0-99.2), p < 0.001, I (2)  = 72.55 vs 94.7% (92.6-96.2), p < 0.001, I (2)  = 53.62%]. Seven studies reported the adverse drug reactions to anti-malarial treatment; of 822 participants, 344 of them were exposed to adverse drug reactions with a pooled event rate of 39.8% (14.1-65.5), p = 0.002. On the basis of this review, anti-malarial treatment success was high (92.9%) and standard regimens showed good efficacy against Plasmodium falciparum (98.1%) and P. vivax (94.7%) infections in Ethiopia, but associated with high rates of adverse drug reactions

  15. The association between price, competition, and demand factors on private sector anti-malarial stocking and sales in western Kenya: considerations for the AMFm subsidy

    PubMed Central

    2013-01-01

    Background Households in sub-Saharan Africa are highly reliant on the retail sector for obtaining treatment for malaria fevers and other illnesses. As donors and governments seek to promote the use of artemisinin combination therapy in malaria-endemic areas through subsidized anti-malarials offered in the retail sector, understanding the stocking and pricing decisions of retail outlets is vital. Methods A survey of all medicine retailers serving Bungoma East District in western Kenya was conducted three months after the launch of the AMFm subsidy in Kenya. The survey obtained information on each anti-malarial in stock: brand name, price, sales volume, outlet characteristics and GPS co-ordinates. These data were matched to household-level data from the Webuye Health and Demographic Surveillance System, from which population density and fever prevalence near each shop were determined. Regression analysis was used to identify the factors associated with retailers’ likelihood of stocking subsidized artemether lumefantrine (AL) and the association between price and sales for AL, quinine and sulphadoxine-pyrimethamine (SP). Results Ninety-seven retail outlets in the study area were surveyed; 11% of outlets stocked subsidized AL. Size of the outlet and having a pharmacist on staff were associated with greater likelihood of stocking subsidized AL. In the multivariable model, total volume of anti-malarial sales was associated with greater likelihood of stocking subsidized AL and competition was important; likelihood of stocking subsidized AL was considerably higher if the nearest neighbour stocked subsidized AL. Price was a significant predictor of sales volume for all three types of anti-malarials but the relationship varied, with the largest price sensitivity found for SP drugs. Conclusion The results suggest that helping small outlets overcome the constraints to stocking subsidized AL should be a priority. Competition between retailers and prices can play an important

  16. The association between price, competition, and demand factors on private sector anti-malarial stocking and sales in western Kenya: considerations for the AMFm subsidy.

    PubMed

    O'Meara, Wendy Prudhomme; Obala, Andrew; Thirumurthy, Harsha; Khwa-Otsyula, Barasa

    2013-06-05

    Households in sub-Saharan Africa are highly reliant on the retail sector for obtaining treatment for malaria fevers and other illnesses. As donors and governments seek to promote the use of artemisinin combination therapy in malaria-endemic areas through subsidized anti-malarials offered in the retail sector, understanding the stocking and pricing decisions of retail outlets is vital. A survey of all medicine retailers serving Bungoma East District in western Kenya was conducted three months after the launch of the AMFm subsidy in Kenya. The survey obtained information on each anti-malarial in stock: brand name, price, sales volume, outlet characteristics and GPS co-ordinates. These data were matched to household-level data from the Webuye Health and Demographic Surveillance System, from which population density and fever prevalence near each shop were determined. Regression analysis was used to identify the factors associated with retailers' likelihood of stocking subsidized artemether lumefantrine (AL) and the association between price and sales for AL, quinine and sulphadoxine-pyrimethamine (SP). Ninety-seven retail outlets in the study area were surveyed; 11% of outlets stocked subsidized AL. Size of the outlet and having a pharmacist on staff were associated with greater likelihood of stocking subsidized AL. In the multivariable model, total volume of anti-malarial sales was associated with greater likelihood of stocking subsidized AL and competition was important; likelihood of stocking subsidized AL was considerably higher if the nearest neighbour stocked subsidized AL. Price was a significant predictor of sales volume for all three types of anti-malarials but the relationship varied, with the largest price sensitivity found for SP drugs. The results suggest that helping small outlets overcome the constraints to stocking subsidized AL should be a priority. Competition between retailers and prices can play an important role in greater adoption of AL.

  17. In Silico and In Vivo Anti-Malarial Studies of 18β Glycyrrhetinic Acid from Glycyrrhiza glabra

    PubMed Central

    Kalani, Komal; Agarwal, Jyoti; Alam, Sarfaraz; Khan, Feroz; Pal, Anirban; Srivastava, Santosh Kumar

    2013-01-01

    Malaria is one of the most prevailing fatal diseases causing between 1.2 and 2.7 million deaths all over the world each year. Further, development of resistance against the frontline anti-malarial drugs has created an alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-malarial agents possessing novel modes of action. Over the past few years triterpenoids from higher plants have shown a wide range of anti-malarial activities. As a part of our drug discovery program for anti-malarial agents from Indian medicinal plants, roots of Glycyrrhizaglabra were chemically investigated, which resulted in the isolation and characterization of 18β-glycyrrhetinic acid (GA) as a major constituent. The in vitro studies against P. falciparum showed significant (IC50 1.69µg/ml) anti-malarial potential for GA. Similarly, the molecular docking studies showed adequate docking (LibDock) score of 71.18 for GA and 131.15 for standard anti-malarial drug chloroquine. Further, in silico pharmacokinetic and drug-likeness studies showed that GA possesses drug-like properties. Finally, in vivo evaluation showed a dose dependent anti-malarial activity ranging from 68–100% at doses of 62.5–250mg/kg on day 8. To the best of our knowledge this is the first ever report on the anti-malarial potential of GA. Further work on optimization of the anti-malarial lead is under progress. PMID:24086367

  18. Tafenoquine and NPC-1161B require CYP 2D metabolism for anti-malarial activity: implications for the 8-aminoquinoline class of anti-malarial compounds

    PubMed Central

    2014-01-01

    Background Tafenoquine (TQ) is an 8-aminoquinoline (8AQ) that has been tested in several Phase II and Phase III clinical studies and is currently in late stage development as an anti-malarial prophylactic agent. NPC-1161B is a promising 8AQ in late preclinical development. It has recently been reported that the 8AQ drug primaquine requires metabolic activation by CYP 2D6 for efficacy in humans and in mice, highlighting the importance of pharmacogenomics in the target population when administering primaquine. A logical follow-up study was to determine whether CYP 2D activation is required for other compounds in the 8AQ structural class. Methods In the present study, the anti-malarial activities of NPC-1161B and TQ were assessed against luciferase expressing Plasmodium berghei in CYP 2D knock-out mice in comparison with normal C57BL/6 mice (WT) and with humanized/CYP 2D6 knock-in mice by monitoring luminescence with an in vivo imaging system. These experiments were designed to determine the direct effects of CYP 2D metabolic activation on the anti-malarial efficacy of NPC-1161B and TQ. Results NPC-1161B and TQ exhibited no anti-malarial activity in CYP 2D knock-out mice when dosed at their ED100 values (1 mg/kg and 3 mg/kg, respectively) established in WT mice. TQ anti-malarial activity was partially restored in humanized/CYP 2D6 knock-in mice when tested at two times its ED100. Conclusions The results reported here strongly suggest that metabolism of NPC-1161B and TQ by the CYP 2D enzyme class is essential for their anti-malarial activity. Furthermore, these results may provide a possible explanation for therapeutic failures for patients who do not respond to 8AQ treatment for relapsing malaria. Because CYP 2D6 is highly polymorphic, variable expression of this enzyme in humans represents a significant pharmacogenomic liability for 8AQs which require CYP 2D metabolic activation for efficacy, particularly for large-scale prophylaxis and eradication campaigns. PMID

  19. Tafenoquine and NPC-1161B require CYP 2D metabolism for anti-malarial activity: implications for the 8-aminoquinoline class of anti-malarial compounds.

    PubMed

    Marcsisin, Sean R; Sousa, Jason C; Reichard, Gregory A; Caridha, Diana; Zeng, Qiang; Roncal, Norma; McNulty, Ronan; Careagabarja, Julio; Sciotti, Richard J; Bennett, Jason W; Zottig, Victor E; Deye, Gregory; Li, Qigui; Read, Lisa; Hickman, Mark; Dhammika Nanayakkara, N P; Walker, Larry A; Smith, Bryan; Melendez, Victor; Pybus, Brandon S

    2014-01-03

    Tafenoquine (TQ) is an 8-aminoquinoline (8AQ) that has been tested in several Phase II and Phase III clinical studies and is currently in late stage development as an anti-malarial prophylactic agent. NPC-1161B is a promising 8AQ in late preclinical development. It has recently been reported that the 8AQ drug primaquine requires metabolic activation by CYP 2D6 for efficacy in humans and in mice, highlighting the importance of pharmacogenomics in the target population when administering primaquine. A logical follow-up study was to determine whether CYP 2D activation is required for other compounds in the 8AQ structural class. In the present study, the anti-malarial activities of NPC-1161B and TQ were assessed against luciferase expressing Plasmodium berghei in CYP 2D knock-out mice in comparison with normal C57BL/6 mice (WT) and with humanized/CYP 2D6 knock-in mice by monitoring luminescence with an in vivo imaging system. These experiments were designed to determine the direct effects of CYP 2D metabolic activation on the anti-malarial efficacy of NPC-1161B and TQ. NPC-1161B and TQ exhibited no anti-malarial activity in CYP 2D knock-out mice when dosed at their ED100 values (1 mg/kg and 3 mg/kg, respectively) established in WT mice. TQ anti-malarial activity was partially restored in humanized/CYP 2D6 knock-in mice when tested at two times its ED100. The results reported here strongly suggest that metabolism of NPC-1161B and TQ by the CYP 2D enzyme class is essential for their anti-malarial activity. Furthermore, these results may provide a possible explanation for therapeutic failures for patients who do not respond to 8AQ treatment for relapsing malaria. Because CYP 2D6 is highly polymorphic, variable expression of this enzyme in humans represents a significant pharmacogenomic liability for 8AQs which require CYP 2D metabolic activation for efficacy, particularly for large-scale prophylaxis and eradication campaigns.

  20. Therapeutic indications and other use-case-driven updates in the drug ontology: anti-malarials, anti-hypertensives, opioid analgesics, and a large term request.

    PubMed

    Hogan, William R; Hanna, Josh; Hicks, Amanda; Amirova, Samira; Bramblett, Baxter; Diller, Matthew; Enderez, Rodel; Modzelewski, Timothy; Vasconcelos, Mirela; Delcher, Chris

    2017-03-03

    The Drug Ontology (DrOn) is an OWL2-based representation of drug products and their ingredients, mechanisms of action, strengths, and dose forms. We originally created DrOn for use cases in comparative effectiveness research, primarily to identify historically complete sets of United States National Drug Codes (NDCs) that represent packaged drug products, by the ingredient(s), mechanism(s) of action, and so on contained in those products. Although we had designed DrOn from the outset to carefully distinguish those entities that have a therapeutic indication from those entities that have a molecular mechanism of action, we had not previously represented in DrOn any particular therapeutic indication. In this work, we add therapeutic indications for three research use cases: resistant hypertension, malaria, and opioid abuse research. We also added mechanisms of action for opioid analgesics and added 108 classes representing drug products in response to a large term request from the Program for Resistance, Immunology, Surveillance and Modeling of Malaria in Uganda (PRISM) project. The net result is a new version of DrOn, current to May 2016, that represents three major therapeutic classes of drugs and six new mechanisms of action. A therapeutic indication of a drug product is represented as a therapeutic function in DrOn. Adverse effects of drug products, as well as other therapeutic uses for which the drug product was not designed are dispositions. Our work provides a framework for representing additional therapeutic indications, adverse effects, and uses of drug products beyond their design. Our work also validated our past modeling decisions for specific types of mechanisms of action, namely effects mediated via receptor and/or enzyme binding. DrOn is available at: http://purl.obolibrary.org/obo/dron.owl . A smaller version without NDCs is available at: http://purl.obolibrary.org/obo/dron/dron-lite.owl.

  1. Poor quality vital anti-malarials in Africa - an urgent neglected public health priority

    PubMed Central

    2011-01-01

    Background Plasmodium falciparum malaria remains a major public health problem. A vital component of malaria control rests on the availability of good quality artemisinin-derivative based combination therapy (ACT) at the correct dose. However, there are increasing reports of poor quality anti-malarials in Africa. Methods Seven collections of artemisinin derivative monotherapies, ACT and halofantrine anti-malarials of suspicious quality were collected in 2002/10 in eleven African countries and in Asia en route to Africa. Packaging, chemical composition (high performance liquid chromatography, direct ionization mass spectrometry, X-ray diffractometry, stable isotope analysis) and botanical investigations were performed. Results Counterfeit artesunate containing chloroquine, counterfeit dihydroartemisinin (DHA) containing paracetamol (acetaminophen), counterfeit DHA-piperaquine containing sildenafil, counterfeit artemether-lumefantrine containing pyrimethamine, counterfeit halofantrine containing artemisinin, and substandard/counterfeit or degraded artesunate and artesunate+amodiaquine in eight countries are described. Pollen analysis was consistent with manufacture of counterfeits in eastern Asia. These data do not allow estimation of the frequency of poor quality anti-malarials in Africa. Conclusions Criminals are producing diverse harmful anti-malarial counterfeits with important public health consequences. The presence of artesunate monotherapy, substandard and/or degraded and counterfeit medicines containing sub-therapeutic amounts of unexpected anti-malarials will engender drug resistance. With the threatening spread of artemisinin resistance to Africa, much greater investment is required to ensure the quality of ACTs and removal of artemisinin monotherapies. The International Health Regulations may need to be invoked to counter these serious public health problems. PMID:22152094

  2. Increased pfmdr1 gene copy number and the decline in pfcrt and pfmdr1 resistance alleles in Ghanaian Plasmodium falciparum isolates after the change of anti-malarial drug treatment policy.

    PubMed

    Duah, Nancy O; Matrevi, Sena A; de Souza, Dziedzom K; Binnah, Daniel D; Tamakloe, Mary M; Opoku, Vera S; Onwona, Christiana O; Narh, Charles A; Quashie, Neils B; Abuaku, Benjamin; Duplessis, Christopher; Kronmann, Karl C; Koram, Kwadwo A

    2013-10-30

    With the introduction of artemisinin-based combination therapy (ACT) in 2005, monitoring of anti-malarial drug efficacy, which includes the use of molecular tools to detect known genetic markers of parasite resistance, is important for first-hand information on the changes in parasite susceptibility to drugs in Ghana. This study investigated the Plasmodium falciparum multidrug resistance gene (pfmdr1) copy number, mutations and the chloroquine resistance transporter gene (pfcrt) mutations in Ghanaian isolates collected in seven years to detect the trends in prevalence of mutations. Archived filter paper blood blots collected from children aged below five years with uncomplicated malaria in 2003-2010 at sentinel sites were used. Using quantitative real-time polymerase chain reaction (qRT-PCR), 756 samples were assessed for pfmdr1 gene copy number. PCR and restriction fragment length polymorphism (RFLP) were used to detect alleles of pfmdr1 86 in 1,102 samples, pfmdr1 184, 1034, 1042 and 1246 in 832 samples and pfcrt 76 in 1,063 samples. Merozoite surface protein 2 (msp2) genotyping was done to select monoclonal infections for copy number analysis. The percentage of isolates with increased pfmdr1 copy number were 4, 27, 9, and 18% for 2003-04, 2005-06, 2007-08 and 2010, respectively. Significant increasing trends for prevalence of pfmdr1 N86 (×(2) = 96.31, p <0.001) and pfcrt K76 (×(2) = 64.50, p <0.001) and decreasing trends in pfmdr1 Y86 (x(2) = 38.52, p <0.001) and pfcrt T76 (x(2) = 43.49, p <0.001) were observed from 2003-2010. The pfmdr1 F184 and Y184 prevalence showed an increasing and decreasing trends respectively but were not significant (×(2) = 7.39,p=0.060; ×(2) = 7.49, p = 0.057 respectively). The pfmdr1 N86-F184-D1246 haplotype, which is alleged to be selected by artemether-lumefantrine showed a significant increasing trend (×(2) = 20.75, p < 0.001). Increased pfmdr1 gene copy number was observed in the isolates analysed and this finding has

  3. The counterfeit anti-malarial is a crime against humanity: a systematic review of the scientific evidence

    PubMed Central

    2014-01-01

    Background The counterfeiting of anti-malarials represents a form of attack on global public health in which fake and substandard anti-malarials serve as de facto weapons of mass destruction, particularly in resource-constrained endemic settings, where malaria causes nearly 660,000 preventable deaths and threatens millions of lives annually. It has been estimated that fake anti-malarials contribute to nearly 450,000 preventable deaths every year. This crime against humanity is often underestimated or ignored. This study attempts to describe and characterize the direct and indirect effects of counterfeit anti-malarials on public health, clinical care and socio-economic conditions. Methods A search was performed using key databases, WHO documents, and English language search engines. Of 262 potential articles that were identified using a fixed set of criteria, a convenience sample of 105 appropriate articles was selected for this review. Results Artemisinin-based combination therapy (ACT) is an important tool in the fight against malaria, but a sizable number of patients are unable to afford to this first-line treatment. Consequently, patients tend to procure cheaper anti-malarials, which may be fake or substandard. Forensic palynology reveals that counterfeits originate in Asia. Fragile drug regulations, ineffective law-enforcement agencies and corruption further burden ailing healthcare facilities. Substandard/fake anti-malarials can cause (a) economic sabotage; (b) therapeutic failure; (c) increased risk of the emergence and spread of resistant strains of Plasmodium falciparum and Plasmodium vivax; (d) an undermining of trust/confidence in healthcare stakeholders/systems; and, (e) serious side effects or death. Conclusion Combating counterfeit anti-malarials is a complex task due to limited resources and poor techniques for the detection and identification of fake anti-malarials. This situation calls for sustainable, global, scientific research and policy change

  4. The impact of rapid malaria diagnostic tests upon anti-malarial sales in community pharmacies in Gwagwalada, Nigeria

    PubMed Central

    2013-01-01

    Background Rapid diagnostics tests for malaria (RDT) have become established as a practical solution to the challenges of parasitological confirmation of malaria before treatment in the public sector. However, little is known of their impact in private health sector facilities, such as pharmacies and drug shops. This study aimed to assess the incidence of malaria among unwell patients seeking anti-malarial treatment in two community pharmacies in Nigeria and measure the impact RDTs have on anti-malarial sales. Methods This was a comparison study of two pharmacies located in the suburbs of Gwagwalada, in the Federal Capital Territory of Nigeria, between May and July 2012. In the intervention arm, patients seeking to purchase anti-malarials had an RDT performed before treatment while the control pharmacy continued normal routine practice. Results A total of 1,226 participants were enrolled into the study. The incidence of malaria in the intervention arm (n = 619) was 13.6% and adolescent participants had a statistically significant higher incidence (26.0%) compared to adults (11.9%) (P = 0.001). A history of fever in the last 48 hours was associated with a statistically significant higher incidence of malaria (28.3%) (P < 0.001). Having a RDT test reduced the chance of purchasing an anti-malarial by 42% (95% CI: 38%-46%) compared to not having a test. 51.6% (276) of the study participants with a RDT negative result still purchased anti-malarials, especially if anti-malarials had been recommended by a health professional (58.9%) compared to self-referral (44.2%) (P = 0.001). Patients with RDT negative results were also more likely to purchase an anti-malarial if there was a reported malaria positive laboratory test prior to presentation (66.2%; P = 0.007), a history of fever in the last 48 hours (60.5%; P = 0.027), and primary school education or less (69.4%; P = 0.009). After adjusting for age group and gender differences, having at

  5. The impact of rapid malaria diagnostic tests upon anti-malarial sales in community pharmacies in Gwagwalada, Nigeria.

    PubMed

    Ikwuobe, John O; Faragher, Brian E; Alawode, Gafar; Lalloo, David G

    2013-10-30

    Rapid diagnostics tests for malaria (RDT) have become established as a practical solution to the challenges of parasitological confirmation of malaria before treatment in the public sector. However, little is known of their impact in private health sector facilities, such as pharmacies and drug shops. This study aimed to assess the incidence of malaria among unwell patients seeking anti-malarial treatment in two community pharmacies in Nigeria and measure the impact RDTs have on anti-malarial sales. This was a comparison study of two pharmacies located in the suburbs of Gwagwalada, in the Federal Capital Territory of Nigeria, between May and July 2012. In the intervention arm, patients seeking to purchase anti-malarials had an RDT performed before treatment while the control pharmacy continued normal routine practice. A total of 1,226 participants were enrolled into the study. The incidence of malaria in the intervention arm (n = 619) was 13.6% and adolescent participants had a statistically significant higher incidence (26.0%) compared to adults (11.9%) (P = 0.001). A history of fever in the last 48 hours was associated with a statistically significant higher incidence of malaria (28.3%) (P < 0.001). Having a RDT test reduced the chance of purchasing an anti-malarial by 42% (95% CI: 38%-46%) compared to not having a test. 51.6% (276) of the study participants with a RDT negative result still purchased anti-malarials, especially if anti-malarials had been recommended by a health professional (58.9%) compared to self-referral (44.2%) (P = 0.001). Patients with RDT negative results were also more likely to purchase an anti-malarial if there was a reported malaria positive laboratory test prior to presentation (66.2%; P = 0.007), a history of fever in the last 48 hours (60.5%; P = 0.027), and primary school education or less (69.4%; P = 0.009). After adjusting for age group and gender differences, having at least a secondary school education reduced the chance of

  6. In vitro and in vivo anti-malarial activity of plants from the Brazilian Amazon.

    PubMed

    Lima, Renata B S; Rocha e Silva, Luiz F; Melo, Marcia R S; Costa, Jaqueline S; Picanço, Neila S; Lima, Emerson S; Vasconcellos, Marne C; Boleti, Ana Paula A; Santos, Jakeline M P; Amorim, Rodrigo C N; Chaves, Francisco C M; Coutinho, Julia P; Tadei, Wanderli P; Krettli, Antoniana U; Pohlit, Adrian M

    2015-12-18

    The anti-malarials quinine and artemisinin were isolated from traditionally used plants (Cinchona spp. and Artemisia annua, respectively). The synthetic quinoline anti-malarials (e.g. chloroquine) and semi-synthetic artemisinin derivatives (e.g. artesunate) were developed based on these natural products. Malaria is endemic to the Amazon region where Plasmodium falciparum and Plasmodium vivax drug-resistance is of concern. There is an urgent need for new anti-malarials. Traditionally used Amazonian plants may provide new treatments for drug-resistant P. vivax and P. falciparum. Herein, the in vitro and in vivo antiplasmodial activity and cytotoxicity of medicinal plant extracts were investigated. Sixty-nine extracts from 11 plant species were prepared and screened for in vitro activity against P. falciparum K1 strain and for cytotoxicity against human fibroblasts and two melanoma cell lines. Median inhibitory concentrations (IC50) were established against chloroquine-resistant P. falciparum W2 clone using monoclonal anti-HRPII (histidine-rich protein II) antibodies in an enzyme-linked immunosorbent assay. Extracts were evaluated for toxicity against murine macrophages (IC50) and selectivity indices (SI) were determined. Three extracts were also evaluated orally in Plasmodium berghei-infected mice. High in vitro antiplasmodial activity (IC50 = 6.4-9.9 µg/mL) was observed for Andropogon leucostachyus aerial part methanol extracts, Croton cajucara red variety leaf chloroform extracts, Miconia nervosa leaf methanol extracts, and Xylopia amazonica leaf chloroform and branch ethanol extracts. Paullinia cupana branch chloroform extracts and Croton cajucara red variety leaf ethanol extracts were toxic to fibroblasts and or melanoma cells. Xylopia amazonica branch ethanol extracts and Zanthoxylum djalma-batistae branch chloroform extracts were toxic to macrophages (IC50 = 6.9 and 24.7 µg/mL, respectively). Andropogon leucostachyus extracts were the most selective (SI >28

  7. Development of a genetic tool for functional screening of anti-malarial bioactive extracts in metagenomic libraries.

    PubMed

    Mongui, Alvaro; Pérez-Llanos, Francy J; Yamamoto, Marcio M; Lozano, Marcela; Zambrano, Maria M; Del Portillo, Patricia; Fernández-Becerra, Carmen; Restrepo, Silvia; Del Portillo, Hernando A; Junca, Howard

    2015-06-04

    The chemical treatment of Plasmodium falciparum for human infections is losing efficacy each year due to the rise of resistance. One possible strategy to find novel anti-malarial drugs is to access the largest reservoir of genomic biodiversity source on earth present in metagenomes of environmental microbial communities. A bioluminescent P. falciparum parasite was used to quickly detect shifts in viability of microcultures grown in 96-well plates. A synthetic gene encoding the Dermaseptin 4 peptide was designed and cloned under tight transcriptional control in a large metagenomic insert context (30 kb) to serve as proof-of-principle for the screening platform. Decrease in parasite viability consistently correlated with bioluminescence emitted from parasite microcultures, after their exposure to bacterial extracts containing a plasmid or fosmid engineered to encode the Dermaseptin 4 anti-malarial peptide. Here, a new technical platform to access the anti-malarial potential in microbial environmental metagenomes has been developed.

  8. New developments in anti-malarial target candidate and product profiles.

    PubMed

    Burrows, Jeremy N; Duparc, Stephan; Gutteridge, Winston E; Hooft van Huijsduijnen, Rob; Kaszubska, Wiweka; Macintyre, Fiona; Mazzuri, Sébastien; Möhrle, Jörg J; Wells, Timothy N C

    2017-01-13

    A decade of discovery and development of new anti-malarial medicines has led to a renewed focus on malaria elimination and eradication. Changes in the way new anti-malarial drugs are discovered and developed have led to a dramatic increase in the number and diversity of new molecules presently in pre-clinical and early clinical development. The twin challenges faced can be summarized by multi-drug resistant malaria from the Greater Mekong Sub-region, and the need to provide simplified medicines. This review lists changes in anti-malarial target candidate and target product profiles over the last 4 years. As well as new medicines to treat disease and prevent transmission, there has been increased focus on the longer term goal of finding new medicines for chemoprotection, potentially with long-acting molecules, or parenteral formulations. Other gaps in the malaria armamentarium, such as drugs to treat severe malaria and endectocides (that kill mosquitoes which feed on people who have taken the drug), are defined here. Ultimately the elimination of malaria requires medicines that are safe and well-tolerated to be used in vulnerable populations: in pregnancy, especially the first trimester, and in those suffering from malnutrition or co-infection with other pathogens. These updates reflect the maturing of an understanding of the key challenges in producing the next generation of medicines to control, eliminate and ultimately eradicate malaria.

  9. Access to Artemisinin-Combination Therapy (ACT) and other Anti-Malarials: National Policy and Markets in Sierra Leone

    PubMed Central

    Amuasi, John H.; Diap, Graciela; Nguah, Samuel Blay; Karikari, Patrick; Boakye, Isaac; Jambai, Amara; Lahai, Wani Kumba; Louie, Karly S.; Kiechel, Jean-Rene

    2012-01-01

    Malaria remains the leading burden of disease in post-conflict Sierra Leone. To overcome the challenge of anti-malarial drug resistance and improve effective treatment, Sierra Leone adopted artemisinin-combination therapy artesunate-amodiaquine (AS+AQ) as first-line treatment for uncomplicated P. falciparum malaria. Other national policy anti-malarials include artemether-lumefantrine (AL) as an alternative to AS+AQ, quinine and artemether for treatment of complicated malaria; and sulphadoxine-pyrimethamine (SP) for intermittent preventive treatment (IPTp). This study was conducted to evaluate access to national policy recommended anti-malarials. A cross-sectional survey of 127 medicine outlets (public, private and NGO) was conducted in urban and rural areas. The availability on the day of the survey, median prices, and affordability policy and available non-policy anti-malarials were calculated. Anti-malarials were stocked in 79% of all outlets surveyed. AS+AQ was widely available in public medicine outlets; AL was only available in the private and NGO sectors. Quinine was available in nearly two-thirds of public and NGO outlets and over one-third of private outlets. SP was widely available in all outlets. Non-policy anti-malarials were predominantly available in the private outlets. AS+AQ in the public sector was widely offered for free. Among the anti-malarials sold at a cost, the same median price of a course of AS+AQ (US$1.56), quinine tablets (US$0.63), were found in both the public and private sectors. Quinine injection had a median cost of US$0.31 in the public sector and US$0.47 in the private sector, while SP had a median cost of US$0.31 in the public sector compared to US$ 0.63 in the private sector. Non-policy anti-malarials were more affordable than first-line AS+AQ in all sectors. A course of AS+AQ was affordable at nearly two days’ worth of wages in both the public and private sectors. PMID:23133522

  10. Anti-malarial activity of Holarrhena antidysenterica and Viola canescens, plants traditionally used against malaria in the Garhwal region of north-west Himalaya

    PubMed Central

    2011-01-01

    Background The increasing number of multidrug-resistant Plasmodium strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from Artemisia annua. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine. Methods In vitro anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive Plasmodium berghei NK65 strain in Swiss albino mice was used for monitoring in vivo activity of plant extracts. Results Chloroform extract of H. antidysenterica (HA-2) and petroleum ether extract of V. canescens (VC-1) plants significantly reduced parasitaemia in P. berghei infected mice. The extract HA-2 showed in vitro anti-plasmodial activity with its IC50 value 5.5 μg/ml using pLDH assay and ED50 value 18.29 mg/kg in P. berghei infected Swiss albino mice. Similarly petroleum ether extract of V. canescens (VC-1) showed in vitro anti-plasmodial activity with its IC50 value 2.76 μg/ml using pLDH assay and ED50 15.8 mg/kg in P. berghei infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of V. canescens was found slightly cytotoxic. Conclusion The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria. PMID:21288335

  11. Anti-malarial activity of Holarrhena antidysenterica and Viola canescens, plants traditionally used against malaria in the Garhwal region of north-west Himalaya.

    PubMed

    Verma, Gaurav; Dua, Virendra K; Agarwal, Dau Dayal; Atul, Pravin Kumar

    2011-02-02

    The increasing number of multidrug-resistant Plasmodium strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from Artemisia annua. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine. In vitro anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive Plasmodium berghei NK65 strain in Swiss albino mice was used for monitoring in vivo activity of plant extracts. Chloroform extract of H. antidysenterica (HA-2) and petroleum ether extract of V. canescens (VC-1) plants significantly reduced parasitaemia in P. berghei infected mice. The extract HA-2 showed in vitro anti-plasmodial activity with its IC50 value 5.5 μg/ml using pLDH assay and ED50 value 18.29 mg/kg in P. berghei infected Swiss albino mice. Similarly petroleum ether extract of V. canescens (VC-1) showed in vitro anti-plasmodial activity with its IC50 value 2.76 μg/ml using pLDH assay and ED50 15.8 mg/kg in P. berghei infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of V. canescens was found slightly cytotoxic. The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria.

  12. QSAR models for anti-malarial activity of 4-aminoquinolines.

    PubMed

    Masand, Vijay H; Toropov, Andrey A; Toropova, Alla P; Mahajan, Devidas T

    2014-03-01

    In the present study, predictive quantitative structure - activity relationship (QSAR) models for anti-malarial activity of 4-aminoquinolines have been developed. CORAL, which is freely available on internet (http://www.insilico.eu/coral), has been used as a tool of QSAR analysis to establish statistically robust QSAR model of anti-malarial activity of 4-aminoquinolines. Six random splits into the visible sub-system of the training and invisible subsystem of validation were examined. Statistical qualities for these splits vary, but in all these cases, statistical quality of prediction for anti-malarial activity was quite good. The optimal SMILES-based descriptor was used to derive the single descriptor based QSAR model for a data set of 112 aminoquinolones. All the splits had r(2)> 0.85 and r(2)> 0.78 for subtraining and validation sets, respectively. The three parametric multilinear regression (MLR) QSAR model has Q(2) = 0.83, R(2) = 0.84 and F = 190.39. The anti-malarial activity has strong correlation with presence/absence of nitrogen and oxygen at a topological distance of six.

  13. Review of pyronaridine anti-malarial properties and product characteristics

    PubMed Central

    2012-01-01

    Pyronaridine was synthesized in 1970 at the Institute of Chinese Parasitic Disease and has been used in China for over 30 years for the treatment of malaria. Pyronaridine has high potency against Plasmodium falciparum, including chloroquine-resistant strains. Studies in various animal models have shown pyronaridine to be effective against strains resistant to other anti-malarials, including chloroquine. Resistance to pyronaridine appears to emerge slowly and is further retarded when pyronaridine is used in combination with other anti-malarials, in particular, artesunate. Pyronaridine toxicity is generally less than that of chloroquine, though evidence of embryotoxicity in rodents suggests use with caution in pregnancy. Clinical pharmacokinetic data for pyronaridine indicates an elimination T1/2 of 13.2 and 9.6 days, respectively, in adults and children with acute uncomplicated falciparum and vivax malaria in artemisinin-combination therapy. Clinical data for mono or combined pyronaridine therapy show excellent anti-malarial effects against P. falciparum and studies of combination therapy also show promise against Plasmodium vivax. Pyronaridine has been developed as a fixed dose combination therapy, in a 3:1 ratio, with artesunate for the treatment of acute uncomplicated P. falciparum malaria and blood stage P. vivax malaria with the name of Pyramax® and has received Positive Opinion by European Medicines Agency under the Article 58 procedure. PMID:22877082

  14. Recent progress in the identification and development of anti-malarial agents using virtual screening based approaches.

    PubMed

    Shah, Priyanka; Tiwari, Sunita; Siddiqi, Mohammad Imran

    2015-01-01

    Malaria has continued to be one of the most perplexing diseases for biological science community around the world due to its prevalent devastating nature and quick developing resistance against the frontline drugs. Artimisinin-based combination therapy (ACT) has been so far found to be among the best therapies against Plasmodium pathogens but alarming emergence of resistance in parasites against every known chemotherapy has prompted the scientific community to step up all the efforts towards development of new and affordable anti-malarial drugs. Computer-aided approaches have received enormous attention in recent years in the field of identification and design of novel drugs. In this review, we summarize recently published research concerning the identification and development of anti-malarial compounds using virtual screening approaches. It would be admirable to discern the successful application of in silico studies for anti-malarial drug discovery hitherto and would certainly help in generating new avenues for pursuing integrated studies between the experimentalists and computational chemists in a systematic manner as a time and cost efficient alternative for future antimalarial drug discovery projects.

  15. Anti-malarial market and policy surveys in sub-Saharan Africa.

    PubMed

    Diap, Graciela; Amuasi, John; Boakye, Isaac; Sevcsik, Ann-Marie; Pecoul, Bernard

    2010-04-23

    At a recent meeting (Sept 18, 2009) in which reasons for the limited access to artemisinin-based combination therapy (ACT) in sub-Saharan Africa were discussed, policy and market surveys on anti-malarial drug availability and accessibility in Burundi and Sierra Leone were presented in a highly interactive brainstorming session among key stakeholders across private, public, and not-for-profit sectors. The surveys, the conduct of which directly involved the national malaria control programme managers of the two countries, provides the groundwork for evidence-based policy implementation. The results of the surveys could be extrapolated to other countries with similar socio-demographic and malaria profiles. The meeting resulted in recommendations on key actions to be taken at the global, national, and community level for better ACT accessibility. At the global level, both public and private sectors have actions to take to strengthen policies that lead to the replacement of loose blister packs with fixed-dose ACT products, develop strategies to ban inappropriate anti-malarials and regulate those bans, and facilitate technology and knowledge transfer to scale up production of fixed-dose ACT products, which should be readily available and affordable to those patients who are in the greatest need of these medicines. At the national level, policies that regulate the anti-malarial medicines market should be enacted and enforced. The public sector, including funding donors, should participate in ensuring that the private sector is engaged in the ACT implementation process. Research similar to the surveys discussed is important for other countries to develop and evaluate the right incentives at a local level. At the community level, community outreach and education about appropriate preventive and treatment measures must continue and be strengthened, with service delivery systems developed within both public and private sectors, among other measures, to decrease access to

  16. The in vitro anti-plasmodial and in vivo anti-malarial efficacy of combinations of some medicinal plants used traditionally for treatment of malaria by the Meru community in Kenya.

    PubMed

    Gathirwa, J W; Rukunga, G M; Njagi, E N M; Omar, S A; Mwitari, P G; Guantai, A N; Tolo, F M; Kimani, C W; Muthaura, C N; Kirira, P G; Ndunda, T N; Amalemba, G; Mungai, G M; Ndiege, I O

    2008-01-17

    The use of herbal drugs as combinations has existed for centuries in several cultural systems. However, the safety and efficacy of such combinations have not been validated. In this study, the toxicity, anti-plasmodial and antimalarial efficacy of several herbal drug combinations were investigated. Lannea schweinfurthii, Turraea robusta and Sclerocarya birrea, used by traditional health practitioners in Meru community, were tested for in vitro anti-plasmodial and in vivo anti-malarial activity singly against Plasmodium falciparum and Plasmodium berghei, respectively. Methanolic extract of Turraea robusta was the most active against Plasmodium falciparum D6 strain. Aqueous extracts of Lannea schweinfurthii had the highest anti-plamodial activity followed by Turraea robusta and Sclerocarya birrea. D6 was more sensitive to the plant extracts than W2 strain. Lannea schweinfurthii extracts had the highest anti-malarial activity in mice followed by Turraea robusta and Sclerocarya birrea with the methanol extracts being more active than aqueous ones. Combinations of aqueous extracts of the three plants and two others (Boscia salicifolia and Rhus natalensis) previously shown to exhibit anti-plasmodial and anti-malarial activity singly were tested in mice. Marked synergy and additive interactions were observed when combinations of the drugs were assayed in vitro. Different combinations of Turraea robusta and Lannea schweinfurthii exhibited good in vitro synergistic interactions. Combinations of Boscia salicifolia and Sclerocarya birrea; Rhus natalensis and Turraea robusta; Rhus natalensis and Boscia salicifolia; Turraea robusta and Sclerocarya birrea; and Lannea schweinfurthii and Boscia salicifolia exhibited high malaria parasite suppression (chemo-suppression >90%) in vivo when tested in mice. The findings are a preliminary demonstration of the usefulness of combining several plants in herbal drugs, as a normal practice of traditional health practitioners.

  17. Fourier transform infrared spectroscopy as a tool for identification of crude microbial extracts with anti-malarial potential.

    PubMed

    Sankarganesh, P; Joseph, Baby

    2016-01-01

    Fourier transform infrared (FT-IR) spectroscopy is an indispensable tool for identifying biologically active functional groups in uncharacterized crude samples. Here, using FT-IR spectrum analysis, we identified crude extracts of Streptomyces that have anti-malarial activities and conducted a statistical analysis of their spectra. Among the three crude microbial extracts tested herein, an aromatic amine C-N stretching functional group was observed in the spectra of Streptomyces sp. BJSG1 and BJSG4 crude extracts. These extracts showed promising activity against Plasmodium falciparum in vitro cultures with IC50 values of 0.5 for BJSG1 and 0.4μg/mL for BJSG4. The present results showed that FT-IR analysis is necessary for the primary analysis of unknown samples in anti-malarial drug development.

  18. Anti-malarials are anti-cancers and vice versa - one arrow two sparrows.

    PubMed

    Kundu, Chanakya Nath; Das, Sarita; Nayak, Anmada; Satapathy, Shakti Ranjan; Das, Dipon; Siddharth, Sumit

    2015-09-01

    Repurposing is the novel means of drug discovery in modern science due to its affordability, safety and availability. Here, we systematically discussed the efficacy and mode of action of multiple bioactive, synthetic compounds and their potential derivatives which are used to treat/prevent malaria and cancer. We have also discussed the detailed molecular pathway involved in anti-cancer potentiality of an anti-malarial drug and vice versa. Although the causative agents, pathophysiology and manifestation of both the diseases are different but special emphasis has been given on similar pathways governing disease manifestation and the drugs which act through deregulating those pathways. Finally, a future direction has been speculated to combat these two diseases by a single agent developed using nanotechnology. Extended combination and new formulation of existing drugs for one disease may lead to the discovery of drug for other diseases like an arrow for two sparrows. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Do ethnobotanical and laboratory data predict clinical safety and efficacy of anti-malarial plants?

    PubMed Central

    2011-01-01

    Background Over 1200 plant species are reported in ethnobotanical studies for the treatment of malaria and fevers, so it is important to prioritize plants for further development of anti-malarials. Methods The “RITAM score” was designed to combine information from systematic literature searches of published ethnobotanical studies and laboratory pharmacological studies of efficacy and safety, in order to prioritize plants for further research. It was evaluated by correlating it with the results of clinical trials. Results and discussion The laboratory efficacy score correlated with clinical parasite clearance (rs=0.7). The ethnobotanical component correlated weakly with clinical symptom clearance but not with parasite clearance. The safety component was difficult to validate as all plants entering clinical trials were generally considered safe, so there was no clinical data on toxic plants. Conclusion The RITAM score (especially the efficacy and safety components) can be used as part of the selection process for prioritising plants for further research as anti-malarial drug candidates. The validation in this study was limited by the very small number of available clinical studies, and the heterogeneity of patients included. PMID:21411018

  20. CoMFA, CoMSIA, and docking studies on thiolactone-class of potent anti-malarials: identification of essential structural features modulating anti-malarial activity.

    PubMed

    Roy, Kuldeep K; Bhunia, Shome S; Saxena, Anil K

    2011-09-01

    The integrated ligand- and structure-based drug design techniques have been applied on a homogeneous dataset of thiolactone-class of potent anti-malarials, to explore the essential structural features for the inhibition of Plasmodium falciparum. Developed CoMFA (q(2) = 0.716) and CoMSIA (q(2) = 0.632) models well explained structure-activity variation in both the training (CoMFA R(2) = 0.948 & CoMSIA R(2) = 0.849) and test set (CoMFA R(2) (pred) = 0.789 & CoMSIA R(2) (pred) = 0.733) compounds. The docking and scoring of the most active compound 10 into the active site of high-resolution (2.35 Å) structure of FabB-TLM binary complex (PDB-ID: 1FJ4) indicated that thiolactone core of this compound forms bifurcated H-bonding with two catalytic residues His298 and His333, and its saturated decyl side group is stabilized by hydrophobic interactions with the residues of a small hydrophobic groove, illustrating that the active site architecture, including two catalytic histidines and a small hydrophobic groove, is vital for protein-ligand interaction. In particular, the length and flexibility of the side group attached to the position 5 of thiolactone have been observed to play a significant role in the interaction with FabB enzyme. These results present scope for rational design of thiolactone-class of compounds that could furnish improved anti-malarial activity.

  1. Natural products as starting points for future anti-malarial therapies: going back to our roots?

    PubMed Central

    2011-01-01

    Background The discovery and development of new anti-malarials are at a crossroads. Fixed dose artemisinin combination therapy is now being used to treat a hundred million children each year, with a cost as low as 30 cents per child, with cure rates of over 95%. However, as with all anti-infective strategies, this triumph brings with it the seeds of its own downfall, the emergence of resistance. It takes ten years to develop a new medicine. New classes of medicines to combat malaria, as a result of infection by Plasmodium falciparum and Plasmodium vivax are urgently needed. Results Natural product scaffolds have been the basis of the majority of current anti-malarial medicines. Molecules such as quinine, lapachol and artemisinin were originally isolated from herbal medicinal products. After improvement with medicinal chemistry and formulation technologies, and combination with other active ingredients, they now make up the current armamentarium of medicines. In recent years advances in screening technologies have allowed testing of millions of compounds from pharmaceutical diversity for anti-malarial activity in cellular assays. These initiatives have resulted in thousands of new sub-micromolar active compounds – starting points for new drug discovery programmes. Against this backdrop, the paucity of potent natural products identified has been disappointing. Now is a good time to reflect on the current approach to screening herbal medicinal products and suggest revisions. Nearly sixty years ago, the Chinese doctor Chen Guofu, suggested natural products should be approached by dao-xing-ni-shi or ‘acting in the reversed order’, starting with observational clinical studies. Natural products based on herbal remedies are in use in the community, and have the potential unique advantage that clinical observational data exist, or can be generated. The first step should be the confirmation and definition of the clinical activity of herbal medicinal products already

  2. Geographically-weighted regression of knowledge and behaviour determinants to anti-malarial recommending and dispensing practice among medicine retailers in western Kenya: capacitating targeted interventions.

    PubMed

    Rusk, Andria; Highfield, Linda; Wilkerson, J Michael; Harrell, Melissa; Obala, Andrew; Amick, Benjamin

    2016-11-21

    Most patients with malaria seek treatment first in retail drug shops. Myriad studies have examined retailer behaviours and characteristics to understand the determinants to these behaviours. Geospatial methods are helpful in discovering if geographic location plays a role in the relationship between determinants and outcomes. This study aimed to discover if spatial autocorrelation exists in the relationship between determinants and retailer behaviours, and to provide specific geographic locations and target behaviours for tailoring future interventions. Retailer behaviours and characteristics captured from a survey deployed to medicine retailers in the Webuye Demographic and Health Surveillance Site were analysed using geographic weighted regression to create prediction models for three separate outcomes: recommending the first-line anti-malarial therapy to adults, recommending the first-line anti-malarial therapy to children, and selling that therapy more than other anti-malarials. The estimated regression coefficients for each determinant, as well as the pseudo R(2) values for each final model, were then mapped to assess spatial variability and local areas of best model fit. The relationships explored were found to be non-stationary, indicating that spatial heterogeneity exist in the data. The association between having a pharmacy-related health training and recommending the first-line anti-malarial treatment to adults was strongest around the peri-urban centre: comparing those with training in pharmacy to those without training (OR = 5.75, p = 0.021). The association between knowing the first-line anti-malarial and recommending it to children was strongest in the north of the study area compared to those who did not know the MOH-recommended anti-malarial (OR = 2.34, p = 0.070). This is also the area with the strongest association between attending a malaria workshop and selling the MOH-recommended anti-malarial more than other anti-malarials, compared to

  3. Differences in anti-malarial activity of 4-aminoalcohol quinoline enantiomers and investigation of the presumed underlying mechanism of action

    PubMed Central

    2012-01-01

    Background A better anti-malarial efficiency and lower neurotoxicity have been reported for mefloquine (MQ) (+)- enantiomer. However, the importance of stereoselectivity remains poorly understood as the anti-malarial activity of pure enantiomer MQ analogues has never been described. Building on these observations, a series of enantiopure 4-aminoalcohol quinoline derivatives has previously been synthesized to optimize the efficiency and reduce possible adverse effects. Their in vitro activity on Plasmodium falciparum W2 and 3D7 strains is reported here along with their inhibition of β-haematin formation and peroxidative degradation of haemin, two possible mechanisms of action of anti-malarial drugs. Results The (S)-enantiomers of this series of 4-aminoalcohol quinoline derivatives were found to be at least as effective as both chloroquine (CQ) and MQ. The derivative with a 5-carbon side-chain length was the more efficient on both P. falciparum strains. (R )-enantiomers displayed an activity decreased by 2 to 15-fold as compared to their (S) counterparts. The inhibition of β-haematin formation was significantly stronger with all tested compounds than with MQ, irrespective of the stereochemistry. Similarly, the inhibition of haemin peroxidation was significantly higher for both (S) and (R)-enantiomers of derivatives with a side-chain length of five or six carbons than for MQ and CQ. Conclusions The prominence of stereochemistry in the anti-malarial activity of 4-aminoalcohol quinoline derivatives is confirmed. The inhibition of β-haematin formation and haemin peroxidation can be put forward as presumed mechanisms of action but do not account for the stereoselectivity of action witnessed in vitro. PMID:22401346

  4. Potent in vivo anti-malarial activity and representative snapshot pharmacokinetic evaluation of artemisinin-quinoline hybrids

    PubMed Central

    2013-01-01

    Background Because Plasmodium falciparum displays increase tolerance against the recommended artemisinin combination therapies (ACT), new classes of anti-malarial drugs are urgently required. Previously synthesized artemisinin-aminoquinoline hybrids were evaluated to ascertain whether the potent low nanomolar in vitro anti-plasmodial activity would carry over in vivo against Plasmodium vinckei. A snapshot pharmacokinetic analysis was carried out on one of the hybrids to obtain an indication of the pharmacokinetic properties of this class of anti-malarial drugs. Methods In vitro activity of hybrids 2 and 3 were determined against the 3D7 strain of P. falciparum. Plasmodium vinckei-infected mice were treated with hybrids 1 – 3 for four days at a dosage of 0.8 mg/kg, 2.5 mg/kg, 7.5 mg/kg or 15 mg/kg intraperitoneally (ip), or orally (per os) with 2.7 mg/kg, 8.3 mg/kg, 25 mg/kg or 50 mg/kg. Artesunate was used as reference drug. A snapshot oral and IV pharmacokinetic study was performed on hybrid 2. Results Hybrids 1 – 3 displayed potent in vivo anti-malarial activity with ED50 of 1.1, 1.4 and <0.8 mg/kg by the ip route and 12, 16 and 13 mg/kg per os, respectively. Long-term monitoring of parasitaemia showed a complete cure of mice (without recrudescence) at 15 mg/kg via ip route and at 50 mg/kg by oral route for hybrid 1 and 2, whereas artesunate was only able to provide a complete cure at 30 mg/kg ip and 80 mg/kg per os. Conclusions These compounds provide a new class of desperately needed anti-malarial drug. Despite a short half-life and moderate oral bioavailability, this class of compounds was able to cure malaria in mice at very low dosages. The optimum linker length for anti-malarial activity was found to be a diaminoalkyl chain consisting of two carbon atoms either methylated or unmethylated. PMID:23433124

  5. Discovery of a selective, safe and novel anti-malarial compound with activity against chloroquine resistant strain of Plasmodium falciparum

    PubMed Central

    Agarwal, Ankita; Paliwal, Sarvesh; Mishra, Ruchi; Sharma, Swapnil; Kumar Dwivedi, Anil; Tripathi, Renu; Gunjan, Sarika

    2015-01-01

    In recent years the DNA minor groove has attracted much attention for the development of anti-malarial agents. In view of this we have attempted to discover novel DNA minor groove binders through in-silico and in-vitro workflow. A rigorously validated pharmacophore model comprising of two positive ionizable (PI), one hydrophobic (HY) and one ring aromatic (RA) features was used to mine NCI chemical compound database. This led to retrieval of many hits which were screened on the basis of estimated activity, fit value and Lipinski’s violation. Finally two compounds NSC639017 and NSC371488 were evaluated for their in-vitro anti-malarial activities against Plasmodium falciparum 3D7 (CQ sensitive) and K1 (CQ resistant) strains by SYBR green-I based fluorescence assay. The results revealed that out of two, NSC639017 posses excellent anti-malarial activity particularly against chloroquine resistant strain and moreover NSC639017 also appeared to be safe (CC50 126.04 μg/ml) and selective during cytotoxicity evaluation. PMID:26346444

  6. Anti-malarial Activities of Two Soil Actinomycete Isolates from Sabah via Inhibition of Glycogen Synthase Kinase 3β

    PubMed Central

    Dahari, Dhiana Efani; Salleh, Raifana Mohamad; Mahmud, Fauze; Chin, Lee Ping; Embi, Noor; Sidek, Hasidah Mohd

    2016-01-01

    Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition

  7. Anti-malarial activity and HS-SPME-GC-MS chemical profiling of Plinia cerrocampanensis leaf essential oil

    PubMed Central

    2014-01-01

    Background Plinia cerrocampanensis is an endemic plant of Panama. The leaf essential oil of this plant has shown antibacterial activity. However, anti-malarial activity and chemical profiling by HS-SPME-GC-MS of this essential oil have not been reported before. Methods Anti-malarial activity of the essential oil (EO) was evaluated in vitro against chloroquine-sensitive HB3 and chloroquine-resistant W2 strains of Plasmodium falciparum. Synergistic effect of chloroquine and the EO on parasite growth was evaluated by calculating the combination index. A methodology involving headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) was developed to investigate the composition of Plinia cerrocampanensis EO. Results Plinia cerrocampanensis EO showed a high anti-malarial activity and a synergistic interaction with chloroquine. The Plinia cerrocampanensis EO inhibited P. falciparum growth in vitro at an IC50 of 7.3 μg/mL. Chloroquine together with the EO decreased the IC50 of chloroquine from 0.1 μg/mL to 0.05 μg/mL, and of the EO from 7.3 μg/mL to 1.1 μg/mL. The measured combination index was 0.58, which clearly indicates that the EO acts synergistically with chloroquine. Since the EO maintained its inhibitory activity on the chloroquine-sensitive strain of the parasite, it could be acting by a different mechanism of action than chloroquine. The best HS-SPME-GC-MS analytical conditions were obtained when the temperature of extraction was 49°C, incubation time 14 min, and the time of extraction 10 min. This method allowed for the identification of 53 volatile constituents in the EO, including new compounds not reported earlier. Conclusions The anti-malarial activity exhibited by the Plinia cerrocampanensis EO may lend support for its possible use as an alternative for anti-malarial therapy. PMID:24410874

  8. Anti-malarial activity and HS-SPME-GC-MS chemical profiling of Plinia cerrocampanensis leaf essential oil.

    PubMed

    Durant, Armando A; Rodríguez, Candelario; Herrera, Liuris; Almanza, Alejandro; Santana, Ana I; Spadafora, Carmenza; Spadadora, Carmenza; Gupta, Mahabir P

    2014-01-13

    Plinia cerrocampanensis is an endemic plant of Panama. The leaf essential oil of this plant has shown antibacterial activity. However, anti-malarial activity and chemical profiling by HS-SPME-GC-MS of this essential oil have not been reported before. Anti-malarial activity of the essential oil (EO) was evaluated in vitro against chloroquine-sensitive HB3 and chloroquine-resistant W2 strains of Plasmodium falciparum. Synergistic effect of chloroquine and the EO on parasite growth was evaluated by calculating the combination index. A methodology involving headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) was developed to investigate the composition of Plinia cerrocampanensis EO. Plinia cerrocampanensis EO showed a high anti-malarial activity and a synergistic interaction with chloroquine. The Plinia cerrocampanensis EO inhibited P. falciparum growth in vitro at an IC50 of 7.3 μg/mL. Chloroquine together with the EO decreased the IC50 of chloroquine from 0.1 μg/mL to 0.05 μg/mL, and of the EO from 7.3 μg/mL to 1.1 μg/mL. The measured combination index was 0.58, which clearly indicates that the EO acts synergistically with chloroquine. Since the EO maintained its inhibitory activity on the chloroquine-sensitive strain of the parasite, it could be acting by a different mechanism of action than chloroquine. The best HS-SPME-GC-MS analytical conditions were obtained when the temperature of extraction was 49°C, incubation time 14 min, and the time of extraction 10 min. This method allowed for the identification of 53 volatile constituents in the EO, including new compounds not reported earlier. The anti-malarial activity exhibited by the Plinia cerrocampanensis EO may lend support for its possible use as an alternative for anti-malarial therapy.

  9. Awareness of anti-malarial policy and malaria treatment practices of patent medicine vendors in three Nigerian states.

    PubMed

    Oladepo, O; Brieger, W; Adeoye, B; Lawal, B; Peters, D H

    2011-12-01

    This paper assesses Patent Medicine Vendors' (PMVs) practices, awareness of new Nigerian Artemisinin Combination Therapy (ACT) policy, the anti-malarial drugs in stock and how the PMVs identify fake drugs. PMVs and medicine shops were selected through a multi-stage random sampling process, beginning with the purposive selection of three states that reflect major geographic and ethnolinguistic areas of Nigeria: Oyo (Southwest-Yoruba), Kaduna (Northcentral-Hausa), and Enugu (Southeast-Igbo). Local Government Areas (LGAs) in selected states were stratified into urban and rural strata, with two LGAs randomly sampled from each stratum in each state, and one ward (urban LGAs) or community (rural LGAs) randomly sampled from a list in each LGA. A complete listing of PMVs and drug shops was constructed at each site, yielding 111 PMVs and 106 medicine shops. Out of this number, a total of 110 PMVs consented to be interviewed. Some PMVs (43.1%) were aware of the 2005 government policy that changed the recommended first-line treatment for malaria from chloroquine (CQ) to ACT, but significant differences were found between states (p < 0.001). PMV shops stocked many brands of anti-malarial drugs (average 5.5 brands), with ACTs stocked in only 8.5% of the stores at a mean price of N504 ($4) per treatment, compared to sulfadoxine-pyrimethamine (92% of shops, mean price of N90 ($0.7) and even monotherapy artesunates (32% of shops, mean price of N39 ($0.3). The PMVs identify a drug not bearing the National Agency for Food & Drug Administration and Control (NAFDAC) identification number as being fake or counterfeit. PMVs need to be a part of the strategy to change treatment to ACTs if there are to be meaningful changes in the anti-malarial drugs that Nigerians receive.

  10. 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

  11. Self-reported data: a major tool to assess compliance with anti-malarial combination therapy among children in Senegal

    PubMed Central

    2009-01-01

    Background Although there are many methods available for measuring compliance, there is no formal gold standard. Different techniques used to measure compliance were compared among children treated by the anti-malarial amodiaquine/sulphadoxine-pyrimethamine (AQ/SP) combination therapy, in use in Senegal between 2004 and 2006. Methods The study was carried out in 2004, in five health centres located in the Thies region (Senegal). Children who had AQ/SP prescribed for three and one day respectively at the health centre were recruited. The day following the theoretical last intake of AQ, venous blood, and urine samples were collected for anti-malarial drugs dosage. Caregivers and children above five years were interviewed concerning children's drug intake. Results Among the children, 64.7% adhered to 80% of the prescribed dose and only 37.7% were strict full adherent to the prescription. There was 72.7% agreement between self-reported data and blood drug dosage for amodiaquine treatment. Concerning SP, results found that blood dosages were 91.4% concordant with urine tests and 90% with self-reported data based on questionnaires. Conclusion Self-reported data could provide useful quantitative information on drug intake and administration. Under strict methodological conditions this method, easy to implement, can be used to describe patients' behaviors and their use of new anti-malarial treatment. Self-reported data is a major tool for assessing compliance in resource poor countries. Blood and urine drug dosages provide qualitative results that confirm any drug intake. Urine assays for SP could be useful to obtain public health data, for example on chemoprophylaxis among pregnant women. PMID:19922609

  12. Optimizing the programmatic deployment of the anti-malarials artemether-lumefantrine and dihydroartemisinin-piperaquine using pharmacological modelling

    PubMed Central

    2014-01-01

    Background Successful programmatic use of anti-malarials faces challenges that are not covered by standard drug development processes. The development of appropriate pragmatic dosing regimens for low-resource settings or community-based use is not formally regulated, even though these may alter factors which can substantially affect individual patient and population level outcome, such as drug exposure, patient adherence and the spread of drug resistance and can affect a drug’s reputation and its eventual therapeutic lifespan. Methods An in silico pharmacological model of anti-malarial drug treatment with the pharmacokinetic/pharmacodynamic profiles of artemether-lumefantrine (AM-LF, Coartem®) and dihydroartemisinin-piperaquine (DHA-PPQ, Eurartesim®) was constructed to assess the potential impact of programmatic factors, including regionally optimized, age-based dosing regimens, poor patient adherence, food effects and drug resistance on treatment outcome at population level, and compared both drugs’ susceptibility to these factors. Results Compared with DHA-PPQ, therapeutic effectiveness of AM-LF seems more robust to factors affecting drug exposure, such as age- instead of weight-based dosing or poor adherence. The model highlights the sub-optimally low ratio of DHA:PPQ which, in combination with the narrow therapeutic dose range of PPQ compared to DHA that drives the weight or age cut-offs, leaves DHA at a high risk of under-dosing. Conclusion Pharmacological modelling of real-life scenarios can provide valuable supportive data and highlight modifiable determinants of therapeutic effectiveness that can help optimize the deployment of anti-malarials in control programmes. PMID:24708571

  13. Anti-malarial activity and toxicity assessment of Himatanthus articulatus, a plant used to treat malaria in the Brazilian Amazon.

    PubMed

    Vale, Valdicley V; Vilhena, Thyago C; Trindade, Rafaela C Santos; Ferreira, Márlia Regina C; Percário, Sandro; Soares, Luciana F; Pereira, Washington Luiz A; Brandão, Geraldo C; Oliveira, Alaíde B; Dolabela, Maria F; De Vasconcelos, Flávio

    2015-03-27

    Plasmodium falciparum has become resistant to some of the available drugs. Several plant species are used for the treatment of malaria, such as Himatanthus articulatus in parts of Brazil. The present paper reports the phyto-chemistry, the anti-plasmodial and anti-malarial activity, as well as the toxicity of H. articulatus. Ethanol and dichloromethane extracts were obtained from the powder of stem barks of H. articulatus and later fractionated and analysed. The anti-plasmodial activity was assessed against a chloroquine resistant strain P. falciparum (W2) in vitro, whilst in vivo anti-malarial activity against Plasmodium berghei (ANKA strain) was tested in mice, evaluating the role of oxidative stress (total antioxidant capacity--TEAC; lipid peroxidation--TBARS, and nitrites and nitrates--NN). In addition, cytotoxicity was evaluated using the HepG2 A16 cell-line. The acute oral and sub-chronic toxicity of the ethanol extract were evaluated in both male and female mice. Plumieride was isolated from the ethyl acetate fraction of ethanol extract, Only the dichloromethane extract was active against clone W2. Nevertheless, both extracts reduced parasitaemia in P. berghei-infected mice. Besides, a significant reduction in pulmonary and cerebral levels of NN (nitrites and nitrates) was found, as well as in pulmonary TBARS, indicating a reduced oxidative damage to these organs. The ethanol extract showed low cytotoxicity to HepG2 A16 cells in the concentrations used. No significant changes were observed in the in vivo toxicity studies. The ethanol extract of H. articulatus proved to be promising as anti-malarial medicine and showed low toxicity.

  14. 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

  15. Development and optimization of a novel 384-well anti-malarial imaging assay validated for high-throughput screening.

    PubMed

    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.

  16. A retrospective analysis of the change in anti-malarial treatment policy: Peru

    PubMed Central

    Williams, Holly Ann; Vincent-Mark, Arlene; Herrera, Yenni; Chang, O Jaime

    2009-01-01

    Background National malaria control programmes must deal with the complex process of changing national malaria treatment guidelines, often without guidance on the process of change. Selecting a replacement drug is only one issue in this process. There is a paucity of literature describing successful malaria treatment policy changes to help guide control programs through this process. Objectives To understand the wider context in which national malaria treatment guidelines were formulated in a specific country (Peru). Methods Using qualitative methods (individual and focus group interviews, stakeholder analysis and a review of documents), a retrospective analysis of the process of change in Peru's anti-malarial treatment policy from the early 1990's to 2003 was completed. Results The decision to change Peru's policies resulted from increasing levels of anti-malarial drug resistance, as well as complaints from providers that the drugs were no longer working. The context of the change occurred in a time in which Peru was changing national governments, which created extreme challenges in moving the change process forward. Peru utilized a number of key strategies successfully to ensure that policy change would occur. This included a) having the process directed by a group who shared a common interest in malaria and who had long-established social and professional networks among themselves, b) engaging in collaborative teamwork among nationals and between nationals and international collaborators, c) respect for and inclusion of district-level staff in all phases of the process, d) reliance on high levels of technical and scientific knowledge, e) use of standardized protocols to collect data, and f) transparency. Conclusion Although not perfectly or fully implemented by 2003, the change in malaria treatment policy in Peru occurred very quickly, as compared to other countries. They identified a problem, collected the data necessary to justify the change, utilized

  17. The potential of anti-malarial compounds derived from African medicinal plants, part II: a pharmacological evaluation of non-alkaloids and non-terpenoids

    PubMed Central

    2014-01-01

    Malaria is currently a public health concern in many countries in the world due to various factors which are not yet under check. Drug discovery projects targeting malaria often resort to natural sources in the search for lead compounds. A survey of the literature has led to a summary of the major findings regarding plant-derived compounds from African flora, which have shown anti-malarial/antiplasmodial activities, tested by in vitro and in vivo assays. Considerations have been given to compounds with activities ranging from “very active” to “weakly active”, leading to >500 chemical structures, mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylenes, xanthones, quinones, steroids and lignans. However, only the compounds that showed anti-malarial activity, from “very active” to “moderately active”, are discussed in this review. PMID:24602358

  18. In silico prediction of anti-malarial hit molecules based on machine learning methods.

    PubMed

    Kumari, Madhulata; Chandra, Subhash

    2015-01-01

    Machine learning techniques have been widely used in drug discovery and development in the areas of cheminformatics. Aspartyl aminopeptidase (M18AAP) of Plasmodium falciparum is crucial for survival of malaria parasite. We have created predictive models using weka and evaluated their performance based on various statistical parameters. Random Forest based model was found to be the most specificity (97.94%), with best accuracy (97.3%), MCC (0.306) as well as ROC (86.1%). The accuracy and MCC of these models indicated that they could be used to classify huge dataset of unknown compounds to predict their antimalarial compounds to develop effective drugs. Further, we deployed best predictive model on NCI diversity set IV. As result we found 59 bioactive anti-malarial molecules inhibiting M18AAP. Further, we obtained 18 non-toxic hit molecules out of 59 bioactive compounds. We suggest that such machine learning approaches could be applied to reduce the cost and length of time of drug discovery.

  19. Anti-malarial activity of 6-(8'Z-pentadecenyl)-salicylic acid from Viola websteri in mice.

    PubMed

    Chung, Ill-Min; Seo, Su-Hyun; Kang, Eun-Young; Park, Won-Hwan; Moon, Hyung-In

    2009-07-07

    Petroleum ether extracts of Viola websteri Hemsl (Violaceae) were reported to have anti-plasmodial activity against Plasmodium falciparum in vitro, with this activity being largely attributable to 6-(8'Z-pentadecenyl)-salicylic acid (6-SA). The schizontocidal activity of 6-SA on early Plasmodium berghei infections was evaluated in a four-day test. The possible 'repository' activity of 6-SA was assessed using the method described by Peters. The median lethal dose (LD50) of 6-SA, when given intraperitoneally, was also determined using uninfected ICR mice and the method of Lorke. In the present study, 6-SA was found to have anti-malarial activity in vivo, when tested against P. berghei in mice. 6-SA at 5, 10 and 25 mg/kg x day exhibited a significant blood schizontocidal activity in four-day early infections, repository evaluations and established infections with a significant mean survival time comparable to that of the standard drug, chloroquine (5 mg/kg.day). 6-SA possesses a moderate anti-malarial activity that could be exploited for malaria therapy.

  20. The potential of anti-malarial compounds derived from African medicinal plants, part I: a pharmacological evaluation of alkaloids and terpenoids.

    PubMed

    Amoa Onguéné, Pascal; Ntie-Kang, Fidele; Lifongo, Lydia Likowo; Ndom, Jean Claude; Sippl, Wolfgang; Mbaze, Luc Meva'a

    2013-12-13

    Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from "very active" to "weakly active". However, only the compounds which showed anti-malarial activities from "very active" to "moderately active" are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria.

  1. The potential of anti-malarial compounds derived from African medicinal plants, part I: a pharmacological evaluation of alkaloids and terpenoids

    PubMed Central

    2013-01-01

    Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from “very active” to “weakly active”. However, only the compounds which showed anti-malarial activities from “very active” to “moderately active” are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria. PMID:24330395

  2. In vitro interaction of artemisinin derivatives or the fully synthetic peroxidic anti-malarial OZ277 with thapsigargin in Plasmodium falciparum strains

    PubMed Central

    2013-01-01

    Background Semi-synthetic artemisinin derivatives are powerful peroxidic drugs in artemisinin-based combination therapy (ACT) recommended as first-line treatment of Plasmodium falciparum malaria in disease-endemic countries. Studies by Eckstein-Ludwig and co-workers showed both thapsigargin and artemisinin specifically inhibit the sarcoplasmic reticulum Ca2+−ATPase of Plasmodium falciparum (PfATP6). In the present study the type of interaction between thapsigargin and artemisinin derivatives as well as the ozonide OZ277 (RBx11160 or arterolane) was evaluated in parasite cultures. The latter compound is an adamantane-based peroxide and the first fully synthetic clinical candidate recently registered in India by Ranbaxy Laboratories Ltd. for anti-malarial combination therapy. Methods Drug interaction studies were performed using a previously described fixed ratio method and anti-malarial activity measured using the [3H] hypoxanthine incorporation assay. Results The sum 50% and 90% fractional inhibitory concentration (∑FIC50, 90) of the interaction of thapsigargin with OZ277, artemether or artesunate, against NF54 and K1 strains of P. falciparum ranged from 0.9 to 1.4. Conclusion The interaction of thapsigargin with OZ277, artesunate or artemether was additive, data consistent with previous observations indicating that activity of anti-malarial peroxides does not derive from reversible interactions with parasite targets. PMID:23368889

  3. Anti-malarial activity of indole alkaloids isolated from Aspidosperma olivaceum

    PubMed Central

    2014-01-01

    Background Several species of Aspidosperma (Apocynaceae) are used as treatments for human diseases in the tropics. Aspidosperma olivaceum, which is used to treat fevers in some regions of Brazil, contains the monoterpenoid indole alkaloids (MIAs) aspidoscarpine, uleine, apparicine, and N-methyl-tetrahydrolivacine. Using bio-guided fractionation and cytotoxicity testing in a human hepatoma cell line, several plant fractions and compounds purified from the bark and leaves of the plant were characterized for specific therapeutic activity (and selectivity index, SI) in vitro against the blood forms of Plasmodium falciparum. Methods The activity of A. olivaceum extracts, fractions, and isolated compounds was evaluated against chloroquine (CQ)-resistant P. falciparum blood parasites by in vitro testing with radiolabelled [3H]-hypoxanthine and a monoclonal anti-histidine-rich protein (HRPII) antibody. The cytotoxicity of these fractions and compounds was evaluated in a human hepatoma cell line using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, and the SI was calculated as the ratio between the toxicity and activity. Two leaf fractions were tested in mice with Plasmodium berghei. Results All six fractions from the bark and leaf extracts were active in vitro at low doses (IC50 < 5.0 μg/mL) using the anti-HRPII test, and only two (the neutral and basic bark fractions) were toxic to a human cell line (HepG2). The most promising fractions were the crude leaf extract and its basic residue, which had SIs above 50. Among the four pure compounds evaluated, aspidoscarpine in the bark and leaf extracts showed the highest SI at 56; this compound, therefore, represents a possible anti-malarial drug that requires further study. The acidic leaf fraction administered by gavage to mice with blood-induced malaria was also active. Conclusion Using a bio-monitoring approach, it was possible to attribute the anti-P. falciparum activity of A. olivaceum to

  4. An ethnobotanical study of anti-malarial plants among indigenous people on the upper Negro River in the Brazilian Amazon.

    PubMed

    Frausin, Gina; Hidalgo, Ari de Freitas; Lima, Renata Braga Souza; Kinupp, Valdely Ferreira; Ming, Lin Chau; Pohlit, Adrian Martin; Milliken, William

    2015-11-04

    material available, the patient's age (children and adults) and the local expert. The treatment time varies from a single dose to up to several weeks. Most anti-malarial plants are domesticated or grow spontaneously. They are grown in home gardens, open areas near the communities, clearings and secondary forests, and wild species grow in areas of seasonally flooded wetlands and terra firme ('solid ground') forest, in some cases in locations that are hard to access. Traditional knowledge of plants was found to be falling into disuse presumably as a consequence of the local official health services that treat malaria in the communities using commercial drugs. Despite this, some species are used in the prevention of this disease and also in the recovery after using conventional anti-malarial drugs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. A population genetic model for the initial spread of partially resistant malaria parasites under anti-malarial combination therapy and weak intrahost competition.

    PubMed

    Kim, Yuseob; Escalante, Ananias A; Schneider, Kristan A

    2014-01-01

    To develop public-health policies that extend the lifespan of affordable anti-malarial drugs as effective treatment options, it is necessary to understand the evolutionary processes leading to the origin and spread of mutations conferring drug resistance in malarial parasites. We built a population-genetic model for the emergence of resistance under combination drug therapy. Reproductive cycles of parasites are specified by their absolute fitness determined by clinical parameters, thus coupling the evolutionary-genetic with population-dynamic processes. Initial mutations confer only partial drug-resistance. Therefore, mutant parasites rarely survive combination therapy and within-host competition is very weak among parasites. The model focuses on the early phase of such unsuccessful recurrent mutations. This ends in the rare event of mutants enriching in an infected individual from which the successful spread of resistance over the entire population is initiated. By computer simulations, the waiting time until the establishment of resistant parasites is analysed. Resistance spreads quickly following the first appearance of a host infected predominantly by mutant parasites. This occurs either through a rare transmission of a resistant parasite to an uninfected host or through a rare failure of drugs in removing "transient" mutant alleles. The emergence of resistance is delayed with lower mutation rate, earlier treatment, higher metabolic cost of resistance, longer duration of high drug dose, and higher drug efficacy causing a stronger reduction in the sensitive and resistant parasites' fitnesses. Overall, contrary to other studies' proposition, the current model based on absolute fitness suggests that aggressive drug treatment delays the emergence of drug resistance.

  6. Accessibility, availability and affordability of anti-malarials in a rural district in Kenya after implementation of a national subsidy scheme.

    PubMed

    Smith, Nathan; Obala, Andrew; Simiyu, Chrispinus; Menya, Diana; Khwa-Otsyula, Barasa; O'Meara, Wendy Prudhomme

    2011-10-26

    Poor access to prompt and effective treatment for malaria contributes to high mortality and severe morbidity. In Kenya, it is estimated that only 12% of children receive anti-malarials for their fever within 24 hours. The first point of care for many fevers is a local medicine retailer, such as a pharmacy or chemist. The role of the medicine retailer as an important distribution point for malaria medicines has been recognized and several different strategies have been used to improve the services that these retailers provide. Despite these efforts, many mothers still purchase ineffective drugs because they are less expensive than effective artemisinin combination therapy (ACT). One strategy that is being piloted in several countries is an international subsidy targeted at anti-malarials supplied through the retail sector. The goal of this strategy is to make ACT as affordable as ineffective alternatives. The programme, called the Affordable Medicines Facility - malaria was rolled out in Kenya in August 2010. In December 2010, the affordability and accessibility of malaria medicines in a rural district in Kenya were evaluated using a complete census of all public and private facilities, chemists, pharmacists, and other malaria medicine retailers within the Webuye Demographic Surveillance Area. Availability, types, and prices of anti-malarials were assessed. There are 13 public or mission facilities and 97 medicine retailers (registered and unregistered). The average distance from a home to the nearest public health facility is 2 km, but the average distance to the nearest medicine retailer is half that. Quinine is the most frequently stocked anti-malarial (61% of retailers). More medicine retailers stocked sulphadoxine-pyramethamine (SP; 57%) than ACT (44%). Eleven percent of retailers stocked AMFm subsidized artemether-lumefantrine (AL). No retailers had chloroquine in stock and only five were selling artemisinin monotherapy. The mean price of any brand of AL, the

  7. Mass anti-malarial administration in western Cambodia: a qualitative study of factors affecting coverage.

    PubMed

    Pell, Christopher; Tripura, Rupam; Nguon, Chea; Cheah, Phaikyeong; Davoeung, Chan; Heng, Chhouen; Dara, Lim; Sareth, Ma; Dondorp, Arjen; von Seidlein, Lorenz; Peto, Thomas J

    2017-05-19

    Mass anti-malarial administration has been proposed as a key component of the Plasmodium falciparum malaria elimination strategy in the Greater Mekong sub-Region. Its effectiveness depends on high levels of coverage in the target population. This article explores the factors that influenced mass anti-malarial administration coverage within a clinical trial in Battambang Province, western Cambodia. Qualitative data were collected through semi-structured interviews and focus group discussions with villagers, in-depth interviews with study staff, trial drop-outs and refusers, and observations in the communities. Interviews were audio-recorded, transcribed and translated from Khmer to English for qualitative content analysis using QSR NVivo. Malaria was an important health concern and villagers reported a demand for malaria treatment. This was in spite of a fall in incidence over the previous decade and a lack of familiarity with asymptomatic malaria. Participants generally understood the overall study aim and were familiar with study activities. Comprehension of the study rationale was however limited. After the first mass anti-malarial administration, seasonal health complaints that participants attributed to the anti-malarial as "side effects" contributed to a decrease of coverage in round two. Staff therefore adapted the community engagement approach, bringing to prominence local leaders in village meetings. This contributed to a subsequent increase in coverage. Future mass anti-malarial administration must consider seasonal disease patterns and the importance of local leaders taking prominent roles in community engagement. Further research is needed to investigate coverage in scenarios that more closely resemble implementation i.e. without participation incentives, blood sampling and free healthcare.

  8. Thiamin supplementation does not reduce the frequency of adverse events after anti-malarial therapy among patients with falciparum malaria in southern Laos

    PubMed Central

    2014-01-01

    Background In a recent study one third of Lao patients presenting with uncomplicated Plasmodium falciparum malaria had biochemical evidence of thiamin deficiency, which was associated with a higher incidence of adverse events. Thiamin supplementation might, therefore, reduce adverse events in this population. Methods An exploratory, double-blind, parallel group, placebo-controlled, superiority trial of thiamin supplementation in patients of all ages with uncomplicated and severe falciparum malaria was conducted in Xepon District, Savannakhet Province, southern Laos. Patients were randomly assigned to either oral thiamin 10 mg/day for 7 days immediately after standard anti-malarial treatment then 5 mg daily until day 42, or identical oral placebo. Results After interim analyses when 630 patients (314 in thiamin and 316 in placebo groups) had been recruited, the trial was discontinued on the grounds of futility. On admission biochemical thiamin deficiency (alpha ≥ 25%) was present in 27% of patients and 9% had severe deficiency (alpha > 31%). After 42 days of treatment, the frequency of thiamin deficiency was lower in the thiamin (2%, 1% severe) compared to the placebo (11%, 3% severe) groups (p < 0.001 and p = 0.05), respectively. Except for diarrhoea, 7% in the placebo compared to 3% in the thiamin group (p = 0.04), and dizziness on day 1 (33% vs 25%, p = 0.045), all adverse events were not significantly different between the groups (p > 0.05). Clinical, haematological, and parasitological responses to treatment did not differ significantly between the two groups. Conclusion Thiamin supplementation reduced biochemical thiamin deficiency among Lao malaria patients following anti-malarial drug treatment, but it did not reduce the frequency of adverse events after anti-malarial therapy or have any detected clinical or parasitological impact. Trial registration ISRCTN 85411059 PMID:25027701

  9. Novel anti-malarial combinations and their toxicity.

    PubMed

    Angus, Brian

    2014-05-01

    Artemisinin combination therapy for the treatment of uncomplicated malaria includes artemether plus lumefantrine, artesunate plus amodiaquine, artesunate plus mefloquine, artesunate plus sulfadoxine-pyrimethamine and dihydroartemisinin plus piperaquine. These drugs are safe and efficacious at present. The emergence of artemisinin resistant parasites in SE Asia means that there is a need to optimise drug dosing and investigate novel therapies to maintain the impressive reduction in malaria mortality which has been seen in the past decade.

  10. Quality of anti-malarials collected in the private and informal sectors in Guyana and Suriname

    PubMed Central

    2012-01-01

    Background Despite a significant reduction in the number of malaria cases in Guyana and Suriname, this disease remains a major problem in the interior of both countries, especially in areas with gold mining and logging operations, where malaria is endemic. National malaria control programmes in these countries provide treatment to patients with medicines that are procured and distributed through regulated processes in the public sector. However, availability to medicines in licensed facilities (private sector) and unlicensed facilities (informal sector) is common, posing the risk of access to and use of non-recommended treatments and/or poor quality products. Methods To assess the quality of circulating anti-malarial medicines, samples were purchased in the private and informal sectors of Guyana and Suriname in 2009. The sampling sites were selected based on epidemiological data and/or distance from health facilities. Samples were analysed for identity, content, dissolution or disintegration, impurities, and uniformity of dosage units or weight variation according to manufacturer, pharmacopeial, or other validated method. Results Quality issues were observed in 45 of 77 (58%) anti-malarial medicines sampled in Guyana of which 30 failed visual & physical inspection and 18 failed quality control tests. The proportion of monotherapy and ACT medicines failing quality control tests was 43% (13/30) and 11% (5/47) respectively. A higher proportion of medicines sampled from the private sector 34% (11/32) failed quality control tests versus 16% (7/45) in the informal sector. In Suriname, 58 medicines were sampled, of which 50 (86%) were Artecom®, the fixed-dose combination of piperaquine-dihydroartemisinin-trimethoprim co-blistered with a primaquine phosphate tablet. All Artecom samples were found to lack a label claim for primaquine, thus failing visual and physical inspection. Conclusions The findings of the studies in both countries point to significant problems with

  11. Genetic determinants of anti-malarial acquired immunity in a large multi-centre study.

    PubMed

    Shelton, Jennifer M G; Corran, Patrick; Risley, Paul; Silva, Nilupa; Hubbart, Christina; Jeffreys, Anna; Rowlands, Kate; Craik, Rachel; Cornelius, Victoria; Hensmann, Meike; Molloy, Sile; Sepulveda, Nuno; Clark, Taane G; Band, Gavin; Clarke, Geraldine M; Spencer, Christopher C A; Kerasidou, Angeliki; Campino, Susana; Auburn, Sarah; Tall, Adama; Ly, Alioune Badara; Mercereau-Puijalon, Odile; Sakuntabhai, Anavaj; Djimdé, Abdoulaye; Maiga, Boubacar; Touré, Ousmane; Doumbo, Ogobara K; Dolo, Amagana; Troye-Blomberg, Marita; Mangano, Valentina D; Verra, Frederica; Modiano, David; Bougouma, Edith; Sirima, Sodiomon B; Ibrahim, Muntaser; Hussain, Ayman; Eid, Nahid; Elzein, Abier; Mohammed, Hiba; Elhassan, Ahmed; Elhassan, Ibrahim; Williams, Thomas N; Ndila, Carolyne; Macharia, Alexander; Marsh, Kevin; Manjurano, Alphaxard; Reyburn, Hugh; Lemnge, Martha; Ishengoma, Deus; Carter, Richard; Karunaweera, Nadira; Fernando, Deepika; Dewasurendra, Rajika; Drakeley, Christopher J; Riley, Eleanor M; Kwiatkowski, Dominic P; Rockett, Kirk A

    2015-08-28

    Many studies report associations between human genetic factors and immunity to malaria but few have been reliably replicated. These studies are usually country-specific, use small sample sizes and are not directly comparable due to differences in methodologies. This study brings together samples and data collected from multiple sites across Africa and Asia to use standardized methods to look for consistent genetic effects on anti-malarial antibody levels. Sera, DNA samples and clinical data were collected from 13,299 individuals from ten sites in Senegal, Mali, Burkina Faso, Sudan, Kenya, Tanzania, and Sri Lanka using standardized methods. DNA was extracted and typed for 202 Single Nucleotide Polymorphisms with known associations to malaria or antibody production, and antibody levels to four clinical grade malarial antigens [AMA1, MSP1, MSP2, and (NANP)4] plus total IgE were measured by ELISA techniques. Regression models were used to investigate the associations of clinical and genetic factors with antibody levels. Malaria infection increased levels of antibodies to malaria antigens and, as expected, stable predictors of anti-malarial antibody levels included age, seasonality, location, and ethnicity. Correlations between antibodies to blood-stage antigens AMA1, MSP1 and MSP2 were higher between themselves than with antibodies to the (NANP)4 epitope of the pre-erythrocytic circumsporozoite protein, while there was little or no correlation with total IgE levels. Individuals with sickle cell trait had significantly lower antibody levels to all blood-stage antigens, and recessive homozygotes for CD36 (rs321198) had significantly lower anti-malarial antibody levels to MSP2. Although the most significant finding with a consistent effect across sites was for sickle cell trait, its effect is likely to be via reducing a microscopically positive parasitaemia rather than directly on antibody levels. However, this study does demonstrate a framework for the feasibility of

  12. Several human cyclin-dependent kinase inhibitors, structurally related to roscovitine, are new anti-malarial agents.

    PubMed

    Houzé, Sandrine; Hoang, Nha-Thu; Lozach, Olivier; Le Bras, Jacques; Meijer, Laurent; Galons, Hervé; Demange, Luc

    2014-09-23

    In Africa, malaria kills one child each minute. It is also responsible for about one million deaths worldwide each year. Plasmodium falciparum, is the protozoan responsible for the most lethal form of the disease, with resistance developing against the available anti-malarial drugs. Among newly proposed anti-malaria targets, are the P. falciparum cyclin-dependent kinases (PfCDKs). There are involved in different stages of the protozoan growth and development but share high sequence homology with human cyclin-dependent kinases (CDKs). We previously reported the synthesis of CDKs inhibitors that are structurally-related to (R)-roscovitine, a 2,6,9-trisubstituted purine, and they showed activity against neuronal diseases and cancers. In this report, we describe the synthesis and the characterization of new CDK inhibitors, active in reducing the in vitro growth of P. falciparum (3D7 and 7G8 strains). Six compounds are more potent inhibitors than roscovitine, and three exhibited IC50 values close to 1 µM for both 3D7 and 7G8 strains. Although, such molecules do inhibit P. falciparum growth, they require further studies to improve their selectivity for PfCDKs.

  13. A Water-Soluble Polysaccharide from the Fruit Bodies of Bulgaria inquinans (Fries) and Its Anti-Malarial Activity

    PubMed Central

    Bi, Hongtao; Han, Han; Li, Zonghong; Ni, Weihua; Chen, Yan; Zhu, Jingjing; Gao, Tingting; Hao, Miao; Zhou, Yifa

    2011-01-01

    A water-soluble polysaccharide (BIWS-4b) was purified from the fruit bodies of Bulgaria inquinans (Fries). It is composed of mannose (27.2%), glucose (15.5%) and galactose (57.3%). Its molecular weight was estimated to be 7.4 kDa (polydispersity index, Mw/Mn: 1.35). Structural analyses indicated that BIWS-4b mainly contains (1 → 6)-linked, (1 → 5)-linked and (1 → 5,6)-linked β-Galf units; (1 → 4)-linked and non-reducing terminal β-Glcp units; and (1 → 2)-linked, (1 → 6)-linked, (1 → 2,6)-linked and non-reducing terminal α-Manp units. When examined by the 4-day method and in a prophylactic assay in mice, BIWS-4b exhibited markedly suppressive activity against malaria while enhancing the activity of artesunate. Immunological tests indicated that BIWS-4b significantly enhanced macrophage phagocytosis and splenic lymphocyte proliferation in malaria-bearing mice and normal mice. The anti-malarial activity of BIWS-4b might be intermediated by enhancing immune competence and restoring artesunate-suppressed immune function. Thus, BIWS-4b is a potential adjuvant of anti-malaria drugs. PMID:21785644

  14. Structural characterisation of sporozoite components for a multistage, multi-epitope, anti-malarial vaccine.

    PubMed

    Patarroyo, Manuel E; Cifuentes, Gladys; Rodríguez, Raúl

    2008-01-01

    A totally effective anti-malarial vaccine must contain epitopes derived from multiple proteins found in different stages of the particular parasite involved in invasion. It must therefore include sporozoite molecules able to induce protective immunity thereby blocking the parasite's access to hepatic cells; thrombospondin-related anonymous protein (TRAP) is one of them. Conserved high activity binding peptides (HABPs) attaching themselves to hepatic cells were used in immunisation studies with the highly malaria-susceptible Aotus monkey. However, they had to be modified to render them immunogenic. The changes induced in lead peptide 3D structure were analysed by correlating such substitutions with the induction of high anti-sporozoite antibody levels in the experimental monkey model. The modification induced structural changes in most modified HABPs, changing them from random-coil or distorted type III beta-turn structures to classical type III or III' beta-turn, thereby allowing a better fit into the MHC-II-peptide-TCR complex since they bound with high affinity to purified HLA-DRbeta1* molecules. These are the first (TRAP) conserved HABPs corresponding to functionally active amino acid sequences in sporozoite invasion and mobility which, when modified, were able to induce very high anti-sporozoite antibody responses, leading to suggesting them as components in the first line of defence of a fully-effective, subunit-based, multi-epitope, multi-stage, synthetic anti-malarial vaccine.

  15. In silico analysis reveals the anti-malarial potential of quinolinyl chalcone derivatives.

    PubMed

    Thillainayagam, Mahalakshmi; Pandian, Lavanya; Murugan, Kumar Kalavathy; Vijayaparthasarathi, Vijayakumar; Sundaramoorthy, Sarveswari; Anbarasu, Anand; Ramaiah, Sudha

    2015-01-01

    In this study, the correlation between chemical structures and various parameters such as steric effects and electrostatic interactions to the inhibitory activities of quinolinyl chalcone derivatives is derived to identify the key structural elements required in the rational design of potent and novel anti-malarial compounds. The molecular docking simulations and Comparative Molecular Field Analysis (CoMFA) are carried out on 38 chalcones derivatives using Plasmodium falciparum lactate dehydrogenase (PfLDH) as potential target. Surflex-dock is used to determine the probable binding conformations of all the compounds at the active site of pfLDH and to identify the hydrogen bonding interactions which could be used to alter the inhibitory activities. The CoMFA model has provided statistically significant results with the cross-validated correlation coefficient (q(2)) of .850 and the non-cross-validated correlation coefficient (r(2)) of .912. Standard error of estimation (SEE) is .280 and the optimum number of component is five. The predictive ability of the resultant model is evaluated using a test set comprising of 13 molecules and the predicted r(2) value is .885. The results provide valuable insight for optimization of quinolinyl chalcone derivatives for better anti-malarial therapy.

  16. Self-medication with anti-malarials is a common practice in rural communities of Kilosa district in Tanzania despite the reported decline of malaria

    PubMed Central

    2014-01-01

    Background Self-medication has been widely practiced worldwide particularly in developing countries including Tanzania. In sub-Saharan Africa high incidences of malaria have contributed to self-medication with anti-malarial drugs. In recent years, there has been a gain in malaria control, which has led to decreased malaria transmission, morbidity and mortality. Therefore, understanding the patterns of self-medication during this period when most instances of fever are presumed to be due to non-malaria febrile illnesses is important. In this study, self-medication practice was assessed among community members and information on the habit of self-medication was gathered from health workers. Methods Twelve focus group discussions (FGD) with members of communities and 14 in-depth interviews (IDI) with health workers were conducted in Kilosa district, Tanzania. The transcripts were coded into different categories by MaxQDA software and then analysed through thematic content analysis. Results The study revealed that self-medication was a common practice among FGD participants. Anti-malarial drugs including sulphadoxine-pyrimethamine and quinine were frequently used by the participants for treatment of fever. Study participants reported that they visited health facilities following failure of self-medication or if there was no significant improvement after self-medication. The common reported reasons for self-medication were shortages of drugs at health facilities, long waiting time at health facilities, long distance to health facilities, inability to pay for health care charges and the freedom to choose the preferred drugs. Conclusion This study demonstrated that self-medication practice is common among rural communities in the study area. The need for community awareness is emphasized for correct and comprehensive information about drawbacks associated with self-medication practices. Deliberate efforts by the government and other stakeholders to improve health care

  17. Self-medication with anti-malarials is a common practice in rural communities of Kilosa district in Tanzania despite the reported decline of malaria.

    PubMed

    Chipwaza, Beatrice; Mugasa, Joseph P; Mayumana, Iddy; Amuri, Mbaraka; Makungu, Christina; Gwakisa, Paul S

    2014-07-03

    Self-medication has been widely practiced worldwide particularly in developing countries including Tanzania. In sub-Saharan Africa high incidences of malaria have contributed to self-medication with anti-malarial drugs. In recent years, there has been a gain in malaria control, which has led to decreased malaria transmission, morbidity and mortality. Therefore, understanding the patterns of self-medication during this period when most instances of fever are presumed to be due to non-malaria febrile illnesses is important. In this study, self-medication practice was assessed among community members and information on the habit of self-medication was gathered from health workers. Twelve focus group discussions (FGD) with members of communities and 14 in-depth interviews (IDI) with health workers were conducted in Kilosa district, Tanzania. The transcripts were coded into different categories by MaxQDA software and then analysed through thematic content analysis. The study revealed that self-medication was a common practice among FGD participants. Anti-malarial drugs including sulphadoxine-pyrimethamine and quinine were frequently used by the participants for treatment of fever. Study participants reported that they visited health facilities following failure of self-medication or if there was no significant improvement after self-medication. The common reported reasons for self-medication were shortages of drugs at health facilities, long waiting time at health facilities, long distance to health facilities, inability to pay for health care charges and the freedom to choose the preferred drugs. This study demonstrated that self-medication practice is common among rural communities in the study area. The need for community awareness is emphasized for correct and comprehensive information about drawbacks associated with self-medication practices. Deliberate efforts by the government and other stakeholders to improve health care services, particularly at primary health

  18. Methods for implementing a medicine outlet survey: lessons from the anti-malarial market

    PubMed Central

    2013-01-01

    Background In recent years an increasing number of public investments and policy changes have been made to improve the availability, affordability and quality of medicines available to consumers in developing countries, including anti-malarials. It is important to monitor the extent to which these interventions are successful in achieving their aims using quantitative data on the supply side of the market. There are a number of challenges related to studying supply, including outlet sampling, gaining provider cooperation and collecting accurate data on medicines. This paper provides guidance on key steps to address these issues when conducting a medicine outlet survey in a developing country context. While the basic principles of good survey design and implementation are important for all surveys, there are a set of specific issues that should be considered when conducting a medicine outlet survey. Methods This paper draws on the authors’ experience of designing and implementing outlet surveys, including the lessons learnt from ACTwatch outlet surveys on anti-malarial retail supply, and other key studies in the field. Key lessons and points of debate are distilled around the following areas: selecting a sample of outlets; techniques for collecting and analysing data on medicine availability, price and sales volumes; and methods for ensuring high quality data in general. Results and conclusions The authors first consider the inclusion criteria for outlets, contrasting comprehensive versus more focused approaches. Methods for developing a reliable sampling frame of outlets are then presented, including use of existing lists, key informants and an outlet census. Specific issues in the collection of data on medicine prices and sales volumes are discussed; and approaches for generating comparable price and sales volume data across products using the adult equivalent treatment dose (AETD) are explored. The paper concludes with advice on practical considerations

  19. Culture-adapted Plasmodium falciparum isolates from UK travellers: in vitro drug sensitivity, clonality and drug resistance markers

    PubMed Central

    2013-01-01

    Background The screening of lead compounds against in vitro parasite cultures is an essential step in the development of novel anti-malarial drugs, but currently relies on laboratory parasite lines established in vitro during the last century. This study sought to establish in continuous culture a series of recent Plasmodium falciparum isolates to represent the current parasite populations in Africa, all of which are now exposed to artemisinin combination therapy. Methods Pre-treatment P. falciparum isolates were obtained in EDTA, and placed into continuous culture after sampling of DNA. One post-treatment blood sample was also collected for each donor to monitor parasite clonality during clearance in vivo. IC50 estimates were obtained for 11 anti-malarial compounds for each established parasite line, clonal multiplicity measured in vivo and in vitro, and polymorphic sites implicated in parasite sensitivity to drugs were investigated at the pfmdr1, pfcrt, pfdhfr, pfdhps and pfap2mu loci before and after treatment, and in the cultured lines. Results Plasmodium falciparum isolates from seven malaria patients with recent travel to three West African and two East African countries were successfully established in long-term culture. One of these, HL1211, was from a patient with recrudescent parasitaemia 14 days after a full course of artemether-lumefantrine. All established culture lines were shown to be polyclonal, reflecting the in vivo isolates from which they were derived, and at least two lines reliably produce gametocytes in vitro. Two lines displayed high chloroquine IC50 estimates, and carried the CVIET haplotype at codons 72–76, whereas the remaining five lines carried the CVMNK haplotype and were sensitive in vitro. All were sensitive to the endoperoxides dihydroartemisinin and OZ277, but IC50 estimates for lumefantrine varied, with the least sensitive parasites carrying pfmdr1 alleles encoding Asn at codon 86. Conclusions This study describes the

  20. Pharmacologic Inhibition of CXCL10 in Combination with Anti-malarial Therapy Eliminates Mortality Associated with Murine Model of Cerebral Malaria

    PubMed Central

    Wilson, Nana O.; Solomon, Wesley; Anderson, Leonard; Patrickson, John; Pitts, Sidney; Bond, Vincent; Liu, Mingli; Stiles, Jonathan K.

    2013-01-01

    Despite appropriate anti-malarial treatment, cerebral malaria (CM)-associated mortalities remain as high as 30%. Thus, adjunctive therapies are urgently needed to prevent or reduce such mortalities. Overproduction of CXCL10 in a subset of CM patients has been shown to be tightly associated with fatal human CM. Mice with deleted CXCL10 gene are partially protected against experimental cerebral malaria (ECM) mortality indicating the importance of CXCL10 in the pathogenesis of CM. However, the direct effect of increased CXCL10 production on brain cells is unknown. We assessed apoptotic effects of CXCL10 on human brain microvascular endothelial cells (HBVECs) and neuroglia cells in vitro. We tested the hypothesis that reducing overexpression of CXCL10 with a synthetic drug during CM pathogenesis will increase survival and reduce mortality. We utilized atorvastatin, a widely used synthetic blood cholesterol-lowering drug that specifically targets and reduces plasma CXCL10 levels in humans, to determine the effects of atorvastatin and artemether combination therapy on murine ECM outcome. We assessed effects of atorvastatin treatment on immune determinants of severity, survival, and parasitemia in ECM mice receiving a combination therapy from onset of ECM (day 6 through 9 post-infection) and compared results with controls. The results indicate that CXCL10 induces apoptosis in HBVECs and neuroglia cells in a dose-dependent manner suggesting that increased levels of CXCL10 in CM patients may play a role in vasculopathy, neuropathogenesis, and brain injury during CM pathogenesis. Treatment of ECM in mice with atorvastatin significantly reduced systemic and brain inflammation by reducing the levels of the anti-angiogenic and apoptotic factor (CXCL10) and increasing angiogenic factor (VEGF) production. Treatment with a combination of atorvastatin and artemether improved survival (100%) when compared with artemether monotherapy (70%), p<0.05. Thus, adjunctively reducing CXCL10

  1. Ethnobotanical study on some Malaysian anti-malarial plants: a community based survey.

    PubMed

    Al-Adhroey, Abdulelah H; Nor, Zurainee M; Al-Mekhlafi, Hesham M; Mahmud, Rohela

    2010-10-28

    Various plants species are used in the traditional medicine for the treatment of malaria. This is the first community based ethnobotanical study in Peninsular Malaysia. To investigate the plants traditionally used in the treatment of malaria in Malaysia. An ethnobotanical survey was carried out among 233 Aboriginal and rural households, and traditional healers in malaria endemic areas in Peninsular Malaysia. Data were collected using a pre-tested questionnaire. Nineteen species belonging to 17 families were identified. Twelve plant species have not previously been documented for the treatment of malaria in Malaysia. Findings of this study can be used as an ethnopharmacological basis for selecting plants for further anti-malarial phytochemical and pharmaceutical studies. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  2. Combating poor-quality anti-malarial medicines: a call to action.

    PubMed

    Bassat, Quique; Tanner, Marcel; Guerin, Philippe J; Stricker, Kirstin; Hamed, Kamal

    2016-06-01

    The circulation of poor-quality medicines continues to undermine the fight against many life-threatening diseases. Anti-malarial medicines appear to have been particularly compromised and present a major public health threat in malaria-endemic countries, negatively affecting individuals and their communities. Concerted collaborative efforts are required from global, regional and national organizations, involving the public and private sectors, to address the problem. While many initiatives are underway, a number of unmet needs deserve urgent and increased multisector attention. At the global level, there is a need for an international public health legal framework or treaty on poor-quality medicines, with statutes suitable for integration into national laws. In addition, increased international efforts are required to strengthen the governance of global supply chains and enhance cooperation between national medicine regulation authorities and law enforcement bodies. Increased investment is needed in innovative technologies that will enable healthcare teams to detect poor-quality medicines at all levels of the supply chain. At the regional level, a number of initiatives would be beneficial-key areas are standardization, simplification, and reciprocal recognition of registration processes and development of quality control capacity in regional centres of excellence that are better aligned with public health needs; improved surveillance methods and creation of a framework for compulsory and transparent reporting of poor-quality medicines; additional support for national medicine regulation authorities and other national partner authorities; and an increase in support for regional laboratories to boost their capabilities in detecting poor-quality medicines. It is vital that all stakeholders involved in efforts against poor-quality anti-malarial medicines extend and strengthen their actions in these critical areas and thus effectively support global health development

  3. Hypericum lanceolatum (Hypericaceae) as a potential source of new anti-malarial agents: a bioassay-guided fractionation of the stem bark

    PubMed Central

    2011-01-01

    Background Malaria is a major public health threat in Africa, and traditional medicine continues to play a key role in its control especially in rural areas. A bioassay-guided fractionation was carried out in order to evaluate the anti-malarial potential and the safety of the methanol extract of the Hypericum lanceolatum stem bark. Methods The anti-plasmodial activity was assayed by the lactate dehydrogenase method (pLDH) against the multidrug-resistant W2mef laboratory strain, and a field isolate (SHF4) of Plasmodium falciparum. Cytotoxicity tests were carried out using the LLC-MK2 monkey kidney epithelial cells. Results Five compounds were isolated from the most active and least cytotoxic ethylacetate sub-extract: betulinic acid (HLT1), 2,2',5,6'-tetrahydroxybenzophenone (HLT2), 5-hydroxy-3-methoxyxanthone (HLT3), 3-hydroxy-5-methoxyxanthone (HLT4) and HLT0 (yet to be identified). Three of the tested compounds presented significant anti-plasmodial activities (with 50% inhibitory concentration, IC50 < 5 μM), with 5-hydroxy-3-methoxyxanthone exerting the highest activity, followed by HLT0 and betulinic acid. All the compounds with significant anti-plasmodial activity were non-cytotoxic, except betulinic acid which showed a 50% cytotoxic concentration, CC50 of 25 μg/mL. Conclusions These findings justify the use of H. lanceolatum stem bark as anti-malarial by traditional healers of Western Cameroon, and could constitute a good basis for further studies towards development of new drug candidates or phytomedicines for malaria. PMID:21682873

  4. Chinese propriety medicines: an "alternative modernity?" The case of the anti-malarial substance artemisinin in East Africa.

    PubMed

    Hsu, Elisabeth

    2009-01-01

    This article discusses various modes of "modernizing" traditional Chinese medical drugs (zhongyao [image: see text]) and transforming them into so-called Chinese propriety medicines (zhongchengyao [image: see text]) that are flooding the current neoliberal wellness markets. This article argues that the chemical procedures used in the manufacture of Chinese propriety medicines are highly culture-specific and deserve being considered as instantiations of an "alternative modernity" (e.g., Knauft 2002), rather than of "Westernization." These Western-Chinese combinations, produced in strife toward fulfilling Mao Zedong's Communist-revolutionary vision, have a potential to represent a critical alterity to Western health policies, challenging rhetoric against such combinations. However, as is also noted in this article based on ethnographic fieldwork in East Africa, their potential alterity has been corroded for at least two reasons. First, the medical rationale for dispensing these medications has been shaped by commercial demands in ways that have worked toward transforming the formerly scholarly Chinese medical tradition (as outlined by Bates 1995) into a consumer-near and popular "folk medicine" (as defined by Farquhar 1994:212). Second, the repertoire of Chinese propriety medicines is impoverished as its efficacious "alternatively modern" drugs are being redefined as "modern" biomedical drugs. The article concludes that the potentially critical alterity of any formerly scholarly traditional medicine is more likely to be lost in those fields of health care that are both highly commercialized and polarized by the biomedical imperative to distinguish between "traditional" and "modern" medicines. As example for demonstrating how contentious the issue is, qinghaosu [image: see text] (artemisinin) is put center stage. It is an anti-malarial substance which in the 1970s Chinese scientists extracted from the Chinese medical drug qinghao [image: see text] (Herba Artemisiae

  5. Assessment of the effectiveness of the CD3+ tool to detect counterfeit and substandard anti-malarials.

    PubMed

    Batson, JaCinta S; Bempong, Daniel K; Lukulay, Patrick H; Ranieri, Nicola; Satzger, R Duane; Verbois, Leigh

    2016-02-25

    The US FDA recently developed CD3+, a counterfeit detection tool that is based on sample illumination at specific wavelengths of light and visual comparison of suspect sample and packaging materials to an authentic sample. To test performance of the CD3+ in field conditions, a study was conducted in Ghana which compared the CD3+ side-by-side with two existing medicine quality screening technologies-TruScan™ Portable Raman spectrometer and GPHF Minilab(®). A total of 84 anti-malarial test samples comprising artemether-lumefantrine tablets and artesunate-amodiaquine tablets were used. The technologies were evaluated for sensitivity in determining counterfeit/substandard (The term counterfeit or falsified is used in this article to refer to medicines that carry a false representation of identity or source or both. The term substandard is used to refer to medicines that do not meet the quality specifications given in the accepted pharmacopeia.) medicines, specificity in determining authentic products, and reliability of the results. Authentic samples obtained from manufacturers were used as reference standards. HPLC analysis data was used as the "gold standard" for decisions regarding a sample being authentic or substandard/counterfeit. CD3+ had a sensitivity of 1.00 in detecting counterfeit/substandard products compared to Minilab (0.79) and TruScan (0.79). CD3+ had a lower specificity (0.53) in determining authentic products compared to the specificities reached by Minilab (0.99) and TruScan (1.00). High sensitivity in this context means that the technology is effective in identifying substandard/counterfeit products whereas the low specificity means that the technique can sometimes mischaracterize good products as substandard/counterfeit. Examination of dosage units only (and not packaging) using CD3+ yielded improved specificity 0.64. When only assessment of sample identification was done, the TruScan provided sensitivity (1.00) and specificity (0.99); and the

  6. Synthesis and evaluation of phenoxyoxazaphospholidine, phenoxyoxazaphosphinane, and benzodioxaphosphininamine sulfides and related compounds as potential anti-malarial agents.

    PubMed

    Mara, Christine; Dempsey, Enda; Bell, Angus; Barlow, James W

    2013-06-15

    A series of phenoxyoxazaphospholidine, phenoxyoxazaphosphinane and benzodioxaphosphininamine sulfides and related cyclic organophosphorus compounds based on the lead anti-tubulin herbicides amiprophos methyl and butamifos were synthesised and evaluated for anti-malarial activity. Of these compounds, while none of the phenoxyoxazaphospholidines, phenoxyoxazaphosphinanes or benzodioxaphosphininamine sulphides were more potent than APM, phosphorothioamidate 30, a dual compound also bearing an aminoquinoline motif, showed promising activity against Plasmodium falciparum (IC50 0.038 μM) and warrants further study.

  7. Strategies for developing multi-epitope, subunit-based, chemically synthesized anti-malarial vaccines.

    PubMed

    Patarroyo, M E; Cifuentes, G; Bermúdez, A; Patarroyo, M A

    2008-10-01

    An anti-malarial vaccine against the extremely lethal Plasmodium falciparum is desperately needed. Peptides from this parasite's proteins involved in invasion and having high red blood cell-binding ability were identified; these conserved peptides were not immunogenic or protection-inducing when used for immunizing Aotus monkeys. Modifying some critical binding residues in these high-activiy binding peptides' (HABPs') attachment to red blood cells (RBC) allowed them to induce immunogenicity and protection against experimental challenge and acquire the ability to bind to specific HLA-DRp1* alleles. These modified HABPs adopted certain characteristic structural configurations as determined by circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) associated with certain HLA-DRbeta1* haplotype binding activities and characteristics, such as a 2-angstroms-distance difference between amino acids fitting into HLA-DRp1 Pockets 1 to 9, residues participating in binding to HLA-DR pockets and residues making contact with the TCR, suggesting haplotype and allele-conscious TCR. This has been demonstrated in HLA-DR-like genotyped monkeys and provides the basis for designing high effective, subunit-based, multi-antigen, multi-stage, synthetic vaccines, for immediate human use, malaria being one of them.

  8. Novel Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase with Anti-malarial Activity in the Mouse Model*

    PubMed Central

    Booker, Michael L.; Bastos, Cecilia M.; Kramer, Martin L.; Barker, Robert H.; Skerlj, Renato; Sidhu, Amar Bir; Deng, Xiaoyi; Celatka, Cassandra; Cortese, Joseph F.; Guerrero Bravo, Jose E.; Crespo Llado, Keila N.; Serrano, Adelfa E.; Angulo-Barturen, Iñigo; Jiménez-Díaz, María Belén; Viera, Sara; Garuti, Helen; Wittlin, Sergio; Papastogiannidis, Petros; Lin, Jing-wen; Janse, Chris J.; Khan, Shahid M.; Duraisingh, Manoj; Coleman, Bradley; Goldsmith, Elizabeth J.; Phillips, Margaret A.; Munoz, Benito; Wirth, Dyann F.; Klinger, Jeffrey D.; Wiegand, Roger; Sybertz, Edmund

    2010-01-01

    Plasmodium falciparum, the causative agent of the most deadly form of human malaria, is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and represents a potential target for anti-malarial therapy. A high throughput screen and subsequent medicinal chemistry program identified a series of N-alkyl-5-(1H-benzimidazol-1-yl)thiophene-2-carboxamides with low nanomolar in vitro potency against DHODH from P. falciparum, P. vivax, and P. berghei. The compounds were selective for the parasite enzymes over human DHODH, and x-ray structural data on the analog Genz-667348, demonstrated that species selectivity could be attributed to amino acid differences in the inhibitor-binding site. Compounds from this series demonstrated in vitro potency against the 3D7 and Dd2 strains of P. falciparum, good tolerability and oral exposure in the mouse, and ED50 values in the 4-day murine P. berghei efficacy model of 13–21 mg/kg/day with oral twice-daily dosing. In particular, treatment with Genz-667348 at 100 mg/kg/day resulted in sterile cure. Two recent analogs of Genz-667348 are currently undergoing pilot toxicity testing to determine suitability as clinical development candidates. PMID:20702404

  9. Novel Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase with Anti-malarial Activity in the Mouse Model

    SciTech Connect

    Booker, Michael L.; Bastos, Cecilia M.; Kramer, Martin L.; Barker, Jr., Robert H.; Skerlj, Renato; Sidhu, Amar Bir; Deng, Xiaoyi; Celatka, Cassandra; Cortese, Joseph F.; Guerrero Bravo, Jose E.; Crespo Llado, Keila N.; Serrano, Adelfa E.; Angulo-Barturen, Iñigo; Jiménez-Díaz, María Belén; Viera, Sara; Garuti, Helen; Wittlin, Sergio; Papastogiannidis, Petros; Lin, Jing-wen; Janse, Chris J.; Khan, Shahid M.; Duraisingh, Manoj; Coleman, Bradley; Goldsmith, Elizabeth J.; Phillips, Margaret A.; Munoz, Benito; Wirth, Dyann F.; Klinger, Jeffrey D.; Wiegand, Roger; Sybertz, Edmund

    2010-11-22

    Plasmodium falciparum, the causative agent of the most deadly form of human malaria, is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and represents a potential target for anti-malarial therapy. A high throughput screen and subsequent medicinal chemistry program identified a series of N-alkyl-5-(1H-benzimidazol-1-yl)thiophene-2-carboxamides with low nanomolar in vitro potency against DHODH from P. falciparum, P. vivax, and P. berghei. The compounds were selective for the parasite enzymes over human DHODH, and x-ray structural data on the analog Genz-667348, demonstrated that species selectivity could be attributed to amino acid differences in the inhibitor-binding site. Compounds from this series demonstrated in vitro potency against the 3D7 and Dd2 strains of P. falciparum, good tolerability and oral exposure in the mouse, and ED{sub 50} values in the 4-day murine P. berghei efficacy model of 13-21 mg/kg/day with oral twice-daily dosing. In particular, treatment with Genz-667348 at 100 mg/kg/day resulted in sterile cure. Two recent analogs of Genz-667348 are currently undergoing pilot toxicity testing to determine suitability as clinical development candidates.

  10. Effect of selenium (Se) deficiency on the anti-malarial action of Qinghaosu (QHS) in mice

    SciTech Connect

    Levander, O.A.; Ager, A.L.; May, R.

    1986-03-01

    QHS is an endoperoxide, so it occurred to the authors that its anti-malarial action might be potentiated by low glutathione peroxidase (GSH-Px) activity. Weanling female mice were fed 1 of 4 diets: chow or a Torula yeast-based diet supplemented with 0, 0.1 or 0.5 ppm Se as Na/sub 2/SeO/sub 3/. After 6 weeks, mean hepatic GSH-Px activities and plasma Se levels in these 4 dietary groups were 17.3, 0.1, 5.4, and 14.5 munits/mg protein and 242, 4, 230, and 532 ng/ml, respectively. At this time, all mice were inoculated i.p. with asexual blood stages of Plasmodium yoelii. Then groups of 7 or 8 mice fed each diet were given 0, 4, 16, or 64 mg QHS/kg orally bid at 3, 4, and 5 days post inoculation. On the 6th day, blood films were taken and antimalarial activity was assessed by determining % parasitemia (% PARA). Mice given 0 or 4 mg QHS/kg averaged 47% PARA and this was not affected by diet. Mice receiving 64 mg QHS/kg averaged about 1% PARA irrespective of diet. However, mice given 16 mg QHS/kg had 25% PARA when fed chow but only 8 to 11% PARA when fed the Torula diet, regardless of Se intake. Thus, while Se status did not appear to influence the antimalarial potency of QHS, some factor(s) in the Torula diet enhanced its activity at intermediate doses vs. the chow diet.

  11. The development and validation of an LC-MS/MS method for the determination of a new anti-malarial compound (TK900D) in human whole blood and its application to pharmacokinetic studies in mice

    PubMed Central

    2014-01-01

    Background Malaria is one of the most lethal and life-threatening killer infectious diseases in the world, and account for the deaths of more than half a million people annually. Despite the remarkable achievement made in preventing and eradicating malaria, it still remains a threat to the public health and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. Therefore, the need to develop new anti-malarial drugs is crucial. The chemistry department at the University of Cape Town synthesized a number of new CQ-like derivatives (TK-series), and evaluated them for in vitro activity against both CQ-sensitive and -resistant Plasmodium falciparum strains, and for general cytotoxicity against a Chinese Hamster Ovarian (CHO) mammalian cell line. The lead compounds from the TK-series were selected for a comprehensive pharmacokinetic (PK) evaluation in a mouse model. Methods A sensitive LC-MS/MS assay was developed for the quantitative determination of TK900D. Multiple reaction monitoring (MRM) in the positive ionization mode was used for detection. The analyte and the internal standard (TK900E) were isolated from blood samples by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved with a Phenomenex® Kinetex C18 (100 × 2.0 mm id, 2.6 μm) analytical column, using a mixture of 0.1% formic acid and acetonitrile (50:50; v/v) as the mobile phase. The method was fully validated over concentrations that ranged from 3.910 to 1000 ng/ml, and used to evaluate the PK properties of the lead compounds in a mouse model. Results The assay was robust, with deviation not exceeding 11% for the intra- and inter-run precision and accuracy. Extraction recovery was consistent and more than 60%. PK evaluation showed that TK900D and TK900E have moderate oral bioavailability of 30.8% and 25.9%, respectively. The apparent half-life ranged between 4 to 6 h for TK900D and 3.6 to 4 h for TK900E. Conclusion The assay was

  12. Innovative public-private partnerships to maximize the delivery of anti-malarial medicines: lessons learned from the ASAQ Winthrop experience.

    PubMed

    Bompart, François; Kiechel, Jean-René; Sebbag, Robert; Pecoul, Bernard

    2011-05-23

    This case study describes how a public-private partnership initiated to develop a new anti-malarial combination, ASAQ Winthrop, has evolved over time to address issues posed by its effective deployment in the field. In 2002, DNDi created the FACT project to develop two fixed-dose combinations, artesunate-amodiaquine and artesunate-mefloquine, to meet the WHO anti-malarial treatment recommendations and international regulatory agencies approval standards. In 2002, Sanofi-Aventis had started a development programme for a fixed-dose combination of artesunate and amodiaquine, to replace its co-blister combination. DNDi and Sanofi-Aventis joined forces in 2004, with the objective of developing within the shortest possible time frame a non-patented, affordable and easy to use fixed-dose combination of artesunate and amodiaquine adapted to the needs of patients, in particular, those of children. The partners developed Coarsucam®/Artesunate Amodiaquine Winthrop® ("ASAQ Winthrop") which was prequalified by the WHO in 2008. Additional partnerships have since been established by DNDi and Sanofi-Aventis to ensure: 1) the adoption of this new medicine by malaria-endemic countries, 2) its appropriate usage through a broad range of information tools, and 3) the monitoring of its safety and efficacy in the field through an innovative Risk Management Plan. The partnership between DNDi and Sanofi-Aventis has enabled the development and pre-qualification of ASAQ Winthrop in a short timeframe. As a result of the multiple collaborations established by the two partners, as of late 2010, ASAQ Winthrop was registered in 30 sub-Saharan African countries and in India, with over 80 million treatments distributed in 21 countries. To date, 10 clinical studies, involving 3432 patients with ASAQ Winthrop were completed to document efficacy and safety issues identified in the Risk Management Plan. The speed at which ASAQ Winthrop was adopted in the field shows that this drug fits the needs of

  13. Gel versus capillary electrophoresis genotyping for categorizing treatment outcomes in two anti-malarial trials in Uganda

    PubMed Central

    2010-01-01

    Background Molecular genotyping is performed in anti-malarial trials to determine whether recurrent parasitaemia after therapy represents a recrudescence (treatment failure) or new infection. The use of capillary instead of agarose gel electrophoresis for genotyping offers technical advantages, but it is unclear whether capillary electrophoresis will result in improved classification of anti-malarial treatment outcomes. Methods Samples were genotyped using both gel and capillary electrophoresis from randomized trials of artemether-lumefantrine (AL) vs. dihydroartemisinin-piperaquine (DP) performed in two areas of Uganda: Kanungu, where transmission is moderate, and Apac, where transmission is very high. Both gel and capillary methods evaluated polymorphic regions of the merozoite surface protein 1 and 2 and glutamine rich protein genes. Results Capillary electrophoresis detected more alleles and provided higher discriminatory power than agarose gel electrophoresis at both study sites. There was only moderate agreement between classification of outcomes with the two methods in Kanungu (kappa = 0.66) and poor agreement in Apac (kappa = 0.24). Overall efficacy results were similar when using gel vs. capillary methods in Kanungu (42-day risk of treatment failure for AL: 6.9% vs. 5.5%, p = 0.4; DP 2.4% vs. 2.9%, p = 0.5). However, the measured risk of recrudescence was significantly higher when using gel vs. capillary electrophoresis in Apac (risk of treatment failure for AL: 17.0% vs. 10.7%, p = 0.02; DP: 8.5% vs. 3.4%, p = 0.03). Risk differences between AL and DP were not significantly different whether gel or capillary methods were used. Conclusions Genotyping with gel electrophoresis overestimates the risk of recrudescence in anti-malarial trials performed in areas of high transmission intensity. Capillary electrophoresis provides more accurate outcomes for such trials and should be performed when possible. In areas of moderate transmission, gel electrophoresis

  14. From fever to anti-malarial: the treatment-seeking process in rural Senegal

    PubMed Central

    2010-01-01

    Background Currently less than 15% of children under five with fever receive recommended artemisinin-combination therapy (ACT), far short of the Roll Back Malaria target of 80%. To understand why coverage remains low, it is necessary to examine the treatment pathway from a child getting fever to receiving appropriate treatment and to identify critical blockages. This paper presents the application of such a diagnostic approach to the coverage of prompt and effective treatment of children with fever in rural Senegal. Methods A two-stage cluster sample household survey was conducted in August 2008 in Tambacounda, Senegal, to investigate treatment behaviour for children under five with fever in the previous two weeks. The treatment pathway was divided in to five key steps; the proportion of all febrile children reaching each step was calculated. Results were stratified by sector of provider (public, community, and retail). Logistic regression was used to determine predictors of treatment seeking. Results Overall 61.6% (188) of caretakers sought any advice or treatment and 40.3% (123) sought any treatment promptly within 48 hours. Over 70% of children taken to any provider with fever did not receive an anti-malarial. The proportion of febrile children receiving ACT within 48 hours was 6.2% (19) from any source; inclusion of correct dose and duration reduced this to 1.3%. The proportion of febrile children receiving ACT within 48 hours (not including dose & duration) was 3.0% (9) from a public provider, 3.0% (9) from a community source and 0.3% (1) from the retail sector. Inclusion of confirmed diagnosis within the public sector treatment pathway as per national policy increases the proportion of children receiving appropriate treatment with ACT in this sector from 9.4% (9/96) to an estimated 20.0% (9/45). Conclusions Process analysis of the treatment pathway for febrile children must be stratified by sector of treatment-seeking. In Tambacounda, Senegal, interventions

  15. Docking Based 3D-QSAR Study of Tricyclic Guanidine Analogues of Batzelladine K as anti-malarial agents

    NASA Astrophysics Data System (ADS)

    Ahmed, Nafees; Anwar, Sirajudheen; Thet Htar, Thet

    2017-06-01

    The Plasmodium falciparum Lactate Dehydrogenase enzyme (PfLDH) catalyzes inter-conversion of pyruvate to lactate during glycolysis producing the energy required for parasitic growth. The PfLDH has been studied as a potential molecular target for development of anti-malarial agents. In an attempt to find the potent inhibitor of PfLDH, we have used Discovery studio to perform molecular docking in the active binding pocket of PfLDH by CDOCKER, followed by three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of tricyclic guanidine batzelladine compounds, which were previously synthesized in our laboratory. Docking studies showed that there is a very strong correlation between in silico and in vitro results. Based on docking results, a highly predictive 3D-QSAR model was developed with q2 of 0.516. The model has predicted r2 of 0.91 showing that predicted IC50 values are in good agreement with experimental IC50 values. The results obtained from this study revealed the developed model can be used to design new anti-malarial compounds based on tricyclic guanidine derivatives and to predict activities of new inhibitors.

  16. Skeletal hybridization and PfRIO-2 kinase modeling for synthesis of α-pyrone analogs as anti-malarial agent.

    PubMed

    Parveen, Afsana; Chakraborty, Arnish; Konreddy, Ananda Kumar; Chakravarty, Harapriya; Sharon, Ashoke; Trivedi, Vishal; Bal, Chandralata

    2013-01-01

    The pharmacophoric hybridization and computational design approach were applied to generate a novel series of α-pyrone analogs as plausible anti-malarial lead candidate. A putative active site in flexible loop close to wing-helix domain of PfRIO2 kinase was explored computationally to understand the molecular basis of ligand binding. All the synthesized molecules (3a-g) exhibited in vitro antimalarial activity. Oxidative stress induced by 3a-d were calculated and found to be significantly higher in case of 3b. Therefore, 3b, which shown most significant result was identified as promising lead for further SAR study to develop potent anti-malarials.

  17. Combination treatment of glioblastoma multiforme cell lines with the anti-malarial artesunate and the epidermal growth factor receptor tyrosine kinase inhibitor OSI-774.

    PubMed

    Efferth, Thomas; Ramirez, Tzutzuy; Gebhart, Erich; Halatsch, Marc-Eric

    2004-05-01

    New drugs and combination modalities for otherwise non-responsive brain tumors are urgently required. The anti-malarial artesunate (ART) and the EGFR tyrosine kinase inhibitor OSI-774 reveal profound cytotoxic activity. The effectiveness of a combination treatment and the underlying molecular determinants of cellular response are unknown. In the present investigation, we studied ART and OSI-774 in glioblastoma multiforme (GBM) cell lines. Supra-additive inhibition of cell growth was observed in U-87MG.DeltaEGFR cells transduced with a deletion-mutant constitutively active EGFR gene, while additive effects were present in cells transduced with wild-type EGFR (U-87MG.WT-2N), kinase-deficient EGFR (U-87MG.DK-2N), mock vector controls (U-87MG.LUX), or non-transduced parental U-87MG cells. Among nine other non-transduced GBM cell lines, supra-additive effects were found in two cell lines (G-210GM, G-599GM), while ART and OSI-774 acted in an additive manner in the other seven cell lines (G-211GM, G-750GM, G-1163GM, G-1187GM, G-1265GM, G-1301GM, and G-1408GM). Sub-additive or antagonistic effects were not observed. Genomic gains and losses of genetic material in the non-transduced cell lines as assessed by comparative genomic hybridization were correlated with the IC(50) values for ART and OSI-774 and subsequently subjected to hierarchical cluster analysis and cluster image mapping. A genomic profile of imbalances was detected that predicted cellular response to ART and OSI-774. The genes located at the genomic imbalances of interest may serve as candidate resistance genes of GBM cells towards ART and OSI-774. In conclusion, the combination treatment of ART and OSI-774 resulted in an increased growth inhibition of GBM cell lines as compared to each drug alone.

  18. Synthesis, biophysical, and biological studies of wild-type and mutant psalmopeotoxins--anti-malarial cysteine knot peptides from Psalmopoeus cambridgei.

    PubMed

    Kamolkijkarn, Pacharin; Prasertdee, Thitawan; Netirojjanakul, Chawita; Sarnpitak, Pakornwit; Ruchirawat, Somsak; Deechongkit, Songpon

    2010-04-01

    Psalmopeotoxin I and II (PcFK1 and PcFK2), an anti-malarial peptide first extracted from Psalmopoeus cambridgei was synthesized and characterized. Both peptides belong to the Inhibitor Cystine Knot (ICK) superfamily, containing three disulfide bridges. The six cysteine residues are conserved similar to other members of the ICK superfamily, suggesting their critical role for either folding or function. In this study, the peptides were synthesized using Fmoc solid-phase peptide synthesis (SPPS). The three disulfide bonds of were constructed by regioselective and random oxidative approaches. The resulting disulfide bond patterns were verified by the HPLC-MS analysis of intact peptides and by the disulfide bond mapping using tryptic digestion. Implications of the disulfide bonds on the biophysical and biological properties of PcFKs were studied using three disulfide mutants in which a particular pair of cysteines was replaced with two isosteric serine residues. Structures and biophysical characteristics of all variants were studied using far-UV CD and fluorescence spectroscopy. Biological activities of all variants were evaluated using antiplasmodial assay against the K1 multi-drug-resistant strain of P. falciparum. The experimental results showed that the three disulfide bridges could not be correctly synthesized by the random oxidative strategy. Structural and biophysical analyses revealed that all variants had similar structures to the twisted beta-sheet. However, the studies of disulfide bond removal indicated that each disulfide bond had different effects on both biophysical and biological activities of PcFKs. Correlation of biophysical parameters and biological activities showed that both PcFKs may have different mechanisms of actions for antiplasmodial activity.

  19. Anti-malarials exert a protective effect while Mestizo patients are at increased risk of developing SLE renal disease: data from a Latin-American cohort

    PubMed Central

    Pons-Estel, Guillermo J.; Alarcón, Graciela S.; Hachuel, Leticia; Boggio, Gabriela; Wojdyla, Daniel; Pascual-Ramos, Virginia; Soriano, Enrique R.; Saurit, Verónica; Cavalcanti, Fernando S.; Guzman, Renato A.; Guibert-Toledano, Marlene; Sauza del Pozo, Maria J.; Amigo, Mary-Carmen; Alva, Magaly; Esteva-Spinetti, Maria H.

    2012-01-01

    Objective. To examine the role of ethnicity and the use of anti-malarials (protective) on lupus renal disease. Methods. A nested case–control study (1:2 proportion, n = 265 and 530) within GLADEL's (Grupo Latino Americano De Estudio de Lupus) longitudinal inception cohort was carried out. The end-point was ACR renal criterion development after diagnosis. Cases and controls were matched for follow-up time (end-point or a comparable time, respectively). Renal disease predictors were examined by univariable and multivariable analyses. Additional analyses were done to determine if the protective effect of anti-malarials persisted after adjusting for intake-associated confounders. Results. Of the cases, 233 (87.9%) were women; their mean (s.d.) age at diagnosis was 28.0 (11.9) years and their median (Q3–Q1 interquartile range) follow-up time for cases and controls was 8.3 months (Q3–Q1: 23.5); 56.6% of the cases and 74.3% of the controls were anti-malarial users. Mestizo ethnicity [odds ratio (OR) 1.72, 95% CI 1.19, 2.48] and hypertension (OR 2.26, 95% CI 1.38, 3.70) were independently associated with a higher risk of renal disease, whereas anti-malarial use (OR 0.39, 95% CI 0.26, 0.58), older age at disease onset (OR 0.98, 95% CI 0.96, 0.99) and female gender (OR 0.56, 95% CI 0.32, 0.99) were negatively associated with such occurrence. After adjusting for variables associated with their intake, the protective effect of anti-malarials on renal disease occurrence persisted (OR 0.38, 95% CI 0.25, 0.58). Conclusion. Mestizo patients are at increased risk of developing renal disease, whereas anti-malarial use protects patients from such an occurrence. PMID:22389125

  20. Context Sensitive Modeling of Cancer Drug Sensitivity

    PubMed Central

    Chen, Bo-Juen; Litvin, Oren; Ungar, Lyle; Pe’er, Dana

    2015-01-01

    Recent screening of drug sensitivity in large panels of cancer cell lines provides a valuable resource towards developing algorithms that predict drug response. Since more samples provide increased statistical power, most approaches to prediction of drug sensitivity pool multiple cancer types together without distinction. However, pan-cancer results can be misleading due to the confounding effects of tissues or cancer subtypes. On the other hand, independent analysis for each cancer-type is hampered by small sample size. To balance this trade-off, we present CHER (Contextual Heterogeneity Enabled Regression), an algorithm that builds predictive models for drug sensitivity by selecting predictive genomic features and deciding which ones should—and should not—be shared across different cancers, tissues and drugs. CHER provides significantly more accurate models of drug sensitivity than comparable elastic-net-based models. Moreover, CHER provides better insight into the underlying biological processes by finding a sparse set of shared and type-specific genomic features. PMID:26274927

  1. Activity of Clinically Relevant Antimalarial Drugs on Plasmodium falciparum Mature Gametocytes in an ATP Bioluminescence “Transmission Blocking” Assay

    PubMed Central

    Lozano, Sonia; Miguel, Celia; Franco, Virginia; Leroy, Didier; Herreros, Esperanza

    2012-01-01

    Background Current anti-malarial drugs have been selected on the basis of their activity against the symptom-causing asexual blood stage of the parasite. Which of these drugs also target gametocytes, in the sexual stage responsible for disease transmission, remains unknown. Blocking transmission is one of the main strategies in the eradication agenda and requires the identification of new molecules that are active against gametocytes. However, to date, the main limitation for measuring the effect of molecules against mature gametocytes on a large scale is the lack of a standardized and reliable method. Here we provide an efficient method to produce and purify mature gametocytes in vitro. Based on this new procedure, we developed a robust, affordable, and sensitive ATP bioluminescence-based assay. We then assessed the activity of 17 gold-standard anti-malarial drugs on Plasmodium late stage gametocytes. Methods and Findings Difficulties in producing large amounts of gametocytes have limited progress in the development of malaria transmission blocking assays. We improved the method established by Ifediba and Vanderberg to obtain viable, mature gametocytes en masse, whatever the strain used. We designed an assay to determine the activity of antimalarial drugs based on the intracellular ATP content of purified stage IV–V gametocytes after 48 h of drug exposure in 96/384-well microplates. Measurements of drug activity on asexual stages and cytotoxicity on HepG2 cells were also obtained to estimate the specificity of the active drugs. Conclusions The work described here represents another significant step towards determination of the activity of new molecules on mature gametocytes of any strain with an automated assay suitable for medium/high-throughput screening. Considering that the biology of the forms involved in the sexual and asexual stages is very different, a screen of our 2 million-compound library may allow us to discover novel anti-malarial drugs to target

  2. A Systematic Review of Anti-malarial Properties, Immunosuppressive Properties, Anti-inflammatory Properties, and Anti-cancer Properties of Artemisia Annua.

    PubMed

    Alesaeidi, Samira; Miraj, Sepide

    2016-10-01

    Artemisia annua belongs to the asteraceae family, indigenous to the mild climate of Asia. The aim of this study was to overview its anti-malarial properties, immunosuppressive properties, anti-inflammatory properties and anti-cancer properties. This systematic review was carried out by searching studies in PubMed, Medline, Web of Science, and IranMedex databases. The initial search strategy identified approximately ninety eight references. In this study, forty six studies were accepted for further screening and met all of our inclusion. The search terms were "Artemisia annua", "therapeutic properties", "and pharmacological effects". Artemisia annua is commonly used for its anti-malarial, immunosuppressive anti-inflammatory properties. Artemisia annua contributes to the treatment of various diseases such as diabetes, heart diseases, arthritis and eczema and possesses various effects such as antibacterial, antioxidant, anticoccidial, and antiviral effects. Furthermore, it was said to be good for cancer treatment. In this study, anti-malarial, immunosuppressive, anti-inflammatory properties of this plant are presented using published articles in scientific sites.

  3. A Systematic Review of Anti-malarial Properties, Immunosuppressive Properties, Anti-inflammatory Properties, and Anti-cancer Properties of Artemisia Annua

    PubMed Central

    Alesaeidi, Samira; Miraj, Sepide

    2016-01-01

    Artemisia annua belongs to the asteraceae family, indigenous to the mild climate of Asia. The aim of this study was to overview its anti-malarial properties, immunosuppressive properties, anti-inflammatory properties and anti-cancer properties. This systematic review was carried out by searching studies in PubMed, Medline, Web of Science, and IranMedex databases. The initial search strategy identified approximately ninety eight references. In this study, forty six studies were accepted for further screening and met all of our inclusion. The search terms were “Artemisia annua”, “therapeutic properties”, “and pharmacological effects”. Artemisia annua is commonly used for its anti-malarial, immunosuppressive anti-inflammatory properties. Artemisia annua contributes to the treatment of various diseases such as diabetes, heart diseases, arthritis and eczema and possesses various effects such as antibacterial, antioxidant, anticoccidial, and antiviral effects. Furthermore, it was said to be good for cancer treatment. In this study, anti-malarial, immunosuppressive, anti-inflammatory properties of this plant are presented using published articles in scientific sites. PMID:27957318

  4. Enhancement of heme-induced membrane damage by the anti-malarial clotrimazole: the role of colloid-osmotic forces.

    PubMed

    Huy, Nguyen Tien; Takano, Ryo; Hara, Saburo; Kamei, Kaeko

    2004-03-01

    Two recent studies have demonstrated that clotrimazole, a well-known potential antifungal agent, inhibits the in vitro growth of chloroquine-resistant strains of the malaria parasite, Plasmodium falciparum. In a previous study, we suggested that clotrimazole acts as an anti-malarial agent by inhibiting heme catabolism in the malaria parasite and by enhancing heme-induced membrane damage. In this paper, we examined the mechanism of action by measuring hemolysis as an indicator of membrane damage. Our results showed that clotrimazole does not promote the binding of heme to membranes, and that the enhancement of heme-induced hemolysis by clotrimazole is not caused by lipid peroxidation or by oxidation of thiol groups in membrane proteins. Instead, clotrimazole inhibits glutathione-dependent heme degradation, resulting in an enhancement of heme-induced hemolysis. We also found that clotrimazole increases the susceptibility of erythrocytes to hypotonic lysis in the presence of heme and that sucrose could inhibit hemolysis induced by heme-clotrimazole complexes. Thus, it appears that the enhancement of heme-induced hemolysis by clotrimazole in our experiments is due to a colloid osmotic hemolysis mechanism. The hydrophobicity and the large molecular size of the heme-clotrimazole complex might be key factors for induction of hemolysis.

  5. Development and evaluation of anti-malarial bio-conjugates: artesunate-loaded nanoerythrosomes.

    PubMed

    Agnihotri, Jaya; Saraf, Shubhini; Singh, Sobhna; Bigoniya, Papiya

    2015-10-01

    Biodegradable cellular carrier has desired properties for achieving effective long-term controlled release of drugs having short half life. To reduce the undesired effects of drug, advanced drug delivery systems are needed which are based on specific cell targeting module. Artesunate (ART) conjugation on nanoerythrosomes (NE) can have controlled delivery to avoid drug leakage, increase the stability, and reduce cost and toxicities. In this study nanosized lipoprotein membrane vesicles bearing ART were prepared by extrusion method. Developed ART-NE conjugate formulations were optimized on the basis of vesicle morphology, size and size distribution, polydispersity index, integrity of membrane, loaded drug concentration, drug leakage, effect of temperature and viscosity, syringeability, in vitro release profile and in vivo plasma concentration estimation studies. Fourier transform infrared (FTIR) spectroscopy reveals that lipid chain order of RBCs are insignificantly affected in moderate conditions after ART loading. The formulated ART-NE carrier revealed non aggregated, uniformly sized particles with smooth surfaces. The maximum drug loading was found to be 25.20 ± 1.3 μg/ml. ART-NE formulation was best fit for zero order kinetics and was found to be capable of controlled release of drug for 8 hrs. ART-NE formulation showed good redispersibility with desirable properties for parenteral administration. Formulation was stable when subjected to stress by centrifugal force of 7500 rpm and could bear turbulence shock of 15 passes from hypodermic needle of size 23 gauges. The ART-NE formulation administered intravenously showed higher plasma concentration compared to free drug signifying not only controlled release but higher rate of in vivo release. The developed formulation exhibited zero order release profile as per kinetic study analysis suggesting the suitability of carrier for the sustained and targeted delivery of ART. The developed ART-NE drug delivery system

  6. Discovery of anti-malarial agents through application of in silico studies.

    PubMed

    Barmade, Mahesh A; Murumkar, Prashant R; Sharma, Mayank Kumar; Shingala, Kaushik P; Giridhar, Rajani R; Yadav, Mange Ram

    2015-01-01

    Among the various parasitic diseases, malaria is the deadliest one. Due to the emergence of high drug resistance to the existing drug candidates there is a global need for development of new drug candidates which will be effective against resistant strains of malaria parasite. In silico molecular modeling approaches have been playing an important role in the discovery of novel lead molecules having antimalarial activity. Present review is an effort to cover all the developments related to the application of computational techniques for the design and discovery of novel antimalarial compounds since the year 2011 onwards.

  7. Mind the gaps - the epidemiology of poor-quality anti-malarials in the malarious world - analysis of the WorldWide Antimalarial Resistance Network database

    PubMed Central

    2014-01-01

    Background Poor quality medicines threaten the lives of millions of patients and are alarmingly common in many parts of the world. Nevertheless, the global extent of the problem remains unknown. Accurate estimates of the epidemiology of poor quality medicines are sparse and are influenced by sampling methodology and diverse chemical analysis techniques. In order to understand the existing data, the Antimalarial Quality Scientific Group at WWARN built a comprehensive, open-access, global database and linked Antimalarial Quality Surveyor, an online visualization tool. Analysis of the database is described here, the limitations of the studies and data reported, and their public health implications discussed. Methods The database collates customized summaries of 251 published anti-malarial quality reports in English, French and Spanish by time and location since 1946. It also includes information on assays to determine quality, sampling and medicine regulation. Results No publicly available reports for 60.6% (63) of the 104 malaria-endemic countries were found. Out of 9,348 anti-malarials sampled, 30.1% (2,813) failed chemical/packaging quality tests with 39.3% classified as falsified, 2.3% as substandard and 58.3% as poor quality without evidence available to categorize them as either substandard or falsified. Only 32.3% of the reports explicitly described their definitions of medicine quality and just 9.1% (855) of the samples collected in 4.6% (six) surveys were conducted using random sampling techniques. Packaging analysis was only described in 21.5% of publications and up to twenty wrong active ingredients were found in falsified anti-malarials. Conclusions There are severe neglected problems with anti-malarial quality but there are important caveats to accurately estimate the prevalence and distribution of poor quality anti-malarials. The lack of reports in many malaria-endemic areas, inadequate sampling techniques and inadequate chemical analytical methods and

  8. Mind the gaps--the epidemiology of poor-quality anti-malarials in the malarious world--analysis of the WorldWide Antimalarial Resistance Network database.

    PubMed

    Tabernero, Patricia; Fernández, Facundo M; Green, Michael; Guerin, Philippe J; Newton, Paul N

    2014-04-08

    Poor quality medicines threaten the lives of millions of patients and are alarmingly common in many parts of the world. Nevertheless, the global extent of the problem remains unknown. Accurate estimates of the epidemiology of poor quality medicines are sparse and are influenced by sampling methodology and diverse chemical analysis techniques. In order to understand the existing data, the Antimalarial Quality Scientific Group at WWARN built a comprehensive, open-access, global database and linked Antimalarial Quality Surveyor, an online visualization tool. Analysis of the database is described here, the limitations of the studies and data reported, and their public health implications discussed. The database collates customized summaries of 251 published anti-malarial quality reports in English, French and Spanish by time and location since 1946. It also includes information on assays to determine quality, sampling and medicine regulation. No publicly available reports for 60.6% (63) of the 104 malaria-endemic countries were found. Out of 9,348 anti-malarials sampled, 30.1% (2,813) failed chemical/packaging quality tests with 39.3% classified as falsified, 2.3% as substandard and 58.3% as poor quality without evidence available to categorize them as either substandard or falsified. Only 32.3% of the reports explicitly described their definitions of medicine quality and just 9.1% (855) of the samples collected in 4.6% (six) surveys were conducted using random sampling techniques. Packaging analysis was only described in 21.5% of publications and up to twenty wrong active ingredients were found in falsified anti-malarials. There are severe neglected problems with anti-malarial quality but there are important caveats to accurately estimate the prevalence and distribution of poor quality anti-malarials. The lack of reports in many malaria-endemic areas, inadequate sampling techniques and inadequate chemical analytical methods and instrumental procedures emphasizes the

  9. Anti-malarial prescriptions in three health care facilities after the emergence of chloroquine resistance in Niakhar, Senegal (1992–2004)

    PubMed Central

    Munier, Aline; Diallo, Aldiouma; Cot, Michel; Ndiaye, Ousmane; Arduin, Pascal; Chippaux, Jean-Philippe

    2009-01-01

    Background In the rural zone of Niakhar in Senegal, the first therapeutic failures for chloroquine (CQ) were observed in 1992. In 2003, the national policy regarding first-line treatment of uncomplicated malaria was modified, replacing CQ by a transitory bi-therapy amodiaquine/sulphadoxine-pyrimethamine (AQ/SP), before the implementation of artemisinin-based combination therapy (ACT) in 2006. The aims of the study were to assess the evolution of anti-malarial prescriptions in three health care facilities between 1992 and 2004, in parallel with increasing CQ resistance in the region. Methods The study was conducted in the area of Niakhar, a demographic surveillance site located in a sahelo-sudanese region of Senegal, with mesoendemic and seasonal malaria transmission. Health records of two public health centres and a private catholic dispensary were collected retrospectively to cover the period 1992–2004. Results Records included 110,093 consultations and 292,965 prescribed treatments. Twenty-five percent of treatments were anti-malarials, prescribed to 49% of patients. They were delivered all year long, but especially during the rainy season, and 20% of patients with no clinical malaria diagnosis received anti-malarials. Chloroquine and quinine represented respectively 55.7% and 34.6% of prescribed anti-malarials. Overall, chloroquine prescriptions rose from 1992 to 2000, in parallel with clinical malaria; then the CQ prescription rate decreased from 2000 and was concomitant with the rise of SP and the persistence of quinine use. AQ and SP were mainly used as bi-therapy after 2003, at the time of national treatment policy change. Conclusion The results show the overall level of anti-malarial prescription in the study area for a considerable number of patients over a large period of time. Even though resistance to CQ rapidly increased from 1992 to 2001, no change in CQ prescription was observed until the early 2000s, possibly due to the absence of an obvious

  10. Got ACTs? Availability, price, market share and provider knowledge of anti-malarial medicines in public and private sector outlets in six malaria-endemic countries.

    PubMed

    O'Connell, Kathryn A; Gatakaa, Hellen; Poyer, Stephen; Njogu, Julius; Evance, Illah; Munroe, Erik; Solomon, Tsione; Goodman, Catherine; Hanson, Kara; Zinsou, Cyprien; Akulayi, Louis; Raharinjatovo, Jacky; Arogundade, Ekundayo; Buyungo, Peter; Mpasela, Felton; Adjibabi, Chérifatou Bello; Agbango, Jean Angbalu; Ramarosandratana, Benjamin Fanomezana; Coker, Babajide; Rubahika, Denis; Hamainza, Busiku; Chapman, Steven; Shewchuk, Tanya; Chavasse, Desmond

    2011-10-31

    Artemisinin-based combination therapy (ACT) is the first-line malaria treatment throughout most of the malaria-endemic world. Data on ACT availability, price and market share are needed to provide a firm evidence base from which to assess the current situation concerning quality-assured ACT supply. This paper presents supply side data from ACTwatch outlet surveys in Benin, the Democratic Republic of Congo (DRC), Madagascar, Nigeria, Uganda and Zambia. Between March 2009 and June 2010, nationally representative surveys of outlets providing anti-malarials to consumers were conducted. A census of all outlets with the potential to provide anti-malarials was conducted in clusters sampled randomly. 28,263 outlets were censused, 51,158 anti-malarials were audited, and 9,118 providers interviewed. The proportion of public health facilities with at least one first-line quality-assured ACT in stock ranged between 43% and 85%. Among private sector outlets stocking at least one anti-malarial, non-artemisinin therapies, such as chloroquine and sulphadoxine-pyrimethamine, were widely available (> 95% of outlets) as compared to first-line quality-assured ACT (< 25%). In the public/not-for-profit sector, first-line quality-assured ACT was available for free in all countries except Benin and the DRC (US$1.29 [Inter Quartile Range (IQR): $1.29-$1.29] and $0.52[IQR: $0.00-$1.29] per adult equivalent dose respectively). In the private sector, first-line quality-assured ACT was 5-24 times more expensive than non-artemisinin therapies. The exception was Madagascar where, due to national social marketing of subsidized ACT, the price of first-line quality-assured ACT ($0.14 [IQR: $0.10, $0.57]) was significantly lower than the most popular treatment (chloroquine, $0.36 [IQR: $0.36, $0.36]). Quality-assured ACT accounted for less than 25% of total anti-malarial volumes; private-sector quality-assured ACT volumes represented less than 6% of the total market share. Most anti-malarials were

  11. Got ACTs? Availability, price, market share and provider knowledge of anti-malarial medicines in public and private sector outlets in six malaria-endemic countries

    PubMed Central

    2011-01-01

    Background Artemisinin-based combination therapy (ACT) is the first-line malaria treatment throughout most of the malaria-endemic world. Data on ACT availability, price and market share are needed to provide a firm evidence base from which to assess the current situation concerning quality-assured ACT supply. This paper presents supply side data from ACTwatch outlet surveys in Benin, the Democratic Republic of Congo (DRC), Madagascar, Nigeria, Uganda and Zambia. Methods Between March 2009 and June 2010, nationally representative surveys of outlets providing anti-malarials to consumers were conducted. A census of all outlets with the potential to provide anti-malarials was conducted in clusters sampled randomly. Results 28,263 outlets were censused, 51,158 anti-malarials were audited, and 9,118 providers interviewed. The proportion of public health facilities with at least one first-line quality-assured ACT in stock ranged between 43% and 85%. Among private sector outlets stocking at least one anti-malarial, non-artemisinin therapies, such as chloroquine and sulphadoxine-pyrimethamine, were widely available (> 95% of outlets) as compared to first-line quality-assured ACT (< 25%). In the public/not-for-profit sector, first-line quality-assured ACT was available for free in all countries except Benin and the DRC (US$1.29 [Inter Quartile Range (IQR): $1.29-$1.29] and $0.52[IQR: $0.00-$1.29] per adult equivalent dose respectively). In the private sector, first-line quality-assured ACT was 5-24 times more expensive than non-artemisinin therapies. The exception was Madagascar where, due to national social marketing of subsidized ACT, the price of first-line quality-assured ACT ($0.14 [IQR: $0.10, $0.57]) was significantly lower than the most popular treatment (chloroquine, $0.36 [IQR: $0.36, $0.36]). Quality-assured ACT accounted for less than 25% of total anti-malarial volumes; private-sector quality-assured ACT volumes represented less than 6% of the total market share

  12. [Development of anti-malarial vaccines and need for clinical trials in accordance with international standards in South Africa].

    PubMed

    Doumbo, O K; Djimdé, A A; Théra, M A

    2008-06-01

    In the 20th century malaria remains a major problem of public health in sub-Saharan Africa. This haemosporidium discovered in Africa by Laveran in 1880, kills one child every 30 seconds which amounts to three "tsunami" flowing each year into the African continent. The current international solidarity raises new hopes as regards the possibility to suppress the morbidity effects on the population's health condition. In order to be efficient, today's strategies (impregnated mosquito nets, intermittent preventive treatments, artemisinin based combination therapy) should reach at least 80% of the targeted population (pregnant women and children). By 2025, the uncontrolled urbanization of the African population and the social disorders will make a new population a target for malaria. The new data of functional genomics and proteonics open new avenues of research for new mechanisms, new therapeutics and vaccine targets and new tools of diagnosis and prognosis. The current candidate vaccines of the first generation have allowed the development of African competences in clinical trials of international standard. Although they represent scientific advances they will not resolve the problem of public health. Research on candidate vaccines of 2nd and 3rd generation remains a challenge for the international scientific community. Africa should play a determining role in this process. Scientific information on the field remains essential for these generations of new anti-malarial vaccines. The ethical aspects regarding those clinical trials and actions of public health and research remain an universal necessity Deontology and ethics are two complementary approaches for the good practice of medicine and research of a good practitioner. For the protection and advantages of the patient and/or volunteer of the research are the cornerstones of the ethical approach. The scientific quality of a research protocol submitted to an independent research ethics committee and the volunteer 's

  13. Anti-malarial activity of a non-piperidine library of next-generation quinoline methanols

    PubMed Central

    2010-01-01

    Background The clinical utility for mefloquine has been eroded due to its association with adverse neurological effects. Better-tolerated alternatives are required. The objective of the present study was the identification of lead compounds that are as effective as mefloquine, but exhibit physiochemical properties likely to render them less susceptible to passage across the blood-brain barrier. Methods A library of drug-like non-piperidine analogs of mefloquine was synthesized. These compounds are diverse in structure and physiochemical properties. They were screened in appropriate in vitro assays and evaluated in terms of their potential as lead compounds. The correlation of specific structural attributes and physiochemical properties with activity was assessed. Results The most potent analogs were low molecular weight unconjugated secondary amines with no heteroatoms in their side-chains. However, these compounds were more metabolically labile and permeable than mefloquine. In terms of physiochemical properties, lower polar surface area, lower molecular weight, more freely rotatable bonds and fewer H-bond acceptors were associated with greater potency. There was no such relationship between activity and LogP, LogD or the number of hydrogen bond donors (HBDs). The addition of an H-bond donor to the side-chain yielded a series of active diamines, which were as metabolically stable as mefloquine but showed reduced permeability. Conclusions A drug-like library of non-piperidine analogs of mefloquine was synthesized. From amongst this library an active lead series of less permeable, but metabolically stable, diamines was identified. PMID:20149249

  14. Anti-malarial seroprevalence assessment during an elimination programme in Chabahar District, south-eastern Iran.

    PubMed

    Zakeri, Sedigheh; van den Hoogen, Lotus Leonie; Mehrizi, Akram Abouie; Karimi, Fatemh; Raeisi, Ahmad; Drakeley, Chris

    2016-07-22

    Iran has achieved a substantial decline in malaria incidence over the past decades. A common feature of malaria-endemic settings is the requirement for more sensitive techniques to describe levels of low transmission. In this study, serological and parasitological methods were used to measure transmission levels of Plasmodium falciparum and Plasmodium vivax during an elimination programme (2012) in Chabahar District, Sistan and Baluchistan Province, south-eastern Iran. Participants were randomly selected from 64 different geographical clusters in Chabahar city and surrounding villages. Antibody responses to P. falciparum and P. vivax blood-stage antigens were assessed by ELISA, while microscopy and molecular testing were used to determine parasite carriage by species. Age-adjusted antibody responses were analysed using a reversible catalytic model to calculate seroconversion rates (SCR). There was no evidence of recent transmission in the study areas, indicated by an absence of parasite infections in all ages and low or absent serological responses to either species in young children. The best model for age P. falciparum seroconversion was one with a change in exposure 21 years before sampling was done in Chabahar city (P = 0.018) and 4 years in the villages (P = 0.039). There was a higher level of recent P. vivax transmission compared to P. falciparum, based on the SCRs, in both the city and village settings. Serological analysis identified a decline in P. falciparum transmission in the urban areas of Chabahar, consistent with a previously described decrease in malaria in the early 1990s, demonstrating the utility of this approach to reconstruct exposure history. At present, it remains unclear whether the P. vivax antibody responses reflect active transmission due to new infections or relapse infections. The absence of parasitological and serological evidence of recent malaria transmission in Chabahar District is viable evidence for certification of

  15. Optimization of a multi-well colorimetric assay to determine haem species in Plasmodium falciparum in the presence of anti-malarials.

    PubMed

    Combrinck, Jill M; Fong, Kim Y; Gibhard, Liezl; Smith, Peter J; Wright, David W; Egan, Timothy J

    2015-06-24

    The activity of several well-known anti-malarials, including chloroquine (CQ), is attributed to their ability to inhibit the formation of haemozoin (Hz) in the malaria parasite. The formation of inert Hz, or malaria pigment, from toxic haem acquired from the host red blood cell of the parasite during haemoglobin digestion represents a pathway essential for parasite survival. Inhibition of this critical pathway therefore remains a desirable target for novel anti-malarials. A recent publication described the results of a haem fractionation assay used to directly determine haemoglobin, free haem and Hz in Plasmodium falciparum inoculated with CQ. CQ was shown to cause a dose-dependent increase in cellular-free haem that was correlated with decreased parasite survival. The method provided valuable information but was limited due to its low throughput and high demand on parasite starting material. Here, this haem fractionation assay has been successfully adapted to a higher throughput method in 24-well plates, significantly reducing lead times and starting material volumes. All major haem species in P. falciparum trophozoites, isolated through a series of cellular fractionation steps were determined spectrophotometrically in aqueous pyridine (5 % v/v, pH 7.5) as a low spin complex with haematin. Cell counts were determined using a haemocytometer and a rapid novel fluorescent flow cytometry method. A higher throughput haem fractionation assay in 24-well plates, containing at most ten million trophozoites was validated against the original published method using CQ and its robustness was confirmed. It provided a minimum six-fold improvement in productivity and 24-fold reduction in starting material volume. The assay was successfully applied to amodiaquine (AQ), which was shown to inhibit Hz formation, while the antifolate pyrimethamine (PYR) and the mitochondrial electron transporter inhibitor atovaquone (Atov) demonstrated no increase in toxic cellular free haem. This

  16. Differences in Fcgamma receptor IIa genotypes and IgG subclass pattern of anti-malarial antibodies between sympatric ethnic groups in Mali

    PubMed Central

    Israelsson, Elisabeth; Vafa, Manijeh; Maiga, Bakary; Lysén, Anna; Iriemenam, Nnaemeka C; Dolo, Amagana; Doumbo, Ogobara K; Troye-Blomberg, Marita; Berzins, Klavs

    2008-01-01

    Background The Ig Fc receptor family is an important link between the humoral and cellular immune systems. The association of a dimorphism in amino acid 131 (R/H) of the FcγRIIa with malaria severity, the R-allele being associated with a milder disease outcome, led to the investigation of the possible impact of this polymorphism in the interethnic difference in malaria susceptibility seen between the Fulani and Dogon in Mali. Methods Plasma from individuals from Mali (164 Fulani and 164 Dogon) were analysed for malaria-reactive and total IgG subclass antibodies using ELISA, and the same individuals were also genotyped for the FcγRIIa R131H polymorphism using RFLP-PCR. Statistical analyses of the IgG subclass levels were done by unpaired t-test and ANOVA, and genotype differences were tested by χ2-test. Results While the two ethnic groups showed a similar frequency of the FcγRIIa 131 R/H heterozygote genotype, 131R/R dominated over the 131 H/H genotype in the Dogon whereas the Fulani presented a similar frequency of the two homozygote genotypes. The two alleles were evenly distributed in the Fulani, while the Dogon were clearly biased towards the R-allele. The Fulani showed higher levels of anti-malarial IgG1, -2 and -3 antibodies, with a higher proportion of IgG2, than the Dogon. In the Fulani, H-allele carriers had higher anti-malarial IgG2 levels than R/R homozygotes, while in the Dogon, the R-allele carriers showed the higher IgG2 levels. For anti-malarial IgG3, the R-allele carriers in the Fulani had higher levels than the H/H homozygotes. Conclusion Taken together, the results showed marked interethnic differences in FcγRIIa R131H genotypes. Furthermore, the results indicate that the FcγRIIa R131H genotype may influence the IgG subclass responses related to protection against malaria, and that IgG2 may be of importance in this context. PMID:18793404

  17. Differences in Fcgamma receptor IIa genotypes and IgG subclass pattern of anti-malarial antibodies between sympatric ethnic groups in Mali.

    PubMed

    Israelsson, Elisabeth; Vafa, Manijeh; Maiga, Bakary; Lysén, Anna; Iriemenam, Nnaemeka C; Dolo, Amagana; Doumbo, Ogobara K; Troye-Blomberg, Marita; Berzins, Klavs

    2008-09-15

    The Ig Fc receptor family is an important link between the humoral and cellular immune systems. The association of a dimorphism in amino acid 131 (R/H) of the FcgammaRIIa with malaria severity, the R-allele being associated with a milder disease outcome, led to the investigation of the possible impact of this polymorphism in the interethnic difference in malaria susceptibility seen between the Fulani and Dogon in Mali. Plasma from individuals from Mali (164 Fulani and 164 Dogon) were analysed for malaria-reactive and total IgG subclass antibodies using ELISA, and the same individuals were also genotyped for the FcgammaRIIa R131H polymorphism using RFLP-PCR. Statistical analyses of the IgG subclass levels were done by unpaired t-test and ANOVA, and genotype differences were tested by chi2-test. While the two ethnic groups showed a similar frequency of the FcgammaRIIa 131 R/H heterozygote genotype, 131R/R dominated over the 131 H/H genotype in the Dogon whereas the Fulani presented a similar frequency of the two homozygote genotypes. The two alleles were evenly distributed in the Fulani, while the Dogon were clearly biased towards the R-allele. The Fulani showed higher levels of anti-malarial IgG1, -2 and -3 antibodies, with a higher proportion of IgG2, than the Dogon. In the Fulani, H-allele carriers had higher anti-malarial IgG2 levels than R/R homozygotes, while in the Dogon, the R-allele carriers showed the higher IgG2 levels. For anti-malarial IgG3, the R-allele carriers in the Fulani had higher levels than the H/H homozygotes. Taken together, the results showed marked interethnic differences in FcgammaRIIa R131H genotypes. Furthermore, the results indicate that the FcgammaRIIa R131H genotype may influence the IgG subclass responses related to protection against malaria, and that IgG2 may be of importance in this context.

  18. Ex vivo drug sensitivity profiles of Plasmodium falciparum field isolates from Cambodia and Thailand, 2005 to 2010, determined by a histidine-rich protein-2 assay

    PubMed Central

    2012-01-01

    Background In vitro drug susceptibility assay of Plasmodium falciparum field isolates processed “immediate ex vivo” (IEV), without culture adaption, and tested using histidine-rich protein-2 (HRP-2) detection as an assay, is an expedient way to track drug resistance. Methods From 2005 to 2010, a HRP-2 in vitro assay assessed 451 P. falciparum field isolates obtained from subjects with malaria in western and northern Cambodia, and eastern Thailand, processed IEV, for 50% inhibitory concentrations (IC50) against seven anti-malarial drugs, including artesunate (AS), dihydroartemisinin (DHA), and piperaquine. Results In western Cambodia, from 2006 to 2010, geometric mean (GM) IC50 values for chloroquine, mefloquine, quinine, AS, DHA, and lumefantrine increased. In northern Cambodia, from 2009–2010, GM IC50 values for most drugs approximated the highest western Cambodia GM IC50 values in 2009 or 2010. Conclusions Western Cambodia is associated with sustained reductions in anti-malarial drug susceptibility, including the artemisinins, with possible emergence, or spread, to northern Cambodia. This potential public health crisis supports continued in vitro drug IC50 monitoring of P. falciparum isolates at key locations in the region. PMID:22694953

  19. Antiplasmodial activity, in vivo pharmacokinetics and anti-malarial efficacy evaluation of hydroxypyridinone hybrids in a mouse model.

    PubMed

    Dambuza, Ntokozo S; Smith, Peter; Evans, Alicia; Norman, Jennifer; Taylor, Dale; Andayi, Andrew; Egan, Timothy; Chibale, Kelly; Wiesner, Lubbe

    2015-12-16

    During the erythrocytic stage in humans, malaria parasites digest haemoglobin of the host cell, and the toxic haem moiety crystallizes into haemozoin. Chloroquine acts by forming toxic complexes with haem molecules and interfering with their crystallization. In chloroquine-resistant strains, the drug is excluded from the site of action, which causes the parasites to accumulate less chloroquine in their acid food vacuoles than chloroquine-sensitive parasites. 3-Hydroxylpyridin-4-ones are known to chelate iron; hydroxypyridone-chloroquine (HPO-CQ) hybrids were synthesized in order to determine whether they can inhibit parasites proliferation in the parasitic digestive vacuole by withholding iron from plasmodial parasite metabolic pathway. Two HPO-CQ hybrids were tested against Plasmodium falciparum chloroquine-sensitive (D10 and 3D7) and -resistant strains (Dd2 and K1). The pharmacokinetic properties of active compounds were determined using a mouse model and blood samples were collected at different time intervals and analysed using LC-MS/MS. For in vivo efficacy the mice were infected with Plasmodium berghei in a 4-day Peters' test. The parasitaemia was determined from day 3 and the course of the infection was followed by microscopic examination of stained blood films every 2-3 days until a rise in parasitaemia was observed in all test subjects. IC50 values of the two compounds for sensitive and resistant strains were 0.064 and 0.047 µM (compound 1), 0.041 and 0.122 µM (compound 2) and 0.505 and 0.463 µM (compound 1), 0.089 and 0.076 µM (compound 2), respectively. Pharmacokinetic evaluation of these compounds showed low oral bioavailability and this affected in vivo efficacy when compounds were dosed orally. However, when dosed intravenously compound 1 showed a clearance rate of 28 ml/min/kg, an apparent volume of distribution of 20 l/kg and a half-life of 4.3 h. A reduction in parasitaemia was observed when compound 1 was dosed intravenously for four

  20. The challenge to avoid anti-malarial medicine stock-outs in an era of funding partners: the case of Tanzania

    PubMed Central

    2014-01-01

    Background Between 2007 and 2013, the Tanzanian public sector received 93.1 million doses of first-line anti-malarial artemisinin-based combination therapy (ACT) in the form of artemether-lumefantrine entirely supplied by funding partners. The introduction of a health facility ACT stock monitoring system using SMS technology by the National Malaria Control Programme in mid 2011 revealed a high frequency of stock-outs of ACT in primary care public health facilities. The objective of this study was to determine the pattern of availability of ACT and possible causes of observed stock-outs across public health facilities in Tanzania since mid-2011. Methods Data were collected weekly by the mobile phone reporting tool SMS for Life on ACT availability from over 5,000 public health facilities in Tanzania starting from September 2011 to December 2012. Stock data for all four age-dose levels of ACT across health facilities were summarized and supply of ACT at the national level was also documented. Results Over the period of 15 months, on average 29% of health facilities in Tanzania were completely stocked out of all four-age dose levels of the first-line anti-malarial with a median duration of total stock-out of six weeks. Patterns of total stock-out by region ranged from a low of 9% to a high of 52%. The ACT stock-outs were most likely caused by: a) insufficient ACT supplies entering Tanzania (e.g. in 2012 Tanzania received 10.9 million ACT doses compared with a forecast demand of 14.4 million doses); and b) irregular pattern of ACT supply (several months with no ACT stock). Conclusion The reduced ACT availability and irregular pattern of supply were due to cumbersome bureaucratic processes and delays both within the country and from the main donor, the Global Fund to Fight AIDS, Tuberculosis and Malaria. Tanzania should invest in strengthening both the supply system and the health information system using mHealth solutions such as SMS for Life. This will continue to

  1. The challenge to avoid anti-malarial medicine stock-outs in an era of funding partners: the case of Tanzania.

    PubMed

    Mikkelsen-Lopez, Inez; Shango, Winna; Barrington, Jim; Ziegler, Rene; Smith, Tom; deSavigny, Don

    2014-05-11

    Between 2007 and 2013, the Tanzanian public sector received 93.1 million doses of first-line anti-malarial artemisinin-based combination therapy (ACT) in the form of artemether-lumefantrine entirely supplied by funding partners. The introduction of a health facility ACT stock monitoring system using SMS technology by the National Malaria Control Programme in mid 2011 revealed a high frequency of stock-outs of ACT in primary care public health facilities. The objective of this study was to determine the pattern of availability of ACT and possible causes of observed stock-outs across public health facilities in Tanzania since mid-2011. Data were collected weekly by the mobile phone reporting tool SMS for Life on ACT availability from over 5,000 public health facilities in Tanzania starting from September 2011 to December 2012. Stock data for all four age-dose levels of ACT across health facilities were summarized and supply of ACT at the national level was also documented. Over the period of 15 months, on average 29% of health facilities in Tanzania were completely stocked out of all four-age dose levels of the first-line anti-malarial with a median duration of total stock-out of six weeks. Patterns of total stock-out by region ranged from a low of 9% to a high of 52%. The ACT stock-outs were most likely caused by: a) insufficient ACT supplies entering Tanzania (e.g. in 2012 Tanzania received 10.9 million ACT doses compared with a forecast demand of 14.4 million doses); and b) irregular pattern of ACT supply (several months with no ACT stock). The reduced ACT availability and irregular pattern of supply were due to cumbersome bureaucratic processes and delays both within the country and from the main donor, the Global Fund to Fight AIDS, Tuberculosis and Malaria. Tanzania should invest in strengthening both the supply system and the health information system using mHealth solutions such as SMS for Life. This will continue to assist in tracking ACT availability across

  2. Drugs use pattern for uncomplicated malaria in medicine retail outlets in Enugu urban, southeast Nigeria: implications for malaria treatment policy.

    PubMed

    Ezenduka, Charles C; Ogbonna, Brian O; Ekwunife, Obinna I; Okonta, Mathew J; Esimone, Charles O

    2014-06-24

    Malaria treatment policy recommends regular monitoring of drug utilization to generate information for ensuring effective use of anti-malarial drugs in Nigeria. This information is currently limited in the retail sector which constitutes a major source of malaria treatment in Nigeria, but are characterized by significant inappropriate use of drugs. This study analyzed the use pattern of anti-malarial drugs in medicine outlets to assess the current state of compliance to policy on the use of artemisinin-based combination therapy (ACT). A prospective cross-sectional survey of randomly selected medicine outlets in Enugu urban, southeast Nigeria, was conducted between May and August 2013, to determine the types, range, prices, and use pattern of anti-malarial drugs dispensed from pharmacies and patent medicine vendors (PMVs). Data were collected and analyzed for anti-malarial drugs dispensed for self-medication to patients, treatment by retail outlets and prescription from hospitals. A total of 1,321 anti-malarial drugs prescriptions were analyzed. ACT accounted for 72.7%, while monotherapy was 27.3%. Affordable Medicines Facility-malaria (AMFm) drugs contributed 33.9% (326/961) of ACT. Artemether-lumefantrine (AL), 668 (50.6%) was the most used anti-malarial drug, followed by monotherapy sulphadoxine-pyrimethamine (SP), 248 (18.8%). Median cost of ACT at $2.91 ($0.65-7.42) per dose, is about three times the median cost of monotherapy, $0.97 ($0.19-13.55). Total cost of medication (including co-medications) with ACT averaged $3.64 (95% CI; $3.53-3.75) per prescription, about twice the mean cost of treatment with monotherapy, $1.83 (95% CI; $1.57-2.1). Highest proportion 46.5% (614), of the anti-malarial drugs was dispensed to patients for self-treatment. Treatment by retail outlets accounted for 35.8% while 17.7% of the drugs were dispensed from hospital prescriptions. Self-medication, 82%, accounted for the highest source of monotherapy and a majority of prescriptions

  3. Drugs use pattern for uncomplicated malaria in medicine retail outlets in Enugu urban, southeast Nigeria: implications for malaria treatment policy

    PubMed Central

    2014-01-01

    Background Malaria treatment policy recommends regular monitoring of drug utilization to generate information for ensuring effective use of anti-malarial drugs in Nigeria. This information is currently limited in the retail sector which constitutes a major source of malaria treatment in Nigeria, but are characterized by significant inappropriate use of drugs. This study analyzed the use pattern of anti-malarial drugs in medicine outlets to assess the current state of compliance to policy on the use of artemisinin-based combination therapy (ACT). Methods A prospective cross-sectional survey of randomly selected medicine outlets in Enugu urban, southeast Nigeria, was conducted between May and August 2013, to determine the types, range, prices, and use pattern of anti-malarial drugs dispensed from pharmacies and patent medicine vendors (PMVs). Data were collected and analyzed for anti-malarial drugs dispensed for self-medication to patients, treatment by retail outlets and prescription from hospitals. Results A total of 1,321 anti-malarial drugs prescriptions were analyzed. ACT accounted for 72.7%, while monotherapy was 27.3%. Affordable Medicines Facility-malaria (AMFm) drugs contributed 33.9% (326/961) of ACT. Artemether-lumefantrine (AL), 668 (50.6%) was the most used anti-malarial drug, followed by monotherapy sulphadoxine-pyrimethamine (SP), 248 (18.8%). Median cost of ACT at $2.91 ($0.65-7.42) per dose, is about three times the median cost of monotherapy, $0.97 ($0.19-13.55). Total cost of medication (including co-medications) with ACT averaged $3.64 (95% CI; $3.53-3.75) per prescription, about twice the mean cost of treatment with monotherapy, $1.83 (95% CI; $1.57-2.1). Highest proportion 46.5% (614), of the anti-malarial drugs was dispensed to patients for self-treatment. Treatment by retail outlets accounted for 35.8% while 17.7% of the drugs were dispensed from hospital prescriptions. Self-medication, 82%, accounted for the highest source of monotherapy and

  4. A pre-PEXEL histidine-rich protein II erythrocyte binding peptide as a new way for anti-malarial vaccine development.

    PubMed

    Cifuentes, Gladys; Patarroyo, Manuel Elkin; Reyes, Claudia; Córtes, Jimena; Patarroyo, Manuel Alfonso

    2007-08-17

    The Plasmodium falciparum malaria parasite produces several proteins characterised by an unusually high histidine content in infected red blood cells (iRBC). The histidine-rich protein II (HRP-II) is synthesised throughout the parasite's asexual and gametocyte stages, transported through the parasitophorous vacuole (PV) to iRBC cytosol and membrane and released to the bloodstream via a PEXEL motif. Immunogenicity and protection-inducing studies were begun with an RBC high activity binding peptide (HABP) from this protein named 6800 (preceding the PEXEL motif) in the experimental Aotus monkey model. Modifying critical residues (determined by glycine scanning in this HABP) induced immunogenicity and protection against experimental challenge. Native 6800 did not bind to any HLA-DRbeta(1)(*) molecule, but these modified HABPs acquired the ability to specifically bind to HLA-DRbeta(1)(*)0701. (1)H NMR studies revealed that whilst 6800 had a random structure, modified immunogenic and protection-inducing 24230 displayed very short alpha-helical segments allowing appropriate binding to the MHCII-pep-TCR complex. Modifications in conserved HABPs preceding PEXEL motifs thus open up new avenues for subunit-based, multi-component synthetic anti-malarial vaccine development.

  5. 3D structure and immunogenicity of Plasmodium falciparum sporozoite induced associated protein peptides as components of fully-protective anti-malarial vaccine.

    PubMed

    Alba, Martha P; Almonacid, Hannia; Calderón, Dayana; Chacón, Edgar A; Poloche, Luis A; Patarroyo, Manuel A; Patarroyo, Manuel E

    2011-12-16

    SIAP-1 and SIAP-2 are proteins which are implicated in early events involving Plasmodium falciparum infection of the Anopheles mosquito vector and the human host. High affinity HeLa and HepG2 cell binding conserved peptides have been previously identified in these proteins, i.e. SIAP-1 34893 ((421)KVQGLSYLLRRKNGTKHPVY(440)) and SIAP-1 34899 ((541)YVLNSKLLNSRSFDKFKWIQ(560)) and SIAP-2 36879 ((181)LLLYSTNSEDNLDISFGELQ(200)). When amino acid sequences have been properly modified (replacements shown in bold) they have induced high antibody titres against sporozoites in Aotus monkeys (assessed by IFA) and in the corresponding recombinant proteins (determined by ELISA and Western blot). (1)H NMR studies of these conserved native and modified high activity binding peptides (HABPs) revealed that all had α-helical structures in different locations and lengths. Conserved and corresponding modified HABPs displayed different lengths between the residues fitting into MHCII molecule pockets 1-9 and different amino acid orientation based on their different HLA-DRβ1(∗) binding motifs and binding registers, suggesting that such modifications were associated with making them immunogenic. The results suggested that these modified HAPBs could be potential targets for inclusion as components of a fully-effective, minimal sub-unit based, multi-epitope, and multistage anti-malarial vaccine.

  6. Mining of miRNAs and potential targets from gene oriented clusters of transcripts sequences of the anti-malarial plant, Artemisia annua.

    PubMed

    Pérez-Quintero, Alvaro L; Sablok, Gaurav; Tatarinova, Tatiana V; Conesa, Ana; Kuo, Jimmy; López, Camilo

    2012-04-01

    miRNAs involved in the biosynthesis of artemisinin, an anti-malarial compound form the plant Artemisia annua, have been identified using computational approaches to find conserved pre-miRNAs in available A. annua UniGene collections. Eleven pre-miRNAs were found from nine families. Targets predicted for these miRNAs were mainly transcription factors for conserved miRNAs. No target genes involved in artemisinin biosynthesis were found. However, miR390 was predicted to target a gene involved in the trichome development, which is the site of synthesis of artemisinin and could be a candidate for genetic transformation aiming to increase the content of artemisinin. Phylogenetic analyses were carried out to determinate the relation between A. annua and other plant pre-miRNAs: the pre-miRNA-based phylogenetic trees failed to correspond to known phylogenies, suggesting that pre-miRNA primary sequences may be too variable to accurately predict phylogenetic relations.

  7. The anti-malarial artemisinin inhibits pro-inflammatory cytokines via the NF-κB canonical signaling pathway in PMA-induced THP-1 monocytes.

    PubMed

    Wang, Yue; Huang, Zhouqing; Wang, Liansheng; Meng, Shu; Fan, Yuqi; Chen, Ting; Cao, Jiatian; Jiang, Rujia; Wang, Changqian

    2011-02-01

    Several kinds of sesquiterpene lactones have been proven to inhibit NF-κB and to retard atherosclerosis by reducing lesion size and changing plaque composition. The anti-malarial artemisinin (Art) is a pure sesquiterpene lactone extracted from the Chinese herb Artemisia annua (qinghao, sweet wormwood). In the present study, we demonstrate that artemisinin inhibits the secretion and the mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 in a dose-dependent manner in phorbol 12-myristate 13-acetate (PMA)-induced THP-1 human monocytes. We also found that the NF-κB specific inhibitor, Bay 11-7082, inhibited the expression of these pro-inflammatory cytokines, suggesting that the NF-κB pathway may be involved in the decreased cytokine release. At all time-points (1-6 h), artemisinin impeded the phosphorylation of IKKα/ß, the phosphorylation and degradation of IκBα and the nuclear translocation of the NF-κB p65 subunit. Additionally, artemisinin inhibited the translocation of the NF-κB p65 subunit as demonstrated by confocal laser scanning microscopic analysis and by NF-κB binding assays. Our data indicate that artemisinin exerts an anti-inflammatory effect on PMA-induced THP-1 monocytes, suggesting the potential role of artemisinin in preventing the inflammatory progression of atherosclerosis.

  8. Effect of external stress on density and size of glandular trichomes in full-grown Artemisia annua, the source of anti-malarial artemisinin

    PubMed Central

    Kjær, Anders; Grevsen, Kai; Jensen, Martin

    2012-01-01

    Background and aims Glandular trichomes (GT) of Artemisia annua produce valuable compounds for pharmaceutical and industrial uses, most notably the anti-malarial artemisinin. Our aim was to find out whether the density, number and size of GT can be manipulated to advantage by environmental stress. A range of external stress treatments, including stress response regulators, was therefore given to fully grown plants under field and greenhouse conditions. Methodology In a field experiment (Ex1), seed-grown plants were subjected to chemical or physical stress and plants analysed after 5 weeks. In a greenhouse experiment (Ex2), three groups of clonally derived plants were stressed at weekly intervals for 5 weeks. Stress treatments included sandblasting, leaf cutting and spraying with jasmonic acid, salicylic acid, chitosan oligosaccharide (COS), H2O2 (HP) and NaCl (SC)at different concentrations. Leaves from an upper and a lower position on the plants were analysed by fluorescence microscopy to determine the density and size of GT. Principal results Densities of GT on upper leaves of full-grown A. annua plants generally showed no response to external stress and only plants from one clone of Ex2 supported the hypothesis that increased density of GT was inducible in upper leaves by stress (significant for SC, HP and COS). The density of GT on lower leaves was not affected by stress in any experiment. Glandular trichomes were significantly smaller on the lower leaves in response to stress in Ex2, and a similar non-significant trend was observed in Ex1. Conclusions The results indicate a dynamic system in which stress treatments of large A. annua plants had a minor promoting effect on the initiation of GT in developing leaves, and a maturing effect of GT later in the lifetime of the individual GT. The hypothesis that applying stress can induce larger GT or more numerous GT was rejected. PMID:22833781

  9. Use of a colorimetric (DELI) test for the evaluation of chemoresistance of Plasmodium falciparum and Plasmodium vivax to commonly used anti-plasmodial drugs in the Brazilian Amazon

    PubMed Central

    2013-01-01

    Background The emergence and spread of Plasmodium falciparum and Plasmodium vivax resistance to available anti-malarial drugs represents a major drawback in the control of malaria and its associated morbidity and mortality. The aim of this study was to evaluate the chemoresistance profile of P. falciparum and P. vivax to commonly used anti-plasmodial drugs in a malaria-endemic area in the Brazilian Amazon. Methods The study was carried out in Manaus (Amazonas state), in the Brazilian Amazon. A total of 88 P. falciparum and 178 P. vivax isolates was collected from 2004 to 2007. The sensitivity of P. falciparum isolates was determined to chloroquine, quinine, mefloquine and artesunate and the sensitivity of P. vivax isolates was determined to chloroquine and mefloquine, by using the colorimetric DELI test. Results As expected, a high prevalence of P. falciparum isolates resistant to chloroquine (78.1%) was observed. The prevalence of isolates with profile of resistance or decreased sensitivity for quinine, mefloquine and artesunate was 12.7, 21.2 and 11.7%, respectively. In the case of P. vivax, the prevalence of isolates with profile of resistance for chloroquine and mefloquine was 9.8 and 28%, respectively. No differences in the frequencies of isolates with profile of resistance or geometric mean IC50s were seen when comparing the data obtained in 2004, 2005, 2006 and 2007, for all tested anti-malarials. Conclusions The great majority of P. falciparum isolates in the Brazilian malaria-endemic area remain resistant to chloroquine, and the decreased sensitivity to quinine, mefloquine and artesunate observed in 10–20% of the isolates must be taken with concern, especially for artesunate. Plasmodium vivax isolates also showed a significant proportion of isolates with decreased sensitivity to chloroquine (first-line drug) and mainly to mefloquine. The data presented here also confirm the usefulness of the DELI test to generate results able to impact on public health

  10. Communicating the AMFm message: exploring the effect of communication and training interventions on private for-profit provider awareness and knowledge related to a multi-country anti-malarial subsidy intervention

    PubMed Central

    2014-01-01

    Background The Affordable Medicines Facility - malaria (AMFm), implemented at national scale in eight African countries or territories, subsidized quality-assured artemisinin combination therapy (ACT) and included communication campaigns to support implementation and promote appropriate anti-malarial use. This paper reports private for-profit provider awareness of key features of the AMFm programme, and changes in provider knowledge of appropriate malaria treatment. Methods This study had a non-experimental design based on nationally representative surveys of outlets stocking anti-malarials before (2009/10) and after (2011) the AMFm roll-out. Results Based on data from over 19,500 outlets, results show that in four of eight settings, where communication campaigns were implemented for 5–9 months, 76%-94% awareness of the AMFm ‘green leaf’ logo, 57%-74% awareness of the ACT subsidy programme, and 52%-80% awareness of the correct recommended retail price (RRP) of subsidized ACT were recorded. However, in the remaining four settings where communication campaigns were implemented for three months or less, levels were substantially lower. In six of eight settings, increases of at least 10 percentage points in private for-profit providers’ knowledge of the correct first-line treatment for uncomplicated malaria were seen; and in three of these the levels of knowledge achieved at endline were over 80%. Conclusions The results support the interpretation that, in addition to the availability of subsidized ACT, the intensity of communication campaigns may have contributed to the reported levels of AMFm-related awareness and knowledge among private for-profit providers. Future subsidy programmes for anti-malarials or other treatments should similarly include communication activities. PMID:24495691

  11. Trends in malaria cases, hospital admissions and deaths following scale-up of anti-malarial interventions, 2000–2010, Rwanda

    PubMed Central

    2012-01-01

    groups either increased or remained unchanged. Rainfall and temperature remained favourable for malaria transmission. The annual all-cause mortality in children under-five in household surveys declined from 152 per 1,000 live births during 2001–2005, to 76 per 1,000 live births in 2006–2010 (55% decline). The five-year cumulative number of all-cause deaths in hospital declined 28% (8,051 to 5,801) during the same period. Conclusions A greater than 50% decline in confirmed malaria cases, admissions and deaths at district hospitals in Rwanda since 2005 followed a marked increase in ITN coverage and use of ACT. The decline occurred among both children under-five and in those five years and above, while hospital utilization increased and suitable conditions for malaria transmission persisted. Declines in malaria indicators in children under 5 years were more striking than in the older age groups. The resurgence in cases associated with decreased ITN coverage in 2009 highlights the need for sustained high levels of anti-malarial interventions in Rwanda and other malaria endemic countries. PMID:22823945

  12. Light-sensitive intelligent drug delivery systems.

    PubMed

    Alvarez-Lorenzo, Carmen; Bromberg, Lev; Concheiro, Angel

    2009-01-01

    Drug delivery systems (DDS) capable of releasing an active molecule at the appropriate site and at a rate that adjusts in response to the progression of the disease or to certain functions/biorhythms of the organism are particularly appealing. Biocompatible materials sensitive to certain physiological variables or external physicochemical stimuli (intelligent materials) can be used for achieving this aim. Light-responsiveness is receiving increasing attention owing to the possibility of developing materials sensitive to innocuous electromagnetic radiation (mainly in the UV, visible and near-infrared range), which can be applied on demand at well delimited sites of the body. Some light-responsive DDS are of a single use (i.e. the light triggers an irreversible structural change that provokes the delivery of the entire dose) while others able to undergo reversible structural changes when cycles of light/dark are applied, behave as multi-switchable carriers (releasing the drug in a pulsatile manner). In this review, the mechanisms used to develop polymeric micelles, gels, liposomes and nanocomposites with light-sensitiveness are analyzed. Examples of the capability of some polymeric, lipidic and inorganic structures to regulate the release of small solutes and biomacromolecules are presented and the potential of light-sensitive carriers as functional components of intelligent DDS is discussed.

  13. Characterization of two malaria parasite organelle translation elongation factor G proteins: the likely targets of the anti-malarial fusidic acid.

    PubMed

    Johnson, Russell A; McFadden, Geoffrey I; Goodman, Christopher D

    2011-01-01

    Malaria parasites harbour two organelles with bacteria-like metabolic processes that are the targets of many anti-bacterial drugs. One such drug is fusidic acid, which inhibits the translation component elongation factor G. The response of P. falciparum to fusidic acid was characterised using extended SYBR-Green based drug trials. This revealed that fusidic acid kills in vitro cultured P. falciparum parasites by immediately blocking parasite development. Two bacterial-type protein translation elongation factor G genes are identified as likely targets of fusidic acid. Sequence analysis suggests that these proteins function in the mitochondria and apicoplast and both should be sensitive to fusidic acid. Microscopic examination of protein-reporter fusions confirm the prediction that one elongation factor G is a component of parasite mitochondria whereas the second is a component of the relict plastid or apicoplast. The presence of two putative targets for a single inhibitory compound emphasizes the potential of elongation factor G as a drug target in malaria.

  14. Evaluation of the QT effect of a combination of piperaquine and a novel anti-malarial drug candidate OZ439, for the treatment of uncomplicated malaria

    PubMed Central

    Darpo, Borje; Ferber, Georg; Siegl, Peter; Laurijssens, Bart; Macintyre, Fiona; Toovey, Stephen; Duparc, Stephan

    2015-01-01

    Aims The aim was to investigate the QT effect of a single dose combination regimen of piperaquine phosphate (PQP) and a novel aromatic trioxolane, OZ439, for malaria treatment. Methods Exposure–response (ER) analysis was performed on data from a placebo-controlled, single dose, study with OZ439 and PQP. Fifty-nine healthy subjects aged 18 to 55 years received OZ439 alone or placebo in a first period, followed by OZ439 plus PQP or matching placebos in period 2. OZ439 and PQP doses ranged from 100–800 mg and 160–1440 mg, respectively. Twelve-lead ECG tracings and PK samples were collected serially pre- and post-dosing. Results A significant relation between plasma concentrations and placebo-corrected change from baseline QTcF (ΔΔQTcF) was demonstrated for piperaquine, but not for OZ439, with a mean slope of 0.047 ms per ng ml−1 (90% CI 0.038, 0.057). Using an ER model that accounts for plasma concentrations of both piperaquine and OZ439, a largest mean QTcF effect of 14 ms (90% CI 10, 18 ms) and 18 ms (90% CI 14, 22 ms) was predicted at expected plasma concentrations of a single dose 800 mg OZ439 combined with PQP 960 mg (188 ng ml−1) and 1440 mg (281 ng ml−1), respectively, administered in the fasted state. Conclusions Piperaquine prolongs the QTc interval in a concentration-dependent way. A single dose regimen combining 800 mg OZ439 with 960 mg or 1440 mg PQP is expected to result in lower peak piperaquine plasma concentrations compared with available 3 day PQP-artemisinin combinations and can therefore be predicted to cause less QTc prolongation. PMID:25966781

  15. Integrating heterogeneous drug sensitivity data from cancer pharmacogenomic studies

    PubMed Central

    Pozdeyev, Nikita; Yoo, Minjae; Mackie, Ryan; Schweppe, Rebecca E.; Tan, Aik Choon; Haugen, Bryan R.

    2016-01-01

    The consistency of in vitro drug sensitivity data is of key importance for cancer pharmacogenomics. Previous attempts to correlate drug sensitivities from the large pharmacogenomics databases, such as the Cancer Cell Line Encyclopedia (CCLE) and the Genomics of Drug Sensitivity in Cancer (GDSC), have produced discordant results. We developed a new drug sensitivity metric, the area under the dose response curve adjusted for the range of tested drug concentrations, which allows integration of heterogeneous drug sensitivity data from the CCLE, the GDSC, and the Cancer Therapeutics Response Portal (CTRP). We show that there is moderate to good agreement of drug sensitivity data for many targeted therapies, particularly kinase inhibitors. The results of this largest cancer cell line drug sensitivity data analysis to date are accessible through the online portal, which serves as a platform for high power pharmacogenomics analysis. PMID:27322211

  16. Direct comparison of the histidine-rich protein-2 enzyme-linked immunosorbent assay (HRP-2 ELISA) and malaria SYBR green I fluorescence (MSF) drug sensitivity tests in Plasmodium falciparum reference clones and fresh ex vivo field isolates from Cambodia

    PubMed Central

    2013-01-01

    Background Performance of the histidine-rich protein-2 enzyme-linked immunosorbent assay (HRP-2 ELISA) and malaria SYBR Green I fluorescence (MSF) drug sensitivity tests were directly compared using Plasmodium falciparum reference strains and fresh ex vivo isolates from Cambodia against a panel of standard anti-malarials. The objective was to determine which of these two common assays is more appropriate for studying drug susceptibility of “immediate ex vivo” (IEV) isolates, analysed without culture adaption, in a region of relatively low malaria transmission. Methods Using the HRP-2 and MSF methods, the 50% inhibitory concentration (IC50) values against a panel of malaria drugs were determined for P. falciparum reference clones (W2, D6, 3D7 and K1) and 41 IEV clinical isolates from an area of multidrug resistance in Cambodia. Comparison of the IC50 values from the two methods was made using Wilcoxon matched pair tests and Pearson’s correlation. The lower limit of parasitaemia detection for both methods was determined for reference clones and IEV isolates. Since human white blood cell (WBC) DNA in clinical samples is known to reduce MSF assay sensitivity, SYBR Green I fluorescence linearity of P. falciparum samples spiked with WBCs was evaluated to assess the relative degree to which MSF sensitivity is reduced in clinical samples. Results IC50 values correlated well between the HRP-2 and MSF methods when testing either P. falciparum reference clones or IEV isolates against 4-aminoquinolines (chloroquine, piperaquine and quinine) and the quinoline methanol mefloquine (Pearson r = 0.85-0.99 for reference clones and 0.56-0.84 for IEV isolates), whereas a weaker IC50 value correlation between methods was noted when testing artemisinins against reference clones and lack of correlation when testing IEV isolates. The HRP-2 ELISA produced a higher overall success rate (90% for producing IC50 best-fit sigmoidal curves), relative to only a 40% success rate for the

  17. Crystallization, X-Ray Structure Determination and Structure-Based Drug Design for Targeted Malarial Enzymes

    DTIC Science & Technology

    1998-07-01

    COOPERATIVE AGREEMENT NUMBER DAMD17-95-2-5007 TITLE: Crystallization, X-ray Structure Determination and Structure-Based Drug Design for...approach for the develpment of anti-malarial agent using structure-based drug design . This technique will enable us to identify active site inhibitors...based drug design project high resolution three domensional structure of the enzyme - inhibitor complex provides the basis for further modifications

  18. Using Click Chemistry to Identify Potential Drug Targets in Plasmodium

    DTIC Science & Technology

    2015-04-01

    mammalian cycle. Inhibiting this step can block malaria at an early step. However, few anti-malar ials target l iver infection by sporozo ites. Our...step of the Plasmodium mammalian cycle. Inhibiting this step can block malaria at an early step. However, few anti-malarials target liver infection...intrahepatic development 2. Keywords Plasmodium, sporozoites, liver infection, kinase, drugs, malaria 3. Accomplishments • What were the major

  19. Analysis of Fcgamma receptor IIa (cd32) gene polymorphism and anti-malarial IgG subclass antibodies to asexual blood-stage antigen of Plasmodium falciparum in an unstable malaria endemic area of Iran.

    PubMed

    Zakeri, Sedigheh; Mashhadi, Rahil; Mehrizi, Akram Abouie; Djadid, Navid Dinparast

    2013-05-01

    One of the main host genetic factors involved in inflammation, immune responses and pathogenesis of malaria is FcγRIIa (cd32) gene. A single point mutation at position 131 replace an arginine (R) with a histidine (H) that can affect the affinity of the receptor for human IgG subclasses. This investigation was designed to explore the polymorphisms at FcγRIIa gene in association with both anti-malarial total IgG antibody and IgG subclass profiles to C-terminal region of Plasmodium falciparum merozoite surface protein 1 (PfMSP-1(19)). In this study, 166 infected patients with P. falciparum who are living in a malaria endemic area of Iran were studied using PCR-RFLP and ELISA methods. The results showed that the frequency of FcγRIIa-R/R131, -R/H131 and -H/H131 genotypes was 9.6%, 42.8% and 47.6%, respectively. Level of total IgG to recombinant PfMSP-1(19) antigen showed that there was no difference among the FcγRIIa-R/R131, -R/H131 and -H/H131 groups. With regards to the IgG subclasses, the anti-malarial IgG1 antibodies predominated. Also, there was a significant difference between the frequency of positive responders for anti-PfMSP-1(19) IgG and IgG1 antibodies in P. falciparum-infected individuals with FcγRIIa-R/R131, -R/H131 or -H/H131 genotypes (P<0.05, X(2) test). Regarding to IgG2-PfMSP-1(19) antibody, 27.27% (FcγRIIa-R/R131), 25.71% (FcγRIIa-R/H131) and 22.2% (FcγRIIa-H/H131) of IgG responders showed positive antibody response. Taken together, this study is the first report that exhibits the high frequency of both FcγRIIa-H131H genotypes and H131 allele in the Baluchi ethnic group, which was similar to the Fulani ethnic group. The present results provide additional data to understand the role of FcγRIIa-131 genotypes in the pathogenesis of malaria.

  20. An Integrated Approach to Anti-Cancer Drug Sensitivity Prediction.

    PubMed

    Berlow, Noah; Haider, Saad; Wan, Qian; Geltzeiler, Mathew; Davis, Lara E; Keller, Charles; Pal, Ranadip

    2014-01-01

    A framework for design of personalized cancer therapy requires the ability to predict the sensitivity of a tumor to anticancer drugs. The predictive modeling of tumor sensitivity to anti-cancer drugs has primarily focused on generating functions that map gene expressions and genetic mutation profiles to drug sensitivity. In this paper, we present a new approach for drug sensitivity prediction and combination therapy design based on integrated functional and genomic characterizations. The modeling approach when applied to data from the Cancer Cell Line Encyclopedia shows a significant gain in prediction accuracy as compared to elastic net and random forest techniques based on genomic characterizations. Utilizing a Mouse Embryonal Rhabdomyosarcoma cell culture and a drug screen of 60 targeted drugs, we show that predictive modeling based on functional data alone can also produce high accuracy predictions. The framework also allows us to generate personalized tumor proliferation circuits to gain further insights on the individualized biological pathway.

  1. Sensitive radioenzymatic assay for catechol drugs

    SciTech Connect

    Durrett, L.R.; Ziegler, M.G.

    1980-01-01

    This assay measures picogram quantities of catechol drugs and endogenous catecholamines in body tissues and fluids. The catechols are converted to their 3H-O-methyl metabolites during incubation with 3H-S-adenosylmethionine then separated by solvent extraction and thin-layer chromatography. Most drugs containing the catechol structure can be radiolabeled and separated from norepinephrine and epinephrine by this technique to provide simultaneous measurement of endogenous and exogenously administered catechols. The disposition of isoproterenol in tissues and fluids of man and experimental animals is measured to illustrate the utility of this assay. The reactivity of several commonly administered catechol drugs with COMT is described and the possible implications discussed.

  2. Conditioned and sensitized responses to stimulant drugs in humans.

    PubMed

    Leyton, Marco

    2007-11-15

    In animal models considerable evidence suggests that increased motivation to seek and ingest drugs of abuse are related to conditioned and sensitized activations of the mesolimbic dopamine (DA) system. Direct evidence for these phenomena in humans, though, is sparse. However, recent studies support the following. First, the acute administration of drugs of abuse across pharmacological classes increases extracellular DA levels within the human ventral striatum. Second, individual differences in the magnitude of this response correlate with rewarding effects of the drugs and the personality trait of novelty seeking. Third, transiently diminishing DA transmission in humans decreases drug craving, the propensity to preferentially respond to reward-paired stimuli, and the ability to sustain responding for future drug reward. Finally, very recent studies suggest that repeated exposure to stimulant drugs, either on the street or in the laboratory, can lead to conditioned and sensitized behavioral responses and DA release. In contrast to these findings, though, in individuals with a long history of substance abuse, drug-induced DA release is decreased. This diminished DA release could reflect two different phenomena. First, it is possible that drug withdrawal related decrements in DA cell function persist longer than previously suspected. Second, drug-paired stimuli may gain marked conditioned control over the release of DA and the expression of sensitization leading to reduced DA release when drug-related cues are absent. Based on these observations a two-factor hypothesis of the role of DA in drug abuse is proposed. In the presence of drug cues, conditioned and sensitized DA release would occur leading to focused drug-seeking behavior. In comparison, in the absence of drug-related stimuli DA function would be reduced, diminishing the ability of individuals to sustain goal-directed behavior and long-term objectives. This conditioned control of the expression of sensitized

  3. A pharmacogenomic method for individualized prediction of drug sensitivity

    PubMed Central

    Cohen, Adam L; Soldi, Raffaella; Zhang, Haiyu; Gustafson, Adam M; Wilcox, Ryan; Welm, Bryan E; Chang, Jeffrey T; Johnson, Evan; Spira, Avrum; Jeffrey, Stefanie S; Bild, Andrea H

    2011-01-01

    Identifying the best drug for each cancer patient requires an efficient individualized strategy. We present MATCH (Merging genomic and pharmacologic Analyses for Therapy CHoice), an approach using public genomic resources and drug testing of fresh tumor samples to link drugs to patients. Valproic acid (VPA) is highlighted as a proof-of-principle. In order to predict specific tumor types with high probability of drug sensitivity, we create drug response signatures using publically available gene expression data and assess sensitivity in a data set of >40 cancer types. Next, we evaluate drug sensitivity in matched tumor and normal tissue and exclude cancer types that are no more sensitive than normal tissue. From these analyses, breast tumors are predicted to be sensitive to VPA. A meta-analysis across breast cancer data sets shows that aggressive subtypes are most likely to be sensitive to VPA, but all subtypes have sensitive tumors. MATCH predictions correlate significantly with growth inhibition in cancer cell lines and three-dimensional cultures of fresh tumor samples. MATCH accurately predicts reduction in tumor growth rate following VPA treatment in patient tumor xenografts. MATCH uses genomic analysis with in vitro testing of patient tumors to select optimal drug regimens before clinical trial initiation. PMID:21772261

  4. Drug Wanting: Behavioral Sensitization and Relapse to Drug-Seeking Behavior

    PubMed Central

    Kalivas, Peter W.

    2011-01-01

    Repeated exposure to drugs of abuse enhances the motor-stimulant response to these drugs, a phenomenon termed behavioral sensitization. Animals that are extinguished from self-administration training readily relapse to drug, conditioned cue, or stress priming. The involvement of sensitization in reinstated drug-seeking behavior remains controversial. This review describes sensitization and reinstated drug seeking as behavioral events, and the neural circuitry, neurochemistry, and neuropharmacology underlying both behavioral models will be described, compared, and contrasted. It seems that although sensitization and reinstatement involve overlapping circuitry and neurotransmitter and receptor systems, the role of sensitization in reinstatement remains ill-defined. Nevertheless, it is argued that sensitization remains a useful model for determining the neural basis of addiction, and an example is provided in which data from sensitization studies led to potential pharmacotherapies that have been tested in animal models of relapse and in human addicts. PMID:21490129

  5. Visual contrast sensitivity in drug-induced Parkinsonism.

    PubMed

    Bulens, C; Meerwaldt, J D; van der Wildt, G J; Keemink, C J

    1989-03-01

    The influence of stimulus orientation on contrast sensitivity function was studied in 10 patients with drug-induced Parkinsonism. Nine of the 10 patients had at least one eye with contrast sensitivity deficit for vertical and/or horizontal stimuli. Only generalised contrast sensitivity loss, observed in two eyes, was stimulus orientation independent. All spatial frequency-selective contrast deficits in 15 eyes were orientation dependent. The striking similarity between the pattern of contrast sensitivity loss in drug-induced Parkinsonism and that in idiopathic Parkinson's disease, suggests that generalised dopaminergic deficiency, from whatever cause, affects visual function in an analogous way.

  6. Visual contrast sensitivity in drug-induced Parkinsonism.

    PubMed Central

    Bulens, C; Meerwaldt, J D; van der Wildt, G J; Keemink, C J

    1989-01-01

    The influence of stimulus orientation on contrast sensitivity function was studied in 10 patients with drug-induced Parkinsonism. Nine of the 10 patients had at least one eye with contrast sensitivity deficit for vertical and/or horizontal stimuli. Only generalised contrast sensitivity loss, observed in two eyes, was stimulus orientation independent. All spatial frequency-selective contrast deficits in 15 eyes were orientation dependent. The striking similarity between the pattern of contrast sensitivity loss in drug-induced Parkinsonism and that in idiopathic Parkinson's disease, suggests that generalised dopaminergic deficiency, from whatever cause, affects visual function in an analogous way. PMID:2926418

  7. Cytostatic versus cytocidal profiling of quinoline drug combinations via modified fixed-ratio isobologram analysis.

    PubMed

    Gorka, Alexander P; Jacobs, Lauren M; Roepe, Paul D

    2013-09-18

    Drug combination therapy is the frontline of malaria treatment. There is an ever-accelerating need for new, efficacious combination therapies active against drug resistant malaria. Proven drugs already in the treatment pipeline, such as the quinolines, are important components of current combination therapy and also present an attractive test bank for rapid development of new concepts. The efficacy of several drug combinations versus chloroquine-sensitive and chloroquine-resistant strains was measured using both cytostatic and cytocidal potency assays. These screens identify quinoline and non-quinoline pairs that exhibit synergy, additivity, or antagonism using the fixed-ratio isobologram method and find tafenoquine - methylene blue combination to be the most synergistic. Also, interestingly, for selected pairs, additivity, synergy, or antagonism defined by quantifying IC50 (cytostatic potency) does not necessarily predict similar behaviour when potency is defined by LD50 (cytocidal potency). These data further support an evolving new model for quinoline anti-malarials, wherein haem and haemozoin are the principle target for cytostatic activity, but may not be the only target relevant for cytocidal activity.

  8. Gene sensitizes cancer cells to chemotherapy drugs

    Cancer.gov

    NCI scientists have found that a gene, Schlafen-11 (SLFN11), sensitizes cells to substances known to cause irreparable damage to DNA.  As part of their study, the researchers used a repository of 60 cell types to identify predictors of cancer cell respons

  9. Population genetics and drug resistance markers: an essential for malaria surveillance in Pakistan.

    PubMed

    Raza, Afsheen; Beg, Mohammad Asim

    2013-12-01

    Plasmodium (P.) vivax is the prevalent malarial species accounting for 70% of malaria cases in Pakistan. However, baseline epidemiological data on P. vivax population structure and drug resistance are lacking from Pakistan. For population structure studies, molecular genetic markers, circumsporozoite protein (csp) and merozoite surface protein-1 (msp-1) are considered useful as these play an important role in P. vivax survival under immune and environmental pressure. Furthermore, these genes have also been identified as suitable candidates for vaccine development. While efforts for effective vaccine are underway, anti-malarial agents remain the mainstay for control. Evidence of resistance against commonly used anti-malarial agents, particularly Sulphadoxine-Pyrimethamine (SP) is threatening to make this form of control defunct. Therefore, studies on drug resistance are necessary so that anti-malarial treatment strategies can be structured and implemented accordingly by the Malaria Control Program, Pakistan. This review aims to provide information on genetic markers of P. vivax population structure and drug resistance and comment on their usefulness in molecular surveillance and control.

  10. Methods to Increase the Sensitivity of High Resolution Melting Single Nucleotide Polymorphism Genotyping in Malaria.

    PubMed

    Daniels, Rachel; Hamilton, Elizabeth J; Durfee, Katelyn; Ndiaye, Daouda; Wirth, Dyann F; Hartl, Daniel L; Volkman, Sarah K

    2015-11-10

    Despite decades of eradication efforts, malaria remains a global burden. Recent renewed interest in regional elimination and global eradication has been accompanied by increased genomic information about Plasmodium parasite species responsible for malaria, including characteristics of geographical populations as well as variations associated with reduced susceptibility to anti-malarial drugs. One common genetic variation, single-nucleotide polymorphisms (SNPs), offers attractive targets for parasite genotyping. These markers are useful not only for tracking drug resistance markers but also for tracking parasite populations using markers not under drug or other selective pressures. SNP genotyping methods offer the ability to track drug resistance as well as to fingerprint individual parasites for population surveillance, particularly in response to malaria control efforts in regions nearing elimination status. While informative SNPs have been identified that are agnostic to specific genotyping technologies, high-resolution melting (HRM) analysis is particularly suited to field-based studies. Compared to standard fluorescent-probe based methods that require individual SNPs in a single labeled probe and offer at best 10% sensitivity to detect SNPs in samples that contain multiple genomes (polygenomic), HRM offers 2-5% sensitivity. Modifications to HRM, such as blocked probes and asymmetric primer concentrations as well as optimization of amplification annealing temperatures to bias PCR towards amplification of the minor allele, further increase the sensitivity of HRM. While the sensitivity improvement depends on the specific assay, we have increased detection sensitivities to less than 1% of the minor allele. In regions approaching malaria eradication, early detection of emerging or imported drug resistance is essential for prompt response. Similarly, the ability to detect polygenomic infections and differentiate imported parasite types from cryptic local reservoirs

  11. Transport of isometamidium (Samorin) by drug-resistant and drug-sensitive Trypanosoma congolense.

    PubMed

    Sutherland, I A; Mounsey, A; Holmes, P H

    1992-06-01

    The uptake kinetics of a 14C-labelled trypanocidal compound isometamidium chloride (Samorin, RMB Animal Health Ltd, UK) was measured in drug-resistant and drug-sensitive Trypanosoma congolense. It was established that drug uptake was significantly more rapid and quantitatively greater in drug-sensitive parasites. There was clear evidence that drug uptake in both the resistant and sensitive trypanosomes was by a specific, receptor-mediated process. This specific drug transport was energy-dependent, being sensitive to metabolic inhibition with SHAM/glycerol. Significant differences in drug transport were observed which could be correlated with resistance to isometamidium. The optimal pH for drug accumulation was lowered in the resistant trypanosomes; this finding, along with an observed change in specificity for the related compound homidium bromide, suggested that the specific receptor for isometamidium is altered in the resistant trypanosomes, possibly resulting in a reduction in drug uptake. In addition to these alterations in drug uptake, efflux of isometamidium also appears to occur in the resistant trypanosomes. Both a reduction in incubation temperature and metabolic inhibition increased the level of trypanosome-associated isometamidium in the resistant parasites. This was in contrast to observations using drug-sensitive parasites. Furthermore, the addition of calcium flux-modulating agents to the incubation medium also resulted in an increase in accumulation by the resistant parasites.

  12. High resolution melting: a useful field-deployable method to measure dhfr and dhps drug resistance in both highly and lowly endemic Plasmodium populations.

    PubMed

    Ndiaye, Yaye Dié; Diédhiou, Cyrille K; Bei, Amy K; Dieye, Baba; Mbaye, Aminata; Mze, Nasserdine Papa; Daniels, Rachel F; Ndiaye, Ibrahima M; Déme, Awa B; Gaye, Amy; Sy, Mouhamad; Ndiaye, Tolla; Badiane, Aida S; Ndiaye, Mouhamadou; Premji, Zul; Wirth, Dyann F; Mboup, Souleymane; Krogstad, Donald; Volkman, Sarah K; Ahouidi, Ambroise D; Ndiaye, Daouda

    2017-04-19

    Emergence and spread of drug resistance to every anti-malarial used to date, creates an urgent need for development of sensitive, specific and field-deployable molecular tools for detection and surveillance of validated drug resistance markers. Such tools would allow early detection of mutations in resistance loci. The aim of this study was to compare common population signatures and drug resistance marker frequencies between two populations with different levels of malaria endemicity and history of anti-malarial drug use: Tanzania and Sénégal. This was accomplished by implementing a high resolution melting assay to study molecular markers of drug resistance as compared to polymerase chain reaction-restriction fragment length polymorphism (PCR/RFLP) methodology. Fifty blood samples were collected each from a lowly malaria endemic site (Sénégal), and a highly malaria endemic site (Tanzania) from patients presenting with uncomplicated Plasmodium falciparum malaria at clinic. Data representing the DHFR were derived using both PCR-RFLP and HRM assay; while genotyping data representing the DHPS were evaluated in Senegal and Tanzania using HRM. Msp genotyping analysis was used to characterize the multiplicity of infection in both countries. A high prevalence of samples harbouring mutant DHFR alleles was observed in both population using both genotyping techniques. HRM was better able to detect mixed alleles compared to PCR/RFLP for DHFR codon 51 in Tanzania; and only HRM was able to detect mixed infections from Senegal. A high prevalence of mutant alleles in DHFR (codons 51, 59, 108) and DHPS (codon 437) were found among samples from Sénégal while no mutations were observed at DHPS codons 540 and 581, from both countries. Overall, the frequency of samples harbouring either a single DHFR mutation (S108N) or double mutation in DHFR (C59R/S108N) was greater in Sénégal compared to Tanzania. Here the results demonstrate that HRM is a rapid, sensitive, and field

  13. Multifunctional, stimuli-sensitive nanoparticulate systems for drug delivery

    PubMed Central

    Torchilin, Vladimir P.

    2015-01-01

    The use of nanoparticulate pharmaceutical drug delivery systems (NDDSs) to enhance the in vivo effectiveness of drugs is now well established. The development of multifunctional and stimulus-sensitive NDDSs is an active area of current research. Such NDDSs can have long circulation times, target the site of the disease and enhance the intracellular delivery of a drug. This type of NDDS can also respond to local stimuli that are characteristic of the pathological site by, for example, releasing an entrapped drug or shedding a protective coating, thus facilitating the interaction between drug-loaded nanocarriers and target cells or tissues. In addition, imaging contrast moieties can be attached to these carriers to track their real-time biodistribution and accumulation in target cells or tissues. Here, I highlight recent developments with multifunctional and stimuli-sensitive NDDSs and their therapeutic potential for diseases including cancer, cardiovascular diseases and infectious diseases. PMID:25287120

  14. Glycosides as possible lead antimalarial in new drug discovery: future perspectives.

    PubMed

    Marya; Khan, Haroon; Ahmad, Izhar

    2017-01-15

    Malaria remains one of the major public health problems worldwide and is responsible for a large number of morbidity and mortality. Especially, in the third world countries, it is still alarming. The development of drug-resistant to Plasmodium falciparum strains has further degraded the overall situation. However, a limited number of effective drugs available emphasizes how essential it is to establish new anti-malarial compounds. New antimalarial agents with distinctive structures and mechanism of action from the natural origin are thus immediately required to treat sensitive and drug-resistant strains of malaria. over the years, phytopharmaceuticals have provided numerous lead compounds. Similarly, the success rate of botanicals in terms of clinical significance is also very high. Of them, glycosides is one of the most widely distributed and emerging class of plant secondary metabolites. This review provides an outlook to recently isolated glycosides from plants with marked antimalarial effects in an in-vitro and in-vivo protocols and thus ideal candidates for clinical trials to ascertain their clinical utility and or led compounds.

  15. Multitask learning improves prediction of cancer drug sensitivity

    PubMed Central

    Yuan, Han; Paskov, Ivan; Paskov, Hristo; González, Alvaro J.; Leslie, Christina S.

    2016-01-01

    Precision oncology seeks to predict the best therapeutic option for individual patients based on the molecular characteristics of their tumors. To assess the preclinical feasibility of drug sensitivity prediction, several studies have measured drug responses for cytotoxic and targeted therapies across large collections of genomically and transcriptomically characterized cancer cell lines and trained predictive models using standard methods like elastic net regression. Here we use existing drug response data sets to demonstrate that multitask learning across drugs strongly improves the accuracy and interpretability of drug prediction models. Our method uses trace norm regularization with a highly efficient ADMM (alternating direction method of multipliers) optimization algorithm that readily scales to large data sets. We anticipate that our approach will enhance efforts to exploit growing drug response compendia in order to advance personalized therapy. PMID:27550087

  16. Summary of anti-malarial prophylactic efficacy of tafenoquine from three placebo-controlled studies of residents of malaria-endemic countries.

    PubMed

    Dow, Geoffrey S; Liu, Jun; Lin, Gina; Hetzell, Brian; Thieling, Sarah; McCarthy, William F; Tang, Douglas; Smith, Bryan

    2015-11-26

    Tafenoquine is a long half-life primaquine analog being developed for malaria prophylaxis. The US Army recently performed a unified analysis of efficacy in preparation for a regulatory submission, utilizing legacy data from three placebo-controlled studies conducted in the late 1990s and early 2000s. The subjects were residents of Africa who were naturally exposed to Plasmodium falciparum for 12-26 weeks. The prophylactic efficacy of tafenoquine and mefloquine (included in some studies as a comparator) was calculated using incidence density among subjects who had completed the three-day loading doses of study drug, had at least one maintenance dose and had at least one blood smear assessed during the prophylactic period. The three placebo-controlled studies were analysed separately and then in two pooled analyses: one for tafenoquine versus placebo (three studies) and one for tafenoquine and mefloquine versus placebo (two studies). The pooled protective efficacy (PE) of a tafenoquine regimen with three daily loading doses plus weekly maintenance at 200-mg for 10 weeks or longer (referred to as 200-mg weekly hereafter) relative to placebo in three placebo-controlled studies was 93.1 % [95 % confidence interval (CI) 89.1-95.6 %; total N = 492]. The pooled PEs of regimens of tafenoquine 200-mg weekly and mefloquine 250-mg weekly relative to placebo in two placebo-controlled studies (total N = 519) were 93.5 % (95 % CI 88.6-96.2 %) and 94.5 % (95 % CI 88.7-97.3 %), respectively. Three daily loading plus weekly maintenance doses of 50- and 100-mg, but not 25-mg, exhibited similar PEs. The PEs of tafenoquine regimens of a three-day loading dose at 400-mg with and without follow-up weekly maintenance doses at 400-mg were 93.7 % (95 % CI 85.4-97.3 %) and 81.0 % (95 % CI 66.8-89.1 %), respectively. Tafenoquine provided the same level of prophylactic efficacy as mefloquine in residents of Africa. These data support the prophylactic efficacy of tafenoquine and mefloquine that

  17. Virtual screen for repurposing approved and experimental drugs for candidate inhibitors of EBOLA virus infection

    PubMed Central

    Veljkovic, Veljko; Loiseau, Philippe M.; Figadere, Bruno; Glisic, Sanja; Veljkovic, Nevena; Perovic, Vladimir R.; Cavanaugh, David P.; Branch, Donald R.

    2015-01-01

    The ongoing Ebola virus epidemic has presented numerous challenges with respect to control and treatment because there are no approved drugs or vaccines for the Ebola virus disease (EVD). Herein is proposed simple theoretical criterion for fast virtual screening of molecular libraries for candidate inhibitors of Ebola virus infection. We performed a repurposing screen of 6438 drugs from DrugBank using this criterion and selected 267 approved and 382 experimental drugs as candidates for treatment of EVD including 15 anti-malarial drugs and 32 antibiotics. An open source Web server allowing screening of molecular libraries for candidate drugs for treatment of EVD was also established. PMID:25717373

  18. Stimuli sensitive hydrogels for ophthalmic drug delivery: A review

    PubMed Central

    Kushwaha, Swatantra KS; Saxena, Prachi; Rai, AK

    2012-01-01

    Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery. PMID:23119233

  19. Stimuli sensitive hydrogels for ophthalmic drug delivery: A review.

    PubMed

    Kushwaha, Swatantra Ks; Saxena, Prachi; Rai, Ak

    2012-04-01

    Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery.

  20. A link prediction approach to cancer drug sensitivity prediction.

    PubMed

    Turki, Turki; Wei, Zhi

    2017-10-03

    Predicting the response to a drug for cancer disease patients based on genomic information is an important problem in modern clinical oncology. This problem occurs in part because many available drug sensitivity prediction algorithms do not consider better quality cancer cell lines and the adoption of new feature representations; both lead to the accurate prediction of drug responses. By predicting accurate drug responses to cancer, oncologists gain a more complete understanding of the effective treatments for each patient, which is a core goal in precision medicine. In this paper, we model cancer drug sensitivity as a link prediction, which is shown to be an effective technique. We evaluate our proposed link prediction algorithms and compare them with an existing drug sensitivity prediction approach based on clinical trial data. The experimental results based on the clinical trial data show the stability of our link prediction algorithms, which yield the highest area under the ROC curve (AUC) and are statistically significant. We propose a link prediction approach to obtain new feature representation. Compared with an existing approach, the results show that incorporating the new feature representation to the link prediction algorithms has significantly improved the performance.

  1. Improving Drug Sensitivity Prediction Using Different Types of Data

    PubMed Central

    Hejase, HA; Chan, C

    2015-01-01

    The algorithms and models used to address the two subchallenges that are part of the NCI-DREAM (Dialogue for Reverse Engineering Assessments and Methods) Drug Sensitivity Prediction Challenge (2012) are presented. In subchallenge 1, a bidirectional search algorithm is introduced and optimized using an ensemble scheme and a nonlinear support vector machine (SVM) is then applied to predict the effects of the drug compounds on breast cancer cell lines. In subchallenge 2, a weighted Euclidean distance method is introduced to predict and rank the drug combinations from the most to the least effective in reducing the viability of a diffuse large B-cell lymphoma (DLBCL) cell line. PMID:26225231

  2. First evidence that drugs of abuse produce behavioral sensitization and cross sensitization in planarians.

    PubMed

    Rawls, Scott M; Patil, Tavni; Yuvasheva, Ekaternia; Raffa, Robert B

    2010-07-01

    Behavioral sensitization in mammals, including humans, is sensitive to factors such as administration route, testing environment, and pharmacokinetic confounds, unrelated to the drugs themselves that are difficult to eliminate. Simpler animals less susceptible to these confounding influences may be advantageous substitutes for studying sensitization. We tested this hypothesis by determining whether planarians display sensitization and cross sensitization to cocaine and glutamate. Planarian hyperactivity was quantified as the number of C-like hyperkinesias during a 1-min drug exposure. Planarians exposed initially to cocaine (or glutamate) on day 1 were challenged with cocaine (or glutamate) after 2 or 6 days of abstinence. Acute cocaine or glutamate produced concentration-related hyperactivity. Cocaine or glutamate challenge after 2 and 6 days of abstinence enhanced the hyperactivity, indicating the substances produced planarian behavioral sensitization. Cross-sensitization experiments showed that cocaine produced greater hyperactivity in planarians earlier exposed to glutamate than in glutamate-naive planarians, and vice versa. Behavioral responses were pharmacologically selective because neither scopolamine nor caffeine produced planarian behavioral sensitization despite causing hyperactivity after initial administration, and acute gamma-aminobutyric acid did not cause hyperactivity. Demonstration of pharmacologically selective behavioral sensitization in planarians suggests that these flatworms represent a sensitive in-vivo model to study cocaine behavioral sensitization and to screen potential abuse-deterrent therapeutics.

  3. Anti-malarial effect of gum arabic.

    PubMed

    Ballal, Adil; Bobbala, Diwakar; Qadri, Syed M; Föller, Michael; Kempe, Daniela; Nasir, Omaima; Saeed, Amal; Lang, Florian

    2011-05-20

    Gum Arabic (GA), a nonabsorbable nutrient from the exudate of Acacia senegal, exerts a powerful immunomodulatory effect on dendritic cells, antigen-presenting cells involved in the initiation of both innate and adaptive immunity. On the other hand GA degradation delivers short chain fatty acids, which in turn have been shown to foster the expression of foetal haemoglobin in erythrocytes. Increased levels of erythrocyte foetal haemoglobin are known to impede the intraerythrocytic growth of Plasmodium and thus confer some protection against malaria. The present study tested whether gum arabic may influence the clinical course of malaria. Human erythrocytes were in vitro infected with Plasmodium falciparum in the absence and presence of butyrate and mice were in vivo infected with Plasmodium berghei ANKA by injecting parasitized murine erythrocytes (1 × 10⁶) intraperitoneally. Half of the mice received gum arabic (10% in drinking water starting 10 days before the day of infection). According to the in vitro experiments butyrate significantly blunted parasitaemia only at concentrations much higher (3 mM) than those encountered in vivo following GA ingestion (<1 μM). According to the in vivo experiments the administration of gum arabic slightly but significantly decreased the parasitaemia and significantly extended the life span of infected mice. GA moderately influences the parasitaemia and survival of Plasmodium-infected mice. The underlying mechanism remained, however, elusive. Gum arabic favourably influences the course of murine malaria.

  4. Anti-malarial effect of gum arabic

    PubMed Central

    2011-01-01

    Background Gum Arabic (GA), a nonabsorbable nutrient from the exudate of Acacia senegal, exerts a powerful immunomodulatory effect on dendritic cells, antigen-presenting cells involved in the initiation of both innate and adaptive immunity. On the other hand GA degradation delivers short chain fatty acids, which in turn have been shown to foster the expression of foetal haemoglobin in erythrocytes. Increased levels of erythrocyte foetal haemoglobin are known to impede the intraerythrocytic growth of Plasmodium and thus confer some protection against malaria. The present study tested whether gum arabic may influence the clinical course of malaria. Methods Human erythrocytes were in vitro infected with Plasmodium falciparum in the absence and presence of butyrate and mice were in vivo infected with Plasmodium berghei ANKA by injecting parasitized murine erythrocytes (1 × 106) intraperitoneally. Half of the mice received gum arabic (10% in drinking water starting 10 days before the day of infection). Results According to the in vitro experiments butyrate significantly blunted parasitaemia only at concentrations much higher (3 mM) than those encountered in vivo following GA ingestion (<1 μM). According to the in vivo experiments the administration of gum arabic slightly but significantly decreased the parasitaemia and significantly extended the life span of infected mice. Discussion GA moderately influences the parasitaemia and survival of Plasmodium-infected mice. The underlying mechanism remained, however, elusive. Conclusions Gum arabic favourably influences the course of murine malaria. PMID:21599958

  5. First evidence that drugs of abuse produce behavioral sensitization and cross-sensitization in planarians

    PubMed Central

    Rawls, Scott M.; Patil, Tavni; Yuvasheva, Ekaternia; Raffa, Robert B.

    2010-01-01

    Behavioral sensitization in mammals, including humans, is sensitive to factors such as administration route, testing environment, and pharmacokinetic confounds, unrelated to the drugs themselves, that are difficult to eliminate. Simpler animals less susceptible to these confounding influences may be advantageous substitutes for studying sensitization. We tested this hypothesis by determining if planarians display sensitization and cross-sensitization to cocaine and glutamate. Planarian hyperactivity was quantified as the number of C-like hyperkinesias during a 1-min drug exposure. Planarians exposed initially to cocaine (or glutamate) on day 1 were challenged with cocaine (or glutamate) after 2 or 6 days of abstinence. Acute cocaine or glutamate produced concentration-related hyperactivity. Cocaine or glutamate challenge after 2 and 6 days of abstinence enhanced the hyperactivity, indicating the substances produced planarian behavioral sensitization (pBS). Cross-sensitization experiments showed that cocaine produced greater hyperactivity in planarians previously exposed to glutamate than in glutamate-naïve planarians, and vice versa. Behavioral responses were pharmacologically selective because neither scopolamine nor caffeine produced pBS despite causing hyperactivity after initial administration, and acute GABA did not cause hyperactivity. Demonstration of pharmacologically-selective behavioral sensitization in planarians suggests these flatworms represent a sensitive in vivo model to study cocaine behavioral sensitization and to screen potential abuse-deterrent therapeutics. PMID:20512030

  6. Transmission of HIV drug resistance: lessons from sensitive screening assays.

    PubMed

    Geretti, Anna Maria; Paredes, Roger; Kozal, Michael J

    2015-02-01

    The review discusses new technologies for the sensitive detection of HIV drug resistance, with a focus on applications in antiretroviral treatment (ART)-naïve populations. Conventional sequencing is well established for detecting HIV drug resistance in routine care and guides optimal treatment selection in patients starting ART. Access to conventional sequencing is nearly universal in Western countries, but remains limited in Asia, Latin America, and Africa. Technological advances now allow detection of resistance with greatly improved sensitivity compared with conventional sequencing, variably increasing the yield of resistance testing in ART-naïve populations. There is strong cumulative evidence from retrospective studies that sensitive detection of resistant mutants in baseline plasma samples lacking resistance by conventional sequencing more than doubles the risk of virological failure after starting efavirenz-based or nevirapine-based ART. Sensitive resistance testing methods are mainly confined to research applications and in this context have provided great insight into the dynamics of drug resistance development, persistence, and transmission. Adoption in care settings is becoming increasingly possible, although important challenges remain. Platforms for diagnostic use must undergo technical improvements to ensure good performance and ease of use, and clinical validation is required to ensure utility.

  7. Development of cultured Plasmodium falciparum blood-stage malaria cell banks for early phase in vivo clinical trial assessment of anti-malaria drugs and vaccines.

    PubMed

    Stanisic, Danielle I; Liu, Xue Q; De, Sai Lata; Batzloff, Michael R; Forbes, Tanya; Davis, Christopher B; Sekuloski, Silvana; Chavchich, Marina; Chung, Wendy; Trenholme, Katharine; McCarthy, James S; Li, Tao; Sim, B Kim Lee; Hoffman, Stephen L; Good, Michael F

    2015-04-07

    The ability to undertake controlled human malaria infection (CHMI) studies for preliminary evaluation of malaria vaccine candidates and anti-malaria drug efficacy has been limited by the need for access to sporozoite infected mosquitoes, aseptic, purified, cryopreserved sporozoites or blood-stage malaria parasites derived ex vivo from malaria infected individuals. Three different strategies are described for the manufacture of clinical grade cultured malaria cell banks suitable for use in CHMI studies. Good Manufacturing Practices (GMP)-grade Plasmodium falciparum NF54, clinically isolated 3D7, and research-grade P. falciparum 7G8 blood-stage malaria parasites were cultured separately in GMP-compliant facilities using screened blood components and then cryopreserved to produce three P. falciparum blood-stage malaria cell banks. These cell banks were evaluated according to specific criteria (parasitaemia, identity, viability, sterility, presence of endotoxin, presence of mycoplasma or other viral agents and in vitro anti-malarial drug sensitivity of the cell bank malaria parasites) to ensure they met the criteria to permit product release according to GMP requirements. The P. falciparum NF54, 3D7 and 7G8 cell banks consisted of >78% ring stage parasites with a ring stage parasitaemia of >1.4%. Parasites were viable in vitro following thawing. The cell banks were free from contamination with bacteria, mycoplasma and a broad panel of viruses. The P. falciparum NF54, 3D7 and 7G8 parasites exhibited differential anti-malarial drug susceptibilities. The P. falciparum NF54 and 3D7 parasites were susceptible to all anti-malaria compounds tested, whereas the P. falciparum 7G8 parasites were resistant/had decreased susceptibility to four compounds. Following testing, all defined release criteria were met and the P. falciparum cell banks were deemed suitable for release. Ethical approval has been obtained for administration to human volunteers. The production of cultured P

  8. Improvements in access to malaria treatment in Tanzania after switch to artemisinin combination therapy and the introduction of accredited drug dispensing outlets - a provider perspective.

    PubMed

    Alba, Sandra; Hetzel, Manuel W; Goodman, Catherine; Dillip, Angel; Liana, Jafari; Mshinda, Hassan; Lengeler, Christian

    2010-06-15

    To improve access to treatment in the private retail sector a new class of outlets known as accredited drug dispensing outlets (ADDO) was created in Tanzania. Tanzania changed its first-line treatment for malaria from sulphadoxine-pyrimethamine (SP) to artemether-lumefantrine (ALu) in 2007. Subsidized ALu was made available in both health facilities and ADDOs. The effect of these interventions on access to malaria treatment was studied in rural Tanzania. The study was carried out in the villages of Kilombero and Ulanga Demographic Surveillance System (DSS) and in Ifakara town. Data collection consisted of: 1) yearly censuses of shops selling drugs; 2) collection of monthly data on availability of anti-malarials in public health facilities; and 3) retail audits to measure anti-malarial sales volumes in all public, mission and private outlets. The data were complemented with DSS population data. Between 2004 and 2008 access to malaria treatment greatly improved and the number of anti-malarial treatment doses dispensed increased by 78%. Particular improvements were observed in the availability (from 0.24 shops per 1,000 people in 2004 to 0.39 in 2008) and accessibility (from 71% of households within 5 km of a shop in 2004 to 87% in 2008) of drug shops. Despite no improvements in affordability this resulted in an increase of the market share from 49% of anti-malarial sales 2005 to 59% in 2008. The change of treatment policy from SP to ALu led to severe stock-outs of SP in health facilities in the months leading up to the introduction of ALu (only 40% months in stock), but these were compensated by the wide availability of SP in shops. After the introduction of ALu stock levels of the drug were relatively high in public health facilities (over 80% months in stock), but the drug could only be found in 30% of drug shops and in no general shops. This resulted in a low overall utilization of the drug (19% of all anti-malarial sales) The public health and private retail

  9. Improvements in access to malaria treatment in Tanzania after switch to artemisinin combination therapy and the introduction of accredited drug dispensing outlets - a provider perspective

    PubMed Central

    2010-01-01

    Background To improve access to treatment in the private retail sector a new class of outlets known as accredited drug dispensing outlets (ADDO) was created in Tanzania. Tanzania changed its first-line treatment for malaria from sulphadoxine-pyrimethamine (SP) to artemether-lumefantrine (ALu) in 2007. Subsidized ALu was made available in both health facilities and ADDOs. The effect of these interventions on access to malaria treatment was studied in rural Tanzania. Methods The study was carried out in the villages of Kilombero and Ulanga Demographic Surveillance System (DSS) and in Ifakara town. Data collection consisted of: 1) yearly censuses of shops selling drugs; 2) collection of monthly data on availability of anti-malarials in public health facilities; and 3) retail audits to measure anti-malarial sales volumes in all public, mission and private outlets. The data were complemented with DSS population data. Results Between 2004 and 2008 access to malaria treatment greatly improved and the number of anti-malarial treatment doses dispensed increased by 78%. Particular improvements were observed in the availability (from 0.24 shops per 1,000 people in 2004 to 0.39 in 2008) and accessibility (from 71% of households within 5 km of a shop in 2004 to 87% in 2008) of drug shops. Despite no improvements in affordability this resulted in an increase of the market share from 49% of anti-malarial sales 2005 to 59% in 2008. The change of treatment policy from SP to ALu led to severe stock-outs of SP in health facilities in the months leading up to the introduction of ALu (only 40% months in stock), but these were compensated by the wide availability of SP in shops. After the introduction of ALu stock levels of the drug were relatively high in public health facilities (over 80% months in stock), but the drug could only be found in 30% of drug shops and in no general shops. This resulted in a low overall utilization of the drug (19% of all anti-malarial sales) Conclusions

  10. [Female urogenital mycoplasma infection and drug sensitivity status in Changsha].

    PubMed

    Zuo, Cheng-xin; Huang, Jin-hua; Chen, Jing; Lu, Jian-yun; Xiang, Ya-ping

    2006-06-01

    To survey mycoplasma infection in female urogenital tract and analyze the drug sensitivity of mycoplasma in Changsha. Ureaplasma urealyticum (Uu) and Mycoplasma hominis (Mh) were detected in 6566 cases of female urogenital tract infection by means of mycoplasma culture and drug sensitivity reagent kit. Sensitivity tests for 10 antibiotics were also performed. A total of 2938 cases were mycoplasma-positive (positivity rate of 44.75%), including 2469 Uu-positive cases (37.6%), 52 Mh-positive cases (0.08%) and 417 cases positive for both Uu and Mh (6.35%). Josamycin, doxycycline, clarithromycin and azithromycin were more effective against Uu infection. Josamycin, doxycycline and thiamphenicol were more effective against Mh infection. Mixed infection with Uu and Mh was more resistant to most antibiotics but Josamycin and doxycycline. The female urogenital mycoplasma infection results mainly from Uu. Compared with simple Uu or Mh infection, mixed infection with Uu and Mh has significantly greater resistance to a wider variety of drugs. Josamycin and doxycycline are the primary choice for female urogenital mycoplasma infection in Changsha.

  11. What happened to anti-malarial markets after the Affordable Medicines Facility-malaria pilot? Trends in ACT availability, price and market share from five African countries under continuation of the private sector co-payment mechanism.

    PubMed

    Tougher, Sarah; Hanson, Kara; Goodman, Catherine

    2017-04-25

    The private sector supplies anti-malarial treatment for large proportions of patients in sub-Saharan Africa. Following the large-scale piloting of the Affordable Medicines Facility-malaria (AMFm) from 2010 to 2011, a private sector co-payment mechanism (CPM) provided continuation of private sector subsidies for quality-assured artemisinin combination therapies (QAACT). This article analyses for the first time the extent to which improvements in private sector QAACT supply and distribution observed during the AMFm were maintained or intensified during continuation of the CPM through 2015 in Kenya, Madagascar, Nigeria, Tanzania and Uganda using repeat cross-sectional outlet survey data. QAACT market share in all five countries increased during the AMFm period (p < 0.001). According to the data from the last ACTwatch survey round, in all study countries except Madagascar, AMFm levels of private sector QAACT availability were maintained or improved. In 2014/15, private sector QAACT availability was greater than 70% in Nigeria (84.3%), Kenya (70.5%), Tanzania (83.0%) and Uganda (77.1%), but only 11.2% in Madagascar. QAACT market share was maintained or improved post-AMFm in Nigeria, Tanzania and Uganda, but statistically significant declines were observed in Kenya and Madagascar. In 2014/5, QAACT market share was highest in Kenya and Uganda (48.2 and 47.5%, respectively) followed by Tanzania (39.2%), Nigeria (35.0%), and Madagascar (7.0%). Four of the five countries experienced significant decreases in median QAACT price during the AMFm period. Private sector QAACT prices were maintained or further reduced in Tanzania, Nigeria and Uganda, but prices increased significantly in Kenya and Madagascar. SP prices were consistently lower than those of QAACT in the AMFm period, with the exception of Kenya and Tanzania in 2011, where they were equal. In 2014/5 QAACT remained two to three times more expensive than the most popular non-artemisinin therapy in all countries except

  12. Plasmodium falciparum Transfected with Ultra Bright NanoLuc Luciferase Offers High Sensitivity Detection for the Screening of Growth and Cellular Trafficking Inhibitors

    PubMed Central

    Elsworth, Brendan; Charnaud, Sarah C.; Sanders, Paul R.; Crabb, Brendan S.; Gilson, Paul R.

    2014-01-01

    Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc) luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients. PMID:25392998

  13. Fluoroquinolones for treating tuberculosis (presumed drug-sensitive).

    PubMed

    Ziganshina, Lilia E; Titarenko, Albina F; Davies, Geraint R

    2013-06-06

    Currently the World Health Organization only recommend fluoroquinolones for people with presumed drug-sensitive tuberculosis (TB) who cannot take standard first-line drugs. However, use of fluoroquinolones could shorten the length of treatment and improve other outcomes in these people. This review summarises the effects of fluoroquinolones in first-line regimens in people with presumed drug-sensitive TB. To assess fluoroquinolones as substitute or additional components in antituberculous drug regimens for drug-sensitive TB. We searched the Cochrane Infectious Diseases Group Specialized Register; CENTRAL (The Cochrane Library 2013, Issue 1); MEDLINE; EMBASE; LILACS; Science Citation Index; Databases of Russian Publications; and metaRegister of Controlled Trials up to 6 March 2013. Randomized controlled trials (RCTs) of antituberculous regimens based on rifampicin and pyrazinamide and containing fluoroquinolones in people with presumed drug-sensitive pulmonary TB. Two authors independently applied inclusion criteria, assessed the risk of bias in the trials, and extracted data. We used the risk ratio (RR) for dichotomous data and the fixed-effect model when it was appropriate to combine data and no heterogeneity was present. We assessed the quality of evidence using the GRADE approach. We identified five RCTs (1330 participants) that met the inclusion criteria. None of the included trials examined regimens of less than six months duration. Fluoroquinolones added to standard regimensA single trial (174 participants) added levofloxacin to the standard first-line regimen. Relapse and treatment failure were not reported. For death, sputum conversion, and adverse events we are uncertain if there is an effect (one trial, 174 participants, very low quality evidence for all three outcomes). Fluoroquinolones substituted for ethambutol in standard regimens Three trials (723 participants) substituted ethambutol with moxifloxacin, gatifloxacin, and ofloxacin into the standard

  14. Crosslinked ionic polysaccharides for stimuli-sensitive drug delivery.

    PubMed

    Alvarez-Lorenzo, Carmen; Blanco-Fernandez, Barbara; Puga, Ana M; Concheiro, Angel

    2013-08-01

    Polysaccharides are gaining increasing attention as components of stimuli-responsive drug delivery systems, particularly since they can be obtained in a well characterized and reproducible way from the natural sources. Ionic polysaccharides can be readily crosslinked to render hydrogel networks sensitive to a variety of internal and external variables, and thus suitable for switching drug release on-off through diverse mechanisms. Hybrids, composites and grafted polymers can reinforce the responsiveness and widen the range of stimuli to which polysaccharide-based systems can respond. This review analyzes the state of the art of crosslinked ionic polysaccharides as components of delivery systems that can regulate drug release as a function of changes in pH, ion nature and concentration, electric and magnetic field intensity, light wavelength, temperature, redox potential, and certain molecules (enzymes, illness markers, and so on). Examples of specific applications are provided. The information compiled demonstrates that crosslinked networks of ionic polysaccharides are suitable building blocks for developing advanced externally activated and feed-back modulated drug delivery systems.

  15. Targeting drug sensitivity predictors: New potential strategies to improve pharmacotherapy of human brain disorders.

    PubMed

    Kalueff, Allan V; Stewart, Adam Michael; Nguyen, Michael; Song, Cai; Gottesman, Irving I

    2015-12-03

    One of the main challenges in medicine is the lack of efficient drug therapies for common human disorders. For example, although depressed patients receive powerful antidepressants, many often remain resistant to psychopharmacotherapy. The growing recognition of complex interplay between the drug targets and the predictors of drug sensitivity requires an improved understanding of these two key aspects of drug action and their potentially shared molecular networks. Here, we apply the concept of endophenotypes and their interplay to drug action and sensitivity. Based on these analyses, we postulate that novel drugs may be developed by targeting specific molecular pathways that integrate drug targets with drug sensitivity predictors.

  16. Drug Sensitivity in Older Adults: The Role of Physiologic and Pharmacokinetic Factors.

    ERIC Educational Resources Information Center

    Cherry, Katie E.; Morton, Mark R.

    1989-01-01

    Notes that age-related changes in physiology and pharmacokinetics (how drugs are used in the body) lead to increased drug sensitivity and potentially harmful drug effects. Addresses heightened sensitivity to drug effects seen in older adults. Presents three examples of physiologic decline and discusses some broad considerations for geriatric…

  17. Should we continue or stop insulin sensitizing drugs during pregnancy?

    PubMed

    Norman, Robert J; Wang, Jim X; Hague, William

    2004-06-01

    The use of insulin sensitizing drugs such as metformin in polycystic ovary syndrome has been increasingly popular and validated by systematic reviews. There has also been an interest in the use of metformin for gestational diabetes. However, administration of metformin to prevent miscarriage is controversial and widespread use of this drug in early pregnancy requires investigation. There are claims that miscarriage and gestational diabetes are more common in polycystic ovary syndrome and that use of insulin sensitizers improves outcomes dramatically. This review suggests there is no evidence for increased risk of miscarriage solely due to polycystic ovary syndrome and that there are insufficient data for promoting therapy with metformin. There is some reason for use of metformin in mid-pregnancy for gestational diabetes but better evidence from randomized controlled trials is urgently needed. The use of metformin in early pregnancy for reducing the risk of miscarriage should be avoided outside of the context of properly designed prospective randomized trials. Safety in early pregnancy appears to be reassuring but not completely proven. The use of metformin in mid-pregnancy for gestational diabetes appears more logical but also needs adequate trials before general use is advocated.

  18. Numerical modeling of the transmission dynamics of drug-sensitive and drug-resistant HSV-2

    NASA Astrophysics Data System (ADS)

    Gumel, A. B.

    2001-03-01

    A competitive finite-difference method will be constructed and used to solve a modified deterministic model for the spread of herpes simplex virus type-2 (HSV-2) within a given population. The model monitors the transmission dynamics and control of drug-sensitive and drug-resistant HSV-2. Unlike the fourth-order Runge-Kutta method (RK4), which fails when the discretization parameters exceed certain values, the novel numerical method to be developed in this paper gives convergent results for all parameter values.

  19. Photoactive Fluoropolymer Surfaces that Release Sensitizer Drug Molecules

    PubMed Central

    Ghosh, Goutam; Minnis, Mihaela; Ghogare, Ashwini A.; Abramova, Inna; Cengel, Keith; Busch, Theresa M.; Greer, Alexander

    2015-01-01

    We describe a physical-organic study of two fluoropolymers bearing a photoreleasable PEGylated photosensitizer which generates 1O2(1Δg) [chlorin e6 methoxy tri(ethylene glycol) triester]. The surfaces are Teflon/polyvinylalcohol (PVA) nanocomposite and fluorinated silica. The relative efficiency of these surfaces to photorelease the PEGylated sensitizer [shown previously to be phototoxic to ovarian cancer cells (Kimani, S. et al J. Org. Chem 2012, 77, 10638)] was slightly higher for the nanocomposite. In the presence of red light and O2, 1O2 is formed, which cleaves an ethene linkage to liberate the sensitizer in 68–92% yields. The fluoropolymers were designed to deal with multiple problems. Namely, their success relied not only high O2 solubility and drug repellency, but that the C−F bonds physically quench little 1O2 for its productive use away from the surface. The results obtained here indicate that Teflon-like surfaces have potential uses of delivering sensitizer and singlet oxygen for applications in tissue repair and photodynamic therapy (PDT). PMID:25686407

  20. Photoactive fluoropolymer surfaces that release sensitizer drug molecules.

    PubMed

    Ghosh, Goutam; Minnis, Mihaela; Ghogare, Ashwini A; Abramova, Inna; Cengel, Keith A; Busch, Theresa M; Greer, Alexander

    2015-03-12

    We describe a physical-organic study of two fluoropolymers bearing a photoreleasable PEGylated photosensitizer that generates (1)O2((1)Δg) [chlorin e6 methoxy tri(ethylene glycol) triester]. The surfaces are Teflon/poly(vinyl alcohol) (PVA) nanocomposite and fluorinated silica. The relative efficiency of these surfaces to photorelease the PEGylated sensitizer [shown previously to be phototoxic to ovarian cancer cells (Kimani, S. et al. J. Org. Chem 2012, 77, 10638)] was slightly higher for the nanocomposite. In the presence of red light and O2, (1)O2 is formed, which cleaves an ethene linkage to liberate the sensitizer in 68-92% yield. The fluoropolymers were designed to deal with multiple problems. Namely, their success relied not only on high O2 solubility and drug repellency but also on the C-F bonds, which physically quench little (1)O2, for singlet oxygen's productive use away from the surface. The results obtained here indicate that Teflon-like surfaces have potential uses in delivering sensitizer and singlet oxygen for applications in tissue repair and photodynamic therapy (PDT).

  1. Plasmodium falciparum drug resistance in Angola.

    PubMed

    Fançony, Cláudia; Brito, Miguel; Gil, Jose Pedro

    2016-02-09

    Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information on malaria drug resistance in Angola, is reviewed and discussed. The review aims to inform but also to encourage future research studies that monitor and update the information on anti-malarial drug efficacy and prevalence of molecular markers of drug resistance, key fields in the context and objectives of elimination.

  2. hERG subunit composition determines differential drug sensitivity

    PubMed Central

    Abi-Gerges, N; Holkham, H; Jones, EMC; Pollard, CE; Valentin, J-P; Robertson, GA

    2011-01-01

    BACKGROUND AND PURPOSE The majority of human ether-a-go-go-related gene (hERG) screens aiming to minimize the risk of drug-induced long QT syndrome have been conducted using heterologous systems expressing the hERG 1a subunit, although both hERG 1a and 1b subunits contribute to the K+ channels producing the repolarizing current IKr. We tested a range of compounds selected for their diversity to determine whether hERG 1a and 1a/1b channels exhibit different sensitivities that may influence safety margins or contribute to a stratified risk analysis. EXPERIMENTAL APPROACH We used the IonWorks™ plate-based electrophysiology device to compare sensitivity of hERG 1a and 1a/1b channels stably expressed in HEK293 cells to 50 compounds previously shown to target hERG channels. Potency was determined as IC50 values (µM) obtained from non-cumulative, eight-point concentration–effect curves of normalized data, fitted to the Hill equation. To minimize possible sources of variability, compound potency was assessed using test plates arranged in alternating columns of cells expressing hERG 1a and 1a/1b. KEY RESULTS Although the potency of most compounds was similar for the two targets, some surprising differences were observed. Fluoxetine (Prozac) was more potent at blocking hERG 1a/1b than 1a channels, yielding a corresponding reduction in the safety margin. In contrast, E-4031 was a more potent blocker of hERG 1a compared with 1a/1b channels, as previously reported, as was dofetilide, another high-affinity blocker. CONCLUSIONS AND IMPLICATIONS The current assays may underestimate the risk of some drugs to cause torsades de pointes arrhythmia, and overestimate the risk of others. PMID:21449979

  3. Metabolic engineering of E.coli for the production of a precursor to artemisinin, an anti-malarial drug [Chapter 25 in Manual of Industrial Microbiology and Biotechnology, 3rd edition

    SciTech Connect

    Petzold, Christopher; Keasling, Jay

    2011-07-18

    This document is Chapter 25 in the Manual of Industrial Microbiology and Biotechnology, 3rd edition. Topics covered include: Incorporation of Amorpha-4,11-Diene Biosynthetic Pathway into E. coli; Amorpha-4,11-Diene Pathway Optimization; "-Omics" Analyses for Increased Amorpha-4,11-Diene Production; Biosynthetic Oxidation of Amorpha-4,11-Diene.

  4. The autophagy initiator ULK1 sensitizes AMPK to allosteric drugs.

    PubMed

    Dite, Toby A; Ling, Naomi X Y; Scott, John W; Hoque, Ashfaqul; Galic, Sandra; Parker, Benjamin L; Ngoei, Kevin R W; Langendorf, Christopher G; O'Brien, Matthew T; Kundu, Mondira; Viollet, Benoit; Steinberg, Gregory R; Sakamoto, Kei; Kemp, Bruce E; Oakhill, Jonathan S

    2017-09-18

    AMP-activated protein kinase (AMPK) is a metabolic stress-sensing enzyme responsible for maintaining cellular energy homeostasis. Activation of AMPK by salicylate and the thienopyridone A-769662 is critically dependent on phosphorylation of Ser108 in the β1 regulatory subunit. Here, we show a possible role for Ser108 phosphorylation in cell cycle regulation and promotion of pro-survival pathways in response to energy stress. We identify the autophagy initiator Unc-51-like kinase 1 (ULK1) as a β1-Ser108 kinase in cells. Cellular β1-Ser108 phosphorylation by ULK1 was dependent on AMPK β-subunit myristoylation, metabolic stress associated with elevated AMP/ATP ratio, and the intrinsic energy sensing capacity of AMPK; features consistent with an AMP-induced myristoyl switch mechanism. We further demonstrate cellular AMPK signaling independent of activation loop Thr172 phosphorylation, providing potential insight into physiological roles for Ser108 phosphorylation. These findings uncover new mechanisms by which AMPK could potentially maintain cellular energy homeostasis independently of Thr172 phosphorylation.AMPK is involved in sensing of metabolic stress. The authors show that the autophagy initiator ULK1 phosphorylates β1-Ser108 on the regulatory β1-subunit, sensitizing AMPK to allosteric drugs, and activates signaling pathways that appear independent of Thr172 phosphorylation in the kinase activation loop.

  5. [Sensitivity of salmonellae isolated from poultry to drugs].

    PubMed

    Stefanov, V; Kolev, K K; Stefanov, M

    1986-01-01

    Studied were a total of 125 Salmonella strains, isolated from birds, with regard to their sensitivity to medicinal drugs. A 100 percent effect against these organisms was found with amopen, neomycin, borgal, and sumetrolin. The effect was 97.7 per cent with canamycin, gentamycin, and terramycin; it was 95.5 per cent with the use of streptomycin, spectam, and chloramphenicol, 72.4 per cent--with tetracyclin, 70.5 per cent--with nalidixic acid, and 47.7 per cent--with sulfathiazol. Resistance of the strains to carbenicillin was 83 per cent, to ampicillin--79.6 per cent, and to sulfathiazol--38.6 per cent. It was interesting to note that resistance to carbenicillin and nalidixic acid, used in human medicine only, was 82.6 and 4.54 per cent, respectively. The high susceptibility of Salmonellae to amopen, and the limited capacity of the organisms to produce resistant strains outline the perspective of its wide use in the control of Salmonella infections in birds.

  6. The effect of carbon nanotubes on drug delivery in an electro-sensitive transdermal drug delivery system.

    PubMed

    Im, Ji S; Bai, Byong Ch; Lee, Young-Seak

    2010-02-01

    An electro-sensitive transdermal drug delivery system was prepared by the electrospinning method to control drug release. A semi-interpenetrating polymer network was prepared as the matrix with polyethylene oxide and pentaerythritol triacrylate polymers. Multi-walled carbon nanotubes were used as an additive to increase the electrical sensitivity. The release experiment was carried out under different electric voltage conditions. Carbon nanotubes were observed in the middle of the electrospun fibers by SEM and TEM. The amount of released drug was effectively increased with higher applied electric voltages. These results were attributed to the excellent electrical conductivity of the carbon additive. The suggested mechanism of drug release involves polyethylene oxide of the semi-interpenetrating polymer network being dissolved under the effects of carbon nanotubes, thereby releasing the drug. The effects of the electro-sensitive transdermal drug delivery system were enhanced by the carbon nanotubes.

  7. Predicting functional and regulatory divergence of a drug resistance transporter gene in the human malaria parasite.

    PubMed

    Siwo, Geoffrey H; Tan, Asako; Button-Simons, Katrina A; Samarakoon, Upeka; Checkley, Lisa A; Pinapati, Richard S; Ferdig, Michael T

    2015-02-22

    The paradigm of resistance evolution to chemotherapeutic agents is that a key coding mutation in a specific gene drives resistance to a particular drug. In the case of resistance to the anti-malarial drug chloroquine (CQ), a specific mutation in the transporter pfcrt is associated with resistance. Here, we apply a series of analytical steps to gene expression data from our lab and leverage 3 independent datasets to identify pfcrt-interacting genes. Resulting networks provide insights into pfcrt's biological functions and regulation, as well as the divergent phenotypic effects of its allelic variants in different genetic backgrounds. To identify pfcrt-interacting genes, we analyze pfcrt co-expression networks in 2 phenotypic states - CQ-resistant (CQR) and CQ-sensitive (CQS) recombinant progeny clones - using a computational approach that prioritizes gene interactions into functional and regulatory relationships. For both phenotypic states, pfcrt co-expressed gene sets are associated with hemoglobin metabolism, consistent with CQ's expected mode of action. To predict the drivers of co-expression divergence, we integrate topological relationships in the co-expression networks with available high confidence protein-protein interaction data. This analysis identifies 3 transcriptional regulators from the ApiAP2 family and histone acetylation as potential mediators of these divergences. We validate the predicted divergences in DNA mismatch repair and histone acetylation by measuring the effects of small molecule inhibitors in recombinant progeny clones combined with quantitative trait locus (QTL) mapping. This work demonstrates the utility of differential co-expression viewed in a network framework to uncover functional and regulatory divergence in phenotypically distinct parasites. pfcrt-associated co-expression in the CQ resistant progeny highlights CQR-specific gene relationships and possible targeted intervention strategies. The approaches outlined here can be

  8. Genomics of Drug Sensitivity in Cancer (GDSC): a resource for therapeutic biomarker discovery in cancer cells.

    PubMed

    Yang, Wanjuan; Soares, Jorge; Greninger, Patricia; Edelman, Elena J; Lightfoot, Howard; Forbes, Simon; Bindal, Nidhi; Beare, Dave; Smith, James A; Thompson, I Richard; Ramaswamy, Sridhar; Futreal, P Andrew; Haber, Daniel A; Stratton, Michael R; Benes, Cyril; McDermott, Ultan; Garnett, Mathew J

    2013-01-01

    Alterations in cancer genomes strongly influence clinical responses to treatment and in many instances are potent biomarkers for response to drugs. The Genomics of Drug Sensitivity in Cancer (GDSC) database (www.cancerRxgene.org) is the largest public resource for information on drug sensitivity in cancer cells and molecular markers of drug response. Data are freely available without restriction. GDSC currently contains drug sensitivity data for almost 75 000 experiments, describing response to 138 anticancer drugs across almost 700 cancer cell lines. To identify molecular markers of drug response, cell line drug sensitivity data are integrated with large genomic datasets obtained from the Catalogue of Somatic Mutations in Cancer database, including information on somatic mutations in cancer genes, gene amplification and deletion, tissue type and transcriptional data. Analysis of GDSC data is through a web portal focused on identifying molecular biomarkers of drug sensitivity based on queries of specific anticancer drugs or cancer genes. Graphical representations of the data are used throughout with links to related resources and all datasets are fully downloadable. GDSC provides a unique resource incorporating large drug sensitivity and genomic datasets to facilitate the discovery of new therapeutic biomarkers for cancer therapies.

  9. [Application of thermoplastic elastomer in hot-melt pressure sensitive adhesives for transtermal drug delivery].

    PubMed

    Yan, Xiaoping; Zheng, Rui; Guan, Shijie; Yi, Bowen

    2009-06-01

    Development of drug dosage forms to a great extent depends on the development of drug auxiliary materials. The development of a new type of polymeric drug auxiliary materials will bring on the developing of a novel dosage forms technology and a flood of new drug dosage forms. Thermoplastic elastomer is a new type of drug polymeric auxiliary materials, at present, which has a broad application in the field of hot-melt pressure sensitive adhesives. This review mainly discussed a new transtermal Chinese drug delivery system, including matrix composition of the formula, modified thermoplastic elastomer for hot-melt pressure sensitive adhesives and their development prospects in the traditional Chinese drug delivery system. It suggested that thermoplastic elastomer of hot-melt pressure sensitive adhesives has broad development prospects in the field of the transtermal drug delivery system for traditional Chinese medicine.

  10. 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

  11. New Insight into Isoprenoids Biosynthesis Process and Future Prospects for Drug Designing in Plasmodium

    PubMed Central

    Saggu, Gagandeep S.; Pala, Zarna R.; Garg, Shilpi; Saxena, Vishal

    2016-01-01

    The MEP (Methyl Erythritol Phosphate) isoprenoids biosynthesis pathway is an attractive drug target to combat malaria, due to its uniqueness and indispensability for the parasite. It is functional in the apicoplast of Plasmodium and its products get transported to the cytoplasm, where they participate in glycoprotein synthesis, electron transport chain, tRNA modification and several other biological processes. Several compounds have been tested against the enzymes involved in this pathway and amongst them Fosmidomycin, targeted against IspC (DXP reductoisomerase) enzyme and MMV008138 targeted against IspD enzyme have shown good anti-malarial activity in parasite cultures. Fosmidomycin is now-a-days prescribed clinically, however, less absorption, shorter half-life, and toxicity at higher doses, limits its use as an anti-malarial. The potential of other enzymes of the pathway as candidate drug targets has also been determined. This review details the various drug molecules tested against these targets with special emphasis to Plasmodium. We corroborate that MEP pathway functional within the apicoplast of Plasmodium is a major drug target, especially during erythrocytic stages. However, the major bottlenecks, bioavailability and toxicity of the new molecules needs to be addressed, before considering any new molecule as a potent antimalarial. PMID:27679614

  12. Ingenious pH-sensitive dextran/mesoporous silica nanoparticles based drug delivery systems for controlled intracellular drug release.

    PubMed

    Zhang, Min; Liu, Jia; Kuang, Ying; Li, Qilin; Zheng, Di-Wei; Song, Qiongfang; Chen, Hui; Chen, Xueqin; Xu, Yanglin; Li, Cao; Jiang, Bingbing

    2017-05-01

    In this work, dextran, a polysaccharide with excellent biocompatibility, is applied as the "gatekeeper" to fabricate the pH-sensitive dextran/mesoporous silica nanoparticles (MSNs) based drug delivery systems for controlled intracellular drug release. Dextran encapsulating on the surface of MSNs is oxidized by NaIO4 to obtain three kinds of dextran dialdehydes (PADs), which are then coupled with MSNs via pH-sensitive hydrazone bond to fabricate three kinds of drug carriers. At pH 7.4, PADs block the pores to prevent premature release of anti-cancer drug doxorubicin hydrochloride (DOX). However, in the weakly acidic intracellular environment (pH∼5.5) the hydrazone can be ruptured; and the drug can be released from the carriers. The drug loading capacity, entrapment efficiency and release rates of the drug carriers can be adjusted by the amount of NaIO4 applied in the oxidation reaction. And from which DOX@MSN-NH-N=C-PAD10 is chosen as the most satisfactory one for the further in vitro cytotoxicity studies and cellular uptake studies. The results demonstrate that DOX@MSN-NH-N=C-PAD10 with an excellent pH-sensitivity can enter HeLa cells to release DOX intracellular due to the weakly acidic pH intracellular and kill the cells. In our opinion, the ingenious pH-sensitive drug delivery systems have application potentials for cancer therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Drug release from pH-sensitive polymeric micelles with different drug distributions: insight from coarse-grained simulations.

    PubMed

    Nie, Shu Yu; Lin, Wen Jing; Yao, Na; Guo, Xin Dong; Zhang, Li Juan

    2014-10-22

    How to control the release of drugs from pH-sensitive polymeric micelles is an issue of common concern, which is important to the effectiveness of the micelles. The components and properties of polymers can notably influence the drug distributions inside micelles which is a key factor that affects the drug release from the micelles. In this work, the dissipative particle dynamics simulation method is first used to study the structural transformation of micelles during the protonation process and the drug release process from micelles with different drug distributions. And then the effects of polymer structures, including different lengths of hydrophilic blocks, pH-sensitive blocks and hydrophobic blocks, on drug release are also studied. In the end, several corresponding design principles of pH-sensitive polymers for drug delivery are proposed according to the simulation results. This work is in favor of establishing qualitative rules for the design and optimization of congener polymers for desired drug delivery, which is of great significance to provide a potential approach for the development of new multiblock pH-sensitive polymeric micelles.

  14. Triclosan derivatives: Towards potent inhibitors of drug-sensitive and drug-resistant Mycobacterium tuberculosis

    PubMed Central

    Freundlich, Joel S.; Wang, Feng; Vilchèze, Catherine; Gulten, Gulcin; Langley, Robert; Schiehser, Guy A.; Jacobus, David P.; Jacobs, William R.; Sacchettini, James C.

    2012-01-01

    Triclosan has been previously shown to inhibit InhA, an essential enoyl acyl carrier protein reductase of mycolic acid biosynthesis, whose inhibition leads to the lysis of Mycobacterium tuberculosis. Using a structure-based drug design approach, a series of 5-substituted derivatives of triclosan was developed. Two groups of triclosan derivatives with alkyl and aryl substituents, respectively, were identified with dramatically enhanced potency against purified InhA. The most efficacious inhibitor displayed an IC50 value of 21 nM, which was 50-fold more potent than triclosan. X-ray crystal structures of InhA in complex with four triclosan derivatives revealed the structural basis for the inhibitory activity. Six selected triclosan derivatives were tested against isoniazid-sensitive and resistant strains of M. tuberculosis. Among those, the best inhibitor had an MIC value of 4.7 µg/mL (13 µM), which represents a tenfold improvement over the bacteriocidal activity of triclosan. A subset of these triclosan analogs was more potent than isoniazid against two isoniazid-resistant M. tuberculosis strains, demonstrating the significant potential for structure-based design in the development of next generation antitubercular drugs. PMID:19130456

  15. Triclosan Derivatives: Towards Potent Inhibitors of Drug-Sensitive and Drug-Resistant Mycobacterium tuberculosis

    SciTech Connect

    Freundlich, Joel S.; Wang, Feng; Vilchèze, Catherine; Gulten, Gulcin; Langley, Robert; Schiehser, Guy A.; Jacobus, David P.; Jacobs, Jr., William R.; Sacchettini, James C.

    2009-06-30

    Isoniazid (INH) is a frontline antitubercular drug that inhibits the enoyl acyl carrier protein reductase InhA. Novel inhibitors of InhA that are not cross-resistant to INH represent a significant goal in antitubercular chemotherapy. The design, synthesis, and biological activity of a series of triclosan-based inhibitors is reported, including their promising efficacy against INH-resistant strains of M. tuberculosis. Triclosan has been previously shown to inhibit InhA, an essential enoyl acyl carrier protein reductase involved in mycolic acid biosynthesis, the inhibition of which leads to the lysis of Mycobacterium tuberculosis. Using a structure-based drug design approach, a series of 5-substituted triclosan derivatives was developed. Two groups of derivatives with alkyl and aryl substituents, respectively, were identified with dramatically enhanced potency against purified InhA. The most efficacious inhibitor displayed an IC{sub 50} value of 21 nM, which was 50-fold more potent than triclosan. X-ray crystal structures of InhA in complex with four triclosan derivatives revealed the structural basis for the inhibitory activity. Six selected triclosan derivatives were tested against isoniazid-sensitive and resistant strains of M. tuberculosis. Among those, the best inhibitor had an MIC value of 4.7 {mu}g mL{sup -1} (13 {mu}M), which represents a tenfold improvement over the bacteriocidal activity of triclosan. A subset of these triclosan analogues was more potent than isoniazid against two isoniazid-resistant M. tuberculosis strains, demonstrating the significant potential for structure-based design in the development of next generation antitubercular drugs.

  16. Identification of precision treatment strategies for relapsed/refractory multiple myeloma by functional drug sensitivity testing.

    PubMed

    Majumder, Muntasir Mamun; Silvennoinen, Raija; Anttila, Pekka; Tamborero, David; Eldfors, Samuli; Yadav, Bhagwan; Karjalainen, Riikka; Kuusanmäki, Heikki; Lievonen, Juha; Parsons, Alun; Suvela, Minna; Jantunen, Esa; Porkka, Kimmo; Heckman, Caroline A

    2017-08-22

    Novel agents have increased survival of multiple myeloma (MM) patients, however high-risk and relapsed/refractory patients remain challenging to treat and their outcome is poor. To identify novel therapies and aid treatment selection for MM, we assessed the ex vivo sensitivity of 50 MM patient samples to 308 approved and investigational drugs. With the results we i) classified patients based on their ex vivo drug response profile; ii) identified and matched potential drug candidates to recurrent cytogenetic alterations; and iii) correlated ex vivo drug sensitivity to patient outcome. Based on their drug sensitivity profiles, MM patients were stratified into four distinct subgroups with varied survival outcomes. Patients with progressive disease and poor survival clustered in a drug response group exhibiting high sensitivity to signal transduction inhibitors. Del(17p) positive samples were resistant to most drugs tested with the exception of histone deacetylase and BCL2 inhibitors. Samples positive for t(4;14) were highly sensitive to immunomodulatory drugs, proteasome inhibitors and several targeted drugs. Three patients treated based on the ex vivo results showed good response to the selected treatments. Our results demonstrate that ex vivo drug testing may potentially be applied to optimize treatment selection and achieve therapeutic benefit for relapsed/refractory MM.

  17. pH- and ion-sensitive polymers for drug delivery

    PubMed Central

    Yoshida, Takayuki; Lai, Tsz Chung; Kwon, Glen S; Sako, Kazuhiro

    2013-01-01

    Introduction Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body. Areas covered Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations. Expert opinion Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients. PMID:23930949

  18. pH- and ion-sensitive polymers for drug delivery.

    PubMed

    Yoshida, Takayuki; Lai, Tsz Chung; Kwon, Glen S; Sako, Kazuhiro

    2013-11-01

    Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body. Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations. Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients.

  19. Cytotoxicity of 15 Cameroonian medicinal plants against drug sensitive and multi-drug resistant cancer cells.

    PubMed

    Kuete, Victor; Djeussi, Doriane E; Mbaveng, Armelle T; Zeino, Maen; Efferth, Thomas

    2016-06-20

    Cameroonian medicinal plants are traditionally used to treat many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. It has been recommended that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants for anticancer screenings, since these reflect disease states bearing relevance to cancer or cancer-like symptoms. The present study aims at investigating 20 methanol extracts from 15 Cameroonian medicinal plants on a panel of human cancer cell lines, including various drug-resistant phenotypes. Possible modes of action of the of the most active plant were analyzed. Methanol extracts from different plant parts (leaves, bark, roots, fruits or whole plant) were evaluated for their cytotoxicity using resazurin reduction assay on a panel of nine sensitive and multi-drug resistant (MDR) cancer cell lines. Cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were measured by flow cytometry. Prescreening of extracts at 80µg/mL showed that 6 extracts out of 20 inhibited more than 50% proliferation of leukemia CCRF-CEM cells; these include extracts from Anthocleista schweinfurthii fruits (ASF; 48.28%), Morus mesozygia bark (MMB; 42.76%), Nauclea latifolia bark (NLB; 38.75%), Tridesmostemon omphalocarpoides bark (TOB; 38.53%), Nauclea latifolia leaves (NLL; 35.17%) and Erythrina sigmoidea bark (ESB; 33.77%). Subsequent investigations revealed IC50 values below or around 20µg/mL for extracts from MMB, NLB, NLL and ESB towards sensitive CCRF-CEM cells and its resistant P-glycoprotein over-expressing subline CEM/ADR5000. The best extract, ESB also displayed IC50 values below 20µg/mL colon carcinoma HCT116 (p53(+/+)) cells with an IC50 value of 19.63µg/mL and it resistant p53 knockout subline HCT116 (p53(-)(/-)) with an IC50 value of 16.22µg

  20. A framework for personalized medicine: prediction of drug sensitivity in cancer by proteomic profiling

    PubMed Central

    2012-01-01

    Background The goal of personalized medicine is to provide patients optimal drug screening and treatment based on individual genomic or proteomic profiles. Reverse-Phase Protein Array (RPPA) technology offers proteomic information of cancer patients which may be directly related to drug sensitivity. For cancer patients with different drug sensitivity, the proteomic profiling reveals important pathophysiologic information which can be used to predict chemotherapy responses. Results The goal of this paper is to present a framework for personalized medicine using both RPPA and drug sensitivity (drug resistance or intolerance). In the proposed personalized medicine system, the prediction of drug sensitivity is obtained by a proposed augmented naive Bayesian classifier (ANBC) whose edges between attributes are augmented in the network structure of naive Bayesian classifier. For discriminative structure learning of ANBC, local classification rate (LCR) is used to score augmented edges, and greedy search algorithm is used to find the discriminative structure that maximizes classification rate (CR). Once a classifier is trained by RPPA and drug sensitivity using cancer patient samples, the classifier is able to predict the drug sensitivity given RPPA information from a patient. Conclusion In this paper we proposed a framework for personalized medicine where a patient is profiled by RPPA and drug sensitivity is predicted by ANBC and LCR. Experimental results with lung cancer data demonstrate that RPPA can be used to profile patients for drug sensitivity prediction by Bayesian network classifier, and the proposed ANBC for personalized cancer medicine achieves better prediction accuracy than naive Bayes classifier in small sample size data on average and outperforms other the state-of-the-art classifier methods in terms of classification accuracy. PMID:22759571

  1. Advances in techniques of testing mycobacterial drug sensitivity, and the use of sensitivity tests in tuberculosis control programmes

    PubMed Central

    Canetti, G.; Fox, Wallace; Khomenko, A.; Mahler, H. T.; Menon, N. K.; Mitchison, D. A.; Rist, N.; Šmelev, N. A.

    1969-01-01

    In a paper arising out of an informal international consultation of specialists in the bacteriology of tuberculosis held in 1961, an attempt was made to formulate criteria, and specify technical procedures, for reliable tests of sensitivity (the absolute-concentration method, the resistance-ratio method and the proportion method) to the 3 main antituberculosis drugs (isoniazid, streptomycin and p-aminosalicylic acid). Seven years later, a further consultation was held to review the latest developments in the field and to suggest how sensitivity tests might be put to practical use in tuberculosis control programmes. The participants reached agreement on how to define drug sensitivity and resistance, and stressed the importance of using a discrimination approach to the calibration of sensitivity tests. Their views are contained in the present paper, which also includes descriptions of the sensitivity tests used by the Medical Research Council of Great Britain for first- and second-line drugs (minimal inhibitory concentration and resistance-ratio methods), the two main variants of the proportion method developed by the Institut Pasteur, Paris, and a method for calibrating sensitivity tests. PMID:5309084

  2. Pattern of drug utilization for treatment of uncomplicated malaria in urban Ghana following national treatment policy change to artemisinin-combination therapy.

    PubMed

    Dodoo, Alexander N O; Fogg, Carole; Asiimwe, Alex; Nartey, Edmund T; Kodua, Augustina; Tenkorang, Ofori; Ofori-Adjei, David

    2009-01-05

    Change of first-line treatment of uncomplicated malaria to artemisinin-combination therapy (ACT) is widespread in Africa. To expand knowledge of safety profiles of ACT, pharmacovigilance activities are included in the implementation process of therapy changes. Ghana implemented first-line therapy of artesunate-amodiaquine in 2005. Drug utilization data is an important component of determining drug safety, and this paper describes how anti-malarials were prescribed within a prospective pharmacovigilance study in Ghana following anti-malarial treatment policy change. Patients with diagnosis of uncomplicated malaria were recruited from pharmacies of health facilities throughout Accra in a cohort-event monitoring study. The main drug utilization outcomes were the relation of patient age, gender, type of facility attended, mode of diagnosis and concomitant treatments to the anti-malarial regimen prescribed. Logistic regression was used to predict prescription of nationally recommended first-line therapy and concomitant prescription of antibiotics. The cohort comprised 2,831 patients. Curative regimens containing an artemisinin derivative were given to 90.8% (n = 2,574) of patients, although 33% (n = 936) of patients received an artemisinin-based monotherapy. Predictors of first-line therapy were laboratory-confirmed diagnosis, age >5 years, and attending a government facility. Analgesics and antibiotics were the most commonly prescribed concomitant medications, with a median of two co-prescriptions per patient (range 1-9). Patients above 12 years were significantly less likely to have antibiotics co-prescribed than patients under five years; those prescribed non-artemisinin monotherapies were more likely to receive antibiotics. A dihydroartemisinin-amodiaquine combination was the most used therapy for children under five years of age (29.0%, n = 177). This study shows that though first-line therapy recommendations may change, clinical practice may still be affected by

  3. Shear-stress sensitive lenticular vesicles for targeted drug delivery.

    PubMed

    Holme, Margaret N; Fedotenko, Illya A; Abegg, Daniel; Althaus, Jasmin; Babel, Lucille; Favarger, France; Reiter, Renate; Tanasescu, Radu; Zaffalon, Pierre-Léonard; Ziegler, André; Müller, Bert; Saxer, Till; Zumbuehl, Andreas

    2012-08-01

    Atherosclerosis results in the narrowing of arterial blood vessels and this causes significant changes in the endogenous shear stress between healthy and constricted arteries. Nanocontainers that can release drugs locally with such rheological changes can be very useful. Here, we show that vesicles made from an artificial 1,3-diaminophospholipid are stable under static conditions but release their contents at elevated shear stress. These vesicles have a lenticular morphology, which potentially leads to instabilities along their equator. Using a model cardiovascular system based on polymer tubes and an external pump to represent shear stress in healthy and constricted vessels of the heart, we show that drugs preferentially release from the vesicles in constricted vessels that have high shear stress.

  4. Shear-stress sensitive lenticular vesicles for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Holme, Margaret N.; Fedotenko, Illya A.; Abegg, Daniel; Althaus, Jasmin; Babel, Lucille; Favarger, France; Reiter, Renate; Tanasescu, Radu; Zaffalon, Pierre-Léonard; Ziegler, André; Müller, Bert; Saxer, Till; Zumbuehl, Andreas

    2012-08-01

    Atherosclerosis results in the narrowing of arterial blood vessels and this causes significant changes in the endogenous shear stress between healthy and constricted arteries. Nanocontainers that can release drugs locally with such rheological changes can be very useful. Here, we show that vesicles made from an artificial 1,3-diaminophospholipid are stable under static conditions but release their contents at elevated shear stress. These vesicles have a lenticular morphology, which potentially leads to instabilities along their equator. Using a model cardiovascular system based on polymer tubes and an external pump to represent shear stress in healthy and constricted vessels of the heart, we show that drugs preferentially release from the vesicles in constricted vessels that have high shear stress.

  5. Fear Conditioning Effects on Sensitivity to Drug Reward

    DTIC Science & Technology

    2010-06-01

    morphine. Conditioned drug reward is a relevant model in addiction because environmental cues (e.g. a barroom) induce craving and persistent...2005). Cue-induced craving is predictive of relapse in addiction . Any improvements in our understanding of mechanisms of craving or conditioned...in reducing PTSD symptoms (Foa, 2006) and partially effective in the extinction of craving and relapse in addiction (Conklin and Tiffany, 2002

  6. Drug Loading Capacity of Environmentally Sensitive Polymeric Microgels

    NASA Astrophysics Data System (ADS)

    McDonough, Ryan; Streletzky, Kiril; Bayachou, Mekki; Peiris, Pubudu

    2009-10-01

    Microgel nanoparticles consisting of cross-linked polymer hydroxypropyl cellulose chains have a temperature dependent volume phase transition, prompting the use of microgels for controlled drug transport. Drug particles aggregate in the slightly hydrophobic interior of microgels. Microgels are stored in equilibrium until the critical temperature (Tv) is reached and the volume phase transition limits available space, thus expelling the drugs. Our study was designed to test this property of microgels using amperometric electrochemical methods. A critical assumption was that small molecules inside microgels would not interact via diffusion with the electrode surface and thus total current would be decreased across the electrodes in a microgel sample. A room temperature (Troom) flow amperometric measurement comparing microgel/tylenol solution with control tylenol samples yielded about 20% tylenol concentration reduction of the microgel sample. Results from the steady state electrochemical experiment confirm the presence of about 20% tylenol concentration drop of the microgel sample compared to control sample at Troom. Using the steady-state experiment with a cyclic temperature ramp from Troom to beyond Tv showed that the tylenol concentration change between the temperature extremes was greater for the microgel solution than for the control solution.

  7. Ultrasound-sensitive nanoparticle aggregates for targeted drug delivery.

    PubMed

    Papa, Anne-Laure; Korin, Netanel; Kanapathipillai, Mathumai; Mammoto, Akiko; Mammoto, Tadanori; Jiang, Amanda; Mannix, Robert; Uzun, Oktay; Johnson, Christopher; Bhatta, Deen; Cuneo, Garry; Ingber, Donald E

    2017-09-01

    Here we describe injectable, ultrasound (US)-responsive, nanoparticle aggregates (NPAs) that disintegrate into slow-release, nanoscale, drug delivery systems, which can be targeted to selective sites by applying low-energy US locally. We show that, unlike microbubble based drug carriers which may suffer from stability problems, the properties of mechanical activated NPAs, composed of polymer nanoparticles, can be tuned by properly adjusting the polymer molecular weight, the size of the nanoparticle precursors as well as the percentage of excipient utilized to hold the NPA together. We then apply this concept to practice by fabricating NPAs composed of nanoparticles loaded with Doxorubicin (Dox) and tested their ability to treat tumors via ultrasound activation. Mouse studies demonstrated significantly increased efficiency of tumor targeting of the US-activated NPAs compared to PLGA nanoparticle controls (with or without US applied) or intact NPAs. Importantly, when the Dox-loaded NPAs were injected and exposed to US energy locally, this increased ability to concentrate nanoparticles at the tumor site resulted in a significantly greater reduction in tumor volume compared to tumors treated with a 20-fold higher dose of the free drug. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Cell wall perturbation sensitizes fungi to the antimalarial drug chloroquine.

    PubMed

    Islahudin, Farida; Khozoie, Combiz; Bates, Steven; Ting, Kang-Nee; Pleass, Richard J; Avery, Simon V

    2013-08-01

    Chloroquine (CQ) has been a mainstay of antimalarial drug treatment for several decades. Additional therapeutic actions of CQ have been described, including some reports of fungal inhibition. Here we investigated the action of CQ in fungi, including the yeast model Saccharomyces cerevisiae. A genomewide yeast deletion strain collection was screened against CQ, revealing that bck1Δ and slt2Δ mutants of the cell wall integrity pathway are CQ hypersensitive. This phenotype was rescued with sorbitol, consistent with cell wall involvement. The cell wall-targeting agent caffeine caused hypersensitivity to CQ, as did cell wall perturbation by sonication. The phenotypes were not caused by CQ-induced changes to cell wall components. Instead, CQ accumulated to higher levels in cells with perturbed cell walls: CQ uptake was 2- to 3-fold greater in bck1Δ and slt2Δ mutants than in wild-type yeast. CQ toxicity was synergistic with that of the major cell wall-targeting antifungal drug, caspofungin. The MIC of caspofungin against the yeast pathogen Candida albicans was decreased 2-fold by 250 μM CQ and up to 8-fold at higher CQ concentrations. Similar effects were seen in Candida glabrata and Aspergillus fumigatus. The results show that the cell wall is critical for CQ resistance in fungi and suggest that combination treatments with cell wall-targeting drugs could have potential for antifungal treatment.

  9. Nullifying drug-induced sensitization: behavioral and electrophysiological evaluations of dopaminergic and serotonergic ligands in methamphetamine-sensitized rats.

    PubMed

    McDaid, J; Tedford, C E; Mackie, A R; Dallimore, J E; Mickiewicz, A L; Shen, F; Angle, J M; Napier, T C

    2007-01-05

    Repeated exposure to methamphetamine produces a persistent enhancement of the acute motor effects of the drug, commonly referred to as behavioral sensitization. Behavioral sensitization involves monoaminergic projections to several forebrain nuclei. We recently revealed that the ventral pallidum (VP) may also be involved. In this study, we sought to establish if treatments with antagonists or partial agonists to monoaminergic receptors could "reverse" methamphetamine-induced behavioral and VP neuronal sensitization. Behavioral sensitization was obtained in rats with five once-daily s.c. injections of 2.5mg/kg methamphetamine, an effect that persisted for at least 60 days. After the development of sensitization, 15 once-daily treatments of mirtazapine (a 5-HT(2/3), alpha(2) and H(1) antagonist), SKF38393 (D(1) partial agonist) or SCH23390 (dopamine D(1) antagonist) nullified indices of motor sensitization as assessed by measuring the motoric response to an acute methamphetamine challenge 30 days after the fifth repeated methamphetamine treatment. VP neurons recorded in vivo from methamphetamine-sensitized rats at the 30-day withdrawal time also showed a robust downward shift in the excitatory responses observed to an acute i.v. methamphetamine challenge in non-sensitized rats. This decreased excitatory effect was reversed by mirtazapine, but not by other antagonists that were tested. These data suggest a potential therapeutic benefit for mirtazapine in the treatment of methamphetamine addiction, and point to a possible role for the VP in the sensitization process to methamphetamine.

  10. In situ gelling stimuli-sensitive block copolymer hydrogels for drug delivery.

    PubMed

    He, Chaoliang; Kim, Sung Wan; Lee, Doo Sung

    2008-05-08

    Stimuli-sensitive block copolymer hydrogels, which are reversible polymer networks formed by physical interactions and exhibit a sol-gel phase-transition in response to external stimuli, have great potential in biomedical and pharmaceutical applications, especially in site-specific controlled drug-delivery systems. The drug may be mixed with a polymer solution in vitro and the drug-loaded hydrogel can form in situ after the in vivo administration, such as injection; therefore, stimuli-sensitive block copolymer hydrogels have many advantages, such as simple drug formulation and administration procedures, no organic solvent, site-specificity, a sustained drug release behavior, less systemic toxicity and ability to deliver both hydrophilic and hydrophobic drugs. Among the stimuli in the biomedical applications, temperature and pH are the most popular physical and chemical stimuli, respectively. The temperature- and/or pH-sensitive block copolymer hydrogels for biomedical applications have been extensively developed in the past decade. This review focuses on recent development of the preparation and application for drug delivery of the block copolymer hydrogels that respond to temperature, pH or both stimuli, including poly(N-substituted acrylamide)-based block copolymers, poloxamers and their derivatives, poly(ethylene glycol)-polyester block copolymers, polyelectrolyte-based block copolymers and the polyelectrolyte-modified thermo-sensitive block copolymers. In addition, the hydrogels based on other stimuli-sensitive block copolymers are discussed.

  11. Drugs affecting visceral sensitivity: ready for the prime time?

    PubMed

    Delvaux, Michel M; Gay, Gérard

    2006-01-01

    Visceral sensitivity has been recognized over the last decade as a frequent pathophysiological component of functional bowel disorders. Studies in animals and humans have identified numerous neurotransmitters involved in the processing of sensations from the gut to the brain. However, up to now none of them has actually been proven to have a marked clinical efficacy and the benefit comes rather from their action of bowel disturbances. Reproducible tests are lacking to detect visceral hypersensitivity in humans and distension tests are difficult to undertake in a clinical setting. Therefore, abnormal visceral sensitivity may not be regarded as a tool to select IBS patients as candidates for a given treatment. Copyright 2006 S. Karger AG, Basel.

  12. Development of pH-sensitive self-nanoemulsifying drug delivery systems for acid-labile lipophilic drugs.

    PubMed

    Zhao, Tianjing; Maniglio, Devid; Chen, Jie; Chen, Bin; Migliaresi, Claudio

    2016-03-01

    Oral administration is the most convenient way of all the drug delivery routes. Orally administered bioactive compounds must resist the harsh acidic fluids or enzyme digestion in stomach, to reach their absorbed destination in small intestine. This is the case for silibinin, a drug used to protect liver cells against toxins that has also been demonstrated in vitro to possess anti-cancer effects. However, as many other drugs, silibinin can degrade in the stomach due to the action of the gastric fluid. The use of pH-sensitive self-nanoemulsifying drug delivery systems (pH-SNEDDS) could overcome the drawback due to degradation of the drug in the stomach while enhancing its solubility and dissolution rate. In this paper we have investigated pH-sensitive self-nanoemulsifying formulations containing silibinin as model drug. Pseudo-ternary phase diagrams have been constructed in order to identify the self-emulsification regions under different pH. Solubility of silibinin in selected formulations has been assessed and stability of the pure drug and of the silibinin loaded pH-SNEDDS formulations in simulated gastric fluid had been compared. Droplet size of the optimized pH-SNEDDS has been correlated to pH, volume of dilution medium and silibinin loading amount. TEM (transmission electron microscopy) studies have shown that emulsion droplets had spherical shape and narrow size distribution. In vitro drug release studies of the optimal pH-SNEDDS indicated substantial increase of the drug release and release rate in comparison to pure silibinin and to the commercial silibinin tablet. The results indicated that pH-SNEDDS have potential to improve the biopharmaceutics properties of acid-labile lipophilic drugs.

  13. Computational analysis of ABL kinase mutations allows predicting drug sensitivity against selective kinase inhibitors.

    PubMed

    Kamasani, Swapna; Akula, Sravani; Sivan, Sree Kanth; Manga, Vijjulatha; Duyster, Justus; Vudem, Dashavantha Reddy; Kancha, Rama Krishna

    2017-05-01

    The ABL kinase inhibitor imatinib has been used as front-line therapy for Philadelphia-positive chronic myeloid leukemia. However, a significant proportion of imatinib-treated patients relapse due to occurrence of mutations in the ABL kinase domain. Although inhibitor sensitivity for a set of mutations was reported, the role of less frequent ABL kinase mutations in drug sensitivity/resistance is not known. Moreover, recent reports indicate distinct resistance profiles for second-generation ABL inhibitors. We thus employed a computational approach to predict drug sensitivity of 234 point mutations that were reported in chronic myeloid leukemia patients. Initial validation analysis of our approach using a panel of previously studied frequent mutations indicated that the computational data generated in this study correlated well with the published experimental/clinical data. In addition, we present drug sensitivity profiles for remaining point mutations by computational docking analysis using imatinib as well as next generation ABL inhibitors nilotinib, dasatinib, bosutinib, axitinib, and ponatinib. Our results indicate distinct drug sensitivity profiles for ABL mutants toward kinase inhibitors. In addition, drug sensitivity profiles of a set of compound mutations in ABL kinase were also presented in this study. Thus, our large scale computational study provides comprehensive sensitivity/resistance profiles of ABL mutations toward specific kinase inhibitors.

  14. Effect of drug physicochemical properties on drug release and their relationship with drug skin permeation behaviors in hydroxyl pressure sensitive adhesive.

    PubMed

    Liu, Chao; Quan, Peng; Fang, Liang

    2016-10-10

    The aim of this study was to investigate the influence of drug physicochemical properties on drug release behaviors and their relationship with skin permeation behaviors, which provided transdermal enhancement strategies for the design of transdermal drug delivery system. Six model drugs with different physicochemical properties were selected and hydroxyl pressure sensitive adhesive (PSA) was synthesized. Horizontal diffusion cell was used to evaluate drug release and skin permeation behaviors. The relationship between physicochemical properties and release behaviors was conducted with regression analysis. Release behavior of 0.25% drug loading was linear related with polar surface area, which represented the hydrogen bond. Release behavior of 2.0% drug loading was dependent on the polarizability and log P, which represented dipole-dipole interaction and lipophilicity, respectively. According to the results of Fourier transform infrared spectroscopy, it was inferred that hydrogen bond was limited in controlling release of drug due to the limited quantity of bonding site, thus dipole-dipole interaction and log P became dominate control factors. Combining the drug release study and drug skin permeation study, it was concluded that drugs with different physicochemical properties should be applied with different transdermal enhancement strategies, which was useful for the design of transdermal drug delivery system. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Sensitization to petrolatum: an unusual cause of false-positive drug patch-tests.

    PubMed

    Ulrich, G; Schmutz, J L; Trechot, Ph; Commun, N; Barbaud, A

    2004-09-01

    We report on an unexpected sensitization to petrolatum diagnosed with the occurrence of multiple nonrelevant and false-positive drug patch-tests performed while investigating a patient suffering from many cutaneous adverse drug reactions. All the positive drug patch-tests were prepared with GILBERT vaseline. This petrolatum reaction is positive as it was tested with five other brands of petrolatums a few months later. As the same petrolatums, but from different batches were tested, patch-tests with GILBERT petrolatum were doubtful, while other petrolatums were positive. White petrolatum is a mixture of semisolid hydrocarbons of the methane series. The sensitizing impurities of petrolatum are polycyclic aromatic hydrocarbons, e.g. phenanthrene derivatives. The purity of petrolatum depends on both the petroleum stock and on the production and packaging methods. Even if rare, contact sensitization to petrolatum can disturb the interpretation of drug patch-tests. It is necessary in the interpretation of drug patch-tests to test both in petrolatum and other vehicles and with all the different petrolatums used in preparing the material for drug patch-tests. So, it is essential to advise the patients sensitized to petrolatum to remove all the topical drugs, such as all the cosmetics, which contain petrolatum in their formulation.

  16. [Factors affecting the in vitro microtest for drug sensitivity of Plasmodium falciparum].

    PubMed

    Feng, Xiao-ping; Liu, De-quan

    2003-01-01

    To explore factors influencing the results of in vitro microtest for drug sensitivity of Plasmodium falciparum (Pf). Handy media, microplates predisposed with antimalarial drug, cultured Pf parasites (FCC-1/HN isolate) and blood samples from patients were used to evaluate the factors influencing the in vitro determination of drug sensitivity of Pf. Liquid medium and lyophilized medium stored at 4 degrees C for 2 months and 1 year respectively could keep their effect unchanged. The effect of the drug-coated plates was not changed within the following period of storage: plates coated with chloroquine and piperaquine stored at 4 degrees C for 2 years and 6 months respectively; plates coated with pyronaridine and artesunate stored at 4 degrees C for 3 months. The adhesive paper of the sealed plate could be unsealed once only. The plastic plate must be harmless to the growing of parasites. The drug liquid should not be stored over 2 wk at 4 degrees C; otherwise the drug concentration was changed. Parasites tested were at synchronous ring stage, with a density of 1,000-80,000/microliter blood, stored at room temperature for 1 h, and at 4 degrees C for 48 h. Operation needed to follow strictly the standard technical procedure. Drug plates, media, adhesive paper, parasites and operation technique can affect the result of in vitro microtest for drug sensitivity of P. falciparum. Standardized materials and operational procedure should be used to guarantee a reliable result of the test.

  17. A Network Flow-Based Method to Predict Anticancer Drug Sensitivity

    PubMed Central

    Qin, Yufang; Chen, Ming; Wang, Haiyun; Zheng, Xiaoqi

    2015-01-01

    Predicting anticancer drug sensitivity can enhance the ability to individualize patient treatment, thus making development of cancer therapies more effective and safe. In this paper, we present a new network flow-based method, which utilizes the topological structure of pathways, for predicting anticancer drug sensitivities. Mutations and copy number alterations of cancer-related genes are assumed to change the pathway activity, and pathway activity difference before and after drug treatment is used as a measure of drug response. In our model, Contributions from different genetic alterations are considered as free parameters, which are optimized by the drug response data from the Cancer Genome Project (CGP). 10-fold cross validation on CGP data set showed that our model achieved comparable prediction results with existing elastic net model using much less input features. PMID:25992881

  18. Ototoxic drugs: difference in sensitivity between mice and guinea pigs.

    PubMed

    Poirrier, A L; Van den Ackerveken, P; Kim, T S; Vandenbosch, R; Nguyen, L; Lefebvre, P P; Malgrange, B

    2010-03-01

    The development of experimental animal models has played an invaluable role in understanding the mechanisms of neurosensory deafness and in devising effective treatments. The purpose of this study was to develop an adult mouse model of ototoxic drug-induced hearing loss and to compare the ototoxicity in the adult mouse to that in the well-described guinea pig model. Mice are a powerful model organism, especially due to the large availability of antibodies, probes and genetic mutants. In this study, mice (n=114) and guinea pigs (n=35) underwent systemic treatment with either kanamycin or cisplatin. Auditory brainstem responses showed a significant threshold shift in guinea pigs 2 weeks after the beginning of the ototoxic treatment, while there was no significant hearing impairment recorded in mice. Hair cells and neuronal loss were correlated with hearing function in both guinea pigs and mice. These results indicate that the mouse is not a good model for ototoxicity, which should be taken into consideration in all further investigations concerning ototoxicity-induced hearing loss.

  19. Drug predictive cues activate aversion-sensitive striatal neurons that encode drug seeking.

    PubMed

    Wheeler, Daniel S; Robble, Mykel A; Hebron, Emily M; Dupont, Matthew J; Ebben, Amanda L; Wheeler, Robert A

    2015-05-06

    Drug-associated cues have profound effects on an addict's emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking. Copyright © 2015 the authors 0270-6474/15/357215-11$15.00/0.

  20. Drug Predictive Cues Activate Aversion-Sensitive Striatal Neurons That Encode Drug Seeking

    PubMed Central

    Wheeler, Daniel S.; Robble, Mykel A.; Hebron, Emily M.; Dupont, Matthew J.; Ebben, Amanda L.

    2015-01-01

    Drug-associated cues have profound effects on an addict's emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking. PMID:25948270

  1. Structure of Prolyl-tRNA Synthetase-Halofuginone Complex Provides Basis for Development of Drugs against Malaria and Toxoplasmosis.

    PubMed

    Jain, Vitul; Yogavel, Manickam; Oshima, Yoshiteru; Kikuchi, Haruhisa; Touquet, Bastien; Hakimi, Mohamed-Ali; Sharma, Amit

    2015-05-05

    The Chinese herb Dichroa febrifuga has traditionally treated malaria-associated fever. Its active component febrifugine (FF) and derivatives such as halofuginone (HF) are potent anti-malarials. Here, we show that FF-based derivatives arrest parasite growth by direct interaction with and inhibition of the protein translation enzyme prolyl-tRNA synthetase (PRS). Dual administration of inhibitors that target different tRNA synthetases suggests high utility of these drug targets. We reveal the ternary complex structure of PRS-HF and adenosine 5'-(β,γ-imido)triphosphate where the latter facilitates HF integration into the PRS active site. Structural analyses also highlight spaces within the PRS architecture for HF derivatization of its quinazolinone, but not piperidine, moiety. We also show a remarkable ability of HF to kill the related human parasite Toxoplasma gondii, suggesting wider HF efficacy against parasitic PRSs. Hence, our cell-, enzyme-, and structure-based data on FF-based inhibitors strengthen the case for their inclusion in anti-malarial and anti-toxoplasmosis drug development efforts.

  2. Repurposing of antiparasitic drugs: the hydroxy-naphthoquinone buparvaquone inhibits vertical transmission in the pregnant neosporosis mouse model.

    PubMed

    Müller, Joachim; Aguado-Martínez, Adriana; Manser, Vera; Wong, Ho Ning; Haynes, Richard K; Hemphill, Andrew

    2016-02-17

    The three anti-malarial drugs artemiside, artemisone, and mefloquine, and the naphthoquinone buparvaquone known to be active against theileriosis in cattle and Leishmania infections in rodents, were assessed for activity against Neospora caninum infection. All four compounds inhibited the proliferation of N. caninum tachyzoites in vitro with IC50 in the sub-micromolar range, but artemisone and buparvaquone were most effective (IC50 = 3 and 4.9 nM, respectively). However, in a neosporosis mouse model for cerebral infection comprising Balb/c mice experimentally infected with the virulent isolate Nc-Spain7, the three anti-malarial compounds failed to exhibit any activity, since treatment did not reduce the parasite burden in brains and lungs compared to untreated controls. Thus, these compounds were not further evaluated in pregnant mice. On the other hand, buparvaquone, shown earlier to be effective in reducing the parasite load in the lungs in an acute neosporosis disease model, was further assessed in the pregnant mouse model. Buparvaquone efficiently inhibited vertical transmission in Balb/c mice experimentally infected at day 7 of pregnancy, reduced clinical signs in the pups, but had no effect on cerebral infection in the dams. This demonstrates proof-of-concept that drug repurposing may lead to the discovery of an effective compound against neosporosis that can protect offspring from vertical transmission and disease.

  3. Drug-sensitive FGFR3 mutations in lung adenocarcinoma

    PubMed Central

    Chandrani, P.; Prabhash, K.; Prasad, R.; Sethunath, V.; Ranjan, M.; Iyer, P.; Aich, J.; Dhamne, H.; Iyer, D. N.; Upadhyay, P.; Mohanty, B.; Chandna, P.; Kumar, R.; Joshi, A.; Noronha, V.; Patil, V.; Ramaswamy, A.; Karpe, A.; Thorat, R.; Chaudhari, P.; Ingle, A.; Choughule, A.

    2017-01-01

    Background Lung cancer is the leading cause of cancer-related deaths across the world. In this study, we present therapeutically relevant genetic alterations in lung adenocarcinoma of Indian origin. Materials and methods Forty-five primary lung adenocarcinoma tumors were sequenced for 676 amplicons using RainDance cancer panel at an average coverage of 1500 × (reads per million mapped reads). To validate the findings, 49 mutations across 23 genes were genotyped in an additional set of 363 primary lung adenocarcinoma tumors using mass spectrometry. NIH/3T3 cells over expressing mutant and wild-type FGFR3 constructs were characterized for anchorage independent growth, constitutive activation, tumor formation and sensitivity to FGFR inhibitors using in vitro and xenograft mouse models. Results We present the first spectrum of actionable alterations in lung adenocarcinoma tumors of Indian origin, and shows that mutations of FGFR3 are present in 20 of 363 (5.5%) patients. These FGFR3 mutations are constitutively active and oncogenic when ectopically expressed in NIH/3T3 cells and using a xenograft model in NOD/SCID mice. Inhibition of FGFR3 kinase activity inhibits transformation of NIH/3T3 overexpressing FGFR3 constructs and growth of tumors driven by FGFR3 in the xenograft models. The reduction in tumor size in the mouse is paralleled by a reduction in the amounts of phospho-ERK, validating the in vitro findings. Interestingly, the FGFR3 mutations are significantly higher in a proportion of younger patients and show a trend toward better overall survival, compared with patients lacking actionable alterations or those harboring KRAS mutations. Conclusion We present the first actionable mutation spectrum in Indian lung cancer genome. These findings implicate FGFR3 as a novel therapeutic in lung adenocarcinoma. PMID:27998968

  4. Withanolide D Exhibits Similar Cytostatic Effect in Drug-Resistant and Drug-Sensitive Multiple Myeloma Cells.

    PubMed

    Issa, Mark E; Wijeratne, E M K; Gunatilaka, A A L; Cuendet, Muriel

    2017-01-01

    In spite of recent therapeutic advances, multiple myeloma (MM) remains a malignancy with very low curability. This has been partly attributed to the existence of a drug-resistant subpopulation known as cancer stem cells (CSCs). MM-CSCs are equipped with the necessary tools that render them highly resistant to virtually all conventional therapies. In this study, the growth inhibitory effects of withanolide D (WND), a steroidal lactone isolated from Withania somnifera, on drug-sensitive tumoral plasma cells and drug-resistant MM cells have been investigated. In MTT/XTT assays, WND exhibited similar cytostatic effects between drug-resistant and drug-sensitive cell lines in the nM range. WND also induced cell death and apoptosis in MM-CSCs and RPMI 8226 cells, as examined by the calcein/ethidium homodimer and annexin V/propidium iodide stainings, respectively. To determine whether P-glycoprotein (P-gp) efflux affected the cytostatic activity of WND, P-gp was inhibited with verapamil and results indicated that the WND cytostatic effect in MM-CSCs was independent of P-gp efflux. Furthermore, WND did not increase the accumulation of the fluorescent P-gp substrate rhodamine 123 in MM-CSCs, suggesting that WND may not inhibit P-gp at the tested relevant doses. Therefore, the WND-induced cytostatic effect may be independent of P-gp efflux. These findings warrant further investigation of WND in MM-CSC animal models.

  5. Targeting CDKs with Roscovitine Increases Sensitivity to DNA Damaging Drugs of Human Osteosarcoma Cells

    PubMed Central

    Hattinger, Claudia Maria; Fanelli, Marilù; Versteeg, Rogier; Koster, Jan; Picci, Piero

    2016-01-01

    Cyclin-dependent kinase 2 (CDK2) has been reported to be essential for cell proliferation in several human tumours and it has been suggested as an appropriate target to be considered in order to enhance the efficacy of treatment regimens based on the use of DNA damaging drugs. We evaluated the clinical impact of CDK2 overexpression on a series of 21 high-grade osteosarcoma (OS) samples profiled by using cDNA microarrays. We also assessed the in vitro efficacy of the CDKs inhibitor roscovitine in a panel of drug-sensitive and drug-resistant human OS cell lines. OS tumour samples showed an inherent overexpression of CDK2, and high expression levels at diagnosis of this kinase appeared to negatively impact on clinical outcome. CDK2 expression also proved to be relevant for in vitro OS cells growth. These findings indicated CDK2 as a promising candidate therapeutic marker for OS and therefore we assessed the efficacy of the CDKs-inhibitor roscovitine in both drug-sensitive and -resistant OS cell lines. All cell lines resulted to be responsive to roscovitine, which was also able to increase the activity of cisplatin and doxorubicin, the two most active DNA damaging drugs used in OS chemotherapy. Our results indicated that combined treatment with conventional OS chemotherapeutic drugs and roscovitine may represent a new candidate intervention approach, which may be considered to enhance tumour cell sensitivity to DNA damaging drugs. PMID:27898692

  6. Targeting CDKs with Roscovitine Increases Sensitivity to DNA Damaging Drugs of Human Osteosarcoma Cells.

    PubMed

    Vella, Serena; Tavanti, Elisa; Hattinger, Claudia Maria; Fanelli, Marilù; Versteeg, Rogier; Koster, Jan; Picci, Piero; Serra, Massimo

    2016-01-01

    Cyclin-dependent kinase 2 (CDK2) has been reported to be essential for cell proliferation in several human tumours and it has been suggested as an appropriate target to be considered in order to enhance the efficacy of treatment regimens based on the use of DNA damaging drugs. We evaluated the clinical impact of CDK2 overexpression on a series of 21 high-grade osteosarcoma (OS) samples profiled by using cDNA microarrays. We also assessed the in vitro efficacy of the CDKs inhibitor roscovitine in a panel of drug-sensitive and drug-resistant human OS cell lines. OS tumour samples showed an inherent overexpression of CDK2, and high expression levels at diagnosis of this kinase appeared to negatively impact on clinical outcome. CDK2 expression also proved to be relevant for in vitro OS cells growth. These findings indicated CDK2 as a promising candidate therapeutic marker for OS and therefore we assessed the efficacy of the CDKs-inhibitor roscovitine in both drug-sensitive and -resistant OS cell lines. All cell lines resulted to be responsive to roscovitine, which was also able to increase the activity of cisplatin and doxorubicin, the two most active DNA damaging drugs used in OS chemotherapy. Our results indicated that combined treatment with conventional OS chemotherapeutic drugs and roscovitine may represent a new candidate intervention approach, which may be considered to enhance tumour cell sensitivity to DNA damaging drugs.

  7. Integrating Domain Specific Knowledge and Network Analysis to Predict Drug Sensitivity of Cancer Cell Lines

    PubMed Central

    Kim, Sebo; Sundaresan, Varsha; Zhou, Lei; Kahveci, Tamer

    2016-01-01

    One of fundamental challenges in cancer studies is that varying molecular characteristics of different tumor types may lead to resistance to certain drugs. As a result, the same drug can lead to significantly different results in different types of cancer thus emphasizing the need for individualized medicine. Individual prediction of drug response has great potential to aid in improving the clinical outcome and reduce the financial costs associated with prescribing chemotherapy drugs to which the patient’s tumor might be resistant. In this paper we develop a network based classifier (NBC) method for predicting sensitivity of cell lines to anticancer drugs from transcriptome data. In the literature, this strategy has been used for predicting cancer types. Here, we extend it to estimate sensitivity of cells from different tumor types to various anticancer drugs. Furthermore, we incorporate domain specific knowledge such as the use of apoptotic gene list and clinical dose information in our method to impart biological significance to the prediction. Our experimental results suggest that our network based classifier (NBC) method outperforms existing classifiers in estimating sensitivity of cell lines for different drugs. PMID:27607242

  8. Dual-function radiation sensitizers and bioreductive drugs: factors affecting cellular uptake and sensitizing efficiency in analogues of RSU 1069.

    PubMed

    Walling, J; Stratford, I J; Adams, G E; Stephens, M A

    1988-04-01

    Alkyl aziridine analogues of the hypoxic cell radiosensitizer RSU 1069 have been synthesized and one of these, RB 7040, containing the tetramethyl substituted aziridine, is a more efficient sensitizer in vitro than RSU 1069 (Ahmed et al., 1986). The extent to which variation in drug uptake can influence the sensitizing efficiency of RSU 1069 and its analogues has been investigated by determining the cellular uptake of these weakly basic sensitizers as a function of the pH of the extracellular medium (pHe) over the range 5.4-8.4. Following exposure of V79 cells to these agents for 1 h at room temperature, the ratio of intra- to extracellular concentration (Ci/Ce) was near unity at pH 5.4. Increasing pHe to 8.4 resulted in no change in the ratio Ci/Ce for RSU 1069 (pKa = 6.04). In contrast, the values of Ci/Ce increased three-fold for RSU 1165 (pKa = 7.38) and eleven-fold for RB 7040 (pKa = 8.45). Radiosensitization by RSU 1069 showed little dependence on pHe over the range studied, whereas increasing pH caused an apparent increase in sensitizing efficiency of both RSU 1165 and RB 7040. However, when the enhancement ratios for sensitization were normalized to take account of the effect of extracellular pH on drug uptake, efficiency of sensitization was independent of pHe. This study suggests that changes in basicity (pKa) may have wider potential for therapeutic exploitation on the basis of selective tumour uptake for this type of agent.

  9. Drug sensitivity patterns of HHV8 carrying body cavity lymphoma cell lines

    PubMed Central

    2011-01-01

    Background Primary effusion lymphoma (PEL) is a rare KSHV/HHV8-associated high-grade non-Hodgkin's lymphoma (NHL) of B-cell origin, characterized by serous effusions in body cavities. Most patients are HIV-infected men with severe immunosuppression and other HHV8-associated diseases such as Kaposi's sarcoma (KS). The prognosis for those infected is poor, with a median survival of less than 6 months in most cohorts. Sustained complete remission is rare. High-dose chemotherapy regimens are used to improve remission rate and survival. The aim of the present study was to compare the drug sensitivity pattern of the available primary effusion (body cavity based) lymphoma-derived cell lines in order to find additional, potentially effective drugs that are not included in current chemotherapy treatment protocols. Methods We have analyzed 11 cell lines against 27 frequently used cytostatic drugs in short term (3 days) survival assays using automated high throughput confocal microscopy. Results All cell lines showed a distinct, individual drug sensitivity pattern. Considering the in vitro used and clinically achieved drug concentration, Vinorelbine, Paclitaxel, Epirubicin and Daunorubicin were the most effective drugs. Conclusions We suggest that inclusion of the above drugs into PEL chemotherapy protocols may be justified. The heterogeneity in the drug response pattern however indicated that assay-guided individualized therapy might be required to optimize therapeutic response. PMID:21992895

  10. Novel pH-sensitive biodegradable polymeric drug delivery systems based on ketal polymers.

    PubMed

    Chen, Daquan; Wang, Hongbo

    2014-01-01

    This article reviews the recent developments on novel pH-sensitive ketal-based biodegradable polymeric drug delivery systems. Due to the degradation of ketal derivatives, neutral alcohols and ketones, ketal derivatives can be used to fabricate pH-degradable polymer with pH-degradable ketal linkages in new drug delivery systems by avoiding inflammatory problems. Due to the novelty of ketal polymers, there were few reports about ketal polymers. The review starts with a brief introduction to the pH-sensitive drug delivery system, followed by the structure, preparation and characterization techniques of ketal polymers. Thereafter, the promising applications in various diseases in relation to micro/nano drug carriers based on ketal polymers are summarized and discussed.

  11. Glutamate-Gated Chloride Channels of Haemonchus contortus Restore Drug Sensitivity to Ivermectin Resistant Caenorhabditis elegans

    PubMed Central

    Glendinning, Susan K.; Buckingham, Steven D.; Sattelle, David B.; Wonnacott, Susan; Wolstenholme, Adrian J.

    2011-01-01

    Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl) gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316) under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in some assays. C

  12. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

    PubMed

    Glendinning, Susan K; Buckingham, Steven D; Sattelle, David B; Wonnacott, Susan; Wolstenholme, Adrian J

    2011-01-01

    Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl) gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316) under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in some assays. C

  13. Acute sensitivity of FAST and SLOW mice to the effects of abused drugs on locomotor activity.

    PubMed

    Phillips, T J; Burkhart-Kasch, S; Gwiazdon, C C; Crabbe, J C

    1992-05-01

    The universal nature of the stimulant or euphoric effect of addictive drugs suggests that it may be an important predictor of a drug's addiction potential. Furthermore, assessment of stimulant sensitivity could be useful for predicting the liability of individuals to drug abuse. The stimulant actions of abused drugs from different pharmacological classes may share a common biological mechanism. We investigated this notion by assessing the drug responses relative to base-line locomotor activity of mice selectively bred for increased (FAST) and reduced (SLOW) sensitivity to ethanol-induced stimulation. FAST mice were more sensitive than SLOW mice to the stimulant effects of methanol (1.5-3.0 g/kg), t-butanol (0.2-0.6 g/kg), n-propanol (0.15-1.2 g/kg), pentobarbital (10-40 mg/kg) and phenobarbital (15-120 mg/kg). FAST and SLOW mice were similarly stimulated by d-amphetamine (1.25-10 mg/kg) and caffeine (2.5-20 mg/kg). The activity of FAST and SLOW mice was equally depressed by nicotine (0.5-2.0 mg/kg) and morphine (4-75 mg/kg). Finally, FAST mice were unaffected, whereas SLOW mice were depressed by diazepam (1-8 mg/kg). Selection for relative sensitivity to stimulation by ethanol has generalized to other alcohols and to barbiturates, but not to several other abused drugs, including amphetamine. The data presented here support a hypothesized common mechanism of stimulant action for alcohols and barbiturates, and suggest that differences in sensitivity to drug stimulant effects can be seen in the absence of dopamine system differences.

  14. pH-Sensitive drug delivery system based on modified dextrin coated mesoporous silica nanoparticles.

    PubMed

    Chen, Hongyu; Zheng, Diwei; Liu, Jia; Kuang, Ying; Li, Qilin; Zhang, Min; Ye, Haifeng; Qin, Hongyang; Xu, Yanglin; Li, Cao; Jiang, Bingbing

    2016-04-01

    In this work, a novel pH-sensitive drug delivery system based on modified dextrin coated mesoporous silica nanoparticles (MSNs), DOX@MSN-DDA-CL, are prepared. The dextrin grafting on the surface of MSNs is oxidized by KIO4 to obtain dextrin dialdehyde, which is then cross-linked by tetraethylenepentamine through a pH-sensitive Schiff's base. Under physiological conditions, the cross-linked dextrin dialdehyde blocks the pores to prevent premature release of model drug doxorubicin hydrochloride (DOX). In the weak acidic environment, pH 6.0 in this work, the Schiff's base can be hydrolyzed and released the drug. The in vitro drug release studies at different pHs prove the pH-sensitivity of DOX@MSN-DDA-CL. The cytotoxicity and cell internalization behavior are also investigated in detail. In vivo tissue distribution and pharmacokinetics with a H22-bearing mouse animal mode are also studied, prove that DOX@MSN-DDA-CL has a longer retention time than that of pure DOX and can accumulate in tumor region via enhanced permeation and retention and nanomaterials-induced endothelial cell leakiness effects. In conclusion, the pH-sensitive modified dextrin/MSNs complex drug delivery system has a great potential for cancer therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Tetrathiomolybdate sensitizes ovarian cancer cells to anticancer drugs doxorubicin, fenretinide, 5-fluorouracil and mitomycin C.

    PubMed

    Kim, Kyu Kwang; Lange, Thilo S; Singh, Rakesh K; Brard, Laurent; Moore, Richard G

    2012-04-13

    Our recent study showed that tetrathiomolybdate (TM), a drug to treat copper overload disorders, can sensitize drug-resistant endometrial cancer cells to reactive oxygen species (ROS)-generating anticancer drug doxorubicin. To expand these findings in the present study we explore TM efficacy in combination with a spectrum of ROS-generating anticancer drugs including mitomycin C, fenretinide, 5-fluorouracil and doxorubicin in ovarian cancer cells as a model system. The effects of TM alone or in combination with doxorubicin, mitomycin C, fenretinide, or 5-fluorouracil were evaluated using a sulforhodamine B assay. Flow cytometry was used to detect the induction of apoptosis and ROS generation. Immunoblot analysis was carried out to investigate changes in signaling pathways. TM potentiated doxorubicin-induced cytotoxicity and modulated key regulators of apoptosis (PARP, caspases, JNK and p38 MAPK) in SKOV-3 and A2780 ovarian cancer cell lines. These effects were linked to the increased production of ROS, as shown in SKOV-3 cells. ROS scavenging by ascorbic acid blocked the sensitization of cells by TM. TM also sensitized SKOV-3 to mitomycin C, fenretinide, and 5-fluorouracil. The increased cytotoxicity of these drugs in combination with TM was correlated with the activity of ROS, loss of a pro-survival factor (e.g. XIAP) and the appearance of a pro-apoptotic marker (e.g. PARP cleavage). Our data show that TM increases the efficacy of various anticancer drugs in ovarian cancer cells in a ROS-dependent manner.

  16. Review: Effect of drugs on human cough reflex sensitivity to inhaled capsaicin

    PubMed Central

    2012-01-01

    Capsaicin, the pungent extract of red peppers, has been used in clinical research for almost three decades. Capsaicin has gained favor as the provocative agent of choice to measure cough reflex sensitivity, as it induces cough in a safe, reproducible, and dose-dependent manner. One of the major uses of capsaicin cough challenge testing has been to evaluate the effect of a pharmacological intervention on the human cough reflex. The current review summarizes the published experience with capsaicin inhalation challenge in the evaluation of drug effects on cough reflex sensitivity. A notable contrast evident between studies demonstrating a drug effect (inhibition of cough reflex sensitivity) and those that do not, is the predominance of healthy volunteers as subjects in the latter. This observation suggests that subjects with pathological cough, rather than normal volunteers, comprise the optimal group in which to evaluate the effect of potential antitussive agents on human cough reflex sensitivity. PMID:23146824

  17. Prenatal tactile stimulation attenuates drug-induced behavioral sensitization, modifies behavior, and alters brain architecture.

    PubMed

    Muhammad, Arif; Kolb, Bryan

    2011-07-11

    Based on the findings of postnatal tactile stimulation (TS), a favorable experience in rats, the present study examined the influence of prenatal TS on juvenile behavior, adult amphetamine (AMPH) sensitization, and structural alteration in the prefrontal cortex (PFC) and the striatum. Female rats received TS through a baby hair brush throughout pregnancy, and the pups born were tested for open field locomotion, elevated plus maze (EPM), novel object recognition (NOR), and play fighting behaviors. Development and persistence of drug-induced behavioral sensitization in adults were tested by repeated AMPH administration and a challenge, respectively. Structural plasticity in the brain was assessed from the prefrontal cortical thickness and striatum size from serial coronal sections. The results indicate that TS females showed enhanced exploration in the open field. TS decreased the frequency of playful attacks whereas the response to face or evade an attack was not affected. Anxiety-like behavior and cognitive performance were not influenced by TS. AMPH administration resulted in gradual increase in locomotor activity (i.e., behavioral sensitization) that persisted at least for 2 weeks. However, both male and female TS rats exhibited attenuated AMPH sensitization compared to sex-matched controls. Furthermore, the drug-associated alteration in the prefrontal cortical thickness and striatum size observed in controls were prevented by TS experience. In summary, TS during prenatal development modified juvenile behavior, attenuated drug-induced behavioral sensitization in adulthood, and reorganized brain regions implicated in drug addiction. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Prevalence of cutaneous drug eruptions in adult Nigerians with HIV/AIDS.

    PubMed

    Salami, T A T; Asalu, A F; Samuel, S O

    2010-06-01

    Adverse cutaneous drug eruptions are dreaded complication of drug use and this is more so when it occurs in the setting of human immune virus (HIV) infection and acquired immune deficiency syndrome (AIDS). This study aims to look at the prevalence of cutaneous drug eruptions in adult Nigerians with HIV/AIDS and find out the etiological agents, outcome, and prognosis of such occurrence in Irrua Specialist Teaching Hospital, Irrua Edo State Nigeria. A retrospective study of cutaneous drug eruptions in patients with HIV/AIDS managed in this centre over the past five years (between January 2001 and December 2005 prior to initiation of antiretroviral therapy) was carried out. A total of 900 patients with HIV/AIDS were managed during this period (antiretroviral treatment was not available during this period). Twenty five of these patients (2.8%) not had cutaneous drug eruptions (2.8%). Erythema multiforme major or Steven Johnson Syndrome (SJS)-40% and Toxic epidermal necrolysis (TEN)-20% were the most frequent types of adverse cutaneous drug events found while combination antituberculosis agent of Isoniazid/Thiacethazone (64%) and anti malarial Sulphadoxine/Pyrimethamine (20%) were the notable culprit drugs found to be responsible for these. There was a 20% fatality rate. Treatment of tuberculosis which is the most common AIDS presenting illness with anti tuberculosis regimen that includes thiacethazone and the ready availability of anti malarials over the counter without prescription are responsible for the findings of this study. Avoiding drugs such as those found to be culprit agents in this study in patients with HIV/AIDS; right prescription practice by health practitioners as well as more intense health education of the public on the hazards of self prescription will all go a long way in minimising the occurrence of these events.

  19. Preparation and characterization of PEG-modified polyurethane pressure-sensitive adhesives for transdermal drug delivery.

    PubMed

    Chen, Xuemei; Liu, Wei; Zhao, Yanbing; Jiang, Lingyu; Xu, Huibi; Yang, Xiangliang

    2009-06-01

    The purpose of this work was to develop novel pressure-sensitive adhesives (PSAs) for transdermal drug-delivery systems (TDDS) with proper adhesive properties, hydrophilicity, biocompatibility and high drug loading. Polyethyleneglycol-modified polyurethane PSAs (PEG-PU-PSAs) were synthesized by prepolymerization method with PEG-modified co-polyether and hexamethylene diisocyanate. The effects of reaction temperature, catalyst, ratios of NCO/OH, co-polyether composition, and chain extender were investigated. Drug loading was studied by using thiamazole (hydrophilic drug), diclofenac sodium (slightly hydrophilic drug), and ibuprofen (lipophilic drug) as model drugs. In vitro drug-release kinetics obtained with Franz diffusion cell and dialysis membrane. The results showed that when reaction temperature at 80 degrees C, weight percentage of stannous octoate as catalyst at 0.05%, ratio of NCO/OH at 2.0-2.2, ratio of PEG/polypropylene glycol (PPG)/polytetramethylene ether glycol (PTMG) at 30/25-30/50-55, and weight percentage of glycol as chain extender at 4.5%, PEGPU-PSAs synthesized performed well on adhesive properties. Actually, PEG on the main chain of the PU could improve the hydrophilicity of PSAs, whereas PPG and PTMG could offer proper adhesive properties. Skin compatibility test on volunteers indicated that PEG-PU-PSAs would not cause any skin irritations. All the model drugs had excellent stabilizations in PEG-PU-PSAs. In vitro drug-release kinetics demonstrated that the drug release depended on drug-loading level and solubility of the drug. These experimental results indicated that PEG-PU-PSAs have good potential for applications in TDDS.

  20. Heat Shock Protein translocation induced by membrane fluidization increases tumor-cell sensitivity to chemotherapeutic drugs.

    PubMed

    Dempsey, Nina C; Ireland, H Elyse; Smith, Carly M; Hoyle, Christine F; Williams, John H H

    2010-10-28

    Treatment of chronic lymphocytic leukemia (CLL) remains a challenge due to the frequency of drug resistance amongst patients. Improving the delivery of chemotherapeutic agents while reducing the expression of anti-apoptotic Heat Shock Proteins (HSPs) within the cancer cells may facilitate in overcoming this drug resistance. We demonstrate for the first time that sub-lethal doses of chemotherapeutic agents can be combined with membrane fluidizing treatments to produce a significant increase in drug efficacy and apoptosis in vitro. We show that fluidizers result in a transient decrease in intracellular HSPs, resulting in increased tumor-cell sensitivity and a membrane-associated induction of HSP gene expression.

  1. Synthesis of a dextran based thermo-sensitive drug delivery system by gamma irradiation.

    PubMed

    Almeida, J F; Ferreira, P; Alves, P; Lopes, A; Gil, M H

    2013-10-01

    Gamma radiation was used as the initiator/crosslinker agent for the synthesis of thermo-sensitive hydrogel networks, under the form of membranes, using dextran and N-isopropylacrylamide. The prepared membranes were loaded with Ondansetron™, a potent antiemetic drug and tested as drug delivery systems. The characterization of the materials was accomplished by: Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, elemental analysis, lower critical solution temperature (LCST) determination, swelling behaviour evaluation, determination of surface energy by contact angle measurement and drug delivery kinetics studies. Also, the influence of irradiation time and temperature on the materials properties was evaluated.

  2. Development of an in vitro drug sensitivity assay for Trichuris muris first-stage larvae.

    PubMed

    Wimmersberger, David; Tritten, Lucienne; Keiser, Jennifer

    2013-02-22

    Trichuriasis represents a major public health problem in the developing world and is regarded as a neglected disease. Albendazole and mebendazole, the two drugs of choice against trichuriasis display only moderate cure rates, hence alternative drugs are needed. To identify candidate compounds, in vitro drug sensitivity testing currently relies on the adult Trichuris muris motility assay. The objective of the present study was to develop a simple and cost-effective drug sensitivity assay using Trichuris muris first-stage larvae (L1). Several potential triggers that induce hatching of T. muris were studied, including gastrointestinal enzymes, acidic environment and intestinal microflora. Next, optimal culture conditions for T. muris L1 were determined assessing a wide range of culture media. T. muris L1 were incubated in the presence of mebendazole, ivermectin, nitazoxanide, levamisole or oxantel pamoate at 37°C. The viability of the parasites was evaluated microscopically after 24 hours. The usefulness of fluorescent markers (resazurin, calcein AM, ethidium homodimer-1 or fluorescein-conjugated albumin) in drug sensitivity testing was also assessed. The established L1 motility assay provided accurate and reproducible drug effect data in vitro. IC50 values for oxantel pamoate, levamisole and nitazoxanide were 0.05, 1.75 and 4.43 μg/mL, respectively. Mebendazole and ivermectin failed to show any trichuricidal effect on L1. No correlation was found between data from the four fluorescent markers and the comparative motility assay. The motility assay based on L1 was found suitable for drug sensitivity screening. It is rather simple, cost-effective, time-saving and sustains medium-throughput testing. Furthermore, it greatly reduces the need for the animal host and is therefore more ethical. None of the viability markers assessed in this study were found to be satisfactory.

  3. Insulin-Like Growth Factor 2 Silencing Restores Taxol Sensitivity in Drug Resistant Ovarian Cancer

    PubMed Central

    Brouwer-Visser, Jurriaan; Lee, Jiyeon; McCullagh, KellyAnne; Cossio, Maria J.; Wang, Yanhua; Huang, Gloria S.

    2014-01-01

    Drug resistance is an obstacle to the effective treatment of ovarian cancer. We and others have shown that the insulin-like growth factor (IGF) signaling pathway is a novel potential target to overcome drug resistance. The purpose of this study was to validate IGF2 as a potential therapeutic target in drug resistant ovarian cancer and to determine the efficacy of targeting IGF2 in vivo. An analysis of The Cancer Genome Atlas (TCGA) data in the serous ovarian cancer cohort showed that high IGF2 mRNA expression is significantly associated with shortened interval to disease progression and death, clinical indicators of drug resistance. In a genetically diverse panel of ovarian cancer cell lines, the IGF2 mRNA levels measured in cell lines resistant to various microtubule-stabilizing agents including Taxol were found to be significantly elevated compared to the drug sensitive cell lines. The effect of IGF2 knockdown on Taxol resistance was investigated in vitro and in vivo. Transient IGF2 knockdown significantly sensitized drug resistant cells to Taxol treatment. A Taxol-resistant ovarian cancer xenograft model, developed from HEY-T30 cells, exhibited extreme drug resistance, wherein the maximal tolerated dose of Taxol did not delay tumor growth in mice. Blocking the IGF1R (a transmembrane receptor that transmits signals from IGF1 and IGF2) using a monoclonal antibody did not alter the response to Taxol. However, stable IGF2 knockdown using short-hairpin RNA in HEY-T30 effectively restored Taxol sensitivity. These findings validate IGF2 as a potential therapeutic target in drug resistant ovarian cancer and show that directly targeting IGF2 may be a preferable strategy compared with targeting IGF1R alone. PMID:24932685

  4. Drugs of abuse specifically sensitize noradrenergic and serotonergic neurons via a non-dopaminergic mechanism.

    PubMed

    Lanteri, Christophe; Salomon, Lucas; Torrens, Yvette; Glowinski, Jacques; Tassin, Jean-Pol

    2008-06-01

    A challenge in drug dependence is to delineate long-term neurochemical modifications induced by drugs of abuse. Repeated d-amphetamine was recently shown to disrupt a mutual regulatory link between noradrenergic and serotonergic neurons, thus inducing long-term increased responses to d-amphetamine and para-chloroamphetamine, respectively. We show here that such a sensitization of noradrenergic and serotonergic neurons also occurs following repeated treatment with cocaine, morphine, or alcohol, three compounds belonging to main groups of addictive substances. In all cases, this sensitization is prevented by alpha 1b-adrenergic and 5-HT2A receptors blockade, indicating the critical role of these receptors on long-term effects of drugs of abuse. However, repeated treatments with two non-addictive antidepressants, venlafaxine, and clorimipramine, which nevertheless inhibit noradrenergic and serotonergic reuptake, do not induce noradrenergic and serotonergic neurons sensitization. Similarly, this sensitization does not occur following repeated treatments with a specific inhibitor of dopamine (DA) reuptake, GBR12783. Moreover, we show that the effects of SCH23390, a D1 receptor antagonist known to inhibit development of d-amphetamine behavioral sensitization, are due to its 5-HT2C receptor agonist property. SCH23390 blocks amphetamine-induced release of norepinephrine and RS102221, a 5-HT2C antagonist, can reverse this inhibition as well as inhibition of noradrenergic sensitization and development of behavioral sensitization induced by repeated d-amphetamine. We propose that noradrenergic/serotonergic uncoupling is a common neurochemical consequence of repeated consumption of drugs of abuse, unrelated with DA release. Our data also suggest that compounds able to restore the link between noradrenergic and serotonergic modulatory systems could represent important therapeutic targets for investigation.

  5. Antimycobacterial activity of Citrullus colocynthis (L.) Schrad. against drug sensitive and drug resistant Mycobacterium tuberculosis and MOTT clinical isolates.

    PubMed

    Mehta, Archana; Srivastva, Garima; Kachhwaha, Sumita; Sharma, Meenakshi; Kothari, S L

    2013-08-26

    Citrullus colocynthis (Cucurbitaceae), a folk herbal medicine and traditionally used natural remedy for tuberculosis in India has been studied to validate its antitubercular activity against drug sensitive and drug resistant (including multidrug resistant) Mycobacterium tuberculosis and Mycobacterium other than tuberculosis (MOTT) bacilli. Inhibitory and bactericidal activities of crude extracts, fractions and compounds of Citrullus colocynthis plant, consisting of aerial parts and ripe deseeded fruits were performed against the drug sensitive standard strain of Mycobacterium tuberculosis H37Rv (ATCC 27294), 16 drug resistant strains of Mycobacterium tuberculosis and two MOTT strains, using radiometric BACTEC 460TB system. Methanolic extract of ripe deseeded fruit of Citrullus colocynthis has shown good activity (MIC ≤ 62.5 µg/ml), whereas among the bioactive fractions, FC IX demonstrated the best activity (MIC 31.2 µg/ml) against Mycobacterium tuberculosis H37Rv. Bioactive FC III, IX and X also inhibited 16 clinical isolates of Mycobacterium tuberculosis consisting of seven non-multidrug resistants, eight multidrug resistants, one extensively drug resistant and two of MOTTs with MICs in the range of 50-125, 31.2-125 and 62.5-125 µg/ml, respectively. Ursolic acid and cucurbitacin E 2-0-β-d-glucopyranoside were identified as the main biomarkers active against Mycobacterium tuberculosis H37Rv (MICs 50 and 25 µg/ml respectively), as well as against the 18 clinical isolates. FC III and FC IX showed better inhibition of drug resistant and MOTT clinical isolates. Minimal bactericidal concentrations of extracts, fractions and compound C-2 were ≥ two-fold MIC values. The study provides a scientific rationale for the traditional use of Citrullus colocynthis fruit in the treatment of tuberculosis. In addition, the study elucidates a broad spectrum antimycobacterial action of Citrullus colocynthis fruit, which can contribute to the development of improved preparation

  6. Genetic regulation of human anti-malarial antibodies in twins.

    PubMed Central

    Sjöberg, K; Lepers, J P; Raharimalala, L; Larsson, A; Olerup, O; Marbiah, N T; Troye-Blomberg, M; Perlmann, P

    1992-01-01

    Immune responses to defined antigens may differ between individuals in a population as the reflection of differences in genetic regulation. In experimental animals, variation in responsiveness to a given epitope may be due to major histocompatibility complex (HLA, in humans) class II restrictions, implying serious limitations for the development of subunit vaccines. For human populations, knowledge of the relative importance of genetic as opposed to environmental factors affecting the immune response is scarce. We have compared antibody levels after immunization through repeated infections to a major malarial antigen (Pf155/RESA) in monozygotic twins with those in dizygotic twins, siblings, or unrelated controls. Antibody responses to the intact antigen and to some of its immunodominant epitopes were found to be more concordant within monozygotic twin pairs than in dizygotic pairs or age- and sex-matched siblings living under similar environmental conditions. The results support the conclusion that the antibody responses were genetically regulated. When the responses were assessed for possible associations with different HLA class II DRB, DQA, and DQB alleles had haplotypes, no associations were found. This suggests that the regulation of the Pf155/RESA antibody responses seen in this study reflects the impact of factors encoded by genes outside the HLA class II regions. PMID:1549568

  7. Increased sensitivity to platinum drugs of cancer cells with acquired resistance to trabectedin

    PubMed Central

    Colmegna, B; Uboldi, S; Frapolli, R; Licandro, S A; Panini, N; Galmarini, C M; Badri, Nadia; Spanswick, V J; Bingham, J P; Kiakos, Konstantinos; Erba, E; Hartley, J A; D'Incalci, M

    2015-01-01

    Background: In order to investigate the mechanisms of acquired resistance to trabectedin, trabectedin-resistant human myxoid liposarcoma (402-91/T) and ovarian carcinoma (A2780/T) cell lines were derived and characterised in vitro and in vivo. Methods: Resistant cell lines were obtained by repeated exposures to trabectedin. Characterisation was performed by evaluating drug sensitivity, cell cycle perturbations, DNA damage and DNA repair protein expression. In vivo experiments were performed on A2780 and A2780/T xenografts. Results: 402-91/T and A2780/T cells were six-fold resistant to trabectedin compared with parental cells. Resistant cells were found to be hypersensitive to UV light and did not express specific proteins involved in the nucleotide excision repair (NER) pathway: XPF and ERCC1 in 402-91/T and XPG in A2780/T. NER deficiency in trabectedin-resistant cells was associated with the absence of a G2/M arrest induced by trabectedin and with enhanced sensitivity (two-fold) to platinum drugs. In A2780/T, this collateral sensitivity, confirmed in vivo, was associated with an increased formation of DNA interstrand crosslinks. Conclusions: Our finding that resistance to trabectedin is associated with the loss of NER function, with a consequent increased sensitivity to platinum drugs, provides the rational for sequential use of these drugs in patients who have acquired resistance to trabectedin. PMID:26633559

  8. A Copula Based Approach for Design of Multivariate Random Forests for Drug Sensitivity Prediction

    PubMed Central

    Haider, Saad; Rahman, Raziur; Ghosh, Souparno; Pal, Ranadip

    2015-01-01

    Modeling sensitivity to drugs based on genetic characterizations is a significant challenge in the area of systems medicine. Ensemble based approaches such as Random Forests have been shown to perform well in both individual sensitivity prediction studies and team science based prediction challenges. However, Random Forests generate a deterministic predictive model for each drug based on the genetic characterization of the cell lines and ignores the relationship between different drug sensitivities during model generation. This application motivates the need for generation of multivariate ensemble learning techniques that can increase prediction accuracy and improve variable importance ranking by incorporating the relationships between different output responses. In this article, we propose a novel cost criterion that captures the dissimilarity in the output response structure between the training data and node samples as the difference in the two empirical copulas. We illustrate that copulas are suitable for capturing the multivariate structure of output responses independent of the marginal distributions and the copula based multivariate random forest framework can provide higher accuracy prediction and improved variable selection. The proposed framework has been validated on genomics of drug sensitivity for cancer and cancer cell line encyclopedia database. PMID:26658256

  9. Anticancer drug clustering in lung cancer based on gene expression profiles and sensitivity database

    PubMed Central

    Gemma, Akihiko; Li, Cai; Sugiyama, Yuka; Matsuda, Kuniko; Seike, Yoko; Kosaihira, Seiji; Minegishi, Yuji; Noro, Rintaro; Nara, Michiya; Seike, Masahiro; Yoshimura, Akinobu; Shionoya, Aki; Kawakami, Akiko; Ogawa, Naoki; Uesaka, Haruka; Kudoh, Shoji

    2006-01-01

    background The effect of current therapies in improving the survival of lung cancer patients remains far from satisfactory. It is consequently desirable to find more appropriate therapeutic opportunities based on informed insights. A molecular pharmacological analysis was undertaken to design an improved chemotherapeutic strategy for advanced lung cancer. Methods We related the cytotoxic activity of each of commonly used anti-cancer agents (docetaxel, paclitaxel, gemcitabine, vinorelbine, 5-FU, SN38, cisplatin (CDDP), and carboplatin (CBDCA)) to corresponding expression pattern in each of the cell lines using a modified NCI program. Results We performed gene expression analysis in lung cancer cell lines using cDNA filter and high-density oligonucleotide arrays. We also examined the sensitivity of these cell lines to these drugs via MTT assay. To obtain our reproducible gene-drug sensitivity correlation data, we separately analyzed two sets of lung cancer cell lines, namely 10 and 19. In our gene-drug correlation analyses, gemcitabine consistently belonged to an isolated cluster in a reproducible fashion. On the other hand, docetaxel, paclitaxel, 5-FU, SN-38, CBDCA and CDDP were gathered together into one large cluster. Conclusion These results suggest that chemotherapy regimens including gemcitabine should be evaluated in second-line chemotherapy in cases where the first-line chemotherapy did not include this drug. Gene expression-drug sensitivity correlations, as provided by the NCI program, may yield improved therapeutic options for treatment of specific tumor types. PMID:16813650

  10. Lactate as a Novel Quantitative Measure of Viability in Schistosoma mansoni Drug Sensitivity Assays

    PubMed Central

    Howe, Stephanie; Zöphel, Dorina; Subbaraman, Harini; Unger, Clemens; Held, Jana; Engleitner, Thomas; Hoffmann, Wolfgang H.

    2014-01-01

    Whole-organism compound sensitivity assays are a valuable strategy in infectious diseases to identify active molecules. In schistosomiasis drug discovery, larval-stage Schistosoma allows the use of a certain degree of automation in the screening of compounds. Unfortunately, the throughput is limited, as drug activity is determined by manual assessment of Schistosoma viability by microscopy. To develop a simple and quantifiable surrogate marker for viability, we targeted glucose metabolism, which is central to Schistosoma survival. Lactate is the end product of glycolysis in human Schistosoma stages and can be detected in the supernatant. We assessed lactate as a surrogate marker for viability in Schistosoma drug screening assays. We thoroughly investigated parameters of lactate measurement and performed drug sensitivity assays by applying schistosomula and adult worms to establish a proof of concept. Lactate levels clearly reflected the viability of schistosomula and correlated with schistosomulum numbers. Compounds with reported potencies were tested, and activities were determined by lactate assay and by microscopy. We conclude that lactate is a sensitive and simple surrogate marker to be measured to determine Schistosoma viability in compound screening assays. Low numbers of schistosomula and the commercial availability of lactate assay reagents make the assay particularly attractive to throughput approaches. Furthermore, standardization of procedures and quantitative evaluation of compound activities facilitate interassay comparisons of potencies and, thus, concerted drug discovery approaches. PMID:25487803

  11. Malaria in South America: a drug discovery perspective

    PubMed Central

    2013-01-01

    The challenge of controlling and eventually eradicating malaria means that new tools are urgently needed. South America’s role in this fight spans both ends of the research and development spectrum: both as a continent capable of discovering and developing new medicines, and also as a continent with significant numbers of malaria patients. This article reviews the contribution of groups in the South American continent to the research and development of new medicines over the last decade. Therefore, the current situation of research targeting malaria control and eradication is discussed, including endemicity, geographical distribution, treatment, drug-resistance and diagnosis. This sets the scene for a review of efforts within South America to discover and optimize compounds with anti-malarial activity. PMID:23706107

  12. Drug procurement, the Global Fund and misguided competition policies.

    PubMed

    Tren, Richard; Hess, Kimberly; Bate, Roger

    2009-12-22

    In an effort to increase competition and decrease price, the Global Fund to Fight AIDS, Tuberculosis and Malaria recently began asking some grant recipients to use international competitive bidding processes for certain drug purchases. Unfortunately, for countries like Kenya, this request has caused more harm than good. After awarding the tender for its annual supply of the anti-malarial artemether-lumefantrine to the lowest bidder, Ajanta Pharma, Kenya experienced wide stock-outs in part due to the company's inability to supply the order in full and on time. Similar problems could arise in Uganda. Despite Kenya's experience, Uganda has awarded its next tender for artemether-lumefantrine to Ajanta Pharma. Uganda is already facing wide stock-outs and risks exacerbating an already dire situation the longer it takes to fulfil the procurement contract. A tender process based primarily on price cannot account for a company's ability to consistently supply sufficient product in time.

  13. A community effort to assess and improve drug sensitivity prediction algorithms

    PubMed Central

    Costello, James C; Heiser, Laura M; Georgii, Elisabeth; Gönen, Mehmet; Menden, Michael P; Wang, Nicholas J; Bansal, Mukesh; Ammad-ud-din, Muhammad; Hintsanen, Petteri; Khan, Suleiman A; Mpindi, John-Patrick; Kallioniemi, Olli; Honkela, Antti; Aittokallio, Tero; Wennerberg, Krister; Collins, James J; Gallahan, Dan; Singer, Dinah; Saez-Rodriguez, Julio; Kaski, Samuel; Gray, Joe W; Stolovitzky, Gustavo

    2015-01-01

    Predicting the best treatment strategy from genomic information is a core goal of precision medicine. Here we focus on predicting drug response based on a cohort of genomic, epigenomic and proteomic profiling data sets measured in human breast cancer cell lines. Through a collaborative effort between the National Cancer Institute (NCI) and the Dialogue on Reverse Engineering Assessment and Methods (DREAM) project, we analyzed a total of 44 drug sensitivity prediction algorithms. The top-performing approaches modeled nonlinear relationships and incorporated biological pathway information. We found that gene expression microarrays consistently provided the best predictive power of the individual profiling data sets; however, performance was increased by including multiple, independent data sets. We discuss the innovations underlying the top-performing methodology, Bayesian multitask MKL, and we provide detailed descriptions of all methods. This study establishes benchmarks for drug sensitivity prediction and identifies approaches that can be leveraged for the development of new methods. PMID:24880487

  14. Cellular Morphology-Mediated Proliferation and Drug Sensitivity of Breast Cancer Cells.

    PubMed

    Domura, Ryota; Sasaki, Rie; Ishikawa, Yuma; Okamoto, Masami

    2017-06-06

    The interpretation of the local microenvironment of the extracellular matrix for malignant tumor cells is in intimate relation with metastatic spread of cancer cells involving the associated issues of cellular proliferation and drug responsiveness. This study was aimed to assess the combination of both surface topographies (fiber alignments) and different stiffness of the polymeric substrates (poly(l-lactic acid) and poly(ε-caprolactone), PLLA and PCL, respectively) as well as collagen substrates (coat and gel) to elucidate the effect of the cellular morphology on cellular proliferation and drug sensitivities of two different types of breast cancer cells (MDA-MB-231 and MCF-7). The morphological spreading parameter (nucleus/cytoplasm area ratio) induced by the anthropogenic substrates has correlated intimately with the cellular proliferation and the drug sensitivity the half maximal inhibitory concentration (IC50) of cancer cells. This study demonstrated the promising results of the parameter for the evaluation of cancer cell malignancy.

  15. A community effort to assess and improve drug sensitivity prediction algorithms.

    PubMed

    Costello, James C; Heiser, Laura M; Georgii, Elisabeth; Gönen, Mehmet; Menden, Michael P; Wang, Nicholas J; Bansal, Mukesh; Ammad-ud-din, Muhammad; Hintsanen, Petteri; Khan, Suleiman A; Mpindi, John-Patrick; Kallioniemi, Olli; Honkela, Antti; Aittokallio, Tero; Wennerberg, Krister; Collins, James J; Gallahan, Dan; Singer, Dinah; Saez-Rodriguez, Julio; Kaski, Samuel; Gray, Joe W; Stolovitzky, Gustavo

    2014-12-01

    Predicting the best treatment strategy from genomic information is a core goal of precision medicine. Here we focus on predicting drug response based on a cohort of genomic, epigenomic and proteomic profiling data sets measured in human breast cancer cell lines. Through a collaborative effort between the National Cancer Institute (NCI) and the Dialogue on Reverse Engineering Assessment and Methods (DREAM) project, we analyzed a total of 44 drug sensitivity prediction algorithms. The top-performing approaches modeled nonlinear relationships and incorporated biological pathway information. We found that gene expression microarrays consistently provided the best predictive power of the individual profiling data sets; however, performance was increased by including multiple, independent data sets. We discuss the innovations underlying the top-performing methodology, Bayesian multitask MKL, and we provide detailed descriptions of all methods. This study establishes benchmarks for drug sensitivity prediction and identifies approaches that can be leveraged for the development of new methods.

  16. Synthesis and evaluation of sensitizer drug photorelease chemistry: Micro-optic method applied to singlet oxygen generation and drug delivery

    NASA Astrophysics Data System (ADS)

    Ghosh, Goutam

    This thesis summarizes a new micro-optic method for singlet oxygen generation and sensitizer drug delivery, which include i) synthesis and evaluation of a first generation device for drug delivery from native and fluorinated silica probe tips, ii) synthesis of PEG conjugated sensitizers to study phototoxicity in ovarian cancer cells, and iii) synthesis and evaluation of tris-PEGylated chlorin conjugated fluorinated silica for its future integration into the device to use as a 2nd generation device. A first generation micro-optic device was developed that works by sparging O2 gas and light generating cytotoxic singlet oxygen that cleaves the covalently attached drug (sensitizer) from the probe tip at the distal end of the fiber. The aim is to develop a 1st and 2nd generation device for site specific delivery of photosensitizer and singlet oxygen to overcome the challenges involved in systemic administration of the sensitizer. Synthesis and evaluation of drug (pheophorbide-a) delivery applying micro-optic method from native and fluorinated silica probe tip was achieved. The amount of sensitizer photocleavage depends on the loading level of sensitizer onto the probe tips. We also found that photorelease efficiency depends on the nature of the solvents where sensitizer is photocleaved. For example, no photorelease was observed in an aqueous solvent where sensitizer remained adsorbed to the native silica probe-tip. But, 90% photocleavage was obtained in octanol. A significant amount of photosensitizer (formate ester of pyropheophorbide- a) diffused into the liposome when photocleavage study was carried out in liposome. Substantial increase of photorelease was observed in organic solvent when pyropheophorbide-a (PPa) sensitizer was attached to the partially fluorinated porous Vycor glass. We also explored sensitizer photorelease from the fluorinated silica surface at various temperatures and we found that autocatalytic photorelease happened at room temperature and above

  17. Increased Replicative Fitness Can Lead to Decreased Drug Sensitivity of Hepatitis C Virus

    PubMed Central

    Sheldon, Julie; Beach, Nathan M.; Moreno, Elena; Gallego, Isabel; Piñeiro, David; Martínez-Salas, Encarnación; Gregori, Josep; Quer, Josep; Esteban, Juan Ignacio; Rice, Charles M.

    2014-01-01

    ABSTRACT Passage of hepatitis C virus (HCV) in human hepatoma cells resulted in populations that displayed partial resistance to alpha interferon (IFN-α), telaprevir, daclatasvir, cyclosporine, and ribavirin, despite no prior exposure to these drugs. Mutant spectrum analyses and kinetics of virus production in the absence and presence of drugs indicate that resistance is not due to the presence of drug resistance mutations in the mutant spectrum of the initial or passaged populations but to increased replicative fitness acquired during passage. Fitness increases did not alter host factors that lead to shutoff of general host cell protein synthesis and preferential translation of HCV RNA. The results imply that viral replicative fitness is a mechanism of multidrug resistance in HCV. IMPORTANCE Viral drug resistance is usually attributed to the presence of amino acid substitutions in the protein targeted by the drug. In the present study with HCV, we show that high viral replicative fitness can confer a general drug resistance phenotype to the virus. The results exclude the possibility that genomes with drug resistance mutations are responsible for the observed phenotype. The fact that replicative fitness can be a determinant of multidrug resistance may explain why the virus is less sensitive to drug treatments in prolonged chronic HCV infections that favor increases in replicative fitness. PMID:25122776

  18. Polypyrrole nanoparticles for tunable, pH-sensitive and sustained drug release

    NASA Astrophysics Data System (ADS)

    Samanta, Devleena; Meiser, Jana L.; Zare, Richard N.

    2015-05-01

    We report the development of a generalized pH-sensitive drug delivery system that can release any charged drug preferentially at the pH range of interest. Our system is based on polypyrrole nanoparticles (PPy NPs), synthesized via a simple one-step microemulsion technique. These nanoparticles are highly monodisperse, stable in solution over the period of a month, and have good drug loading capacity (~15 wt%). We show that PPy NPs can be tuned to release drugs at both acidic and basic pH by varying the pH, the charge of the drug, as well as by adding small amounts of charged amphiphiles. Moreover, these NPs may be delivered locally by immobilizing them in a hydrogel. Our studies show encapsulation within a calcium alginate hydrogel results in sustained release of the incorporated drug for more than 21 days. Such a nanoparticle-hydrogel composite drug delivery system is promising for treatment of long-lasting conditions such as cancer and chronic pain which require controlled, localized, and sustained drug release.

  19. Behavioral sensitization of the reinforcing value of food: What food and drugs have in common.

    PubMed

    Temple, Jennifer L

    2016-11-01

    Sensitization is a basic property of the nervous system whereby repeated exposure to a stimulus results in an increase in responding to that stimulus. This increase in responding contributes to difficulty with treatment of drug abuse, as stimuli associated with substance use become signals or triggers for drug craving and relapse. Our work over the past decade has applied the theoretical framework of incentive sensitization to overeating. We have shown, in several studies, that lean adults do not commonly demonstrate behavioral sensitization after repeated exposure to snack food, but a subset of obese adults reliably does. This review will discuss this change in behavioral response to repeated consumption of snack food in obese individuals and apply the theoretical framework of incentive sensitization to drugs of abuse to high fat/high sugar snack foods. We will also show data that suggest that behavioral sensitization to repeated administration of snack food is predictive of weight gain, which may enhance its utility as a diagnostic tool for identifying at-risk individuals for obesity. Finally, we will discuss the future directions of this line of research, including studying the phenomenon in children and adolescents and determining if similar principles can be used to increase motivation to eat healthier food. A combination of reductions in unhealthy food intake and increases and healthy food intake is necessary to reduce obesity rates and improve health. Copyright © 2016. Published by Elsevier Inc.

  20. One-step synthesis of interpenetrating network hydrogels: Environment sensitivities and drug delivery properties

    PubMed Central

    Lu, Jingqiong; Li, Yinhui; Hu, Deng; Chen, Xiaoling; Liu, Yongmei; Wang, Liping; Ashraf, Muhammmad Aqeel; Zhao, Yansheng

    2015-01-01

    A novel interpenetrating network hydrogel for drug controlled release, composed of modified poly(aspartic acid) (KPAsp) and carboxymethyl chitosan (CMCTS), was prepared in aqueous system. The surface morphology and composition of hydrogels were characterized by SEM and FTIR. The swelling properties of KPAsp, KPAsp/CMCTS semi-IPN and KPAsp/CMCTS IPN hydrogels were investigated and the swelling dynamics of the hydrogels was analyzed based on the Fickian equation. The pH, temperature and salt sensitivities of hydrogels were further studied, and the prepared hydrogels showed extremely sensitive properties to pH, temperature, the ionic salts kinds and concentration. The results of controlled drug release behaviors of the hydrogels revealed that the introduction of IPN observably improved the drug release properties of hydrogels, the release rate of drug from hydrogels can be controlled by the structure of the hydrogels and pH value of the external environment, a relative large amount of drug released was preferred under simulated intestinal fluid. These results illustrated high potential of the KPAsp/CMCTS IPN hydrogels for application as drug carriers. PMID:26858562

  1. pH sensitive coiled coils: a strategy for enhanced liposomal drug delivery

    NASA Astrophysics Data System (ADS)

    Reja, Rahi M.; Khan, Mohsina; Singh, Sumeet K.; Misra, Rajkumar; Shiras, Anjali; Gopi, Hosahudya N.

    2016-02-01

    Stimuli responsive controlled release from liposome based vesicles is a promising strategy for the site specific delivery of drugs. Herein, we report the design of pH sensitive coiled coils and their incorporation into the liposome as triggers for the controlled release of encapsulated drugs. The designed coiled coil peptides with the incorporation of environment sensitive fluorescent amino acids were found to be stable at physiological pH and unstructured while changing the pH of the environment to either acidic or basic. This pH dependent conformational switch of the coiled-coil polypeptides was exploited as triggers for the enhanced release of the encapsulated drug molecules from liposomes. The SEM, DLS and TEM analysis revealed the uniform morphology of the peptide liposome hybrid vesicles. Further, the drug encapsulated liposome internalization experiments with cancer cells revealed the enhanced release and accumulation of drugs in the acidic lysosomal compartments in comparison with liposomes without coiled coils.Stimuli responsive controlled release from liposome based vesicles is a promising strategy for the site specific delivery of drugs. Herein, we report the design of pH sensitive coiled coils and their incorporation into the liposome as triggers for the controlled release of encapsulated drugs. The designed coiled coil peptides with the incorporation of environment sensitive fluorescent amino acids were found to be stable at physiological pH and unstructured while changing the pH of the environment to either acidic or basic. This pH dependent conformational switch of the coiled-coil polypeptides was exploited as triggers for the enhanced release of the encapsulated drug molecules from liposomes. The SEM, DLS and TEM analysis revealed the uniform morphology of the peptide liposome hybrid vesicles. Further, the drug encapsulated liposome internalization experiments with cancer cells revealed the enhanced release and accumulation of drugs in the acidic

  2. [Bacterial culture and drug sensitivity analysis of upper urinary tract calculi complicating with infection].

    PubMed

    Wang, Shu; Shi, Yong-kang; Huang, Xiao-bo; Ma, Kai; Xu, Qing-quan; Xiong, Lin-lin; Li, Jian-xing; Wang, Xia-feng

    2014-10-18

    To investigate the bacteriology and drug sensitivity of upper urinary tract calculi patients, and to provide information for choosing suitable antibiotics. In the study, 21 patients who suffered from lithiasis in upper urinary tract and required an emergency drainage for acute obstruction and infection were the "acute group"; 64 patients with calculi in upper urinary tract and accompanied with no infectious symptoms were the "common group". The bacteriology and drug sensitivity of the two groups were investigated. Gram-negative bacteria infected the most common of upper urinary tract calculi patients with infection, accounting for 71.4% in the acute group and 65.7% in the common group, among which Escherichia coli were the predominant ones (35.7% in the acute group and 32.9% in the common group). No difference was found between these two groups in bacterial distribution (P>0.05). Although the average drug resistance rate of Gram-negative bacteria in the acute group was higher than that in the common group, it revealed no significant difference (P>0.05). The drug resistance rate to semisynthetic penicillin, cefuroxime and ceftriaxone were more than 50%, 60%, and 50%, respectively. Quinolones, such as ciprofloxacin and levofloxacin, got a 45% drug resistance. Aminoglycoside, carbapenema were sensitive to Gram-negative bacteria. Cefoperazone/sulbactam and piperacillin/tazobactam were more effective than ceftriaxone and piperacillin, respectively. There was no significant difference between upper urinary tract calculi patients with acute infection and common infection in bacteriology and drug sensitivity. Semisynthetic penicillin, the second generation of cephalosporin and quinolone were no longer the good choices of empirical use. Antibiotics combined with β-lactamase inhibitors would be an ideal empirical therapeutic choice.

  3. pH-sensitive, polymer modified, plasma stable niosomes: promising carriers for anti-cancer drugs

    PubMed Central

    Tila, Dena; Yazdani-Arazi, Seyede Narjes; Ghanbarzadeh, Saeed; Arami, Sanam; Pourmoazzen, Zhaleh

    2015-01-01

    The aim of this study was the design and evaluation of a novel plasma stable, pH-sensitive niosomal formulation of Mitoxantrone by a modified ethanol injection method. Cholesterol hemisuccinate was added instead of cholesterol in order to produce pH-sensitivity property and using PEG-Poly (monomethyl itaconate)-CholC6 (PEG-PMMI-CholC6) copolymer introduced simultaneously pH-sensitivity and plasma stability properties in prepared niosomes. The pH-sensitivity and cytotoxicity of Mitoxantrone niosomes were evaluated in vitro in phosphate buffer with different pHs as well as using human ovarian cancer cell line (OVCAR-3), human breast cancer cell line (MCF-7) and human umbilical vein endothelial cells (HUVEC). Results showed that both cholesterol derivatives bearing formulations had pH-sensitive property and were found to release their contents under mild acidic conditions rapidly. In addition, the PEG-PMMI-CholC6-based niosomes could reserve the pH-sensitivity after incubation in plasma. Both Mitoxantrone-loaded pH-sensitive niosomes showed higher cytotoxicity than the conventional niosomes on OVCAR-3 and MCF-7 cell lines. However, both pH-sensitive niosomes exhibited lower cytotoxic effect on HUVEC cell line. Plasma stable, pH-sensitive niosomes could improve the cytotoxic effect and reduce the side effects of anti-tumor drugs. PMID:26417350

  4. Salinomycin sensitizes antimitotic drugs-treated cancer cells by increasing apoptosis via the prevention of G2 arrest

    SciTech Connect

    Kim, Ju-Hwa; Yoo, Hye-In; Kang, Han Sung; Ro, Jungsil; Yoon, Sungpil

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Sal sensitizes antimitotic drugs-treated cancer cells. Black-Right-Pointing-Pointer Sal sensitizes them by prevention of G2 arrest and reduced cyclin D1 levels. Black-Right-Pointing-Pointer Sal also sensitizes them by increasing DNA damage and reducing p21 level. Black-Right-Pointing-Pointer A low concentration of Sal effectively sensitized the cancer cells to antimitotic drugs. -- Abstract: Here, we investigated whether Sal could sensitize cancer cells to antimitotic drugs. We demonstrated that Sal sensitized paclitaxcel (PAC)-, docetaxcel (DOC)-, vinblastin (VIN)-, or colchicine (COL)-treated cancer cell lines, suggesting that Sal has the ability to sensitize the cells to any form of microtubule-targeting drugs. Sensitization to the antimitotic drugs could be achieved with very low concentrations of Sal, suggesting that there is a possibility to minimize Sal toxicity associated with human cancer patient treatments. Sensitization by Sal increased apoptosis, which was observed by C-PARP production. Sal sensitized the cancer cells to antimitotic drugs by preventing G2 arrest, suggesting that Sal contributes to the induction of mitotic catastrophe. Sal generally reduced cyclin D1 levels in PAC-, DOC-, and VIN-treated cells. In addition, Sal treatment increased pH2AX levels and reduced p21 levels in antimitotic drugs-treated cells. These observations suggest that the mechanisms underlying Sal sensitization to DNA-damaging compounds, radiation, and microtubule-targeting drugs are similar. Our data demonstrated that Sal sensitizes cancer cells to antimitotic drugs by increasing apoptosis through the prevention of G2 arrest via conserved Sal-sensitization mechanisms. These results may contribute to the development of Sal-based chemotherapy for cancer patients treated with antimitotic drugs.

  5. Genetic diversity and drug sensitivity studies on Eimeria tenella field isolates from Hubei Province of China.

    PubMed

    Tan, Li; Li, Yalin; Yang, Xin; Ke, Qiyun; Lei, Weiqiang; Mughal, Mudassar Niaz; Fang, Rui; Zhou, Yanqin; Shen, Bang; Zhao, Junlong

    2017-03-09

    Avian coccidiosis is an intracellular intestinal parasitic disease, caused by intracellular intestinal parasites from the genus Eimeria, among which Eimeria tenella is one of the most pathogenic species and causes great economic losses. Frequent applications of anticoccidial drugs have resulted in the development of drug-resistance in E. tenella. In the present study, we sought to determine the genetic diversity of E. tenella isolates prevalent in chicken farms in Hubei Province of China and examine their sensitivity to three anticoccidial drugs. The results provide useful information for the prevention and control of coccidiosis in this region. Eimeria tenella oocysts were isolated from faecal samples collected from different commercial broiler production farms in Hubei Province, China. After oocyst sporulation and animal inoculation for expansion of the field isolates, DNA and RNA were extracted from excysted sporozoites for molecular characterization. Species identification of field isolates were performed by polymerase chain reaction (PCR) amplification of the internal transcribed spacer 1 (ITS1) region of ribosomal DNA. Random amplified polymorphic DNA (RAPD) was used for population genetic analysis. Subsequently, sequences of the major sporozoite surface antigen (SAG), micronemal protein 2 (MIC-2) and cytochrome b (cytb) genes from genomic DNA, and the Eimeria tenella cation-transport ATPase (EtCat ATPase) gene from cDNA were obtained for genotyping using multi-sequence alignments. Finally, sensitivity of the field isolates to three commonly used anticoccidial drugs (diclazuril, decoquinate and maduramycin) were tested to assess the prevalence of drug resistance in E. tenella in Hubei Province of China. Analysis of the ITS1 sequences indicated that all the isolates were E. tenella. RAPD analysis and multi-sequence alignments of the SAG, MIC-2, EtCat ATPase and cytb showed genetic diversity among these isolates. Finally, drug sensitivity tests demonstrated

  6. Metabolic glycoengineering sensitizes drug-resistant pancreatic cancer cells to tyrosine kinase inhibitors erlotinib and gefitinib.

    PubMed

    Mathew, Mohit P; Tan, Elaine; Saeui, Christopher T; Bovonratwet, Patawut; Liu, Lingshu; Bhattacharya, Rahul; Yarema, Kevin J

    2015-03-15

    Metastatic human pancreatic cancer cells (the SW1990 line) that are resistant to the EGFR-targeting tyrosine kinase inhibitor drugs (TKI) erlotinib and gefitinib were treated with 1,3,4-O-Bu3ManNAc, a 'metabolic glycoengineering' drug candidate that increased sialylation by ∼2-fold. Consistent with genetic methods previously used to increase EGFR sialylation, this small molecule reduced EGF binding, EGFR transphosphorylation, and downstream STAT activation. Significantly, co-treatment with both the sugar pharmacophore and the existing TKI drugs resulted in strong synergy, in essence re-sensitizing the SW1990 cells to these drugs. Finally, 1,3,4-O-Bu3ManNAz, which is the azido-modified counterpart to 1,3,4-O-Bu3ManNAc, provided a similar benefit thereby establishing a broad-based foundation to extend a 'metabolic glycoengineering' approach to clinical applications.

  7. Role of pressure-sensitive adhesives in transdermal drug delivery systems.

    PubMed

    Lobo, Shabbir; Sachdeva, Sameer; Goswami, Tarun

    2016-01-01

    Transdermal drug delivery systems (TDDS) are employed for the delivery of drugs across skin into the systemic circulation. Pressure-sensitive adhesive (PSA) is one of the most critical components used in a TDDS. The primary function of PSA is to help in adhesion of patch to skin, but more importantly it acts as a matrix for the drug and other excipients. Hence, apart from adhesion of the patch, PSA also affects other critical quality attributes of the TDDS such as drug delivery, flux through skin and physical and chemical stability of the finished product. This review article provides a summary of the adhesives used in various types of TDDS. In particular, this review will cover the design types of TDDS, categories of PSAs and their evaluation and regulatory aspects.

  8. Drug-resistant malaria in Sudan: A review of evidence and scenarios for the future

    PubMed Central

    2012-01-01

    Resistance of falciparum malaria to chloroquine (CQ) has gradually emerged in the late 1970s, reaching unacceptably high proportions over the following three decades of use as frst line treatment in Sudan. By 2004–2006 CQ was replaced by artemisinin-based combination treatment (ACTs), with combination of sulfadoxine-pyrimethamine (SP) and artesunate (AS) deployed as frst-line drug against falciparum malaria. The present review follows the evolution of CQ resistance in Sudan and the available evidence on the response to the present frst-line drugs. The fndings in Sudan are analyzed in view of developments in other African countries and at the global level, with the hope of elucidating possible scenarios for the course of events in the Sudan. Northern Sudan has been one of the areas where signals indicating the emergence of drug resistant malaria parasites have frst originated in Africa. The pattern of low endemicity and low population immunity to malaria, together with massive deployment and improper use of anti-malarial drugs created the ideal environment for creation of anti-malarial drug resistance. Such an environment existed in certain areas in South East Asia that had historically been the epicenter from which falciparum malaria parasites resistant to pyrimethamine and chloroquine have spread to the rest of the world. The alarming recent reports about the emergence of artemisinin (ART) resistance in South East Asia have lead WHO to take specifc measures for prevention, early detection and containment of drug resistance. What could be applicable in Sudan in these measures is discussed here. PMID:27493325

  9. Variability in initial nicotine sensitivity due to sex, history of other drug use, and parental smoking.

    PubMed

    Perkins, Kenneth A; Coddington, Sarah B; Karelitz, Joshua L; Jetton, Christopher; Scott, John A; Wilson, Annette S; Lerman, Caryn

    2009-01-01

    Initial sensitivity to nicotine's effects during early exposure to tobacco may relate to dependence vulnerability. We examined the association of initial nicotine sensitivity with individual difference factors of sex, other drug use history (i.e. cross-tolerance or cross-sensitization), and parental smoking status in young adult nonsmokers (N=131). Participants engaged in 4 sessions, the first 3 to assess the dose-response effects of nasal spray nicotine (0, 5, 10 microg/kg) on rewarding, mood, physiological, sensory processing, and performance effects, and the fourth to assess nicotine reinforcement using a choice procedure. Men had greater initial sensitivity than women to some self-reported effects of nicotine related to reward and incentive salience and to impairment in sensory processing, but men and women did not differ on most other effects. Prior marijuana use was associated with greater nicotine reward, nicotine reinforcement was greater in men versus women among those with prior marijuana use, and having parents who smoked was related to increased incentive salience. However, history of other drug use and parental smoking were not otherwise associated with initial nicotine sensitivity. These findings warrant replication with other methods of nicotine administration, especially cigarette smoking, and in more diverse samples of subjects naïve to nicotine. Yet, they suggest that sex differences in initial sensitivity to nicotine reward occur before the onset of dependence. They also suggest that parental smoking may not increase risk of nicotine dependence in offspring by altering initial nicotine sensitivity, and that cross-tolerance between other drugs and nicotine may not be robust in humans.

  10. Modulating cell-to-cell variability and sensitivity to death ligands by co-drugging

    NASA Astrophysics Data System (ADS)

    Flusberg, Deborah A.; Sorger, Peter K.

    2013-06-01

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) holds promise as an anti-cancer therapeutic but efficiently induces apoptosis in only a subset of tumor cell lines. Moreover, even in clonal populations of responsive lines, only a fraction of cells dies in response to TRAIL and individual cells exhibit cell-to-cell variability in the timing of cell death. Fractional killing in these cell populations appears to arise not from genetic differences among cells but rather from differences in gene expression states, fluctuations in protein levels and the extent to which TRAIL-induced death or survival pathways become activated. In this study, we ask how cell-to-cell variability manifests in cell types with different sensitivities to TRAIL, as well as how it changes when cells are exposed to combinations of drugs. We show that individual cells that survive treatment with TRAIL can regenerate the sensitivity and death-time distribution of the parental population, demonstrating that fractional killing is a stable property of cell populations. We also show that cell-to-cell variability in the timing and probability of apoptosis in response to treatment can be tuned using combinations of drugs that together increase apoptotic sensitivity compared to treatment with one drug alone. In the case of TRAIL, modulation of cell-to-cell variability by co-drugging appears to involve a reduction in the threshold for mitochondrial outer membrane permeabilization.

  11. Dynamical Model of Drug Accumulation in Bacteria: Sensitivity Analysis and Experimentally Testable Predictions

    PubMed Central

    Vesselinova, Neda; Wall, Michael E.

    2016-01-01

    We present a dynamical model of drug accumulation in bacteria. The model captures key features in experimental time courses on ofloxacin accumulation: initial uptake; two-phase response; and long-term acclimation. In combination with experimental data, the model provides estimates of import and export rates in each phase, the time of entry into the second phase, and the decrease of internal drug during acclimation. Global sensitivity analysis, local sensitivity analysis, and Bayesian sensitivity analysis of the model provide information about the robustness of these estimates, and about the relative importance of different parameters in determining the features of the accumulation time courses in three different bacterial species: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The results lead to experimentally testable predictions of the effects of membrane permeability, drug efflux and trapping (e.g., by DNA binding) on drug accumulation. A key prediction is that a sudden increase in ofloxacin accumulation in both E. coli and S. aureus is accompanied by a decrease in membrane permeability. PMID:27824914

  12. Quantitative scoring of differential drug sensitivity for individually optimized anticancer therapies

    PubMed Central

    Yadav, Bhagwan; Pemovska, Tea; Szwajda, Agnieszka; Kulesskiy, Evgeny; Kontro, Mika; Karjalainen, Riikka; Majumder, Muntasir Mamun; Malani, Disha; Murumägi, Astrid; Knowles, Jonathan; Porkka, Kimmo; Heckman, Caroline; Kallioniemi, Olli; Wennerberg, Krister; Aittokallio, Tero

    2014-01-01

    We developed a systematic algorithmic solution for quantitative drug sensitivity scoring (DSS), based on continuous modeling and integration of multiple dose-response relationships in high-throughput compound testing studies. Mathematical model estimation and continuous interpolation makes the scoring approach robust against sources of technical variability and widely applicable to various experimental settings, both in cancer cell line models and primary patient-derived cells. Here, we demonstrate its improved performance over other response parameters especially in a leukemia patient case study, where differential DSS between patient and control cells enabled identification of both cancer-selective drugs and drug-sensitive patient sub-groups, as well as dynamic monitoring of the response patterns and oncogenic driver signals during cancer progression and relapse in individual patient cells ex vivo. An open-source and easily extendable implementation of the DSS calculation is made freely available to support its tailored application to translating drug sensitivity testing results into clinically actionable treatment options. PMID:24898935

  13. Dynamical Model of Drug Accumulation in Bacteria: Sensitivity Analysis and Experimentally Testable Predictions

    DOE PAGES

    Vesselinova, Neda; Alexandrov, Boian; Wall, Michael E.

    2016-11-08

    We present a dynamical model of drug accumulation in bacteria. The model captures key features in experimental time courses on ofloxacin accumulation: initial uptake; two-phase response; and long-term acclimation. In combination with experimental data, the model provides estimates of import and export rates in each phase, the time of entry into the second phase, and the decrease of internal drug during acclimation. Global sensitivity analysis, local sensitivity analysis, and Bayesian sensitivity analysis of the model provide information about the robustness of these estimates, and about the relative importance of different parameters in determining the features of the accumulation time coursesmore » in three different bacterial species: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The results lead to experimentally testable predictions of the effects of membrane permeability, drug efflux and trapping (e.g., by DNA binding) on drug accumulation. A key prediction is that a sudden increase in ofloxacin accumulation in both E. coli and S. aureus is accompanied by a decrease in membrane permeability.« less

  14. Copper transporters regulate the cellular pharmacology and sensitivity to Pt drugs.

    PubMed

    Safaei, Roohangiz; Howell, Stephen B

    2005-01-01

    Recent studies have demonstrated that the major Cu influx transporter CTR1 regulates tumor cell uptake of cisplatin (DDP), carboplatin (CBDCA) and oxaliplatin (L-OHP), and that the two Cu efflux transporters ATP7A and ATP7B regulate the efflux of these drugs. Evidence for the concept that these platinum (Pt) drugs enter cells and are distributed to various subcellular compartments via transporters that have evolved to manage Cu homeostasis includes the demonstration of: (1) bidirectional cross-resistance between cells selected for resistance to either the Pt drugs or Cu; (2) parallel changes in the transport of Pt and Cu drugs in resistant cells; (3) altered cytotoxic sensitivity and Pt drug accumulation in cells transfected with Cu transporters; and (4) altered expression of Cu transporters in Pt drug-resistant tumors. Appreciation of the role of the Cu transporters in the development of resistance to DDP, CBDCA, and L-OHP offers novel insights into strategies for preventing or reversing resistance to this very important family of anticancer drugs.

  15. Thermo-sensitive complex micelles from sodium alginate-graft-poly(N-isopropylacrylamide) for drug release.

    PubMed

    Yu, Nana; Li, Guiying; Gao, Yurong; Jiang, Hua; Tao, Qian

    2016-05-01

    Polymer micelles with environmentally sensitive properties have potential applications in biomedicine. In this paper, thermo-sensitive complex micelles assembled from biocompatible graft copolymers sodium alginate-graft-poly(N-isopropylacrylamide) (SA-g-PNIPAM) and divalent metal ions were prepared for controlled drug release. The polymer micelles had core-corona structure, which was constituted by metal ions (Ba(2+), Zn(2+), Co(2+)) cross-linked sodium alginate as the core and thermo-sensitive PNIPAM chains as the corona. Formation of polymer micelles was determined by Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The polymer micelles were observed as regular spheres with good polydispersity and excellent performance on drug encapsulation and release ability. The cumulative release of 5-fluorouracil (5-FU) from micelles was controlled by pH, ionic strength or temperature of surroundings. The superior properties of sensitive polymer micelles induced by metal ions are expected to be utilized in controlled drug delivery systems.

  16. Rapid Sensitization of Physiological, Neuronal, and Locomotor Effects of Nicotine: Critical Role of Peripheral Drug Actions

    PubMed Central

    Lenoir, Magalie; Tang, Jeremy S.; Woods, Amina S.

    2013-01-01

    Repeated exposure to nicotine and other psychostimulant drugs produces persistent increases in their psychomotor and physiological effects (sensitization), a phenomenon related to the drugs' reinforcing properties and abuse potential. Here we examined the role of peripheral actions of nicotine in nicotine-induced sensitization of centrally mediated physiological parameters (brain, muscle, and skin temperatures), cortical and VTA EEG, neck EMG activity, and locomotion in freely moving rats. Repeated injections of intravenous nicotine (30 μg/kg) induced sensitization of the drug's effects on all these measures. In contrast, repeated injections of the peripherally acting analog of nicotine, nicotine pyrrolidine methiodide (nicotinePM, 30 μg/kg, i.v.) resulted in habituation (tolerance) of the same physiological, neuronal, and behavioral measures. However, after repeated nicotine exposure, acute nicotinePM injections induced nicotine-like physiological responses: powerful cortical and VTA EEG desynchronization, EMG activation, a large brain temperature increase, but weaker hyperlocomotion. Additionally, both the acute locomotor response to nicotine and nicotine-induced locomotor sensitization were attenuated by blockade of peripheral nicotinic receptors by hexamethonium (3 mg/kg, i.v.). These data suggest that the peripheral actions of nicotine, which precede its direct central actions, serve as a conditioned interoceptive cue capable of eliciting nicotine-like physiological and neural responses after repeated nicotine exposure. Thus, by providing a neural signal to the CNS that is repeatedly paired with the direct central effects of nicotine, the drug's peripheral actions play a critical role in the development of nicotine-induced physiological, neural, and behavioral sensitization. PMID:23761889

  17. Validation of a sample pretreatment protocol to convert a drug-sensitive into a drug-tolerant anti-infliximab antibody immunoassay.

    PubMed

    Van Stappen, Thomas; Brouwers, Els; Vermeire, Séverine; Gils, Ann

    2017-02-01

    A meta-analysis revealed that up to 51% of patients treated with infliximab develop anti-drug Abs (ADA) which are associated with loss of response. Detection of ADA is strongly influenced by assay technique since drug-sensitive ADA assays are not able to detect ADA in the presence of drug and therefore underestimate ADA development. In addition, the lack of a calibrator antibody that can be used in a drug-sensitive and drug-tolerant assay hampers an adequate comparison among different assays. Here we present a sample pretreatment protocol to convert the bridging assay, originally developed as a drug-sensitive assay, into a drug-tolerant assay, allowing use of the same assay and calibrator antibody MA-IFX10F9. Using the sample pretreatment protocol, the bridging assay detects antibodies towards infliximab in samples containing up to 5-fold infliximab over anti-infliximab. Analysis of consecutive serum samples from infliximab treated patients revealed that the drug-tolerant assay detects ADA development up to 40 weeks earlier compared to the drug-sensitive assay. In conclusion, the sample pretreatment protocol can be implemented in various assay formats and allows determination of ADA in the presence of drug, providing the possibility for early treatment optimization. Copyright © 2016 John Wiley & Sons, Ltd.

  18. pH-sensitive polymeric nanoparticles to improve oral bioavailability of peptide/protein drugs and poorly water-soluble drugs.

    PubMed

    Wang, Xue-Qing; Zhang, Qiang

    2012-10-01

    pH-sensitive polymeric nanoparticles are promising for oral drug delivery, especially for peptide/protein drugs and poorly water-soluble medicines. This review describes current status of pH-sensitive polymeric nanoparticles for oral drug delivery and introduces the mechanisms of drug release from them as well as possible reasons for absorption improvement, with emphasis on our contribution to this field. pH-sensitive polymeric nanoparticles are prepared mainly with polyanions, polycations, their mixtures or cross-linked polymers. The mechanisms of drug release are the result of carriers' dissolution, swelling or both of them at specific pH. The possible reasons for improvement of oral bioavailability include the following: improve drug stability, enhance mucoadhesion, prolong resident time in GI tract, ameliorate intestinal permeability and increase saturation solubility and dissolution rate for poorly water-soluble drugs. As for the advantages of pH-sensitive nanoparticles over conventional nanoparticles, we conclude that (1) most carriers used are enteric-coating materials and their safety has been approved. (2) The rapid dissolution or swelling of carriers at specific pH results in quick drug release and high drug concentration gradient, which is helpful for absorption. (3) At the specific pH carriers dissolve or swell, and the bioadhesion of carriers to mucosa becomes high because nanoparticles turn from solid to gel, which can facilitate drug absorption.

  19. Discovery of New Monocarbonyl Ligustrazine-Curcumin Hybrids for Intervention of Drug-Sensitive and Drug-Resistant Lung Cancer.

    PubMed

    Ai, Yong; Zhu, Bin; Ren, Caiping; Kang, Fenghua; Li, Jinlong; Huang, Zhangjian; Lai, Yisheng; Peng, Sixun; Ding, Ke; Tian, Jide; Zhang, Yihua

    2016-03-10

    The elevation of oxidative stress preferentially in cancer cells by inhibiting thioredoxin reductase (TrxR) and/or enhancing reactive oxygen species (ROS) production has emerged as an effective strategy for selectively targeting cancer cells. In this study, we designed and synthesized 21 ligustrazine-curcumin hybrids (10a-u). Biological evaluation indicated that the most active compound 10d significantly inhibited the proliferation of drug-sensitive (A549, SPC-A-1, LTEP-G-2) and drug-resistant (A549/DDP) lung cancer cells but had little effect on nontumor lung epithelial-like cells (HBE). Furthermore, 10d suppressed the TrxR/Trx system and promoted intracellular ROS accumulation and cancer cell apoptosis. Additionally, 10d inhibited the NF-κB, AKT, and ERK signaling, P-gp-mediated efflux of rhodamine 123, P-gp ATPase activity, and P-gp expression in A549/DDP cells. Finally, 10d repressed the growth of implanted human drug-resistant lung cancer in mice. Together, 10d acts a novel TrxR inhibitor and may be a promising candidate for intervention of lung cancer.

  20. Variation in topoisomerase I gene copy number as a mechanism for intrinsic drug sensitivity.

    PubMed Central

    McLeod, H. L.; Keith, W. N.

    1996-01-01

    DNA topoisomerase I (topo I) is the principle target for camptothecin and its derivatives such as SN38. Levels of topo I expression vary widely between and within tumour types and the basis for this is poorly understood. We have used fluorescence in situ hybridisation to detect the topo I locus in a panel of breast and colon cancer cell lines. This approach has identified a range of topo I gene copies from 1 to 6 between the cell lines as a result of DNA amplification, polysomy and isochromosome formation. Topo I gene copy number was highly correlated with topo I expression, (rs = 0.92), and inversely correlated to sensitivity to a 1 h exposure to SN38 (rs = -0.904). This illustrates the significant impact of altered topo I gene copy number on intrinsic drug sensitivity and influences potential mechanisms for acquisition of drug resistance. Images Figure 1 Figure 2 PMID:8761363

  1. Discovery of novel drug sensitivities in T-PLL by high-throughput ex vivo drug testing and mutation profiling.

    PubMed

    Andersson, E I; Pützer, S; Yadav, B; Dufva, O; Khan, S; He, L; Sellner, L; Schrader, A; Crispatzu, G; Oleś, M; Zhang, H; Adnan-Awad, S; Lagström, S; Bellanger, D; Mpindi, J P; Eldfors, S; Pemovska, T; Pietarinen, P; Lauhio, A; Tomska, K; Cuesta-Mateos, C; Faber, E; Koschmieder, S; Brümmendorf, T H; Kytölä, S; Savolainen, E-R; Siitonen, T; Ellonen, P; Kallioniemi, O; Wennerberg, K; Ding, W; Stern, M-H; Huber, W; Anders, S; Tang, J; Aittokallio, T; Zenz, T; Herling, M; Mustjoki, S

    2017-08-14

    T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive neoplasm of mature T-cells with an urgent need for rationally designed therapies to address its notoriously chemo-refractory behavior. The median survival of T-PLL patients is <2 years and clinical trials are difficult to execute. Here we systematically explored the diversity of drug responses in T-PLL patient samples using an ex vivo drug sensitivity and resistance testing platform and correlated the findings with somatic mutations and gene expression profiles. Intriguingly, all T-PLL samples were sensitive to the cyclin-dependent kinase inhibitor SNS-032, which overcame stromal-cell-mediated protection and elicited robust p53-activation and apoptosis. Across all patients, the most effective classes of compounds were histone deacetylase, phosphoinositide-3 kinase/AKT/mammalian target of rapamycin, heat-shock protein 90 and BH3-family protein inhibitors as well as p53 activators, indicating previously unexplored, novel targeted approaches for treating T-PLL. Although Janus-activated kinase-signal transducer and activator of transcription factor (JAK-STAT) pathway mutations were common in T-PLL (71% of patients), JAK-STAT inhibitor responses were not directly linked to those or other T-PLL-specific lesions. Overall, we found that genetic markers do not readily translate into novel effective therapeutic vulnerabilities. In conclusion, novel classes of compounds with high efficacy in T-PLL were discovered with the comprehensive ex vivo drug screening platform warranting further studies of synergisms and clinical testing.Leukemia advance online publication, 1 September 2017; doi:10.1038/leu.2017.252.

  2. Genome-wide barcoded transposon screen for cancer drug sensitivity in haploid mouse embryonic stem cells

    PubMed Central

    Pettitt, Stephen J.; Krastev, Dragomir B.; Pemberton, Helen N.; Fontebasso, Yari; Frankum, Jessica; Rehman, Farah L.; Brough, Rachel; Song, Feifei; Bajrami, Ilirjana; Rafiq, Rumana; Wallberg, Fredrik; Kozarewa, Iwanka; Fenwick, Kerry; Armisen-Garrido, Javier; Swain, Amanda; Gulati, Aditi; Campbell, James; Ashworth, Alan; Lord, Christopher J.

    2017-01-01

    We describe a screen for cellular response to drugs that makes use of haploid embryonic stem cells. We generated ten libraries of mutants with piggyBac gene trap transposon integrations, totalling approximately 100,000 mutant clones. Random barcode sequences were inserted into the transposon vector to allow the number of cells bearing each insertion to be measured by amplifying and sequencing the barcodes. These barcodes were associated with their integration sites by inverse PCR. We exposed these libraries to commonly used cancer drugs and profiled changes in barcode abundance by Ion Torrent sequencing in order to identify mutations that conferred sensitivity. Drugs tested included conventional chemotherapeutics as well as targeted inhibitors of topoisomerases, poly(ADP-ribose) polymerase (PARP), Hsp90 and WEE1. PMID:28248920

  3. The Cancer Cell Line Encyclopedia enables predictive modelling of anticancer drug sensitivity.

    PubMed

    Barretina, Jordi; Caponigro, Giordano; Stransky, Nicolas; Venkatesan, Kavitha; Margolin, Adam A; Kim, Sungjoon; Wilson, Christopher J; Lehár, Joseph; Kryukov, Gregory V; Sonkin, Dmitriy; Reddy, Anupama; Liu, Manway; Murray, Lauren; Berger, Michael F; Monahan, John E; Morais, Paula; Meltzer, Jodi; Korejwa, Adam; Jané-Valbuena, Judit; Mapa, Felipa A; Thibault, Joseph; Bric-Furlong, Eva; Raman, Pichai; Shipway, Aaron; Engels, Ingo H; Cheng, Jill; Yu, Guoying K; Yu, Jianjun; Aspesi, Peter; de Silva, Melanie; Jagtap, Kalpana; Jones, Michael D; Wang, Li; Hatton, Charles; Palescandolo, Emanuele; Gupta, Supriya; Mahan, Scott; Sougnez, Carrie; Onofrio, Robert C; Liefeld, Ted; MacConaill, Laura; Winckler, Wendy; Reich, Michael; Li, Nanxin; Mesirov, Jill P; Gabriel, Stacey B; Getz, Gad; Ardlie, Kristin; Chan, Vivien; Myer, Vic E; Weber, Barbara L; Porter, Jeff; Warmuth, Markus; Finan, Peter; Harris, Jennifer L; Meyerson, Matthew; Golub, Todd R; Morrissey, Michael P; Sellers, William R; Schlegel, Robert; Garraway, Levi A

    2012-03-28

    The systematic translation of cancer genomic data into knowledge of tumour biology and therapeutic possibilities remains challenging. Such efforts should be greatly aided by robust preclinical model systems that reflect the genomic diversity of human cancers and for which detailed genetic and pharmacological annotation is available. Here we describe the Cancer Cell Line Encyclopedia (CCLE): a compilation of gene expression, chromosomal copy number and massively parallel sequencing data from 947 human cancer cell lines. When coupled with pharmacological profiles for 24 anticancer drugs across 479 of the cell lines, this collection allowed identification of genetic, lineage, and gene-expression-based predictors of drug sensitivity. In addition to known predictors, we found that plasma cell lineage correlated with sensitivity to IGF1 receptor inhibitors; AHR expression was associated with MEK inhibitor efficacy in NRAS-mutant lines; and SLFN11 expression predicted sensitivity to topoisomerase inhibitors. Together, our results indicate that large, annotated cell-line collections may help to enable preclinical stratification schemata for anticancer agents. The generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of 'personalized' therapeutic regimens.

  4. The Cancer Cell Line Encyclopedia enables predictive modeling of anticancer drug sensitivity

    PubMed Central

    Barretina, Jordi; Caponigro, Giordano; Stransky, Nicolas; Venkatesan, Kavitha; Margolin, Adam A.; Kim, Sungjoon; Wilson, Christopher J.; Lehár, Joseph; Kryukov, Gregory V.; Sonkin, Dmitriy; Reddy, Anupama; Liu, Manway; Murray, Lauren; Berger, Michael F.; Monahan, John E.; Morais, Paula; Meltzer, Jodi; Korejwa, Adam; Jané-Valbuena, Judit; Mapa, Felipa A.; Thibault, Joseph; Bric-Furlong, Eva; Raman, Pichai; Shipway, Aaron; Engels, Ingo H.; Cheng, Jill; Yu, Guoying K.; Yu, Jianjun; Aspesi, Peter; de Silva, Melanie; Jagtap, Kalpana; Jones, Michael D.; Wang, Li; Hatton, Charles; Palescandolo, Emanuele; Gupta, Supriya; Mahan, Scott; Sougnez, Carrie; Onofrio, Robert C.; Liefeld, Ted; MacConaill, Laura; Winckler, Wendy; Reich, Michael; Li, Nanxin; Mesirov, Jill P.; Gabriel, Stacey B.; Getz, Gad; Ardlie, Kristin; Chan, Vivien; Myer, Vic E.; Weber, Barbara L.; Porter, Jeff; Warmuth, Markus; Finan, Peter; Harris, Jennifer L.; Meyerson, Matthew; Golub, Todd R.; Morrissey, Michael P.; Sellers, William R.; Schlegel, Robert; Garraway, Levi A.

    2012-01-01

    The systematic translation of cancer genomic data into knowledge of tumor biology and therapeutic avenues remains challenging. Such efforts should be greatly aided by robust preclinical model systems that reflect the genomic diversity of human cancers and for which detailed genetic and pharmacologic annotation is available1. Here we describe the Cancer Cell Line Encyclopedia (CCLE): a compilation of gene expression, chromosomal copy number, and massively parallel sequencing data from 947 human cancer cell lines. When coupled with pharmacologic profiles for 24 anticancer drugs across 479 of the lines, this collection allowed identification of genetic, lineage, and gene expression-based predictors of drug sensitivity. In addition to known predictors, we found that plasma cell lineage correlated with sensitivity to IGF1 receptor inhibitors; AHR expression was associated with MEK inhibitor efficacy in NRAS-mutant lines; and SLFN11 expression predicted sensitivity to topoisomerase inhibitors. Altogether, our results suggest that large, annotated cell line collections may help to enable preclinical stratification schemata for anticancer agents. The generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of “personalized” therapeutic regimens2. PMID:22460905

  5. Enhancement of drug sensitivity of human malignancies by epidermal growth factor.

    PubMed Central

    Kröning, R.; Jones, J. A.; Hom, D. K.; Chuang, C. C.; Sanga, R.; Los, G.; Howell, S. B.; Christen, R. D.

    1995-01-01

    We have previously shown that epidermal growth factor (EGF) enhances the in vitro and in vivo sensitivity of human ovarian carcinoma 2008 cells to cisplatin. EGF was found to enhance selectively the in vivo toxicity of cisplatin to 2008 cell xenografts without altering the toxicity of cisplatin to non-malignant target tissues such as the kidney or bone marrow. We now show that recombinant human EGF (rhEGF) enhances the cisplatin sensitivity of cell lines representative of many other types of malignancies in addition to ovarian carcinoma, including cancers of the head and neck, cervix, colon, pancreas and prostate, as well as non-small-cell carcinoma of the lung. In addition, rhEGF was found to sensitise cells to other platinum-containing drugs and several other classes of chemotherapeutic agents. rhEGF sensitised 2008 cells not only to cisplatin, but also to carboplatin and tetraplatin, as well as taxol, melphalan and 5-fluorouracil. We conclude that modulation of drug sensitivity by rhEGF is observed in cell lines representative of many human malignancies and for multiple classes of chemotherapeutic agents, indicating that it alters one or more components of the cellular damage response that are both common between cell lines and classes of drugs and fundamental to survival. Images Figure 2 PMID:7669570

  6. Systematic identification of genomic markers of drug sensitivity in cancer cells

    PubMed Central

    Garnett, Mathew J.; Edelman, Elena J.; Heidorn, Sonja J.; Greenman, Chris D.; Dastur, Anahita; Lau, King Wai; Greninger, Patricia; Thompson, I. Richard; Luo, Xi; Soares, Jorge; Liu, Qingsong; Iorio, Francesco; Surdez, Didier; Chen, Li; Milano, Randy J.; Bignell, Graham R.; Tam, Ah T.; Davies, Helen; Stevenson, Jesse A.; Barthorpe, Syd; Lutz, Stephen R.; Kogera, Fiona; Lawrence, Karl; McLaren-Douglas, Anne; Mitropoulos, Xeni; Mironenko, Tatiana; Thi, Helen; Richardson, Laura; Zhou, Wenjun; Jewitt, Frances; Zhang, Tinghu; O’Brien, Patrick; Boisvert, Jessica L.; Price, Stacey; Hur, Wooyoung; Yang, Wanjuan; Deng, Xianming; Butler, Adam; Choi, Hwan Geun; Chang, Jae Won; Baselga, Jose; Stamenkovic, Ivan; Engelman, Jeffrey A.; Sharma, Sreenath V.; Delattre, Olivier; Saez-Rodriguez, Julio; Gray, Nathanael S.; Settleman, Jeffrey; Futreal, P. Andrew; Haber, Daniel A.; Stratton, Michael R.; Ramaswamy, Sridhar; McDermott, Ultan; Benes, Cyril H.

    2012-01-01

    Clinical responses to anticancer therapies are often restricted to a subset of patients. In some cases, mutated cancer genes are potent biomarkers of response to targeted agents. To uncover new biomarkers of sensitivity and resistance to cancer therapeutics, we screened a panel of several hundred cancer cell lines, which represent much of the tissue-type and genetic diversity of human cancers, with 130 drugs under clinical and preclinical investigation. In aggregate, we found mutated cancer genes were associated with cellular response to most currently available cancer drugs. Classic oncogene addiction paradigms were modified by additional tissue-specific or expression biomarkers, and some frequently mutated genes were associated with sensitivity to a broad range of therapeutic agents. Unexpected relationships were revealed, including the marked sensitivity of Ewing’s sarcoma cells harboring the EWS-FLI1 gene translocation to PARP inhibitors. By linking drug activity to the functional complexity of cancer genomes, systematic pharmacogenomic profiling in cancer cell lines provides a powerful biomarker discovery platform to guide rational cancer therapeutic strategies. PMID:22460902

  7. Systematic identification of genomic markers of drug sensitivity in cancer cells.

    PubMed

    Garnett, Mathew J; Edelman, Elena J; Heidorn, Sonja J; Greenman, Chris D; Dastur, Anahita; Lau, King Wai; Greninger, Patricia; Thompson, I Richard; Luo, Xi; Soares, Jorge; Liu, Qingsong; Iorio, Francesco; Surdez, Didier; Chen, Li; Milano, Randy J; Bignell, Graham R; Tam, Ah T; Davies, Helen; Stevenson, Jesse A; Barthorpe, Syd; Lutz, Stephen R; Kogera, Fiona; Lawrence, Karl; McLaren-Douglas, Anne; Mitropoulos, Xeni; Mironenko, Tatiana; Thi, Helen; Richardson, Laura; Zhou, Wenjun; Jewitt, Frances; Zhang, Tinghu; O'Brien, Patrick; Boisvert, Jessica L; Price, Stacey; Hur, Wooyoung; Yang, Wanjuan; Deng, Xianming; Butler, Adam; Choi, Hwan Geun; Chang, Jae Won; Baselga, Jose; Stamenkovic, Ivan; Engelman, Jeffrey A; Sharma, Sreenath V; Delattre, Olivier; Saez-Rodriguez, Julio; Gray, Nathanael S; Settleman, Jeffrey; Futreal, P Andrew; Haber, Daniel A; Stratton, Michael R; Ramaswamy, Sridhar; McDermott, Ultan; Benes, Cyril H

    2012-03-28

    Clinical responses to anticancer therapies are often restricted to a subset of patients. In some cases, mutated cancer genes are potent biomarkers for responses to targeted agents. Here, to uncover new biomarkers of sensitivity and resistance to cancer therapeutics, we screened a panel of several hundred cancer cell lines--which represent much of the tissue-type and genetic diversity of human cancers--with 130 drugs under clinical and preclinical investigation. In aggregate, we found that mutated cancer genes were associated with cellular response to most currently available cancer drugs. Classic oncogene addiction paradigms were modified by additional tissue-specific or expression biomarkers, and some frequently mutated genes were associated with sensitivity to a broad range of therapeutic agents. Unexpected relationships were revealed, including the marked sensitivity of Ewing's sarcoma cells harbouring the EWS (also known as EWSR1)-FLI1 gene translocation to poly(ADP-ribose) polymerase (PARP) inhibitors. By linking drug activity to the functional complexity of cancer genomes, systematic pharmacogenomic profiling in cancer cell lines provides a powerful biomarker discovery platform to guide rational cancer therapeutic strategies.

  8. Nonsteroidal anti-inflammatory drug sensitizes Mycobacterium tuberculosis to endogenous and exogenous antimicrobials

    PubMed Central

    Gold, Ben; Pingle, Maneesh; Brickner, Steven J.; Shah, Nilesh; Roberts, Julia; Rundell, Mark; Bracken, W. Clay; Warrier, Thulasi; Somersan, Selin; Venugopal, Aditya; Darby, Crystal; Jiang, Xiuju; Warren, J. David; Fernandez, Joseph; Ouerfelli, Ouathek; Nuermberger, Eric L.; Cunningham-Bussel, Amy; Rath, Poonam; Chidawanyika, Tamutenda; Deng, Haiteng; Realubit, Ronald; Glickman, J. Fraser; Nathan, Carl F.

    2012-01-01

    Existing drugs are slow to eradicate Mycobacterium tuberculosis (Mtb) in patients and have failed to control tuberculosis globally. One reason may be that host conditions impair Mtb’s replication, reducing its sensitivity to most antiinfectives. We devised a high-throughput screen for compounds that kill Mtb when its replication has been halted by reactive nitrogen intermediates (RNIs), acid, hypoxia, and a fatty acid carbon source. At concentrations routinely achieved in human blood, oxyphenbutazone (OPB), an inexpensive anti-inflammatory drug, was selectively mycobactericidal to nonreplicating (NR) Mtb. Its cidal activity depended on mild acid and was augmented by RNIs and fatty acid. Acid and RNIs fostered OPB’s 4-hydroxylation. The resultant 4-butyl-4-hydroxy-1-(4-hydroxyphenyl)-2-phenylpyrazolidine-3,5-dione (4-OH-OPB) killed both replicating and NR Mtb, including Mtb resistant to standard drugs. 4-OH-OPB depleted flavins and formed covalent adducts with N-acetyl-cysteine and mycothiol. 4-OH-OPB killed Mtb synergistically with oxidants and several antituberculosis drugs. Thus, conditions that block Mtb’s replication modify OPB and enhance its cidal action. Modified OPB kills both replicating and NR Mtb and sensitizes both to host-derived and medicinal antimycobacterial agents. PMID:23012453

  9. Monitoring temperature-sensitive vaccines and immunologic drugs, including anthrax vaccine.

    PubMed

    Frank, K J

    1999-10-15

    The experience of the U.S. Army Medical Materiel Center, Europe (USAMMCE), in monitoring temperature-sensitive vaccines and immunologic drugs, including anthrax vaccine, during storage and shipment is discussed. USAMMCE uses an electronic monitoring device to monitor and archive the time-temperature history of shipments of various vaccines, immunoglobulins, and other drugs requiring refrigeration. Using these monitors, USAMMCE can track its carriers' performance, reduce product loss, and validate quality. USAMMCE trains people to pack refrigerated items and to activate and place the monitoring device inside the packing container. Over 1200 temperature-monitor readings from 44 U.S. military logistical depots, hospitals, and clinics located outside the United States are evaluated annually by the USAMMCE pharmacist; each reading represents one shipment or packed box. When deactivated during unpacking, the device flashes green for a successful shipment (all temperature readings within the ideal range) or red for a potentially problematic shipment. From January through October 1998, the device was used in 750 temperature-sensitive shipments; 72% of the devices were returned to USAMMCE in green condition and the remainder in red. Of the red-flashing monitors, 15% were determined to signal that the drugs were received in unacceptable condition. USAMMCE successfully shipped more than 26,000 vials of anthrax vaccine from February through October 1998 within the manufacturer's guidelines for storage temperature. Temperature monitoring is essential for proper storage and transport of vaccines and immunologic drugs.

  10. Formulation and characterization of sustained release dosage form of moisture sensitive drug

    PubMed Central

    Patel, Priya; Dave, Abhishek; Vasava, Amit; Patel, Paresh

    2015-01-01

    Objective: The purpose of this study was to prepare sustained release tablet of moisture sensitive drug like Ranitidine Hydrochloride for treatment of gastroesophageal reflux disease along with the improvement of moisture stability to get better therapeutic efficacy. Materials and Methods: Pan coating technique was used for coating of the tablet. Film coating was done using Eudragit RLPO and Eugragit EPO as coating polymer. 32 full factorial design was applied for optimization purpose, and 9 runs were conducted. In that Eudragit RLPO and Eudragit EPO taken as an independent variables and moisture gain and Cummulative Drug Release (CDR) were taken as dependent variables. Drug and excipient compatibility was done using differential scanning calorimetry and Fourier transform infrared spectroscopy study. The tablet was evaluated for precompression parameter and all postcompression parameter. Stability study was carried out at room temperature (30°C ± 2°C/65% ± 5% relative humidity). Final formulation was compared with marketed formulation RANTEC 300. Result: Tablets were passing out all precompression parameter along with postcompression parameter. Stability study shows that the parameter such as hardness, friability, and dissolution are in the range. Hence, there is no significant change shown after stability study. Our final formulation was compared with marketed formulation RANTEC 300 and result demonstrates that our final formulation have less moisture gain and give release up to 12 h. Conclusion: The result of present study demonstrates that final formulation has less moisture gain and getting desired CDR for sustained release of drug. On the basis of all study, it was concluded that the tablet was coated by combination of Eudragit RLPO 10% and Eudragit EPO 10% give better result. This formation provided promising approach for the drug release up to 12 h for moisture sensitive drug like ranitidine hydrochloride. PMID:25838994

  11. Keto-Mycolic Acid-Dependent Pellicle Formation Confers Tolerance to Drug-Sensitive Mycobacterium tuberculosis

    PubMed Central

    Sambandan, Dhinakaran; Dao, Dee N.; Weinrick, Brian C.; Vilchèze, Catherine; Gurcha, Sudagar S.; Ojha, Anil; Kremer, Laurent; Besra, Gurdyal S.; Hatfull, Graham F.; Jacobs, William R.

    2013-01-01

    ABSTRACT The chronic nature of tuberculosis (TB), its requirement of long duration of treatment, its ability to evade immune intervention, and its propensity to relapse after drug treatment is discontinued are reminiscent of other chronic, biofilm-associated bacterial diseases. Historically, Mycobacterium tuberculosis was grown as a pellicle, a biofilm-like structure, at the liquid-air interface in a variety of synthetic media. Notably, the most widely administered human vaccine, BCG, is grown as a pellicle for vaccine production. However, the molecular requirements for this growth remain ill defined. Here, we demonstrate that keto-mycolic acids (keto-MA) are essential for pellicle growth, and mutants lacking in or depleted of this MA species are unable to form a pellicle. We investigated the role of the pellicle biofilm in the reduction of antibiotic sensitivity known as drug tolerance using the pellicle-defective ΔmmaA4 mutant strain. We discovered that the ΔmmaA4 mutant, which is both pellicle defective and highly sensitive to rifampicin (RIF) under planktonic growth, when incorporated within the wild-type pellicle biofilm, was protected from the bactericidal activity of RIF. The observation that growth within the M. tuberculosis pellicle biofilm can confer drug tolerance to a drug-hypersensitive strain suggests that identifying molecular requirements for pellicle growth could lead to development of novel interventions against mycobacterial infections. Our findings also suggest that a class of drugs that can disrupt M. tuberculosis biofilm formation, when used in conjunction with conventional antibiotics, has the potential to overcome drug tolerance. PMID:23653446

  12. [Screening the Drug Sensitivity Genes Related to GEM and CDDP in the Lung Cancer Cell-lines.].

    PubMed

    Yang, Chunyu; Tian, Zhennan; Liu, Wei; Cai, Li

    2009-10-20

    Background and objective Screening of small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) cell lines with gemcitabine hydrochloride (GEM) and cisplatin (CDDP) related to drug sensitivity gene might clarify the action mechanism of anti-cancer drugs and provide a new clue for overcoming drug resistance and the development of new anti-cancer drugs, and also provide theoretical basis for the clinical treatment of individual. The drug sensitivity of CDDP and GEM in 4 SCLC cell lines and 6 NSCLC cell lines was determined using MTT colorimetric assay, while the cDNA macroarray was applied to detect the gene expression state related to drug sensitivity of 10 lung cancer cell line in 1 291, and the correlation between the two was analysized. There were 6 genes showing significant positive correlation (r>=0.632, P<0.05) with GEM sensitivity; 45 genes positively related to CDDP; another 41 genes related to both GEM and CDDP (r>=+/- 0.4). Lung cancer with GEM and CDDP sensitivity of two types of drugs significantly related genes were Metallothinein (Signal transduction molecules), Cathepsin B (Organization protease B) and TIMP1 (Growth factor); the GEM, CDDP sensitivity associated genes of lung cancer cell lines mainly distributed in Metallothinein, Cathepsin B, growth factor TIMP1 categories. There existed drug-related sensitive genes of GEM, CDDP in SCLC and NSCLC cell lines; of these genes, Metallothinein, Cathepsin B and TIMP1 genes presented a significant positive correlation with GEM drug sensitivity, a significant negative correlation with CDDP drug sensitivity.

  13. [Sensitivity and specificity of nested PCR pyrosequencing in hepatitis B virus drug resistance gene testing].

    PubMed

    Sun, Shumei; Zhou, Hao; Zhou, Bin; Hu, Ziyou; Hou, Jinlin; Sun, Jian

    2012-05-01

    To evaluate the sensitivity and specificity of nested PCR combined with pyrosequencing in the detection of HBV drug-resistance gene. RtM204I (ATT) mutant and rtM204 (ATG) nonmutant plasmids mixed at different ratios were detected for mutations using nested-PCR combined with pyrosequencing, and the results were compared with those by conventional PCR pyrosequencing to analyze the linearity and consistency of the two methods. Clinical specimens with different viral loads were examined for drug-resistant mutations using nested PCR pyrosequencing and nested PCR combined with dideoxy sequencing (Sanger) for comparison of the detection sensitivity and specificity. The fitting curves demonstrated good linearity of both conventional PCR pyrosequencing and nested PCR pyrosequencing (R(2)>0.99, P<0.05). Nested PCR showed a better consistency with the predicted value than conventional PCR, and was superior to conventional PCR for detection of samples containing 90% mutant plasmid. In the detection of clinical specimens, Sanger sequencing had a significantly lower sensitivity than nested PCR pyrosequencing (92% vs 100%, P<0.01). The detection sensitivity of Sanger sequencing varied with the viral loads, especially in samples with low viral copies (HBV DNA ≤3log10 copies/ml), where the sensitivity was 78%, significantly lower than that of pyrosequencing (100%, P<0.01). Neither of the two methods yielded positive results for the negative control samples, suggesting their good specificity. Compared with nested PCR and Sanger sequencing method, nested PCR pyrosequencing has a higher sensitivity especially in clinical specimens with low viral copies, which can be important for early detection of HBV mutant strains and hence more effective clinical management.

  14. Rad51 and BRCA2--New molecular targets for sensitizing glioma cells to alkylating anticancer drugs.

    PubMed

    Quiros, Steve; Roos, Wynand Paul; Kaina, Bernd

    2011-01-01

    First line chemotherapeutics for brain tumors (malignant gliomas) are alkylating agents such as temozolomide and nimustine. Despite growing knowledge of how these agents work, patients suffering from this malignancy still face a dismal prognosis. Alkylating agents target DNA, forming the killing lesion O(6)-alkylguanine, which is converted into DNA double-strand breaks (DSBs) that trigger apoptosis. Here we assessed whether inhibiting repair of DSBs by homologous recombination (HR) or non-homologous end joining (NHEJ) is a reasonable strategy for sensitizing glioma cells to alkylating agents. For down-regulation of HR in glioma cells, we used an interference RNA (iRNA) approach targeting Rad51 and BRCA2, and for NHEJ we employed the DNA-PK inhibitor NU7026. We also assessed whether inhibition of poly(ADP)ribosyltransferase (PARP) by olaparib would enhance the killing effect. The data show that knockdown of Rad51 or BRCA2 greatly sensitizes cells to DSBs and the induction of cell death following temozolomide and nimustine (ACNU). It did not sensitize to ionizing radiation (IR). The expression of O(6)-methylguanine-DNA methyltransferase (MGMT) abolished all these effects, indicating that O(6)-alkylguanine induced by these drugs is the primary lesion responsible for the formation of DSBs and increased sensitivity of glioma cells following knockdown of Rad51 and BRCA2. Inhibition of DNA-PK only slightly sensitized to temozolomide whereas a significant effect was observed with IR. A triple strategy including siRNA and the PARP inhibitor olaparib further improved the killing effect of temozolomide. The data provides evidence that down-regulation of Rad51 or BRCA2 is a reasonable strategy for sensitizing glioma cells to killing by O(6)-alkylating anti-cancer drugs. The data also provide proof of principle that a triple strategy involving down-regulation of HR, PARP inhibition and MGMT depletion may greatly enhance the therapeutic effect of temozolomide.

  15. Carboxymethyl cellulose modified graphene oxide as pH-sensitive drug delivery system.

    PubMed

    Rao, Ziqie; Ge, Hongyu; Liu, Liangling; Zhu, Chen; Min, Lian; Liu, Meng; Fan, Lihong; Li, Dan

    2017-09-23

    Nanotechnology has been studied to improve drug delivery and cancer treatment. The aim of this study is to introduce amino groups into graphene oxide (GO) to form aminated fumed graphene (GO-ADH) and combine GO-ADH with carboxymethyl cellulose (CMC) to produce GO-CMC complex as a drug carrier matrix. The anti-cancer drug small molecule doxorubicin hydrochloride (DOX) was bond to GO-CMC by π-π bond interaction and hydrogen bonding to form GO-CMC/DOX drug loading system. Via the FT-IR, transmission electron microscopy (TEM) and Zeta potential analyzer analysis showed that GO-CMC complex was successfully synthesized. Studies have shown that when pH=5.0, the cumulative release rate of drugs can reach 65.2%, which means it has pH-sensitive ability. The cells were treated with MTT method and human cervical cancer cells (Hela cells) and mouse fibroblasts (NIH-3T3 cells). The results showed that GO-CMC had no obvious cytotoxicity and good biocompatibility. Copyright © 2017. Published by Elsevier B.V.

  16. Sonochemically synthesized biocompatible zirconium phosphate nanoparticles for pH sensitive drug delivery application.

    PubMed

    Kalita, Himani; Prashanth Kumar, B N; Konar, Suraj; Tantubay, Sangeeta; Kr Mahto, Madhusudan; Mandal, Mahitosh; Pathak, Amita

    2016-03-01

    The present work reports the synthesis of biocompatible zirconium phosphate (ZP) nanoparticles as nanocarrier for drug delivery application. The ZP nanoparticles were synthesized via a simple sonochemical method in the presence of cetyltrimethylammonium bromide and their efficacy for the delivery of drugs has been tested through various in-vitro experiments. The particle size and BET surface area of the nanoparticles were found to be ~48 nm and 206.51 m(2)/g respectively. The conventional MTT assay and cellular localization studies of the particles, performed on MDA-MB-231 cell lines, demonstrate their excellent biocompatibility and cellular internalization behavior. The loading of curcumin, an antitumor drug, onto the ZP nanoparticles shows the rapid drug uptake ability of the particles, while the drug release study, performed at two different pH values (at 7.4 and 5) depicts pH sensitive release-profile. The MTT assay and cellular localization studies revealed higher cellular inhibition and better bioavailability of the nanoformulated curcumin compared to free curcumin.

  17. Design of an Inflammation-Sensitive Polyelectrolyte-Based Topical Drug Delivery System for Arthritis.

    PubMed

    Bijukumar, Divya; Choonara, Yahya E; Murugan, Karmani; Choonara, Bibi Fatima; Kumar, Pradeep; du Toit, Lisa C; Pillay, Viness

    2016-10-01

    The most successful treatment strategy for arthritis is intra-articular injections that are costly and have reduced patient compliance. The purpose of the current study was to develop an inflammation-sensitive system for topical drug administration. Multi-macromolecular alginate-hyaluronic acid-chitosan (A-H-C) polyelectrolyte complex nanoparticles, loaded with indomethacin were developed employing pre-gel and post-gel techniques in the presence of dodecyl-L-pyroglutamate (DLP). In addition to in vitro studies, in silico simulations were performed to affirm and associate the molecular interactions inherent to the formulation of core all-natural multi-component biopolymeric architectures composed of an anionic (alginate), a cationic (chitosan), and an amphi-ionic polyelectrolytic (hyaluronic acid) macromolecule. The results demonstrated that DLP significantly influenced the size of the synthesized nanoparticles. Drug-content analysis revealed higher encapsulation efficiency (77.3%) in the presence of DLP, irrespective of the techniques used. Moreover, in vitro drug release studies showed that indomethacin release from the nanosystem was significantly improved (98%) in Fenton's reagent. Drug permeation across a cellulose membrane using a Franz diffusion cell system showed an initial surge flux (0.125 mg/cm(-2)/h), followed by sustained release of indomethacin for the post-gel nanoparticles revealing its effective skin permeation efficiency. In conclusion, the study presents novel nanoparticles which could effectively encapsulate and deliver hydrophobic drugs to the target site, particularly for arthritis.

  18. Quantitative study of the drug efflux kinetics from sensitive and MDR human breast cancer cells.

    PubMed

    Zhou, Chenguang; Shen, Peng; Cheng, Yiyu

    2007-07-01

    Cancer multidrug resistance (MDR) is a major impediment to effective chemotherapy in human cancer, in which P-glycoprotein and Multidrug Resistance-Associated protein figure prominently. Design and exploitation of novel clinical MDR inhibitors is greatly hindered by a lack of understanding of drug efflux dynamics in drug-sensitive and resistant cells. The aim of our study was to provide a microelectrode method for measuring the multidrug transporter mediated efflux of doxorubicin as well as a corresponding data analysis method for quantifying the efflux kinetic parameters. We performed experiments using carbon fiber microelectrode to detect doxorubicin efflux from a monolayer of human breast cancer MCF-7 cells and derived MDR cells (MCF-7/ADR), established a material transport model and proposed a novel inverse method to quantitatively characterize the diffusion dynamics. The kinetic parameters of doxorubicin efflux from MCF-7 and MCF-7/ADR cells in the presence or absence of MDR inhibitors were estimated. Our investigations showed the average initial doxorubicin efflux rate of MCF-7/ADR that was 5.2 times faster than of MCF-7. After treatment by tetramethylpyrazine or verapamil, the drug efflux rate of the MCF-7/ADR cells was reduced by about half that of those without inhibitors. The novel methodology presented suggests new and expanded applications for computer-aided reconstruction of the drug efflux process, microelectrode design, and high-throughput drug screening.

  19. Prevalence of sensitivity to food and drug additives in patients with chronic idiopathic urticaria.

    PubMed

    Rajan, Jessica P; Simon, Ronald A; Bosso, John V

    2014-01-01

    Chronic idiopathic urticaria (CIU) is defined as the presence of urticaria most days of the week for a period of 6 weeks or longer. There have been reports of food additive sensitivity in CIU previously, but the prevalence has not been precisely determined. To determine the prevalence of reactions to food and drug additives in patients with CIU. We challenged 100 patients in our allergy/immunology division with CIU to the 11 additives most commonly associated with reactions: tartrazine (FD&C Yellow 5), potassium metabisulfite, monosodium glutamate, aspartame, sodium benzoate, methyl paraben, butylated hydroxy anisole, butylated hydroxy toluene, FD&C Yellow 6, sodium nitrate, sodium nitrite. All of the patients had a history of CIU for longer than 6 weeks, and 43 reported possible history of food or drug additive sensitivity. Single-blind challenges to all of the additives were performed in the clinic and skin scores were recorded. Subjects with positive challenge tests underwent double-blind placebo controlled challenges. Of 100 subjects, only 2 had a positive urticarial response on single-blind challenge. Neither of these patients had a positive urticarial response on double-blind placebo-controlled challenge. There were no gastrointestinal, respiratory, or other symptom, and no patients reported late reactions. We were able to conclude, with 95% confidence intervals that sensitivity to any of the 11 food and drug additives occurs in fewer than 1% of patients with CIU. Food and drug additives appear to be a rare cause of CIU, and avoidance is not recommended. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  20. RNA-seq reveals determinants of sensitivity to chemotherapy drugs in esophageal carcinoma cells.

    PubMed

    Yang, Li-Xin; Li, Bai-Ling; Liu, Xiao-Hong; Yuan, Yang; Lu, Chao-Jing; Chen, Rui; Zhao, Jian

    2014-01-01

    Chemotherapy remains the mainstay of treatment for patients with incurable disease of esophageal carcinoma. Most patients respond poorly to chemotherapy, it is necessary to figure out biomarkers for chemotherapy sensitivity or resistance to perform the individualized therapy. In present work, the sensitivities of two ESCC cell lines to 9 chemotherapy drugs were identified and the transcriptome of these two cell lines were investigated by RNA-seq, the correlation between the sensitivity to drugs and expression of some genes was attempted to construct. Eca-1 was more resistant to most of the chemotherapy drugs than Eca-109 cell line. RNA-seq results showed that there is dramatic difference in the basal expression between these two ESCC cell lines. Pathway analysis demonstrated that these differentially expressed genes were mainly enriched in Gαi signaling, calcium signaling, cAMP-mediated signaling, G-protein coupled receptor signaling and actin cytoskeleton signaling pathways. The molecules in Gαi signaling (ADCY1 and SSTR3) and actin cytoskeleton signaling (MYH6 and MYH7) were highly expressed in multidrug-resistant Eca-1 cells, which were validated by quantitative PCR. Activation of these two pathways results in the upregulation of downstream signaling, PKA signaling and Src-STAT3, and downregulation of RAF-ERK signaling, which was validated by immunoblotting experiments. Our work proposed that activation of Gαi signaling or actin cytoskeleton signaling may confer ESCC cells resistance to most chemotherapy drugs. Our work might provide potential biomarkers and therapeutic targets for treatment of EC patients.

  1. RNA-seq reveals determinants of sensitivity to chemotherapy drugs in esophageal carcinoma cells

    PubMed Central

    Yang, Li-Xin; Li, Bai-Ling; Liu, Xiao-Hong; Yuan, Yang; Lu, Chao-Jing; Chen, Rui; Zhao, Jian

    2014-01-01

    Chemotherapy remains the mainstay of treatment for patients with incurable disease of esophageal carcinoma. Most patients respond poorly to chemotherapy, it is necessary to figure out biomarkers for chemotherapy sensitivity or resistance to perform the individualized therapy. In present work, the sensitivities of two ESCC cell lines to 9 chemotherapy drugs were identified and the transcriptome of these two cell lines were investigated by RNA-seq, the correlation between the sensitivity to drugs and expression of some genes was attempted to construct. Eca-1 was more resistant to most of the chemotherapy drugs than Eca-109 cell line. RNA-seq results showed that there is dramatic difference in the basal expression between these two ESCC cell lines. Pathway analysis demonstrated that these differentially expressed genes were mainly enriched in Gαi signaling, calcium signaling, cAMP-mediated signaling, G-protein coupled receptor signaling and actin cytoskeleton signaling pathways. The molecules in Gαi signaling (ADCY1 and SSTR3) and actin cytoskeleton signaling (MYH6 and MYH7) were highly expressed in multidrug-resistant Eca-1 cells, which were validated by quantitative PCR. Activation of these two pathways results in the upregulation of downstream signaling, PKA signaling and Src-STAT3, and downregulation of RAF-ERK signaling, which was validated by immunoblotting experiments. Our work proposed that activation of Gαi signaling or actin cytoskeleton signaling may confer ESCC cells resistance to most chemotherapy drugs. Our work might provide potential biomarkers and therapeutic targets for treatment of EC patients. PMID:24817948

  2. Hepatic drug metabolizing profile of Flinders Sensitive Line rat model of depression.

    PubMed

    Kotsovolou, Olga; Ingelman-Sundberg, Magnus; Lang, Matti A; Marselos, Marios; Overstreet, David H; Papadopoulou-Daifoti, Zoi; Johanson, Inger; Fotopoulos, Andrew; Konstandi, Maria

    2010-08-16

    The Flinders Sensitive Line (FSL) rat model of depression exhibits some behavioral, neurochemical, and pharmacological features that have been reported in depressed patients and has been very effective in screening antidepressants. Major factor that determines the effectiveness and toxicity of a drug is the drug metabolizing capacity of the liver. Therefore, in order to discriminate possible differentiation in the hepatic drug metabolism between FSL rats and Sprague-Dawley (SD) controls, their hepatic metabolic profile was investigated in this study. The data showed decreased glutathione (GSH) content and glutathione S-transferase (GST) activity and lower expression of certain major CYP enzymes, including the CYP2B1, CYP2C11 and CYP2D1 in FSL rats compared to SD controls. In contrast, p-nitrophenol hydroxylase (PNP), 7-ethoxyresorufin-O-dealkylase (EROD) and 16alpha-testosterone hydroxylase activities were higher in FSL rats. Interestingly, the wide spread environmental pollutant benzo(alpha)pyrene (B(alpha)P) induced CYP1A1, CYP1A2, CYP2B1/2 and ALDH3c at a lesser extend in FSL than in SD rats, whereas the antidepressant mirtazapine (MIRT) up-regulated CYP1A1/2, CYP2C11, CYP2D1, CYP2E1 and CYP3A1/2, mainly, in FSL rats. The drug also further increased ALDH3c whereas suppressed GSH content in B(alpha)P-exposed FSL rats. In conclusion, several key enzymes of the hepatic biotransformation machinery are differentially expressed in FSL than in SD rats, a condition that may influence the outcome of drug therapy. The MIRT-induced up-regulation of several drug-metabolizing enzymes indicates the critical role of antidepressant treatment that should be always taken into account in the designing of treatment and interpretation of insufficient pharmacotherapy or drug toxicity.

  3. Sensitive Determination of Sertraline in Commercial Drugs and Its Stability Check in Simulated Gastric Juice.

    PubMed

    Koçoğlu, Elif Seda; Bakırdere, Sezgin; Keyf, Seyfullah

    2016-11-01

    A sensitive analytical method was developed for the determination of sertraline in commercial drug samples by using GC-MS. The selected-ion monitoring mode was used at the most sensitive m/z 274 to obtain a lower detection limit. LOD/LOQ values were obtained as 1.6/5.4 ng/mL for sertraline under the optimum conditions. The calibration plot was linear between 5.0 and 2000 ng/mL with the correlation coefficient of 0.9999. The validated method was successfully applied to three different brands of drug samples for both qualitative and quantitative measurement of sertraline. In this experiment, four replicate extractions were performed for each brand, and the results were compared to the values written on the labels of the drug brands. Spiking experiments were also performed to check the effect of the matrixes on the determination, and it was observed that there was no shift in the retention time of the analyte. In addition, simulated gastric juice experiments were performed to check the stability of sertraline in the stomach for 240 min, and it was observed that there was no change in the structure of the analyte.

  4. Stimuli-sensitive hollow spheres from chitosan-graft-β-cyclodextrin for controlled drug release.

    PubMed

    Yu, Nana; Li, Guiying; Gao, Yurong; Liu, Xunyong; Ma, Songmei

    2016-12-01

    In this paper, sensitive polymeric hollow spheres self-assembled from chitosan-grafted-β-cyclodextrin (CS-g-CD) and sodium tripolyphosphate (TPP) were prepared for controlled release of doxorubicin (DOX). The assemblies were formed by electrostatic interactions between positively charged amino group in CS-g-CD and negatively charged phosphate in TPP. The hollow spheres with diameters about 100nm were confirmed by transmission electron microscopy (TEM) and laser particle analyzer. The microspheres with hollow cavity were beneficial to improve the drug loading capacity for DOX with entrapment efficiency above 60%. The cumulative release of DOX from CS-g-CD/TPP hollow microspheres increased with the decrease of pH and the increase of temperature or ionic strength. At 37 °C and pH 5.2, the maximum drug release was above 90% with a continuous release rate. In-vitro cytotoxicity tests indicate that drug loaded hollow spheres exhibited evidently inhibition against cancer cells. These sensitive polymeric hollow spheres are expected to be used in biomedical field as potential carrier. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Polydopamine-based surface modification of mesoporous silica nanoparticles as pH-sensitive drug delivery vehicles for cancer therapy.

    PubMed

    Chang, Danfeng; Gao, Yongfeng; Wang, Lijun; Liu, Gan; Chen, Yuhan; Wang, Teng; Tao, Wei; Mei, Lin; Huang, Laiqiang; Zeng, Xiaowei

    2016-02-01

    A novel pH-sensitive drug delivery system of mesoporous silica nanoparticles (MSNs) which were modified by polydopamine (PDA) for controlled release of cationic amphiphilic drug desipramine (DES) was prepared. MSNs-DES-PDA were characterized in terms of size, size distribution, surface morphology, BET surface area, mesoporous size and pore volume, drug loading content and in vitro drug release profile. MSNs-DES-PDA had high drug loading content and pH sensitivity. The DES release profiles of MSNs-DES and MSNs-DES-PDA were totally different, and the drug release of MSNs-DES-PDA accelerated with increasing acidity. MSNs-DES-PDA can be internalized into cells. In vitro experiments demonstrated that MSNs-DES-PDA had higher cytotoxicity and inhibitory effects on acid sphingomyelinase than those of free DES. This drug delivery system was beneficial for controlled release and cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Effects of hiking at altitude on body composition and insulin sensitivity in recovering drug addicts.

    PubMed

    Lee, Wen-Chih; Chen, Jin-Jong; Hunt, Desmond D; Hou, Chien-Wen; Lai, Yu-Chiang; Lin, Fang-Ching; Chen, Chung-Yu; Lin, Ching-Hung; Liao, Yi-Hung; Kuo, Chia-Hua

    2004-10-01

    In the current study individuals with a history of drug abuse (users of heroin, cocaine, or amphetamine) displayed a 13-100% increase in body weight (self-reported) and exhibited a trend toward insulin resistance. Therefore, we investigated the effects of long-term altitude hiking on insulin sensitivity in this special population. Nine males recovering from drug addiction (ex-addicts) (age 28.7 +/- 1.3 years) and 17 control subjects (age 29 +/- 1.1 years) voluntarily participated in a 25-day hiking activity (altitude 2200-3800 M). On the 25th day of hiking, oral glucose tolerance test (OGTT), insulin response, lean body mass, fat mass, and waist-to-hip ratio (WHR) were measured in all subjects. After the altitude expedition, insulin levels during the OGTT in ex-addicts were similar to controls, suggesting that insulin sensitivity in this special population was normalized by long-term altitude activity. Along with improvements in insulin sensitivity, a significant reduction in WHR, but small increase in lean body mass, was observed. Twenty-five days of altitude activity significantly reverses hyperinsulinemia in the ex-addicts and this improvement appears to be partially associated with the reduction in central fatness.

  7. Monitoring drug induced apoptosis and treatment sensitivity in non-small cell lung carcinoma using dielectrophoresis.

    PubMed

    Taruvai Kalyana Kumar, Rajeshwari; Liu, Shanshan; Minna, John D; Prasad, Shalini

    2016-09-01

    Non-invasive real time methods for characterizing biomolecular events that contribute towards apoptotic kinetics would be of significant importance in the field of cancer biology. Effective drug-induced apoptosis is an important factor for establishing the relationship between cancer genetics and treatment sensitivity. The objective of this study was to develop a non-invasive technique to characterize cancer cells that are undergoing drug-induced apoptosis. We used dielectrophoresis to determine apoptotic cells as early as 2h post drug treatment as compared to 24h with standard flow cytometry method using non-small cell lung cancer (NSCLC) adenocarcinoma cell line (HCC1833) as a study model. Our studies have shown significant differences in apoptotic cells by chromatin condensation, formation of apoptotic bodies and exposure of phosphatidylserine (PS) on the extracellular surface when the cells where treated with a potent Bcl-2 family inhibitor drug (ABT-263). Time lapse dielectrophoretic studies were performed over 24h period after exposure to ABT-263 at clinically relevant concentrations. The dielectrophoretic studies were compared to Annexin-V FITC flow assay for the detection of PS in mid-stage apoptosis using flow cytometry. As a result of physical and biochemical changes, inherent dielectric properties of cells undergoing varying stages of apoptosis showed amplified changes in their cytoplasmic and membrane capacitance. In addition, zeta potential of these fixed isolated cells was measured to obtain direct correlation to biomolecular events. Copyright © 2016. Published by Elsevier B.V.

  8. Light-sensitive intelligent drug delivery systems of coumarin-modified mesoporous bioactive glass.

    PubMed

    Lin, H-M; Wang, W-K; Hsiung, P-A; Shyu, S-G

    2010-08-01

    Functionalized mesoporous bioactive glasses (MBG) with photoactive coumarin demonstrates photo-responsive dimerization resulting in reversible gate operation. Coumarin-modified MBG was used as a drug delivery carrier to investigate drug storage/release characteristics using phenanthrene as a model drug. Irradiation with UV light (>310 nm) induced photo-dimerization of the coumarin-modified MBG, which led to the pores' closing with cyclobutane dimers and trapping of the guest phenanthrene in the mesopores. However, irradiating the dimerized-coumarin-modified MBG with shorter wavelength UV light (approximately 250 nm) regenerates the coumarin monomer derivative by the photo-cleavage of cyclobutane dimers, such that trapped guest molecules are released from the mesopores. The structural, morphological, textural and optical properties are well characterized by X-ray diffraction, transmission electron microscopy, N(2) adsorption/desorption, and UV-visible spectroscopy. The results reveal that the MBG exhibits the typical ordered characteristics of the hexagonal mesostructure. The system demonstrates great potential in light-sensitive intelligent drug delivery systems and disease therapy fields.

  9. Polydopamine-coated liposomes as pH-sensitive anticancer drug carriers.

    PubMed

    Zong, Wei; Hu, Ying; Su, Yingchun; Luo, Nan; Zhang, Xunan; Li, Qingchuan; Han, Xiaojun

    2016-05-01

    Stimuli-responsive drug carriers are considered to play important roles in chemotherapy. We fabricated pH-sensitive polydopamine-protected liposomes (liposome@PDA) drug delivery systems, which were characterised with microscope, scanning electron microscope (SEM), UV-vis spectrometer and Fourier transform infrared (FTIR) technieques. The typical chemotherapeutic agent, 5-fluorouracil (5-FU), was loaded into liposome@PDA capsules. The maximum release percentages of 5-FU are 3.2%, 29.5%, 52.7%, 76.7% in the solution with pH 7.42, 6.87, 4.11 and 3.16, respectively. The in vitro cell cytotoxity experiments were carried out using 5-FU-loaded capsules at pH 6.87 solution, which simulate the true pH around cancerous cells. At 1.5 μM concentration, the free 5-FU, 5-FU-loaded liposome capsules and 5-FU-loaded capsules showed the cell viability of 50.56%, 22.66% and 21.63%, respectively. It confirms that drug-loaded capsules performed better than free drug. The results demonstrate the great potential of liposome@PDA capsules as carriers in biomedical applications.

  10. Analysis of high-throughput RNAi screening data in identifying genes mediating sensitivity to chemotherapeutic drugs: statistical approaches and perspectives.

    PubMed

    Ye, Fei; Bauer, Joshua A; Pietenpol, Jennifer A; Shyr, Yu

    2012-01-01

    High-throughput RNA interference (RNAi) screens have been used to find genes that, when silenced, result in sensitivity to certain chemotherapy drugs. Researchers therefore can further identify drug-sensitive targets and novel drug combinations that sensitize cancer cells to chemotherapeutic drugs. Considerable uncertainty exists about the efficiency and accuracy of statistical approaches used for RNAi hit selection in drug sensitivity studies. Researchers require statistical methods suitable for analyzing high-throughput RNAi screening data that will reduce false-positive and false-negative rates. In this study, we carried out a simulation study to evaluate four types of statistical approaches (fold-change/ratio, parametric tests/statistics, sensitivity index, and linear models) with different scenarios of RNAi screenings for drug sensitivity studies. With the simulated datasets, the linear model resulted in significantly lower false-negative and false-positive rates. Based on the results of the simulation study, we then make recommendations of statistical analysis methods for high-throughput RNAi screening data in different scenarios. We assessed promising methods using real data from a loss-of-function RNAi screen to identify hits that modulate paclitaxel sensitivity in breast cancer cells. High-confidence hits with specific inhibitors were further analyzed for their ability to inhibit breast cancer cell growth. Our analysis identified a number of gene targets with inhibitors known to enhance paclitaxel sensitivity, suggesting other genes identified may merit further investigation. RNAi screening can identify druggable targets and novel drug combinations that can sensitize cancer cells to chemotherapeutic drugs. However, applying an inappropriate statistical method or model to the RNAi screening data will result in decreased power to detect the true hits and increase false positive and false negative rates, leading researchers to draw incorrect conclusions. In

  11. [Insulin sensitizer--anti-diabetic drugs, metformin and pioglitazone that can improve insulin resistance].

    PubMed

    Korenaga, Masaaki; Kawaguchi, Koutaro; Korenaga, Keiko; Uchida, Kouichi; Sakaida, Iso

    2006-06-01

    Nonalcoholic steatohepatitis (NASH), which is considered the hepatic manifestation of the metabolic syndrome is an increasingly cause of chronic liver disease in Japan. NASH is finally lead to liver cirrhosis and hepatocellular carcinoma as viral hepatitis, therefore, medical treatment should be considered, when NASH occurs. Treatment of patients with metabolic syndrome has been focused on the management of associated conditions such as obesity, hyperlipidemia, hypertension and hyperinsulinemia. Insulin resistance, that could accelerate liver inflammation and fibrosis by up-regulation of TNFa seems to be most important factor in many cases of NASH. The insulin-sensitizing drugs, which were biguanides (metformin) and thiazolidinediones (pioglitazone) have been shown to correct not only insulin resistance but also steatosis and inflammation in the liver. Metformin and pioglitazone might be useful drugs against NASH, however further investigations were needed.

  12. Temperature-sensitive hydrogels with SiO2-Au nanoshells for controlled drug delivery.

    PubMed

    Bikram, Malavosklish; Gobin, Andre M; Whitmire, Rachel E; West, Jennifer L

    2007-11-20

    Silica-gold (SiO(2)-Au) nanoshells are a new class of nanoparticles that consist of a silica dielectric core that is surrounded by a gold shell. These nanoshells are unique because their peak extinctions are very easily tunable over a wide range of wavelengths particularly in the near infrared (IR) region of the spectrum. Light in this region is transmitted through tissue with relatively little attenuation due to absorption. In addition, irradiation of SiO(2)-Au nanoshells at their peak extinction coefficient results in the conversion of light to heat energy that produces a local rise in temperature. Thus, to develop a photothermal modulated drug delivery system, we have fabricated nanoshell-composite hydrogels in which SiO(2)-Au nanoshells of varying concentrations have been embedded within temperature-sensitive hydrogels, for the purpose of initiating a temperature change with light. N-isopropylacrylamide-co-acrylamide (NIPAAm-co-AAm) hydrogels are temperature-sensitive hydrogels that were fabricated to exhibit a lower critical solution temperature (LCST) slightly above body temperature. The resulting composite hydrogels had the extinction spectrum of the SiO(2)-Au nanoshells in which the hydrogels collapsed reversibly in response to temperature (50 degrees C) and laser irradiation. The degree of collapse of the hydrogels was controlled by the laser fluence as well as the concentration of SiO(2)-Au nanoshells. Modulated drug delivery profiles for methylene blue, insulin, and lysozyme were achieved by irradiation of the drug-loaded nanoshell-composite hydrogels, which showed that drug release was dependent upon the molecular weight of the therapeutic molecule.

  13. Novel pH-sensitive hydrogels for colon-specific drug delivery.

    PubMed

    Mahkam, Mehrdad

    2010-04-01

    The purpose of this study is to develop novel intestinal specific drug delivery systems with pH-sensitive swelling and drug release properties. Acryloyl ester of 5-[4-(hydroxy phenyl) azo] salicylic acid (HPAS) as an azo derivative of 5-amino salicylic acid (5-ASA) was prepared under mild conditions. The HPAS was covalently linked with acryloyl chloride, abbreviated as APAS. Cubane-1,4-dicarboxylic acid (CDA), linked to two 2-hydroxyethyl methacrylate (HEMA) groups, was the cross-linking agent (CA). Methacrylic-type polymeric prodrugs were synthesized by free radical copolymerization of methacrylic acid, poly(ethyleneglycol monomethyl ether methacrylate), and APAS in the presence of cubane cross-linking agent. The effect of copolymer composition on the swelling behavior and hydrolytic degradation were studied in simulated gastric (SGF, pH 1) and intestinal fluids (SIF, pH 7.4). The composition of the cross-linked three-dimensional polymers was determined by FTIR spectroscopy. The hydrolysis of drug-polymer conjugates was carried out in cellophane membrane dialysis bags containing aqueous buffer solutions (pH 1 and pH 7.4) at 37 degrees C. Detection of the hydrolysis product by UV spectroscopy shows that the azo prodrug (HPAS) was released by hydrolysis of the ester bond located between the HPAS and the polymer chain. Drug release studies showed that the increasing content of MAA in the copolymer enhances hydrolysis in SIF. These results suggest that pH-sensitive systems could be useful for preparation of a muccoadhesive system and controlled release of HPAS as an azo derivative of 5-amino salicylic acid (5-ASA).

  14. MEK inhibitor enhances sensitivity to chemotherapeutic drugs in multidrug resistant hepatocellular carcinoma cells.

    PubMed

    Meng, Qingliang; He, Xiaoqi; Xie, Guangwei; Tian, Qingzhong; Shu, Xiaogang; Li, Jin; Xiao, Yong

    2017-09-01

    The aim of the present study was to investigate the association between the mitogen-activated protein kinase (MAPK) signal transduction pathway and multidrug resistance in hepatocellular carcinoma cells. A Cell Counting Kit-8 assay was used to determine the drug sensitivity of HepG2 and HepG2/ADM hepatocellular carcinoma cell lines in combination with the MAPK/extracellular-signal-regulated kinase kinase (MEK) inhibitor U0126. Flow cytometry was used to analyze the rate of apoptosis. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) mRNA expression following treatment with various concentrations of U0126. P-gp and MRP1 expression levels were measured using Western blot analysis. The half-maximal inhibitory concentration was markedly decreased in combination with U0126. RT-qPCR results demonstrated that the expression of multidrug resistance 1 (MDR1) and MRP1 in HepG2/ADM cells was increased 5.37- and 6-14-fold compared with that in HepG2 cells. Furthermore, the expression levels in HepG2/ADM cells were decreased following U0126 treatment in a dose-dependent manner. The expression of P-gp and MRP1 in HepG2/ADM cells was increased 2.68- and 2.76-fold compared with that in HepG2 cells. Furthermore, the expression levels in HepG/ADM cells were decreased following U0126 treatment in a dose-dependent manner. The results of the present study indicate that the MEK inhibitor U0126 enhances sensitivity to chemotherapeutic drugs by downregulating P-gp and MRP1 expression in resistant hepatocellular carcinoma cells. The combination of MEK inhibitor and conventional chemotherapeutic drugs may provide novel therapeutic prospects for the treatment of drug-resistant hepatocellular carcinoma.

  15. Active site similarity between human and Plasmodium falciparum phosphodiesterases: considerations for antimalarial drug design

    NASA Astrophysics Data System (ADS)

    Howard, Brittany L.; Thompson, Philip E.; Manallack, David T.

    2011-08-01

    The similarity between Plasmodium falciparum phosphodiesterase enzymes ( PfPDEs) and their human counterparts have been examined and human PDE9A was found to be a suitable template for the construction of homology models for each of the four PfPDE isoforms. In contrast, the architecture of the active sites of each model was most similar to human PDE1. Molecular docking was able to model cyclic guanosine monophosphate (cGMP) substrate binding in each case but a docking mode supporting cyclic adenosine monophosphate (cAMP) binding could not be found. Anticipating the potential of PfPDE inhibitors as anti-malarial drugs, a range of reported PDE inhibitors including zaprinast and sildenafil were docked into the model of PfPDEα. The results were consistent with their reported biological activities, and the potential of PDE1/9 inhibitor analogues was also supported by docking.

  16. The wisdom of crowds and the repurposing of artesunate as an anticancer drug

    PubMed Central

    Augustin, Yolanda; Krishna, Sanjeev; Kumar, Devinder; Pantziarka, Pan

    2015-01-01

    Artesunate, a semi-synthetic and water-soluble artemisinin-derivative used as an anti-malarial agent, has attracted the attention of cancer researchers due to a broad range of anti-cancer activity including anti-angiogenic, immunomodulatory and treatment-sensitisation effects. In addition to pre-clinical evidence in a range of cancers, a recently completed randomised blinded trial in colorectal cancer has provided a positive signal for further clinical investigation. Used perioperatively artesunate appears to reduce the rate of disease recurrence - and the Neo-Art trial, a larger Phase II RCT, is seeking to confirm this positive effect. However, artesunate is a generic medication, and as with other trials of repurposed drugs, the Neo-Art trial does not have commercial sponsorship. In an innovative move, the trial is seeking funds directly from members of the public via a crowd-funding strategy that may have resonance beyond this single trial. PMID:26557887

  17. Sensitivity of White and Opaque Candida albicans Cells to Antifungal Drugs.

    PubMed

    Craik, Veronica B; Johnson, Alexander D; Lohse, Matthew B

    2017-08-01

    White and opaque cells of Candida albicans have the same genome but differ in gene expression patterns, metabolic profiles, and host niche preferences. We tested whether these differences, which include the differential expression of drug transporters, resulted in different sensitivities to 27 antifungal agents. The analysis was performed in two different strain backgrounds; although there was strain-to-strain variation, only terbinafine hydrochloride and caspofungin showed consistent, 2-fold differences between white and opaque cells across both strains. Copyright © 2017 American Society for Microbiology.

  18. Hydroxychloroquine in polymorphic light eruption: a controlled trial with drug and visual sensitivity monitoring.

    PubMed

    Murphy, G M; Hawk, J L; Magnus, I A

    1987-03-01

    A double-blind controlled trial of oral hydroxychloroquine (HC) treatment in polymorphic light eruption (PLE) was completed in 13 patients on active treatment and 15 on placebo during June, July and August 1982. HC dose was 400 mg daily for the first month and 200 mg daily thereafter. Exposure to ambient solar ultraviolet radiation (UVR) was monitored throughout the trial by polysulphone film lapel badges. Patients scored their symptoms on a visual analogue scale. Drug concentration was monitored in plasma and hair, and oculotoxicity was assessed by visual contrast sensitivity. Moderate clinical improvement occurred, associated with a statistically significant improvement in skin rash (P less than 0.01).

  19. Sitamaquine Sensitivity in Leishmania Species Is Not Mediated by Drug Accumulation in Acidocalcisomes▿

    PubMed Central

    López-Martín, Carmen; Pérez-Victoria, José María; Carvalho, Luis; Castanys, Santiago; Gamarro, Francisco

    2008-01-01

    Sitamaquine (WR6026), an 8-aminoquinoline derivative, is a new antileishmanial oral drug. As a lipophilic weak base, it rapidly accumulates in acidic compartments, represented mainly by acidocalcisomes. In this work, we show that the antileishmanial action of sitamaquine is unrelated to its level of accumulation in these acidic vesicles. We have observed significant differences in sitamaquine sensitivity and accumulation between Leishmania species and strains, and interestingly, there is no correlation between them. However, there is a relationship between the levels of accumulation of sitamaquine and acidotropic probes, acidocalcisomes size, and polyphosphate levels. The Leishmania major AP3δ-null mutant line, in which acidocalcisomes are devoid of their usual polyphosphate and proton content, is unable to accumulate sitamaquine; however, both the parental strain and the AP3δ-null mutants showed similar sensitivities to sitamaquine. Our findings provide clear evidence that the antileishmanial action of sitamaquine is unrelated to its accumulation in acidocalcisomes. PMID:18794384

  20. [A Case of Drug-Induced Thrombocytopenia Resulting from Sensitivity to Oxaliplatin].

    PubMed

    Masuda, Taiki; Nagai, Kagami; Sanada, Katsuya

    2015-11-01

    A 67-year-old man was diagnosed with pulmonary metastasis from advanced transverse colon cancer. Thus, a local resection was performed. Adjuvant chemotherapy with mFOLFOX6 was started. Sixteen courses were carried out without problems. However, he complained of chills and chest discomfort 2 hours after beginning the 17th course of chemotherapy. Laboratory data showed remarkable thrombocytopenia, and platelet-associated IgG level was high. After administration of steroids and platelet transfusions, the platelet count improved. Therefore, we diagnosed drug-induced thrombocytopenia resulting from sensitivity to oxaliplatin (L-OHP). Since then, sLV5FU2 therapy was started, and the patient received the whole adjuvant chemotherapy without problems. Thrombocytopenia resulting from sensitivity to L-OHP is a relatively rare side effect. We herein report this case with a review of the relevant literature.

  1. Phase synchronization analysis of voltage-sensitive dye imaging during drug-induced epileptic seizures.

    NASA Astrophysics Data System (ADS)

    Takeshita, Daisuke; Tsytsarev, Vassiliy; Bahar, Sonya

    2008-03-01

    Epileptic seizures are generally held to result from excess and synchronized neural activity. However, recent studies have suggested that this is not necessarily the case. We investigate how the spatiotemporal pattern of synchronization changes during drug-induced in vivo neocortical seizures in rats. Epileptic seizures are caused by the potassium channel blocker 4-aminopyridine, which is often used in experiments to induce epileptic seizures. In our experiments, the neocortex is stained with the voltage-sensitive dye RH-1691. The intensity changes in dye fluorescence are measured by a CCD camera and are consistent with the signal from local field potential recording. We apply phase synchronization analysis to the voltage-sensitive dye signals from pairs of pixels in order to investigate the degree to which synchronization occurs, and how spatial patterns of synchrony may change, during the course of the seizure. Our preliminary results show that two distant pixels are well synchronized during a seizure event.

  2. Adenovirus replication as an in vitro probe for drug sensitivity in human tumors.

    PubMed

    Parsons, P G; Maynard, K R; Little, J H; McLeod, G R

    1986-04-01

    The feasibility of using adenovirus 5 as an in vitro probe for chemosensitivity in short-term cultures of human tumors was evaluated using human melanoma cell lines and primary cultures of melanoma biopsies. A convenient immunoperoxidase method was developed for quantitating viral replication 2 days after infection. Two different approaches were explored: the host cell reactivation assay (HCR) using drug-treated virus; and the viral capacity assay using drug-treated cells. The HCR assay detected sensitivity to 5-(3-methyl-1-triazeno)imidazole-4-carboxamide (MTIC) in Mer- (methyl excision repair deficient) cell lines as decreased ability of the cells to replicate MTIC-treated virus. This test should be applicable to DNA-damaging agents and repair-deficient tumors. Adenovirus replicated readily in nonproliferating primary cultures of melanoma biopsies; application of the HCR assays to this material identified one Mer- sample of 11 tested. Herpes viruses were not suitable for use in HCR because herpes simplex virus type 1 failed to distinguish Mer- from Mer+ melanoma cells; and nonproductive infection of MTIC-sensitive lymphoid cells with Epstein-Barr virus yielded an MTIC-resistant cell line. The second assay (viral capacity) involved determination of the inhibition of replication of untreated virus in treated cells. This approach correctly predicted sensitivity to hydroxyurea and deoxyadenosine in melanoma cell lines when compared with clonogenic survival assay. Viral capacity was also inhibited by cytosine arabinoside, fluorouracil, vincristine, adriamycin, 6-mercaptopurine and ionising radiation, and may therefore be useful for detecting sensitivity to a wide range of antitumor agents.

  3. Registered report: Systematic identification of genomic markers of drug sensitivity in cancer cells

    PubMed Central

    Vanden Heuvel, John P; Bullenkamp, Jessica

    2016-01-01

    The Reproducibility Project: Cancer Biology seeks to address growing concerns about the reproducibility in scientific research by conducting replications of selected experiments from a number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altmetric scores (Errington et al., 2014). This Registered Report describes the proposed replication plan of key experiments from “Systematic identification of genomic markers of drug sensitivity in cancer cells” by Garnett and colleagues, published in Nature in 2012 (Garnett et al., 2012). The experiments to be replicated are those reported in Figures 4C, 4E, 4F, and Supplemental Figures 16 and 20. Garnett and colleagues performed a high throughput screen assessing the effect of 130 drugs on 639 cancer-derived cell lines in order to identify novel interactions for possible therapeutic approaches. They then tested this approach by exploring in more detail a novel interaction they identified in which Ewing’s sarcoma cell lines showed an increased sensitivity to PARP inhibitors (Figure 4C). Mesenchymal progenitor cells (MPCs) transformed with the signature EWS-FLI1 translocation, the hallmark of Ewing’s sarcoma family tumors, exhibited increased sensitivity to the PARP inhibitor olaparib as compared to MPCs transformed with a different translocation (Figure 4E). Knockdown mediated by siRNA of EWS-FLI1 abrogated this sensitivity to olaparib (Figure 4F). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange, and the results of the replications will be published by eLife. DOI: http://dx.doi.org/10.7554/eLife.13620.001 PMID:27336789

  4. Codelivery of antitumor drug and gene by a pH-sensitive charge-conversion system.

    PubMed

    Guan, Xiuwen; Li, Yanhui; Jiao, Zixue; Lin, Lin; Chen, Jie; Guo, Zhaopei; Tian, Huayu; Chen, Xuesi

    2015-02-11

    In the present study, a gene and drug codelivery system was developed by electrostatic binding of polyethylenimine-poly(l-lysine)-poly(l-glutamic acid) (PELG), polyethylenimine (PEI), cis-aconityl-doxorubicin (CAD), and DNA. Zeta potential and drug release analysis confirmed the pH-responsive charge conversion and acid-sensitive drug release functional properties of the PELG/PEI/(DNA+CAD) system. Gel retardation assay and transfection experiment showed the codelivery system had effective DNA binding ability and good transfection efficiency on HepG2 cells. The therapeutic gene p53 was further employed to study its combinational effects with CAD. Cytotoxicity assay showed the half inhibitory concentration (IC50) of the PELG/PEI/(p53+CAD) codelivery system was lower than that of the gene or the drug delivery system. Confocal laser scanning microscopy (CLSM) showed that the drug and gene could be delivered into the cells simultaneously. A significant increase of p53 gene expression was achieved after HepG2 cells treated by PELG/PEI/(p53+CAD) codelivery system. The apoptosis experiment indicated clearly that the codelivery system could lead an effective apoptosis on tumor cells, which was beneficial for the treatment of cancer. The biodistribution and tumor accumulation of the codelivery system was explored via in vivo imaging in subcutaneous xenograft and in situ tumor models. The tumor and some major organs were excised and imaged, and the results showed that the codelivery system can accumulate efficiently in tumor for both tumor models. It can be suggested from the above results that the PELG/PEI/(DNA+CAD) codelivery system will have great potential applications in cancer therapy.

  5. Sensitive derivatization methods for the determination of genotoxic impurities in drug substances using hyphenated techniques.

    PubMed

    Raman, Nanduri V V S S; Prasad, Adapa V S S; Reddy, Kura Ratnakar

    2014-02-01

    Six sensitive derivatization methods for the determination of genotoxic impurities in selected drug substances were developed using hyphenated techniques. Some of the raw materials, reagents and reaction intermediates of the selected drug substances were identified as genotoxic impurities through DEREK software for windows. The genotoxic impurities which are amenable for derivatization were selected as substrates. Derivatizing agents were selected based on the functional groups of the genotoxic impurities. The chemistry involved in the derivatization was explained with suitable mechanisms. An appropriate hyphenated technique viz. LC-MS and GC-MS was opted based on the sensitivity and aromaticity of the derivatized genotoxic impurities. All the methods were validated as per International Conference on Harmonization guidelines. Correlation coefficient values were found about 0.99. The obtained % R.S.D values from replicate injections in the range of 2.3-4.8 and % recoveries of the added impurities in the range of 83.7-101.7 ensured the precision and accuracy, respectively.

  6. Magnetic and pH-sensitive nanoparticles for antitumor drug delivery.

    PubMed

    Yu, Shufang; Wu, Guolin; Gu, Xin; Wang, Jingjing; Wang, Yinong; Gao, Hui; Ma, Jianbiao

    2013-03-01

    A dually responsive nanocarrier with multilayer core-shell architecture was prepared based on Fe(3)O(4)@SiO(2) nanoparticles coated with mPEG-poly(l-Asparagine). Imidazole groups (pK(a)∼6.0) were tethered to the side chains of poly(l-Asparagine) segments by aminolysis. These nanoparticles were expected to be sensitive to both magnetic field and pH environment. The obtained materials were characterized with FTIR, dynamic light scattering, ζ-potential, TEM, TGA and hysteresis loop analysis. It was found that this Fe(3)O(4)@SiO(2)-polymer complex can form nano-scale core-shell-corona trilayer particles (∼250 nm) in aqueous solution. The Fe(3)O(4)@SiO(2), poly(L-Asparagine) and mPEG segments serve as a super-paramagnetic core, a pH-sensitive shell, and a hydrophilic corona, respectively. An antitumor agent, doxorubicin (DOX), was successfully loaded into the nanocarrier via combined actions of hydrophobic interaction and hydrogen bonding. The drug release profiles displayed a pH-dependent behavior. DOX release rate increased significantly as the ambient pH dropped from the physiological pH (7.4) to acidic (5.5). This is most likely due to protonation and a change in hydrophilicity of the imidazole groups in the poly(l-Asparagine) segments. This new approach may serve as a promising platform to formulate magnetic targeted drug delivery systems.

  7. The pH-sensitive polyampholyte nanogels: inclusion of carbon nanotubes for improved drug loading.

    PubMed

    Sankar, Rajavelu Murali; Seeni Meera, Kamal Mohamed; Samanta, Debasis; Jithendra, Panneerselvam; Mandal, Asit Baran; Jaisankar, Sellamuthu N

    2013-12-01

    We report a simple and facile method to prepare a novel pH sensitive polyampholyte nanogel by copolymerizing vinylimidazole (VIM) with acrylic acid (AA) using functionalized single-walled carbon nanotubes (f-SWCNTs) (as reinforcing material) and cyanuric chloride via an intermolecular quaternization reaction. The polyampholyte nanogels have been characterized by various microscopic and spectroscopic methods. These studies reveal that incorporation of nanotubes in cross-linked copolymer of poly(vinylimidazole-co-acrylic acid) (PVI-co-AA) form polyampholyte nanogel with enhanced physical properties. The thermal experiments show that the introduction of f-SWCNTs into PVI-co-AA has significant impact on the thermal stability of nanogels. The rheological study showed that the nanogel is more viscoelastic than native gel. MTT assay indicates that the prepared polyampholyte gels possess biocompatibility and cell viability. The nanogel is also useful material to load water-soluble drug such as promethazine hydrochloride. The releasing profile of the drug from the nanogel clearly shows the pH-sensitive property of the material.

  8. Investigations on the viscoelastic performance of pressure sensitive adhesives in drug-in-adhesive type transdermal films.

    PubMed

    Wolff, Hans-Michael; Irsan; Dodou, Kalliopi

    2014-08-01

    We aimed to investigate the effect of solubility parameter and drug concentration on the rheological behaviour of drug-in-adhesive films intended for transdermal application. Films were prepared over a range of drug concentrations (5%, 10% and 20% w/w) using ibuprofen, benzoic acid, nicotinic acid and lidocaine as model drugs in acrylic (Duro-Tak 87-4287 and Duro-Tak 87900A) or silicone (Bio-PSA 7-4301 and Bio-PSA 7-4302) pressure sensitive adhesives (PSAs). Saturation status of films was determined using light microscopy. Viscoelastic parameters were measured in rheology tests at 32°C. Subsaturated films had lower viscoelastic moduli whereas saturated films had higher moduli than the placebo films and/or a concentration-dependent increase in their modulus. Saturation concentration of each drug in the films was reflected by decreasing/increasing viscoelastic patterns. The viscoelastic windows (VWs) of the adhesive and drug-in-adhesive films clearly depicted the effect of solubility parameter differences, molar concentration of drug in the adhesive film and differences in PSA chemistry. Drug solubility parameters and molar drug concentrations have an impact on rheological patterns and thus on the adhesive performance of tested pressure sensitive adhesives intended for use in transdermal drug delivery systems. Use of the Flory equation in its limiting form was appropriate to predict drug solubility in the tested formulations.

  9. 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

  10. Sensitivity of a Ribavirin Resistant Mutant of Hepatitis C Virus to Other Antiviral Drugs

    PubMed Central

    Mihalik, Kathleen B.; Feigelstock, Dino A.

    2013-01-01

    Background While ribavirin mono-therapy regimens have minimal effect on patients with chronic hepatitis C virus (HCV) infections, they can be efficacious when combined with interferon. Clinical studies show that interferon-free combination therapies containing ribavirin are also efficacious, suggesting that an interferon-free therapy could be adopted in the near future. However, generation of drug resistant mutants and cross resistance to other drugs could impair the efficacy of the treatment. Therefore, understanding the mechanism of HCV resistance to ribavirin and cross resistance to other antiviral drugs could be of major importance. Methods We tested the ability of a J6/JFH1 derived HCV ribavirin resistant mutant to grow in tissue cultured Huh7D cells in the presence of the mutagen 5-Fluorouracil and the nucleoside analog 2′-C-Methylcytidine. Virus replication was assessed by detecting HCV antigens by immunofluorescence and by titrating virus present in the supernatants. Recovered viruses were amplified by RT-PCR and sequenced. Results The sensitivity of HCV-RR relative to parental J6/JFH1 to the tested drugs varied. HCV-RR was more resistant than J6/JFH1 to 5-Fluorouracil but was not more resistant than J6/JFH1 to 2′-C-Methylcytidine. Growth of HCV-RR in 5-Fluorouracil allowed the selection of an HCV-RR derived mutant resistant to 5-Fluorouracil (HCV-5FU). HCV-5FU grows to moderate levels in the presence of high concentrations of 5-Fluorouracil and to parental levels in the absence of the drug. Sequence of its genome shows that HCV-5FU accumulated multiple synonymous and non-synonymous mutations. Conclusions These results indicate that determinants of resistance to ribavirin could also confer resistance to other anti-HCV drugs, shedding light toward understanding the mechanism of action of ribavirin and highlighting the importance of combination drug selection for HCV treatment. The results also show that it is possible to select a 5-Fluorouracil HCV

  11. Glycolysis Inhibition Inactivates ABC Transporters to Restore Drug Sensitivity in Malignant Cells

    PubMed Central

    Nakano, Ayako; Tsuji, Daisuke; Miki, Hirokazu; Cui, Qu; Sayed, Salah Mohamed El; Ikegame, Akishige; Oda, Asuka; Amou, Hiroe; Nakamura, Shingen; Harada, Takeshi; Fujii, Shiro; Kagawa, Kumiko; Takeuchi, Kyoko; Sakai, Akira; Ozaki, Shuji; Okano, Kazuma; Nakamura, Takahiro; Itoh, Kohji; Matsumoto, Toshio; Abe, Masahiro

    2011-01-01

    Cancer cells eventually acquire drug resistance largely via the aberrant expression of ATP-binding cassette (ABC) transporters, ATP-dependent efflux pumps. Because cancer cells produce ATP mostly through glycolysis, in the present study we explored the effects of inhibiting glycolysis on the ABC transporter function and drug sensitivity of malignant cells. Inhibition of glycolysis by 3-bromopyruvate (3BrPA) suppressed ATP production in malignant cells, and restored the retention of daunorubicin or mitoxantrone in ABC transporter-expressing, RPMI8226 (ABCG2), KG-1 (ABCB1) and HepG2 cells (ABCB1 and ABCG2). Interestingly, although side population (SP) cells isolated from RPMI8226 cells exhibited higher levels of glycolysis with an increased expression of genes involved in the glycolytic pathway, 3BrPA abolished Hoechst 33342 exclusion in SP cells. 3BrPA also disrupted clonogenic capacity in malignant cell lines including RPMI8226, KG-1, and HepG2. Furthermore, 3BrPA restored cytotoxic effects of daunorubicin and doxorubicin on KG-1 and RPMI8226 cells, and markedly suppressed subcutaneous tumor growth in combination with doxorubicin in RPMI8226-implanted mice. These results collectively suggest that the inhibition of glycolysis is able to overcome drug resistance in ABC transporter-expressing malignant cells through the inactivation of ABC transporters and impairment of SP cells with enhanced glycolysis as well as clonogenic cells. PMID:22073292

  12. Re-sensitizing drug-resistant bacteria to antibiotics by designing Antisense Therapeutics

    NASA Astrophysics Data System (ADS)

    Courtney, Colleen; Chatterjee, Anushree

    2014-03-01

    ``Super-bugs'' or ``multi-drug resistant organisms'' are a serious international health problem, with devastating consequences to patient health care. The Center for Disease Control has identified antibiotic resistance as one of the world's most pressing public health problems as a significant fraction of bacterial infections contracted are drug resistant. Typically, antibiotic resistance is encoded by ``resistance-genes'' which express proteins that carryout the resistance causing functions inside the bacterium. We present a RNA based therapeutic strategy for designing antimicrobials capable of re-sensitizing resistant bacteria to antibiotics by targeting labile regions of messenger RNAs encoding for resistance-causing proteins. We perform in silico RNA secondary structure modeling to identify labile target regions in an mRNA of interest. A synthetic biology approach is then used to administer antisense nucleic acids to our model system of ampicillin resistant Escherichia coli. Our results show a prolonged lag phase and decrease in viability of drug-resistant E. colitreated with antisense molecules. The antisense strategy can be applied to alter expression of other genes in antibiotic resistance pathways or other pathways of interest.

  13. Sensitivity of drug-resistant mutants of hepatitis B virus to poly-IC.

    PubMed

    Zhou, Q; Chen, E; Chen, L; Nong, Y; Cheng, X; He, M; Tang, H

    2014-01-01

    The long-term benefits of antiviral treatment are limited by the resistance of hepatitis B virus (HBV). However, the effect of interferon (IFN)α treatment on drug-resistant HBVs is so far unknown. We, therefore, investigated the effects of IFN-α inducer poly-IC on the replication of HBV mutants resistant to drugs such as lamivudine (LAM), adefovir dipivoxil (ADV) and entecavir (ETV) in mice. HBV DNA and HBV DNA intermediate (RI) were employed as markers of the virus replication and 2',5'-oligoadenylate synthase (OAS) mRNA as a marker of IFN-α/β induction. Poly-IC inhibited wtHBV replication and increased levels of OAS mRNA. Compared to the wt virus, the capacity of virus replication was reduced in most LAMr and ETVr mutants except those with mutations rtM(204V+L180M+V173L), and was similary in the ADVr mutants except rt(A121V+N236T). The virus replication was reduced after poly-IC treatment with LAMr and ADVr mutants similary to the wt virus. In contrast, ETVr mutants were resistant to the poly-IC treatment. In conclusion, the capacity of HBV replication and the sensitivity to IFN therapy are influenced by drug-resistant mutations. The IFN therapy may effectively inhibit HBV replication in particular in patients with LAMr or ADVr mutations but not in patients with ETVr mutations.

  14. Clinically immune hosts as a refuge for drug-sensitive malaria parasites.

    PubMed

    Klein, Eili Y; Smith, David L; Boni, Maciej F; Laxminarayan, Ramanan

    2008-04-25

    Mutations in Plasmodium falciparum that confer resistance to first-line antimalarial drugs have spread throughout the world from a few independent foci, all located in areas that were likely characterized by low or unstable malaria transmission. One of the striking differences between areas of low or unstable malaria transmission and hyperendemic areas is the difference in the size of the population of immune individuals. However, epidemiological models of malaria transmission have generally ignored the role of immune individuals in transmission, assuming that they do not affect the fitness of the parasite. This model reconsiders the role of immunity in the dynamics of malaria transmission and its impact on the evolution of antimalarial drug resistance under the assumption that immune individuals are infectious. The model is constructed as a two-stage susceptible-infected-susceptible (SIS) model of malaria transmission that assumes that individuals build up clinical immunity over a period of years. This immunity reduces the frequency and severity of clinical symptoms, and thus their use of drugs. It also reduces an individual's level of infectiousness, but does not impact the likelihood of becoming infected. Simulations found that with the introduction of resistance into a population, clinical immunity can significantly alter the fitness of the resistant parasite, and thereby impact the ability of the resistant parasite to spread from an initial host by reducing the effective reproductive number of the resistant parasite as transmission intensity increases. At high transmission levels, despite a higher basic reproductive number, R0, the effective reproductive number of the resistant parasite may fall below the reproductive number of the sensitive parasite. These results suggest that high-levels of clinical immunity create a natural ecological refuge for drug-sensitive parasites. This provides an epidemiological rationale for historical patterns of resistance

  15. Effects of antihypertensive drugs and exercise training on insulin sensitivity in spontaneously hypertensive rats.

    PubMed

    Guo, Qi; Minami, Naoyoshi; Mori, Nobuyoshi; Nagasaka, Makoto; Ito, Osamu; Kurosawa, Hajime; Kanazawa, Masayuki; Kohzuki, Masahiro

    2008-03-01

    We examined the effects of antihypertensive drugs, exercise training, and combinations thereof on insulin sensitivity (IS), and the association between this relation and sympathetic activity, muscle fiber composition, and capillary density in spontaneously hypertensive rats (SHR). Six-week-old male SHR were allocated to 7 groups: a control group (C), and groups treated with azelnidipine (Aze) (a calcium channel blocker), olmesartan (Olm) (an angiotensin II type 1 receptor blocker), exercise training (Exe), and combinations of drugs and exercise training (Aze+Exe, Olm+Exe, and Olm+Aze+Exe). At age 18 weeks, IS and sympathetic activity were evaluated by an euglycemic hyperinsulinemic glucose clamp technique and power spectral analysis of systolic blood pressure, respectively. After the experiments, capillary density and muscle fiber composition in soleus muscle were examined. Aze or Exe alone significantly increased IS associated with a significant reduction in sympathetic activity. Olm alone tended to increase IS with little change in sympathetic activity. Aze, Olm, or Exe significantly increased the capillary density and percentage of insulin-sensitive type I fiber. A combination of Aze and Exe or a combination of Olm and Exe tended to increase IS compared with each drug therapy alone. There were significant correlations between IS and sympathetic activity, capillary density, and the percentage of type I fiber in all the rats. We found that Aze improved IS more substantially compared with Olm in SHR. We also found that Aze, Olm, Exe, and combinations thereof improved IS, probably through the modulation of sympathetic activity or capillarity and muscle fiber type in skeletal muscles.

  16. Immunoassay-Based Drug Tests Are Inadequately Sensitive for Medication Compliance Monitoring in Patients Treated for Chronic Pain.

    PubMed

    Snyder, Marion L; Fantz, Corrine R; Melanson, Stacy

    2017-02-01

    Enzyme immunoassays (EIA) have notable limitations for monitoring therapeutic compliance in pain management. Chromatography coupled with mass spectrometry provides definitive results and superior sensitivity and specificity over traditional EIA testing. To analyze and compare the sensitivity of EIA results together with known prescriptions to liquid chromatography-tandem mass spectrometry (LC-MS/MS) for monitoring drug use (and abuse) in patients treated for chronic pain. A total of 530 urine samples from patients being treated for chronic pain were studied. Pain management clinic in the United States. The samples were tested for a profile of chronic pain medications and illicit drugs with commercially available EIA kits followed by analysis with Agilent LC-MS/MS system. The EIAs exhibited poor sensitivity and high rates of false negative results in the pain management setting. For example, 21% of EIA for opiates show false negative results. Mass spectrometry methods were more sensitive, detected a broader range of drugs and metabolites, and could detect non-prescribed drug use and simulations in compliance. Patients do not always accurately report drug use information, and some drugs do not have EIA methods available for comparative purposes. Mass spectrometry is a more robust and reliable method for detection of drugs used in the pain management setting. Due to the extent of undisclosed use and abuse of medications and illicit drugs, LC-MS/MS testing is necessary for adequate and accurate drug detection. In addition, LC-MS/MS methods are superior in terms of sensitivity and number of compounds that can be screened, making this a better method for use in pain management. Key words: Pain management, enzyme immunoassays, mass spectrometry, urine drug testing, prescription status, compliance.

  17. Microenvironment-derived HGF overcomes genetically determined sensitivity to anti-MET drugs.

    PubMed

    Pennacchietti, Selma; Cazzanti, Manuela; Bertotti, Andrea; Rideout, William M; Han, May; Gyuris, Jeno; Perera, Timothy; Comoglio, Paolo M; Trusolino, Livio; Michieli, Paolo

    2014-11-15

    Cell-based drug screenings indicate that tumors displaying c-MET gene amplification are "addicted" to MET signaling and therefore are very sensitive to MET-targeted agents. However, these screenings were conducted in the absence of the MET ligand, hepatocyte growth factor (HGF), which is abundant in the tumor microenvironment. Sensitivity of six MET-addicted human tumor cells to three MET kinase inhibitors (JNJ-38877605, PHA-665752, crizotinib) and one antagonistic anti-MET antibody (DN30 Fab) was analyzed in the absence or presence of HGF, in a stroma-tumor coculture system, and by combining anti-MET drugs with an HGF neutralizing antibody (ficlatuzumab) in human HGF knock-in mice bearing c-MET-amplified tumors. In all models examined, HGF promoted resistance to MET-targeted agents, affecting both their potency and efficacy. HGF-induced resistance was due to restoration of physiologic GAB1-mediated PI3K activation that compensated for loss of aberrant HER3-dependent PI3K signaling. Ficlatuzumab restored sensitivity to MET-targeted agents in coculture systems and overcame resistance to JNJ-38877605, crizotinib, and DN30 Fab in human HGF knock-in mice. These data suggest that c-MET-amplified tumor cells-which normally exhibit ligand-independent, constitutive MET activation-become dependent on HGF for survival upon pharmacologic MET inhibition. Because HGF is frequently overexpressed in human cancer, this mechanism may represent a major cause of resistance to anti-MET therapies. The ability of ficlatuzumab to overcome HGF-mediated resistance generates proof of principle that vertical inhibition of both a tyrosine kinase receptor and its ligand can be therapeutically beneficial and opens new perspectives for the treatment of MET-dependent tumors.

  18. PPO/PEO modified hollow fiber membranes improved sensitivity of 3D cultured hepatocytes to drug toxicity via suppressing drug adsorption on membranes.

    PubMed

    Shen, Chong; Meng, Qin; He, Wenjuan; Wang, Qichen; Zhang, Guoliang

    2014-11-01

    The three dimensional (3D) cell culture in polymer-based micro system has become a useful tool for in vitro drug discovery. Among those polymers, polysulfone hollow fiber membrane (PSf HFM) is commonly used to create a microenvironment for cells. However, the target drug may adsorb on the polymeric surface, and this elicits negative impacts on cell exposure due to the reduced effective drug concentration in culture medium. In order to reduce the drug adsorption, PSf membrane were modified with hydrophilic Pluronic (PEO-b-PPO-b-PEO) copolymers, L121, P123 and F127 (PEO contents increase from 10%, 30% to 70%), by physical adsorption. As a result, the hydrophilicity of HFMs increased at an order of PSfF127>P123>L121 HFMs. The three modified membrane all showed significant resistance to adsorption of acid/neutral drugs. More importantly, the adsorption of base drugs were largely reduced to an average value of 11% on the L121 HFM. The improved resistance to drug adsorption could be attributed to the synergy of hydrophobic/neutrally charged PPO and hydrophilic PEO. The L121 HFM was further assessed by evaluating the drug hepatotoxicity in 3D culture of hepatocytes. The base drugs, clozapine and doxorubicin, showed more sensitive hepatotoxicity on hepatocytes in L121 HFM than in PSf HFM, while the acid drug, salicylic acid, showed the similar hepatotoxicity to hepatocytes in both HFMs. Our finding suggests that PSf HFM modified by PEO-b-PPO-b-PEO copolymers can efficiently resist the drug adsorption onto polymer membrane, and consequently improve the accuracy and sensitivity of in vitro hepatotoxic drug screening. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Validation of a sensitive ion chromatography method for determination of monoethylsulfate in Indinavir sulfate drug substance.

    PubMed

    Prasanna, S John; Sharma, Hemant Kumar; Mukkanti, K; Sivakumaran, M; Pavan Kumar, K S R; Kumar, V Jagadeesh

    2009-12-05

    The present study relates to the optimization of an ion chromatography method to determine the content of monoethylsulfate at very low levels in Indinavir sulfate drug substance, and subsequent validation of the method to prove its suitability, reliability and sensitivity. Monoethylsulfate is a potential impurity of Indinavir sulfate, and may forms during the preparation as well as during storage. The ion chromatography method was developed in such a way that to enhance the detection level by introducing suppressor, and minimizing acquisition time by using suitable buffer of 3.2 mmole of sodium carbonate and 1 mmole of sodium hydrogen carbonate in water as eluent. The retention time of monoethylsulfate was about 9.5 min and the total acquisition time was 25 min. The optimized method was validated to prove its performance characteristics by demonstrating selectivity, sensitivity (limit of detection and quantification), linearity, precision and accuracy. The established limit of detection and quantification of monoethylsulfate in Indinavir sulfate by this method was found to be 24 ng/ml and 74 ng/ml respectively, and the overall percent accuracy (recovery) of samples evaluated at different concentration levels was found to be 97.1, indicating the sensitivity and accuracy of this optimized ion chromatography method.

  20. Peripheral insulin-sensitizer drug metformin ameliorates neuronal insulin resistance and Alzheimer's-like changes.

    PubMed

    Gupta, Amit; Bisht, Bharti; Dey, Chinmoy Sankar

    2011-05-01

    Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide. Pharmacological treatments presently available can slow down the progression of symptoms but can not cure the disease. Currently there is widening recognition that AD is closely associated with impaired insulin signaling and glucose metabolism in brain, suggesting it to be a brain-specific form of diabetes and so also termed as "type 3 diabetes". Hence investigating the role of pharmacological agents that could ameliorate neuronal insulin resistance merit attention in AD therapeutics, however the therapeutics for pathophysiological condition like neuronal insulin resistance itself is largely unknown. In the present study we have determined the effect of metformin on neuronal insulin resistance and AD-associated characteristics in an in vitro model of "type 3 diabetes" by differentiating neuronal cell line Neuro-2a under prolonged presence of insulin. We observed that prolonged hyperinsulinemic conditions in addition to generating insulin resistance also led to development of hallmark AD-associated neuropathological changes. Treatment with metformin sensitized the impaired insulin actions and also prevented appearance of molecular and pathological characteristics observed in AD. The results thus demonstrate possible therapeutic efficacy of peripheral insulin-sensitizer drug metformin in AD by its ability to sensitize neuronal insulin resistance. These findings also provide direct evidences linking hyperinsulinemia and AD and suggest a unique opportunity for prevention and treatment of "type 3 diabetes".

  1. A Translational Approach to Validate In Vivo Anti-Tumor Effects of Chloroquine on Breast Cancer Risk

    DTIC Science & Technology

    2015-07-01

    a well-characterized anti-malarial drug. BACKGROUND: Exposure to chloroquine, an off- patent anti-malarial drug with a 60-year history of use by...BACKGROUND: Exposure to chloroquine, an off- patent anti-malarial drug with a 60-year history of use by millions, reduces the incidence of breast cancer...for an off- patent (which means that no pharmaceutical company owns it) and inexpensive drug. Who is paying for this study? In the early 1990s, a

  2. Simple PCR Assays Improve the Sensitivity of HIV-1 Subtype B Drug Resistance Testing and Allow Linking of Resistance Mutations

    PubMed Central

    Johnson, Jeffrey A.; Li, Jin-Fen; Wei, Xierong; Lipscomb, Jonathan; Bennett, Diane; Brant, Ashley; Cong, Mian-er; Spira, Thomas; Shafer, Robert W.; Heneine, Walid

    2007-01-01

    Background The success of antiretroviral therapy is known to be compromised by drug-resistant HIV-1 at frequencies detectable by conventional bulk sequencing. Currently, there is a need to assess the clinical consequences of low-frequency drug resistant variants occurring below the detection limit of conventional genotyping. Sensitive detection of drug-resistant subpopulations, however, requires simple and practical methods for routine testing. Methodology We developed highly-sensitive and simple real-time PCR assays for nine key drug resistance mutations and show that these tests overcome substantial sequence heterogeneity in HIV-1 clinical specimens. We specifically used early wildtype virus samples from the pre-antiretroviral drug era to measure background reactivity and were able to define highly-specific screening cut-offs that are up to 67-fold more sensitive than conventional genotyping. We also demonstrate that sequencing the mutation-specific PCR products provided a direct and novel strategy to further detect and link associated resistance mutations, allowing easy identification of multi-drug-resistant variants. Resistance mutation associations revealed in mutation-specific amplicon sequences were verified by clonal sequencing. Significance Combined, sensitive real-time PCR testing and mutation-specific amplicon sequencing provides a powerful and simple approach that allows for improved detection and evaluation of HIV-1 drug resistance mutations. PMID:17653265

  3. A sensitive multidimensional method for the detection, characterization, and quantification of trace free drug species in antibody-drug conjugate samples using mass spectral detection.

    PubMed

    Birdsall, Robert E; McCarthy, Sean M; Janin-Bussat, Marie Claire; Perez, Michel; Haeuw, Jean-François; Chen, Weibin; Beck, Alain

    2016-01-01

    Conjugation processes and stability studies associated with the production and shelf life of antibody-drug conjugates (ADCs) can result in free (non-conjugated) drug species. These free drug species can increase the risk to patients and reduce the efficacy of the ADC. Despite stringent purification steps, trace levels of free drug species may be present in formulated ADCs, reducing the therapeutic window. The reduction of sample preparation steps through the incorporation of multidimensional techniques has afforded analysts more efficient methods to assess trace drug species. Multidimensional methods coupling size-exclusion and reversed phase liquid chromatography with ultra-violet detection (SEC-RPLC/UV) have been reported, but offer limited sensitivity and can limit method optimization. The current study addresses these challenges with a multidimensional method that is specific, sensitive, and enables method control in both dimensions via coupling of an on-line solid phase extraction column to RPLC with mass spectral detection (SPE-RPLC/MS). The proposed method was evaluated using an antibody-fluorophore conjugate (AFC) as an ADC surrogate to brentuximab vedotin and its associated parent maleimide-val-cit-DSEA payload and the derived N-acetylcysteine adduct formed during the conjugation process. Assay sensitivity was found to be 2 orders more sensitive using MS detection in comparison to UV-based detection with a nominal limit of quantitation of 0.30 ng/mL (1.5 pg on-column). Free-drug species were present in an unadulterated ADC surrogate sample at concentrations below 7 ng/mL, levels not detectable by UV alone. The proposed SPE-RPLC/MS method provides a high degree of specificity and sensitivity in the assessment of trace free drug species and offers improved control over each dimension, enabling straightforward integration into existing or novel workflows.

  4. A sensitive multidimensional method for the detection, characterization, and quantification of trace free drug species in antibody-drug conjugate samples using mass spectral detection

    PubMed Central

    Birdsall, Robert E.; McCarthy, Sean M.; Janin-Bussat, Marie Claire; Perez, Michel; Haeuw, Jean-François; Chen, Weibin; Beck, Alain

    2016-01-01

    abstract Conjugation processes and stability studies associated with the production and shelf life of antibody-drug conjugates (ADCs) can result in free (non-conjugated) drug species. These free drug species can increase the risk to patients and reduce the efficacy of the ADC. Despite stringent purification steps, trace levels of free drug species may be present in formulated ADCs, reducing the therapeutic window. The reduction of sample preparation steps through the incorporation of multidimensional techniques has afforded analysts more efficient methods to assess trace drug species. Multidimensional methods coupling size-exclusion and reversed phase liquid chromatography with ultra-violet detection (SEC-RPLC/UV) have been reported, but offer limited sensitivity and can limit method optimization. The current study addresses these challenges with a multidimensional method that is specific, sensitive, and enables method control in both dimensions via coupling of an on-line solid phase extraction column to RPLC with mass spectral detection (SPE-RPLC/MS). The proposed method was evaluated using an antibody-fluorophore conjugate (AFC) as an ADC surrogate to brentuximab vedotin and its associated parent maleimide-val-cit-DSEA payload and the derived N-acetylcysteine adduct formed during the conjugation process. Assay sensitivity was found to be 2 orders more sensitive using MS detection in comparison to UV-based detection with a nominal limit of quantitation of 0.30 ng/mL (1.5 pg on-column). Free-drug species were present in an unadulterated ADC surrogate sample at concentrations below 7 ng/mL, levels not detectable by UV alone. The proposed SPE-RPLC/MS method provides a high degree of specificity and sensitivity in the assessment of trace free drug species and offers improved control over each dimension, enabling straightforward integration into existing or novel workflows. PMID:26651262

  5. Merging Traditional Chinese Medicine with Modern Drug Discovery Technologies to Find Novel Drugs and Functional Foods

    PubMed Central

    Graziose, Rocky; Lila, Mary Ann; Raskin, Ilya

    2011-01-01

    Traditional Chinese Medicines (TCM) are rapidly gaining attention in the West as sources of new drugs, dietary supplements and functional foods. However, lack of consistent manufacturing practices and quality standards, fear of adulteration, and perceived deficiencies in scientific validation of efficacy and safety impede worldwide acceptance of TCM. In addition, Western pharmaceutical industries and regulatory agencies are partial toward single ingredient drugs based on synthetic molecules, and skeptical of natural product mixtures. This review concentrates on three examples of TCM-derived pharmaceuticals and functional foods that have, despite these usual obstacles, risen to wide acceptance in the West based on their remarkable performance in recent scientific investigations. They are: Sweet wormwood (Artemisia annua), the source of artemisinin, which is the currently preferred single compound anti-malarial drug widely used in combination therapies and recently approved by US FDA; Thunder god vine (Tripterygium wilfordii) which is being developed as a botanical drug for rheumatoid arthritis; and green tea (Camellia sinensis) which is used as a functional beverage and a component of dietary supplements. PMID:20156139

  6. Merging traditional Chinese medicine with modern drug discovery technologies to find novel drugs and functional foods.

    PubMed

    Graziose, Rocky; Lila, Mary Ann; Raskin, Ilya

    2010-03-01

    Traditional Chinese Medicines (TCM) are rapidly gaining attention in the West as sources of new drugs, dietary supplements and functional foods. However, lack of consistent manufacturing practices and quality standards, fear of adulteration, and perceived deficiencies in scientific validation of efficacy and safety impede worldwide acceptance of TCM. In addition, Western pharmaceutical industries and regulatory agencies are partial toward single ingredient drugs based on synthetic molecules, and skeptical of natural product mixtures. This review concentrates on three examples of TCM-derived pharmaceuticals and functional foods that have, despite these usual obstacles, risen to wide acceptance in the West based on their remarkable performance in recent scientific investigations. They are: Sweet wormwood (Artemisia annua), the source of artemisinin, which is the currently preferred single compound anti-malarial drug widely used in combination therapies and recently approved by US FDA; Thunder god vine (Tripterygium wilfordii) which is being developed as a botanical drug for rheumatoid arthritis; and green tea (Camellia sinensis) which is used as a functional beverage and a component of dietary supplements.

  7. Phosphatidylinositol 3-kinase inhibition broadly sensitizes glioblastoma cells to death receptor- and drug-induced apoptosis.

    PubMed

    Opel, Daniela; Westhoff, Mike-Andrew; Bender, Ariane; Braun, Veit; Debatin, Klaus-Michael; Fulda, Simone

    2008-08-01

    The aberrant activity of the phosphatidylinositol 3-kinase (PI3K) pathway has been reported to correlate with adverse clinical outcome in human glioblastoma in vivo. However, the question of how this survival network can be successfully targeted to restore the sensitivity of glioblastoma to apoptosis induction has not yet been answered. Here, we report that inhibition of PI3K by LY294002 broadly sensitizes wild-type and mutant PTEN glioblastoma cells to both death receptor- and chemotherapy-induced apoptosis, whereas mammalian target of rapamycin (mTOR) inhibition is not sufficient to restore apoptosis sensitivity. LY294002 significantly enhances apoptosis triggered by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), agonistic anti-CD95 antibodies, or several anticancer drugs (i.e., doxorubicin, etoposide, and vincristine) in a highly synergistic manner. In addition, LY294002 cooperates with TRAIL or doxorubicin to suppress colony formation, thus also showing a strong effect on long-term survival. Similarly, genetic knockdown of PI3K subunits p110alpha and/or p110beta by RNA interference (RNAi) primes glioblastoma cells for TRAIL- or doxorubicin-mediated apoptosis. In contrast to PI3K inhibition, pharmacologic or genetic blockade of mTOR by RAD001 (everolimus), rapamycin, or RNAi fails to enhance TRAIL- or doxorubicin-induced apoptosis. Analysis of apoptosis pathways reveals that PI3K inhibition acts in concert with TRAIL or doxorubicin to trigger mitochondrial membrane permeabilization, caspase activation, and caspase-dependent apoptosis, which are abolished by the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Most importantly, PI3K inhibition by LY294002 sensitizes primary cultured glioblastoma cells obtained from surgical specimens to TRAIL- or chemotherapy-induced cell death. By showing that PI3K inhibition broadly primes glioblastoma cells for apoptosis, our findings provide the rationale for using PI3K inhibitors in

  8. Activating mutations and senescence secretome: new insights into HER2 activation, drug sensitivity and metastatic progression.

    PubMed

    Acharyya, Swarnali

    2013-04-23

    HER2 amplification and overexpression is observed in approximately 20% of breast cancers and is strongly associated with poor prognosis and therapeutic responsiveness to HER2 targeted agents. A recent study by Bose and colleagues suggests that another subset of breast cancer patients without HER2 amplification but with activating HER2 mutation might also benefit from existing HER2-targeted agents and the authors functionally characterize these somatic mutations in experimental models. In a second study on HER2-driven breast cancer, Angelini and colleagues investigate how the constitutively active, truncated carboxy-terminal fragment of HER2, p95HER2, promotes metastatic progression through non-cellautonomous secretion of factors from senescent cells. These new findings advance our understanding of HER2 biology in the context of HER2 activation as well as offer new insights into our understanding of drug sensitivity and metastatic progression.

  9. Assessment of substance abuse liability in rodents: self-administration, drug discrimination, and locomotor sensitization.

    PubMed

    Paterson, Neil E

    2012-09-01

    Assessing abuse liability is a crucial step in the development of a novel chemical entity (NCE) with central nervous system (CNS) activity or with chemical or pharmacological properties in common with known abused substances. Rodent assessment of abuse liability is highly attractive due to its relatively low cost and high predictive validity. Described in this unit are three rodent assays commonly used to provide data on the potential for abuse liability based on the acute effects of NCEs: specifically, self-administration, drug discrimination, and locomotor sensitization. As these assays provide insight into the potential abuse liability of NCEs as well as in vivo pharmacological mechanism(s) of action, they should form a key part of the development process for novel therapeutics aimed at treating CNS disorders.

  10. Candida albicans and Candida tropicalis in oral candidosis: quantitative analysis, exoenzyme activity, and antifungal drug sensitivity.

    PubMed

    da Costa, Karen Regina Carim; Ferreira, Joseane Cristina; Komesu, Marilena Chinali; Candido, Regina Celia

    2009-02-01

    Candida albicans and C. tropicalis obtained from whole saliva of patients presenting signs of oral candidosis were assayed for quantification of colony forming units, exoenzyme activity (phospholipase and proteinase) and antifungal drug sensitivity (amphotericin B, fluconazole and itraconazole) by the reference method of the Clinical and Laboratory Standards Institute. The number of colony forming units per milliliter varied according to the Candida species involved and whether a single or mixed infection was present. Proteinase activity was observed in both C. albicans and C. tropicalis, but phospholipase activity was noted only in C. albicans. In vitro resistance to antifungals was verified in both species, but C. tropicalis appears to be more resistant to the tested antifungals than C. albicans.

  11. Design of Probabilistic Random Forests with Applications to Anticancer Drug Sensitivity Prediction

    PubMed Central

    Rahman, Raziur; Haider, Saad; Ghosh, Souparno; Pal, Ranadip

    2015-01-01

    Random forests consisting of an ensemble of regression trees with equal weights are frequently used for design of predictive models. In this article, we consider an extension of the methodology by representing the regression trees in the form of probabilistic trees and analyzing the nature of heteroscedasticity. The probabilistic tree representation allows for analytical computation of confidence intervals (CIs), and the tree weight optimization is expected to provide stricter CIs with comparable performance in mean error. We approached the ensemble of probabilistic trees’ prediction from the perspectives of a mixture distribution and as a weighted sum of correlated random variables. We applied our methodology to the drug sensitivity prediction problem on synthetic and cancer cell line encyclopedia dataset and illustrated that tree weights can be selected to reduce the average length of the CI without increase in mean error. PMID:27081304

  12. Competition between novelty and cocaine conditioned reward is sensitive to drug dose and retention interval

    PubMed Central

    Reichel, Carmela M.; Bevins, Rick A.

    2010-01-01

    The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at www.apa.org/pubs/journals/bne The conditioned rewarding effects of novelty compete with those of cocaine for control over choice behavior using a place-conditioning task. The purpose of the present study was to use multiple doses of cocaine to determine the extent of this competition and to determine whether novelty's impact on cocaine reward was maintained over an abstinence period. In Experiment 1, rats were conditioned with cocaine (7.5, 20, or 30 mg/kg, IP) to prefer one side of an unbiased place conditioning apparatus relative to the other. In a subsequent phase, all rats received alternating daily confinements to the previously cocaine-paired and unpaired sides of the apparatus. During this phase, half the rats had access to a novel object on their initially unpaired side; the remaining rats did not receive objects. The ability of novelty to compete with cocaine in a drug-free and cocaine-challenge test was sensitive to cocaine dose. In Experiment 2, a place preference was established with 10 mg/kg cocaine and testing occurred after 1, 14, or 28 day retention intervals. Findings indicate that choice behaviors mediated by cocaine conditioning are reduced with the passing of time. Taken together, competition between cocaine and novelty conditioned rewards are sensitive to drug dose and retention interval. PMID:20141289

  13. Highly Sensitive and Validated Spectrophotometric Technique for the Assay of Some Antidepressant Drugs

    NASA Astrophysics Data System (ADS)

    Deepakumari, H. N.; Prashanth, M. K.; Kumar, B. C. Vasantha; Revanasiddappa, H. D.

    2015-01-01

    The present paper describes a simple, rapid, reproducible, and highly sensitive spectrophotometric method for the determination of the tricyclic antidepressant drugs: amitriptyline hydrochloride (AMT), imipramine hydrochloride (IMH), clomipramine hydrochloride (CPH) and desipramine hydrochloride (DPH) in pure and in pharmaceutical preparations. The method is based on the bromination of the above drugs with known excess of bromine. The unreacted bromine is determined based on its ability to bleach the dye methyl red quantitatively at 520 nm. Regression analysis of Beer-Lambert plots showed a good correlation in the concentration range 0.0-2.5, 0-1.4, 0-1.4, and 0-1.0 μg/ml for AMT, IMH, CPH, and DPH, respectively. The molar absorptivity values were found to be 0.65 × 105, 1.41 × 105, 1.93 × 105, and 2.96 × 105l/mol/cm, with the corresponding Sandell's sensitivity values were 0.0048, 0.0022, 0.0018, and 0.0010 μg/cm2 for AMT, IMH, CPH, and DPH, respectively. The limits of detection (LOD) and quantification (LOQ) are also reported for the developed method. Intra- and inter-day accuracy and precision was established according to the current ICH guidelines. Application of the procedure to the analysis of various pharmaceutical preparations gave reproducible and accurate results. Further, the validity of the proposed method was confirmed by applying the standard addition technique, and the results obtained are in good agreement with those obtained by the official method.

  14. Reduced mtDNA copy number increases the sensitivity of tumor cells to chemotherapeutic drugs

    PubMed Central

    Mei, H; Sun, S; Bai, Y; Chen, Y; Chai, R; Li, H

    2015-01-01

    Many cancer drugs are toxic to cells by activating apoptotic pathways. Previous studies have shown that mitochondria have key roles in apoptosis in mammalian cells, but the role of mitochondrial DNA (mtDNA) copy number variation in the pathogenesis of tumor cell apoptosis remains largely unknown. We used the HEp-2, HNE2, and A549 tumor cell lines to explore the relationship between mtDNA copy number variation and cell apoptosis. We first induced apoptosis in three tumor cell lines and one normal adult human skin fibroblast cell line (HSF) with cisplatin (DDP) or doxorubicin (DOX) treatment and found that the mtDNA copy number significantly increased in apoptotic tumor cells, but not in HSF cells. We then downregulated the mtDNA copy number by transfection with shRNA-TFAM plasmids or treatment with ethidium bromide and found that the sensitivity of tumor cells to DDP or DOX was significantly increased. Furthermore, we observed that levels of reactive oxygen species (ROS) increased significantly in tumor cells with lower mtDNA copy numbers, and this might be related to a low level of antioxidant gene expression. Finally, we rescued the increase of ROS in tumor cells with lipoic acid or N-acetyl-L-cysteine and found that the apoptosis rate decreased. Our studies suggest that the increase of mtDNA copy number is a self-protective mechanism of tumor cells to prevent apoptosis and that reduced mtDNA copy number increases ROS levels in tumor cells, increases the tumor cells' sensitivity to chemotherapeutic drugs, and increases the rate of apoptosis. This research provides evidence that mtDNA copy number variation might be a promising new therapeutic target for the clinical treatment of tumors. PMID:25837486

  15. Flow perfusion effects on three-dimensional culture and drug sensitivity of Ewing sarcoma

    PubMed Central

    Santoro, Marco; Lamhamedi-Cherradi, Salah-Eddine; Menegaz, Brian A.; Ludwig, Joseph A.; Mikos, Antonios G.

    2015-01-01

    Three-dimensional tumor models accurately describe different aspects of the tumor m